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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (proxy/utils/Initializable.sol)

pragma solidity ^0.8.2;

import "../../utils/AddressUpgradeable.sol";

/**
 * @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/AddressUpgradeable.sol



// SPDX-License-Identifier: MIT
// 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/security/Pausable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (security/Pausable.sol)

pragma solidity ^0.8.0;

import "../utils/Context.sol";

/**
 * @dev Contract module which allows children to implement an emergency stop
 * mechanism that can be triggered by an authorized account.
 *
 * This module is used through inheritance. It will make available the
 * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
 * the functions of your contract. Note that they will not be pausable by
 * simply including this module, only once the modifiers are put in place.
 */
abstract contract Pausable is Context {
    /**
     * @dev Emitted when the pause is triggered by `account`.
     */
    event Paused(address account);

    /**
     * @dev Emitted when the pause is lifted by `account`.
     */
    event Unpaused(address account);

    bool private _paused;

    /**
     * @dev Initializes the contract in unpaused state.
     */
    constructor() {
        _paused = false;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is not paused.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    modifier whenNotPaused() {
        _requireNotPaused();
        _;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    modifier whenPaused() {
        _requirePaused();
        _;
    }

    /**
     * @dev Returns true if the contract is paused, and false otherwise.
     */
    function paused() public view virtual returns (bool) {
        return _paused;
    }

    /**
     * @dev Throws if the contract is paused.
     */
    function _requireNotPaused() internal view virtual {
        require(!paused(), "Pausable: paused");
    }

    /**
     * @dev Throws if the contract is not paused.
     */
    function _requirePaused() internal view virtual {
        require(paused(), "Pausable: not paused");
    }

    /**
     * @dev Triggers stopped state.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    function _pause() internal virtual whenNotPaused {
        _paused = true;
        emit Paused(_msgSender());
    }

    /**
     * @dev Returns to normal state.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    function _unpause() internal virtual whenPaused {
        _paused = false;
        emit Unpaused(_msgSender());
    }
}

// File: @openzeppelin/contracts/utils/Context.sol



// SPDX-License-Identifier: MIT
// 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: contracts/messaging/MerkleTreeManager.sol



// SPDX-License-Identifier: MIT OR Apache-2.0
pragma solidity 0.8.17;

import {ProposedOwnableUpgradeable} from "../shared/ProposedOwnableUpgradeable.sol";
import {MerkleLib} from "./libraries/MerkleLib.sol";

/**
 * @title MerkleTreeManager
 * @notice Contains a Merkle tree instance and exposes read/write functions for the tree.
 * @dev On the hub domain there are two MerkleTreeManager contracts, one for the hub and one for the MainnetSpokeConnector.
 */
contract MerkleTreeManager is ProposedOwnableUpgradeable {
  // ========== Custom Errors ===========

  error MerkleTreeManager__setArborist_zeroAddress();
  error MerkleTreeManager__setArborist_alreadyArborist();

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

  event ArboristUpdated(address previous, address updated);

  // ============ Libraries ============

  using MerkleLib for MerkleLib.Tree;

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

  /**
   * @notice Core data structure with which this contract is tasked with keeping custody.
   * Writable only by the designated arborist.
   */
  MerkleLib.Tree public tree;

  /**
   * @notice The arborist contract that has permission to write to this tree.
   * @dev This could be the root manager contract or a spoke connector contract, for example.
   */
  address public arborist;

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

  modifier onlyArborist() {
    require(arborist == msg.sender, "!arborist");
    _;
  }

  // ============ Getters ============

  /**
   * @notice Returns the current branch.
   */
  function branch() public view returns (bytes32[32] memory) {
    return tree.branch;
  }

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

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

  /**
   * @notice Convenience getter: returns the root and count.
   */
  function rootAndCount() public view returns (bytes32, uint256) {
    return (tree.root(), tree.count);
  }

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

  function initialize(address _arborist) public initializer {
    __MerkleTreeManager_init(_arborist);
    __ProposedOwnable_init();
  }

  /**
   * @dev Initializes MerkleTreeManager instance. Sets the msg.sender as the initial permissioned
   */
  function __MerkleTreeManager_init(address _arborist) internal onlyInitializing {
    __MerkleTreeManager_init_unchained(_arborist);
  }

  function __MerkleTreeManager_init_unchained(address _arborist) internal onlyInitializing {
    arborist = _arborist;
  }

  // ============ Admin Functions ==============

  /**
   * @notice Method for the current arborist to assign write permissions to a new arborist.
   * @param newArborist The new address to set as the current arborist.
   */
  function setArborist(address newArborist) external onlyOwner {
    if (newArborist == address(0)) revert MerkleTreeManager__setArborist_zeroAddress();
    address current = arborist;
    if (current == newArborist) revert MerkleTreeManager__setArborist_alreadyArborist();

    // Emit updated event
    emit ArboristUpdated(current, newArborist);

    arborist = newArborist;
  }

  /**
   * @notice Remove ability to renounce ownership
   * @dev Renounce ownership should be impossible as long as there is a possibility the
   * arborist may change.
   */
  function renounceOwnership() public virtual override onlyOwner {}

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

  /**
   * @notice Inserts the given leaves into the tree.
   * @param leaves The leaves to be inserted into the tree.
   * @return _root Current root for convenience.
   * @return _count Current node count (i.e. number of indices) AFTER the insertion of the new leaf,
   * provided for convenience.
   */
  function insert(bytes32[] memory leaves) public onlyArborist returns (bytes32 _root, uint256 _count) {
    // For > 1 leaf, considerably more efficient to put this tree into memory, conduct operations,
    // then re-assign it to storage - *especially* if we have multiple leaves to insert.
    MerkleLib.Tree memory _tree = tree;

    uint256 leafCount = leaves.length;
    for (uint256 i; i < leafCount; ) {
      // Insert the new node (using in-memory method).
      _tree = _tree.insert(leaves[i]);
      unchecked {
        ++i;
      }
    }
    // Write the newly updated tree to storage.
    tree = _tree;

    // Get return details for convenience.
    _count = _tree.count;
    // NOTE: Root calculation method currently reads from storage only.
    _root = tree.root();
  }

  /**
   * @notice Inserts the given leaf into the tree.
   * @param leaf The leaf to be inserted into the tree.
   * @return _root Current root for convenience.
   * @return _count Current node count (i.e. number of indices) AFTER the insertion of the new leaf,
   * provided for convenience.
   */
  function insert(bytes32 leaf) public onlyArborist returns (bytes32 _root, uint256 _count) {
    // Insert the new node.
    tree = tree.insert(leaf);
    _count = tree.count;
    _root = tree.root();
  }

  // ============ Upgrade Gap ============
  uint256[48] private __GAP; // gap for upgrade safety
}

// File: contracts/messaging/RootManager.sol



// SPDX-License-Identifier: MIT OR Apache-2.0
pragma solidity 0.8.17;

import {ProposedOwnable} from "../shared/ProposedOwnable.sol";

import {IRootManager} from "./interfaces/IRootManager.sol";
import {IHubConnector} from "./interfaces/IHubConnector.sol";
import {QueueLib} from "./libraries/Queue.sol";
import {DomainIndexer} from "./libraries/DomainIndexer.sol";

import {MerkleTreeManager} from "./MerkleTreeManager.sol";
import {WatcherClient} from "./WatcherClient.sol";

