// File: @openzeppelin\contracts\proxy\beacon\IBeacon.sol

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (proxy/beacon/IBeacon.sol)

pragma solidity ^0.8.0;

/**
 * @dev This is the interface that {BeaconProxy} expects of its beacon.
 */
interface IBeacon {
    /**
     * @dev Must return an address that can be used as a delegate call target.
     *
     * {BeaconProxy} will check that this address is a contract.
     */
    function implementation() external view returns (address);
}

// File: @openzeppelin\contracts\utils\Context.sol

// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

// File: @openzeppelin\contracts\access\Ownable.sol

// OpenZeppelin Contracts (last updated v4.9.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby disabling any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// File: @openzeppelin\contracts\utils\Address.sol

// OpenZeppelin Contracts (last updated v4.9.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     *
     * Furthermore, `isContract` will also return true if the target contract within
     * the same transaction is already scheduled for destruction by `SELFDESTRUCT`,
     * which only has an effect at the end of a transaction.
     * ====
     *
     * [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://consensys.net/diligence/blog/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/v0.8.0/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
     * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
     *
     * _Available since v4.8._
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                // only check isContract if the call was successful and the return data is empty
                // otherwise we already know that it was a contract
                require(isContract(target), "Address: call to non-contract");
            }
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    /**
     * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason or using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    function _revert(bytes memory returndata, string memory errorMessage) private pure {
        // Look for revert reason and bubble it up if present
        if (returndata.length > 0) {
            // The easiest way to bubble the revert reason is using memory via assembly
            /// @solidity memory-safe-assembly
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert(errorMessage);
        }
    }
}

// File: contracts\Beacon\UpgradeableBeaconMultisig.sol

// OpenZeppelin Contracts v4.4.1 (proxy/beacon/UpgradeableBeacon.sol)

pragma solidity ^0.8.0;



/**
 * @dev This contract is used in conjunction with one or more instances of {BeaconProxy} to determine their
 * implementation contract, which is where they will delegate all function calls.
 *
 * An owner is able to change the implementation the beacon points to, thus upgrading the proxies that use this beacon.
 */
contract UpgradeableBeaconMultisig is IBeacon, Ownable {
    event SignerChangeRequested(address indexed currentSigner, address indexed newSigner);
    event SignerUpdated(address indexed oldSigner, address indexed newSigner);
    event ImplChangeRequested(address indexed owner, address indexed newImpl);
    event Confirmation(address indexed sender, address indexed newImpl);

    uint constant public MAX_OWNER_COUNT = 10;
    mapping(address => bool) public isSigner;
    mapping(address => address) public signerChangeRequests;
    mapping(address => mapping(address => bool)) public signerChangeConfirmations;
    mapping(address => mapping(address => bool)) public confirmations;
    address[] public signers;

    address private _implementation;
    address public pendingNewImpl;

    uint public required;

    /**
     * @dev Emitted when the implementation returned by the beacon is changed.
     */
    event Upgraded(address indexed implementation);

    modifier signerExists(address signer) {
        require(isSigner[signer], "Signer does not exist");
        _;
    }

    modifier notConfirmed(address newImpl, address signer) {
        require(!confirmations[newImpl][signer], "New implemention already confirmed");
        _;
    }

    modifier notNull(address _address) {
        require(_address != address(0), "Address cannot be null");
        _;
    }
    
    modifier validRequirement(uint _signerCount, uint _required) {
        require(_signerCount <= MAX_OWNER_COUNT && _required <= _signerCount && _required != 0 && _signerCount != 0, "Invalid requirement");
        _;
    }
    
    /**
     * @dev Sets the address of the initial implementation, and the deployer account as the owner who can upgrade the
     * beacon.
     */
    constructor(
        address implementation_, 
        address[] memory _signers, 
        uint _required
    ) validRequirement(_signers.length, _required) {
        _setImplementation(implementation_);

        for (uint i = 0; i < _signers.length; ) {
            require(!isSigner[_signers[i]] && _signers[i] != address(0) && _signers[i] != msg.sender, "Invalid signer");
            isSigner[_signers[i]] = true;

            unchecked {
                i++;
            }
        }
        signers = _signers;
        required = _required;
    }

    /**
     * @dev Returns the current implementation address.
     */
    function implementation() public view virtual override returns (address) {
        return _implementation;
    }

    function transferOwnership(address newOwner) public override virtual onlyOwner {
        require(!isSigner[newOwner], "Ownable: new owner cannot be signer.");
        super.transferOwnership(newOwner);
    }
    function requestSignerChange(address _oldSigner, address _newSigner) external onlyOwner {
        require(isSigner[_oldSigner], "Old signer does not exist.");
        require(!isSigner[_newSigner], "New signer is already a signer.");
        require(_newSigner != owner(), "Onwer cannot be a signer.");
        
