// File: contracts/MasterChef.sol



pragma solidity 0.8.2;

import "@openzeppelin/contracts/utils/structs/EnumerableSet.sol";
import "@openzeppelin/contracts/utils/math/SafeMath.sol";
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";

import {AnyswapV5ERC20} from "./lib/AnyswapV5ERC20.sol";

contract MasterChef is Ownable {
    using SafeMath for uint256;
    using SafeERC20 for IERC20;

    // The NEURON TOKEN
    AnyswapV5ERC20 public neuronToken;
    // Dev fund (10%, initially)
    uint256 public devFundPercentage = 10;
    // Treasury (10%, initially)
    uint256 public treasuryPercentage = 10;
    address public governance;
    // Dev address.
    address public devaddr;
    address public treasuryAddress;
    // Block number when bonus NEURON period ends.
    uint256 public bonusEndBlock;
    // NEURON tokens created per block.
    uint256 public neuronTokenPerBlock;
    // Bonus muliplier for early nueron makers.
    uint256 public constant BONUS_MULTIPLIER = 10;

    // The block number when NEURON mining starts.
    uint256 public startBlock;

    address public distributor;
    uint256 public distributorLastRewardBlock;

    // Events
    event Recovered(address token, uint256 amount);
    event Deposit(address indexed user, uint256 indexed pid, uint256 amount);
    event Withdraw(address indexed user, uint256 indexed pid, uint256 amount);
    event EmergencyWithdraw(
        address indexed user,
        uint256 indexed pid,
        uint256 amount
    );

    modifier onlyGovernance() {
        require(
            governance == _msgSender(),
            "Governance: caller is not the governance"
        );
        _;
    }

    constructor(
        address _neuronToken,
        address _governance,
        address _devaddr,
        address _treasuryAddress,
        uint256 _neuronTokenPerBlock,
        uint256 _startBlock,
        uint256 _bonusEndBlock
    ) {
        neuronToken = AnyswapV5ERC20(_neuronToken);
        governance = _governance;
        devaddr = _devaddr;
        treasuryAddress = _treasuryAddress;

        distributorLastRewardBlock = block.number > startBlock
            ? block.number
            : startBlock;

        neuronTokenPerBlock = _neuronTokenPerBlock;
        startBlock = _startBlock;
        bonusEndBlock = _bonusEndBlock;
    }

    // Return reward multiplier over the given _from to _to block.
    function getMultiplier(uint256 _from, uint256 _to)
        public
        view
        returns (uint256)
    {
        if (_to <= bonusEndBlock) {
            return _to.sub(_from).mul(BONUS_MULTIPLIER);
        } else if (_from >= bonusEndBlock) {
            return _to.sub(_from);
        } else {
            return
                bonusEndBlock.sub(_from).mul(BONUS_MULTIPLIER).add(
                    _to.sub(bonusEndBlock)
                );
        }
    }

    function collect() external {
        require(msg.sender == distributor, "Only distributor can collect");
        uint256 multiplier = getMultiplier(
            distributorLastRewardBlock,
            block.number
        );
        distributorLastRewardBlock = block.number;
        uint256 neuronTokenReward = multiplier.mul(neuronTokenPerBlock);
        neuronToken.mint(devaddr, neuronTokenReward.div(100).mul(devFundPercentage));
        neuronToken.mint(treasuryAddress, neuronTokenReward.div(100).mul(treasuryPercentage));
        neuronToken.mint(distributor, neuronTokenReward);
    }

    // Safe neuronToken transfer function, just in case if rounding error causes pool to not have enough NEURs.
    function safeNeuronTokenTransfer(address _to, uint256 _amount) internal {
        uint256 neuronTokenBalance = neuronToken.balanceOf(address(this));
        if (_amount > neuronTokenBalance) {
            neuronToken.transfer(_to, neuronTokenBalance);
        } else {
            neuronToken.transfer(_to, _amount);
        }
    }