/**
 * @notice This contract exists at cluster hubs, and aggregates all transfer roots from messaging
 * spokes into a single merkle tree. Regularly broadcasts the root of the aggregator tree back out
 * to all the messaging spokes.
 */
contract RootManager is ProposedOwnable, IRootManager, WatcherClient, DomainIndexer {
  // ============ Libraries ============

  using QueueLib for QueueLib.Queue;

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

  event DelayBlocksUpdated(uint256 previous, uint256 updated);

  event RootReceived(uint32 domain, bytes32 receivedRoot, uint256 queueIndex);

  event RootsAggregated(bytes32 aggregateRoot, uint256 count, bytes32[] aggregatedMessageRoots);

  event RootPropagated(bytes32 aggregateRoot, uint256 count, bytes32 domainsHash);

  event RootDiscarded(bytes32 fraudulentRoot);

  event ConnectorAdded(uint32 domain, address connector, uint32[] domains, address[] connectors);

  event ConnectorRemoved(uint32 domain, address connector, uint32[] domains, address[] connectors, address caller);

  event PropagateFailed(uint32 domain, address connector);

  // ============ Properties ============

  /**
   * @notice Maximum number of values to dequeue from the queue in one sitting (one call of `propagate`
   * or `dequeue`). Used to cap gas requirements.
   */
  uint128 public constant DEQUEUE_MAX = 100;

  /**
   * @notice Number of blocks to delay the processing of a message to allow for watchers to verify
   * the validity and pause if necessary.
   */
  uint256 public delayBlocks;

  /**
   * @notice Queue used for management of verification for inbound roots from spoke chains. Once
   * the verification period elapses, the inbound messages can be aggregated into the merkle tree
   * for propagation to spoke chains.
   * @dev Watchers should be able to watch this queue for fraudulent messages and pause this contract
   * if fraud is detected.
   */
  QueueLib.Queue public pendingInboundRoots;

  /**
   * @notice The last aggregate root we propagated to spoke chains. Used to prevent sending redundant
   * aggregate roots in `propagate`.
   */
  bytes32 public lastPropagatedRoot;

  /**
   * @notice MerkleTreeManager contract instance. Will hold the active tree of aggregated inbound roots.
   * The root of this tree will be distributed crosschain to all spoke domains.
   */
  MerkleTreeManager public immutable MERKLE;

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

  modifier onlyConnector(uint32 _domain) {
    require(getConnectorForDomain(_domain) == msg.sender, "!connector");
    _;
  }

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

  /**
   * @notice Creates a new RootManager instance.
   * @param _delayBlocks The delay for the validation period for incoming messages in blocks.
   * @param _merkle The address of the MerkleTreeManager on this domain.
   * @param _watcherManager The address of the WatcherManager on this domain.
   */
  constructor(
    uint256 _delayBlocks,
    address _merkle,
    address _watcherManager
  ) ProposedOwnable() WatcherClient(_watcherManager) {
    _setOwner(msg.sender);

    require(_merkle != address(0), "!zero merkle");
    MERKLE = MerkleTreeManager(_merkle);

    delayBlocks = _delayBlocks;

    // Initialize pending inbound root queue.
    pendingInboundRoots.initialize();
  }

  // ================ Getters ================

  function getPendingInboundRootsCount() public view returns (uint256) {
    return pendingInboundRoots.length();
  }

  // ============ Admin Functions ============

  /**
   * @notice Set the `delayBlocks`, the period in blocks over which an incoming message
   * is verified.
   */
  function setDelayBlocks(uint256 _delayBlocks) public onlyOwner {
    require(_delayBlocks != delayBlocks, "!delayBlocks");
    emit DelayBlocksUpdated(_delayBlocks, delayBlocks);
    delayBlocks = _delayBlocks;
  }

  /**
   * @notice Add a new supported domain and corresponding hub connector to the system. This new domain
   * will receive the propagated aggregate root.
   * @dev Only owner can add a new connector. Address should be the connector on L1.
   * @dev Cannot add address(0) to avoid duplicated domain in array and reduce gas fee while propagating.
   *
   * @param _domain The target spoke domain of the given connector.
   * @param _connector Address of the hub connector.
   */
  function addConnector(uint32 _domain, address _connector) external onlyOwner {
    addDomain(_domain, _connector);
    emit ConnectorAdded(_domain, _connector, domains, connectors);
  }

  /**
   * @notice Remove support for a connector and respective domain. That connector/domain will no longer
   * receive updates for the latest aggregate root.
   * @dev Only watcher can remove a connector.
   * TODO: Could add a metatx-able `removeConnectorWithSig` if we want to use relayers?
   *
   * @param _domain The spoke domain of the target connector we want to remove.
   */
  function removeConnector(uint32 _domain) public onlyWatcher {
    address _connector = removeDomain(_domain);
    emit ConnectorRemoved(_domain, _connector, domains, connectors, msg.sender);
  }

  /**
   * @notice Removes (effectively blocklists) a given (fraudulent) root from the queue of pending
   * inbound roots.
   * @dev The given root does NOT have to currently be in the queue. It isn't removed from the queue
   * directly, but instead is filtered out when dequeuing is done for the sake of aggregation.
   * @dev Can only be called by the owner when the protocol is paused.
   *
   * @param _root The root to be discarded.
   */
  function discardRoot(bytes32 _root) public onlyOwner whenPaused {
    pendingInboundRoots.remove(_root);
    emit RootDiscarded(_root);
  }

  /**
   * @notice Remove ability to renounce ownership
   * @dev Renounce ownership should be impossible as long as watchers can freely remove connectors
   * and only the owner can add them back
   */
  function renounceOwnership() public virtual override(ProposedOwnable, WatcherClient) onlyOwner {}

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

  /**
   * @notice This is called by relayers to take the current aggregate tree root and propagate it to all
   * spoke domains (via their respective hub connectors).
   * @dev Should be called by relayers at a regular interval.
   *
   * @param _connectors Array of connectors: should match exactly the array of `connectors` in storage;
   * used here to reduce gas costs, and keep them static regardless of number of supported domains.
   * @param _fees Array of fees in native token for an AMB if required
   * @param _encodedData Array of encodedData: extra params for each AMB if required
   */
  function propagate(
    address[] calldata _connectors,
    uint256[] calldata _fees,
    bytes[] memory _encodedData
  ) external payable whenNotPaused {
    validateConnectors(_connectors);

    uint256 _numDomains = _connectors.length;
    // Sanity check: fees and encodedData lengths matches connectors length.
    require(_fees.length == _numDomains && _encodedData.length == _numDomains, "invalid lengths");

    // Dequeue verified roots from the queue and insert into the tree.
    (bytes32 _aggregateRoot, uint256 _count) = dequeue();

