// Sources flattened with hardhat v2.9.9 https://hardhat.org

// File interfaces/IInterchainGasPaymaster.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.6.11;

/**
 * @title IInterchainGasPaymaster
 * @notice Manages payments on a source chain to cover gas costs of relaying
 * messages to destination chains.
 */
interface IInterchainGasPaymaster {
    function payForGas(
        bytes32 _messageId,
        uint32 _destinationDomain,
        uint256 _gas,
        address _refundAddress
    ) external payable;
}


// File interfaces/IInterchainSecurityModule.sol


pragma solidity >=0.6.11;

interface IInterchainSecurityModule {
    /**
     * @notice Returns an enum that represents the type of security model
     * encoded by this ISM.
     * @dev Relayers infer how to fetch and format metadata.
     */
    function moduleType() external view returns (uint8);

    /**
     * @notice Defines a security model responsible for verifying interchain
     * messages based on the provided metadata.
     * @param _metadata Off-chain metadata provided by a relayer, specific to
     * the security model encoded by the module (e.g. validator signatures)
     * @param _message Hyperlane encoded interchain message
     * @return True if the message was verified
     */
    function verify(bytes calldata _metadata, bytes calldata _message)
        external
        returns (bool);
}

interface ISpecifiesInterchainSecurityModule {
    function interchainSecurityModule()
        external
        view
        returns (IInterchainSecurityModule);
}


// File interfaces/IMailbox.sol


pragma solidity >=0.8.0;

interface IMailbox {
    function localDomain() external view returns (uint32);

    function dispatch(
        uint32 _destinationDomain,
        bytes32 _recipientAddress,
        bytes calldata _messageBody
    ) external returns (bytes32);

    function process(bytes calldata _metadata, bytes calldata _message)
        external;

    function count() external view returns (uint32);

    function root() external view returns (bytes32);

    function latestCheckpoint() external view returns (bytes32, uint32);

    function recipientIsm(address _recipient)
        external
        view
        returns (IInterchainSecurityModule);
}


// File @openzeppelin/contracts-upgradeable/utils/AddressUpgradeable.sol@v4.8.0


// OpenZeppelin Contracts (last updated v4.8.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @dev Collection of functions related to the address type
 */
library AddressUpgradeable {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
     * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
     *
     * _Available since v4.8._
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                // only check isContract if the call was successful and the return data is empty
                // otherwise we already know that it was a contract
                require(isContract(target), "Address: call to non-contract");
            }
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    /**
     * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason or using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    function _revert(bytes memory returndata, string memory errorMessage) private pure {
        // Look for revert reason and bubble it up if present
        if (returndata.length > 0) {
            // The easiest way to bubble the revert reason is using memory via assembly
            /// @solidity memory-safe-assembly
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert(errorMessage);
        }
    }
}


// File @openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol@v4.8.0


// OpenZeppelin Contracts (last updated v4.8.0) (proxy/utils/Initializable.sol)

pragma solidity ^0.8.2;

/**
 * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
 * behind a proxy. Since proxied contracts do not make use of a constructor, it's common to move constructor logic to an
 * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
 * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
 *
 * The initialization functions use a version number. Once a version number is used, it is consumed and cannot be
 * reused. This mechanism prevents re-execution of each "step" but allows the creation of new initialization steps in
 * case an upgrade adds a module that needs to be initialized.
 *
 * For example:
 *
 * [.hljs-theme-light.nopadding]
 * ```
 * contract MyToken is ERC20Upgradeable {
 *     function initialize() initializer public {
 *         __ERC20_init("MyToken", "MTK");
 *     }
 * }
 * contract MyTokenV2 is MyToken, ERC20PermitUpgradeable {
 *     function initializeV2() reinitializer(2) public {
 *         __ERC20Permit_init("MyToken");
 *     }
 * }
 * ```
 *
 * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
 * possible by providing the encoded function call as the `_data` argument to {ERC1967Proxy-constructor}.
 *
 * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
 * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
 *
 * [CAUTION]
 * ====
 * Avoid leaving a contract uninitialized.
 *
 * An uninitialized contract can be taken over by an attacker. This applies to both a proxy and its implementation
 * contract, which may impact the proxy. To prevent the implementation contract from being used, you should invoke
 * the {_disableInitializers} function in the constructor to automatically lock it when it is deployed:
 *
 * [.hljs-theme-light.nopadding]
 * ```
 * /// @custom:oz-upgrades-unsafe-allow constructor
 * constructor() {
 *     _disableInitializers();
 * }
 * ```
 * ====
 */
abstract contract Initializable {
    /**
     * @dev Indicates that the contract has been initialized.
     * @custom:oz-retyped-from bool
     */
    uint8 private _initialized;

    /**
     * @dev Indicates that the contract is in the process of being initialized.
     */
    bool private _initializing;

    /**
     * @dev Triggered when the contract has been initialized or reinitialized.
     */
    event Initialized(uint8 version);

    /**
     * @dev A modifier that defines a protected initializer function that can be invoked at most once. In its scope,
     * `onlyInitializing` functions can be used to initialize parent contracts.
     *
     * Similar to `reinitializer(1)`, except that functions marked with `initializer` can be nested in the context of a
     * constructor.
     *
     * Emits an {Initialized} event.
     */
    modifier initializer() {
        bool isTopLevelCall = !_initializing;
        require(
            (isTopLevelCall && _initialized < 1) || (!AddressUpgradeable.isContract(address(this)) && _initialized == 1),
            "Initializable: contract is already initialized"
        );
        _initialized = 1;
        if (isTopLevelCall) {
            _initializing = true;
        }
        _;
        if (isTopLevelCall) {
            _initializing = false;
            emit Initialized(1);
        }
    }

    /**
     * @dev A modifier that defines a protected reinitializer function that can be invoked at most once, and only if the
     * contract hasn't been initialized to a greater version before. In its scope, `onlyInitializing` functions can be
     * used to initialize parent contracts.
     *
     * A reinitializer may be used after the original initialization step. This is essential to configure modules that
     * are added through upgrades and that require initialization.
     *
     * When `version` is 1, this modifier is similar to `initializer`, except that functions marked with `reinitializer`
     * cannot be nested. If one is invoked in the context of another, execution will revert.
     *
     * Note that versions can jump in increments greater than 1; this implies that if multiple reinitializers coexist in
     * a contract, executing them in the right order is up to the developer or operator.
     *
     * WARNING: setting the version to 255 will prevent any future reinitialization.
     *
     * Emits an {Initialized} event.
     */
    modifier reinitializer(uint8 version) {
        require(!_initializing && _initialized < version, "Initializable: contract is already initialized");
        _initialized = version;
        _initializing = true;
        _;
        _initializing = false;
        emit Initialized(version);
    }

    /**
     * @dev Modifier to protect an initialization function so that it can only be invoked by functions with the
     * {initializer} and {reinitializer} modifiers, directly or indirectly.
     */
    modifier onlyInitializing() {
        require(_initializing, "Initializable: contract is not initializing");
        _;
    }

    /**
     * @dev Locks the contract, preventing any future reinitialization. This cannot be part of an initializer call.
     * Calling this in the constructor of a contract will prevent that contract from being initialized or reinitialized
     * to any version. It is recommended to use this to lock implementation contracts that are designed to be called
     * through proxies.
     *
     * Emits an {Initialized} event the first time it is successfully executed.
     */
    function _disableInitializers() internal virtual {
        require(!_initializing, "Initializable: contract is initializing");
        if (_initialized < type(uint8).max) {
            _initialized = type(uint8).max;
            emit Initialized(type(uint8).max);
        }
    }

    /**
     * @dev Internal function that returns the initialized version. Returns `_initialized`
     */
    function _getInitializedVersion() internal view returns (uint8) {
        return _initialized;
    }

    /**
     * @dev Internal function that returns the initialized version. Returns `_initializing`
     */
    function _isInitializing() internal view returns (bool) {
        return _initializing;
    }
}


// File @openzeppelin/contracts-upgradeable/utils/ContextUpgradeable.sol@v4.8.0


// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract ContextUpgradeable is Initializable {
    function __Context_init() internal onlyInitializing {
    }

    function __Context_init_unchained() internal onlyInitializing {
    }
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[50] private __gap;
}


// File @openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol@v4.8.0


// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)

pragma solidity ^0.8.0;


/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract OwnableUpgradeable is Initializable, ContextUpgradeable {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    function __Ownable_init() internal onlyInitializing {
        __Ownable_init_unchained();
    }

    function __Ownable_init_unchained() internal onlyInitializing {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[49] private __gap;
}


// File @openzeppelin/contracts/utils/Address.sol@v4.8.0


// OpenZeppelin Contracts (last updated v4.8.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
     * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
     *
     * _Available since v4.8._
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                // only check isContract if the call was successful and the return data is empty
                // otherwise we already know that it was a contract
                require(isContract(target), "Address: call to non-contract");
            }
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    /**
     * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason or using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    function _revert(bytes memory returndata, string memory errorMessage) private pure {
        // Look for revert reason and bubble it up if present
        if (returndata.length > 0) {
            // The easiest way to bubble the revert reason is using memory via assembly
            /// @solidity memory-safe-assembly
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert(errorMessage);
        }
    }
}


// File contracts/HyperlaneConnectionClient.sol


pragma solidity >=0.6.11;

// ============ Internal Imports ============



// ============ External Imports ============


abstract contract HyperlaneConnectionClient is
    OwnableUpgradeable,
    ISpecifiesInterchainSecurityModule
{
    // ============ Mutable Storage ============

    IMailbox public mailbox;
    // Interchain Gas Paymaster contract. The relayer associated with this contract
    // must be willing to relay messages dispatched from the current Mailbox contract,
    // otherwise payments made to the paymaster will not result in relayed messages.
    IInterchainGasPaymaster public interchainGasPaymaster;

    IInterchainSecurityModule public interchainSecurityModule;

    uint256[48] private __GAP; // gap for upgrade safety

    // ============ Events ============
    /**
     * @notice Emitted when a new mailbox is set.
     * @param mailbox The address of the mailbox contract
     */
    event MailboxSet(address indexed mailbox);

    /**
     * @notice Emitted when a new Interchain Gas Paymaster is set.
     * @param interchainGasPaymaster The address of the Interchain Gas Paymaster.
     */
    event InterchainGasPaymasterSet(address indexed interchainGasPaymaster);

    event InterchainSecurityModuleSet(address indexed module);

    // ============ Modifiers ============

    /**
     * @notice Only accept messages from an Hyperlane Mailbox contract
     */
    modifier onlyMailbox() {
        require(msg.sender == address(mailbox), "!mailbox");
        _;
    }

    /**
     * @notice Only accept addresses that at least have contract code
     */
    modifier onlyContract(address _contract) {
        require(Address.isContract(_contract), "!contract");
        _;
    }

    // ======== Initializer =========

    function __HyperlaneConnectionClient_initialize(address _mailbox)
        internal
        onlyInitializing
    {
        _setMailbox(_mailbox);
        __Ownable_init();
    }

    function __HyperlaneConnectionClient_initialize(
        address _mailbox,
        address _interchainGasPaymaster
    ) internal onlyInitializing {
        _setInterchainGasPaymaster(_interchainGasPaymaster);
        __HyperlaneConnectionClient_initialize(_mailbox);
    }

    function __HyperlaneConnectionClient_initialize(
        address _mailbox,
        address _interchainGasPaymaster,
        address _interchainSecurityModule
    ) internal onlyInitializing {
        _setInterchainSecurityModule(_interchainSecurityModule);
        __HyperlaneConnectionClient_initialize(
            _mailbox,
            _interchainGasPaymaster
        );
    }

    // ============ External functions ============

    /**
     * @notice Sets the address of the application's Mailbox.
     * @param _mailbox The address of the Mailbox contract.
     */
    function setMailbox(address _mailbox) external virtual onlyOwner {
        _setMailbox(_mailbox);
    }

    /**
     * @notice Sets the address of the application's InterchainGasPaymaster.
     * @param _interchainGasPaymaster The address of the InterchainGasPaymaster contract.
     */
    function setInterchainGasPaymaster(address _interchainGasPaymaster)
        external
        virtual
        onlyOwner
    {
        _setInterchainGasPaymaster(_interchainGasPaymaster);
    }

    function setInterchainSecurityModule(address _module)
        external
        virtual
        onlyOwner
    {
        _setInterchainSecurityModule(_module);
    }

    // ============ Internal functions ============

    /**
     * @notice Sets the address of the application's InterchainGasPaymaster.
     * @param _interchainGasPaymaster The address of the InterchainGasPaymaster contract.
     */
    function _setInterchainGasPaymaster(address _interchainGasPaymaster)
        internal
        onlyContract(_interchainGasPaymaster)
    {
        interchainGasPaymaster = IInterchainGasPaymaster(
            _interchainGasPaymaster
        );
        emit InterchainGasPaymasterSet(_interchainGasPaymaster);
    }

    /**
     * @notice Modify the contract the Application uses to validate Mailbox contracts
     * @param _mailbox The address of the mailbox contract
     */
    function _setMailbox(address _mailbox) internal onlyContract(_mailbox) {
        mailbox = IMailbox(_mailbox);
        emit MailboxSet(_mailbox);
    }

    function _setInterchainSecurityModule(address _module)
        internal
        onlyContract(_module)
    {
        interchainSecurityModule = IInterchainSecurityModule(_module);
        emit InterchainSecurityModuleSet(_module);
    }
}


// File contracts/InterchainGasPaymaster.sol


pragma solidity >=0.8.0;

// ============ Internal Imports ============

// ============ External Imports ============

/**
 * @title InterchainGasPaymaster
 * @notice Manages payments on a source chain to cover gas costs of relaying
 * messages to destination chains.
 */
contract InterchainGasPaymaster is IInterchainGasPaymaster, OwnableUpgradeable {
    // ============ Events ============

    /**
     * @notice Emitted when a payment is made for a message's gas costs.
     * @param messageId The ID of the message to pay for.
     * @param gasAmount The amount of destination gas paid for.
     * @param payment The amount of native tokens paid.
     */
    event GasPayment(
        bytes32 indexed messageId,
        uint256 gasAmount,
        uint256 payment
    );

    // ============ Constructor ============

    // solhint-disable-next-line no-empty-blocks
    constructor() {
        initialize(); // allows contract to be used without proxying
    }

    // ============ External Functions ============

    function initialize() public initializer {
        __Ownable_init();
    }

    /**
     * @notice Deposits msg.value as a payment for the relaying of a message
     * to its destination chain.
     * @param _messageId The ID of the message to pay for.
     * @param _destinationDomain The domain of the message's destination chain.
     * @param _gasAmount The amount of destination gas to pay for. Currently unused.
     * @param _refundAddress The address to refund any overpayment to. Currently unused.
     */
    function payForGas(
        bytes32 _messageId,
        uint32 _destinationDomain,
        uint256 _gasAmount,
        address _refundAddress
    ) external payable override {
        // Silence compiler warning. The NatSpec @param requires the parameter to be named.
        // While not used at the moment, future versions of the paymaster have behavior specific
        // to the destination domain and refund overpayments to the _refundAddress.
        _destinationDomain;
        _refundAddress;

        emit GasPayment(_messageId, _gasAmount, msg.value);
    }

    /**
     * @notice Transfers the entire native token balance to the owner of the contract.
     * @dev The owner must be able to receive native tokens.
     */
    function claim() external {
        // Transfer the entire balance to owner.
        (bool success, ) = owner().call{value: address(this).balance}("");
        require(success, "!transfer");
    }
}


// File @openzeppelin/contracts/utils/Context.sol@v4.8.0


// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}


// File @openzeppelin/contracts/access/Ownable.sol@v4.8.0


// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}


// File @openzeppelin/contracts/utils/math/Math.sol@v4.8.0


// OpenZeppelin Contracts (last updated v4.8.0) (utils/math/Math.sol)

pragma solidity ^0.8.0;

/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
    enum Rounding {
        Down, // Toward negative infinity
        Up, // Toward infinity
        Zero // Toward zero
    }

    /**
     * @dev Returns the largest of two numbers.
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a > b ? a : b;
    }

    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow.
        return (a & b) + (a ^ b) / 2;
    }

    /**
     * @dev Returns the ceiling of the division of two numbers.
     *
     * This differs from standard division with `/` in that it rounds up instead
     * of rounding down.
     */
    function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b - 1) / b can overflow on addition, so we distribute.
        return a == 0 ? 0 : (a - 1) / b + 1;
    }

    /**
     * @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
     * @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv)
     * with further edits by Uniswap Labs also under MIT license.
     */
    function mulDiv(
        uint256 x,
        uint256 y,
        uint256 denominator
    ) internal pure returns (uint256 result) {
        unchecked {
            // 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
            // use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
            // variables such that product = prod1 * 2^256 + prod0.
            uint256 prod0; // Least significant 256 bits of the product
            uint256 prod1; // Most significant 256 bits of the product
            assembly {
                let mm := mulmod(x, y, not(0))
                prod0 := mul(x, y)
                prod1 := sub(sub(mm, prod0), lt(mm, prod0))
            }

            // Handle non-overflow cases, 256 by 256 division.
            if (prod1 == 0) {
                return prod0 / denominator;
            }

            // Make sure the result is less than 2^256. Also prevents denominator == 0.
            require(denominator > prod1);

            ///////////////////////////////////////////////
            // 512 by 256 division.
            ///////////////////////////////////////////////

            // Make division exact by subtracting the remainder from [prod1 prod0].
            uint256 remainder;
            assembly {
                // Compute remainder using mulmod.
                remainder := mulmod(x, y, denominator)

                // Subtract 256 bit number from 512 bit number.
                prod1 := sub(prod1, gt(remainder, prod0))
                prod0 := sub(prod0, remainder)
            }

            // Factor powers of two out of denominator and compute largest power of two divisor of denominator. Always >= 1.
            // See https://cs.stackexchange.com/q/138556/92363.

            // Does not overflow because the denominator cannot be zero at this stage in the function.
            uint256 twos = denominator & (~denominator + 1);
            assembly {
                // Divide denominator by twos.
                denominator := div(denominator, twos)

                // Divide [prod1 prod0] by twos.
                prod0 := div(prod0, twos)

                // Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
                twos := add(div(sub(0, twos), twos), 1)
            }

            // Shift in bits from prod1 into prod0.
            prod0 |= prod1 * twos;

            // Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such
            // that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for
            // four bits. That is, denominator * inv = 1 mod 2^4.
            uint256 inverse = (3 * denominator) ^ 2;

            // Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also works
            // in modular arithmetic, doubling the correct bits in each step.
            inverse *= 2 - denominator * inverse; // inverse mod 2^8
            inverse *= 2 - denominator * inverse; // inverse mod 2^16
            inverse *= 2 - denominator * inverse; // inverse mod 2^32
            inverse *= 2 - denominator * inverse; // inverse mod 2^64
            inverse *= 2 - denominator * inverse; // inverse mod 2^128
            inverse *= 2 - denominator * inverse; // inverse mod 2^256

            // Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
            // This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is
            // less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1
            // is no longer required.
            result = prod0 * inverse;
            return result;
        }
    }

    /**
     * @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
     */
    function mulDiv(
        uint256 x,
        uint256 y,
        uint256 denominator,
        Rounding rounding
    ) internal pure returns (uint256) {
        uint256 result = mulDiv(x, y, denominator);
        if (rounding == Rounding.Up && mulmod(x, y, denominator) > 0) {
            result += 1;
        }
        return result;
    }

    /**
     * @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded down.
     *
     * Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
     */
    function sqrt(uint256 a) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }

        // For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.
        //
        // We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have
        // `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.
        //
        // This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`
        // → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`
        // → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`
        //
        // Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.
        uint256 result = 1 << (log2(a) >> 1);

        // At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,
        // since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at
        // every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision
        // into the expected uint128 result.
        unchecked {
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            return min(result, a / result);
        }
    }

    /**
     * @notice Calculates sqrt(a), following the selected rounding direction.
     */
    function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = sqrt(a);
            return result + (rounding == Rounding.Up && result * result < a ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 2, rounded down, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 128;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 64;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 32;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 16;
            }
            if (value >> 8 > 0) {
                value >>= 8;
                result += 8;
            }
            if (value >> 4 > 0) {
                value >>= 4;
                result += 4;
            }
            if (value >> 2 > 0) {
                value >>= 2;
                result += 2;
            }
            if (value >> 1 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 2, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log2(value);
            return result + (rounding == Rounding.Up && 1 << result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 10, rounded down, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >= 10**64) {
                value /= 10**64;
                result += 64;
            }
            if (value >= 10**32) {
                value /= 10**32;
                result += 32;
            }
            if (value >= 10**16) {
                value /= 10**16;
                result += 16;
            }
            if (value >= 10**8) {
                value /= 10**8;
                result += 8;
            }
            if (value >= 10**4) {
                value /= 10**4;
                result += 4;
            }
            if (value >= 10**2) {
                value /= 10**2;
                result += 2;
            }
            if (value >= 10**1) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log10(value);
            return result + (rounding == Rounding.Up && 10**result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 256, rounded down, of a positive value.
     * Returns 0 if given 0.
     *
     * Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.
     */
    function log256(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 16;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 8;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 4;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 2;
            }
            if (value >> 8 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log256(value);
            return result + (rounding == Rounding.Up && 1 << (result * 8) < value ? 1 : 0);
        }
    }
}


// File @openzeppelin/contracts/utils/Strings.sol@v4.8.0


// OpenZeppelin Contracts (last updated v4.8.0) (utils/Strings.sol)

pragma solidity ^0.8.0;

/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant _SYMBOLS = "0123456789abcdef";
    uint8 private constant _ADDRESS_LENGTH = 20;

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        unchecked {
            uint256 length = Math.log10(value) + 1;
            string memory buffer = new string(length);
            uint256 ptr;
            /// @solidity memory-safe-assembly
            assembly {
                ptr := add(buffer, add(32, length))
            }
            while (true) {
                ptr--;
                /// @solidity memory-safe-assembly
                assembly {
                    mstore8(ptr, byte(mod(value, 10), _SYMBOLS))
                }
                value /= 10;
                if (value == 0) break;
            }
            return buffer;
        }
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        unchecked {
            return toHexString(value, Math.log256(value) + 1);
        }
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = _SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }

    /**
     * @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal representation.
     */
    function toHexString(address addr) internal pure returns (string memory) {
        return toHexString(uint256(uint160(addr)), _ADDRESS_LENGTH);
    }
}


// File @openzeppelin/contracts/utils/cryptography/ECDSA.sol@v4.8.0


// OpenZeppelin Contracts (last updated v4.8.0) (utils/cryptography/ECDSA.sol)

pragma solidity ^0.8.0;