    // Update dev address by the previous dev.
    function setDevAddr(address _devaddr) external {
        require(msg.sender == devaddr, "dev: wut?");
        devaddr = _devaddr;
    }

    // **** Additional functions separate from the original masterchef contract ****

    function setNeuronTokenPerBlock(uint256 _neuronTokenPerBlock)
        external
        onlyGovernance
    {
        require(_neuronTokenPerBlock > 0, "!neuronTokenPerBlock-0");

        neuronTokenPerBlock = _neuronTokenPerBlock;
    }

    function setBonusEndBlock(uint256 _bonusEndBlock) external onlyGovernance {
        bonusEndBlock = _bonusEndBlock;
    }

    function setDevFundPercentage(uint256 _devFundPercentage)
        external
        onlyGovernance
    {
        require(_devFundPercentage > 0, "!devFundPercentage-0");
        devFundPercentage = _devFundPercentage;
    }

    function setTreasuryPercentage(uint256 _treasuryPercentage)
        external
        onlyGovernance
    {
        require(_treasuryPercentage > 0, "!treasuryPercentage-0");
        treasuryPercentage = _treasuryPercentage;
    }

    function setDistributor(address _distributor) external onlyGovernance {
        distributor = _distributor;
        distributorLastRewardBlock = block.number > startBlock
            ? block.number
            : startBlock;
    }
}

// File: @openzeppelin/contracts/utils/structs/EnumerableSet.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Library for managing
 * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
 * types.
 *
 * Sets have the following properties:
 *
 * - Elements are added, removed, and checked for existence in constant time
 * (O(1)).
 * - Elements are enumerated in O(n). No guarantees are made on the ordering.
 *
 * ```
 * contract Example {
 *     // Add the library methods
 *     using EnumerableSet for EnumerableSet.AddressSet;
 *
 *     // Declare a set state variable
 *     EnumerableSet.AddressSet private mySet;
 * }
 * ```
 *
 * As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`)
 * and `uint256` (`UintSet`) are supported.
 */
library EnumerableSet {
    // To implement this library for multiple types with as little code
    // repetition as possible, we write it in terms of a generic Set type with
    // bytes32 values.
    // The Set implementation uses private functions, and user-facing
    // implementations (such as AddressSet) are just wrappers around the
    // underlying Set.
    // This means that we can only create new EnumerableSets for types that fit
    // in bytes32.

    struct Set {
        // Storage of set values
        bytes32[] _values;
        // Position of the value in the `values` array, plus 1 because index 0
        // means a value is not in the set.
        mapping(bytes32 => uint256) _indexes;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function _add(Set storage set, bytes32 value) private returns (bool) {
        if (!_contains(set, value)) {
            set._values.push(value);
            // The value is stored at length-1, but we add 1 to all indexes
            // and use 0 as a sentinel value
            set._indexes[value] = set._values.length;
            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function _remove(Set storage set, bytes32 value) private returns (bool) {
        // We read and store the value's index to prevent multiple reads from the same storage slot
        uint256 valueIndex = set._indexes[value];

        if (valueIndex != 0) {
            // Equivalent to contains(set, value)
            // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
            // the array, and then remove the last element (sometimes called as 'swap and pop').
            // This modifies the order of the array, as noted in {at}.

            uint256 toDeleteIndex = valueIndex - 1;
            uint256 lastIndex = set._values.length - 1;

            if (lastIndex != toDeleteIndex) {
                bytes32 lastvalue = set._values[lastIndex];

                // Move the last value to the index where the value to delete is
                set._values[toDeleteIndex] = lastvalue;
                // Update the index for the moved value
                set._indexes[lastvalue] = valueIndex; // Replace lastvalue's index to valueIndex
            }

            // Delete the slot where the moved value was stored
            set._values.pop();

            // Delete the index for the deleted slot
            delete set._indexes[value];

            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function _contains(Set storage set, bytes32 value) private view returns (bool) {
        return set._indexes[value] != 0;
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function _length(Set storage set) private view returns (uint256) {
        return set._values.length;
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function _at(Set storage set, uint256 index) private view returns (bytes32) {
        return set._values[index];
    }