    // Sanity check: make sure we are not propagating a redundant aggregate root.
    require(_aggregateRoot != lastPropagatedRoot, "redundant root");
    lastPropagatedRoot = _aggregateRoot;

    uint256 sum = msg.value;
    for (uint32 i; i < _numDomains; ) {
      // Try to send the message with appropriate encoded data and fees
      // Continue on revert, but emit an event
      try
        IHubConnector(_connectors[i]).sendMessage{value: _fees[i]}(abi.encodePacked(_aggregateRoot), _encodedData[i])
      {
        // NOTE: This will ensure there is sufficient msg.value for all fees before calling `sendMessage`
        // This will revert as soon as there are insufficient fees for call i, even if call n > i has
        // sufficient budget, this function will revert
        sum -= _fees[i];
      } catch {
        emit PropagateFailed(domains[i], _connectors[i]);
      }

      unchecked {
        ++i;
      }
    }

    emit RootPropagated(_aggregateRoot, _count, domainsHash);
  }

  /**
   * @notice Accept an inbound root coming from a given domain's hub connector, enqueuing this incoming
   * root into the current queue as it awaits the verification period.
   * @dev The aggregate tree's root, which will include this inbound root, will be propagated to all spoke
   * domains (via `propagate`) on a regular basis assuming the verification period is surpassed without
   * dispute.
   *
   * @param _domain The source domain of the given root.
   * @param _inbound The inbound root coming from the given domain.
   */
  function aggregate(uint32 _domain, bytes32 _inbound) external whenNotPaused onlyConnector(_domain) {
    uint128 lastIndex = pendingInboundRoots.enqueue(_inbound);
    emit RootReceived(_domain, _inbound, lastIndex);
  }

  /**
   * @notice Dequeue verified inbound roots and insert them into the aggregator tree.
   * @dev Will dequeue a fixed maximum amount of roots to prevent out of gas errors. As such, this
   * method is public and separate from `propagate` so we can curtail an overloaded queue as needed.
   * @dev Reverts if no verified inbound roots are found.
   *
   * @return bytes32 The new aggregate root.
   * @return uint256 The updated count (number of leaves).
   */
  function dequeue() public whenNotPaused returns (bytes32, uint256) {
    // Get all of the verified roots from the queue.
    bytes32[] memory _verifiedInboundRoots = pendingInboundRoots.dequeueVerified(delayBlocks, DEQUEUE_MAX);

    // If there's nothing dequeued, just return the root and count.
    if (_verifiedInboundRoots.length == 0) {
      return MERKLE.rootAndCount();
    }

    // Insert the leaves into the aggregator tree (method will also calculate and return the current
    // aggregate root and count).
    (bytes32 _aggregateRoot, uint256 _count) = MERKLE.insert(_verifiedInboundRoots);

    emit RootsAggregated(_aggregateRoot, _count, _verifiedInboundRoots);

    return (_aggregateRoot, _count);
  }
}

// File: contracts/messaging/WatcherClient.sol



// SPDX-License-Identifier: MIT OR Apache-2.0
pragma solidity 0.8.17;

import {Pausable} from "@openzeppelin/contracts/security/Pausable.sol";

import {ProposedOwnable} from "../shared/ProposedOwnable.sol";
import {WatcherManager} from "./WatcherManager.sol";

/**
 * @notice This contract abstracts the functionality of the watcher manager.
 * Contracts can inherit this contract to be able to use the watcher manager's shared watcher set.
 */

contract WatcherClient is ProposedOwnable, Pausable {
  // ============ Events ============
  /**
   * @notice Emitted when the manager address changes
   * @param watcherManager The updated manager
   */
  event WatcherManagerChanged(address watcherManager);

  // ============ Properties ============
  /**
   * @notice The `WatcherManager` contract governs the watcher allowlist.
   * @dev Multiple clients can share a watcher set using the same manager
   */
  WatcherManager public watcherManager;

  // ============ Constructor ============
  constructor(address _watcherManager) ProposedOwnable() {
    watcherManager = WatcherManager(_watcherManager);
  }

  // ============ Modifiers ============
  /**
   * @notice Enforces the sender is the watcher
   */
  modifier onlyWatcher() {
    require(watcherManager.isWatcher(msg.sender), "!watcher");
    _;
  }

  // ============ Admin fns ============
  /**
   * @notice Owner can enroll a watcher (abilities are defined by inheriting contracts)
   */
  function setWatcherManager(address _watcherManager) external onlyOwner {
    require(_watcherManager != address(watcherManager), "already watcher manager");
    watcherManager = WatcherManager(_watcherManager);
    emit WatcherManagerChanged(_watcherManager);
  }

  /**
   * @notice Owner can unpause contracts if fraud is detected by watchers
   */
  function unpause() external onlyOwner whenPaused {
    _unpause();
  }

  /**
   * @notice Remove ability to renounce ownership
   * @dev Renounce ownership should be impossible as long as only the owner
   * is able to unpause the contracts. You can still propose `address(0)`,
   * but it will never be accepted.
   */
  function renounceOwnership() public virtual override onlyOwner {}

  // ============ Watcher fns ============

  /**
   * @notice Watchers can pause contracts if fraud is detected
   */
  function pause() external onlyWatcher whenNotPaused {
    _pause();
  }
}

// File: contracts/messaging/WatcherManager.sol



// SPDX-License-Identifier: MIT OR Apache-2.0
pragma solidity 0.8.17;

import {ProposedOwnable} from "../shared/ProposedOwnable.sol";

/**
 * @notice This contract manages a set of watchers. This is meant to be used as a shared resource that contracts can
 * inherit to make use of the same watcher set.
 */

contract WatcherManager is ProposedOwnable {
  // ============ Events ============
  event WatcherAdded(address watcher);

  event WatcherRemoved(address watcher);

  // ============ Properties ============
  mapping(address => bool) public isWatcher;

  // ============ Constructor ============
  constructor() ProposedOwnable() {
    _setOwner(msg.sender);
  }

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

  // ============ Admin fns ============
  /**
   * @dev Owner can enroll a watcher (abilities are defined by inheriting contracts)
   */
  function addWatcher(address _watcher) external onlyOwner {
    require(!isWatcher[_watcher], "already watcher");
    isWatcher[_watcher] = true;
    emit WatcherAdded(_watcher);
  }

  /**
   * @dev Owner can unenroll a watcher (abilities are defined by inheriting contracts)
   */
  function removeWatcher(address _watcher) external onlyOwner {
    require(isWatcher[_watcher], "!exist");
    delete isWatcher[_watcher];
    emit WatcherRemoved(_watcher);
  }

  /**
   * @notice Remove ability to renounce ownership
   * @dev Renounce ownership should be impossible as long as the watcher griefing
   * vector exists. You can still propose `address(0)`, but it will never be accepted.
   */
  function renounceOwnership() public virtual override onlyOwner {}
}

// File: contracts/messaging/interfaces/IConnector.sol



// SPDX-License-Identifier: MIT OR Apache-2.0
pragma solidity 0.8.17;

import {IProposedOwnable} from "../../shared/interfaces/IProposedOwnable.sol";

