// SPDX-License-Identifier: MIT
pragma solidity ^0.8.12;


/// The messenger interface.
///
/// Implementations of this interface are expected to transport
/// messages across the L1 <-> L2 boundary. For instance,
/// if an implementation is deployed on L1, the :sol:func:`sendMessage`
/// would send a message to a L2 chain, as determined by the implementation.
/// In order to do this, a messenger implementation may use a native
/// messenger contract. In such cases, :sol:func:`nativeMessenger` must
/// return the address of the native messenger contract.
interface IMessenger {
    /// Send a message across the L1 <-> L2 boundary.
    ///
    /// @param target The message recipient.
    /// @param message The message.
    function sendMessage(address target, bytes calldata message) external;

    /// Return whether the call is allowed or not.
    ///
    /// @param caller The caller.
    /// @param courier The contract that is trying to deliver the message.
    function callAllowed(address caller, address courier)
    external
    view
    returns (bool);
}


/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
    enum Rounding {
        Down, // Toward negative infinity
        Up, // Toward infinity
        Zero // Toward zero
    }

    /**
     * @dev Returns the largest of two numbers.
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a > b ? a : b;
    }

    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow.
        return (a & b) + (a ^ b) / 2;
    }

    /**
     * @dev Returns the ceiling of the division of two numbers.
     *
     * This differs from standard division with `/` in that it rounds up instead
     * of rounding down.
     */
    function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b - 1) / b can overflow on addition, so we distribute.
        return a == 0 ? 0 : (a - 1) / b + 1;
    }

    /**
     * @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
     * @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv)
     * with further edits by Uniswap Labs also under MIT license.
     */
    function mulDiv(
        uint256 x,
        uint256 y,
        uint256 denominator
    ) internal pure returns (uint256 result) {
    unchecked {
        // 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
        // use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
        // variables such that product = prod1 * 2^256 + prod0.
        uint256 prod0; // Least significant 256 bits of the product
        uint256 prod1; // Most significant 256 bits of the product
        assembly {
            let mm := mulmod(x, y, not(0))
            prod0 := mul(x, y)
            prod1 := sub(sub(mm, prod0), lt(mm, prod0))
        }

        // Handle non-overflow cases, 256 by 256 division.
        if (prod1 == 0) {
            return prod0 / denominator;
        }

        // Make sure the result is less than 2^256. Also prevents denominator == 0.
        require(denominator > prod1);

        ///////////////////////////////////////////////
        // 512 by 256 division.
        ///////////////////////////////////////////////

        // Make division exact by subtracting the remainder from [prod1 prod0].
        uint256 remainder;
        assembly {
        // Compute remainder using mulmod.
            remainder := mulmod(x, y, denominator)

        // Subtract 256 bit number from 512 bit number.
            prod1 := sub(prod1, gt(remainder, prod0))
            prod0 := sub(prod0, remainder)
        }

        // Factor powers of two out of denominator and compute largest power of two divisor of denominator. Always >= 1.
        // See https://cs.stackexchange.com/q/138556/92363.

        // Does not overflow because the denominator cannot be zero at this stage in the function.
        uint256 twos = denominator & (~denominator + 1);
        assembly {
        // Divide denominator by twos.
            denominator := div(denominator, twos)

        // Divide [prod1 prod0] by twos.
            prod0 := div(prod0, twos)

        // Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
            twos := add(div(sub(0, twos), twos), 1)
        }

        // Shift in bits from prod1 into prod0.
        prod0 |= prod1 * twos;

        // Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such
        // that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for
        // four bits. That is, denominator * inv = 1 mod 2^4.
        uint256 inverse = (3 * denominator) ^ 2;

        // Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also works
        // in modular arithmetic, doubling the correct bits in each step.
        inverse *= 2 - denominator * inverse; // inverse mod 2^8
        inverse *= 2 - denominator * inverse; // inverse mod 2^16
        inverse *= 2 - denominator * inverse; // inverse mod 2^32
        inverse *= 2 - denominator * inverse; // inverse mod 2^64
        inverse *= 2 - denominator * inverse; // inverse mod 2^128
        inverse *= 2 - denominator * inverse; // inverse mod 2^256

        // Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
        // This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is
        // less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1
        // is no longer required.
        result = prod0 * inverse;
        return result;
    }
    }

    /**
     * @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
     */
    function mulDiv(
        uint256 x,
        uint256 y,
        uint256 denominator,
        Rounding rounding
    ) internal pure returns (uint256) {
        uint256 result = mulDiv(x, y, denominator);
        if (rounding == Rounding.Up && mulmod(x, y, denominator) > 0) {
            result += 1;
        }
        return result;
    }

    /**
     * @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded down.
     *
     * Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
     */
    function sqrt(uint256 a) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }

        // For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.
        //
        // We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have
        // `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.
        //
        // This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`
        // → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`
        // → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`
        //
        // Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.
        uint256 result = 1 << (log2(a) >> 1);

        // At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,
        // since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at
        // every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision
        // into the expected uint128 result.
    unchecked {
        result = (result + a / result) >> 1;
        result = (result + a / result) >> 1;
        result = (result + a / result) >> 1;
        result = (result + a / result) >> 1;
        result = (result + a / result) >> 1;
        result = (result + a / result) >> 1;
        result = (result + a / result) >> 1;
        return min(result, a / result);
    }
    }

    /**
     * @notice Calculates sqrt(a), following the selected rounding direction.
     */
    function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
    unchecked {
        uint256 result = sqrt(a);
        return result + (rounding == Rounding.Up && result * result < a ? 1 : 0);
    }
    }

    /**
     * @dev Return the log in base 2, rounded down, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
    unchecked {
        if (value >> 128 > 0) {
            value >>= 128;
            result += 128;
        }
        if (value >> 64 > 0) {
            value >>= 64;
            result += 64;
        }
        if (value >> 32 > 0) {
            value >>= 32;
            result += 32;
        }
        if (value >> 16 > 0) {
            value >>= 16;
            result += 16;
        }
        if (value >> 8 > 0) {
            value >>= 8;
            result += 8;
        }
        if (value >> 4 > 0) {
            value >>= 4;
            result += 4;
        }
        if (value >> 2 > 0) {
            value >>= 2;
            result += 2;
        }
        if (value >> 1 > 0) {
            result += 1;
        }
    }
        return result;
    }

    /**
     * @dev Return the log in base 2, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {
    unchecked {
        uint256 result = log2(value);
        return result + (rounding == Rounding.Up && 1 << result < value ? 1 : 0);
    }
    }

    /**
     * @dev Return the log in base 10, rounded down, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
    unchecked {
        if (value >= 10**64) {
            value /= 10**64;
            result += 64;
        }
        if (value >= 10**32) {
            value /= 10**32;
            result += 32;
        }
        if (value >= 10**16) {
            value /= 10**16;
            result += 16;
        }
        if (value >= 10**8) {
            value /= 10**8;
            result += 8;
        }
        if (value >= 10**4) {
            value /= 10**4;
            result += 4;
        }
        if (value >= 10**2) {
            value /= 10**2;
            result += 2;
        }
        if (value >= 10**1) {
            result += 1;
        }
    }
        return result;
    }

    /**
     * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {
    unchecked {
        uint256 result = log10(value);
        return result + (rounding == Rounding.Up && 10**result < value ? 1 : 0);
    }
    }

    /**
     * @dev Return the log in base 256, rounded down, of a positive value.
     * Returns 0 if given 0.
     *
     * Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.
     */
    function log256(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
    unchecked {
        if (value >> 128 > 0) {
            value >>= 128;
            result += 16;
        }
        if (value >> 64 > 0) {
            value >>= 64;
            result += 8;
        }
        if (value >> 32 > 0) {
            value >>= 32;
            result += 4;
        }
        if (value >> 16 > 0) {
            value >>= 16;
            result += 2;
        }
        if (value >> 8 > 0) {
            result += 1;
        }
    }
        return result;
    }