    // Bytes32Set

    struct Bytes32Set {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _add(set._inner, value);
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _remove(set._inner, value);
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(Bytes32Set storage set, bytes32 value) internal view returns (bool) {
        return _contains(set._inner, value);
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(Bytes32Set storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(Bytes32Set storage set, uint256 index) internal view returns (bytes32) {
        return _at(set._inner, index);
    }

    // AddressSet

    struct AddressSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(AddressSet storage set, address value) internal returns (bool) {
        return _add(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(AddressSet storage set, address value) internal returns (bool) {
        return _remove(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(AddressSet storage set, address value) internal view returns (bool) {
        return _contains(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(AddressSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(AddressSet storage set, uint256 index) internal view returns (address) {
        return address(uint160(uint256(_at(set._inner, index))));
    }

    // UintSet

    struct UintSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(UintSet storage set, uint256 value) internal returns (bool) {
        return _add(set._inner, bytes32(value));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(UintSet storage set, uint256 value) internal returns (bool) {
        return _remove(set._inner, bytes32(value));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(UintSet storage set, uint256 value) internal view returns (bool) {
        return _contains(set._inner, bytes32(value));
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function length(UintSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(UintSet storage set, uint256 index) internal view returns (uint256) {
        return uint256(_at(set._inner, index));
    }
}

// File: @openzeppelin/contracts/utils/math/SafeMath.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

// CAUTION
// This version of SafeMath should only be used with Solidity 0.8 or later,
// because it relies on the compiler's built in overflow checks.

/**
 * @dev Wrappers over Solidity's arithmetic operations.
 *
 * NOTE: `SafeMath` is no longer needed starting with Solidity 0.8. The compiler
 * now has built in overflow checking.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            uint256 c = a + b;
            if (c < a) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the substraction of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b > a) return (false, 0);
            return (true, a - b);
        }
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
            // benefit is lost if 'b' is also tested.
            // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
            if (a == 0) return (true, 0);
            uint256 c = a * b;
            if (c / a != b) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the division of two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a / b);
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a % b);
        }
    }

    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        return a + b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return a - b;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        return a * b;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator.
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return a % b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {trySub}.
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b <= a, errorMessage);
            return a - b;
        }
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a / b;
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting with custom message when dividing by zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryMod}.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a % b;
        }
    }
}

// File: @openzeppelin/contracts/token/ERC20/ERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "./IERC20.sol";
import "./extensions/IERC20Metadata.sol";
import "../../utils/Context.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 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:
     *
     * - `recipient` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(_msgSender(), recipient, 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}.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        _approve(_msgSender(), 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
    ) public virtual override returns (bool) {
        _transfer(sender, recipient, amount);

        uint256 currentAllowance = _allowances[sender][_msgSender()];
        require(currentAllowance >= amount, "ERC20: transfer amount exceeds allowance");
        unchecked {
            _approve(sender, _msgSender(), currentAllowance - 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) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][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) {
        uint256 currentAllowance = _allowances[_msgSender()][spender];
        require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
        unchecked {
            _approve(_msgSender(), spender, currentAllowance - subtractedValue);
        }

        return true;
    }

    /**
     * @dev Moves `amount` of tokens from `sender` to `recipient`.
     *
     * 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:
     *
     * - `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 {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(sender, recipient, amount);

        uint256 senderBalance = _balances[sender];
        require(senderBalance >= amount, "ERC20: transfer amount exceeds balance");
        unchecked {
            _balances[sender] = senderBalance - amount;
        }
        _balances[recipient] += amount;

        emit Transfer(sender, recipient, amount);

        _afterTokenTransfer(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:
     *
     * - `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;
        _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;
        }
        _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 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 {}
}

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



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

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

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _setOwner(_msgSender());
    }

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

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

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

    function _setOwner(address newOwner) private {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// File: @openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "../IERC20.sol";
import "../../../utils/Address.sol";