/**
 * @notice This interface is what the Connext contract will send and receive messages through.
 * The messaging layer should conform to this interface, and should be interchangeable (i.e.
 * could be Nomad or a generic AMB under the hood).
 *
 * @dev This uses the nomad format to ensure nomad can be added in as it comes back online.
 *
 * Flow from transfer from polygon to optimism:
 * 1. User calls `xcall` with destination specified
 * 2. This will swap in to the bridge assets
 * 3. The swapped assets will get burned
 * 4. The Connext contract will call `dispatch` on the messaging contract to add the transfer
 *    to the root
 * 5. [At some time interval] Relayers call `send` to send the current root from polygon to
 *    mainnet. This is done on all "spoke" domains.
 * 6. [At some time interval] Relayers call `propagate` [better name] on mainnet, this generates a new merkle
 *    root from all of the AMBs
 *    - This function must be able to read root data from all AMBs and aggregate them into a single merkle
 *      tree root
 *    - Will send the mixed root from all chains back through the respective AMBs to all other chains
 * 7. AMB will call `update` to update the latest root on the messaging contract on spoke domains
 * 8. [At any point] Relayers can call `proveAndProcess` to prove inclusion of dispatched message, and call
 *    process on the `Connext` contract
 * 9. Takes minted bridge tokens and credits the LP
 *
 * AMB requirements:
 * - Access `msg.sender` both from mainnet -> spoke and vice versa
 * - Ability to read *our root* from the AMB
 *
 * AMBs:
 * - PoS bridge from polygon
 * - arbitrum bridge
 * - optimism bridge
 * - gnosis chain
 * - bsc (use multichain for messaging)
 */
interface IConnector is IProposedOwnable {
  // ============ Events ============
  /**
   * @notice Emitted whenever a message is successfully sent over an AMB
   * @param data The contents of the message
   * @param encodedData Data used to send the message; specific to connector
   * @param caller Who called the function (sent the message)
   */
  event MessageSent(bytes data, bytes encodedData, address caller);

  /**
   * @notice Emitted whenever a message is successfully received over an AMB
   * @param data The contents of the message
   * @param caller Who called the function
   */
  event MessageProcessed(bytes data, address caller);

  // ============ Public fns ============

  function processMessage(bytes memory _data) external;

  function verifySender(address _expected) external returns (bool);
}

// File: contracts/messaging/interfaces/IHubConnector.sol



// SPDX-License-Identifier: MIT OR Apache-2.0
pragma solidity 0.8.17;

import {IConnector} from "./IConnector.sol";

interface IHubConnector is IConnector {
  function sendMessage(bytes memory _data, bytes memory _encodedData) external payable;
}

// File: contracts/messaging/interfaces/IRootManager.sol



// SPDX-License-Identifier: MIT OR Apache-2.0
pragma solidity 0.8.17;

interface IRootManager {
  /**
   * @notice This is called by relayers to generate + send the mixed root from mainnet via AMB to
   * spoke domains.
   * @dev This must read information for the root from the registered AMBs.
   */
  function propagate(
    address[] calldata _connectors,
    uint256[] calldata _fees,
    bytes[] memory _encodedData
  ) external payable;

  /**
   * @notice Called by the connectors for various domains on the hub to aggregate their latest
   * inbound root.
   * @dev This must read information for the root from the registered AMBs
   */
  function aggregate(uint32 _domain, bytes32 _outbound) external;
}

// File: contracts/messaging/libraries/DomainIndexer.sol



// SPDX-License-Identifier: MIT OR Apache-2.0
pragma solidity 0.8.17;

/**
 * @notice This abstract contract was written to ensure domain and connector mutex is scalable for the
 * purposes of messaging layer operations. In particular, it aims to reduce gas costs to be relatively
 * static regardless of the number of domains kept in storage by enabling callers of `RootManager.propagate`
 * to supply the `domains` and `connectors` arrays as params, and check the hashes of those params against
 * those we keep in storage.
 */
abstract contract DomainIndexer {
  // ============ Events ============

  event DomainAdded(uint32 domain, address connector);
  event DomainRemoved(uint32 domain);

  // ============ Properties ============

  /**
   * @notice The absolute maximum number of domains that we should support. Domain and connector arrays
   * are naturally unbounded, but the gas cost of reading these arrays in `updateHashes()` is bounded by
   * the block's gas limit.
   *
   * If we want to set a hard ceiling for gas costs for the `updateHashes()` method at approx. 500K gas,
   * with an average SLOAD cost of 900 gas per domain (1 uint32, 1 address):
   *       500K / 900 = ~555 domains
   *
   * Realistically, the cap on the number of domains will likely exist in other places, but we cap it
   * here as a last resort.
   */
  uint256 public constant MAX_DOMAINS = 500;

  /**
   * @notice Domains array tracks currently subscribed domains to this hub aggregator.
   * We should distribute the aggregate root to all of these domains in the `propagate` method.
   * @dev Whenever this domains array is updated, the connectors array should also be updated.
   */
  uint32[] public domains;

  /**
   * @notice A "quick reference" hash used in the `propagate` method below to validate that the provided
   * array of domains matches the one we have in storage.
   * @dev This hash should be re-calculated whenever the domains array is updated.
   */
  bytes32 public domainsHash;

  /**
   * @notice Tracks the addresses of the hub connector contracts corresponding to subscribed spoke domains.
   * The index of any given connector in this array should match the index of that connector's target spoke
   * domain in the `domains` array above.
   * @dev This should be updated whenever the domains array is updated.
   */
  address[] public connectors;

  /**
   * @notice A "quick reference" hash used in the `propagate` method below to validate that the provided
   * array of connectors matches the one we have in storage.
   * @dev This hash should be re-calculated whenever the connectors array is updated.
   */
  bytes32 public connectorsHash;

  /**
   * @notice Shortcut to reverse lookup the index by domain. We index starting at one so the zero value can
   * be considered invalid (see fn: `isDomainSupported`).
   * @dev This should be updated whenever the domains array is updated.
   */
  mapping(uint32 => uint256) private domainToIndexPlusOne;

  // ============ Getters ============

  /**
   * @notice Convenience shortcut for supported domains. Used to sanity check adding new domains.
   * @param _domain Domain to check.
   */
  function isDomainSupported(uint32 _domain) public view returns (bool) {
    return domainToIndexPlusOne[_domain] != 0;
  }

  /**
   * @notice Gets the index of a given domain in the domains and connectors arrays.
   * @dev Reverts if domain is not supported.
   * @param _domain The domain for which to get the index value.
   */
  function getDomainIndex(uint32 _domain) public view returns (uint256) {
    uint256 index = domainToIndexPlusOne[_domain];
    require(index != 0, "!supported");
    return index - 1;
  }

  /**
   * @notice Gets the corresponding hub connector address for a given spoke domain.
   * @dev Inefficient, should only be used by caller if they have no index reference.
   * @param _domain The domain for which to get the hub connector address.
   */
  function getConnectorForDomain(uint32 _domain) public view returns (address) {
    return connectors[getDomainIndex(_domain)];
  }

  /**
   * @notice Validate given domains and connectors arrays are correct (i.e. they mirror what is
   * currently saved in storage).
   * @dev Reverts if domains or connectors do not match, including ordering.
   * @param _domains The given domains array to check.
   * @param _connectors The given connectors array to check.
   */
  function validateDomains(uint32[] calldata _domains, address[] calldata _connectors) public view {
    // Sanity check: arguments are same length.
    require(_domains.length == _connectors.length, "!matching length");
    // Validate that given domains match the current array in storage.
    require(keccak256(abi.encode(_domains)) == domainsHash, "!domains");
    // Validate that given connectors match the current array in storage.
    require(keccak256(abi.encode(_connectors)) == connectorsHash, "!connectors");
  }

  /**
   * @notice Validate given connectors array is correct (i.e. it mirrors what is
   * currently saved in storage).
   * @dev Reverts if domains or connectors do not match, including ordering.
   * @param _connectors The given connectors array to check.
   */
  function validateConnectors(address[] calldata _connectors) public view {
    // Validate that given connectors match the current array in storage.
    require(keccak256(abi.encode(_connectors)) == connectorsHash, "!connectors");
  }