    /**
     * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {
    unchecked {
        uint256 result = log256(value);
        return result + (rounding == Rounding.Up && 1 << (result * 8) < value ? 1 : 0);
    }
    }
}

/**
 * @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.
 */
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].
     */
    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);
}
/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);

    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `from` to `to` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) external returns (bool);
}


/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
interface IERC20Metadata is IERC20 {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the symbol of the token.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}

/**
 * @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;
    }
}

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.openzeppelin.com/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin Contracts guidelines: functions revert
 * instead returning `false` on failure. This behavior is nonetheless
 * conventional and does not conflict with the expectations of ERC20
 * applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20, IERC20Metadata {
    mapping(address => uint256) private _balances;

    mapping(address => mapping(address => uint256)) private _allowances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;

    /**
     * @dev Sets the values for {name} and {symbol}.
     *
     * The default value of {decimals} is 18. To select a different value for
     * {decimals} you should overload it.
     *
     * All two of these values are immutable: they can only be set once during
     * construction.
     */
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5.05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the value {ERC20} uses, unless this function is
     * overridden;
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view virtual override returns (uint8) {
        return 18;
    }

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view virtual override returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address to, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _transfer(owner, to, amount);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on
     * `transferFrom`. This is semantically equivalent to an infinite approval.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20}.
     *
     * NOTE: Does not update the allowance if the current allowance
     * is the maximum `uint256`.
     *
     * Requirements:
     *
     * - `from` and `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     * - the caller must have allowance for ``from``'s tokens of at least
     * `amount`.
     */
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) public virtual override returns (bool) {
        address spender = _msgSender();
        _spendAllowance(from, spender, amount);
        _transfer(from, to, amount);
        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, allowance(owner, spender) + addedValue);
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        address owner = _msgSender();
        uint256 currentAllowance = allowance(owner, spender);
        require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
    unchecked {
        _approve(owner, spender, currentAllowance - subtractedValue);
    }

        return true;
    }

    /**
     * @dev Moves `amount` of tokens from `from` to `to`.
     *
     * This internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     */
    function _transfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(from, to, amount);

        uint256 fromBalance = _balances[from];
        require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
    unchecked {
        _balances[from] = fromBalance - amount;
        // Overflow not possible: the sum of all balances is capped by totalSupply, and the sum is preserved by
        // decrementing then incrementing.
        _balances[to] += amount;
    }

        emit Transfer(from, to, amount);

        _afterTokenTransfer(from, to, amount);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply += amount;
    unchecked {
        // Overflow not possible: balance + amount is at most totalSupply + amount, which is checked above.
        _balances[account] += amount;
    }
        emit Transfer(address(0), account, amount);

        _afterTokenTransfer(address(0), account, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
    unchecked {
        _balances[account] = accountBalance - amount;
        // Overflow not possible: amount <= accountBalance <= totalSupply.
        _totalSupply -= amount;
    }

        emit Transfer(account, address(0), amount);

        _afterTokenTransfer(account, address(0), amount);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
     *
     * This internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    /**
     * @dev Updates `owner` s allowance for `spender` based on spent `amount`.
     *
     * Does not update the allowance amount in case of infinite allowance.
     * Revert if not enough allowance is available.
     *
     * Might emit an {Approval} event.
     */
    function _spendAllowance(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        uint256 currentAllowance = allowance(owner, spender);
        if (currentAllowance != type(uint256).max) {
            require(currentAllowance >= amount, "ERC20: insufficient allowance");
        unchecked {
            _approve(owner, spender, currentAllowance - amount);
        }
        }
    }

    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}

    /**
     * @dev Hook that is called after any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * has been transferred to `to`.
     * - when `from` is zero, `amount` tokens have been minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens have been burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _afterTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}
}
/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant _SYMBOLS = "0123456789abcdef";
    uint8 private constant _ADDRESS_LENGTH = 20;

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
    unchecked {
        uint256 length = Math.log10(value) + 1;
        string memory buffer = new string(length);
        uint256 ptr;
        /// @solidity memory-safe-assembly
        assembly {
            ptr := add(buffer, add(32, length))
        }
        while (true) {
            ptr--;
            /// @solidity memory-safe-assembly
            assembly {
                mstore8(ptr, byte(mod(value, 10), _SYMBOLS))
            }
            value /= 10;
            if (value == 0) break;
        }
        return buffer;
    }
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
    unchecked {
        return toHexString(value, Math.log256(value) + 1);
    }
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = _SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }

    /**
     * @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal representation.
     */
    function toHexString(address addr) internal pure returns (string memory) {
        return toHexString(uint256(uint160(addr)), _ADDRESS_LENGTH);
    }
}


/**
 * @dev Elliptic Curve Digital Signature Algorithm (ECDSA) operations.
 *
 * These functions can be used to verify that a message was signed by the holder
 * of the private keys of a given address.
 */
library ECDSA {
    enum RecoverError {
        NoError,
        InvalidSignature,
        InvalidSignatureLength,
        InvalidSignatureS,
        InvalidSignatureV // Deprecated in v4.8
    }

    function _throwError(RecoverError error) private pure {
        if (error == RecoverError.NoError) {
            return; // no error: do nothing
        } else if (error == RecoverError.InvalidSignature) {
            revert("ECDSA: invalid signature");
        } else if (error == RecoverError.InvalidSignatureLength) {
            revert("ECDSA: invalid signature length");
        } else if (error == RecoverError.InvalidSignatureS) {
            revert("ECDSA: invalid signature 's' value");
        }
    }

    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature` or error string. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise
     * be too long), and then calling {toEthSignedMessageHash} on it.
     *
     * Documentation for signature generation:
     * - with https://web3js.readthedocs.io/en/v1.3.4/web3-eth-accounts.html#sign[Web3.js]
     * - with https://docs.ethers.io/v5/api/signer/#Signer-signMessage[ethers]
     *
     * _Available since v4.3._
     */
    function tryRecover(bytes32 hash, bytes memory signature) internal pure returns (address, RecoverError) {
        if (signature.length == 65) {
            bytes32 r;
            bytes32 s;
            uint8 v;
            // ecrecover takes the signature parameters, and the only way to get them
            // currently is to use assembly.
            /// @solidity memory-safe-assembly
            assembly {
                r := mload(add(signature, 0x20))
                s := mload(add(signature, 0x40))
                v := byte(0, mload(add(signature, 0x60)))
            }
            return tryRecover(hash, v, r, s);
        } else {
            return (address(0), RecoverError.InvalidSignatureLength);
        }
    }

    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature`. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise
     * be too long), and then calling {toEthSignedMessageHash} on it.
     */
    function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, signature);
        _throwError(error);
        return recovered;
    }

    /**
     * @dev Overload of {ECDSA-tryRecover} that receives the `r` and `vs` short-signature fields separately.
     *
     * See https://eips.ethereum.org/EIPS/eip-2098[EIP-2098 short signatures]
     *
     * _Available since v4.3._
     */
    function tryRecover(
        bytes32 hash,
        bytes32 r,
        bytes32 vs
    ) internal pure returns (address, RecoverError) {
        bytes32 s = vs & bytes32(0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff);
        uint8 v = uint8((uint256(vs) >> 255) + 27);
        return tryRecover(hash, v, r, s);
    }

    /**
     * @dev Overload of {ECDSA-recover} that receives the `r and `vs` short-signature fields separately.
     *
     * _Available since v4.2._
     */
    function recover(
        bytes32 hash,
        bytes32 r,
        bytes32 vs
    ) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, r, vs);
        _throwError(error);
        return recovered;
    }