/**
 * @dev Elliptic Curve Digital Signature Algorithm (ECDSA) operations.
 *
 * These functions can be used to verify that a message was signed by the holder
 * of the private keys of a given address.
 */
library ECDSA {
    enum RecoverError {
        NoError,
        InvalidSignature,
        InvalidSignatureLength,
        InvalidSignatureS,
        InvalidSignatureV // Deprecated in v4.8
    }

    function _throwError(RecoverError error) private pure {
        if (error == RecoverError.NoError) {
            return; // no error: do nothing
        } else if (error == RecoverError.InvalidSignature) {
            revert("ECDSA: invalid signature");
        } else if (error == RecoverError.InvalidSignatureLength) {
            revert("ECDSA: invalid signature length");
        } else if (error == RecoverError.InvalidSignatureS) {
            revert("ECDSA: invalid signature 's' value");
        }
    }

    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature` or error string. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise
     * be too long), and then calling {toEthSignedMessageHash} on it.
     *
     * Documentation for signature generation:
     * - with https://web3js.readthedocs.io/en/v1.3.4/web3-eth-accounts.html#sign[Web3.js]
     * - with https://docs.ethers.io/v5/api/signer/#Signer-signMessage[ethers]
     *
     * _Available since v4.3._
     */
    function tryRecover(bytes32 hash, bytes memory signature) internal pure returns (address, RecoverError) {
        if (signature.length == 65) {
            bytes32 r;
            bytes32 s;
            uint8 v;
            // ecrecover takes the signature parameters, and the only way to get them
            // currently is to use assembly.
            /// @solidity memory-safe-assembly
            assembly {
                r := mload(add(signature, 0x20))
                s := mload(add(signature, 0x40))
                v := byte(0, mload(add(signature, 0x60)))
            }
            return tryRecover(hash, v, r, s);
        } else {
            return (address(0), RecoverError.InvalidSignatureLength);
        }
    }

    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature`. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise
     * be too long), and then calling {toEthSignedMessageHash} on it.
     */
    function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, signature);
        _throwError(error);
        return recovered;
    }

    /**
     * @dev Overload of {ECDSA-tryRecover} that receives the `r` and `vs` short-signature fields separately.
     *
     * See https://eips.ethereum.org/EIPS/eip-2098[EIP-2098 short signatures]
     *
     * _Available since v4.3._
     */
    function tryRecover(
        bytes32 hash,
        bytes32 r,
        bytes32 vs
    ) internal pure returns (address, RecoverError) {
        bytes32 s = vs & bytes32(0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff);
        uint8 v = uint8((uint256(vs) >> 255) + 27);
        return tryRecover(hash, v, r, s);
    }

    /**
     * @dev Overload of {ECDSA-recover} that receives the `r and `vs` short-signature fields separately.
     *
     * _Available since v4.2._
     */
    function recover(
        bytes32 hash,
        bytes32 r,
        bytes32 vs
    ) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, r, vs);
        _throwError(error);
        return recovered;
    }

    /**
     * @dev Overload of {ECDSA-tryRecover} that receives the `v`,
     * `r` and `s` signature fields separately.
     *
     * _Available since v4.3._
     */
    function tryRecover(
        bytes32 hash,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal pure returns (address, RecoverError) {
        // EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
        // unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
        // the valid range for s in (301): 0 < s < secp256k1n ÷ 2 + 1, and for v in (302): v ∈ {27, 28}. Most
        // signatures from current libraries generate a unique signature with an s-value in the lower half order.
        //
        // If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
        // with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
        // vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
        // these malleable signatures as well.
        if (uint256(s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {
            return (address(0), RecoverError.InvalidSignatureS);
        }

        // If the signature is valid (and not malleable), return the signer address
        address signer = ecrecover(hash, v, r, s);
        if (signer == address(0)) {
            return (address(0), RecoverError.InvalidSignature);
        }

        return (signer, RecoverError.NoError);
    }

    /**
     * @dev Overload of {ECDSA-recover} that receives the `v`,
     * `r` and `s` signature fields separately.
     */
    function recover(
        bytes32 hash,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, v, r, s);
        _throwError(error);
        return recovered;
    }

    /**
     * @dev Returns an Ethereum Signed Message, created from a `hash`. This
     * produces hash corresponding to the one signed with the
     * https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
     * JSON-RPC method as part of EIP-191.
     *
     * See {recover}.
     */
    function toEthSignedMessageHash(bytes32 hash) internal pure returns (bytes32) {
        // 32 is the length in bytes of hash,
        // enforced by the type signature above
        return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", hash));
    }

    /**
     * @dev Returns an Ethereum Signed Message, created from `s`. This
     * produces hash corresponding to the one signed with the
     * https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
     * JSON-RPC method as part of EIP-191.
     *
     * See {recover}.
     */
    function toEthSignedMessageHash(bytes memory s) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n", Strings.toString(s.length), s));
    }

    /**
     * @dev Returns an Ethereum Signed Typed Data, created from a
     * `domainSeparator` and a `structHash`. This produces hash corresponding
     * to the one signed with the
     * https://eips.ethereum.org/EIPS/eip-712[`eth_signTypedData`]
     * JSON-RPC method as part of EIP-712.
     *
     * See {recover}.
     */
    function toTypedDataHash(bytes32 domainSeparator, bytes32 structHash) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked("\x19\x01", domainSeparator, structHash));
    }
}


// File @openzeppelin/contracts/utils/structs/EnumerableSet.sol@v4.8.0


// OpenZeppelin Contracts (last updated v4.8.0) (utils/structs/EnumerableSet.sol)
// This file was procedurally generated from scripts/generate/templates/EnumerableSet.js.

pragma solidity ^0.8.0;

/**
 * @dev Library for managing
 * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
 * types.
 *
 * Sets have the following properties:
 *
 * - Elements are added, removed, and checked for existence in constant time
 * (O(1)).
 * - Elements are enumerated in O(n). No guarantees are made on the ordering.
 *
 * ```
 * contract Example {
 *     // Add the library methods
 *     using EnumerableSet for EnumerableSet.AddressSet;
 *
 *     // Declare a set state variable
 *     EnumerableSet.AddressSet private mySet;
 * }
 * ```
 *
 * As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`)
 * and `uint256` (`UintSet`) are supported.
 *
 * [WARNING]
 * ====
 * Trying to delete such a structure from storage will likely result in data corruption, rendering the structure
 * unusable.
 * See https://github.com/ethereum/solidity/pull/11843[ethereum/solidity#11843] for more info.
 *
 * In order to clean an EnumerableSet, you can either remove all elements one by one or create a fresh instance using an
 * array of EnumerableSet.
 * ====
 */
library EnumerableSet {
    // To implement this library for multiple types with as little code
    // repetition as possible, we write it in terms of a generic Set type with
    // bytes32 values.
    // The Set implementation uses private functions, and user-facing
    // implementations (such as AddressSet) are just wrappers around the
    // underlying Set.
    // This means that we can only create new EnumerableSets for types that fit
    // in bytes32.

    struct Set {
        // Storage of set values
        bytes32[] _values;
        // Position of the value in the `values` array, plus 1 because index 0
        // means a value is not in the set.
        mapping(bytes32 => uint256) _indexes;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function _add(Set storage set, bytes32 value) private returns (bool) {
        if (!_contains(set, value)) {
            set._values.push(value);
            // The value is stored at length-1, but we add 1 to all indexes
            // and use 0 as a sentinel value
            set._indexes[value] = set._values.length;
            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function _remove(Set storage set, bytes32 value) private returns (bool) {
        // We read and store the value's index to prevent multiple reads from the same storage slot
        uint256 valueIndex = set._indexes[value];

        if (valueIndex != 0) {
            // Equivalent to contains(set, value)
            // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
            // the array, and then remove the last element (sometimes called as 'swap and pop').
            // This modifies the order of the array, as noted in {at}.

            uint256 toDeleteIndex = valueIndex - 1;
            uint256 lastIndex = set._values.length - 1;

            if (lastIndex != toDeleteIndex) {
                bytes32 lastValue = set._values[lastIndex];

                // Move the last value to the index where the value to delete is
                set._values[toDeleteIndex] = lastValue;
                // Update the index for the moved value
                set._indexes[lastValue] = valueIndex; // Replace lastValue's index to valueIndex
            }

            // Delete the slot where the moved value was stored
            set._values.pop();

            // Delete the index for the deleted slot
            delete set._indexes[value];

            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function _contains(Set storage set, bytes32 value) private view returns (bool) {
        return set._indexes[value] != 0;
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function _length(Set storage set) private view returns (uint256) {
        return set._values.length;
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function _at(Set storage set, uint256 index) private view returns (bytes32) {
        return set._values[index];
    }

    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function _values(Set storage set) private view returns (bytes32[] memory) {
        return set._values;
    }

    // Bytes32Set

    struct Bytes32Set {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _add(set._inner, value);
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _remove(set._inner, value);
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(Bytes32Set storage set, bytes32 value) internal view returns (bool) {
        return _contains(set._inner, value);
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(Bytes32Set storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(Bytes32Set storage set, uint256 index) internal view returns (bytes32) {
        return _at(set._inner, index);
    }

    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function values(Bytes32Set storage set) internal view returns (bytes32[] memory) {
        bytes32[] memory store = _values(set._inner);
        bytes32[] memory result;

        /// @solidity memory-safe-assembly
        assembly {
            result := store
        }

        return result;
    }

    // AddressSet

    struct AddressSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(AddressSet storage set, address value) internal returns (bool) {
        return _add(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(AddressSet storage set, address value) internal returns (bool) {
        return _remove(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(AddressSet storage set, address value) internal view returns (bool) {
        return _contains(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(AddressSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(AddressSet storage set, uint256 index) internal view returns (address) {
        return address(uint160(uint256(_at(set._inner, index))));
    }

    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function values(AddressSet storage set) internal view returns (address[] memory) {
        bytes32[] memory store = _values(set._inner);
        address[] memory result;

        /// @solidity memory-safe-assembly
        assembly {
            result := store
        }

        return result;
    }

    // UintSet

    struct UintSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(UintSet storage set, uint256 value) internal returns (bool) {
        return _add(set._inner, bytes32(value));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(UintSet storage set, uint256 value) internal returns (bool) {
        return _remove(set._inner, bytes32(value));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(UintSet storage set, uint256 value) internal view returns (bool) {
        return _contains(set._inner, bytes32(value));
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(UintSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(UintSet storage set, uint256 index) internal view returns (uint256) {
        return uint256(_at(set._inner, index));
    }

    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function values(UintSet storage set) internal view returns (uint256[] memory) {
        bytes32[] memory store = _values(set._inner);
        uint256[] memory result;

        /// @solidity memory-safe-assembly
        assembly {
            result := store
        }

        return result;
    }
}


// File interfaces/IMultisigIsm.sol


pragma solidity >=0.6.0;

interface IMultisigIsm is IInterchainSecurityModule {
    /**
     * @notice Returns the set of validators responsible for verifying _message
     * and the number of signatures required
     * @dev Can change based on the content of _message
     * @param _message Hyperlane formatted interchain message
     * @return validators The array of validator addresses
     * @return threshold The number of validator signatures needed
     */
    function validatorsAndThreshold(bytes calldata _message)
        external
        view
        returns (address[] memory validators, uint8 threshold);
}


// File contracts/libs/TypeCasts.sol


pragma solidity >=0.6.11;

library TypeCasts {
    // treat it as a null-terminated string of max 32 bytes
    function coerceString(bytes32 _buf)
        internal
        pure
        returns (string memory _newStr)
    {
        uint8 _slen = 0;
        while (_slen < 32 && _buf[_slen] != 0) {
            _slen++;
        }

        // solhint-disable-next-line no-inline-assembly
        assembly {
            _newStr := mload(0x40)
            mstore(0x40, add(_newStr, 0x40)) // may end up with extra
            mstore(_newStr, _slen)
            mstore(add(_newStr, 0x20), _buf)
        }
    }

    // alignment preserving cast
    function addressToBytes32(address _addr) internal pure returns (bytes32) {
        return bytes32(uint256(uint160(_addr)));
    }

    // alignment preserving cast
    function bytes32ToAddress(bytes32 _buf) internal pure returns (address) {
        return address(uint160(uint256(_buf)));
    }
}


// File contracts/libs/Message.sol


pragma solidity >=0.8.0;

/**
 * @title Hyperlane Message Library
 * @notice Library for formatted messages used by Mailbox
 **/
library Message {
    using TypeCasts for bytes32;

    uint256 private constant VERSION_OFFSET = 0;
    uint256 private constant NONCE_OFFSET = 1;
    uint256 private constant ORIGIN_OFFSET = 5;
    uint256 private constant SENDER_OFFSET = 9;
    uint256 private constant DESTINATION_OFFSET = 41;
    uint256 private constant RECIPIENT_OFFSET = 45;
    uint256 private constant BODY_OFFSET = 77;

    /**
     * @notice Returns formatted (packed) Hyperlane message with provided fields
     * @dev This function should only be used in memory message construction.
     * @param _version The version of the origin and destination Mailboxes
     * @param _nonce A nonce to uniquely identify the message on its origin chain
     * @param _originDomain Domain of origin chain
     * @param _sender Address of sender as bytes32
     * @param _destinationDomain Domain of destination chain
     * @param _recipient Address of recipient on destination chain as bytes32
     * @param _messageBody Raw bytes of message body
     * @return Formatted message
     */
    function formatMessage(
        uint8 _version,
        uint32 _nonce,
        uint32 _originDomain,
        bytes32 _sender,
        uint32 _destinationDomain,
        bytes32 _recipient,
        bytes calldata _messageBody
    ) internal pure returns (bytes memory) {
        return
            abi.encodePacked(
                _version,
                _nonce,
                _originDomain,
                _sender,
                _destinationDomain,
                _recipient,
                _messageBody
            );
    }

    /**
     * @notice Returns the message ID.
     * @param _message ABI encoded Hyperlane message.
     * @return ID of `_message`
     */
    function id(bytes memory _message) internal pure returns (bytes32) {
        return keccak256(_message);
    }

    /**
     * @notice Returns the message version.
     * @param _message ABI encoded Hyperlane message.
     * @return Version of `_message`
     */
    function version(bytes calldata _message) internal pure returns (uint8) {
        return uint8(bytes1(_message[VERSION_OFFSET:NONCE_OFFSET]));
    }

    /**
     * @notice Returns the message nonce.
     * @param _message ABI encoded Hyperlane message.
     * @return Nonce of `_message`
     */
    function nonce(bytes calldata _message) internal pure returns (uint32) {
        return uint32(bytes4(_message[NONCE_OFFSET:ORIGIN_OFFSET]));
    }

    /**
     * @notice Returns the message origin domain.
     * @param _message ABI encoded Hyperlane message.
     * @return Origin domain of `_message`
     */
    function origin(bytes calldata _message) internal pure returns (uint32) {
        return uint32(bytes4(_message[ORIGIN_OFFSET:SENDER_OFFSET]));
    }

    /**
     * @notice Returns the message sender as bytes32.
     * @param _message ABI encoded Hyperlane message.
     * @return Sender of `_message` as bytes32
     */
    function sender(bytes calldata _message) internal pure returns (bytes32) {
        return bytes32(_message[SENDER_OFFSET:DESTINATION_OFFSET]);
    }

    /**
     * @notice Returns the message sender as address.
     * @param _message ABI encoded Hyperlane message.
     * @return Sender of `_message` as address
     */
    function senderAddress(bytes calldata _message)
        internal
        pure
        returns (address)
    {
        return sender(_message).bytes32ToAddress();
    }

    /**
     * @notice Returns the message destination domain.
     * @param _message ABI encoded Hyperlane message.
     * @return Destination domain of `_message`
     */
    function destination(bytes calldata _message)
        internal
        pure
        returns (uint32)
    {
        return uint32(bytes4(_message[DESTINATION_OFFSET:RECIPIENT_OFFSET]));
    }

    /**
     * @notice Returns the message recipient as bytes32.
     * @param _message ABI encoded Hyperlane message.
     * @return Recipient of `_message` as bytes32
     */
    function recipient(bytes calldata _message)
        internal
        pure
        returns (bytes32)
    {
        return bytes32(_message[RECIPIENT_OFFSET:BODY_OFFSET]);
    }

    /**
     * @notice Returns the message recipient as address.
     * @param _message ABI encoded Hyperlane message.
     * @return Recipient of `_message` as address
     */
    function recipientAddress(bytes calldata _message)
        internal
        pure
        returns (address)
    {
        return recipient(_message).bytes32ToAddress();
    }

    /**
     * @notice Returns the message body.
     * @param _message ABI encoded Hyperlane message.
     * @return Body of `_message`
     */
    function body(bytes calldata _message)
        internal
        pure
        returns (bytes calldata)
    {
        return bytes(_message[BODY_OFFSET:]);
    }
}


// File contracts/libs/MultisigIsmMetadata.sol


pragma solidity >=0.8.0;

/**
 * Format of metadata:
 * [   0:  32] Merkle root
 * [  32:  36] Root index
 * [  36:  68] Origin mailbox address
 * [  68:1092] Merkle proof
 * [1092:1093] Threshold
 * [1093:????] Validator signatures, 65 bytes each, length == Threshold
 * [????:????] Addresses of the entire validator set, left padded to bytes32
 */
library MultisigIsmMetadata {
    uint256 private constant MERKLE_ROOT_OFFSET = 0;
    uint256 private constant MERKLE_INDEX_OFFSET = 32;
    uint256 private constant ORIGIN_MAILBOX_OFFSET = 36;
    uint256 private constant MERKLE_PROOF_OFFSET = 68;
    uint256 private constant THRESHOLD_OFFSET = 1092;
    uint256 private constant SIGNATURES_OFFSET = 1093;
    uint256 private constant SIGNATURE_LENGTH = 65;

    /**
     * @notice Returns the merkle root of the signed checkpoint.
     * @param _metadata ABI encoded Multisig ISM metadata.
     * @return Merkle root of the signed checkpoint
     */
    function root(bytes calldata _metadata) internal pure returns (bytes32) {
        return bytes32(_metadata[MERKLE_ROOT_OFFSET:MERKLE_INDEX_OFFSET]);
    }

    /**
     * @notice Returns the index of the signed checkpoint.
     * @param _metadata ABI encoded Multisig ISM metadata.
     * @return Index of the signed checkpoint
     */
    function index(bytes calldata _metadata) internal pure returns (uint32) {
        return
            uint32(
                bytes4(_metadata[MERKLE_INDEX_OFFSET:ORIGIN_MAILBOX_OFFSET])
            );
    }

    /**
     * @notice Returns the origin mailbox of the signed checkpoint as bytes32.
     * @param _metadata ABI encoded Multisig ISM metadata.
     * @return Origin mailbox of the signed checkpoint as bytes32
     */
    function originMailbox(bytes calldata _metadata)
        internal
        pure
        returns (bytes32)
    {
        return bytes32(_metadata[ORIGIN_MAILBOX_OFFSET:MERKLE_PROOF_OFFSET]);
    }

    /**
     * @notice Returns the merkle proof branch of the message.
     * @dev This appears to be more gas efficient than returning a calldata
     * slice and using that.
     * @param _metadata ABI encoded Multisig ISM metadata.
     * @return Merkle proof branch of the message.
     */
    function proof(bytes calldata _metadata)
        internal
        pure
        returns (bytes32[32] memory)
    {
        return
            abi.decode(
                _metadata[MERKLE_PROOF_OFFSET:THRESHOLD_OFFSET],
                (bytes32[32])
            );
    }

    /**
     * @notice Returns the number of required signatures. Verified against
     * the commitment stored in the module.
     * @param _metadata ABI encoded Multisig ISM metadata.
     * @return The number of required signatures.
     */
    function threshold(bytes calldata _metadata) internal pure returns (uint8) {
        return uint8(bytes1(_metadata[THRESHOLD_OFFSET:SIGNATURES_OFFSET]));
    }

    /**
     * @notice Returns the validator ECDSA signature at `_index`.
     * @dev Assumes signatures are sorted by validator
     * @dev Assumes `_metadata` encodes `threshold` signatures.
     * @dev Assumes `_index` is less than `threshold`
     * @param _metadata ABI encoded Multisig ISM metadata.
     * @param _index The index of the signature to return.
     * @return The validator ECDSA signature at `_index`.
     */
    function signatureAt(bytes calldata _metadata, uint256 _index)
        internal
        pure
        returns (bytes calldata)
    {
        uint256 _start = SIGNATURES_OFFSET + (_index * SIGNATURE_LENGTH);
        uint256 _end = _start + SIGNATURE_LENGTH;
        return _metadata[_start:_end];
    }

    /**
     * @notice Returns the validator address at `_index`.
     * @dev Assumes `_index` is less than the number of validators
     * @param _metadata ABI encoded Multisig ISM metadata.
     * @param _index The index of the validator to return.
     * @return The validator address at `_index`.
     */
    function validatorAt(bytes calldata _metadata, uint256 _index)
        internal
        pure
        returns (address)
    {
        // Validator addresses are left padded to bytes32 in order to match
        // abi.encodePacked(address[]).
        uint256 _start = _validatorsOffset(_metadata) + (_index * 32) + 12;
        uint256 _end = _start + 20;
        return address(bytes20(_metadata[_start:_end]));
    }

    /**
     * @notice Returns the validator set encoded as bytes. Verified against the
     * commitment stored in the module.
     * @dev Validator addresses are encoded as tightly packed array of bytes32,
     * sorted to match the enumerable set stored by the module.
     * @param _metadata ABI encoded Multisig ISM metadata.
     * @return The validator set encoded as bytes.
     */
    function validators(bytes calldata _metadata)
        internal
        pure
        returns (bytes calldata)
    {
        return _metadata[_validatorsOffset(_metadata):];
    }

    /**
     * @notice Returns the size of the validator set encoded in the metadata
     * @dev Validator addresses are encoded as tightly packed array of bytes32,
     * sorted to match the enumerable set stored by the module.
     * @param _metadata ABI encoded Multisig ISM metadata.
     * @return The size of the validator set encoded in the metadata
     */
    function commitment(bytes calldata _metadata)
        internal
        pure
        returns (uint256)
    {
        return (_metadata.length - _validatorsOffset(_metadata)) / 32;
    }

    /**
     * @notice Returns the size of the validator set encoded in the metadata
     * @dev Validator addresses are encoded as tightly packed array of bytes32,
     * sorted to match the enumerable set stored by the module.
     * @param _metadata ABI encoded Multisig ISM metadata.
     * @return The size of the validator set encoded in the metadata
     */
    function validatorCount(bytes calldata _metadata)
        internal
        pure
        returns (uint256)
    {
        return (_metadata.length - _validatorsOffset(_metadata)) / 32;
    }

