// File: @openzeppelin/contracts/access/Ownable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)

pragma solidity ^0.8.0;

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

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

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

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

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

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

// File: @openzeppelin/contracts/security/Pausable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (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 Returns true if the contract is paused, and false otherwise.
     */
    function paused() public view virtual returns (bool) {
        return _paused;
    }

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

    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    modifier whenPaused() {
        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/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

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

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

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

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

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

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

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

// 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/Withdrawal.sol



// SPDX-License-Identifier: MIT
pragma solidity =0.8.7;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/security/Pausable.sol";
import "@openzeppelin/contracts/access/Ownable.sol";

contract Withdrawal is Pausable, Ownable {
    event WithdrawalEvent(uint256 indexed key, address signer, address to, address indexed token, uint256 amount);
    event CancelEvent(uint256 indexed key, address signer, address to, address indexed token, uint256 amount);
    event UpdateSigner(address signer, bool value);
    event UpdatePauseOperator(address oldOperator, address newOperator);

    enum OrderStatus {
        None,
        Processed,
        Cancelled
    }

    /* An ECDSA signature. */
    struct Sig {
        uint8 v;
        bytes32 r;
        bytes32 s;
    }

    struct Order {
        address signer;
        address holder;
        address to;
        address token;
        uint256 amount;
        uint256 expiration;
        uint256 key;
    }

    mapping(uint256 => OrderStatus) private _status;
    mapping(uint256 => Order) public orders;
    mapping(address => bool) public allowedSigners;
    address public pauseOperator;

    error ExpiredOrder();
    error ProcessedOrder();
    error CancelledOrder();
    error InvalidOrder();
    error InvalidCaller();
    error InvalidSigner();

    modifier onlyPauseOperator() {
        if (msg.sender != pauseOperator) revert InvalidCaller();
        _;
    }

    constructor(address pauseOperator_) {
        pauseOperator = pauseOperator_;
    }

    function pause() external onlyPauseOperator {
        _pause();
    }

    function unpause() external onlyPauseOperator {
        _unpause();
    }

    function setAllowedSigner(address signer, bool value) external onlyOwner {
        allowedSigners[signer] = value;
        emit UpdateSigner(signer, value);
    }

    function setPauseOperator(address pauseOperator_) external onlyOwner {
        address oldpauseOperator = pauseOperator;
        pauseOperator = pauseOperator_;
        emit UpdatePauseOperator(oldpauseOperator, pauseOperator_);
    }

    function _getCompletedKey(Order memory order) internal pure returns (uint256) {
        return order.key;
    }

    function withdrawal(Order calldata order, Sig calldata sig) external whenNotPaused {
        validateOrder(order, sig);
        if (order.expiration <= block.timestamp) revert ExpiredOrder();
        uint256 key = _getCompletedKey(order);
        if (_status[key] == OrderStatus.Processed) revert ProcessedOrder();
        if (_status[key] == OrderStatus.Cancelled) revert CancelledOrder();

        _status[key] = OrderStatus.Processed;
        IERC20(order.token).transferFrom(order.holder, order.to, order.amount);
        emit WithdrawalEvent(order.key, order.signer, order.to, order.token, order.amount);
    }

    function cancel(Order calldata order, Sig calldata sig) external whenNotPaused {
        validateOrder(order, sig);
        uint256 key = _getCompletedKey(order);
        if (_status[key] == OrderStatus.Processed) revert ProcessedOrder();
        if (_status[key] == OrderStatus.Cancelled) revert CancelledOrder();

        _status[key] = OrderStatus.Cancelled;
        emit CancelEvent(order.key, order.signer, order.to, order.token, order.amount);
    }

    ///@dev This function will be used in the future
    // function multipleWithdrawal(Order[] calldata order, Sig[] calldata sig) external {
    //     for (uint256 i = 0; i < order.length; i++) {
    //         withdrawal(order[i], sig[i]);
    //     }
    // }

    function validateOrder(Order calldata order, Sig calldata sig) private view {
        bytes32 payloadHash = keccak256(
            abi.encode(order.signer, order.holder, order.to, order.token, order.amount, order.expiration, order.key)
        );
        bytes32 messageHash = keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", payloadHash));

        address actualSigner = ecrecover(messageHash, sig.v, sig.r, sig.s);
        if (order.signer != actualSigner) revert InvalidOrder();
        if (!allowedSigners[actualSigner]) revert InvalidSigner();
    }

    function getCompletedKey(Order calldata order) external pure returns (uint256) {
        return _getCompletedKey(order);
    }

    function getStatus(uint256 key) external view returns (OrderStatus) {
        return _status[key];
    }

    function getOrder(uint256 key) external view returns (Order memory) {
        return orders[key];
    }
}