// Source: contracts/interchain-token/ERC20Permit.sol

pragma solidity ^0.8.0;

// SPDX-License-Identifier: MIT

// File @axelar-network/axelar-gmp-sdk-solidity/contracts/interfaces/IERC20.sol@v6.0.4

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    error InvalidAccount();

    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

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

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

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

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

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

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

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

// File contracts/interchain-token/ERC20.sol

/**
 * @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.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin guidelines: functions revert instead
 * of 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 IERC20 {
    mapping(address => uint256) public override balanceOf;

    mapping(address => mapping(address => uint256)) public override allowance;

    uint256 public override totalSupply;
    uint256 internal constant UINT256_MAX = type(uint256).max;

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `recipient` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address recipient, uint256 amount) external virtual override returns (bool) {
        _transfer(msg.sender, recipient, amount);
        return true;
    }

    /**
     * @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) external virtual override returns (bool) {
        _approve(msg.sender, 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}.
     *
     * Requirements:
     *
     * - `sender` and `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     * - the caller must have allowance for ``sender``'s tokens of at least
     * `amount`.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external virtual override returns (bool) {
        uint256 _allowance = allowance[sender][msg.sender];

        if (_allowance != UINT256_MAX) {
            _approve(sender, msg.sender, _allowance - amount);
        }

        _transfer(sender, recipient, 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) external virtual returns (bool) {
        _approve(msg.sender, spender, allowance[msg.sender][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) external virtual returns (bool) {
        _approve(msg.sender, spender, allowance[msg.sender][spender] - subtractedValue);
        return true;
    }

    /**
     * @dev Moves tokens `amount` from `sender` to `recipient`.
     *
     * This is 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:
     *
     * - `sender` cannot be the zero address.
     * - `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     */
    function _transfer(address sender, address recipient, uint256 amount) internal virtual {
        if (sender == address(0) || recipient == address(0)) revert InvalidAccount();

        balanceOf[sender] -= amount;
        balanceOf[recipient] += amount;
        emit Transfer(sender, recipient, 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:
     *
     * - `to` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal virtual {
        if (account == address(0)) revert InvalidAccount();

        totalSupply += amount;
        balanceOf[account] += amount;
        emit Transfer(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 {
        if (account == address(0)) revert InvalidAccount();

        balanceOf[account] -= amount;
        totalSupply -= amount;
        emit Transfer(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 {
        if (owner == address(0) || spender == address(0)) revert InvalidAccount();

        allowance[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }
}

// File @axelar-network/axelar-cgp-solidity/contracts/interfaces/IERC20Permit.sol@v6.4.0

interface IERC20Permit {
    function DOMAIN_SEPARATOR() external view returns (bytes32);

    function nonces(address account) external view returns (uint256);

    function permit(address issuer, address spender, uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s) external;
}

// File contracts/interchain-token/ERC20Permit.sol

/**
 * @title ERC20Permit Contract
 * @dev Extension of ERC20 to include permit functionality (EIP-2612).
 * Allows for approval of ERC20 tokens by signature rather than transaction.
 */
abstract contract ERC20Permit is IERC20, IERC20Permit, ERC20 {
    error PermitExpired();
    error InvalidS();
    error InvalidV();
    error InvalidSignature();

    /**
     * @dev Represents hash of the EIP-712 Domain Separator.
     */
    bytes32 public nameHash;

    string private constant EIP191_PREFIX_FOR_EIP712_STRUCTURED_DATA = '\x19\x01';

    // keccak256('EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)')
    bytes32 private constant DOMAIN_TYPE_SIGNATURE_HASH = bytes32(0x8b73c3c69bb8fe3d512ecc4cf759cc79239f7b179b0ffacaa9a75d522b39400f);

    // keccak256('Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)')
    bytes32 private constant PERMIT_SIGNATURE_HASH = bytes32(0x6e71edae12b1b97f4d1f60370fef10105fa2faae0126114a169c64845d6126c9);

    /**
     * @dev Mapping of nonces for each address.
     */
    mapping(address => uint256) public nonces;

    /**
     * @notice Internal function to set the token name hash
     * @param name The token name
     */
    function _setNameHash(string memory name) internal {
        nameHash = keccak256(bytes(name));
    }

    /**
     * @notice Calculates the domain separator.
     * @dev This is not cached because chainid can change on chain forks.
     */
    // solhint-disable func-name-mixedcase
    // slither-disable-next-line naming-convention
    function DOMAIN_SEPARATOR() public view returns (bytes32) {
        return keccak256(abi.encode(DOMAIN_TYPE_SIGNATURE_HASH, nameHash, keccak256(bytes('1')), block.chainid, address(this)));
    }

    // solhint-enable func-name-mixedcase

    /**
     * @notice Permit the designated spender to spend the holder's tokens
     * @dev The permit function is used to allow a holder to designate a spender
     * to spend tokens on their behalf via a signed message.
     * @param issuer The address of the token holder
     * @param spender The address of the designated spender
     * @param value The number of tokens to be spent
     * @param deadline The time at which the permission to spend expires
     * @param v The recovery id of the signature
     * @param r Half of the ECDSA signature pair
     * @param s Half of the ECDSA signature pair
     */
    function permit(address issuer, address spender, uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s) external {
        if (block.timestamp > deadline) revert PermitExpired();

        if (uint256(s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) revert InvalidS();

        if (v != 27 && v != 28) revert InvalidV();

        bytes32 digest = keccak256(
            abi.encodePacked(
                EIP191_PREFIX_FOR_EIP712_STRUCTURED_DATA,
                DOMAIN_SEPARATOR(),
                keccak256(abi.encode(PERMIT_SIGNATURE_HASH, issuer, spender, value, nonces[issuer]++, deadline))
            )
        );

        address recoveredAddress = ecrecover(digest, v, r, s);

        if (recoveredAddress != issuer) revert InvalidSignature();

        // _approve will revert if issuer is address(0x0)
        _approve(issuer, spender, value);
    }
}