    /**
     * @dev Overload of {ECDSA-tryRecover} that receives the `v`,
     * `r` and `s` signature fields separately.
     *
     * _Available since v4.3._
     */
    function tryRecover(
        bytes32 hash,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal pure returns (address, RecoverError) {
        // EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
        // unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
        // the valid range for s in (301): 0 < s < secp256k1n ÷ 2 + 1, and for v in (302): v ∈ {27, 28}. Most
        // signatures from current libraries generate a unique signature with an s-value in the lower half order.
        //
        // If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
        // with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
        // vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
        // these malleable signatures as well.
        if (uint256(s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {
            return (address(0), RecoverError.InvalidSignatureS);
        }

        // If the signature is valid (and not malleable), return the signer address
        address signer = ecrecover(hash, v, r, s);
        if (signer == address(0)) {
            return (address(0), RecoverError.InvalidSignature);
        }

        return (signer, RecoverError.NoError);
    }

    /**
     * @dev Overload of {ECDSA-recover} that receives the `v`,
     * `r` and `s` signature fields separately.
     */
    function recover(
        bytes32 hash,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, v, r, s);
        _throwError(error);
        return recovered;
    }

    /**
     * @dev Returns an Ethereum Signed Message, created from a `hash`. This
     * produces hash corresponding to the one signed with the
     * https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
     * JSON-RPC method as part of EIP-191.
     *
     * See {recover}.
     */
    function toEthSignedMessageHash(bytes32 hash) internal pure returns (bytes32) {
        // 32 is the length in bytes of hash,
        // enforced by the type signature above
        return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", hash));
    }

    /**
     * @dev Returns an Ethereum Signed Message, created from `s`. This
     * produces hash corresponding to the one signed with the
     * https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
     * JSON-RPC method as part of EIP-191.
     *
     * See {recover}.
     */
    function toEthSignedMessageHash(bytes memory s) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n", Strings.toString(s.length), s));
    }

    /**
     * @dev Returns an Ethereum Signed Typed Data, created from a
     * `domainSeparator` and a `structHash`. This produces hash corresponding
     * to the one signed with the
     * https://eips.ethereum.org/EIPS/eip-712[`eth_signTypedData`]
     * JSON-RPC method as part of EIP-712.
     *
     * See {recover}.
     */
    function toTypedDataHash(bytes32 domainSeparator, bytes32 structHash) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked("\x19\x01", domainSeparator, structHash));
    }
}

/**
 * @dev https://eips.ethereum.org/EIPS/eip-712[EIP 712] is a standard for hashing and signing of typed structured data.
 *
 * The encoding specified in the EIP is very generic, and such a generic implementation in Solidity is not feasible,
 * thus this contract does not implement the encoding itself. Protocols need to implement the type-specific encoding
 * they need in their contracts using a combination of `abi.encode` and `keccak256`.
 *
 * This contract implements the EIP 712 domain separator ({_domainSeparatorV4}) that is used as part of the encoding
 * scheme, and the final step of the encoding to obtain the message digest that is then signed via ECDSA
 * ({_hashTypedDataV4}).
 *
 * The implementation of the domain separator was designed to be as efficient as possible while still properly updating
 * the chain id to protect against replay attacks on an eventual fork of the chain.
 *
 * NOTE: This contract implements the version of the encoding known as "v4", as implemented by the JSON RPC method
 * https://docs.metamask.io/guide/signing-data.html[`eth_signTypedDataV4` in MetaMask].
 *
 * _Available since v3.4._
 */
abstract contract EIP712 {
    /* solhint-disable var-name-mixedcase */
    // Cache the domain separator as an immutable value, but also store the chain id that it corresponds to, in order to
    // invalidate the cached domain separator if the chain id changes.
    bytes32 private immutable _CACHED_DOMAIN_SEPARATOR;
    uint256 private immutable _CACHED_CHAIN_ID;
    address private immutable _CACHED_THIS;

    bytes32 private immutable _HASHED_NAME;
    bytes32 private immutable _HASHED_VERSION;
    bytes32 private immutable _TYPE_HASH;

    /* solhint-enable var-name-mixedcase */

    /**
     * @dev Initializes the domain separator and parameter caches.
     *
     * The meaning of `name` and `version` is specified in
     * https://eips.ethereum.org/EIPS/eip-712#definition-of-domainseparator[EIP 712]:
     *
     * - `name`: the user readable name of the signing domain, i.e. the name of the DApp or the protocol.
     * - `version`: the current major version of the signing domain.
     *
     * NOTE: These parameters cannot be changed except through a xref:learn::upgrading-smart-contracts.adoc[smart
     * contract upgrade].
     */
    constructor(string memory name, string memory version) {
        bytes32 hashedName = keccak256(bytes(name));
        bytes32 hashedVersion = keccak256(bytes(version));
        bytes32 typeHash = keccak256(
            "EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"
        );
        _HASHED_NAME = hashedName;
        _HASHED_VERSION = hashedVersion;
        _CACHED_CHAIN_ID = block.chainid;
        _CACHED_DOMAIN_SEPARATOR = _buildDomainSeparator(typeHash, hashedName, hashedVersion);
        _CACHED_THIS = address(this);
        _TYPE_HASH = typeHash;
    }

    /**
     * @dev Returns the domain separator for the current chain.
     */
    function _domainSeparatorV4() internal view returns (bytes32) {
        if (address(this) == _CACHED_THIS && block.chainid == _CACHED_CHAIN_ID) {
            return _CACHED_DOMAIN_SEPARATOR;
        } else {
            return _buildDomainSeparator(_TYPE_HASH, _HASHED_NAME, _HASHED_VERSION);
        }
    }

    function _buildDomainSeparator(
        bytes32 typeHash,
        bytes32 nameHash,
        bytes32 versionHash
    ) private view returns (bytes32) {
        return keccak256(abi.encode(typeHash, nameHash, versionHash, block.chainid, address(this)));
    }

    /**
     * @dev Given an already https://eips.ethereum.org/EIPS/eip-712#definition-of-hashstruct[hashed struct], this
     * function returns the hash of the fully encoded EIP712 message for this domain.
     *
     * This hash can be used together with {ECDSA-recover} to obtain the signer of a message. For example:
     *
     * ```solidity
     * bytes32 digest = _hashTypedDataV4(keccak256(abi.encode(
     *     keccak256("Mail(address to,string contents)"),
     *     mailTo,
     *     keccak256(bytes(mailContents))
     * )));
     * address signer = ECDSA.recover(digest, signature);
     * ```
     */
    function _hashTypedDataV4(bytes32 structHash) internal view virtual returns (bytes32) {
        return ECDSA.toTypedDataHash(_domainSeparatorV4(), structHash);
    }
}
/**
 * @title Counters
 * @author Matt Condon (@shrugs)
 * @dev Provides counters that can only be incremented, decremented or reset. This can be used e.g. to track the number
 * of elements in a mapping, issuing ERC721 ids, or counting request ids.
 *
 * Include with `using Counters for Counters.Counter;`
 */
library Counters {
    struct Counter {
        // This variable should never be directly accessed by users of the library: interactions must be restricted to
        // the library's function. As of Solidity v0.5.2, this cannot be enforced, though there is a proposal to add
        // this feature: see https://github.com/ethereum/solidity/issues/4637
        uint256 _value; // default: 0
    }

    function current(Counter storage counter) internal view returns (uint256) {
        return counter._value;
    }

    function increment(Counter storage counter) internal {
    unchecked {
        counter._value += 1;
    }
    }

    function decrement(Counter storage counter) internal {
        uint256 value = counter._value;
        require(value > 0, "Counter: decrement overflow");
    unchecked {
        counter._value = value - 1;
    }
    }

    function reset(Counter storage counter) internal {
        counter._value = 0;
    }
}

/**
 * @dev Implementation 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.
 *
 * _Available since v3.4._
 */
abstract contract ERC20Permit is ERC20, IERC20Permit, EIP712 {
    using Counters for Counters.Counter;

    mapping(address => Counters.Counter) private _nonces;