        // Clear the signerChangeConfirmations for _newSigner if a change is "in-progress"
        if (signerChangeRequests[_oldSigner] != address(0)) {
            clearSignerChangeConfirmations(signerChangeRequests[_oldSigner]);
        }

        signerChangeRequests[_oldSigner] = _newSigner;
        emit SignerChangeRequested(_oldSigner, _newSigner);
    }

    function confirmSignerChange(address _oldSigner, address _newSigner) external signerExists(msg.sender) {
        require(!signerChangeConfirmations[_newSigner][msg.sender], "You already confirmed.");
        require(signerChangeRequests[_oldSigner] == _newSigner, "New signer address invalid.");
        require(_newSigner != address(0), "No pending signer update request.");
        require(_newSigner != owner(), "Onwer cannot be a signer.");
        require(!isSigner[_newSigner], "New signer is already a signer.");

        // Confirm the update by the current signer
        signerChangeConfirmations[_newSigner][msg.sender] = true;
        
        if (isSignerChangeConfirmed(_newSigner)) {
            // Clear the signerChangeConfirmations for _newSigner
            clearSignerChangeConfirmations(_newSigner);

            signerChangeRequests[_oldSigner] = address(0);
            removeSigner(_oldSigner);
            isSigner[_newSigner] = true;
            signers.push(_newSigner);
            emit SignerUpdated(_oldSigner, _newSigner);
        }
    }
    
    function requestImplChange(address newImpl) external onlyOwner {
        if (pendingNewImpl != address(0))
            clearImplChangeConfirmations(pendingNewImpl);
        pendingNewImpl = newImpl;
        emit ImplChangeRequested(msg.sender, newImpl);
    }

    function confirmImplChange(address newImpl) public signerExists(msg.sender) notConfirmed(newImpl, msg.sender) {
        require(pendingNewImpl == newImpl, "Invalid new implementation address");
        confirmations[newImpl][msg.sender] = true;
        emit Confirmation(msg.sender, newImpl);
        if (isImplChangeConfirmed(newImpl)) {
            // Clear the signerChangeConfirmations for _newSigner
            clearImplChangeConfirmations(newImpl);
            pendingNewImpl = address(0);
            upgradeTo(newImpl);
        }
    }
    
    /**
     * @dev Sets the implementation contract address for this beacon
     *
     * Requirements:
     *
     * - `newImplementation` must be a contract.
     */
    function _setImplementation(address newImplementation) private {
        require(Address.isContract(newImplementation), "UpgradeableBeacon: implementation is not a contract");
        _implementation = newImplementation;
    }

    function isSignerChangeConfirmed(address _newSigner) internal view returns (bool) {
        uint256 signerCount = signers.length;
        uint256 count;
        mapping(address => bool) storage confirmation = signerChangeConfirmations[_newSigner];

        for (uint i = 0; i < signerCount && count < required; ) {
            if (confirmation[signers[i]]) count ++;
            
            unchecked {
                i++;
            }
        }

        return count == required;
    }

    function isImplChangeConfirmed(address _newImpl) internal view returns (bool) {
        uint256 signerCount = signers.length;
        uint256 count;
        mapping(address => bool) storage confirmation = confirmations[_newImpl];

        for (uint i = 0; i < signerCount && count < required; ) {
            if (confirmation[signers[i]]) count ++;
            
            unchecked {
                i++;
            }
        }

        return count == required;
    }

    function removeSigner(address oldSigner) internal {
        if (!isSigner[oldSigner]) return;

        uint256 signerCount = signers.length;
        for (uint i = 0; i < signerCount; ) {
            if (signers[i] == oldSigner) {
                if (i != signerCount - 1) {
                    signers[i] = signers[signerCount - 1];
                }
                signers.pop();
                isSigner[oldSigner] = false;
                break;
            }

            unchecked {
                i++;
            }
        }
    }

    function clearSignerChangeConfirmations(address _newSigner) internal {
        uint256 signerCount = signers.length;

        mapping(address => bool) storage confirmation = signerChangeConfirmations[_newSigner];

        for (uint i = 0; i < signerCount; ) {
            confirmation[signers[i]] = false;

            unchecked {
                i++;
            }
        }
    }

    function clearImplChangeConfirmations(address newImpl) internal {
        uint256 signerCount = signers.length;

        mapping(address => bool) storage confirmation = confirmations[newImpl];

        for (uint i = 0; i < signerCount; ) {
            confirmation[signers[i]] = false;

            unchecked {
                i++;
            }
        }
    }

    function upgradeTo(address newImplementation) internal {
        _setImplementation(newImplementation);
        emit Upgraded(newImplementation);
    }

}