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using Address for address;

    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));
        }
    }

    /**
     * @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");
        }
    }
}

// File: contracts/lib/AnyswapV5ERC20.sol



// SPDX-License-Identifier: GPL-3.0-or-later

pragma solidity 0.8.2;

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

    function decimals() external view returns (uint8);

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

    function transfer(address recipient, uint256 amount)
        external
        returns (bool);

    function allowance(address owner, address spender)
        external
        view
        returns (uint256);

    function approve(address spender, uint256 amount) external returns (bool);

    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);

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

    function transferWithPermit(
        address target,
        address to,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (bool);

    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(
        address indexed owner,
        address indexed spender,
        uint256 value
    );
}

/**
 * @dev Interface of the ERC2612 standard as defined in the EIP.
 *
 * Adds the {permit} method, which can be used to change one's
 * {IERC20-allowance} without having to send a transaction, by signing a
 * message. This allows users to spend tokens without having to hold Ether.
 *
 * See https://eips.ethereum.org/EIPS/eip-2612.
 */
interface IERC2612 {
    /**
     * @dev Returns the current ERC2612 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 Wrapped ERC-20 v10 (AnyswapV3ERC20) is an ERC-20 ERC-20 wrapper. You can `deposit` ERC-20 and obtain an AnyswapV3ERC20 balance which can then be operated as an ERC-20 token. You can
/// `withdraw` ERC-20 from AnyswapV3ERC20, which will then burn AnyswapV3ERC20 token in your wallet. The amount of AnyswapV3ERC20 token in any wallet is always identical to the
/// balance of ERC-20 deposited minus the ERC-20 withdrawn with that specific wallet.
interface IAnyswapV3ERC20 is IERC20, IERC2612 {
    /// @dev Sets `value` as allowance of `spender` account over caller account's AnyswapV3ERC20 token,
    /// after which a call is executed to an ERC677-compliant contract with the `data` parameter.
    /// Emits {Approval} event.
    /// Returns boolean value indicating whether operation succeeded.
    /// For more information on approveAndCall format, see https://github.com/ethereum/EIPs/issues/677.
    function approveAndCall(
        address spender,
        uint256 value,
        bytes calldata data
    ) external returns (bool);

    /// @dev Moves `value` AnyswapV3ERC20 token from caller's account to account (`to`),
    /// after which a call is executed to an ERC677-compliant contract with the `data` parameter.
    /// A transfer to `address(0)` triggers an ERC-20 withdraw matching the sent AnyswapV3ERC20 token in favor of caller.
    /// Emits {Transfer} event.
    /// Returns boolean value indicating whether operation succeeded.
    /// Requirements:
    ///   - caller account must have at least `value` AnyswapV3ERC20 token.
    /// For more information on transferAndCall format, see https://github.com/ethereum/EIPs/issues/677.
    function transferAndCall(
        address to,
        uint256 value,
        bytes calldata data
    ) external returns (bool);
}

interface ITransferReceiver {
    function onTokenTransfer(
        address,
        uint256,
        bytes calldata
    ) external returns (bool);
}

interface IApprovalReceiver {
    function onTokenApproval(
        address,
        uint256,
        bytes calldata
    ) external returns (bool);
}

library Address {
    function isContract(address account) internal view returns (bool) {
        bytes32 codehash;

            bytes32 accountHash
         = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            codehash := extcodehash(account)
        }
        return (codehash != 0x0 && codehash != accountHash);
    }
}

