// SPDX-License-Identifier: Apache-2.0
pragma solidity 0.8.24;
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "@openzeppelin/contracts/utils/Pausable.sol";
import {Address} from "@openzeppelin/contracts/utils/Address.sol";
interface BridgeInterface {
    /**
     * @dev reference: https://github.com/ethereum-optimism/optimism/blob/65ec61dde94ffa93342728d324fecf474d228e1f/packages/contracts-bedrock/contracts/L1/L1StandardBridge.sol#L188
     */
    function depositERC20To(
        address _l1Token,
        address _l2Token,
        address _to,
        uint256 _amount,
        uint32 _minGasLimit,
        bytes calldata _extraData
    ) external;
    /**
     * @dev reference: https://github.com/ethereum-optimism/optimism/blob/65ec61dde94ffa93342728d324fecf474d228e1f/packages/contracts-bedrock/contracts/L1/L1StandardBridge.sol#L137
     */
    function depositETHTo(address _to, uint32 _minGasLimit, bytes calldata _extraData) external payable;
}
/**
 * @title FusionLock Contract
 * @dev This contract allows users to deposit ERC20 tokens or Ether within a specified time time.
 * It provides functionalities for bridging tokens between Layer 1 (L1) and Layer 2 (L2) networks.
 * Users can also withdraw their deposited tokens after the max lock time ends.
 */
contract FusionLock is Ownable, Pausable {
    using SafeERC20 for IERC20;
    using Address for address payable;
    // Events
    event TokenAllowed(address token, TokenInfo info);
    event TokenDataChange(address l1Token, address l2Token, address l1Bridge);
    event BridgeAddress(address bridgeAddress);
    event WithdrawalTimeUpdated(uint256 endTime);
    event Deposit(address indexed depositOwner, address indexed token, uint256 amount, uint256 depositTime);
    event WithdrawToL1(address indexed owner, address indexed token, uint256 amount);
    event WithdrawToL2(
        address indexed owner, address indexed receiver, address indexed l1Token, address l2Token, uint256 amount
    );
    event SavedToken(address indexed user, address indexed token, uint256 amount);
    // Struct to hold token information.
    struct TokenInfo {
        bool isAllowed; // Flag indicating whether the token is allowed for deposit.
        address l2TokenAddress; // Address of the corresponding token on Layer 2.
        address l1BridgeAddressOverride; // Optional address to use for bridging to L2.
    }
    // Struct to hold L1 and L2 token addresses.
    struct TokenBridgingData {
        address l1TokenAddress;
        address l2TokenAddress;
        address l1BridgeAddressOverride;
    }
    // Struct to hold token information.
    struct SaveTokenData {
        address user; // user to send the funds to
        address token; // token to send
        uint256 amount; // amount to send
    }
    // State variables
    mapping(address => TokenInfo) public allowedTokens; // Mapping to track allowed ERC20 tokens and their corresponding L2 addresses.
    mapping(address => mapping(address => uint256)) public deposits; // Mapping to store deposit data: user address => token address => deposit amount.
    mapping(address => uint256) public totalDeposits; // Mapping to track total deposit amount per token address. Used for refunds in case of bridging failure.
    uint256 public withdrawalStartTime; // Start time for withdrawal
    address public bridgeProxyAddress; // Address of the bridge contract for L1-L2 token transfers
    // Constant representing the Ethereum token address.
    address public constant ETH_TOKEN_ADDRESS = address(0x00);
    /**
     * @dev Constructor
     * @param setWithdrawalStartTime Withdrawal start time
     * @param allowTokens Array of addresses representing ERC20 tokens to be allowed for deposit
     * @param initialOwner Address of the initial owner of the contract.
     */
    constructor(uint256 setWithdrawalStartTime, address[] memory allowTokens, address initialOwner)
        Ownable(initialOwner)
    {
        require(setWithdrawalStartTime > block.timestamp, "Withdrawal start time can't be historical");
        withdrawalStartTime = setWithdrawalStartTime;
        for (uint256 tokenId = 0; tokenId < allowTokens.length; tokenId++) {
            _allow(allowTokens[tokenId], address(0x00), address(0x00));
        }
        // allow eth by default
        _allow(ETH_TOKEN_ADDRESS, address(0x00), address(0x00));
    }
    /**
     * @dev Modifier to check if deposit is allowed.
     * @param amount Amount of tokens being deposited.