    // solhint-disable-next-line var-name-mixedcase
    bytes32 private constant _PERMIT_TYPEHASH =
    keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");
    /**
     * @dev In previous versions `_PERMIT_TYPEHASH` was declared as `immutable`.
     * However, to ensure consistency with the upgradeable transpiler, we will continue
     * to reserve a slot.
     * @custom:oz-renamed-from _PERMIT_TYPEHASH
     */
    // solhint-disable-next-line var-name-mixedcase
    bytes32 private _PERMIT_TYPEHASH_DEPRECATED_SLOT;

    /**
     * @dev Initializes the {EIP712} domain separator using the `name` parameter, and setting `version` to `"1"`.
     *
     * It's a good idea to use the same `name` that is defined as the ERC20 token name.
     */
    constructor(string memory name) EIP712(name, "1") {}

    /**
     * @dev See {IERC20Permit-permit}.
     */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) public virtual override {
        require(block.timestamp <= deadline, "ERC20Permit: expired deadline");

        bytes32 structHash = keccak256(abi.encode(_PERMIT_TYPEHASH, owner, spender, value, _useNonce(owner), deadline));

        bytes32 hash = _hashTypedDataV4(structHash);

        address signer = ECDSA.recover(hash, v, r, s);
        require(signer == owner, "ERC20Permit: invalid signature");

        _approve(owner, spender, value);
    }

    /**
     * @dev See {IERC20Permit-nonces}.
     */
    function nonces(address owner) public view virtual override returns (uint256) {
        return _nonces[owner].current();
    }

    /**
     * @dev See {IERC20Permit-DOMAIN_SEPARATOR}.
     */
    // solhint-disable-next-line func-name-mixedcase
    function DOMAIN_SEPARATOR() external view override returns (bytes32) {
        return _domainSeparatorV4();
    }

    /**
     * @dev "Consume a nonce": return the current value and increment.
     *
     * _Available since v4.1._
     */
    function _useNonce(address owner) internal virtual returns (uint256 current) {
        Counters.Counter storage nonce = _nonces[owner];
        current = nonce.current();
        nonce.increment();
    }
}



/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
     * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
     *
     * _Available since v4.8._
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                // only check isContract if the call was successful and the return data is empty
                // otherwise we already know that it was a contract
                require(isContract(target), "Address: call to non-contract");
            }
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    /**
     * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason or using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    function _revert(bytes memory returndata, string memory errorMessage) private pure {
        // Look for revert reason and bubble it up if present
        if (returndata.length > 0) {
            // The easiest way to bubble the revert reason is using memory via assembly
            /// @solidity memory-safe-assembly
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert(errorMessage);
        }
    }
}
/**
 * @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;

    function safeTransfer(
        IERC20 token,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(
        IERC20 token,
        address from,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender) + value;
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
    unchecked {
        uint256 oldAllowance = token.allowance(address(this), spender);
        require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
        uint256 newAllowance = oldAllowance - value;
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }
    }

    function safePermit(
        IERC20Permit token,
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal {
        uint256 nonceBefore = token.nonces(owner);
        token.permit(owner, spender, value, deadline, v, r, s);
        uint256 nonceAfter = token.nonces(owner);
        require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
    }

    /**
     * @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, "SafeERC20: low-level call failed");
        if (returndata.length > 0) {
            // Return data is optional
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}



library BeamerUtils {
    function createRequestId(
        uint256 sourceChainId,
        uint256 targetChainId,
        address targetTokenAddress,
        address targetReceiverAddress,
        uint256 amount,
        uint96 nonce
    ) internal pure returns (bytes32) {
        return
        keccak256(
            abi.encodePacked(
                sourceChainId,
                targetChainId,
                targetTokenAddress,
                targetReceiverAddress,
                amount,
                nonce
            )
        );
    }
}


/**
 * @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());
    }
}

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}



/// A helper contract that provides a way to restrict callers of restricted functions
/// to a single address. This allows for a trusted call chain,
/// as described in :ref:`contracts' architecture <contracts-architecture>`.
contract RestrictedCalls is Ownable {
    /// Maps caller chain IDs to tuples [caller, messenger].
    ///
    /// For same-chain calls, the messenger address is 0x0.
    mapping(uint256 => address[2]) public callers;

    function _addCaller(
        uint256 callerChainId,
        address caller,
        address messenger
    ) internal {
        require(caller != address(0), "RestrictedCalls: caller cannot be 0");
        require(
            callers[callerChainId][0] == address(0),
            "RestrictedCalls: caller already exists"
        );
        callers[callerChainId] = [caller, messenger];
    }

    /// Allow calls from an address on the same chain.
    ///
    /// @param caller The caller.
    function addCaller(address caller) external onlyOwner {
        _addCaller(block.chainid, caller, address(0));
    }

    /// Allow calls from an address on another chain.
    ///
    /// @param callerChainId The caller's chain ID.
    /// @param caller The caller.
    /// @param messenger The messenger.
    function addCaller(
        uint256 callerChainId,
        address caller,
        address messenger
    ) external onlyOwner {
        _addCaller(callerChainId, caller, messenger);
    }

    /// Mark the function as restricted.
    ///
    /// Calls to the restricted function can only come from an address that
    /// was previously added by a call to :sol:func:`addCaller`.
    ///
    /// Example usage::
    ///
    ///     restricted(block.chainid)   // expecting calls from the same chain
    ///     restricted(otherChainId)    // expecting calls from another chain
    ///
    modifier restricted(uint256 callerChainId) {
        address caller = callers[callerChainId][0];

        if (callerChainId == block.chainid) {
            require(msg.sender == caller, "RestrictedCalls: call disallowed");
        } else {
            address messenger = callers[callerChainId][1];
            require(
                messenger != address(0),
                "RestrictedCalls: messenger not set"
            );
            require(
                IMessenger(messenger).callAllowed(caller, msg.sender),
                "RestrictedCalls: call disallowed"
            );
        }
        _;
    }
}



/// Liquidity Provider Whitelist.
///
/// This contract describes the concept of a whitelist for allowed Lps. RequestManager and FillManager
/// inherit from this contract.
contract LpWhitelist is Ownable {
    /// Emitted when a liquidity provider has been added to the set of allowed
    /// liquidity providers.
    ///
    /// .. seealso:: :sol:func:`addAllowedLp`
    event LpAdded(address lp);

    /// Emitted when a liquidity provider has been removed from the set of allowed
    /// liquidity providers.
    ///
    /// .. seealso:: :sol:func:`removeAllowedLp`
    event LpRemoved(address lp);

    /// The mapping indicating whether liquidity providers have allowance or not
    mapping(address => bool) public allowedLps;

    /// Modifier to check whether the passed address is an allowed LP
    modifier onlyAllowed(address addressToCheck) {
        require(allowedLps[addressToCheck], "Not allowed");
        _;
    }

    /// Add a liquidity provider to the set of allowed liquidity providers.
    ///
    /// .. note:: This function can only be called by the contract owner.
    ///
    /// @param newLp The liquidity provider.
    function addAllowedLp(address newLp) public onlyOwner {
        allowedLps[newLp] = true;

        emit LpAdded(newLp);
    }

    /// Remove a liquidity provider from the set of allowed liquidity providers.
    ///
    /// .. note:: This function can only be called by the contract owner.
    ///
    /// @param oldLp The liquidity provider.
    function removeAllowedLp(address oldLp) public onlyOwner {
        delete allowedLps[oldLp];

        emit LpRemoved(oldLp);
    }
}


/// The request manager.
///
/// This contract is responsible for keeping track of transfer requests,
/// implementing the rules of the challenge game and holding deposited
/// tokens until they are withdrawn.
/// The information passed by L1 resolution will be stored with the respective requests.
///
/// It is the only contract that agents need to interact with on the source chain.
/// .. note::
///
///   The functions resolveRequest and invalidateFill can only be called by
///   the :sol:contract:`Resolver` contract, via a chain-dependent messenger contract.
contract RequestManager is Ownable, LpWhitelist, RestrictedCalls, Pausable {
    using Math for uint256;
    using SafeERC20 for IERC20;