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)
        );
    }

    function safeApprove(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        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 callOptionalReturn(IERC20 token, bytes memory data) private {
        require(address(token).isContract(), "SafeERC20: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = address(token).call(data);
        require(success, "SafeERC20: low-level call failed");

        if (returndata.length > 0) {
            // Return data is optional
            // solhint-disable-next-line max-line-length
            require(
                abi.decode(returndata, (bool)),
                "SafeERC20: ERC20 operation did not succeed"
            );
        }
    }
}

contract AnyswapV5ERC20 is IAnyswapV3ERC20 {
    using SafeERC20 for IERC20;
    string public name;
    string public symbol;
    uint8 public immutable override decimals;

    address public immutable underlying;

    bytes32 public constant PERMIT_TYPEHASH =
        keccak256(
            "Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)"
        );
    bytes32 public constant TRANSFER_TYPEHASH =
        keccak256(
            "Transfer(address owner,address to,uint256 value,uint256 nonce,uint256 deadline)"
        );
    bytes32 public immutable DOMAIN_SEPARATOR;

    /// @dev Records amount of AnyswapV3ERC20 token owned by account.
    mapping(address => uint256) public override balanceOf;
    uint256 private _totalSupply;

    // init flag for setting immediate vault, needed for CREATE2 support
    bool private _init;

    // flag to enable/disable swapout vs vault.burn so multiple events are triggered
    bool private _vaultOnly;

    // configurable delay for timelock functions
    // BEFORE_DEPLOY discuss delay. 2 days (default value) maybe too much. Now set to 0 for testing
    // uint256 public delay = 2 * 24 * 3600;
    uint256 public delay = 0;

    // set of minters, can be this bridge or other bridges
    mapping(address => bool) public isMinter;
    address[] public minters;

    // primary controller of the token contract
    address public vault;

    address public pendingMinter;
    uint256 public delayMinter;

    address public pendingVault;
    uint256 public delayVault;

    uint256 public pendingDelay;
    uint256 public delayDelay;

    modifier onlyAuth() {
        require(isMinter[msg.sender], "AnyswapV4ERC20: FORBIDDEN");
        _;
    }

    modifier onlyVault() {
        require(msg.sender == mpc(), "AnyswapV3ERC20: FORBIDDEN");
        _;
    }

    function owner() public view returns (address) {
        return mpc();
    }

    function mpc() public view returns (address) {
        if (block.timestamp >= delayVault) {
            return pendingVault;
        }
        return vault;
    }

    function setVaultOnly(bool enabled) external onlyVault {
        _vaultOnly = enabled;
    }

    function initVault(address _vault) external onlyVault {
        require(_init);
        vault = _vault;
        pendingVault = _vault;
        isMinter[_vault] = true;
        minters.push(_vault);
        delayVault = block.timestamp;
        _init = false;
    }

    function setMinter(address _auth) external onlyVault {
        pendingMinter = _auth;
        delayMinter = block.timestamp + delay;
    }

    function setVault(address _vault) external onlyVault {
        pendingVault = _vault;
        delayVault = block.timestamp + delay;
    }

    function applyVault() external onlyVault {
        require(block.timestamp >= delayVault);
        vault = pendingVault;
    }

    function applyMinter() external onlyVault {
        require(block.timestamp >= delayMinter);
        isMinter[pendingMinter] = true;
        minters.push(pendingMinter);
    }

    // No time delay revoke minter emergency function
    function revokeMinter(address _auth) external onlyVault {
        isMinter[_auth] = false;
    }

    function getAllMinters() external view returns (address[] memory) {
        return minters;
    }

    function changeVault(address newVault) external onlyVault returns (bool) {
        require(newVault != address(0), "AnyswapV3ERC20: address(0x0)");
        pendingVault = newVault;
        delayVault = block.timestamp + delay;
        emit LogChangeVault(vault, pendingVault, delayVault);
        return true;
    }

    function changeMPCOwner(address newVault) public onlyVault returns (bool) {
        require(newVault != address(0), "AnyswapV3ERC20: address(0x0)");
        pendingVault = newVault;
        delayVault = block.timestamp + delay;
        emit LogChangeMPCOwner(vault, pendingVault, delayVault);
        return true;
    }

    function mint(address to, uint256 amount) external onlyAuth returns (bool) {
        _mint(to, amount);
        return true;
    }

    function burn(address from, uint256 amount)
        external
        onlyAuth
        returns (bool)
    {
        require(from != address(0), "AnyswapV3ERC20: address(0x0)");
        _burn(from, amount);
        return true;
    }