  // ============ Helper Functions ============

  /**
   * @notice Handles all mutex for adding support for a given domain.
   * @param _domain Domain for which we are adding support.
   * @param _connector Corresponding hub connector address belonging to given domain.
   */
  function addDomain(uint32 _domain, address _connector) internal {
    // Sanity check: domain does not already exist.
    require(!isDomainSupported(_domain), "exists");
    // Sanity check: connector is reasonable.
    require(_connector != address(0), "!connector");
    // Sanity check: Under maximum.
    require(domains.length < MAX_DOMAINS, "DomainIndexer at capacity");

    // Push domain and connector to respective arrays.
    domains.push(_domain);
    connectors.push(_connector);
    // Set reverse lookup.
    uint256 _indexPlusOne = domains.length;
    domainToIndexPlusOne[_domain] = _indexPlusOne;

    // Update the hashes for the given arrays.
    updateHashes();

    emit DomainAdded(_domain, _connector);
  }

  /**
   * @notice Handles all mutex for removing support for a given domain.
   * @param _domain Domain we are removing.
   * @return address of the hub connector for the domain we removed.
   */
  function removeDomain(uint32 _domain) internal returns (address) {
    uint256 _index = getDomainIndex(_domain);
    // Get the connector at the given index.
    address _connector = connectors[_index];
    // Sanity check: connector exists.
    require(_connector != address(0), "connector !exists");

    // Shortcut: is the index the last index in the domains/connectors arrays?
    // IFF not, we'll need to swap the target with the current last so we can pop().
    uint256 _lastIndex = domains.length - 1;
    if (_index < _lastIndex) {
      // If the target index for removal is not the last index, we'll need to move the last index
      // item to the target index's place so we can conveniently pop the last item.
      // Replace domain in domains array with the domain in the final index.
      domains[_index] = domains[_lastIndex];
      connectors[_index] = connectors[_lastIndex];
    }

    // Pop the last item in the arrays.
    domains.pop();
    connectors.pop();
    // Erase reverse lookup.
    delete domainToIndexPlusOne[_domain];

    // Update the hashes for the given arrays.
    updateHashes();

    emit DomainRemoved(_domain);

    return _connector;
  }

  /**
   * @notice Calculate the new hashes for the domains and connectors arrays and update storage refs.
   * @dev Used for the Connector update functions `addConnector`, `removeConnector`.
   */
  function updateHashes() internal {
    uint32[] memory _domains = domains;
    address[] memory _connectors = connectors;
    domainsHash = keccak256(abi.encode(_domains));
    connectorsHash = keccak256(abi.encode(_connectors));
  }
}

// File: contracts/messaging/libraries/MerkleLib.sol



// SPDX-License-Identifier: MIT OR Apache-2.0
pragma solidity 0.8.17;

/**
 * @title MerkleLib
 * @author Illusory Systems Inc.
 * @notice An incremental merkle tree modeled on the eth2 deposit contract.
 **/
library MerkleLib {
  // ========== Custom Errors ===========

  error MerkleLib__insert_treeIsFull();

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

  uint256 internal constant TREE_DEPTH = 32;
  uint256 internal constant MAX_LEAVES = 2**TREE_DEPTH - 1;

  /**
   * @dev Z_i represent the hash values at different heights for a binary tree with leaf values equal to `0`.
   * (e.g. Z_1 is the keccak256 hash of (0x0, 0x0), Z_2 is the keccak256 hash of (Z_1, Z_1), etc...)
   * Z_0 is the bottom of the 33-layer tree, Z_32 is the top (i.e. root).
   * Used to shortcut calculation in root calculation methods below.
   */
  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";
  bytes32 internal constant Z_32 = hex"27ae5ba08d7291c96c8cbddcc148bf48a6d68c7974b94356f53754ef6171d757";

  // ============= Structs ==============

  /**
   * @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;
  }

  // ========= Write Methods =========

  /**
   * @notice Inserts a given node (leaf) into merkle tree. Operates on an in-memory tree and
   * returns an updated version of that tree.
   * @dev Reverts if the tree is already full.
   * @param node Element to insert into tree.
   * @return Tree Updated tree.
   **/
  function insert(Tree memory tree, bytes32 node) internal pure returns (Tree memory) {
    // Update tree.count to increase the current count by 1 since we'll be including a new node.
    uint256 size = ++tree.count;
    if (size > MAX_LEAVES) revert MerkleLib__insert_treeIsFull();

    // Loop starting at 0, ending when we've finished inserting the node (i.e. hashing it) into
    // the active branch. Each loop we cut size in half, hashing the inserted node up the active
    // branch along the way.
    for (uint256 i; i < TREE_DEPTH; ) {
      // Check if the current size is odd; if so, we set this index in the branch to be the node.
      if ((size & 1) == 1) {
        // If i > 0, then this node will be a hash of the original node with every layer up
        // until layer `i`.
        tree.branch[i] = node;
        return tree;
      }
      // If the size is not yet odd, we hash the current index in the tree branch with the node.
      node = keccak256(abi.encodePacked(tree.branch[i], node));
      size >>= 1; // Cut size in half (statement equivalent to: `size /= 2`).

      unchecked {
        ++i;
      }
    }
    // As the loop should always end prematurely with the `return` statement, this code should
    // be unreachable. We revert here just to be safe.
    revert MerkleLib__insert_treeIsFull();
  }

  // ========= Read Methods =========

  /**
   * @notice Calculates and returns tree's current root.
   * @return _current bytes32 root.
   **/
  function root(Tree storage tree) internal view returns (bytes32 _current) {
    uint256 _index = tree.count;

    if (_index == 0) {
      return Z_32;
    }

    uint256 i;
    assembly {
      let TREE_SLOT := tree.slot

      for {

      } true {

      } {
        for {

        } true {

        } {
          if and(_index, 1) {
            mstore(0, sload(TREE_SLOT))
            mstore(0x20, Z_0)
            _current := keccak256(0, 0x40)
            break
          }

          if and(_index, shl(1, 1)) {
            mstore(0, sload(add(TREE_SLOT, 1)))
            mstore(0x20, Z_1)
            _current := keccak256(0, 0x40)
            i := 1
            break
          }

          if and(_index, shl(2, 1)) {
            mstore(0, sload(add(TREE_SLOT, 2)))
            mstore(0x20, Z_2)
            _current := keccak256(0, 0x40)
            i := 2
            break
          }

          if and(_index, shl(3, 1)) {
            mstore(0, sload(add(TREE_SLOT, 3)))
            mstore(0x20, Z_3)
            _current := keccak256(0, 0x40)
            i := 3
            break
          }

          if and(_index, shl(4, 1)) {
            mstore(0, sload(add(TREE_SLOT, 4)))
            mstore(0x20, Z_4)
            _current := keccak256(0, 0x40)
            i := 4
            break
          }

          if and(_index, shl(5, 1)) {
            mstore(0, sload(add(TREE_SLOT, 5)))
            mstore(0x20, Z_5)
            _current := keccak256(0, 0x40)
            i := 5
            break
          }

          if and(_index, shl(6, 1)) {
            mstore(0, sload(add(TREE_SLOT, 6)))
            mstore(0x20, Z_6)
            _current := keccak256(0, 0x40)
            i := 6
            break
          }

          if and(_index, shl(7, 1)) {
            mstore(0, sload(add(TREE_SLOT, 7)))
            mstore(0x20, Z_7)
            _current := keccak256(0, 0x40)
            i := 7
            break
          }