    /**
     * @notice Returns the offset in bytes of the list of validators within
     * `_metadata`.
     * @param _metadata ABI encoded Multisig ISM metadata.
     * @return The index at which the list of validators starts
     */
    function _validatorsOffset(bytes calldata _metadata)
        private
        pure
        returns (uint256)
    {
        return
            SIGNATURES_OFFSET +
            (uint256(threshold(_metadata)) * SIGNATURE_LENGTH);
    }
}


// File contracts/libs/Merkle.sol


pragma solidity >=0.6.11;

// work based on eth2 deposit contract, which is used under CC0-1.0

/**
 * @title MerkleLib
 * @author Celo Labs Inc.
 * @notice An incremental merkle tree modeled on the eth2 deposit contract.
 **/
library MerkleLib {
    uint256 internal constant TREE_DEPTH = 32;
    uint256 internal constant MAX_LEAVES = 2**TREE_DEPTH - 1;

    /**
     * @notice Struct representing incremental merkle tree. Contains current
     * branch and the number of inserted leaves in the tree.
     **/
    struct Tree {
        bytes32[TREE_DEPTH] branch;
        uint256 count;
    }

    /**
     * @notice Inserts `_node` into merkle tree
     * @dev Reverts if tree is full
     * @param _node Element to insert into tree
     **/
    function insert(Tree storage _tree, bytes32 _node) internal {
        require(_tree.count < MAX_LEAVES, "merkle tree full");

        _tree.count += 1;
        uint256 size = _tree.count;
        for (uint256 i = 0; i < TREE_DEPTH; i++) {
            if ((size & 1) == 1) {
                _tree.branch[i] = _node;
                return;
            }
            _node = keccak256(abi.encodePacked(_tree.branch[i], _node));
            size /= 2;
        }
        // As the loop should always end prematurely with the `return` statement,
        // this code should be unreachable. We assert `false` just to be safe.
        assert(false);
    }

    /**
     * @notice Calculates and returns`_tree`'s current root given array of zero
     * hashes
     * @param _zeroes Array of zero hashes
     * @return _current Calculated root of `_tree`
     **/
    function rootWithCtx(Tree storage _tree, bytes32[TREE_DEPTH] memory _zeroes)
        internal
        view
        returns (bytes32 _current)
    {
        uint256 _index = _tree.count;

        for (uint256 i = 0; i < TREE_DEPTH; i++) {
            uint256 _ithBit = (_index >> i) & 0x01;
            bytes32 _next = _tree.branch[i];
            if (_ithBit == 1) {
                _current = keccak256(abi.encodePacked(_next, _current));
            } else {
                _current = keccak256(abi.encodePacked(_current, _zeroes[i]));
            }
        }
    }

    /// @notice Calculates and returns`_tree`'s current root
    function root(Tree storage _tree) internal view returns (bytes32) {
        return rootWithCtx(_tree, zeroHashes());
    }

    /// @notice Returns array of TREE_DEPTH zero hashes
    /// @return _zeroes Array of TREE_DEPTH zero hashes
    function zeroHashes()
        internal
        pure
        returns (bytes32[TREE_DEPTH] memory _zeroes)
    {
        _zeroes[0] = Z_0;
        _zeroes[1] = Z_1;
        _zeroes[2] = Z_2;
        _zeroes[3] = Z_3;
        _zeroes[4] = Z_4;
        _zeroes[5] = Z_5;
        _zeroes[6] = Z_6;
        _zeroes[7] = Z_7;
        _zeroes[8] = Z_8;
        _zeroes[9] = Z_9;
        _zeroes[10] = Z_10;
        _zeroes[11] = Z_11;
        _zeroes[12] = Z_12;
        _zeroes[13] = Z_13;
        _zeroes[14] = Z_14;
        _zeroes[15] = Z_15;
        _zeroes[16] = Z_16;
        _zeroes[17] = Z_17;
        _zeroes[18] = Z_18;
        _zeroes[19] = Z_19;
        _zeroes[20] = Z_20;
        _zeroes[21] = Z_21;
        _zeroes[22] = Z_22;
        _zeroes[23] = Z_23;
        _zeroes[24] = Z_24;
        _zeroes[25] = Z_25;
        _zeroes[26] = Z_26;
        _zeroes[27] = Z_27;
        _zeroes[28] = Z_28;
        _zeroes[29] = Z_29;
        _zeroes[30] = Z_30;
        _zeroes[31] = Z_31;
    }

    /**
     * @notice Calculates and returns the merkle root for the given leaf
     * `_item`, a merkle branch, and the index of `_item` in the tree.
     * @param _item Merkle leaf
     * @param _branch Merkle proof
     * @param _index Index of `_item` in tree
     * @return _current Calculated merkle root
     **/
    function branchRoot(
        bytes32 _item,
        bytes32[TREE_DEPTH] memory _branch,
        uint256 _index
    ) internal pure returns (bytes32 _current) {
        _current = _item;

        for (uint256 i = 0; i < TREE_DEPTH; i++) {
            uint256 _ithBit = (_index >> i) & 0x01;
            bytes32 _next = _branch[i];
            if (_ithBit == 1) {
                _current = keccak256(abi.encodePacked(_next, _current));
            } else {
                _current = keccak256(abi.encodePacked(_current, _next));
            }
        }
    }

    // keccak256 zero hashes
    bytes32 internal constant Z_0 =
        hex"0000000000000000000000000000000000000000000000000000000000000000";
    bytes32 internal constant Z_1 =
        hex"ad3228b676f7d3cd4284a5443f17f1962b36e491b30a40b2405849e597ba5fb5";
    bytes32 internal constant Z_2 =
        hex"b4c11951957c6f8f642c4af61cd6b24640fec6dc7fc607ee8206a99e92410d30";
    bytes32 internal constant Z_3 =
        hex"21ddb9a356815c3fac1026b6dec5df3124afbadb485c9ba5a3e3398a04b7ba85";
    bytes32 internal constant Z_4 =
        hex"e58769b32a1beaf1ea27375a44095a0d1fb664ce2dd358e7fcbfb78c26a19344";
    bytes32 internal constant Z_5 =
        hex"0eb01ebfc9ed27500cd4dfc979272d1f0913cc9f66540d7e8005811109e1cf2d";
    bytes32 internal constant Z_6 =
        hex"887c22bd8750d34016ac3c66b5ff102dacdd73f6b014e710b51e8022af9a1968";
    bytes32 internal constant Z_7 =
        hex"ffd70157e48063fc33c97a050f7f640233bf646cc98d9524c6b92bcf3ab56f83";
    bytes32 internal constant Z_8 =
        hex"9867cc5f7f196b93bae1e27e6320742445d290f2263827498b54fec539f756af";
    bytes32 internal constant Z_9 =
        hex"cefad4e508c098b9a7e1d8feb19955fb02ba9675585078710969d3440f5054e0";
    bytes32 internal constant Z_10 =
        hex"f9dc3e7fe016e050eff260334f18a5d4fe391d82092319f5964f2e2eb7c1c3a5";
    bytes32 internal constant Z_11 =
        hex"f8b13a49e282f609c317a833fb8d976d11517c571d1221a265d25af778ecf892";
    bytes32 internal constant Z_12 =
        hex"3490c6ceeb450aecdc82e28293031d10c7d73bf85e57bf041a97360aa2c5d99c";
    bytes32 internal constant Z_13 =
        hex"c1df82d9c4b87413eae2ef048f94b4d3554cea73d92b0f7af96e0271c691e2bb";
    bytes32 internal constant Z_14 =
        hex"5c67add7c6caf302256adedf7ab114da0acfe870d449a3a489f781d659e8becc";
    bytes32 internal constant Z_15 =
        hex"da7bce9f4e8618b6bd2f4132ce798cdc7a60e7e1460a7299e3c6342a579626d2";
    bytes32 internal constant Z_16 =
        hex"2733e50f526ec2fa19a22b31e8ed50f23cd1fdf94c9154ed3a7609a2f1ff981f";
    bytes32 internal constant Z_17 =
        hex"e1d3b5c807b281e4683cc6d6315cf95b9ade8641defcb32372f1c126e398ef7a";
    bytes32 internal constant Z_18 =
        hex"5a2dce0a8a7f68bb74560f8f71837c2c2ebbcbf7fffb42ae1896f13f7c7479a0";
    bytes32 internal constant Z_19 =
        hex"b46a28b6f55540f89444f63de0378e3d121be09e06cc9ded1c20e65876d36aa0";
    bytes32 internal constant Z_20 =
        hex"c65e9645644786b620e2dd2ad648ddfcbf4a7e5b1a3a4ecfe7f64667a3f0b7e2";
    bytes32 internal constant Z_21 =
        hex"f4418588ed35a2458cffeb39b93d26f18d2ab13bdce6aee58e7b99359ec2dfd9";
    bytes32 internal constant Z_22 =
        hex"5a9c16dc00d6ef18b7933a6f8dc65ccb55667138776f7dea101070dc8796e377";
    bytes32 internal constant Z_23 =
        hex"4df84f40ae0c8229d0d6069e5c8f39a7c299677a09d367fc7b05e3bc380ee652";
    bytes32 internal constant Z_24 =
        hex"cdc72595f74c7b1043d0e1ffbab734648c838dfb0527d971b602bc216c9619ef";
    bytes32 internal constant Z_25 =
        hex"0abf5ac974a1ed57f4050aa510dd9c74f508277b39d7973bb2dfccc5eeb0618d";
    bytes32 internal constant Z_26 =
        hex"b8cd74046ff337f0a7bf2c8e03e10f642c1886798d71806ab1e888d9e5ee87d0";
    bytes32 internal constant Z_27 =
        hex"838c5655cb21c6cb83313b5a631175dff4963772cce9108188b34ac87c81c41e";
    bytes32 internal constant Z_28 =
        hex"662ee4dd2dd7b2bc707961b1e646c4047669dcb6584f0d8d770daf5d7e7deb2e";
    bytes32 internal constant Z_29 =
        hex"388ab20e2573d171a88108e79d820e98f26c0b84aa8b2f4aa4968dbb818ea322";
    bytes32 internal constant Z_30 =
        hex"93237c50ba75ee485f4c22adf2f741400bdf8d6a9cc7df7ecae576221665d735";
    bytes32 internal constant Z_31 =
        hex"8448818bb4ae4562849e949e17ac16e0be16688e156b5cf15e098c627c0056a9";
}


// File contracts/isms/MultisigIsm.sol


pragma solidity >=0.8.0;

// ============ External Imports ============



// ============ Internal Imports ============




/**
 * @title MultisigIsm
 * @notice Manages an ownable set of validators that ECDSA sign checkpoints to
 * reach a quorum.
 */
contract MultisigIsm is IMultisigIsm, Ownable {
    // ============ Libraries ============

    using EnumerableSet for EnumerableSet.AddressSet;
    using Message for bytes;
    using MultisigIsmMetadata for bytes;
    using MerkleLib for MerkleLib.Tree;

    // ============ Constants ============

    uint8 public constant moduleType = 3;

    // ============ Mutable Storage ============

    /// @notice The validator threshold for each remote domain.
    mapping(uint32 => uint8) public threshold;

    /// @notice The validator set for each remote domain.
    mapping(uint32 => EnumerableSet.AddressSet) private validatorSet;

    /// @notice A succinct commitment to the validator set and threshold for each remote
    /// domain.
    mapping(uint32 => bytes32) public commitment;

    // ============ Events ============

    /**
     * @notice Emitted when a validator is enrolled in a validator set.
     * @param domain The remote domain of the validator set.
     * @param validator The address of the validator.
     * @param validatorCount The number of enrolled validators in the validator set.
     */
    event ValidatorEnrolled(
        uint32 indexed domain,
        address indexed validator,
        uint256 validatorCount
    );

    /**
     * @notice Emitted when a validator is unenrolled from a validator set.
     * @param domain The remote domain of the validator set.
     * @param validator The address of the validator.
     * @param validatorCount The number of enrolled validators in the validator set.
     */
    event ValidatorUnenrolled(
        uint32 indexed domain,
        address indexed validator,
        uint256 validatorCount
    );

    /**
     * @notice Emitted when the quorum threshold is set.
     * @param domain The remote domain of the validator set.
     * @param threshold The new quorum threshold.
     */
    event ThresholdSet(uint32 indexed domain, uint8 threshold);

    /**
     * @notice Emitted when the validator set or threshold changes.
     * @param domain The remote domain of the validator set.
     * @param commitment A commitment to the validator set and threshold.
     */
    event CommitmentUpdated(uint32 domain, bytes32 commitment);

    // ============ Constructor ============

    // solhint-disable-next-line no-empty-blocks
    constructor() Ownable() {}

    // ============ External Functions ============

    /**
     * @notice Enrolls multiple validators into a validator set.
     * @dev Reverts if `_validator` is already in the validator set.
     * @param _domains The remote domains of the validator sets.
     * @param _validators The validators to add to the validator sets.
     * @dev _validators[i] are the validators to enroll for _domains[i].
     */
    function enrollValidators(
        uint32[] calldata _domains,
        address[][] calldata _validators
    ) external onlyOwner {
        require(_domains.length == _validators.length, "!length");
        for (uint256 i = 0; i < _domains.length; i += 1) {
            address[] calldata _domainValidators = _validators[i];
            for (uint256 j = 0; j < _domainValidators.length; j += 1) {
                _enrollValidator(_domains[i], _domainValidators[j]);
            }
            _updateCommitment(_domains[i]);
        }
    }

    /**
     * @notice Enrolls a validator into a validator set.
     * @dev Reverts if `_validator` is already in the validator set.
     * @param _domain The remote domain of the validator set.
     * @param _validator The validator to add to the validator set.
     */
    function enrollValidator(uint32 _domain, address _validator)
        external
        onlyOwner
    {
        _enrollValidator(_domain, _validator);
        _updateCommitment(_domain);
    }

    /**
     * @notice Unenrolls a validator from a validator set.
     * @dev Reverts if `_validator` is not in the validator set.
     * @param _domain The remote domain of the validator set.
     * @param _validator The validator to remove from the validator set.
     */
    function unenrollValidator(uint32 _domain, address _validator)
        external
        onlyOwner
    {
        require(validatorSet[_domain].remove(_validator), "!enrolled");
        uint256 _validatorCount = validatorCount(_domain);
        require(
            _validatorCount >= threshold[_domain],
            "violates quorum threshold"
        );
        _updateCommitment(_domain);
        emit ValidatorUnenrolled(_domain, _validator, _validatorCount);
    }

    /**
     * @notice Sets the quorum threshold for multiple domains.
     * @param _domains The remote domains of the validator sets.
     * @param _thresholds The new quorum thresholds.
     */
    function setThresholds(
        uint32[] calldata _domains,
        uint8[] calldata _thresholds
    ) external onlyOwner {
        require(_domains.length == _thresholds.length, "!length");
        for (uint256 i = 0; i < _domains.length; i += 1) {
            setThreshold(_domains[i], _thresholds[i]);
        }
    }

    /**
     * @notice Returns whether an address is enrolled in a validator set.
     * @param _domain The remote domain of the validator set.
     * @param _address The address to test for set membership.
     * @return True if the address is enrolled, false otherwise.
     */
    function isEnrolled(uint32 _domain, address _address)
        external
        view
        returns (bool)
    {
        EnumerableSet.AddressSet storage _validatorSet = validatorSet[_domain];
        return _validatorSet.contains(_address);
    }

    // ============ Public Functions ============

    /**
     * @notice Sets the quorum threshold.
     * @param _domain The remote domain of the validator set.
     * @param _threshold The new quorum threshold.
     */
    function setThreshold(uint32 _domain, uint8 _threshold) public onlyOwner {
        require(
            _threshold > 0 && _threshold <= validatorCount(_domain),
            "!range"
        );
        threshold[_domain] = _threshold;
        emit ThresholdSet(_domain, _threshold);

        _updateCommitment(_domain);
    }

    /**
     * @notice Verifies that a quorum of the origin domain's validators signed
     * a checkpoint, and verifies the merkle proof of `_message` against that
     * checkpoint.
     * @param _metadata ABI encoded module metadata (see MultisigIsmMetadata.sol)
     * @param _message Formatted Hyperlane message (see Message.sol).
     */
    function verify(bytes calldata _metadata, bytes calldata _message)
        public
        view
        returns (bool)
    {
        require(_verifyMerkleProof(_metadata, _message), "!merkle");
        require(_verifyValidatorSignatures(_metadata, _message), "!sigs");
        return true;
    }

    /**
     * @notice Gets the current validator set
     * @param _domain The remote domain of the validator set.
     * @return The addresses of the validator set.
     */
    function validators(uint32 _domain) public view returns (address[] memory) {
        EnumerableSet.AddressSet storage _validatorSet = validatorSet[_domain];
        uint256 _validatorCount = _validatorSet.length();
        address[] memory _validators = new address[](_validatorCount);
        for (uint256 i = 0; i < _validatorCount; i++) {
            _validators[i] = _validatorSet.at(i);
        }
        return _validators;
    }

    /**
     * @notice Returns the set of validators responsible for verifying _message
     * and the number of signatures required
     * @dev Can change based on the content of _message
     * @param _message Hyperlane formatted interchain message
     * @return validators The array of validator addresses
     * @return threshold The number of validator signatures needed
     */
    function validatorsAndThreshold(bytes calldata _message)
        external
        view
        returns (address[] memory, uint8)
    {
        uint32 _origin = _message.origin();
        address[] memory _validators = validators(_origin);
        uint8 _threshold = threshold[_origin];
        return (_validators, _threshold);
    }

    /**
     * @notice Returns the number of validators enrolled in the validator set.
     * @param _domain The remote domain of the validator set.
     * @return The number of validators enrolled in the validator set.
     */
    function validatorCount(uint32 _domain) public view returns (uint256) {
        return validatorSet[_domain].length();
    }

    // ============ Internal Functions ============

    /**
     * @notice Enrolls a validator into a validator set.
     * @dev Reverts if `_validator` is already in the validator set.
     * @param _domain The remote domain of the validator set.
     * @param _validator The validator to add to the validator set.
     */
    function _enrollValidator(uint32 _domain, address _validator) internal {
        require(_validator != address(0), "zero address");
        require(validatorSet[_domain].add(_validator), "already enrolled");
        emit ValidatorEnrolled(_domain, _validator, validatorCount(_domain));
    }

    /**
     * @notice Updates the commitment to the validator set for `_domain`.
     * @param _domain The remote domain of the validator set.
     * @return The commitment to the validator set for `_domain`.
     */
    function _updateCommitment(uint32 _domain) internal returns (bytes32) {
        address[] memory _validators = validators(_domain);
        uint8 _threshold = threshold[_domain];
        bytes32 _commitment = keccak256(
            abi.encodePacked(_threshold, _validators)
        );
        commitment[_domain] = _commitment;
        emit CommitmentUpdated(_domain, _commitment);
        return _commitment;
    }

    /**
     * @notice Verifies the merkle proof of `_message` against the provided
     * checkpoint.
     * @param _metadata ABI encoded module metadata (see MultisigIsmMetadata.sol)
     * @param _message Formatted Hyperlane message (see Message.sol).
     */
    function _verifyMerkleProof(
        bytes calldata _metadata,
        bytes calldata _message
    ) internal pure returns (bool) {
        // calculate the expected root based on the proof
        bytes32 _calculatedRoot = MerkleLib.branchRoot(
            _message.id(),
            _metadata.proof(),
            _message.nonce()
        );
        return _calculatedRoot == _metadata.root();
    }

    /**
     * @notice Verifies that a quorum of the origin domain's validators signed
     * the provided checkpoint.
     * @param _metadata ABI encoded module metadata (see MultisigIsmMetadata.sol)
     * @param _message Formatted Hyperlane message (see Message.sol).
     */
    function _verifyValidatorSignatures(
        bytes calldata _metadata,
        bytes calldata _message
    ) internal view returns (bool) {
        uint8 _threshold = _metadata.threshold();
        bytes32 _digest;
        {
            uint32 _origin = _message.origin();

            bytes32 _commitment = keccak256(
                abi.encodePacked(_threshold, _metadata.validators())
            );
            // Ensures the validator set encoded in the metadata matches
            // what we've stored on chain.
            // NB: An empty validator set in `_metadata` will result in a
            // non-zero computed commitment, and this check will fail
            // as the commitment in storage will be zero.
            require(_commitment == commitment[_origin], "!commitment");
            _digest = _getCheckpointDigest(_metadata, _origin);
        }
        uint256 _validatorCount = _metadata.validatorCount();
        uint256 _validatorIndex = 0;
        // Assumes that signatures are ordered by validator
        for (uint256 i = 0; i < _threshold; ++i) {
            address _signer = ECDSA.recover(_digest, _metadata.signatureAt(i));
            // Loop through remaining validators until we find a match
            for (
                ;
                _validatorIndex < _validatorCount &&
                    _signer != _metadata.validatorAt(_validatorIndex);
                ++_validatorIndex
            ) {}
            // Fail if we never found a match
            require(_validatorIndex < _validatorCount, "!threshold");
            ++_validatorIndex;
        }
        return true;
    }

    /**
     * @notice Returns the domain hash that validators are expected to use
     * when signing checkpoints.
     * @param _origin The origin domain of the checkpoint.
     * @param _originMailbox The address of the origin mailbox as bytes32.
     * @return The domain hash.
     */
    function _getDomainHash(uint32 _origin, bytes32 _originMailbox)
        internal
        pure
        returns (bytes32)
    {
        // Including the origin mailbox address in the signature allows the slashing
        // protocol to enroll multiple mailboxes. Otherwise, a valid signature for
        // mailbox A would be indistinguishable from a fraudulent signature for mailbox
        // B.
        // The slashing protocol should slash if validators sign attestations for
        // anything other than a whitelisted mailbox.
        return
            keccak256(abi.encodePacked(_origin, _originMailbox, "HYPERLANE"));
    }

    /**
     * @notice Returns the digest validators are expected to sign when signing checkpoints.
     * @param _metadata ABI encoded module metadata (see MultisigIsmMetadata.sol)
     * @param _origin The origin domain of the checkpoint.
     * @return The digest of the checkpoint.
     */
    function _getCheckpointDigest(bytes calldata _metadata, uint32 _origin)
        internal
        pure
        returns (bytes32)
    {
        bytes32 _domainHash = _getDomainHash(
            _origin,
            _metadata.originMailbox()
        );
        return
            ECDSA.toEthSignedMessageHash(
                keccak256(
                    abi.encodePacked(
                        _domainHash,
                        _metadata.root(),
                        _metadata.index()
                    )
                )
            );
    }
}