    // Structs
    // TODO: check if we can use a smaller type for `targetChainId`, so that the
    // fields can be packed into one storage slot
    struct Request {
        address sender;
        address sourceTokenAddress;
        uint256 targetChainId;
        uint256 amount;
        uint32 validUntil;
        uint96 lpFee;
        uint96 protocolFee;
        uint32 activeClaims;
        uint96 withdrawClaimId;
        address filler;
        bytes32 fillId;
        mapping(bytes32 => bool) invalidFillIds;
    }

    struct Claim {
        bytes32 requestId;
        address claimer;
        uint96 claimerStake;
        mapping(address => uint96) challengersStakes;
        address lastChallenger;
        uint96 challengerStakeTotal;
        uint256 withdrawnAmount;
        uint256 termination;
        bytes32 fillId;
    }

    struct Token {
        uint256 transferLimit;
        uint96 minLpFee;
        uint32 lpFeePPM;
        uint32 protocolFeePPM;
        uint96 collectedProtocolFees;
    }

    // Events

    /// Emitted when a new request has been created.
    ///
    /// .. seealso:: :sol:func:`createRequest`
    event RequestCreated(
        bytes32 indexed requestId,
        uint256 targetChainId,
        address sourceTokenAddress,
        address targetTokenAddress,
        address indexed sourceAddress,
        address targetAddress,
        uint256 amount,
        uint96 nonce,
        uint32 validUntil
    );

    /// Emitted when the token deposit for request ``requestId`` has been
    /// transferred to the ``receiver``.
    ///
    /// This can happen in two cases:
    ///
    ///  * the request expired and the request submitter called :sol:func:`withdrawExpiredRequest`
    ///  * a claim related to the request has been resolved successfully in favor of the claimer
    ///
    /// .. seealso:: :sol:func:`withdraw` :sol:func:`withdrawExpiredRequest`
    event DepositWithdrawn(bytes32 requestId, address receiver);

    /// Emitted when a claim or a counter-claim (challenge) has been made.
    ///
    /// .. seealso:: :sol:func:`claimRequest` :sol:func:`challengeClaim`
    event ClaimMade(
        bytes32 indexed requestId,
        uint96 claimId,
        address claimer,
        uint96 claimerStake,
        address lastChallenger,
        uint96 challengerStakeTotal,
        uint256 termination,
        bytes32 fillId
    );

    /// Emitted when staked native tokens tied to a claim have been withdrawn.
    ///
    /// This can only happen when the claim has been resolved and the caller
    /// of :sol:func:`withdraw` is allowed to withdraw their stake.
    ///
    /// .. seealso:: :sol:func:`withdraw`
    event ClaimStakeWithdrawn(
        uint96 claimId,
        bytes32 indexed requestId,
        address stakeRecipient
    );

    event FinalityPeriodUpdated(uint256 targetChainId, uint256 finalityPeriod);

    /// Emitted when token object of a token address is updated.
    ///
    /// .. seealso:: :sol:func:`updateToken`
    event TokenUpdated(
        address tokenAddress,
        uint256 transferLimit,
        uint96 minLpFee,
        uint32 lpFeePPM,
        uint32 protocolFeePPM
    );

    /// Emitted when a request has been resolved via L1 resolution.
    ///
    /// .. seealso:: :sol:func:`resolveRequest`
    event RequestResolved(bytes32 requestId, address filler, bytes32 fillId);

    /// Emitted when an invalidated fill has been resolved.
    ///
    /// .. seealso:: :sol:func:`invalidateFill`
    event FillInvalidatedResolved(bytes32 requestId, bytes32 fillId);

    // Constants

    /// The minimum amount of source chain's native token that the claimer needs to
    /// provide when making a claim, as well in each round of the challenge game.
    uint96 public immutable claimStake;

    /// The additional time given to claim a request. This value is added to the
    /// validity period of a request.
    uint256 public immutable claimRequestExtension;

    /// The period for which the claim is valid.
    uint256 public immutable claimPeriod;

    /// The period by which the termination time of a claim is extended after each
    /// round of the challenge game. This period should allow enough time for the
    /// other parties to counter-challenge.
    ///
    /// .. note::
    ///
    ///    The claim's termination time is extended only if it is less than the
    ///    extension time.
    ///
    /// Note that in the first challenge round, i.e. the round initiated by the first
    /// challenger, the termination time is extended additionally by the finality
    /// period of the target chain. This is done to allow for L1 resolution.
    uint256 public immutable challengePeriodExtension;

    /// The minimum validity period of a request.
    uint256 public constant MIN_VALIDITY_PERIOD = 30 minutes;

    /// The maximum validity period of a request.
    uint256 public constant MAX_VALIDITY_PERIOD = 48 hours;

    /// withdrawClaimId is set to this value when an expired request gets withdrawn by the sender
    uint96 public constant CLAIM_ID_WITHDRAWN_EXPIRED = type(uint96).max;

    // Variables

    /// A counter used to generate request and claim IDs.
    /// The variable holds the most recently used nonce and must
    /// be incremented to get the next nonce
    uint96 public currentNonce;

    /// Maps target rollup chain IDs to finality periods.
    /// Finality periods are in seconds.
    mapping(uint256 => uint256) public finalityPeriods;

    /// Maps request IDs to requests.
    mapping(bytes32 => Request) public requests;

    /// Maps claim IDs to claims.
    mapping(uint96 => Claim) public claims;

    /// Maps ERC20 token address to tokens
    mapping(address => Token) public tokens;

    /// Compute the liquidity provider fee that needs to be paid for a given transfer amount.
    function lpFee(address tokenAddress, uint256 amount)
    public
    view
    returns (uint256)
    {
        Token storage token = tokens[tokenAddress];
        return Math.max(token.minLpFee, (amount * token.lpFeePPM) / 1_000_000);
    }

    /// Compute the protocol fee that needs to be paid for a given transfer amount.
    function protocolFee(address tokenAddress, uint256 amount)
    public
    view
    returns (uint256)
    {
        return (amount * tokens[tokenAddress].protocolFeePPM) / 1_000_000;
    }

    /// Compute the total fee that needs to be paid for a given transfer amount.
    /// The total fee is the sum of the liquidity provider fee and the protocol fee.
    function totalFee(address tokenAddress, uint256 amount)
    public
    view
    returns (uint256)
    {
        return lpFee(tokenAddress, amount) + protocolFee(tokenAddress, amount);
    }

    // Modifiers

    /// Check whether a given request ID is valid.
    modifier validRequestId(bytes32 requestId) {
        require(
            requests[requestId].sender != address(0),
            "requestId not valid"
        );
        _;
    }

    /// Check whether a given claim ID is valid.
    modifier validClaimId(uint96 claimId) {
        require(claims[claimId].claimer != address(0), "claimId not valid");
        _;
    }

    /// Constructor.
    ///
    /// @param _claimStake Claim stake amount.
    /// @param _claimRequestExtension Extension to claim a request after validity period ends.
    /// @param _claimPeriod Claim period, in seconds.
    /// @param _challengePeriodExtension Challenge period extension, in seconds.
    constructor(
        uint96 _claimStake,
        uint256 _claimRequestExtension,
        uint256 _claimPeriod,
        uint256 _challengePeriodExtension
    ) {
        claimStake = _claimStake;
        claimRequestExtension = _claimRequestExtension;
        claimPeriod = _claimPeriod;
        challengePeriodExtension = _challengePeriodExtension;
    }