    function Swapin(
        bytes32 txhash,
        address account,
        uint256 amount
    ) public onlyAuth returns (bool) {
        _mint(account, amount);
        emit LogSwapin(txhash, account, amount);
        return true;
    }

    function Swapout(uint256 amount, address bindaddr) public returns (bool) {
        require(!_vaultOnly, "AnyswapV4ERC20: onlyAuth");
        require(bindaddr != address(0), "AnyswapV3ERC20: address(0x0)");
        _burn(msg.sender, amount);
        emit LogSwapout(msg.sender, bindaddr, amount);
        return true;
    }

    /// @dev Records current ERC2612 nonce for account. This value must be included whenever signature is generated for {permit}.
    /// Every successful call to {permit} increases account's nonce by one. This prevents signature from being used multiple times.
    mapping(address => uint256) public override nonces;

    /// @dev Records number of AnyswapV3ERC20 token that account (second) will be allowed to spend on behalf of another account (first) through {transferFrom}.
    mapping(address => mapping(address => uint256)) public override allowance;

    event LogChangeVault(
        address indexed oldVault,
        address indexed newVault,
        uint256 indexed effectiveTime
    );
    event LogChangeMPCOwner(
        address indexed oldOwner,
        address indexed newOwner,
        uint256 indexed effectiveHeight
    );
    event LogSwapin(
        bytes32 indexed txhash,
        address indexed account,
        uint256 amount
    );
    event LogSwapout(
        address indexed account,
        address indexed bindaddr,
        uint256 amount
    );
    event LogAddAuth(address indexed auth, uint256 timestamp);

    constructor(
        string memory _name,
        string memory _symbol,
        uint8 _decimals,
        address _underlying,
        address _vault
    ) {
        name = _name;
        symbol = _symbol;
        decimals = _decimals;
        underlying = _underlying;
        if (_underlying != address(0x0)) {
            require(_decimals == IERC20(_underlying).decimals());
        }

        // Use init to allow for CREATE2 accross all chains
        _init = true;

        // Disable/Enable swapout for v1 tokens vs mint/burn for v3 tokens
        _vaultOnly = false;

        vault = _vault;
        pendingVault = _vault;
        delayVault = block.timestamp;

        uint256 chainId;
        assembly {
            chainId := chainid()
        }
        DOMAIN_SEPARATOR = keccak256(
            abi.encode(
                keccak256(
                    "EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"
                ),
                keccak256(bytes(name)),
                keccak256(bytes("1")),
                chainId,
                address(this)
            )
        );
    }

    /// @dev Returns the total supply of AnyswapV3ERC20 token as the ETH held in this contract.
    function totalSupply() external view override returns (uint256) {
        return _totalSupply;
    }

    function depositWithPermit(
        address target,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s,
        address to
    ) external returns (uint256) {
        IERC20(underlying).permit(
            target,
            address(this),
            value,
            deadline,
            v,
            r,
            s
        );
        IERC20(underlying).safeTransferFrom(target, address(this), value);
        return _deposit(value, to);
    }

    function depositWithTransferPermit(
        address target,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s,
        address to
    ) external returns (uint256) {
        IERC20(underlying).transferWithPermit(
            target,
            address(this),
            value,
            deadline,
            v,
            r,
            s
        );
        return _deposit(value, to);
    }

    function deposit() external returns (uint256) {
        uint256 _amount = IERC20(underlying).balanceOf(msg.sender);
        IERC20(underlying).safeTransferFrom(msg.sender, address(this), _amount);
        return _deposit(_amount, msg.sender);
    }

    function deposit(uint256 amount) external returns (uint256) {
        IERC20(underlying).safeTransferFrom(msg.sender, address(this), amount);
        return _deposit(amount, msg.sender);
    }

    function deposit(uint256 amount, address to) external returns (uint256) {
        IERC20(underlying).safeTransferFrom(msg.sender, address(this), amount);
        return _deposit(amount, to);
    }