// File @openzeppelin/contracts/utils/structs/EnumerableMap.sol@v4.8.0


// OpenZeppelin Contracts (last updated v4.8.0) (utils/structs/EnumerableMap.sol)
// This file was procedurally generated from scripts/generate/templates/EnumerableMap.js.

pragma solidity ^0.8.0;

/**
 * @dev Library for managing an enumerable variant of Solidity's
 * https://solidity.readthedocs.io/en/latest/types.html#mapping-types[`mapping`]
 * type.
 *
 * Maps have the following properties:
 *
 * - Entries are added, removed, and checked for existence in constant time
 * (O(1)).
 * - Entries are enumerated in O(n). No guarantees are made on the ordering.
 *
 * ```
 * contract Example {
 *     // Add the library methods
 *     using EnumerableMap for EnumerableMap.UintToAddressMap;
 *
 *     // Declare a set state variable
 *     EnumerableMap.UintToAddressMap private myMap;
 * }
 * ```
 *
 * The following map types are supported:
 *
 * - `uint256 -> address` (`UintToAddressMap`) since v3.0.0
 * - `address -> uint256` (`AddressToUintMap`) since v4.6.0
 * - `bytes32 -> bytes32` (`Bytes32ToBytes32Map`) since v4.6.0
 * - `uint256 -> uint256` (`UintToUintMap`) since v4.7.0
 * - `bytes32 -> uint256` (`Bytes32ToUintMap`) since v4.7.0
 *
 * [WARNING]
 * ====
 * Trying to delete such a structure from storage will likely result in data corruption, rendering the structure
 * unusable.
 * See https://github.com/ethereum/solidity/pull/11843[ethereum/solidity#11843] for more info.
 *
 * In order to clean an EnumerableMap, you can either remove all elements one by one or create a fresh instance using an
 * array of EnumerableMap.
 * ====
 */
library EnumerableMap {
    using EnumerableSet for EnumerableSet.Bytes32Set;

    // To implement this library for multiple types with as little code
    // repetition as possible, we write it in terms of a generic Map type with
    // bytes32 keys and values.
    // The Map implementation uses private functions, and user-facing
    // implementations (such as Uint256ToAddressMap) are just wrappers around
    // the underlying Map.
    // This means that we can only create new EnumerableMaps for types that fit
    // in bytes32.

    struct Bytes32ToBytes32Map {
        // Storage of keys
        EnumerableSet.Bytes32Set _keys;
        mapping(bytes32 => bytes32) _values;
    }

    /**
     * @dev Adds a key-value pair to a map, or updates the value for an existing
     * key. O(1).
     *
     * Returns true if the key was added to the map, that is if it was not
     * already present.
     */
    function set(
        Bytes32ToBytes32Map storage map,
        bytes32 key,
        bytes32 value
    ) internal returns (bool) {
        map._values[key] = value;
        return map._keys.add(key);
    }

    /**
     * @dev Removes a key-value pair from a map. O(1).
     *
     * Returns true if the key was removed from the map, that is if it was present.
     */
    function remove(Bytes32ToBytes32Map storage map, bytes32 key) internal returns (bool) {
        delete map._values[key];
        return map._keys.remove(key);
    }

    /**
     * @dev Returns true if the key is in the map. O(1).
     */
    function contains(Bytes32ToBytes32Map storage map, bytes32 key) internal view returns (bool) {
        return map._keys.contains(key);
    }

    /**
     * @dev Returns the number of key-value pairs in the map. O(1).
     */
    function length(Bytes32ToBytes32Map storage map) internal view returns (uint256) {
        return map._keys.length();
    }

    /**
     * @dev Returns the key-value pair stored at position `index` in the map. O(1).
     *
     * Note that there are no guarantees on the ordering of entries inside the
     * array, and it may change when more entries are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(Bytes32ToBytes32Map storage map, uint256 index) internal view returns (bytes32, bytes32) {
        bytes32 key = map._keys.at(index);
        return (key, map._values[key]);
    }

    /**
     * @dev Tries to returns the value associated with `key`. O(1).
     * Does not revert if `key` is not in the map.
     */
    function tryGet(Bytes32ToBytes32Map storage map, bytes32 key) internal view returns (bool, bytes32) {
        bytes32 value = map._values[key];
        if (value == bytes32(0)) {
            return (contains(map, key), bytes32(0));
        } else {
            return (true, value);
        }
    }

    /**
     * @dev Returns the value associated with `key`. O(1).
     *
     * Requirements:
     *
     * - `key` must be in the map.
     */
    function get(Bytes32ToBytes32Map storage map, bytes32 key) internal view returns (bytes32) {
        bytes32 value = map._values[key];
        require(value != 0 || contains(map, key), "EnumerableMap: nonexistent key");
        return value;
    }

    /**
     * @dev Same as {get}, with a custom error message when `key` is not in the map.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryGet}.
     */
    function get(
        Bytes32ToBytes32Map storage map,
        bytes32 key,
        string memory errorMessage
    ) internal view returns (bytes32) {
        bytes32 value = map._values[key];
        require(value != 0 || contains(map, key), errorMessage);
        return value;
    }

    // UintToUintMap

    struct UintToUintMap {
        Bytes32ToBytes32Map _inner;
    }

    /**
     * @dev Adds a key-value pair to a map, or updates the value for an existing
     * key. O(1).
     *
     * Returns true if the key was added to the map, that is if it was not
     * already present.
     */
    function set(
        UintToUintMap storage map,
        uint256 key,
        uint256 value
    ) internal returns (bool) {
        return set(map._inner, bytes32(key), bytes32(value));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the key was removed from the map, that is if it was present.
     */
    function remove(UintToUintMap storage map, uint256 key) internal returns (bool) {
        return remove(map._inner, bytes32(key));
    }

    /**
     * @dev Returns true if the key is in the map. O(1).
     */
    function contains(UintToUintMap storage map, uint256 key) internal view returns (bool) {
        return contains(map._inner, bytes32(key));
    }

    /**
     * @dev Returns the number of elements in the map. O(1).
     */
    function length(UintToUintMap storage map) internal view returns (uint256) {
        return length(map._inner);
    }

    /**
     * @dev Returns the element stored at position `index` in the set. O(1).
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(UintToUintMap storage map, uint256 index) internal view returns (uint256, uint256) {
        (bytes32 key, bytes32 value) = at(map._inner, index);
        return (uint256(key), uint256(value));
    }

    /**
     * @dev Tries to returns the value associated with `key`. O(1).
     * Does not revert if `key` is not in the map.
     */
    function tryGet(UintToUintMap storage map, uint256 key) internal view returns (bool, uint256) {
        (bool success, bytes32 value) = tryGet(map._inner, bytes32(key));
        return (success, uint256(value));
    }

    /**
     * @dev Returns the value associated with `key`. O(1).
     *
     * Requirements:
     *
     * - `key` must be in the map.
     */
    function get(UintToUintMap storage map, uint256 key) internal view returns (uint256) {
        return uint256(get(map._inner, bytes32(key)));
    }

    /**
     * @dev Same as {get}, with a custom error message when `key` is not in the map.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryGet}.
     */
    function get(
        UintToUintMap storage map,
        uint256 key,
        string memory errorMessage
    ) internal view returns (uint256) {
        return uint256(get(map._inner, bytes32(key), errorMessage));
    }

    // UintToAddressMap

    struct UintToAddressMap {
        Bytes32ToBytes32Map _inner;
    }

    /**
     * @dev Adds a key-value pair to a map, or updates the value for an existing
     * key. O(1).
     *
     * Returns true if the key was added to the map, that is if it was not
     * already present.
     */
    function set(
        UintToAddressMap storage map,
        uint256 key,
        address value
    ) internal returns (bool) {
        return set(map._inner, bytes32(key), bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the key was removed from the map, that is if it was present.
     */
    function remove(UintToAddressMap storage map, uint256 key) internal returns (bool) {
        return remove(map._inner, bytes32(key));
    }

    /**
     * @dev Returns true if the key is in the map. O(1).
     */
    function contains(UintToAddressMap storage map, uint256 key) internal view returns (bool) {
        return contains(map._inner, bytes32(key));
    }

    /**
     * @dev Returns the number of elements in the map. O(1).
     */
    function length(UintToAddressMap storage map) internal view returns (uint256) {
        return length(map._inner);
    }

    /**
     * @dev Returns the element stored at position `index` in the set. O(1).
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(UintToAddressMap storage map, uint256 index) internal view returns (uint256, address) {
        (bytes32 key, bytes32 value) = at(map._inner, index);
        return (uint256(key), address(uint160(uint256(value))));
    }

    /**
     * @dev Tries to returns the value associated with `key`. O(1).
     * Does not revert if `key` is not in the map.
     */
    function tryGet(UintToAddressMap storage map, uint256 key) internal view returns (bool, address) {
        (bool success, bytes32 value) = tryGet(map._inner, bytes32(key));
        return (success, address(uint160(uint256(value))));
    }

    /**
     * @dev Returns the value associated with `key`. O(1).
     *
     * Requirements:
     *
     * - `key` must be in the map.
     */
    function get(UintToAddressMap storage map, uint256 key) internal view returns (address) {
        return address(uint160(uint256(get(map._inner, bytes32(key)))));
    }

    /**
     * @dev Same as {get}, with a custom error message when `key` is not in the map.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryGet}.
     */
    function get(
        UintToAddressMap storage map,
        uint256 key,
        string memory errorMessage
    ) internal view returns (address) {
        return address(uint160(uint256(get(map._inner, bytes32(key), errorMessage))));
    }

    // AddressToUintMap

    struct AddressToUintMap {
        Bytes32ToBytes32Map _inner;
    }

    /**
     * @dev Adds a key-value pair to a map, or updates the value for an existing
     * key. O(1).
     *
     * Returns true if the key was added to the map, that is if it was not
     * already present.
     */
    function set(
        AddressToUintMap storage map,
        address key,
        uint256 value
    ) internal returns (bool) {
        return set(map._inner, bytes32(uint256(uint160(key))), bytes32(value));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the key was removed from the map, that is if it was present.
     */
    function remove(AddressToUintMap storage map, address key) internal returns (bool) {
        return remove(map._inner, bytes32(uint256(uint160(key))));
    }

    /**
     * @dev Returns true if the key is in the map. O(1).
     */
    function contains(AddressToUintMap storage map, address key) internal view returns (bool) {
        return contains(map._inner, bytes32(uint256(uint160(key))));
    }

    /**
     * @dev Returns the number of elements in the map. O(1).
     */
    function length(AddressToUintMap storage map) internal view returns (uint256) {
        return length(map._inner);
    }

    /**
     * @dev Returns the element stored at position `index` in the set. O(1).
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(AddressToUintMap storage map, uint256 index) internal view returns (address, uint256) {
        (bytes32 key, bytes32 value) = at(map._inner, index);
        return (address(uint160(uint256(key))), uint256(value));
    }

    /**
     * @dev Tries to returns the value associated with `key`. O(1).
     * Does not revert if `key` is not in the map.
     */
    function tryGet(AddressToUintMap storage map, address key) internal view returns (bool, uint256) {
        (bool success, bytes32 value) = tryGet(map._inner, bytes32(uint256(uint160(key))));
        return (success, uint256(value));
    }

    /**
     * @dev Returns the value associated with `key`. O(1).
     *
     * Requirements:
     *
     * - `key` must be in the map.
     */
    function get(AddressToUintMap storage map, address key) internal view returns (uint256) {
        return uint256(get(map._inner, bytes32(uint256(uint160(key)))));
    }

    /**
     * @dev Same as {get}, with a custom error message when `key` is not in the map.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryGet}.
     */
    function get(
        AddressToUintMap storage map,
        address key,
        string memory errorMessage
    ) internal view returns (uint256) {
        return uint256(get(map._inner, bytes32(uint256(uint160(key))), errorMessage));
    }

    // Bytes32ToUintMap

    struct Bytes32ToUintMap {
        Bytes32ToBytes32Map _inner;
    }

    /**
     * @dev Adds a key-value pair to a map, or updates the value for an existing
     * key. O(1).
     *
     * Returns true if the key was added to the map, that is if it was not
     * already present.
     */
    function set(
        Bytes32ToUintMap storage map,
        bytes32 key,
        uint256 value
    ) internal returns (bool) {
        return set(map._inner, key, bytes32(value));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the key was removed from the map, that is if it was present.
     */
    function remove(Bytes32ToUintMap storage map, bytes32 key) internal returns (bool) {
        return remove(map._inner, key);
    }

    /**
     * @dev Returns true if the key is in the map. O(1).
     */
    function contains(Bytes32ToUintMap storage map, bytes32 key) internal view returns (bool) {
        return contains(map._inner, key);
    }

    /**
     * @dev Returns the number of elements in the map. O(1).
     */
    function length(Bytes32ToUintMap storage map) internal view returns (uint256) {
        return length(map._inner);
    }

    /**
     * @dev Returns the element stored at position `index` in the set. O(1).
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(Bytes32ToUintMap storage map, uint256 index) internal view returns (bytes32, uint256) {
        (bytes32 key, bytes32 value) = at(map._inner, index);
        return (key, uint256(value));
    }

    /**
     * @dev Tries to returns the value associated with `key`. O(1).
     * Does not revert if `key` is not in the map.
     */
    function tryGet(Bytes32ToUintMap storage map, bytes32 key) internal view returns (bool, uint256) {
        (bool success, bytes32 value) = tryGet(map._inner, key);
        return (success, uint256(value));
    }

    /**
     * @dev Returns the value associated with `key`. O(1).
     *
     * Requirements:
     *
     * - `key` must be in the map.
     */
    function get(Bytes32ToUintMap storage map, bytes32 key) internal view returns (uint256) {
        return uint256(get(map._inner, key));
    }

    /**
     * @dev Same as {get}, with a custom error message when `key` is not in the map.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryGet}.
     */
    function get(
        Bytes32ToUintMap storage map,
        bytes32 key,
        string memory errorMessage
    ) internal view returns (uint256) {
        return uint256(get(map._inner, key, errorMessage));
    }
}


// File contracts/libs/EnumerableMapExtended.sol


pragma solidity >=0.6.11;

// ============ External Imports ============

// extends EnumerableMap with uint256 => bytes32 type
// modelled after https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v4.8.0/contracts/utils/structs/EnumerableMap.sol
library EnumerableMapExtended {
    using EnumerableMap for EnumerableMap.Bytes32ToBytes32Map;

    struct UintToBytes32Map {
        EnumerableMap.Bytes32ToBytes32Map _inner;
    }

    // ============ Library Functions ============
    function keys(UintToBytes32Map storage map)
        internal
        view
        returns (bytes32[] storage)
    {
        return map._inner._keys._inner._values;
    }

    function set(
        UintToBytes32Map storage map,
        uint256 key,
        bytes32 value
    ) internal {
        map._inner.set(bytes32(key), value);
    }

    function get(UintToBytes32Map storage map, uint256 key)
        internal
        view
        returns (bytes32)
    {
        return map._inner.get(bytes32(key));
    }

    function remove(UintToBytes32Map storage map, uint256 key)
        internal
        returns (bool)
    {
        return map._inner.remove(bytes32(key));
    }

    function contains(UintToBytes32Map storage map, uint256 key)
        internal
        view
        returns (bool)
    {
        return map._inner.contains(bytes32(key));
    }

    function length(UintToBytes32Map storage map)
        internal
        view
        returns (uint256)
    {
        return map._inner.length();
    }

    function at(UintToBytes32Map storage map, uint256 index)
        internal
        view
        returns (uint256, bytes32)
    {
        (bytes32 key, bytes32 value) = map._inner.at(index);
        return (uint256(key), value);
    }
}


// File contracts/upgrade/Versioned.sol


pragma solidity >=0.6.11;

/**
 * @title Versioned
 * @notice Version getter for contracts
 **/
contract Versioned {
    uint8 public constant VERSION = 0;
}


// File interfaces/IMessageRecipient.sol


pragma solidity >=0.6.11;

interface IMessageRecipient {
    function handle(
        uint32 _origin,
        bytes32 _sender,
        bytes calldata _message
    ) external;
}


// File contracts/PausableReentrancyGuard.sol


pragma solidity >=0.8.0;

// adapted from "@openzeppelin/contracts-upgradeable/security/ReentrancyGuardUpgradeable.sol";
abstract contract PausableReentrancyGuardUpgradeable is Initializable {
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;
    uint256 private constant _PAUSED = 3;

    uint256 private _status;

    /**
     * @dev MUST be called for `nonReentrant` to not always revert
     */
    function __PausableReentrancyGuard_init() internal onlyInitializing {
        _status = _NOT_ENTERED;
    }

    function _isPaused() internal view returns (bool) {
        return _status == _PAUSED;
    }

    function _pause() internal notPaused {
        _status = _PAUSED;
    }

    function _unpause() internal {
        require(_isPaused(), "!paused");
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from being entered when paused.
     */
    modifier notPaused() {
        require(!_isPaused(), "paused");
        _;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and making it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrantAndNotPaused() {
        // status must have been initialized
        require(_status == _NOT_ENTERED, "reentrant call (or paused)");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[49] private __gap;
}


// File contracts/Mailbox.sol


pragma solidity >=0.8.0;

// ============ Internal Imports ============








// ============ External Imports ============


contract Mailbox is
    IMailbox,
    OwnableUpgradeable,
    PausableReentrancyGuardUpgradeable,
    Versioned
{
    // ============ Libraries ============

    using MerkleLib for MerkleLib.Tree;
    using Message for bytes;
    using TypeCasts for bytes32;
    using TypeCasts for address;

    // ============ Constants ============

    // Maximum bytes per message = 2 KiB (somewhat arbitrarily set to begin)
    uint256 public constant MAX_MESSAGE_BODY_BYTES = 2 * 2**10;
    // Domain of chain on which the contract is deployed
    uint32 public immutable localDomain;

    // ============ Public Storage ============

    // The default ISM, used if the recipient fails to specify one.
    IInterchainSecurityModule public defaultIsm;
    // An incremental merkle tree used to store outbound message IDs.
    MerkleLib.Tree public tree;
    // Mapping of message ID to whether or not that message has been delivered.
    mapping(bytes32 => bool) public delivered;

    // ============ Upgrade Gap ============

    // gap for upgrade safety
    uint256[47] private __GAP;

    // ============ Events ============

    /**
     * @notice Emitted when the default ISM is updated
     * @param module The new default ISM
     */
    event DefaultIsmSet(address indexed module);

    /**
     * @notice Emitted when a new message is dispatched via Hyperlane
     * @param sender The address that dispatched the message
     * @param destination The destination domain of the message
     * @param recipient The message recipient address on `destination`
     * @param message Raw bytes of message
     */
    event Dispatch(
        address indexed sender,
        uint32 indexed destination,
        bytes32 indexed recipient,
        bytes message
    );

    /**
     * @notice Emitted when a new message is dispatched via Hyperlane
     * @param messageId The unique message identifier
     */
    event DispatchId(bytes32 indexed messageId);

    /**
     * @notice Emitted when a Hyperlane message is processed
     * @param messageId The unique message identifier
     */
    event ProcessId(bytes32 indexed messageId);

    /**
     * @notice Emitted when a Hyperlane message is delivered
     * @param origin The origin domain of the message
     * @param sender The message sender address on `origin`
     * @param recipient The address that handled the message
     */
    event Process(
        uint32 indexed origin,
        bytes32 indexed sender,
        address indexed recipient
    );

    /**
     * @notice Emitted when Mailbox is paused
     */
    event Paused();

    /**
     * @notice Emitted when Mailbox is unpaused
     */
    event Unpaused();

    // ============ Constructor ============

    // solhint-disable-next-line no-empty-blocks
    constructor(uint32 _localDomain) {
        localDomain = _localDomain;
    }

    // ============ Initializers ============

    function initialize(address _owner, address _defaultIsm)
        external
        initializer
    {
        __PausableReentrancyGuard_init();
        __Ownable_init();
        transferOwnership(_owner);
        _setDefaultIsm(_defaultIsm);
    }

    // ============ External Functions ============

    /**
     * @notice Sets the default ISM for the Mailbox.
     * @param _module The new default ISM. Must be a contract.
     */
    function setDefaultIsm(address _module) external onlyOwner {
        _setDefaultIsm(_module);
    }

    /**
     * @notice Dispatches a message to the destination domain & recipient.
     * @param _destinationDomain Domain of destination chain
     * @param _recipientAddress Address of recipient on destination chain as bytes32
     * @param _messageBody Raw bytes content of message body
     * @return The message ID inserted into the Mailbox's merkle tree
     */
    function dispatch(
        uint32 _destinationDomain,
        bytes32 _recipientAddress,
        bytes calldata _messageBody
    ) external override notPaused returns (bytes32) {
        require(_messageBody.length <= MAX_MESSAGE_BODY_BYTES, "msg too long");
        // Format the message into packed bytes.
        bytes memory _message = Message.formatMessage(
            VERSION,
            count(),
            localDomain,
            msg.sender.addressToBytes32(),
            _destinationDomain,
            _recipientAddress,
            _messageBody
        );

        // Insert the message ID into the merkle tree.
        bytes32 _id = _message.id();
        tree.insert(_id);
        emit Dispatch(
            msg.sender,
            _destinationDomain,
            _recipientAddress,
            _message
        );
        emit DispatchId(_id);
        return _id;
    }

    /**
     * @notice Attempts to deliver `_message` to its recipient. Verifies
     * `_message` via the recipient's ISM using the provided `_metadata`.
     * @param _metadata Metadata used by the ISM to verify `_message`.
     * @param _message Formatted Hyperlane message (refer to Message.sol).
     */
    function process(bytes calldata _metadata, bytes calldata _message)
        external
        override
        nonReentrantAndNotPaused
    {
        // Check that the message was intended for this mailbox.
        require(_message.version() == VERSION, "!version");
        require(_message.destination() == localDomain, "!destination");

        // Check that the message hasn't already been delivered.
        bytes32 _id = _message.id();
        require(delivered[_id] == false, "delivered");
        delivered[_id] = true;

        // Verify the message via the ISM.
        IInterchainSecurityModule _ism = IInterchainSecurityModule(
            recipientIsm(_message.recipientAddress())
        );
        require(_ism.verify(_metadata, _message), "!module");

        // Deliver the message to the recipient.
        uint32 origin = _message.origin();
        bytes32 sender = _message.sender();
        address recipient = _message.recipientAddress();
        IMessageRecipient(recipient).handle(origin, sender, _message.body());
        emit Process(origin, sender, recipient);
        emit ProcessId(_id);
    }

    // ============ Public Functions ============

    /**
     * @notice Calculates and returns tree's current root
     */
    function root() public view returns (bytes32) {
        return tree.root();
    }