    /// Create a new transfer request.
    ///
    /// @param targetChainId ID of the target chain.
    /// @param sourceTokenAddress Address of the token contract on the source chain.
    /// @param targetTokenAddress Address of the token contract on the target chain.
    /// @param targetAddress Recipient address on the target chain.
    /// @param amount Amount of tokens to transfer. Does not include fees.
    /// @param validityPeriod The number of seconds the request is to be considered valid.
    ///                       Once its validity period has elapsed, the request cannot be claimed
    ///                       anymore and will eventually expire, allowing the request submitter
    ///                       to withdraw the deposited tokens if there are no active claims.
    /// @return ID of the newly created request.
    function createRequest(
        uint256 targetChainId,
        address sourceTokenAddress,
        address targetTokenAddress,
        address targetAddress,
        uint256 amount,
        uint256 validityPeriod
    ) external whenNotPaused returns (bytes32) {
        require(
            finalityPeriods[targetChainId] != 0,
            "Target rollup not supported"
        );
        require(
            validityPeriod >= MIN_VALIDITY_PERIOD,
            "Validity period too short"
        );
        require(
            validityPeriod <= MAX_VALIDITY_PERIOD,
            "Validity period too long"
        );
        require(
            amount <= tokens[sourceTokenAddress].transferLimit,
            "Amount exceeds transfer limit"
        );

        uint256 lpFeeTokenAmount = lpFee(sourceTokenAddress, amount);
        uint256 protocolFeeTokenAmount = protocolFee(
            sourceTokenAddress,
            amount
        );

        require(
            IERC20(sourceTokenAddress).allowance(msg.sender, address(this)) >=
            amount + lpFeeTokenAmount + protocolFeeTokenAmount,
            "Insufficient allowance"
        );

        uint96 nonce = currentNonce + 1;
        currentNonce = nonce;

        bytes32 requestId = BeamerUtils.createRequestId(
            block.chainid,
            targetChainId,
            targetTokenAddress,
            targetAddress,
            amount,
            nonce
        );

        Request storage newRequest = requests[requestId];
        newRequest.sender = msg.sender;
        newRequest.sourceTokenAddress = sourceTokenAddress;
        newRequest.targetChainId = targetChainId;
        newRequest.amount = amount;
        newRequest.validUntil = uint32(block.timestamp + validityPeriod);
        newRequest.lpFee = uint96(lpFeeTokenAmount);
        newRequest.protocolFee = uint96(protocolFeeTokenAmount);

        emit RequestCreated(
            requestId,
            targetChainId,
            sourceTokenAddress,
            targetTokenAddress,
            msg.sender,
            targetAddress,
            amount,
            nonce,
            uint32(block.timestamp + validityPeriod)
        );

        IERC20(sourceTokenAddress).safeTransferFrom(
            msg.sender,
            address(this),
            amount + lpFeeTokenAmount + protocolFeeTokenAmount
        );

        return requestId;
    }

    /// Withdraw funds deposited with an expired request.
    ///
    /// No claims must be active for the request.
    ///
    /// @param requestId ID of the expired request.
    function withdrawExpiredRequest(bytes32 requestId)
    external
    validRequestId(requestId)
    {
        Request storage request = requests[requestId];

        require(request.withdrawClaimId == 0, "Deposit already withdrawn");
        require(
            block.timestamp >= request.validUntil,
            "Request not expired yet"
        );
        require(request.activeClaims == 0, "Active claims running");

        request.withdrawClaimId = CLAIM_ID_WITHDRAWN_EXPIRED;

        emit DepositWithdrawn(requestId, request.sender);

        IERC20 token = IERC20(request.sourceTokenAddress);
        token.safeTransfer(
            request.sender,
            request.amount + request.lpFee + request.protocolFee
        );
    }

    /// Claim that a request was filled by the caller.
    ///
    /// The request must still be valid at call time.
    /// The caller must provide the ``claimStake`` amount of source rollup's native
    /// token.
    ///
    /// @param requestId ID of the request.
    /// @param fillId The fill ID.
    /// @return The claim ID.
    function claimRequest(bytes32 requestId, bytes32 fillId)
    external
    payable
    validRequestId(requestId)
    onlyAllowed(msg.sender)
    returns (uint96)
    {
        return claimRequest(msg.sender, requestId, fillId);
    }

    /// Claim that a request was filled.
    ///
    /// The request must still be valid at call time.
    /// The caller must provide the ``claimStake`` amount of source rollup's native
    /// token.
    /// Only the claimer may get the stake back later.
    ///
    /// @param claimer Address of the claimer.
    /// @param requestId ID of the request.
    /// @param fillId The fill ID.
    /// @return The claim ID.
    function claimRequest(
        address claimer,
        bytes32 requestId,
        bytes32 fillId
    )
    public
    payable
    validRequestId(requestId)
    onlyAllowed(claimer)
    returns (uint96)
    {
        Request storage request = requests[requestId];

        require(
            block.timestamp < request.validUntil + claimRequestExtension,
            "Request cannot be claimed anymore"
        );
        require(request.withdrawClaimId == 0, "Deposit already withdrawn");
        require(msg.value == claimStake, "Invalid stake amount");
        require(fillId != bytes32(0), "FillId must not be 0x0");

        request.activeClaims += 1;

        uint96 nonce = currentNonce + 1;
        currentNonce = nonce;
        uint256 termination = block.timestamp + claimPeriod;

        Claim storage claim = claims[nonce];
        claim.requestId = requestId;
        claim.claimer = claimer;
        claim.claimerStake = uint96(msg.value);
        claim.termination = termination;
        claim.fillId = fillId;

        emit ClaimMade(
            requestId,
            nonce,
            claimer,
            uint96(msg.value),
            address(0),
            0,
            termination,
            fillId
        );

        return nonce;
    }

    /// Challenge an existing claim.
    ///
    /// The claim must still be valid at call time.
    /// This function implements one round of the challenge game.
    /// The original claimer is allowed to call this function only
    /// after someone else made a challenge, i.e. every second round.
    /// However, once the original claimer counter-challenges, anyone
    /// can join the game and make another challenge.
    ///
    /// The caller must provide enough native tokens as their stake.
    /// For the original claimer, the minimum stake is
    /// ``challengerStakeTotal - claimerStake + claimStake``.
    ///
    /// For challengers, the minimum stake is
    /// ``claimerStake - challengerStakeTotal + 1``.
    ///
    /// An example (time flows downwards, claimStake = 10)::
    ///
    ///   claimRequest() by Max [stakes 10]
    ///   challengeClaim() by Alice [stakes 11]
    ///   challengeClaim() by Max [stakes 11]
    ///   challengeClaim() by Bob [stakes 16]
    ///
    /// In this example, if Max didn't want to lose the challenge game to
    /// Alice and Bob, he would have to challenge with a stake of at least 16.
    ///
    /// @param claimId The claim ID.
    function challengeClaim(uint96 claimId)
    external
    payable
    validClaimId(claimId)
    {
        Claim storage claim = claims[claimId];
        bytes32 requestId = claim.requestId;
        uint256 termination = claim.termination;
        require(block.timestamp < termination, "Claim expired");
        require(
            requests[requestId].filler == address(0),
            "Request already resolved"
        );
        require(
            !requests[requestId].invalidFillIds[claim.fillId],
            "Fill already invalidated"
        );

        uint256 periodExtension = challengePeriodExtension;
        address claimer = claim.claimer;
        uint96 claimerStake = claim.claimerStake;
        uint96 challengerStakeTotal = claim.challengerStakeTotal;

        if (claimerStake > challengerStakeTotal) {
            if (challengerStakeTotal == 0) {
                periodExtension += finalityPeriods[
                requests[requestId].targetChainId
                ];
            }
            require(msg.sender != claimer, "Cannot challenge own claim");
            require(
                msg.value >= claimerStake - challengerStakeTotal + 1,
                "Not enough stake provided"
            );
        } else {
            require(msg.sender == claimer, "Not eligible to outbid");
            require(
                msg.value >= challengerStakeTotal - claimerStake + claimStake,
                "Not enough stake provided"
            );
        }

        if (msg.sender == claimer) {
            claimerStake += uint96(msg.value);
            claim.claimerStake = claimerStake;
        } else {
            claim.lastChallenger = msg.sender;
            claim.challengersStakes[msg.sender] += uint96(msg.value);
            challengerStakeTotal += uint96(msg.value);
            claim.challengerStakeTotal = challengerStakeTotal;
        }

        if (block.timestamp + periodExtension > termination) {
            termination = block.timestamp + periodExtension;
            claim.termination = termination;
        }

        emit ClaimMade(
            requestId,
            claimId,
            claimer,
            claimerStake,
            claim.lastChallenger,
            challengerStakeTotal,
            termination,
            claim.fillId
        );
    }