    function depositVault(uint256 amount, address to)
        external
        onlyVault
        returns (uint256)
    {
        return _deposit(amount, to);
    }

    function _deposit(uint256 amount, address to) internal returns (uint256) {
        require(underlying != address(0x0) && underlying != address(this));
        _mint(to, amount);
        return amount;
    }

    function withdraw() external returns (uint256) {
        return _withdraw(msg.sender, balanceOf[msg.sender], msg.sender);
    }

    function withdraw(uint256 amount) external returns (uint256) {
        return _withdraw(msg.sender, amount, msg.sender);
    }

    function withdraw(uint256 amount, address to) external returns (uint256) {
        return _withdraw(msg.sender, amount, to);
    }

    function withdrawVault(
        address from,
        uint256 amount,
        address to
    ) external onlyVault returns (uint256) {
        return _withdraw(from, amount, to);
    }

    function _withdraw(
        address from,
        uint256 amount,
        address to
    ) internal returns (uint256) {
        _burn(from, amount);
        IERC20(underlying).safeTransfer(to, amount);
        return 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 {
        require(account != address(0), "ERC20: mint to the zero address");

        _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 {
        require(account != address(0), "ERC20: burn from the zero address");

        balanceOf[account] -= amount;
        _totalSupply -= amount;
        emit Transfer(account, address(0), amount);
    }

    /// @dev Sets `value` as allowance of `spender` account over caller account's AnyswapV3ERC20 token.
    /// Emits {Approval} event.
    /// Returns boolean value indicating whether operation succeeded.
    function approve(address spender, uint256 value)
        external
        override
        returns (bool)
    {
        // _approve(msg.sender, spender, value);
        allowance[msg.sender][spender] = value;
        emit Approval(msg.sender, spender, value);

        return true;
    }

    /// @dev Sets `value` as allowance of `spender` account over caller account's AnyswapV3ERC20 token,
    /// after which a call is executed to an ERC677-compliant contract with the `data` parameter.
    /// Emits {Approval} event.
    /// Returns boolean value indicating whether operation succeeded.
    /// For more information on approveAndCall format, see https://github.com/ethereum/EIPs/issues/677.
    function approveAndCall(
        address spender,
        uint256 value,
        bytes calldata data
    ) external override returns (bool) {
        // _approve(msg.sender, spender, value);
        allowance[msg.sender][spender] = value;
        emit Approval(msg.sender, spender, value);

        return
            IApprovalReceiver(spender).onTokenApproval(msg.sender, value, data);
    }

    /// @dev Sets `value` as allowance of `spender` account over `owner` account's AnyswapV3ERC20 token, given `owner` account's signed approval.
    /// Emits {Approval} event.
    /// Requirements:
    ///   - `deadline` must be timestamp in future.
    ///   - `v`, `r` and `s` must be valid `secp256k1` signature from `owner` account over EIP712-formatted function arguments.
    ///   - the signature must use `owner` account's current nonce (see {nonces}).
    ///   - the signer cannot be zero address and must be `owner` account.
    /// For more information on signature format, see https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP section].
    /// AnyswapV3ERC20 token implementation adapted from https://github.com/albertocuestacanada/ERC20Permit/blob/master/contracts/ERC20Permit.sol.
    function permit(
        address target,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external override {
        require(block.timestamp <= deadline, "AnyswapV3ERC20: Expired permit");

        bytes32 hashStruct = keccak256(
            abi.encode(
                PERMIT_TYPEHASH,
                target,
                spender,
                value,
                nonces[target]++,
                deadline
            )
        );

        require(
            verifyEIP712(target, hashStruct, v, r, s) ||
                verifyPersonalSign(target, hashStruct, v, r, s)
        );