    /**
     * @notice Returns the number of inserted leaves in the tree
     */
    function count() public view returns (uint32) {
        // count cannot exceed 2**TREE_DEPTH, see MerkleLib.sol
        return uint32(tree.count);
    }

    /**
     * @notice Returns a checkpoint representing the current merkle tree.
     * @return root The root of the Mailbox's merkle tree.
     * @return index The index of the last element in the tree.
     */
    function latestCheckpoint() public view returns (bytes32, uint32) {
        return (root(), count() - 1);
    }

    /**
     * @notice Pauses mailbox and prevents further dispatch/process calls
     * @dev Only `owner` can pause the mailbox.
     */
    function pause() external onlyOwner {
        _pause();
        emit Paused();
    }

    /**
     * @notice Unpauses mailbox and allows for message processing.
     * @dev Only `owner` can unpause the mailbox.
     */
    function unpause() external onlyOwner {
        _unpause();
        emit Unpaused();
    }

    /**
     * @notice Returns whether mailbox is paused.
     */
    function isPaused() external view returns (bool) {
        return _isPaused();
    }

    /**
     * @notice Returns the ISM to use for the recipient, defaulting to the
     * default ISM if none is specified.
     * @param _recipient The message recipient whose ISM should be returned.
     * @return The ISM to use for `_recipient`.
     */
    function recipientIsm(address _recipient)
        public
        view
        returns (IInterchainSecurityModule)
    {
        // Use a default interchainSecurityModule if one is not specified by the
        // recipient.
        // This is useful for backwards compatibility and for convenience as
        // recipients are not mandated to specify an ISM.
        try
            ISpecifiesInterchainSecurityModule(_recipient)
                .interchainSecurityModule()
        returns (IInterchainSecurityModule _val) {
            // If the recipient specifies a zero address, use the default ISM.
            if (address(_val) != address(0)) {
                return _val;
            }
        } catch {}
        return defaultIsm;
    }

    // ============ Internal Functions ============

    /**
     * @notice Sets the default ISM for the Mailbox.
     * @param _module The new default ISM. Must be a contract.
     */
    function _setDefaultIsm(address _module) internal {
        require(Address.isContract(_module), "!contract");
        defaultIsm = IInterchainSecurityModule(_module);
        emit DefaultIsmSet(_module);
    }
}


// File contracts/Call.sol


pragma solidity ^0.8.13;

struct Call {
    address to;
    bytes data;
}


// File contracts/OwnableMulticall.sol


pragma solidity ^0.8.13;

// ============ External Imports ============


/*
 * @title OwnableMulticall
 * @dev Allows only only address to execute calls to other contracts
 */
contract OwnableMulticall is OwnableUpgradeable {
    constructor() {
        _transferOwnership(msg.sender);
    }

    function initialize() external initializer {
        _transferOwnership(msg.sender);
    }

    function proxyCalls(Call[] calldata calls) external onlyOwner {
        for (uint256 i = 0; i < calls.length; i += 1) {
            (bool success, bytes memory returnData) = calls[i].to.call(
                calls[i].data
            );
            if (!success) {
                assembly {
                    revert(add(returnData, 32), returnData)
                }
            }
        }
    }

    function _call(Call[] memory calls, bytes[] memory callbacks)
        internal
        returns (bytes[] memory resolveCalls)
    {
        resolveCalls = new bytes[](callbacks.length);
        for (uint256 i = 0; i < calls.length; i++) {
            (bool success, bytes memory returnData) = calls[i].to.call(
                calls[i].data
            );
            require(success, "Multicall: call failed");
            resolveCalls[i] = bytes.concat(callbacks[i], returnData);
        }
    }

    // TODO: deduplicate
    function proxyCallBatch(address to, bytes[] memory calls) internal {
        for (uint256 i = 0; i < calls.length; i += 1) {
            (bool success, bytes memory returnData) = to.call(calls[i]);
            if (!success) {
                assembly {
                    revert(add(returnData, 32), returnData)
                }
            }
        }
    }
}


// File contracts/Router.sol


pragma solidity >=0.6.11;

// ============ Internal Imports ============





abstract contract Router is HyperlaneConnectionClient, IMessageRecipient {
    using EnumerableMapExtended for EnumerableMapExtended.UintToBytes32Map;

    string constant NO_ROUTER_ENROLLED_REVERT_MESSAGE =
        "No router enrolled for domain. Did you specify the right domain ID?";

    // ============ Mutable Storage ============
    EnumerableMapExtended.UintToBytes32Map internal _routers;
    uint256[49] private __GAP; // gap for upgrade safety

    // ============ Events ============

    /**
     * @notice Emitted when a router is set.
     * @param domain The domain of the new router
     * @param router The address of the new router
     */
    event RemoteRouterEnrolled(uint32 indexed domain, bytes32 indexed router);

    // ============ Modifiers ============
    /**
     * @notice Only accept messages from a remote Router contract
     * @param _origin The domain the message is coming from
     * @param _router The address the message is coming from
     */
    modifier onlyRemoteRouter(uint32 _origin, bytes32 _router) {
        require(
            _isRemoteRouter(_origin, _router),
            NO_ROUTER_ENROLLED_REVERT_MESSAGE
        );
        _;
    }

    // ======== Initializer =========
    function __Router_initialize(address _mailbox) internal onlyInitializing {
        __HyperlaneConnectionClient_initialize(_mailbox);
    }

    function __Router_initialize(
        address _mailbox,
        address _interchainGasPaymaster
    ) internal onlyInitializing {
        __HyperlaneConnectionClient_initialize(
            _mailbox,
            _interchainGasPaymaster
        );
    }

    function __Router_initialize(
        address _mailbox,
        address _interchainGasPaymaster,
        address _interchainSecurityModule
    ) internal onlyInitializing {
        __HyperlaneConnectionClient_initialize(
            _mailbox,
            _interchainGasPaymaster,
            _interchainSecurityModule
        );
    }

    // ============ External functions ============
    function domains() external view returns (uint32[] memory) {
        bytes32[] storage rawKeys = _routers.keys();
        uint32[] memory keys = new uint32[](rawKeys.length);
        for (uint256 i = 0; i < rawKeys.length; i++) {
            keys[i] = uint32(uint256(rawKeys[i]));
        }
        return keys;
    }

    function routers(uint32 _domain) public view returns (bytes32) {
        if (_routers.contains(_domain)) {
            return _routers.get(_domain);
        } else {
            return bytes32(0); // for backwards compatibility with storage mapping
        }
    }

    /**
     * @notice Register the address of a Router contract for the same Application on a remote chain
     * @param _domain The domain of the remote Application Router
     * @param _router The address of the remote Application Router
     */
    function enrollRemoteRouter(uint32 _domain, bytes32 _router)
        external
        virtual
        onlyOwner
    {
        _enrollRemoteRouter(_domain, _router);
    }

    /**
     * @notice Batch version of `enrollRemoteRouter`
     * @param _domains The domaisn of the remote Application Routers
     * @param _addresses The addresses of the remote Application Routers
     */
    function enrollRemoteRouters(
        uint32[] calldata _domains,
        bytes32[] calldata _addresses
    ) external virtual onlyOwner {
        require(_domains.length == _addresses.length, "!length");
        for (uint256 i = 0; i < _domains.length; i += 1) {
            _enrollRemoteRouter(_domains[i], _addresses[i]);
        }
    }

    /**
     * @notice Handles an incoming message
     * @param _origin The origin domain
     * @param _sender The sender address
     * @param _message The message
     */
    function handle(
        uint32 _origin,
        bytes32 _sender,
        bytes calldata _message
    ) external virtual override onlyMailbox onlyRemoteRouter(_origin, _sender) {
        // TODO: callbacks on success/failure
        _handle(_origin, _sender, _message);
    }

    // ============ Virtual functions ============
    function _handle(
        uint32 _origin,
        bytes32 _sender,
        bytes calldata _message
    ) internal virtual;

    // ============ Internal functions ============

    /**
     * @notice Set the router for a given domain
     * @param _domain The domain
     * @param _address The new router
     */
    function _enrollRemoteRouter(uint32 _domain, bytes32 _address) internal {
        _routers.set(_domain, _address);
        emit RemoteRouterEnrolled(_domain, _address);
    }

    /**
     * @notice Return true if the given domain / router is the address of a remote Application Router
     * @param _domain The domain of the potential remote Application Router
     * @param _address The address of the potential remote Application Router
     */
    function _isRemoteRouter(uint32 _domain, bytes32 _address)
        internal
        view
        returns (bool)
    {
        return routers(_domain) == _address;
    }

    /**
     * @notice Assert that the given domain has a Application Router registered and return its address
     * @param _domain The domain of the chain for which to get the Application Router
     * @return _router The address of the remote Application Router on _domain
     */
    function _mustHaveRemoteRouter(uint32 _domain)
        internal
        view
        returns (bytes32 _router)
    {
        _router = routers(_domain);
        require(_router != bytes32(0), NO_ROUTER_ENROLLED_REVERT_MESSAGE);
    }

    /**
     * @notice Dispatches a message to an enrolled router via the local router's Mailbox
     * and pays for it to be relayed to the destination.
     * @dev Reverts if there is no enrolled router for _destinationDomain.
     * @param _destinationDomain The domain of the chain to which to send the message.
     * @param _messageBody Raw bytes content of message.
     * @param _gasAmount The amount of destination gas for the message that is requested via the InterchainGasPaymaster.
     * @param _gasPayment The amount of native tokens to pay for the message to be relayed.
     * @param _gasPaymentRefundAddress The address to refund any gas overpayment to.
     */
    function _dispatchWithGas(
        uint32 _destinationDomain,
        bytes memory _messageBody,
        uint256 _gasAmount,
        uint256 _gasPayment,
        address _gasPaymentRefundAddress
    ) internal returns (bytes32 _messageId) {
        _messageId = _dispatch(_destinationDomain, _messageBody);
        // Call the IGP even if the gas payment is zero. This is to support on-chain
        // fee quoting in IGPs, which should always revert if gas payment is insufficient.
        interchainGasPaymaster.payForGas{value: _gasPayment}(
            _messageId,
            _destinationDomain,
            _gasAmount,
            _gasPaymentRefundAddress
        );
    }

    /**
     * @notice Dispatches a message to an enrolled router via the provided Mailbox.
     * @dev Does not pay interchain gas.
     * @dev Reverts if there is no enrolled router for _destinationDomain.
     * @param _destinationDomain The domain of the chain to which to send the message.
     * @param _messageBody Raw bytes content of message.
     */
    function _dispatch(uint32 _destinationDomain, bytes memory _messageBody)
        internal
        virtual
        returns (bytes32)
    {
        // Ensure that destination chain has an enrolled router.
        bytes32 _router = _mustHaveRemoteRouter(_destinationDomain);
        return mailbox.dispatch(_destinationDomain, _router, _messageBody);
    }
}


// File interfaces/IInterchainAccountRouter.sol


pragma solidity >=0.6.11;

interface IInterchainAccountRouter {
    function dispatch(uint32 _destinationDomain, Call[] calldata calls)
        external
        returns (bytes32);

    function dispatch(
        uint32 _destinationDomain,
        address target,
        bytes calldata data
    ) external returns (bytes32);

    function getInterchainAccount(uint32 _originDomain, address _sender)
        external
        view
        returns (address);
}


// File contracts/libs/MinimalProxy.sol


pragma solidity >=0.6.11;

// Library for building bytecode of minimal proxies (see https://eips.ethereum.org/EIPS/eip-1167)
library MinimalProxy {
    bytes20 constant PREFIX = hex"3d602d80600a3d3981f3363d3d373d3d3d363d73";
    bytes15 constant SUFFIX = hex"5af43d82803e903d91602b57fd5bf3";

    function bytecode(address implementation)
        internal
        pure
        returns (bytes memory)
    {
        return abi.encodePacked(PREFIX, bytes20(implementation), SUFFIX);
    }
}


// File @openzeppelin/contracts/utils/Create2.sol@v4.8.0


// OpenZeppelin Contracts (last updated v4.8.0) (utils/Create2.sol)

pragma solidity ^0.8.0;

/**
 * @dev Helper to make usage of the `CREATE2` EVM opcode easier and safer.
 * `CREATE2` can be used to compute in advance the address where a smart
 * contract will be deployed, which allows for interesting new mechanisms known
 * as 'counterfactual interactions'.
 *
 * See the https://eips.ethereum.org/EIPS/eip-1014#motivation[EIP] for more
 * information.
 */
library Create2 {
    /**
     * @dev Deploys a contract using `CREATE2`. The address where the contract
     * will be deployed can be known in advance via {computeAddress}.
     *
     * The bytecode for a contract can be obtained from Solidity with
     * `type(contractName).creationCode`.
     *
     * Requirements:
     *
     * - `bytecode` must not be empty.
     * - `salt` must have not been used for `bytecode` already.
     * - the factory must have a balance of at least `amount`.
     * - if `amount` is non-zero, `bytecode` must have a `payable` constructor.
     */
    function deploy(
        uint256 amount,
        bytes32 salt,
        bytes memory bytecode
    ) internal returns (address addr) {
        require(address(this).balance >= amount, "Create2: insufficient balance");
        require(bytecode.length != 0, "Create2: bytecode length is zero");
        /// @solidity memory-safe-assembly
        assembly {
            addr := create2(amount, add(bytecode, 0x20), mload(bytecode), salt)
        }
        require(addr != address(0), "Create2: Failed on deploy");
    }

    /**
     * @dev Returns the address where a contract will be stored if deployed via {deploy}. Any change in the
     * `bytecodeHash` or `salt` will result in a new destination address.
     */
    function computeAddress(bytes32 salt, bytes32 bytecodeHash) internal view returns (address) {
        return computeAddress(salt, bytecodeHash, address(this));
    }

    /**
     * @dev Returns the address where a contract will be stored if deployed via {deploy} from a contract located at
     * `deployer`. If `deployer` is this contract's address, returns the same value as {computeAddress}.
     */
    function computeAddress(
        bytes32 salt,
        bytes32 bytecodeHash,
        address deployer
    ) internal pure returns (address addr) {
        /// @solidity memory-safe-assembly
        assembly {
            let ptr := mload(0x40) // Get free memory pointer

            // |                   | ↓ ptr ...  ↓ ptr + 0x0B (start) ...  ↓ ptr + 0x20 ...  ↓ ptr + 0x40 ...   |
            // |-------------------|---------------------------------------------------------------------------|
            // | bytecodeHash      |                                                        CCCCCCCCCCCCC...CC |
            // | salt              |                                      BBBBBBBBBBBBB...BB                   |
            // | deployer          | 000000...0000AAAAAAAAAAAAAAAAAAA...AA                                     |
            // | 0xFF              |            FF                                                             |
            // |-------------------|---------------------------------------------------------------------------|
            // | memory            | 000000...00FFAAAAAAAAAAAAAAAAAAA...AABBBBBBBBBBBBB...BBCCCCCCCCCCCCC...CC |
            // | keccak(start, 85) |            ↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑ |

            mstore(add(ptr, 0x40), bytecodeHash)
            mstore(add(ptr, 0x20), salt)
            mstore(ptr, deployer) // Right-aligned with 12 preceding garbage bytes
            let start := add(ptr, 0x0b) // The hashed data starts at the final garbage byte which we will set to 0xff
            mstore8(start, 0xff)
            addr := keccak256(start, 85)
        }
    }
}


// File contracts/middleware/InterchainAccountRouter.sol


pragma solidity ^0.8.13;

// ============ Internal Imports ============




// ============ External Imports ============



/*
 * @title The Hello World App
 * @dev You can use this simple app as a starting point for your own application.
 */
contract InterchainAccountRouter is Router, IInterchainAccountRouter {
    address immutable implementation;
    bytes32 immutable bytecodeHash;

    event InterchainAccountCreated(
        uint32 indexed origin,
        address sender,
        address account
    );

    constructor() {
        implementation = address(new OwnableMulticall());
        // cannot be stored immutably because it is dynamically sized
        bytes memory bytecode = MinimalProxy.bytecode(implementation);
        bytecodeHash = keccak256(bytecode);
    }

    function initialize(
        address _mailbox,
        address _interchainGasPaymaster,
        address _interchainSecurityModule
    ) public initializer {
        // Transfer ownership of the contract to `msg.sender`
        __Router_initialize(
            _mailbox,
            _interchainGasPaymaster,
            _interchainSecurityModule
        );
    }

    function initialize(address _mailbox, address _interchainGasPaymaster)
        public
        initializer
    {
        // Transfer ownership of the contract to `msg.sender`
        __Router_initialize(_mailbox, _interchainGasPaymaster);
    }

    function dispatch(uint32 _destinationDomain, Call[] calldata calls)
        external
        returns (bytes32)
    {
        return _dispatch(_destinationDomain, abi.encode(msg.sender, calls));
    }

    function dispatch(
        uint32 _destinationDomain,
        address target,
        bytes calldata data
    ) external returns (bytes32) {
        Call[] memory calls = new Call[](1);
        calls[0] = Call({to: target, data: data});
        return _dispatch(_destinationDomain, abi.encode(msg.sender, calls));
    }

    function getInterchainAccount(uint32 _origin, address _sender)
        public
        view
        returns (address)
    {
        return _getInterchainAccount(_salt(_origin, _sender));
    }

    function getDeployedInterchainAccount(uint32 _origin, address _sender)
        public
        returns (OwnableMulticall)
    {
        bytes32 salt = _salt(_origin, _sender);
        address interchainAccount = _getInterchainAccount(salt);
        if (!Address.isContract(interchainAccount)) {
            bytes memory bytecode = MinimalProxy.bytecode(implementation);
            interchainAccount = Create2.deploy(0, salt, bytecode);
            OwnableMulticall(interchainAccount).initialize();
            emit InterchainAccountCreated(_origin, _sender, interchainAccount);
        }
        return OwnableMulticall(interchainAccount);
    }

    function _salt(uint32 _origin, address _sender)
        internal
        pure
        returns (bytes32)
    {
        return bytes32(abi.encodePacked(_origin, _sender));
    }

    function _getInterchainAccount(bytes32 salt)
        internal
        view
        returns (address)
    {
        return Create2.computeAddress(salt, bytecodeHash);
    }

    function _handle(
        uint32 _origin,
        bytes32, // router sender
        bytes calldata _message
    ) internal override {
        (address sender, Call[] memory calls) = abi.decode(
            _message,
            (address, Call[])
        );
        getDeployedInterchainAccount(_origin, sender).proxyCalls(calls);
    }
}


// File interfaces/IInterchainQueryRouter.sol


pragma solidity >=0.6.11;

interface IInterchainQueryRouter {
    function query(
        uint32 _destinationDomain,
        address target,
        bytes calldata queryData,
        bytes calldata callback
    ) external returns (bytes32);

    function query(
        uint32 _destinationDomain,
        Call calldata call,
        bytes calldata callback
    ) external returns (bytes32);

    function query(
        uint32 _destinationDomain,
        Call[] calldata calls,
        bytes[] calldata callbacks
    ) external returns (bytes32);
}


// File contracts/middleware/InterchainQueryRouter.sol


pragma solidity ^0.8.13;

// ============ Internal Imports ============



// ============ External Imports ============



contract InterchainQueryRouter is
    Router,
    OwnableMulticall,
    IInterchainQueryRouter
{
    enum Action {
        DISPATCH,
        RESOLVE
    }

    event QueryDispatched(
        uint32 indexed destinationDomain,
        address indexed sender
    );
    event QueryReturned(uint32 indexed originDomain, address indexed sender);
    event QueryResolved(
        uint32 indexed destinationDomain,
        address indexed sender
    );

    function initialize(
        address _mailbox,
        address _interchainGasPaymaster,
        address _interchainSecurityModule
    ) public initializer {
        // Transfer ownership of the contract to `msg.sender`
        __Router_initialize(
            _mailbox,
            _interchainGasPaymaster,
            _interchainSecurityModule
        );
    }

    function initialize(address _mailbox, address _interchainGasPaymaster)
        public
        initializer
    {
        // Transfer ownership of the contract to `msg.sender`
        __Router_initialize(_mailbox, _interchainGasPaymaster);
    }

    /**
     * @param _destinationDomain Domain of destination chain
     * @param target The address of the contract to query on destination chain.
     * @param queryData The calldata of the view call to make on the destination chain.
     * @param callback Callback function selector on `msg.sender` and optionally abi-encoded prefix arguments.
     */
    function query(
        uint32 _destinationDomain,
        address target,
        bytes calldata queryData,
        bytes calldata callback
    ) external returns (bytes32 messageId) {
        // TODO: fix this ugly arrayification
        Call[] memory calls = new Call[](1);
        calls[0] = Call({to: target, data: queryData});
        bytes[] memory callbacks = new bytes[](1);
        callbacks[0] = callback;
        messageId = query(_destinationDomain, calls, callbacks);
    }

    /**
     * @param _destinationDomain Domain of destination chain
     * @param call Call (to and data packed struct) to be made on destination chain.
     * @param callback Callback function selector on `msg.sender` and optionally abi-encoded prefix arguments.
     */
    function query(
        uint32 _destinationDomain,
        Call calldata call,
        bytes calldata callback
    ) external returns (bytes32 messageId) {
        // TODO: fix this ugly arrayification
        Call[] memory calls = new Call[](1);
        calls[0] = call;
        bytes[] memory callbacks = new bytes[](1);
        callbacks[0] = callback;
        messageId = query(_destinationDomain, calls, callbacks);
    }

    /**
     * @param _destinationDomain Domain of destination chain
     * @param calls Array of calls (to and data packed struct) to be made on destination chain in sequence.
     * @param callbacks Array of callback function selectors on `msg.sender` and optionally abi-encoded prefix arguments.
     */
    function query(
        uint32 _destinationDomain,
        Call[] memory calls,
        bytes[] memory callbacks
    ) public returns (bytes32 messageId) {
        require(
            calls.length == callbacks.length,
            "InterchainQueryRouter: calls and callbacks must be same length"
        );
        messageId = _dispatch(
            _destinationDomain,
            abi.encode(Action.DISPATCH, msg.sender, calls, callbacks)
        );
        emit QueryDispatched(_destinationDomain, msg.sender);
    }

    // TODO: add REJECT behavior ala NodeJS Promise API
    function _handle(
        uint32 _origin,
        bytes32, // router sender
        bytes calldata _message
    ) internal override {
        // TODO: fix double ABI decoding with calldata slices
        Action action = abi.decode(_message, (Action));
        if (action == Action.DISPATCH) {
            (
                ,
                address sender,
                Call[] memory calls,
                bytes[] memory callbacks
            ) = abi.decode(_message, (Action, address, Call[], bytes[]));
            bytes[] memory resolveCallbacks = _call(calls, callbacks);
            _dispatch(
                _origin,
                abi.encode(Action.RESOLVE, sender, resolveCallbacks)
            );
            emit QueryReturned(_origin, sender);
        } else if (action == Action.RESOLVE) {
            (, address sender, bytes[] memory resolveCallbacks) = abi.decode(
                _message,
                (Action, address, bytes[])
            );
            proxyCallBatch(sender, resolveCallbacks);
            emit QueryResolved(_origin, sender);
        }
    }
}