    /// Withdraw the deposit that the request submitter left with the contract,
    /// as well as the staked native tokens associated with the claim.
    ///
    /// In case the caller of this function is a challenger that won the game,
    /// they will only get their staked native tokens plus the reward in the form
    /// of full (sole challenger) or partial (multiple challengers) amount
    /// of native tokens staked by the dishonest claimer.
    ///
    /// @param claimId The claim ID.
    /// @return The claim stakes receiver.
    function withdraw(uint96 claimId)
    external
    validClaimId(claimId)
    returns (address)
    {
        return withdraw(msg.sender, claimId);
    }

    /// Withdraw the deposit that the request submitter left with the contract,
    /// as well as the staked native tokens associated with the claim.
    ///
    /// This function is called on behalf of a participant. Only a participant
    /// may receive the funds if he is the winner of the challenge or the claim is valid.
    ///
    /// In case the caller of this function is a challenger that won the game,
    /// they will only get their staked native tokens plus the reward in the form
    /// of full (sole challenger) or partial (multiple challengers) amount
    /// of native tokens staked by the dishonest claimer.
    ///
    /// @param claimId The claim ID.
    /// @param participant The participant.
    /// @return The claim stakes receiver.
    function withdraw(address participant, uint96 claimId)
    public
    validClaimId(claimId)
    returns (address)
    {
        Claim storage claim = claims[claimId];
        address claimer = claim.claimer;
        require(
            participant == claimer || claim.challengersStakes[participant] > 0,
            "Not an active participant in this claim"
        );
        bytes32 requestId = claim.requestId;
        Request storage request = requests[requestId];

        (address stakeRecipient, uint256 ethToTransfer) = resolveClaim(
            participant,
            claimId
        );

        if (claim.challengersStakes[stakeRecipient] > 0) {
            //Re-entrancy protection
            claim.challengersStakes[stakeRecipient] = 0;
        }

        uint256 withdrawnAmount = claim.withdrawnAmount;

        // First time withdraw is called, remove it from active claims
        if (withdrawnAmount == 0) {
            request.activeClaims -= 1;
        }
        withdrawnAmount += ethToTransfer;
        claim.withdrawnAmount = withdrawnAmount;

        require(
            withdrawnAmount <= claim.claimerStake + claim.challengerStakeTotal,
            "Amount to withdraw too large"
        );

        (bool sent, ) = stakeRecipient.call{value: ethToTransfer}("");
        require(sent, "Failed to send Ether");

        emit ClaimStakeWithdrawn(claimId, requestId, stakeRecipient);

        if (request.withdrawClaimId == 0 && stakeRecipient == claimer) {
            withdrawDeposit(request, claimId);
        }

        return stakeRecipient;
    }

    function resolveClaim(address participant, uint96 claimId)
    private
    view
    returns (address, uint256)
    {
        Claim storage claim = claims[claimId];
        Request storage request = requests[claim.requestId];
        uint96 withdrawClaimId = request.withdrawClaimId;
        address claimer = claim.claimer;
        uint96 claimerStake = claim.claimerStake;
        uint96 challengerStakeTotal = claim.challengerStakeTotal;
        require(
            claim.withdrawnAmount < claimerStake + challengerStakeTotal,
            "Claim already withdrawn"
        );

        bool claimValid = false;

        // The claim is resolved with the following priority:
        // 1) The l1 resolved filler is the claimer and l1 resolved fillId matches, claim is valid
        // 2) FillId is true in request's invalidFillIds, claim is invalid
        // 3) The withdrawer's claim matches exactly this claim (same claimer address, same fillId)
        // 4) Claim properties, claim terminated and claimer has the highest stake
        address filler = request.filler;
        bytes32 fillId = request.fillId;

        if (filler != address(0)) {
            // Claim resolution via 1)
            claimValid = filler == claimer && fillId == claim.fillId;
        } else if (request.invalidFillIds[fillId]) {
            // Claim resolution via 2)
            claimValid = false;
        } else if (withdrawClaimId != 0) {
            // Claim resolution via 3)
            claimValid =
            claimer == claims[withdrawClaimId].claimer &&
            claim.fillId == claims[withdrawClaimId].fillId;
        } else {
            // Claim resolution via 4)
            require(
                block.timestamp >= claim.termination,
                "Claim period not finished"
            );
            claimValid = claimerStake > challengerStakeTotal;
        }

        // Calculate withdraw scheme for claim stakes
        uint96 ethToTransfer;
        address stakeRecipient;

        if (claimValid) {
            // If claim is valid, all stakes go to the claimer
            stakeRecipient = claimer;
            ethToTransfer = claimerStake + challengerStakeTotal;
        } else if (challengerStakeTotal > 0) {
            // If claim is invalid, partial withdrawal by the participant
            stakeRecipient = participant;
            ethToTransfer = 2 * claim.challengersStakes[stakeRecipient];
            require(ethToTransfer > 0, "Challenger has nothing to withdraw");
        } else {
            // The unlikely event is possible that a false claim has no challenger
            // If it is known that the claim is false then the claimer stake goes to the platform
            stakeRecipient = owner();
            ethToTransfer = claimerStake;
        }

        // If the challenger wins and is the last challenger, he gets either
        // twice his stake plus the excess stake (if the claimer was winning), or
        // twice his stake minus the difference between the claimer and challenger stakes (if the claimer was losing)
        if (stakeRecipient == claim.lastChallenger) {
            if (claimerStake > challengerStakeTotal) {
                ethToTransfer += (claimerStake - challengerStakeTotal);
            } else {
                ethToTransfer -= (challengerStakeTotal - claimerStake);
            }
        }

        return (stakeRecipient, ethToTransfer);
    }

    function withdrawDeposit(Request storage request, uint96 claimId) private {
        Claim storage claim = claims[claimId];
        address claimer = claim.claimer;
        emit DepositWithdrawn(claim.requestId, claimer);

        request.withdrawClaimId = claimId;

        tokens[request.sourceTokenAddress].collectedProtocolFees += request
        .protocolFee;

        IERC20 token = IERC20(request.sourceTokenAddress);
        token.safeTransfer(claimer, request.amount + request.lpFee);
    }

    /// Returns whether a request's deposit was withdrawn or not
    ///
    /// This can be true in two cases:
    /// 1. The deposit was withdrawn after the request was claimed and filled.
    /// 2. The submitter withdrew the deposit after the request's expiry.
    /// .. seealso:: :sol:func:`withdraw`
    /// .. seealso:: :sol:func:`withdrawExpiredRequest`
    ///
    /// @param requestId The request ID
    /// @return Whether the deposit corresponding to the given request ID was withdrawn
    function isWithdrawn(bytes32 requestId)
    public
    view
    validRequestId(requestId)
    returns (bool)
    {
        return requests[requestId].withdrawClaimId != 0;
    }

    /// Withdraw protocol fees collected by the contract.
    ///
    /// Protocol fees are paid in token transferred.
    ///
    /// .. note:: This function can only be called by the contract owner.
    ///
    /// @param tokenAddress The address of the token contract.
    /// @param recipient The address the fees should be sent to.
    function withdrawProtocolFees(address tokenAddress, address recipient)
    external
    onlyOwner
    {
        uint256 amount = tokens[tokenAddress].collectedProtocolFees;
        require(amount > 0, "Protocol fee is zero");
        tokens[tokenAddress].collectedProtocolFees = 0;