     */
    modifier isDepositAllowed(uint256 amount) {
        require(!isWithdrawalTimeStarted(), "Deposit time already ended");
        require(amount > 0, "Amount Should Be Greater Than Zero");
        _;
    }
    /**
     * @dev Deposit ERC20 tokens.
     * @param token Address of the ERC20 token.
     * @param amount Amount of tokens to deposit.
     */
    function depositERC20(address token, uint256 amount) external isDepositAllowed(amount) whenNotPaused {
        require(allowedTokens[token].isAllowed, "Deposit token not allowed");
        deposits[msg.sender][token] += amount;
        totalDeposits[token] += amount;
        // Transfer tokens to contract
        IERC20(token).safeTransferFrom(msg.sender, address(this), amount);
        // Emit Deposit event
        emit Deposit(msg.sender, token, amount, block.timestamp);
    }
    /**
     * @dev Deposit Ether
     * Allows users to deposit Ether into the contract.
     */
    function depositEth() external payable isDepositAllowed(msg.value) whenNotPaused {
        // Increase the deposited Ether amount for the sender.
        deposits[msg.sender][ETH_TOKEN_ADDRESS] += msg.value;
        totalDeposits[ETH_TOKEN_ADDRESS] += msg.value;
        // Emit Deposit Event
        emit Deposit(msg.sender, ETH_TOKEN_ADDRESS, msg.value, block.timestamp);
    }
    /**
     * @dev Function to withdraw ERC20 tokens or Ether for a given deposit.
     * @param token Address of the token to withdraw.
     */
    function withdrawSingleDepositToL1(address token) internal {
        uint256 transferAmount = deposits[msg.sender][token];
        require(transferAmount != 0, "Withdrawal completed or token never deposited");
        deposits[msg.sender][token] = 0;
        totalDeposits[token] -= transferAmount;
        if (token == ETH_TOKEN_ADDRESS) {
            // Note: we use openzeppelin's `sendValue` rather than `transfer` because
            // `transfer` forwards a fixed amount of gas (2300), which may not be enough
            // if msg.sender is a smart contract. We should be OK against reentrancy
            // attacks since we follow the checks-effects-interactions pattern
            payable(msg.sender).sendValue(transferAmount);
        } else {
            // Transfer ERC20 tokens to the sender.
            IERC20(token).safeTransfer(msg.sender, transferAmount);
        }
        emit WithdrawToL1(msg.sender, token, transferAmount);
    }
    /**
     * @dev Internal function to withdraw tokens to Layer 2.
     * @param token Address of the token to withdraw.
     * @param minGasLimit Minimum gas limit for each individual withdrawal transaction.
     * @param receiver The receiver of the funds on L2.
     */
    function withdrawSingleDepositToL2(address token, uint32 minGasLimit, address receiver) internal {
        uint256 transferAmount = deposits[msg.sender][token];
        require(transferAmount != 0, "Withdrawal completed or token never deposited");
        // Retrieve token information.
        TokenInfo memory tokenInfo = allowedTokens[token];
        // check l2 token address set.
        require(token == ETH_TOKEN_ADDRESS || tokenInfo.l2TokenAddress != address(0x00), "L2 token address not set");
        address bridgeAddress = bridgeProxyAddress;
        if (tokenInfo.l1BridgeAddressOverride != address(0x00)) {
            bridgeAddress = tokenInfo.l1BridgeAddressOverride;
        }
        deposits[msg.sender][token] = 0;
        totalDeposits[token] -= transferAmount;
        if (token == ETH_TOKEN_ADDRESS) {
            // Bridge Ether to Layer 2.
            BridgeInterface(bridgeAddress).depositETHTo{value: transferAmount}(receiver, minGasLimit, hex"");
        } else {
            // Approve tokens for transfer to the bridge.
            IERC20(token).approve(bridgeAddress, transferAmount);
            // Bridge ERC20 tokens to Layer 2.
            BridgeInterface(bridgeAddress).depositERC20To(
                token, tokenInfo.l2TokenAddress, receiver, transferAmount, minGasLimit, hex""
            );
        }
        emit WithdrawToL2(msg.sender, receiver, token, tokenInfo.l2TokenAddress, transferAmount);
    }
    /**
     * @dev Function to withdraw all deposits to Layer 2 for multiple tokens.
     * @param tokens Array of token addresses to withdraw.
     * @param minGasLimit Minimum gas limit for the withdrawal transactions.
     * @param receiver The receiver of the funds on L2.