// File contracts/middleware/liquidity-layer/interfaces/circle/ICircleBridge.sol


pragma solidity ^0.8.13;

interface ICircleBridge {
    event MessageSent(bytes message);

    /**
     * @notice Deposits and burns tokens from sender to be minted on destination domain.
     * Emits a `DepositForBurn` event.
     * @dev reverts if:
     * - given burnToken is not supported
     * - given destinationDomain has no CircleBridge registered
     * - transferFrom() reverts. For example, if sender's burnToken balance or approved allowance
     * to this contract is less than `amount`.
     * - burn() reverts. For example, if `amount` is 0.
     * - MessageTransmitter returns false or reverts.
     * @param _amount amount of tokens to burn
     * @param _destinationDomain destination domain (ETH = 0, AVAX = 1)
     * @param _mintRecipient address of mint recipient on destination domain
     * @param _burnToken address of contract to burn deposited tokens, on local domain
     * @return _nonce unique nonce reserved by message
     */
    function depositForBurn(
        uint256 _amount,
        uint32 _destinationDomain,
        bytes32 _mintRecipient,
        address _burnToken
    ) external returns (uint64 _nonce);

    /**
     * @notice Deposits and burns tokens from sender to be minted on destination domain. The mint
     * on the destination domain must be called by `_destinationCaller`.
     * WARNING: if the `_destinationCaller` does not represent a valid address as bytes32, then it will not be possible
     * to broadcast the message on the destination domain. This is an advanced feature, and the standard
     * depositForBurn() should be preferred for use cases where a specific destination caller is not required.
     * Emits a `DepositForBurn` event.
     * @dev reverts if:
     * - given destinationCaller is zero address
     * - given burnToken is not supported
     * - given destinationDomain has no CircleBridge registered
     * - transferFrom() reverts. For example, if sender's burnToken balance or approved allowance
     * to this contract is less than `amount`.
     * - burn() reverts. For example, if `amount` is 0.
     * - MessageTransmitter returns false or reverts.
     * @param _amount amount of tokens to burn
     * @param _destinationDomain destination domain
     * @param _mintRecipient address of mint recipient on destination domain
     * @param _burnToken address of contract to burn deposited tokens, on local domain
     * @param _destinationCaller caller on the destination domain, as bytes32
     * @return _nonce unique nonce reserved by message
     */
    function depositForBurnWithCaller(
        uint256 _amount,
        uint32 _destinationDomain,
        bytes32 _mintRecipient,
        address _burnToken,
        bytes32 _destinationCaller
    ) external returns (uint64 _nonce);
}


// File contracts/middleware/liquidity-layer/interfaces/circle/ICircleMessageTransmitter.sol


pragma solidity ^0.8.13;

interface ICircleMessageTransmitter {
    /**
     * @notice Receive a message. Messages with a given nonce
     * can only be broadcast once for a (sourceDomain, destinationDomain)
     * pair. The message body of a valid message is passed to the
     * specified recipient for further processing.
     *
     * @dev Attestation format:
     * A valid attestation is the concatenated 65-byte signature(s) of exactly
     * `thresholdSignature` signatures, in increasing order of attester address.
     * ***If the attester addresses recovered from signatures are not in
     * increasing order, signature verification will fail.***
     * If incorrect number of signatures or duplicate signatures are supplied,
     * signature verification will fail.
     *
     * Message format:
     * Field Bytes Type Index
     * version 4 uint32 0
     * sourceDomain 4 uint32 4
     * destinationDomain 4 uint32 8
     * nonce 8 uint64 12
     * sender 32 bytes32 20
     * recipient 32 bytes32 52
     * messageBody dynamic bytes 84
     * @param _message Message bytes
     * @param _attestation Concatenated 65-byte signature(s) of `_message`, in increasing order
     * of the attester address recovered from signatures.
     * @return success bool, true if successful
     */
    function receiveMessage(bytes memory _message, bytes calldata _attestation)
        external
        returns (bool success);

    function usedNonces(bytes32 _nonceId) external view returns (bool);
}


// File contracts/middleware/liquidity-layer/interfaces/ILiquidityLayerAdapter.sol


pragma solidity ^0.8.13;

interface ILiquidityLayerAdapter {
    function sendTokens(
        uint32 _destinationDomain,
        bytes32 _recipientAddress,
        address _token,
        uint256 _amount
    ) external returns (bytes memory _adapterData);

    function receiveTokens(
        uint32 _originDomain, // Hyperlane domain
        address _recipientAddress,
        uint256 _amount,
        bytes calldata _adapterData // The adapter data from the message
    ) external returns (address, uint256);
}


// File @openzeppelin/contracts/token/ERC20/IERC20.sol@v4.8.0


// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);

    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `from` to `to` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) external returns (bool);
}


// File contracts/middleware/liquidity-layer/adapters/CircleBridgeAdapter.sol


pragma solidity ^0.8.13;



contract CircleBridgeAdapter is ILiquidityLayerAdapter, Router {
    /// @notice The CircleBridge contract.
    ICircleBridge public circleBridge;

    /// @notice The Circle MessageTransmitter contract.
    ICircleMessageTransmitter public circleMessageTransmitter;

    /// @notice The LiquidityLayerRouter contract.
    address public liquidityLayerRouter;

    /// @notice Hyperlane domain => Circle domain.
    /// ATM, known Circle domains are Ethereum = 0 and Avalanche = 1.
    /// Note this could result in ambiguity between the Circle domain being
    /// Ethereum or unknown. TODO fix?
    mapping(uint32 => uint32) public hyperlaneDomainToCircleDomain;

    /// @notice Token symbol => address of token on local chain.
    mapping(string => IERC20) public tokenSymbolToAddress;

    /// @notice Local chain token address => token symbol.
    mapping(address => string) public tokenAddressToSymbol;

    /**
     * @notice Emits the nonce of the Circle message when a token is bridged.
     * @param nonce The nonce of the Circle message.
     */
    event BridgedToken(uint64 nonce);

    /**
     * @notice Emitted when the Hyperlane domain to Circle domain mapping is updated.
     * @param hyperlaneDomain The Hyperlane domain.
     * @param circleDomain The Circle domain.
     */
    event DomainAdded(uint32 indexed hyperlaneDomain, uint32 circleDomain);

    /**
     * @notice Emitted when a local token and its token symbol have been added.
     */
    event TokenAdded(address indexed token, string indexed symbol);

    /**
     * @notice Emitted when a local token and its token symbol have been removed.
     */
    event TokenRemoved(address indexed token, string indexed symbol);

    modifier onlyLiquidityLayerRouter() {
        require(msg.sender == liquidityLayerRouter, "!liquidityLayerRouter");
        _;
    }

    /**
     * @param _owner The new owner.
     * @param _circleBridge The CircleBridge contract.
     * @param _circleMessageTransmitter The Circle MessageTransmitter contract.
     * @param _liquidityLayerRouter The LiquidityLayerRouter contract.
     */
    function initialize(
        address _owner,
        address _circleBridge,
        address _circleMessageTransmitter,
        address _liquidityLayerRouter
    ) public initializer {
        // Transfer ownership of the contract to deployer
        _transferOwnership(_owner);

        circleBridge = ICircleBridge(_circleBridge);
        circleMessageTransmitter = ICircleMessageTransmitter(
            _circleMessageTransmitter
        );
        liquidityLayerRouter = _liquidityLayerRouter;
    }

    function sendTokens(
        uint32 _destinationDomain,
        bytes32, // _recipientAddress, unused
        address _token,
        uint256 _amount
    ) external onlyLiquidityLayerRouter returns (bytes memory) {
        string memory _tokenSymbol = tokenAddressToSymbol[_token];
        require(
            bytes(_tokenSymbol).length > 0,
            "CircleBridgeAdapter: Unknown token"
        );

        uint32 _circleDomain = hyperlaneDomainToCircleDomain[
            _destinationDomain
        ];
        bytes32 _remoteRouter = routers(_destinationDomain);
        require(
            _remoteRouter != bytes32(0),
            "CircleBridgeAdapter: No router for domain"
        );

        // Approve the token to Circle. We assume that the LiquidityLayerRouter
        // has already transferred the token to this contract.
        require(
            IERC20(_token).approve(address(circleBridge), _amount),
            "!approval"
        );

        uint64 _nonce = circleBridge.depositForBurn(
            _amount,
            _circleDomain,
            _remoteRouter, // Mint to the remote router
            _token
        );

        emit BridgedToken(_nonce);
        return abi.encode(_nonce, _tokenSymbol);
    }

    // Returns the token and amount sent
    function receiveTokens(
        uint32 _originDomain, // Hyperlane domain
        address _recipient,
        uint256 _amount,
        bytes calldata _adapterData // The adapter data from the message
    ) external onlyLiquidityLayerRouter returns (address, uint256) {
        // The origin Circle domain
        uint32 _originCircleDomain = hyperlaneDomainToCircleDomain[
            _originDomain
        ];
        // Get the token symbol and nonce of the transfer from the _adapterData
        (uint64 _nonce, string memory _tokenSymbol) = abi.decode(
            _adapterData,
            (uint64, string)
        );

        // Require the circle message to have been processed
        bytes32 _nonceId = _circleNonceId(_originCircleDomain, _nonce);
        require(
            circleMessageTransmitter.usedNonces(_nonceId),
            "Circle message not processed yet"
        );

        IERC20 _token = tokenSymbolToAddress[_tokenSymbol];
        require(
            address(_token) != address(0),
            "CircleBridgeAdapter: Unknown token"
        );

        // Transfer the token out to the recipient
        // TODO: use safeTransfer
        // Circle doesn't charge any fee, so we can safely transfer out the
        // exact amount that was bridged over.
        require(_token.transfer(_recipient, _amount), "!transfer out");

        return (address(_token), _amount);
    }

    // This contract is only a Router to be aware of remote router addresses,
    // and doesn't actually send/handle Hyperlane messages directly
    function _handle(
        uint32, // origin
        bytes32, // sender
        bytes calldata // message
    ) internal pure override {
        revert("No messages expected");
    }

    function addDomain(uint32 _hyperlaneDomain, uint32 _circleDomain)
        external
        onlyOwner
    {
        hyperlaneDomainToCircleDomain[_hyperlaneDomain] = _circleDomain;

        emit DomainAdded(_hyperlaneDomain, _circleDomain);
    }

    function addToken(address _token, string calldata _tokenSymbol)
        external
        onlyOwner
    {
        require(
            _token != address(0) && bytes(_tokenSymbol).length > 0,
            "Cannot add default values"
        );

        // Require the token and token symbol to be unset.
        address _existingToken = address(tokenSymbolToAddress[_tokenSymbol]);
        require(_existingToken == address(0), "token symbol already has token");

        string memory _existingSymbol = tokenAddressToSymbol[_token];
        require(
            bytes(_existingSymbol).length == 0,
            "token already has token symbol"
        );

        tokenAddressToSymbol[_token] = _tokenSymbol;
        tokenSymbolToAddress[_tokenSymbol] = IERC20(_token);

        emit TokenAdded(_token, _tokenSymbol);
    }

    function removeToken(address _token, string calldata _tokenSymbol)
        external
        onlyOwner
    {
        // Require the provided token and token symbols match what's in storage.
        address _existingToken = address(tokenSymbolToAddress[_tokenSymbol]);
        require(_existingToken == _token, "Token mismatch");

        string memory _existingSymbol = tokenAddressToSymbol[_token];
        require(
            keccak256(bytes(_existingSymbol)) == keccak256(bytes(_tokenSymbol)),
            "Token symbol mismatch"
        );

        // Delete them from storage.
        delete tokenSymbolToAddress[_tokenSymbol];
        delete tokenAddressToSymbol[_token];

        emit TokenRemoved(_token, _tokenSymbol);
    }

    /**
     * @notice Gets the Circle nonce ID by hashing _originCircleDomain and _nonce.
     * @param _originCircleDomain Domain of chain where the transfer originated
     * @param _nonce The unique identifier for the message from source to
              destination
     * @return hash of source and nonce
     */
    function _circleNonceId(uint32 _originCircleDomain, uint64 _nonce)
        internal
        pure
        returns (bytes32)
    {
        // The hash is of a uint256 nonce, not a uint64 one.
        return
            keccak256(abi.encodePacked(_originCircleDomain, uint256(_nonce)));
    }
}


// File interfaces/ILiquidityLayerRouter.sol


pragma solidity >=0.6.11;

interface ILiquidityLayerRouter {
    function dispatchWithTokens(
        uint32 _destinationDomain,
        bytes32 _recipientAddress,
        bytes calldata _messageBody,
        address _token,
        uint256 _amount,
        string calldata _bridge
    ) external payable returns (bytes32);
}


// File interfaces/ILiquidityLayerMessageRecipient.sol


pragma solidity ^0.8.13;

interface ILiquidityLayerMessageRecipient {
    function handleWithTokens(
        uint32 _origin,
        bytes32 _sender,
        bytes calldata _message,
        address _token,
        uint256 _amount
    ) external;
}


// File contracts/middleware/liquidity-layer/LiquidityLayerRouter.sol


pragma solidity ^0.8.13;





contract LiquidityLayerRouter is Router, ILiquidityLayerRouter {
    // Token bridge => adapter address
    mapping(string => address) public liquidityLayerAdapters;

    event LiquidityLayerAdapterSet(string indexed bridge, address adapter);

    function initialize(
        address _mailbox,
        address _interchainGasPaymaster,
        address _interchainSecurityModule
    ) public initializer {
        // Transfer ownership of the contract to `msg.sender`
        __Router_initialize(
            _mailbox,
            _interchainGasPaymaster,
            _interchainSecurityModule
        );
    }

    function initialize(address _mailbox, address _interchainGasPaymaster)
        public
        initializer
    {
        // Transfer ownership of the contract to `msg.sender`
        __Router_initialize(_mailbox, _interchainGasPaymaster);
    }

    function dispatchWithTokens(
        uint32 _destinationDomain,
        bytes32 _recipientAddress,
        bytes calldata _messageBody,
        address _token,
        uint256 _amount,
        string calldata _bridge
    ) external payable returns (bytes32) {
        ILiquidityLayerAdapter _adapter = _getAdapter(_bridge);

        // Transfer the tokens to the adapter
        // TODO: use safeTransferFrom
        // TODO: Are there scenarios where a transferFrom fails and it doesn't revert?
        require(
            IERC20(_token).transferFrom(msg.sender, address(_adapter), _amount),
            "!transfer in"
        );

        // Reverts if the bridge was unsuccessful.
        // Gets adapter-specific data that is encoded into the message
        // ultimately sent via Hyperlane.
        bytes memory _adapterData = _adapter.sendTokens(
            _destinationDomain,
            _recipientAddress,
            _token,
            _amount
        );

        // The user's message "wrapped" with metadata required by this middleware
        bytes memory _messageWithMetadata = abi.encode(
            TypeCasts.addressToBytes32(msg.sender),
            _recipientAddress, // The "user" recipient
            _amount, // The amount of the tokens sent over the bridge
            _bridge, // The destination token bridge ID
            _adapterData, // The adapter-specific data
            _messageBody // The "user" message
        );

        // Dispatch the _messageWithMetadata to the destination's LiquidityLayerRouter.
        return
            _dispatchWithGas(
                _destinationDomain,
                _messageWithMetadata,
                0, // TODO eventually accommodate gas amounts
                msg.value,
                msg.sender
            );
    }

    // Handles a message from an enrolled remote LiquidityLayerRouter
    function _handle(
        uint32 _origin,
        bytes32, // _sender, unused
        bytes calldata _message
    ) internal override {
        // Decode the message with metadata, "unwrapping" the user's message body
        (
            bytes32 _originalSender,
            bytes32 _userRecipientAddress,
            uint256 _amount,
            string memory _bridge,
            bytes memory _adapterData,
            bytes memory _userMessageBody
        ) = abi.decode(
                _message,
                (bytes32, bytes32, uint256, string, bytes, bytes)
            );

        ILiquidityLayerMessageRecipient _userRecipient = ILiquidityLayerMessageRecipient(
                TypeCasts.bytes32ToAddress(_userRecipientAddress)
            );

        // Reverts if the adapter hasn't received the bridged tokens yet
        (address _token, uint256 _receivedAmount) = _getAdapter(_bridge)
            .receiveTokens(
                _origin,
                address(_userRecipient),
                _amount,
                _adapterData
            );

        _userRecipient.handleWithTokens(
            _origin,
            _originalSender,
            _userMessageBody,
            _token,
            _receivedAmount
        );
    }

    function setLiquidityLayerAdapter(string calldata _bridge, address _adapter)
        external
        onlyOwner
    {
        liquidityLayerAdapters[_bridge] = _adapter;
        emit LiquidityLayerAdapterSet(_bridge, _adapter);
    }

    function _getAdapter(string memory _bridge)
        internal
        view
        returns (ILiquidityLayerAdapter _adapter)
    {
        _adapter = ILiquidityLayerAdapter(liquidityLayerAdapters[_bridge]);
        // Require the adapter to have been set
        require(address(_adapter) != address(0), "No adapter found for bridge");
    }
}


// File @openzeppelin/contracts-upgradeable/token/ERC20/IERC20Upgradeable.sol@v4.8.0


// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20Upgradeable {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);

    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `from` to `to` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) external returns (bool);
}


// File @openzeppelin/contracts-upgradeable/token/ERC20/extensions/IERC20MetadataUpgradeable.sol@v4.8.0


// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
interface IERC20MetadataUpgradeable is IERC20Upgradeable {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the symbol of the token.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}


// File @openzeppelin/contracts-upgradeable/token/ERC20/ERC20Upgradeable.sol@v4.8.0


// OpenZeppelin Contracts (last updated v4.8.0) (token/ERC20/ERC20.sol)

pragma solidity ^0.8.0;




/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.openzeppelin.com/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin Contracts guidelines: functions revert
 * instead returning `false` on failure. This behavior is nonetheless
 * conventional and does not conflict with the expectations of ERC20
 * applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20Upgradeable is Initializable, ContextUpgradeable, IERC20Upgradeable, IERC20MetadataUpgradeable {
    mapping(address => uint256) private _balances;

    mapping(address => mapping(address => uint256)) private _allowances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;

    /**
     * @dev Sets the values for {name} and {symbol}.
     *
     * The default value of {decimals} is 18. To select a different value for
     * {decimals} you should overload it.
     *
     * All two of these values are immutable: they can only be set once during
     * construction.
     */
    function __ERC20_init(string memory name_, string memory symbol_) internal onlyInitializing {
        __ERC20_init_unchained(name_, symbol_);
    }

    function __ERC20_init_unchained(string memory name_, string memory symbol_) internal onlyInitializing {
        _name = name_;
        _symbol = symbol_;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5.05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the value {ERC20} uses, unless this function is
     * overridden;
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view virtual override returns (uint8) {
        return 18;
    }

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view virtual override returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address to, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _transfer(owner, to, amount);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on
     * `transferFrom`. This is semantically equivalent to an infinite approval.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20}.
     *
     * NOTE: Does not update the allowance if the current allowance
     * is the maximum `uint256`.
     *
     * Requirements:
     *
     * - `from` and `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     * - the caller must have allowance for ``from``'s tokens of at least
     * `amount`.
     */
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) public virtual override returns (bool) {
        address spender = _msgSender();
        _spendAllowance(from, spender, amount);
        _transfer(from, to, amount);
        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, allowance(owner, spender) + addedValue);
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        address owner = _msgSender();
        uint256 currentAllowance = allowance(owner, spender);
        require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
        unchecked {
            _approve(owner, spender, currentAllowance - subtractedValue);
        }

        return true;
    }

    /**
     * @dev Moves `amount` of tokens from `from` to `to`.
     *
     * This internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     */
    function _transfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(from, to, amount);

        uint256 fromBalance = _balances[from];
        require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
        unchecked {
            _balances[from] = fromBalance - amount;
            // Overflow not possible: the sum of all balances is capped by totalSupply, and the sum is preserved by
            // decrementing then incrementing.
            _balances[to] += amount;
        }

        emit Transfer(from, to, amount);

        _afterTokenTransfer(from, to, amount);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply += amount;
        unchecked {
            // Overflow not possible: balance + amount is at most totalSupply + amount, which is checked above.
            _balances[account] += amount;
        }
        emit Transfer(address(0), account, amount);

        _afterTokenTransfer(address(0), account, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        unchecked {
            _balances[account] = accountBalance - amount;
            // Overflow not possible: amount <= accountBalance <= totalSupply.
            _totalSupply -= amount;
        }

        emit Transfer(account, address(0), amount);

        _afterTokenTransfer(account, address(0), amount);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
     *
     * This internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    /**
     * @dev Updates `owner` s allowance for `spender` based on spent `amount`.
     *
     * Does not update the allowance amount in case of infinite allowance.
     * Revert if not enough allowance is available.
     *
     * Might emit an {Approval} event.
     */
    function _spendAllowance(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        uint256 currentAllowance = allowance(owner, spender);
        if (currentAllowance != type(uint256).max) {
            require(currentAllowance >= amount, "ERC20: insufficient allowance");
            unchecked {
                _approve(owner, spender, currentAllowance - amount);
            }
        }
    }

    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}

    /**
     * @dev Hook that is called after any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * has been transferred to `to`.
     * - when `from` is zero, `amount` tokens have been minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens have been burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _afterTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[45] private __gap;
}


// File contracts/mock/MockToken.sol


pragma solidity ^0.8.13;

contract MockToken is ERC20Upgradeable {
    function mint(address account, uint256 amount) external {
        _mint(account, amount);
    }

    function burn(uint256 _amount) external {
        _burn(msg.sender, _amount);
    }
}


// File contracts/mock/MockCircleBridge.sol


pragma solidity ^0.8.13;


contract MockCircleBridge is ICircleBridge {
    uint64 public nextNonce = 0;
    MockToken token;

    constructor(MockToken _token) {
        token = _token;
    }

    function depositForBurn(
        uint256 _amount,
        uint32,
        bytes32,
        address _burnToken
    ) external returns (uint64 _nonce) {
        nextNonce = nextNonce + 1;
        _nonce = nextNonce;
        require(address(token) == _burnToken);
        token.transferFrom(msg.sender, address(this), _amount);
        token.burn(_amount);
    }

    function depositForBurnWithCaller(
        uint256,
        uint32,
        bytes32,
        address,
        bytes32
    ) external returns (uint64 _nonce) {
        nextNonce = nextNonce + 1;
        _nonce = nextNonce;
    }
}