        IERC20 token = IERC20(tokenAddress);
        token.safeTransfer(recipient, amount);
    }

    function updateToken(
        address tokenAddress,
        uint256 transferLimit,
        uint96 minLpFee,
        uint32 lpFeePPM,
        uint32 protocolFeePPM
    ) external onlyOwner {
        require(lpFeePPM <= 999_999, "Maximum PPM of 999999 exceeded");
        require(protocolFeePPM <= 999_999, "Maximum PPM of 999999 exceeded");

        Token storage token = tokens[tokenAddress];
        token.transferLimit = transferLimit;
        token.minLpFee = minLpFee;
        token.lpFeePPM = lpFeePPM;
        token.protocolFeePPM = protocolFeePPM;

        emit TokenUpdated(
            tokenAddress,
            transferLimit,
            minLpFee,
            lpFeePPM,
            protocolFeePPM
        );
    }

    /// Set the finality period for the given target chain.
    ///
    /// .. note:: This function can only be called by the contract owner.
    ///
    /// @param targetChainId The target chain ID.
    /// @param finalityPeriod Finality period in seconds.
    function setFinalityPeriod(uint256 targetChainId, uint256 finalityPeriod)
    external
    onlyOwner
    {
        require(finalityPeriod > 0, "Finality period must be greater than 0");
        finalityPeriods[targetChainId] = finalityPeriod;

        emit FinalityPeriodUpdated(targetChainId, finalityPeriod);
    }

    /// Returns whether a fill is invalidated or not
    ///
    /// Calling invalidateFill() will set this boolean to true,
    /// marking that the ``fillId`` for the corresponding ``requestId`` was
    /// invalidated.
    /// Calling resolveRequest will validate it again, setting request.invalidatedFills[fillId]
    /// to false.
    /// .. seealso:: :sol:func:`invalidateFill`
    /// .. seealso:: :sol:func:`resolveRequest`
    ///
    /// @param requestId The request ID
    /// @param fillId The fill ID
    /// @return Whether the fill ID is invalid for the given request ID
    function isInvalidFill(bytes32 requestId, bytes32 fillId)
    public
    view
    returns (bool)
    {
        return requests[requestId].invalidFillIds[fillId];
    }

    /// Mark the request identified by ``requestId`` as filled by ``filler``.
    ///
    /// .. note::
    ///
    ///     This function is a restricted call function. Only callable by the added caller.
    ///
    /// @param requestId The request ID.
    /// @param fillId The fill ID.
    /// @param resolutionChainId The resolution (L1) chain ID.
    /// @param filler The address that filled the request.
    function resolveRequest(
        bytes32 requestId,
        bytes32 fillId,
        uint256 resolutionChainId,
        address filler
    ) external restricted(resolutionChainId) {
        Request storage request = requests[requestId];
        request.filler = filler;
        request.fillId = fillId;

        request.invalidFillIds[fillId] = false;

        emit RequestResolved(requestId, filler, fillId);
    }

    /// Mark the fill identified by ``requestId`` and ``fillId`` as invalid.
    ///
    /// .. note::
    ///
    ///     This function is a restricted call function. Only callable by the added caller.
    ///
    /// @param requestId The request ID.
    /// @param fillId The fill ID.
    /// @param resolutionChainId The resolution (L1) chain ID.
    function invalidateFill(
        bytes32 requestId,
        bytes32 fillId,
        uint256 resolutionChainId
    ) external restricted(resolutionChainId) {
        Request storage request = requests[requestId];
        require(
            request.filler == address(0),
            "Cannot invalidate resolved fills"
        );
        require(
            request.invalidFillIds[fillId] == false,
            "Fill already invalidated"
        );

        request.invalidFillIds[fillId] = true;

        emit FillInvalidatedResolved(requestId, fillId);
    }

    /// Pauses the contract.
    ///
    /// Once the contract is paused, it cannot be used to create new
    /// requests anymore. Withdrawing deposited funds and claim stakes
    /// still works, though.
    ///
    /// .. note:: This function can only be called when the contract is not paused.
    /// .. note:: This function can only be called by the contract owner.
    function pause() external onlyOwner {
        _pause();
    }

    /// Unpauses the contract.
    ///
    /// Once the contract is unpaused, it can be used normally.
    ///
    /// .. note:: This function can only be called when the contract is paused.
    /// .. note:: This function can only be called by the contract owner.
    function unpause() external onlyOwner {
        _unpause();
    }
}




/// The resolver.
///
/// This contract resides on the L1 chain and is tasked with receiving the
/// fill or non-fill proofs from the target L2 chain and forwarding them to
/// the :sol:contract:`RequestManager` on the source L2 chain.
contract Resolver is Ownable, RestrictedCalls {
    struct SourceChainInfo {
        address requestManager;
        address messenger;
    }

    /// Emitted when a fill or a non-fill proof is received and sent to the request manager.
    ///
    /// .. note:: In case of a non-fill proof, the ``filler`` will be zero.
    event Resolution(
        uint256 sourceChainId,
        uint256 fillChainId,
        bytes32 requestId,
        address filler,
        bytes32 fillId
    );

    /// Maps source chain IDs to source chain infos.
    mapping(uint256 => SourceChainInfo) public sourceChainInfos;

    /// Resolve the specified request.
    ///
    /// This marks the request identified by ``requestId`` as filled by ``filler``.
    /// If the ``filler`` is zero, the fill will be marked invalid.
    ///
    /// Information about the fill will be sent to the source chain's :sol:contract:`RequestManager`,
    /// using the messenger responsible for the source chain.
    ///
    /// .. note::
    ///
    ///     This function is callable only by the native L1 messenger contract,
    ///     which simply delivers the message sent from the target chain by the
    ///     Beamer's L2 :sol:interface:`messenger <IMessenger>` contract.
    ///
    /// @param requestId The request ID.
    /// @param fillId The fill ID.
    /// @param fillChainId The fill (target) chain ID.
    /// @param sourceChainId The source chain ID.
    /// @param filler The address that filled the request, or zero to invalidate the fill.
    function resolve(
        bytes32 requestId,
        bytes32 fillId,
        uint256 fillChainId,
        uint256 sourceChainId,
        address filler
    ) external restricted(fillChainId) {
        SourceChainInfo memory info = sourceChainInfos[sourceChainId];
        require(
            info.requestManager != address(0),
            "No request manager available for source chain"
        );
        require(
            info.messenger != address(0),
            "No messenger available for source chain"
        );

        bytes memory message;

        if (filler == address(0)) {
            message = abi.encodeCall(
                RequestManager.invalidateFill,
                (requestId, fillId, block.chainid)
            );
        } else {
            message = abi.encodeCall(
                RequestManager.resolveRequest,
                (requestId, fillId, block.chainid, filler)
            );
        }

        IMessenger messenger = IMessenger(info.messenger);
        messenger.sendMessage(info.requestManager, message);

        emit Resolution(sourceChainId, fillChainId, requestId, filler, fillId);
    }

    /// Add a request manager.
    ///
    /// In order to be able to send messages to the :sol:contract:`RequestManager`,
    /// the resolver contract needs to know the address of the request manager on the source
    /// chain, as well as the address of the messenger contract responsible for
    /// transferring messages to the L2 chain.
    ///
    /// .. note:: This function can only be called by the contract owner.
    ///
    /// @param chainId The source L2 chain ID.
    /// @param requestManager The request manager.
    /// @param messenger The messenger contract responsible for chain ``chainId``.
    ///                  Must implement :sol:interface:`IMessenger`.
    function addRequestManager(
        uint256 chainId,
        address requestManager,
        address messenger
    ) external onlyOwner {
        sourceChainInfos[chainId] = SourceChainInfo(requestManager, messenger);
    }
}