     */
    function withdrawDepositsToL2(address[] memory tokens, uint32 minGasLimit, address receiver)
        external
        whenNotPaused
    {
        require(isWithdrawalTimeStarted(), "Withdrawal not started");
        // check if bridge address set
        require(bridgeProxyAddress != address(0x00), "Bridge address not set");
        // Loop through each token and withdraw to Layer 2.
        for (uint256 i = 0; i < tokens.length; i++) {
            withdrawSingleDepositToL2(tokens[i], minGasLimit, receiver);
        }
    }
    /**
     * @dev Function to withdraw all deposits to Layer 1 for multiple tokens.
     * @param tokens Array of token addresses to withdraw.
     */
    function withdrawDepositsToL1(address[] memory tokens) external {
        require(isWithdrawalTimeStarted(), "Withdrawal not started");
        // Loop through each token and withdraw to Layer 1.
        for (uint256 i = 0; i < tokens.length; i++) {
            withdrawSingleDepositToL1(tokens[i]);
        }
    }
    /**
     * @dev Function to allow ERC20 tokens for deposit.
     * This function allows the contract owner to allow specific ERC20 tokens for deposit.
     * @param l1TokenAddress Address of the ERC20 token to allow on Layer 1.
     * @param l2TokenAddress Address of the corresponding token on Layer 2.
     * @param l1BridgeAddressOverride Address of the corresponding bridge to use for this token.
     *                                Can be 0 to use the default. This should be used for tokens
     *                                that cannot use the L1StandardBridge contract. Note that the
     *                                override is expected to implement the same BridgeInterface.
     */
    function allow(address l1TokenAddress, address l2TokenAddress, address l1BridgeAddressOverride)
        external
        onlyOwner
    {
        require(!isWithdrawalTimeStarted(), "Withdrawal has started, token allowance cannot be modified");
        _allow(l1TokenAddress, l2TokenAddress, l1BridgeAddressOverride);
    }
    /**
     * @dev Internal function to allow ERC20 tokens for deposit.
     * This function updates the allowedTokens mapping with the provided token information.
     * @param l1TokenAddress Address of the ERC20 token to allow.
     * @param l2TokenAddress Address of the corresponding token on Layer 2.
     * @param l1BridgeAddressOverride Address of the corresponding bridge to use for this token.
     *                                Can be 0 to use the default.
     */
    function _allow(address l1TokenAddress, address l2TokenAddress, address l1BridgeAddressOverride) internal {
        TokenInfo memory tokenInfo = TokenInfo(true, l2TokenAddress, l1BridgeAddressOverride);
        allowedTokens[l1TokenAddress] = tokenInfo;
        emit TokenAllowed(l1TokenAddress, tokenInfo);
    }
    /**
     * @dev Function to change L2 address and the bridge address of tokens that were allowed for deposit.
     * This function allows the contract owner to change the L2 address and the L1 bridge address for tokens
     * that were previously allowed for deposit.
     * @param tokenData An array of structs, each containing the Layer 1 (L1) token address, its (L1) bridge
     *                     address, and its Layer 2 (L2) token address.
     */
    function changeMultipleL2TokenData(TokenBridgingData[] memory tokenData) external onlyOwner {
        for (uint256 i = 0; i < tokenData.length; i++) {
            TokenBridgingData memory token = tokenData[i];
            // Ensure the token is allowed for deposit before changing its L2 address
            require(allowedTokens[token.l1TokenAddress].isAllowed, "Need to allow token before changing token data");
            // Update the L2 address of the token
            allowedTokens[token.l1TokenAddress].l2TokenAddress = token.l2TokenAddress;
            allowedTokens[token.l1TokenAddress].l1BridgeAddressOverride = token.l1BridgeAddressOverride;
            emit TokenDataChange(token.l1TokenAddress, token.l2TokenAddress, token.l1BridgeAddressOverride);
        }
    }
    /**
     * @dev Function to change the withdrawal time.
     * This function allows the contract owner to change the withdrawal time.
     * @param newWithdrawalStartTime New withdrawal start time.
     */
    function changeWithdrawalTime(uint256 newWithdrawalStartTime) external onlyOwner {
        require(block.timestamp < newWithdrawalStartTime, "New timestamp can't be historical");
        require(
            withdrawalStartTime > newWithdrawalStartTime, "Withdrawal start time can only be decreased, not increased"
        );
        withdrawalStartTime = newWithdrawalStartTime;
        emit WithdrawalTimeUpdated(newWithdrawalStartTime);
    }
    /**
     * @dev Function to set the address of the bridge proxy.