          if and(_index, shl(8, 1)) {
            mstore(0, sload(add(TREE_SLOT, 8)))
            mstore(0x20, Z_8)
            _current := keccak256(0, 0x40)
            i := 8
            break
          }

          if and(_index, shl(9, 1)) {
            mstore(0, sload(add(TREE_SLOT, 9)))
            mstore(0x20, Z_9)
            _current := keccak256(0, 0x40)
            i := 9
            break
          }

          if and(_index, shl(10, 1)) {
            mstore(0, sload(add(TREE_SLOT, 10)))
            mstore(0x20, Z_10)
            _current := keccak256(0, 0x40)
            i := 10
            break
          }

          if and(_index, shl(11, 1)) {
            mstore(0, sload(add(TREE_SLOT, 11)))
            mstore(0x20, Z_11)
            _current := keccak256(0, 0x40)
            i := 11
            break
          }

          if and(_index, shl(12, 1)) {
            mstore(0, sload(add(TREE_SLOT, 12)))
            mstore(0x20, Z_12)
            _current := keccak256(0, 0x40)
            i := 12
            break
          }

          if and(_index, shl(13, 1)) {
            mstore(0, sload(add(TREE_SLOT, 13)))
            mstore(0x20, Z_13)
            _current := keccak256(0, 0x40)
            i := 13
            break
          }

          if and(_index, shl(14, 1)) {
            mstore(0, sload(add(TREE_SLOT, 14)))
            mstore(0x20, Z_14)
            _current := keccak256(0, 0x40)
            i := 14
            break
          }

          if and(_index, shl(15, 1)) {
            mstore(0, sload(add(TREE_SLOT, 15)))
            mstore(0x20, Z_15)
            _current := keccak256(0, 0x40)
            i := 15
            break
          }

          if and(_index, shl(16, 1)) {
            mstore(0, sload(add(TREE_SLOT, 16)))
            mstore(0x20, Z_16)
            _current := keccak256(0, 0x40)
            i := 16
            break
          }

          if and(_index, shl(17, 1)) {
            mstore(0, sload(add(TREE_SLOT, 17)))
            mstore(0x20, Z_17)
            _current := keccak256(0, 0x40)
            i := 17
            break
          }

          if and(_index, shl(18, 1)) {
            mstore(0, sload(add(TREE_SLOT, 18)))
            mstore(0x20, Z_18)
            _current := keccak256(0, 0x40)
            i := 18
            break
          }

          if and(_index, shl(19, 1)) {
            mstore(0, sload(add(TREE_SLOT, 19)))
            mstore(0x20, Z_19)
            _current := keccak256(0, 0x40)
            i := 19
            break
          }

          if and(_index, shl(20, 1)) {
            mstore(0, sload(add(TREE_SLOT, 20)))
            mstore(0x20, Z_20)
            _current := keccak256(0, 0x40)
            i := 20
            break
          }

          if and(_index, shl(21, 1)) {
            mstore(0, sload(add(TREE_SLOT, 21)))
            mstore(0x20, Z_21)
            _current := keccak256(0, 0x40)
            i := 21
            break
          }

          if and(_index, shl(22, 1)) {
            mstore(0, sload(add(TREE_SLOT, 22)))
            mstore(0x20, Z_22)
            _current := keccak256(0, 0x40)
            i := 22
            break
          }

          if and(_index, shl(23, 1)) {
            mstore(0, sload(add(TREE_SLOT, 23)))
            mstore(0x20, Z_23)
            _current := keccak256(0, 0x40)
            i := 23
            break
          }

          if and(_index, shl(24, 1)) {
            mstore(0, sload(add(TREE_SLOT, 24)))
            mstore(0x20, Z_24)
            _current := keccak256(0, 0x40)
            i := 24
            break
          }

          if and(_index, shl(25, 1)) {
            mstore(0, sload(add(TREE_SLOT, 25)))
            mstore(0x20, Z_25)
            _current := keccak256(0, 0x40)
            i := 25
            break
          }

          if and(_index, shl(26, 1)) {
            mstore(0, sload(add(TREE_SLOT, 26)))
            mstore(0x20, Z_26)
            _current := keccak256(0, 0x40)
            i := 26
            break
          }

          if and(_index, shl(27, 1)) {
            mstore(0, sload(add(TREE_SLOT, 27)))
            mstore(0x20, Z_27)
            _current := keccak256(0, 0x40)
            i := 27
            break
          }

          if and(_index, shl(28, 1)) {
            mstore(0, sload(add(TREE_SLOT, 28)))
            mstore(0x20, Z_28)
            _current := keccak256(0, 0x40)
            i := 28
            break
          }

          if and(_index, shl(29, 1)) {
            mstore(0, sload(add(TREE_SLOT, 29)))
            mstore(0x20, Z_29)
            _current := keccak256(0, 0x40)
            i := 29
            break
          }

          if and(_index, shl(30, 1)) {
            mstore(0, sload(add(TREE_SLOT, 30)))
            mstore(0x20, Z_30)
            _current := keccak256(0, 0x40)
            i := 30
            break
          }

          if and(_index, shl(31, 1)) {
            mstore(0, sload(add(TREE_SLOT, 31)))
            mstore(0x20, Z_31)
            _current := keccak256(0, 0x40)
            i := 31
            break
          }

          _current := Z_32
          i := 32
          break
        }

        if gt(i, 30) {
          break
        }

        {
          if lt(i, 1) {
            switch and(_index, shl(1, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_1)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 1)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 2) {
            switch and(_index, shl(2, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_2)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 2)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 3) {
            switch and(_index, shl(3, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_3)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 3)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 4) {
            switch and(_index, shl(4, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_4)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 4)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 5) {
            switch and(_index, shl(5, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_5)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 5)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 6) {
            switch and(_index, shl(6, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_6)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 6)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 7) {
            switch and(_index, shl(7, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_7)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 7)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 8) {
            switch and(_index, shl(8, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_8)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 8)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 9) {
            switch and(_index, shl(9, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_9)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 9)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 10) {
            switch and(_index, shl(10, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_10)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 10)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 11) {
            switch and(_index, shl(11, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_11)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 11)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 12) {
            switch and(_index, shl(12, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_12)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 12)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 13) {
            switch and(_index, shl(13, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_13)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 13)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 14) {
            switch and(_index, shl(14, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_14)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 14)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 15) {
            switch and(_index, shl(15, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_15)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 15)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 16) {
            switch and(_index, shl(16, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_16)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 16)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 17) {
            switch and(_index, shl(17, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_17)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 17)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 18) {
            switch and(_index, shl(18, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_18)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 18)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 19) {
            switch and(_index, shl(19, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_19)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 19)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 20) {
            switch and(_index, shl(20, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_20)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 20)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 21) {
            switch and(_index, shl(21, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_21)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 21)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 22) {
            switch and(_index, shl(22, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_22)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 22)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 23) {
            switch and(_index, shl(23, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_23)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 23)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 24) {
            switch and(_index, shl(24, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_24)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 24)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 25) {
            switch and(_index, shl(25, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_25)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 25)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 26) {
            switch and(_index, shl(26, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_26)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 26)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 27) {
            switch and(_index, shl(27, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_27)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 27)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 28) {
            switch and(_index, shl(28, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_28)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 28)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 29) {
            switch and(_index, shl(29, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_29)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 29)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 30) {
            switch and(_index, shl(30, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_30)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 30)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }

          if lt(i, 31) {
            switch and(_index, shl(31, 1))
            case 0 {
              mstore(0, _current)
              mstore(0x20, Z_31)
            }
            default {
              mstore(0, sload(add(TREE_SLOT, 31)))
              mstore(0x20, _current)
            }