// File contracts/mock/MockCircleMessageTransmitter.sol


pragma solidity ^0.8.13;


contract MockCircleMessageTransmitter is ICircleMessageTransmitter {
    mapping(bytes32 => bool) processedNonces;
    MockToken token;

    constructor(MockToken _token) {
        token = _token;
    }

    function receiveMessage(bytes memory, bytes calldata)
        external
        pure
        returns (bool success)
    {
        success = true;
    }

    function hashSourceAndNonce(uint32 _source, uint256 _nonce)
        public
        pure
        returns (bytes32)
    {
        return keccak256(abi.encodePacked(_source, _nonce));
    }

    function process(
        bytes32 _nonceId,
        address _recipient,
        uint256 _amount
    ) public {
        processedNonces[_nonceId] = true;
        token.mint(_recipient, _amount);
    }

    function usedNonces(bytes32 _nonceId) external view returns (bool) {
        return processedNonces[_nonceId];
    }
}


// File contracts/mock/MockMailbox.sol


pragma solidity ^0.8.0;


contract MockMailbox {
    using TypeCasts for address;
    using TypeCasts for bytes32;
    // Domain of chain on which the contract is deployed
    uint32 public immutable domain;
    uint32 public immutable version = 0;

    uint256 public outboundNonce = 0;
    uint256 public inboundUnprocessedNonce = 0;
    uint256 public inboundProcessedNonce = 0;
    mapping(uint32 => MockMailbox) public remoteMailboxes;
    mapping(uint256 => Message) public inboundMessages;

    struct Message {
        uint32 origin;
        address sender;
        address recipient;
        bytes body;
    }

    constructor(uint32 _domain) {
        domain = _domain;
    }

    function addRemoteMailbox(uint32 _domain, MockMailbox _mailbox) external {
        remoteMailboxes[_domain] = _mailbox;
    }

    function dispatch(
        uint32 _destinationDomain,
        bytes32 _recipientAddress,
        bytes calldata _messageBody
    ) external returns (bytes32) {
        MockMailbox _destinationMailbox = remoteMailboxes[_destinationDomain];
        require(
            address(_destinationMailbox) != address(0),
            "Missing remote mailbox"
        );
        _destinationMailbox.addInboundMessage(
            domain,
            msg.sender,
            _recipientAddress.bytes32ToAddress(),
            _messageBody
        );
        outboundNonce++;
        return bytes32(0);
    }

    function addInboundMessage(
        uint32 _origin,
        address _sender,
        address _recipient,
        bytes calldata _body
    ) external {
        inboundMessages[inboundUnprocessedNonce] = Message(
            _origin,
            _sender,
            _recipient,
            _body
        );
        inboundUnprocessedNonce++;
    }

    function processNextInboundMessage() public {
        Message memory _message = inboundMessages[inboundProcessedNonce];
        IMessageRecipient(_message.recipient).handle(
            _message.origin,
            _message.sender.addressToBytes32(),
            _message.body
        );
        inboundProcessedNonce++;
    }
}


// File contracts/test/TestIsm.sol


pragma solidity >=0.8.0;

contract TestIsm is IInterchainSecurityModule {
    uint8 public constant moduleType = 0;
    bool public accept;

    function setAccept(bool _val) external {
        accept = _val;
    }

    function verify(bytes calldata, bytes calldata)
        external
        view
        returns (bool)
    {
        return accept;
    }
}


// File contracts/mock/MockHyperlaneEnvironment.sol


pragma solidity ^0.8.13;




contract MockHyperlaneEnvironment {
    uint32 originDomain;
    uint32 destinationDomain;

    mapping(uint32 => MockMailbox) public mailboxes;
    mapping(uint32 => InterchainGasPaymaster) public igps;
    mapping(uint32 => IInterchainSecurityModule) public isms;
    mapping(uint32 => InterchainQueryRouter) public queryRouters;

    constructor(uint32 _originDomain, uint32 _destinationDomain) {
        originDomain = _originDomain;
        destinationDomain = _destinationDomain;

        MockMailbox originMailbox = new MockMailbox(_originDomain);
        MockMailbox destinationMailbox = new MockMailbox(_destinationDomain);

        originMailbox.addRemoteMailbox(_destinationDomain, destinationMailbox);
        destinationMailbox.addRemoteMailbox(_originDomain, originMailbox);

        igps[originDomain] = new InterchainGasPaymaster();
        igps[destinationDomain] = new InterchainGasPaymaster();

        isms[originDomain] = new TestIsm();
        isms[destinationDomain] = new TestIsm();

        mailboxes[_originDomain] = originMailbox;
        mailboxes[_destinationDomain] = destinationMailbox;

        InterchainQueryRouter originQueryRouter = new InterchainQueryRouter();
        InterchainQueryRouter destinationQueryRouter = new InterchainQueryRouter();

        originQueryRouter.initialize(
            address(originMailbox),
            address(igps[originDomain]),
            address(isms[originDomain])
        );
        destinationQueryRouter.initialize(
            address(destinationMailbox),
            address(igps[destinationDomain]),
            address(isms[destinationDomain])
        );

        originQueryRouter.enrollRemoteRouter(
            _destinationDomain,
            TypeCasts.addressToBytes32(address(destinationQueryRouter))
        );
        destinationQueryRouter.enrollRemoteRouter(
            _originDomain,
            TypeCasts.addressToBytes32(address(originQueryRouter))
        );

        queryRouters[_originDomain] = originQueryRouter;
        queryRouters[_destinationDomain] = destinationQueryRouter;
    }

    function processNextPendingMessage() public {
        mailboxes[destinationDomain].processNextInboundMessage();
    }

    function processNextPendingMessageFromDestination() public {
        mailboxes[originDomain].processNextInboundMessage();
    }
}


// File contracts/mock/MockInterchainAccountRouter.sol


pragma solidity ^0.8.13;


/*
 * @title The Hello World App
 * @dev You can use this simple app as a starting point for your own application.
 */
contract MockInterchainAccountRouter is InterchainAccountRouter {
    struct PendingCall {
        uint32 originDomain;
        bytes senderAndCalls;
    }

    uint32 public originDomain;

    mapping(uint256 => PendingCall) pendingCalls;
    uint256 totalCalls = 0;
    uint256 callsProcessed = 0;

    constructor(uint32 _originDomain) InterchainAccountRouter() {
        originDomain = _originDomain;
    }

    function _dispatch(uint32, bytes memory _messageBody)
        internal
        override
        returns (bytes32)
    {
        pendingCalls[totalCalls] = PendingCall(originDomain, _messageBody);
        totalCalls += 1;
        return keccak256(abi.encodePacked(totalCalls));
    }

    function processNextPendingCall() public {
        PendingCall memory pendingCall = pendingCalls[callsProcessed];
        (address sender, Call[] memory calls) = abi.decode(
            pendingCall.senderAndCalls,
            (address, Call[])
        );

        getDeployedInterchainAccount(originDomain, sender).proxyCalls(calls);

        callsProcessed += 1;
    }
}


// File contracts/test/bad-recipient/BadRecipient1.sol


pragma solidity >=0.8.0;

contract BadRecipient1 is IMessageRecipient {
    function handle(
        uint32,
        bytes32,
        bytes calldata
    ) external pure override {
        assembly {
            revert(0, 0)
        }
    }
}


// File contracts/test/bad-recipient/BadRecipient3.sol


pragma solidity >=0.8.0;

contract BadRecipient3 is IMessageRecipient {
    function handle(
        uint32,
        bytes32,
        bytes calldata
    ) external pure override {
        assembly {
            mstore(0, 0xabcdef)
            revert(0, 32)
        }
    }
}


// File contracts/test/bad-recipient/BadRecipient5.sol


pragma solidity >=0.8.0;

contract BadRecipient5 is IMessageRecipient {
    function handle(
        uint32,
        bytes32,
        bytes calldata
    ) external pure override {
        require(false, "no can do");
    }
}


// File contracts/test/bad-recipient/BadRecipient6.sol


pragma solidity >=0.8.0;

contract BadRecipient6 is IMessageRecipient {
    function handle(
        uint32,
        bytes32,
        bytes calldata
    ) external pure override {
        require(false); // solhint-disable-line reason-string
    }
}


// File contracts/test/TestHyperlaneConnectionClient.sol


pragma solidity >=0.6.11;


contract TestHyperlaneConnectionClient is HyperlaneConnectionClient {
    function initialize(address _mailbox) external initializer {
        __HyperlaneConnectionClient_initialize(_mailbox);
    }

    function localDomain() external view returns (uint32) {
        return mailbox.localDomain();
    }
}


// File contracts/test/TestLiquidityLayerMessageRecipient.sol


pragma solidity ^0.8.13;

contract TestLiquidityLayerMessageRecipient is ILiquidityLayerMessageRecipient {
    event HandledWithTokens(
        uint32 origin,
        bytes32 sender,
        bytes message,
        address token,
        uint256 amount
    );

    function handleWithTokens(
        uint32 _origin,
        bytes32 _sender,
        bytes calldata _message,
        address _token,
        uint256 _amount
    ) external {
        emit HandledWithTokens(_origin, _sender, _message, _token, _amount);
    }
}


// File contracts/test/TestMailbox.sol


pragma solidity >=0.8.0;




contract TestMailbox is Mailbox {
    using TypeCasts for bytes32;

    constructor(uint32 _localDomain) Mailbox(_localDomain) {} // solhint-disable-line no-empty-blocks

    function proof() external view returns (bytes32[32] memory) {
        bytes32[32] memory _zeroes = MerkleLib.zeroHashes();
        uint256 _index = tree.count - 1;
        bytes32[32] memory _proof;

        for (uint256 i = 0; i < 32; i++) {
            uint256 _ithBit = (_index >> i) & 0x01;
            if (_ithBit == 1) {
                _proof[i] = tree.branch[i];
            } else {
                _proof[i] = _zeroes[i];
            }
        }
        return _proof;
    }

    function testHandle(
        uint32 _origin,
        bytes32 _sender,
        bytes32 _recipient,
        bytes calldata _body
    ) external {
        IMessageRecipient(_recipient.bytes32ToAddress()).handle(
            _origin,
            _sender,
            _body
        );
    }
}


// File contracts/test/TestMerkle.sol


pragma solidity >=0.8.0;

contract TestMerkle {
    using MerkleLib for MerkleLib.Tree;

    MerkleLib.Tree public tree;

    // solhint-disable-next-line no-empty-blocks
    constructor() {}

    function insert(bytes32 _node) external {
        tree.insert(_node);
    }

    function branchRoot(
        bytes32 _leaf,
        bytes32[32] calldata _proof,
        uint256 _index
    ) external pure returns (bytes32 _node) {
        return MerkleLib.branchRoot(_leaf, _proof, _index);
    }

    /**
     * @notice Returns the number of inserted leaves in the tree
     */
    function count() public view returns (uint256) {
        return tree.count;
    }

    function root() public view returns (bytes32) {
        return tree.root();
    }
}


// File contracts/test/TestMessage.sol


pragma solidity >=0.6.11;

contract TestMessage {
    using Message for bytes;

    function version(bytes calldata _message)
        external
        pure
        returns (uint32 _version)
    {
        return _message.version();
    }

    function nonce(bytes calldata _message)
        external
        pure
        returns (uint256 _nonce)
    {
        return _message.nonce();
    }

    function body(bytes calldata _message)
        external
        pure
        returns (bytes calldata _body)
    {
        return _message.body();
    }

    function origin(bytes calldata _message)
        external
        pure
        returns (uint32 _origin)
    {
        return _message.origin();
    }

    function sender(bytes calldata _message)
        external
        pure
        returns (bytes32 _sender)
    {
        return _message.sender();
    }

    function destination(bytes calldata _message)
        external
        pure
        returns (uint32 _destination)
    {
        return _message.destination();
    }

    function recipient(bytes calldata _message)
        external
        pure
        returns (bytes32 _recipient)
    {
        return _message.recipient();
    }

    function recipientAddress(bytes calldata _message)
        external
        pure
        returns (address _recipient)
    {
        return _message.recipientAddress();
    }

    function id(bytes calldata _message) external pure returns (bytes32) {
        return _message.id();
    }
}


// File contracts/test/TestMultisigIsm.sol


pragma solidity >=0.8.0;

// ============ Internal Imports ============

contract TestMultisigIsm is MultisigIsm {
    function getDomainHash(uint32 _origin, bytes32 _originMailbox)
        external
        pure
        returns (bytes32)
    {
        return _getDomainHash(_origin, _originMailbox);
    }

    function getCheckpointDigest(bytes calldata _metadata, uint32 _origin)
        external
        pure
        returns (bytes32)
    {
        return _getCheckpointDigest(_metadata, _origin);
    }
}


// File contracts/test/TestQuery.sol


pragma solidity ^0.8.13;



contract TestQuery {
    InterchainQueryRouter public router;

    event Owner(uint256, address);

    constructor(address _router) {
        router = InterchainQueryRouter(_router);
    }

    /**
     * @dev Fetches owner of InterchainQueryRouter on provided domain and passes along with provided secret to `this.receiveRouterOwner`
     */
    function queryRouterOwner(uint32 domain, uint256 secret) external {
        Call memory call = Call({
            to: TypeCasts.bytes32ToAddress(router.routers(domain)),
            data: abi.encodeWithSignature("owner()")
        });
        bytes memory callback = bytes.concat(
            this.receiveRouterOwer.selector,
            bytes32(secret)
        );
        router.query(domain, call, callback);
    }

    /**
     * @dev `msg.sender` must be restricted to `this.router` to prevent any local account from spoofing query data.
     */
    function receiveRouterOwer(uint256 secret, address owner) external {
        require(msg.sender == address(router), "TestQuery: not from router");
        emit Owner(secret, owner);
    }
}


// File contracts/test/TestQuerySender.sol


pragma solidity >=0.8.0;


contract TestQuerySender is Initializable {
    IInterchainQueryRouter queryRouter;

    address public lastAddressResult;
    uint256 public lastUint256Result;
    bytes32 public lastBytes32Result;

    event ReceivedAddressResult(address result);
    event ReceivedUint256Result(uint256 result);
    event ReceivedBytes32Result(bytes32 result);

    function initialize(address _queryRouterAddress) public initializer {
        queryRouter = IInterchainQueryRouter(_queryRouterAddress);
    }

    function queryAddress(
        uint32 _destinationDomain,
        address _target,
        bytes calldata _targetData
    ) public {
        queryRouter.query(
            _destinationDomain,
            Call({to: _target, data: _targetData}),
            abi.encodePacked(this.handleQueryAddressResult.selector)
        );
    }

    function handleQueryAddressResult(address _result) public {
        emit ReceivedAddressResult(_result);
        lastAddressResult = _result;
    }

    function queryUint256(
        uint32 _destinationDomain,
        address _target,
        bytes calldata _targetData
    ) public {
        queryRouter.query(
            _destinationDomain,
            Call({to: _target, data: _targetData}),
            abi.encodePacked(this.handleQueryUint256Result.selector)
        );
    }

    function handleQueryUint256Result(uint256 _result) public {
        emit ReceivedUint256Result(_result);
        lastUint256Result = _result;
    }

    function queryBytes32(
        uint32 _destinationDomain,
        address _target,
        bytes calldata _targetData
    ) public {
        queryRouter.query(
            _destinationDomain,
            Call({to: _target, data: _targetData}),
            abi.encodePacked(this.handleQueryBytes32Result.selector)
        );
    }

    function handleQueryBytes32Result(bytes32 _result) public {
        emit ReceivedBytes32Result(_result);
        lastBytes32Result = _result;
    }
}


// File contracts/test/TestRecipient.sol


pragma solidity >=0.8.0;


contract TestRecipient is
    IMessageRecipient,
    ISpecifiesInterchainSecurityModule
{
    IInterchainSecurityModule public interchainSecurityModule;
    bytes32 public lastSender;
    bytes public lastData;

    address public lastCaller;
    string public lastCallMessage;

    event ReceivedMessage(
        uint32 indexed origin,
        bytes32 indexed sender,
        string message
    );

    event ReceivedCall(address indexed caller, uint256 amount, string message);

    function setInterchainSecurityModule(address _ism) external {
        interchainSecurityModule = IInterchainSecurityModule(_ism);
    }

    function handle(
        uint32 _origin,
        bytes32 _sender,
        bytes calldata _data
    ) external override {
        emit ReceivedMessage(_origin, _sender, string(_data));
        lastSender = _sender;
        lastData = _data;
    }

    function fooBar(uint256 amount, string calldata message) external {
        emit ReceivedCall(msg.sender, amount, message);
        lastCaller = msg.sender;
        lastCallMessage = message;
    }
}


// File contracts/test/TestRouter.sol


pragma solidity >=0.6.11;

contract TestRouter is Router {
    event InitializeOverload();

    function initialize(address _mailbox) external initializer {
        __Router_initialize(_mailbox);
        emit InitializeOverload();
    }

    function _handle(
        uint32,
        bytes32,
        bytes calldata
    ) internal pure override {}

    function isRemoteRouter(uint32 _domain, bytes32 _potentialRemoteRouter)
        external
        view
        returns (bool)
    {
        return _isRemoteRouter(_domain, _potentialRemoteRouter);
    }

    function mustHaveRemoteRouter(uint32 _domain)
        external
        view
        returns (bytes32)
    {
        return _mustHaveRemoteRouter(_domain);
    }

    function dispatch(uint32 _destination, bytes memory _msg) external {
        _dispatch(_destination, _msg);
    }

    function dispatchWithGas(
        uint32 _destinationDomain,
        bytes memory _messageBody,
        uint256 _gasAmount,
        uint256 _gasPayment,
        address _gasPaymentRefundAddress
    ) external payable {
        _dispatchWithGas(
            _destinationDomain,
            _messageBody,
            _gasAmount,
            _gasPayment,
            _gasPaymentRefundAddress
        );
    }
}


// File contracts/test/TestSendReceiver.sol


pragma solidity >=0.8.0;



contract TestSendReceiver is IMessageRecipient {
    using TypeCasts for address;

    uint256 public constant HANDLE_GAS_AMOUNT = 50_000;

    event Handled(bytes32 blockHash);

    function dispatchToSelf(
        IMailbox _mailbox,
        IInterchainGasPaymaster _paymaster,
        uint32 _destinationDomain,
        bytes calldata _messageBody
    ) external payable {
        bytes32 _messageId = _mailbox.dispatch(
            _destinationDomain,
            address(this).addressToBytes32(),
            _messageBody
        );
        uint256 _blockHashNum = uint256(previousBlockHash());
        uint256 _value = msg.value;
        if (_blockHashNum % 5 == 0) {
            // Pay in two separate calls, resulting in 2 distinct events
            uint256 _halfPayment = _value / 2;
            uint256 _halfGasAmount = HANDLE_GAS_AMOUNT / 2;
            _paymaster.payForGas{value: _halfPayment}(
                _messageId,
                _destinationDomain,
                _halfGasAmount,
                msg.sender
            );
            _paymaster.payForGas{value: _value - _halfPayment}(
                _messageId,
                _destinationDomain,
                HANDLE_GAS_AMOUNT - _halfGasAmount,
                msg.sender
            );
        } else {
            // Pay the entire msg.value in one call
            _paymaster.payForGas{value: _value}(
                _messageId,
                _destinationDomain,
                HANDLE_GAS_AMOUNT,
                msg.sender
            );
        }
    }

    function handle(
        uint32,
        bytes32,
        bytes calldata
    ) external override {
        bytes32 blockHash = previousBlockHash();
        bool isBlockHashEven = uint256(blockHash) % 2 == 0;
        require(isBlockHashEven, "block hash is odd");
        emit Handled(blockHash);
    }

    function previousBlockHash() internal view returns (bytes32) {
        return blockhash(block.number - 1);
    }
}


// File contracts/test/TestTokenRecipient.sol


pragma solidity >=0.8.0;

contract TestTokenRecipient is ILiquidityLayerMessageRecipient {
    bytes32 public lastSender;
    bytes public lastData;
    address public lastToken;
    uint256 public lastAmount;

    address public lastCaller;
    string public lastCallMessage;

    event ReceivedMessage(
        uint32 indexed origin,
        bytes32 indexed sender,
        string message,
        address token,
        uint256 amount
    );

    event ReceivedCall(address indexed caller, uint256 amount, string message);

    function handleWithTokens(
        uint32 _origin,
        bytes32 _sender,
        bytes calldata _data,
        address _token,
        uint256 _amount
    ) external override {
        emit ReceivedMessage(_origin, _sender, string(_data), _token, _amount);
        lastSender = _sender;
        lastData = _data;
        lastToken = _token;
        lastAmount = _amount;
    }

    function fooBar(uint256 amount, string calldata message) external {
        emit ReceivedCall(msg.sender, amount, message);
        lastCaller = msg.sender;
        lastCallMessage = message;
    }
}


// File @openzeppelin/contracts/proxy/Proxy.sol@v4.8.0


// OpenZeppelin Contracts (last updated v4.6.0) (proxy/Proxy.sol)

pragma solidity ^0.8.0;

/**
 * @dev This abstract contract provides a fallback function that delegates all calls to another contract using the EVM
 * instruction `delegatecall`. We refer to the second contract as the _implementation_ behind the proxy, and it has to
 * be specified by overriding the virtual {_implementation} function.
 *
 * Additionally, delegation to the implementation can be triggered manually through the {_fallback} function, or to a
 * different contract through the {_delegate} function.
 *
 * The success and return data of the delegated call will be returned back to the caller of the proxy.
 */
abstract contract Proxy {
    /**
     * @dev Delegates the current call to `implementation`.
     *
     * This function does not return to its internal call site, it will return directly to the external caller.
     */
    function _delegate(address implementation) internal virtual {
        assembly {
            // Copy msg.data. We take full control of memory in this inline assembly
            // block because it will not return to Solidity code. We overwrite the
            // Solidity scratch pad at memory position 0.
            calldatacopy(0, 0, calldatasize())

            // Call the implementation.
            // out and outsize are 0 because we don't know the size yet.
            let result := delegatecall(gas(), implementation, 0, calldatasize(), 0, 0)

            // Copy the returned data.
            returndatacopy(0, 0, returndatasize())

            switch result
            // delegatecall returns 0 on error.
            case 0 {
                revert(0, returndatasize())
            }
            default {
                return(0, returndatasize())
            }
        }
    }

    /**
     * @dev This is a virtual function that should be overridden so it returns the address to which the fallback function
     * and {_fallback} should delegate.
     */
    function _implementation() internal view virtual returns (address);