     * This function allows the contract owner to set the address of the bridge proxy for token transfers between Layer 1 and Layer 2.
     * @param l2BridgeProxyAddress Address of the bridge proxy contract.
     */
    function setBridgeProxyAddress(address l2BridgeProxyAddress) external onlyOwner {
        bridgeProxyAddress = l2BridgeProxyAddress;
        emit BridgeAddress(l2BridgeProxyAddress);
    }
    /**
     * @dev This function allows the contract owner to recover ERC20 tokens that would
     * otherwise stay locked in the contract forever.
     * @param tokenData An array of structs containing information about the tokens to be saved.
     */
    function saveTokens(SaveTokenData[] calldata tokenData) external onlyOwner {
        for (uint256 i = 0; i < tokenData.length; i++) {
            saveToken(tokenData[i].user, tokenData[i].token, tokenData[i].amount);
        }
    }
    /**
     * @dev Internal function to recover an ERC20 token that would otherwise stay locked in
     * the contract forever. This function transfers the specified amount of ERC20 token
     * from the contract's balance to the specified user's address.
     * @param user Address of the user to send the tokens to.
     * @param token Address of the ERC20 token to be saved.
     * @param amount Amount of tokens to be saved.
     */
    function saveToken(address user, address token, uint256 amount) internal {
        require(
            token != ETH_TOKEN_ADDRESS,
            "Only ERC20 tokens can be recovered, since eth bridging is supposed to be infallible"
        );
        uint256 tokenBalance = IERC20(token).balanceOf(address(this));
        require(tokenBalance >= totalDeposits[token] + amount, "Insufficient balance to save token");
        IERC20(token).safeTransfer(user, amount);
        emit SavedToken(user, token, amount);
    }
    /**
     * @dev Function to pause contract. This calls the Pausable contract.
     */
    function pause() external onlyOwner {
        super._pause();
    }
    /**
     * @dev Function to unpause contract. This calls the Pausable contract.
     */
    function unpause() external onlyOwner {
        super._unpause();
    }
    /**
     * @dev Function to check if the withdrawal time has started.
     * @return bool true if the withdrawal time has started, false otherwise.
     */
    function isWithdrawalTimeStarted() public view returns (bool) {
        // Check if the withdrawal time has started.
        return block.timestamp >= withdrawalStartTime;
    }
    /**
     * @dev Get the Ether balance of the contract
     * @return uint256 Ether balance of the contract
     */
    function getEthBalance() public view returns (uint256) {
        return address(this).balance;
    }
    /**
     * @dev Function to retrieve information about a token's allowance for deposit.
     * @param token Address of the token to retrieve information for.
     */
    function getTokenInfo(address token) public view returns (TokenInfo memory) {
        return allowedTokens[token];
    }
    /**
     * @dev Get the deposited amount of a token for a given user
     * @param depositOwner Address of the user
     * @param token Address of the token
     * @return uint256 Amount of tokens deposited
     */
    function getDepositAmount(address depositOwner, address token) public view returns (uint256) {
        return deposits[depositOwner][token];
    }
    fallback() external payable {
        revert("fallback not allowed");
    }
    receive() external payable {
        revert("receive not allowed");
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (access/Ownable.sol)
pragma solidity ^0.8.20;
import {Context} from "../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.
 *
 * The initial owner is set to the address provided by the deployer. 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;
    /**
     * @dev The caller account is not authorized to perform an operation.
     */
    error OwnableUnauthorizedAccount(address account);
    /**
     * @dev The owner is not a valid owner account. (eg. `address(0)`)
     */
    error OwnableInvalidOwner(address owner);
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
    /**
     * @dev Initializes the contract setting the address provided by the deployer as the initial owner.
     */
    constructor(address initialOwner) {
        if (initialOwner == address(0)) {
            revert OwnableInvalidOwner(address(0));
        }
        _transferOwnership(initialOwner);
    }
    /**
     * @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 {
        if (owner() != _msgSender()) {
            revert OwnableUnauthorizedAccount(_msgSender());
        }
    }
    /**
     * @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 {
        if (newOwner == address(0)) {
            revert OwnableInvalidOwner(address(0));
        }
        _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);
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/utils/SafeERC20.sol)
pragma solidity ^0.8.20;
import {IERC20} from "../IERC20.sol";
import {IERC20Permit} from "../extensions/IERC20Permit.sol";
import {Address} from "../../../utils/Address.sol";
/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using Address for address;
    /**
     * @dev An operation with an ERC20 token failed.