            _current := keccak256(0, 0x40)
          }
        }

        break
      }
    }
  }

  /**
   * @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) {
    assembly {
      _current := _item
      let BRANCH_DATA_OFFSET := _branch
      let f

      f := shl(5, and(_index, 1))
      mstore(f, _current)
      mstore(sub(0x20, f), mload(BRANCH_DATA_OFFSET))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(1, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 1))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(2, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 2))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(3, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 3))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(4, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 4))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(5, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 5))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(6, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 6))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(7, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 7))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(8, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 8))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(9, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 9))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(10, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 10))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(11, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 11))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(12, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 12))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(13, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 13))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(14, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 14))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(15, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 15))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(16, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 16))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(17, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 17))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(18, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 18))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(19, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 19))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(20, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 20))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(21, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 21))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(22, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 22))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(23, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 23))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(24, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 24))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(25, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 25))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(26, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 26))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(27, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 27))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(28, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 28))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(29, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 29))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(30, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 30))))
      _current := keccak256(0, 0x40)

      f := shl(5, iszero(and(_index, shl(31, 1))))
      mstore(sub(0x20, f), _current)
      mstore(f, mload(add(BRANCH_DATA_OFFSET, shl(5, 31))))
      _current := keccak256(0, 0x40)
    }
  }
}

// File: contracts/messaging/libraries/Queue.sol



// SPDX-License-Identifier: MIT OR Apache-2.0
pragma solidity 0.8.17;

/**
 * @title QueueLib
 * @notice Library containing queue struct and operations for queue used by RootManager and SpokeConnector
 * for handling the verification period. Tracks both message data itself and the block that the message was
 * committed to the queue.
 **/
library QueueLib {
  /**
   * @notice Queue struct
   * @dev Internally keeps track of the `first` and `last` elements through
   * indices and a mapping of indices to enqueued elements.
   **/
  struct Queue {
    uint128 first;
    uint128 last;
    // Message data (roots) that have been received.
    mapping(uint256 => bytes32) data;
    // The block that the message data was committed.
    mapping(uint256 => uint256) commitBlock;
    // A reverse mapping of all entries that have been "removed" by value; behaves like a blocklist.
    // NOTE: Removed values can still be pushed to the queue, but will be ignored/skipped when dequeuing.
    mapping(bytes32 => bool) removed;
  }

  /**
   * @notice Initializes the queue
   * @dev Empty state denoted by queue.first > queue.last. Queue initialized with
   * queue.first = 1 and queue.last = 0.
   **/
  function initialize(Queue storage queue) internal {
    queue.first = 1;
    delete queue.last;
  }

  /**
   * @notice Enqueues a single new element and records block number that the item was enqueued
   * (i.e. current block).
   * @param item New element to be enqueued.
   * @return last Index of newly enqueued element.
   **/
  function enqueue(Queue storage queue, bytes32 item) internal returns (uint128 last) {
    // Commit block is the block we are committing this item to the queue.
    uint256 commitBlock = block.number;
    // Increment `last` position.
    last = ++queue.last;
    // Add the item and record block number.
    queue.data[last] = item;
    queue.commitBlock[last] = commitBlock;
  }

  /**
   * @notice Dequeues element at front of queue if it exists AND it's surpassed the given
   * verification period (i.e. has been sitting in the queue for enough blocks).
   * @param queue QueueStorage struct from contract.
   * @param delay The required delay that must have been surpassed in order to merit dequeuing
   * the element.
   * @param max The maximum number of elements we are allowed to dequeue in this call.
   * @return item Dequeued element IFF delay period has been surpassed; otherwise, empty bytes32.
   **/
  function dequeueVerified(
    Queue storage queue,
    uint256 delay,
    uint128 max
  ) internal returns (bytes32[] memory) {
    uint128 first = queue.first;
    uint128 last = queue.last;

    // If queue is empty, short-circuit here.
    if (last < first) {
      return new bytes32[](0);
    }

    // Input sanity checks.
    require(first != 0, "queue !init'd");
    require(max > 0, "!acceptable max");

    {
      // If we would otherwise be searching beyond the maximum amount we are allowed to dequeue in this
      // call, reduce `last` to artificially shrink the available queue within the scope of this method.
      uint128 highestAllowed = first + max - 1;
      if (last > highestAllowed) {
        last = highestAllowed;
      }
    }

    // Commit block must be below this block to be considered verified.
    // NOTE: It's assumed that block number is a higher value than delay (i.e. delay is reasonable).
    uint256 highestAcceptableCommitBlock = block.number - delay;

    // To determine the last item index in the queue we want to return, iterate backwards until we
    // find a `commitBlock` that has surpassed the delay period.
    // TODO: The most efficient way to determine the split index here should be using a binary search.
    bool containsVerified;
    // NOTE: `first <= last` rephrased here to `!(first > last)` as it's a cheaper condition.
    while (!(first > last)) {
      uint256 commitBlock = queue.commitBlock[last];
      // NOTE: Same as `commitBlock <= highestAcceptableCommitBlock`.
      if (!(commitBlock > highestAcceptableCommitBlock)) {
        containsVerified = true;
        break;
      }
      unchecked {
        --last;
      }
    }
    // IFF no verified items were found, then we can return an empty array.
    if (!containsVerified) {
      return new bytes32[](0);
    }

    bytes32[] memory items = new bytes32[](last + 1 - first);
    uint256 index; // Cursor for index in the batch of `items`.
    uint256 removedCount; // If any items have been removed, we filter them here.
    // NOTE: `first <= last` rephrased here to `!(first > last)` as it's a cheaper condition.
    while (!(first > last)) {
      bytes32 item = queue.data[first];
      // Check to see if the item has been removed before appending it to the array.
      if (!queue.removed[item]) {
        items[index] = item;
        unchecked {
          ++index;
        }
      } else {
        // The item was removed. We do NOT increment the index (we will re-use this position).
        unchecked {
          ++removedCount;
        }
      }

      // Delete the item and the commitBlock.
      // NOTE: We do NOT delete the entry from `queue.removed`, as it's a reverse lookup and we want to
      // block that value permanently (e.g. if there's multiple of the same bad value in the queue).
      delete queue.data[first];
      delete queue.commitBlock[first];

      unchecked {
        ++first;
      }
    }

    // Update the value for `first` in our queue object since we've dequeued a number of elements.
    queue.first = first;

    if (removedCount == 0) {
      return items;
    } else {
      // If some items were removed, there will be a number of trailing 0 values we need to truncate
      // from the array. Create a new array with all of the items up until these empty values.
      bytes32[] memory amendedItems = new bytes32[](index); // The last `index` is the new length.
      for (uint256 i; i < index; ) {
        amendedItems[i] = items[i];
        unchecked {
          ++i;
        }
      }
      return amendedItems;
    }
  }

  /**
   * @notice Sets a certain value to be ignored (skipped) when dequeuing.
   */
  function remove(Queue storage queue, bytes32 item) internal {
    require(!queue.removed[item], "already removed");
    queue.removed[item] = true;
  }