    /**
     * @dev Delegates the current call to the address returned by `_implementation()`.
     *
     * This function does not return to its internal call site, it will return directly to the external caller.
     */
    function _fallback() internal virtual {
        _beforeFallback();
        _delegate(_implementation());
    }

    /**
     * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if no other
     * function in the contract matches the call data.
     */
    fallback() external payable virtual {
        _fallback();
    }

    /**
     * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if call data
     * is empty.
     */
    receive() external payable virtual {
        _fallback();
    }

    /**
     * @dev Hook that is called before falling back to the implementation. Can happen as part of a manual `_fallback`
     * call, or as part of the Solidity `fallback` or `receive` functions.
     *
     * If overridden should call `super._beforeFallback()`.
     */
    function _beforeFallback() internal virtual {}
}


// File @openzeppelin/contracts/proxy/beacon/IBeacon.sol@v4.8.0


// OpenZeppelin Contracts v4.4.1 (proxy/beacon/IBeacon.sol)

pragma solidity ^0.8.0;

/**
 * @dev This is the interface that {BeaconProxy} expects of its beacon.
 */
interface IBeacon {
    /**
     * @dev Must return an address that can be used as a delegate call target.
     *
     * {BeaconProxy} will check that this address is a contract.
     */
    function implementation() external view returns (address);
}


// File @openzeppelin/contracts/interfaces/draft-IERC1822.sol@v4.8.0


// OpenZeppelin Contracts (last updated v4.5.0) (interfaces/draft-IERC1822.sol)

pragma solidity ^0.8.0;

/**
 * @dev ERC1822: Universal Upgradeable Proxy Standard (UUPS) documents a method for upgradeability through a simplified
 * proxy whose upgrades are fully controlled by the current implementation.
 */
interface IERC1822Proxiable {
    /**
     * @dev Returns the storage slot that the proxiable contract assumes is being used to store the implementation
     * address.
     *
     * IMPORTANT: A proxy pointing at a proxiable contract should not be considered proxiable itself, because this risks
     * bricking a proxy that upgrades to it, by delegating to itself until out of gas. Thus it is critical that this
     * function revert if invoked through a proxy.
     */
    function proxiableUUID() external view returns (bytes32);
}


// File @openzeppelin/contracts/utils/StorageSlot.sol@v4.8.0


// OpenZeppelin Contracts (last updated v4.7.0) (utils/StorageSlot.sol)

pragma solidity ^0.8.0;

/**
 * @dev Library for reading and writing primitive types to specific storage slots.
 *
 * Storage slots are often used to avoid storage conflict when dealing with upgradeable contracts.
 * This library helps with reading and writing to such slots without the need for inline assembly.
 *
 * The functions in this library return Slot structs that contain a `value` member that can be used to read or write.
 *
 * Example usage to set ERC1967 implementation slot:
 * ```
 * contract ERC1967 {
 *     bytes32 internal constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
 *
 *     function _getImplementation() internal view returns (address) {
 *         return StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value;
 *     }
 *
 *     function _setImplementation(address newImplementation) internal {
 *         require(Address.isContract(newImplementation), "ERC1967: new implementation is not a contract");
 *         StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
 *     }
 * }
 * ```
 *
 * _Available since v4.1 for `address`, `bool`, `bytes32`, and `uint256`._
 */
library StorageSlot {
    struct AddressSlot {
        address value;
    }

    struct BooleanSlot {
        bool value;
    }

    struct Bytes32Slot {
        bytes32 value;
    }

    struct Uint256Slot {
        uint256 value;
    }

    /**
     * @dev Returns an `AddressSlot` with member `value` located at `slot`.
     */
    function getAddressSlot(bytes32 slot) internal pure returns (AddressSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }

    /**
     * @dev Returns an `BooleanSlot` with member `value` located at `slot`.
     */
    function getBooleanSlot(bytes32 slot) internal pure returns (BooleanSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }

    /**
     * @dev Returns an `Bytes32Slot` with member `value` located at `slot`.
     */
    function getBytes32Slot(bytes32 slot) internal pure returns (Bytes32Slot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }

    /**
     * @dev Returns an `Uint256Slot` with member `value` located at `slot`.
     */
    function getUint256Slot(bytes32 slot) internal pure returns (Uint256Slot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }
}


// File @openzeppelin/contracts/proxy/ERC1967/ERC1967Upgrade.sol@v4.8.0


// OpenZeppelin Contracts (last updated v4.5.0) (proxy/ERC1967/ERC1967Upgrade.sol)

pragma solidity ^0.8.2;




/**
 * @dev This abstract contract provides getters and event emitting update functions for
 * https://eips.ethereum.org/EIPS/eip-1967[EIP1967] slots.
 *
 * _Available since v4.1._
 *
 * @custom:oz-upgrades-unsafe-allow delegatecall
 */
abstract contract ERC1967Upgrade {
    // This is the keccak-256 hash of "eip1967.proxy.rollback" subtracted by 1
    bytes32 private constant _ROLLBACK_SLOT = 0x4910fdfa16fed3260ed0e7147f7cc6da11a60208b5b9406d12a635614ffd9143;

    /**
     * @dev Storage slot with the address of the current implementation.
     * This is the keccak-256 hash of "eip1967.proxy.implementation" subtracted by 1, and is
     * validated in the constructor.
     */
    bytes32 internal constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;

    /**
     * @dev Emitted when the implementation is upgraded.
     */
    event Upgraded(address indexed implementation);

    /**
     * @dev Returns the current implementation address.
     */
    function _getImplementation() internal view returns (address) {
        return StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value;
    }

    /**
     * @dev Stores a new address in the EIP1967 implementation slot.
     */
    function _setImplementation(address newImplementation) private {
        require(Address.isContract(newImplementation), "ERC1967: new implementation is not a contract");
        StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
    }

    /**
     * @dev Perform implementation upgrade
     *
     * Emits an {Upgraded} event.
     */
    function _upgradeTo(address newImplementation) internal {
        _setImplementation(newImplementation);
        emit Upgraded(newImplementation);
    }

    /**
     * @dev Perform implementation upgrade with additional setup call.
     *
     * Emits an {Upgraded} event.
     */
    function _upgradeToAndCall(
        address newImplementation,
        bytes memory data,
        bool forceCall
    ) internal {
        _upgradeTo(newImplementation);
        if (data.length > 0 || forceCall) {
            Address.functionDelegateCall(newImplementation, data);
        }
    }

    /**
     * @dev Perform implementation upgrade with security checks for UUPS proxies, and additional setup call.
     *
     * Emits an {Upgraded} event.
     */
    function _upgradeToAndCallUUPS(
        address newImplementation,
        bytes memory data,
        bool forceCall
    ) internal {
        // Upgrades from old implementations will perform a rollback test. This test requires the new
        // implementation to upgrade back to the old, non-ERC1822 compliant, implementation. Removing
        // this special case will break upgrade paths from old UUPS implementation to new ones.
        if (StorageSlot.getBooleanSlot(_ROLLBACK_SLOT).value) {
            _setImplementation(newImplementation);
        } else {
            try IERC1822Proxiable(newImplementation).proxiableUUID() returns (bytes32 slot) {
                require(slot == _IMPLEMENTATION_SLOT, "ERC1967Upgrade: unsupported proxiableUUID");
            } catch {
                revert("ERC1967Upgrade: new implementation is not UUPS");
            }
            _upgradeToAndCall(newImplementation, data, forceCall);
        }
    }

    /**
     * @dev Storage slot with the admin of the contract.
     * This is the keccak-256 hash of "eip1967.proxy.admin" subtracted by 1, and is
     * validated in the constructor.
     */
    bytes32 internal constant _ADMIN_SLOT = 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;

    /**
     * @dev Emitted when the admin account has changed.
     */
    event AdminChanged(address previousAdmin, address newAdmin);

    /**
     * @dev Returns the current admin.
     */
    function _getAdmin() internal view returns (address) {
        return StorageSlot.getAddressSlot(_ADMIN_SLOT).value;
    }

    /**
     * @dev Stores a new address in the EIP1967 admin slot.
     */
    function _setAdmin(address newAdmin) private {
        require(newAdmin != address(0), "ERC1967: new admin is the zero address");
        StorageSlot.getAddressSlot(_ADMIN_SLOT).value = newAdmin;
    }

    /**
     * @dev Changes the admin of the proxy.
     *
     * Emits an {AdminChanged} event.
     */
    function _changeAdmin(address newAdmin) internal {
        emit AdminChanged(_getAdmin(), newAdmin);
        _setAdmin(newAdmin);
    }

    /**
     * @dev The storage slot of the UpgradeableBeacon contract which defines the implementation for this proxy.
     * This is bytes32(uint256(keccak256('eip1967.proxy.beacon')) - 1)) and is validated in the constructor.
     */
    bytes32 internal constant _BEACON_SLOT = 0xa3f0ad74e5423aebfd80d3ef4346578335a9a72aeaee59ff6cb3582b35133d50;

    /**
     * @dev Emitted when the beacon is upgraded.
     */
    event BeaconUpgraded(address indexed beacon);

    /**
     * @dev Returns the current beacon.
     */
    function _getBeacon() internal view returns (address) {
        return StorageSlot.getAddressSlot(_BEACON_SLOT).value;
    }

    /**
     * @dev Stores a new beacon in the EIP1967 beacon slot.
     */
    function _setBeacon(address newBeacon) private {
        require(Address.isContract(newBeacon), "ERC1967: new beacon is not a contract");
        require(
            Address.isContract(IBeacon(newBeacon).implementation()),
            "ERC1967: beacon implementation is not a contract"
        );
        StorageSlot.getAddressSlot(_BEACON_SLOT).value = newBeacon;
    }

    /**
     * @dev Perform beacon upgrade with additional setup call. Note: This upgrades the address of the beacon, it does
     * not upgrade the implementation contained in the beacon (see {UpgradeableBeacon-_setImplementation} for that).
     *
     * Emits a {BeaconUpgraded} event.
     */
    function _upgradeBeaconToAndCall(
        address newBeacon,
        bytes memory data,
        bool forceCall
    ) internal {
        _setBeacon(newBeacon);
        emit BeaconUpgraded(newBeacon);
        if (data.length > 0 || forceCall) {
            Address.functionDelegateCall(IBeacon(newBeacon).implementation(), data);
        }
    }
}


// File @openzeppelin/contracts/proxy/ERC1967/ERC1967Proxy.sol@v4.8.0


// OpenZeppelin Contracts (last updated v4.7.0) (proxy/ERC1967/ERC1967Proxy.sol)

pragma solidity ^0.8.0;


/**
 * @dev This contract implements an upgradeable proxy. It is upgradeable because calls are delegated to an
 * implementation address that can be changed. This address is stored in storage in the location specified by
 * https://eips.ethereum.org/EIPS/eip-1967[EIP1967], so that it doesn't conflict with the storage layout of the
 * implementation behind the proxy.
 */
contract ERC1967Proxy is Proxy, ERC1967Upgrade {
    /**
     * @dev Initializes the upgradeable proxy with an initial implementation specified by `_logic`.
     *
     * If `_data` is nonempty, it's used as data in a delegate call to `_logic`. This will typically be an encoded
     * function call, and allows initializing the storage of the proxy like a Solidity constructor.
     */
    constructor(address _logic, bytes memory _data) payable {
        _upgradeToAndCall(_logic, _data, false);
    }

    /**
     * @dev Returns the current implementation address.
     */
    function _implementation() internal view virtual override returns (address impl) {
        return ERC1967Upgrade._getImplementation();
    }
}


// File @openzeppelin/contracts/proxy/transparent/TransparentUpgradeableProxy.sol@v4.8.0


// OpenZeppelin Contracts (last updated v4.7.0) (proxy/transparent/TransparentUpgradeableProxy.sol)

pragma solidity ^0.8.0;

/**
 * @dev This contract implements a proxy that is upgradeable by an admin.
 *
 * To avoid https://medium.com/nomic-labs-blog/malicious-backdoors-in-ethereum-proxies-62629adf3357[proxy selector
 * clashing], which can potentially be used in an attack, this contract uses the
 * https://blog.openzeppelin.com/the-transparent-proxy-pattern/[transparent proxy pattern]. This pattern implies two
 * things that go hand in hand:
 *
 * 1. If any account other than the admin calls the proxy, the call will be forwarded to the implementation, even if
 * that call matches one of the admin functions exposed by the proxy itself.
 * 2. If the admin calls the proxy, it can access the admin functions, but its calls will never be forwarded to the
 * implementation. If the admin tries to call a function on the implementation it will fail with an error that says
 * "admin cannot fallback to proxy target".
 *
 * These properties mean that the admin account can only be used for admin actions like upgrading the proxy or changing
 * the admin, so it's best if it's a dedicated account that is not used for anything else. This will avoid headaches due
 * to sudden errors when trying to call a function from the proxy implementation.
 *
 * Our recommendation is for the dedicated account to be an instance of the {ProxyAdmin} contract. If set up this way,
 * you should think of the `ProxyAdmin` instance as the real administrative interface of your proxy.
 */
contract TransparentUpgradeableProxy is ERC1967Proxy {
    /**
     * @dev Initializes an upgradeable proxy managed by `_admin`, backed by the implementation at `_logic`, and
     * optionally initialized with `_data` as explained in {ERC1967Proxy-constructor}.
     */
    constructor(
        address _logic,
        address admin_,
        bytes memory _data
    ) payable ERC1967Proxy(_logic, _data) {
        _changeAdmin(admin_);
    }

    /**
     * @dev Modifier used internally that will delegate the call to the implementation unless the sender is the admin.
     */
    modifier ifAdmin() {
        if (msg.sender == _getAdmin()) {
            _;
        } else {
            _fallback();
        }
    }

    /**
     * @dev Returns the current admin.
     *
     * NOTE: Only the admin can call this function. See {ProxyAdmin-getProxyAdmin}.
     *
     * TIP: To get this value clients can read directly from the storage slot shown below (specified by EIP1967) using the
     * https://eth.wiki/json-rpc/API#eth_getstorageat[`eth_getStorageAt`] RPC call.
     * `0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103`
     */
    function admin() external ifAdmin returns (address admin_) {
        admin_ = _getAdmin();
    }

    /**
     * @dev Returns the current implementation.
     *
     * NOTE: Only the admin can call this function. See {ProxyAdmin-getProxyImplementation}.
     *
     * TIP: To get this value clients can read directly from the storage slot shown below (specified by EIP1967) using the
     * https://eth.wiki/json-rpc/API#eth_getstorageat[`eth_getStorageAt`] RPC call.
     * `0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc`
     */
    function implementation() external ifAdmin returns (address implementation_) {
        implementation_ = _implementation();
    }

    /**
     * @dev Changes the admin of the proxy.
     *
     * Emits an {AdminChanged} event.
     *
     * NOTE: Only the admin can call this function. See {ProxyAdmin-changeProxyAdmin}.
     */
    function changeAdmin(address newAdmin) external virtual ifAdmin {
        _changeAdmin(newAdmin);
    }

    /**
     * @dev Upgrade the implementation of the proxy.
     *
     * NOTE: Only the admin can call this function. See {ProxyAdmin-upgrade}.
     */
    function upgradeTo(address newImplementation) external ifAdmin {
        _upgradeToAndCall(newImplementation, bytes(""), false);
    }

    /**
     * @dev Upgrade the implementation of the proxy, and then call a function from the new implementation as specified
     * by `data`, which should be an encoded function call. This is useful to initialize new storage variables in the
     * proxied contract.
     *
     * NOTE: Only the admin can call this function. See {ProxyAdmin-upgradeAndCall}.
     */
    function upgradeToAndCall(address newImplementation, bytes calldata data) external payable ifAdmin {
        _upgradeToAndCall(newImplementation, data, true);
    }

    /**
     * @dev Returns the current admin.
     */
    function _admin() internal view virtual returns (address) {
        return _getAdmin();
    }

    /**
     * @dev Makes sure the admin cannot access the fallback function. See {Proxy-_beforeFallback}.
     */
    function _beforeFallback() internal virtual override {
        require(msg.sender != _getAdmin(), "TransparentUpgradeableProxy: admin cannot fallback to proxy target");
        super._beforeFallback();
    }
}


// File @openzeppelin/contracts/proxy/transparent/ProxyAdmin.sol@v4.8.0


// OpenZeppelin Contracts v4.4.1 (proxy/transparent/ProxyAdmin.sol)

pragma solidity ^0.8.0;


/**
 * @dev This is an auxiliary contract meant to be assigned as the admin of a {TransparentUpgradeableProxy}. For an
 * explanation of why you would want to use this see the documentation for {TransparentUpgradeableProxy}.
 */
contract ProxyAdmin is Ownable {
    /**
     * @dev Returns the current implementation of `proxy`.
     *
     * Requirements:
     *
     * - This contract must be the admin of `proxy`.
     */
    function getProxyImplementation(TransparentUpgradeableProxy proxy) public view virtual returns (address) {
        // We need to manually run the static call since the getter cannot be flagged as view
        // bytes4(keccak256("implementation()")) == 0x5c60da1b
        (bool success, bytes memory returndata) = address(proxy).staticcall(hex"5c60da1b");
        require(success);
        return abi.decode(returndata, (address));
    }

    /**
     * @dev Returns the current admin of `proxy`.
     *
     * Requirements:
     *
     * - This contract must be the admin of `proxy`.
     */
    function getProxyAdmin(TransparentUpgradeableProxy proxy) public view virtual returns (address) {
        // We need to manually run the static call since the getter cannot be flagged as view
        // bytes4(keccak256("admin()")) == 0xf851a440
        (bool success, bytes memory returndata) = address(proxy).staticcall(hex"f851a440");
        require(success);
        return abi.decode(returndata, (address));
    }

    /**
     * @dev Changes the admin of `proxy` to `newAdmin`.
     *
     * Requirements:
     *
     * - This contract must be the current admin of `proxy`.
     */
    function changeProxyAdmin(TransparentUpgradeableProxy proxy, address newAdmin) public virtual onlyOwner {
        proxy.changeAdmin(newAdmin);
    }

    /**
     * @dev Upgrades `proxy` to `implementation`. See {TransparentUpgradeableProxy-upgradeTo}.
     *
     * Requirements:
     *
     * - This contract must be the admin of `proxy`.
     */
    function upgrade(TransparentUpgradeableProxy proxy, address implementation) public virtual onlyOwner {
        proxy.upgradeTo(implementation);
    }

    /**
     * @dev Upgrades `proxy` to `implementation` and calls a function on the new implementation. See
     * {TransparentUpgradeableProxy-upgradeToAndCall}.
     *
     * Requirements:
     *
     * - This contract must be the admin of `proxy`.
     */
    function upgradeAndCall(
        TransparentUpgradeableProxy proxy,
        address implementation,
        bytes memory data
    ) public payable virtual onlyOwner {
        proxy.upgradeToAndCall{value: msg.value}(implementation, data);
    }
}


// File contracts/upgrade/ProxyAdmin.sol


// OpenZeppelin Contracts v4.4.1 (proxy/transparent/ProxyAdmin.sol)

pragma solidity ^0.8.0;


// File contracts/upgrade/TransparentUpgradeableProxy.sol


// OpenZeppelin Contracts (last updated v4.7.0) (proxy/transparent/TransparentUpgradeableProxy.sol)

pragma solidity ^0.8.0;


// File contracts/Create2Factory.sol


// Copied from https://github.com/axelarnetwork/axelar-utils-solidity/commits/main/contracts/ConstAddressDeployer.sol

pragma solidity ^0.8.0;

contract Create2Factory {
    error EmptyBytecode();
    error FailedDeploy();
    error FailedInit();

    event Deployed(
        bytes32 indexed bytecodeHash,
        bytes32 indexed salt,
        address indexed deployedAddress
    );

    /**
     * @dev Deploys a contract using `CREATE2`. The address where the contract
     * will be deployed can be known in advance via {deployedAddress}.
     *
     * The bytecode for a contract can be obtained from Solidity with
     * `type(contractName).creationCode`.
     *
     * Requirements:
     *
     * - `bytecode` must not be empty.
     * - `salt` must have not been used for `bytecode` already by the same `msg.sender`.
     */
    function deploy(bytes memory bytecode, bytes32 salt)
        external
        returns (address deployedAddress_)
    {
        deployedAddress_ = _deploy(
            bytecode,
            keccak256(abi.encode(msg.sender, salt))
        );
    }

    /**
     * @dev Deploys a contract using `CREATE2` and initialize it. The address where the contract
     * will be deployed can be known in advance via {deployedAddress}.
     *
     * The bytecode for a contract can be obtained from Solidity with
     * `type(contractName).creationCode`.
     *
     * Requirements:
     *
     * - `bytecode` must not be empty.
     * - `salt` must have not been used for `bytecode` already by the same `msg.sender`.
     * - `init` is used to initialize the deployed contract
     *    as an option to not have the constructor args affect the address derived by `CREATE2`.
     */
    function deployAndInit(
        bytes memory bytecode,
        bytes32 salt,
        bytes calldata init
    ) external returns (address deployedAddress_) {
        deployedAddress_ = _deploy(
            bytecode,
            keccak256(abi.encode(msg.sender, salt))
        );

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, ) = deployedAddress_.call(init);
        if (!success) revert FailedInit();
    }

    /**
     * @dev Returns the address where a contract will be stored if deployed via {deploy} or {deployAndInit} by `sender`.
     * Any change in the `bytecode`, `sender`, or `salt` will result in a new destination address.
     */
    function deployedAddress(
        bytes calldata bytecode,
        address sender,
        bytes32 salt
    ) external view returns (address deployedAddress_) {
        bytes32 newSalt = keccak256(abi.encode(sender, salt));
        deployedAddress_ = address(
            uint160(
                uint256(
                    keccak256(
                        abi.encodePacked(
                            hex"ff",
                            address(this),
                            newSalt,
                            keccak256(bytecode) // init code hash
                        )
                    )
                )
            )
        );
    }

    function _deploy(bytes memory bytecode, bytes32 salt)
        internal
        returns (address deployedAddress_)
    {
        if (bytecode.length == 0) revert EmptyBytecode();

        // solhint-disable-next-line no-inline-assembly
        assembly {
            deployedAddress_ := create2(
                0,
                add(bytecode, 32),
                mload(bytecode),
                salt
            )
        }

        if (deployedAddress_ == address(0)) revert FailedDeploy();

        emit Deployed(keccak256(bytecode), salt, deployedAddress_);
    }
}


// File contracts/test/bad-recipient/BadRecipient2.sol


pragma solidity >=0.8.0;

contract BadRecipient2 {
    function handle(uint32, bytes32) external pure {} // solhint-disable-line no-empty-blocks
}