     */
    error SafeERC20FailedOperation(address token);
    /**
     * @dev Indicates a failed `decreaseAllowance` request.
     */
    error SafeERC20FailedDecreaseAllowance(address spender, uint256 currentAllowance, uint256 requestedDecrease);
    /**
     * @dev Transfer `value` amount of `token` from the calling contract to `to`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeCall(token.transfer, (to, value)));
    }
    /**
     * @dev Transfer `value` amount of `token` from `from` to `to`, spending the approval given by `from` to the
     * calling contract. If `token` returns no value, non-reverting calls are assumed to be successful.
     */
    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeCall(token.transferFrom, (from, to, value)));
    }
    /**
     * @dev Increase the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 oldAllowance = token.allowance(address(this), spender);
        forceApprove(token, spender, oldAllowance + value);
    }
    /**
     * @dev Decrease the calling contract's allowance toward `spender` by `requestedDecrease`. If `token` returns no
     * value, non-reverting calls are assumed to be successful.
     */
    function safeDecreaseAllowance(IERC20 token, address spender, uint256 requestedDecrease) internal {
        unchecked {
            uint256 currentAllowance = token.allowance(address(this), spender);
            if (currentAllowance < requestedDecrease) {
                revert SafeERC20FailedDecreaseAllowance(spender, currentAllowance, requestedDecrease);
            }
            forceApprove(token, spender, currentAllowance - requestedDecrease);
        }
    }
    /**
     * @dev Set the calling contract's allowance toward `spender` to `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful. Meant to be used with tokens that require the approval
     * to be set to zero before setting it to a non-zero value, such as USDT.
     */
    function forceApprove(IERC20 token, address spender, uint256 value) internal {
        bytes memory approvalCall = abi.encodeCall(token.approve, (spender, value));
        if (!_callOptionalReturnBool(token, approvalCall)) {
            _callOptionalReturn(token, abi.encodeCall(token.approve, (spender, 0)));
            _callOptionalReturn(token, approvalCall);
        }
    }
    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address-functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.
        bytes memory returndata = address(token).functionCall(data);
        if (returndata.length != 0 && !abi.decode(returndata, (bool))) {
            revert SafeERC20FailedOperation(address(token));
        }
    }
    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     *
     * This is a variant of {_callOptionalReturn} that silents catches all reverts and returns a bool instead.
     */
    function _callOptionalReturnBool(IERC20 token, bytes memory data) private returns (bool) {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We cannot use {Address-functionCall} here since this should return false
        // and not revert is the subcall reverts.
        (bool success, bytes memory returndata) = address(token).call(data);
        return success && (returndata.length == 0 || abi.decode(returndata, (bool))) && address(token).code.length > 0;
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/Pausable.sol)
pragma solidity ^0.8.20;
import {Context} from "../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 {
    bool private _paused;
    /**
     * @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);
    /**
     * @dev The operation failed because the contract is paused.
     */
    error EnforcedPause();
    /**
     * @dev The operation failed because the contract is not paused.
     */
    error ExpectedPause();
    /**
     * @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 {
        if (paused()) {
            revert EnforcedPause();
        }
    }
    /**
     * @dev Throws if the contract is not paused.
     */
    function _requirePaused() internal view virtual {
        if (!paused()) {
            revert ExpectedPause();
        }
    }
    /**
     * @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());
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/Address.sol)
pragma solidity ^0.8.20;
/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev The ETH balance of the account is not enough to perform the operation.
     */
    error AddressInsufficientBalance(address account);
    /**
     * @dev There's no code at `target` (it is not a contract).
     */
    error AddressEmptyCode(address target);
    /**
     * @dev A call to an address target failed. The target may have reverted.
     */
    error FailedInnerCall();
    /**
     * @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/v0.8.20/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        if (address(this).balance < amount) {
            revert AddressInsufficientBalance(address(this));
        }
        (bool success, ) = recipient.call{value: amount}("");
        if (!success) {
            revert FailedInnerCall();
        }
    }
    /**
     * @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 or custom error, it is bubbled
     * up by this function (like regular Solidity function calls). However, if
     * the call reverted with no returned reason, this function reverts with a
     * {FailedInnerCall} error.
     *
     * 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.
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0);
    }
    /**
     * @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`.