  /**
   * @notice Check whether the queue is empty.
   * @param queue QueueStorage struct from contract.
   * @return bool True if queue is empty and false if otherwise.
   */
  function isEmpty(Queue storage queue) internal view returns (bool) {
    return queue.last < queue.first;
  }

  /**
   * @notice Returns number of elements in queue.
   * @param queue QueueStorage struct from contract.
   */
  function length(Queue storage queue) internal view returns (uint256) {
    uint128 last = queue.last;
    uint128 first = queue.first;
    // Cannot underflow unless state is corrupted.
    return _length(last, first);
  }

  /**
   * @notice Returns number of elements between `last` and `first` (used internally).
   * @param last The last element index.
   * @param first The first element index.
   */
  function _length(uint128 last, uint128 first) internal pure returns (uint256) {
    return uint256(last + 1 - first);
  }
}

// File: contracts/shared/ProposedOwnable.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity 0.8.17;

import {IProposedOwnable} from "./interfaces/IProposedOwnable.sol";

/**
 * @title ProposedOwnable
 * @notice 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 via a two step process:
 * 1. Call `proposeOwner`
 * 2. Wait out the delay period
 * 3. Call `acceptOwner`
 *
 * @dev 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.
 *
 * @dev The majority of this code was taken from the openzeppelin Ownable
 * contract
 *
 */
abstract contract ProposedOwnable is IProposedOwnable {
  // ========== Custom Errors ===========

  error ProposedOwnable__onlyOwner_notOwner();
  error ProposedOwnable__onlyProposed_notProposedOwner();
  error ProposedOwnable__ownershipDelayElapsed_delayNotElapsed();
  error ProposedOwnable__proposeNewOwner_invalidProposal();
  error ProposedOwnable__proposeNewOwner_noOwnershipChange();
  error ProposedOwnable__renounceOwnership_noProposal();
  error ProposedOwnable__renounceOwnership_invalidProposal();

  // ============ Properties ============

  address private _owner;

  address private _proposed;
  uint256 private _proposedOwnershipTimestamp;

  uint256 private constant _delay = 7 days;

  // ======== Getters =========

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

  /**
   * @notice Returns the address of the proposed owner.
   */
  function proposed() public view virtual returns (address) {
    return _proposed;
  }

  /**
   * @notice Returns the address of the proposed owner.
   */
  function proposedTimestamp() public view virtual returns (uint256) {
    return _proposedOwnershipTimestamp;
  }

  /**
   * @notice Returns the delay period before a new owner can be accepted.
   */
  function delay() public view virtual returns (uint256) {
    return _delay;
  }

  /**
   * @notice Throws if called by any account other than the owner.
   */
  modifier onlyOwner() {
    if (_owner != msg.sender) revert ProposedOwnable__onlyOwner_notOwner();
    _;
  }

  /**
   * @notice Throws if called by any account other than the proposed owner.
   */
  modifier onlyProposed() {
    if (_proposed != msg.sender) revert ProposedOwnable__onlyProposed_notProposedOwner();
    _;
  }

  /**
   * @notice Throws if the ownership delay has not elapsed
   */
  modifier ownershipDelayElapsed() {
    // Ensure delay has elapsed
    if ((block.timestamp - _proposedOwnershipTimestamp) <= _delay)
      revert ProposedOwnable__ownershipDelayElapsed_delayNotElapsed();
    _;
  }

  /**
   * @notice Indicates if the ownership has been renounced() by
   * checking if current owner is address(0)
   */
  function renounced() public view returns (bool) {
    return _owner == address(0);
  }

  // ======== External =========

  /**
   * @notice Sets the timestamp for an owner to be proposed, and sets the
   * newly proposed owner as step 1 in a 2-step process
   */
  function proposeNewOwner(address newlyProposed) public virtual onlyOwner {
    // Contract as source of truth
    if (_proposed == newlyProposed && _proposedOwnershipTimestamp != 0)
      revert ProposedOwnable__proposeNewOwner_invalidProposal();

    // Sanity check: reasonable proposal
    if (_owner == newlyProposed) revert ProposedOwnable__proposeNewOwner_noOwnershipChange();

    _setProposed(newlyProposed);
  }

  /**
   * @notice Renounces ownership of the contract after a delay
   */
  function renounceOwnership() public virtual onlyOwner ownershipDelayElapsed {
    // Ensure there has been a proposal cycle started
    if (_proposedOwnershipTimestamp == 0) revert ProposedOwnable__renounceOwnership_noProposal();

    // Require proposed is set to 0
    if (_proposed != address(0)) revert ProposedOwnable__renounceOwnership_invalidProposal();

    // Emit event, set new owner, reset timestamp
    _setOwner(address(0));
  }

  /**
   * @notice Transfers ownership of the contract to a new account (`newOwner`).
   * Can only be called by the current owner.
   */
  function acceptProposedOwner() public virtual onlyProposed ownershipDelayElapsed {
    // NOTE: no need to check if _owner == _proposed, because the _proposed
    // is 0-d out and this check is implicitly enforced by modifier

    // NOTE: no need to check if _proposedOwnershipTimestamp > 0 because
    // the only time this would happen is if the _proposed was never
    // set (will fail from modifier) or if the owner == _proposed (checked
    // above)

    // Emit event, set new owner, reset timestamp
    _setOwner(_proposed);
  }

  // ======== Internal =========

  function _setOwner(address newOwner) internal {
    emit OwnershipTransferred(_owner, newOwner);
    _owner = newOwner;
    delete _proposedOwnershipTimestamp;
    delete _proposed;
  }

  function _setProposed(address newlyProposed) private {
    _proposedOwnershipTimestamp = block.timestamp;
    _proposed = newlyProposed;
    emit OwnershipProposed(newlyProposed);
  }
}

// File: contracts/shared/ProposedOwnableUpgradeable.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity 0.8.17;

import {Initializable} from "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";

import {ProposedOwnable} from "./ProposedOwnable.sol";

abstract contract ProposedOwnableUpgradeable is Initializable, ProposedOwnable {
  /**
   * @dev Initializes the contract setting the deployer as the initial
   */
  function __ProposedOwnable_init() internal onlyInitializing {
    __ProposedOwnable_init_unchained();
  }

  function __ProposedOwnable_init_unchained() internal onlyInitializing {
    _setOwner(msg.sender);
  }

  /**
   * @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[47] private __GAP;
}

// File: contracts/shared/interfaces/IProposedOwnable.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.17;

/**
 * @title IProposedOwnable
 * @notice Defines a minimal interface for ownership with a two step proposal and acceptance
 * process
 */
interface IProposedOwnable {
  /**
   * @dev This emits when change in ownership of a contract is proposed.
   */
  event OwnershipProposed(address indexed proposedOwner);

  /**
   * @dev This emits when ownership of a contract changes.
   */
  event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

  /**
   * @notice Get the address of the owner
   * @return owner_ The address of the owner.
   */
  function owner() external view returns (address owner_);

  /**
   * @notice Get the address of the proposed owner
   * @return proposed_ The address of the proposed.
   */
  function proposed() external view returns (address proposed_);

  /**
   * @notice Set the address of the proposed owner of the contract
   * @param newlyProposed The proposed new owner of the contract
   */
  function proposeNewOwner(address newlyProposed) external;

  /**
   * @notice Set the address of the proposed owner of the contract
   */
  function acceptProposedOwner() external;
}