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        if (address(this).balance < value) {
            revert AddressInsufficientBalance(address(this));
        }
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, success, returndata);
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, success, returndata);
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata);
    }
    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and reverts if the target
     * was not a contract or bubbling up the revert reason (falling back to {FailedInnerCall}) in case of an
     * unsuccessful call.
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata
    ) internal view returns (bytes memory) {
        if (!success) {
            _revert(returndata);
        } else {
            // only check if target is a contract if the call was successful and the return data is empty
            // otherwise we already know that it was a contract
            if (returndata.length == 0 && target.code.length == 0) {
                revert AddressEmptyCode(target);
            }
            return returndata;
        }
    }
    /**
     * @dev Tool to verify that a low level call was successful, and reverts if it wasn't, either by bubbling the
     * revert reason or with a default {FailedInnerCall} error.
     */
    function verifyCallResult(bool success, bytes memory returndata) internal pure returns (bytes memory) {
        if (!success) {
            _revert(returndata);
        } else {
            return returndata;
        }
    }
    /**
     * @dev Reverts with returndata if present. Otherwise reverts with {FailedInnerCall}.
     */
    function _revert(bytes memory returndata) 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 FailedInnerCall();
        }
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.1) (utils/Context.sol)
pragma solidity ^0.8.20;
/**
 * @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;
    }
    function _contextSuffixLength() internal view virtual returns (uint256) {
        return 0;
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/IERC20.sol)
pragma solidity ^0.8.20;
/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);
    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
    /**
     * @dev Returns the value of tokens in existence.
     */
    function totalSupply() external view returns (uint256);
    /**
     * @dev Returns the value of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);
    /**
     * @dev Moves a `value` amount of tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 value) 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 a `value` amount of tokens 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 value) external returns (bool);
    /**
     * @dev Moves a `value` amount of tokens from `from` to `to` using the
     * allowance mechanism. `value` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address from, address to, uint256 value) external returns (bool);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/extensions/IERC20Permit.sol)
pragma solidity ^0.8.20;
/**
 * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
 * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
 *
 * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
 * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
 * need to send a transaction, and thus is not required to hold Ether at all.
 *
 * ==== Security Considerations
 *
 * There are two important considerations concerning the use of `permit`. The first is that a valid permit signature
 * expresses an allowance, and it should not be assumed to convey additional meaning. In particular, it should not be
 * considered as an intention to spend the allowance in any specific way. The second is that because permits have
 * built-in replay protection and can be submitted by anyone, they can be frontrun. A protocol that uses permits should
 * take this into consideration and allow a `permit` call to fail. Combining these two aspects, a pattern that may be
 * generally recommended is:
 *
 * ```solidity
 * function doThingWithPermit(..., uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s) public {
 *     try token.permit(msg.sender, address(this), value, deadline, v, r, s) {} catch {}
 *     doThing(..., value);
 * }
 *
 * function doThing(..., uint256 value) public {
 *     token.safeTransferFrom(msg.sender, address(this), value);
 *     ...
 * }
 * ```
 *
 * Observe that: 1) `msg.sender` is used as the owner, leaving no ambiguity as to the signer intent, and 2) the use of
 * `try/catch` allows the permit to fail and makes the code tolerant to frontrunning. (See also
 * {SafeERC20-safeTransferFrom}).
 *
 * Additionally, note that smart contract wallets (such as Argent or Safe) are not able to produce permit signatures, so
 * contracts should have entry points that don't rely on permit.
 */
interface IERC20Permit {
    /**
     * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
     * given ``owner``'s signed approval.
     *
     * IMPORTANT: The same issues {IERC20-approve} has related to transaction
     * ordering also apply here.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `deadline` must be a timestamp in the future.
     * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
     * over the EIP712-formatted function arguments.
     * - the signature must use ``owner``'s current nonce (see {nonces}).
     *
     * For more information on the signature format, see the
     * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
     * section].
     *
     * CAUTION: See Security Considerations above.
     */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;
    /**
     * @dev Returns the current nonce for `owner`. This value must be
     * included whenever a signature is generated for {permit}.
     *
     * Every successful call to {permit} increases ``owner``'s nonce by one. This
     * prevents a signature from being used multiple times.
     */
    function nonces(address owner) external view returns (uint256);
    /**
     * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
     */
    // solhint-disable-next-line func-name-mixedcase
    function DOMAIN_SEPARATOR() external view returns (bytes32);
}