        // _approve(owner, spender, value);
        allowance[target][spender] = value;
        emit Approval(target, spender, value);
    }

    function transferWithPermit(
        address target,
        address to,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external override returns (bool) {
        require(block.timestamp <= deadline, "AnyswapV3ERC20: Expired permit");

        bytes32 hashStruct = keccak256(
            abi.encode(
                TRANSFER_TYPEHASH,
                target,
                to,
                value,
                nonces[target]++,
                deadline
            )
        );

        require(
            verifyEIP712(target, hashStruct, v, r, s) ||
                verifyPersonalSign(target, hashStruct, v, r, s)
        );

        require(to != address(0) || to != address(this));

        uint256 balance = balanceOf[target];
        require(
            balance >= value,
            "AnyswapV3ERC20: transfer amount exceeds balance"
        );

        balanceOf[target] = balance - value;
        balanceOf[to] += value;
        emit Transfer(target, to, value);

        return true;
    }

    function verifyEIP712(
        address target,
        bytes32 hashStruct,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal view returns (bool) {
        bytes32 hash = keccak256(
            abi.encodePacked("\x19\x01", DOMAIN_SEPARATOR, hashStruct)
        );
        address signer = ecrecover(hash, v, r, s);
        return (signer != address(0) && signer == target);
    }

    function verifyPersonalSign(
        address target,
        bytes32 hashStruct,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal view returns (bool) {
        bytes32 hash = prefixed(hashStruct);
        address signer = ecrecover(hash, v, r, s);
        return (signer != address(0) && signer == target);
    }

    // Builds a prefixed hash to mimic the behavior of eth_sign.
    function prefixed(bytes32 hash) internal view returns (bytes32) {
        return
            keccak256(
                abi.encodePacked(
                    "\x19Ethereum Signed Message:\n32",
                    DOMAIN_SEPARATOR,
                    hash
                )
            );
    }

    /// @dev Moves `value` AnyswapV3ERC20 token from caller's account to account (`to`).
    /// A transfer to `address(0)` triggers an ETH withdraw matching the sent AnyswapV3ERC20 token in favor of caller.
    /// Emits {Transfer} event.
    /// Returns boolean value indicating whether operation succeeded.
    /// Requirements:
    ///   - caller account must have at least `value` AnyswapV3ERC20 token.
    function transfer(address to, uint256 value)
        external
        override
        returns (bool)
    {
        require(to != address(0) || to != address(this));
        uint256 balance = balanceOf[msg.sender];
        require(
            balance >= value,
            "AnyswapV3ERC20: transfer amount exceeds balance"
        );

        balanceOf[msg.sender] = balance - value;
        balanceOf[to] += value;
        emit Transfer(msg.sender, to, value);

        return true;
    }

    /// @dev Moves `value` AnyswapV3ERC20 token from account (`from`) to account (`to`) using allowance mechanism.
    /// `value` is then deducted from caller account's allowance, unless set to `type(uint256).max`.
    /// A transfer to `address(0)` triggers an ETH withdraw matching the sent AnyswapV3ERC20 token in favor of caller.
    /// Emits {Approval} event to reflect reduced allowance `value` for caller account to spend from account (`from`),
    /// unless allowance is set to `type(uint256).max`
    /// Emits {Transfer} event.
    /// Returns boolean value indicating whether operation succeeded.
    /// Requirements:
    ///   - `from` account must have at least `value` balance of AnyswapV3ERC20 token.
    ///   - `from` account must have approved caller to spend at least `value` of AnyswapV3ERC20 token, unless `from` and caller are the same account.
    function transferFrom(
        address from,
        address to,
        uint256 value
    ) external override returns (bool) {
        require(to != address(0) || to != address(this));
        if (from != msg.sender) {
            // _decreaseAllowance(from, msg.sender, value);
            uint256 allowed = allowance[from][msg.sender];
            if (allowed != type(uint256).max) {
                require(
                    allowed >= value,
                    "AnyswapV3ERC20: request exceeds allowance"
                );
                uint256 reduced = allowed - value;
                allowance[from][msg.sender] = reduced;
                emit Approval(from, msg.sender, reduced);
            }
        }

        uint256 balance = balanceOf[from];
        require(
            balance >= value,
            "AnyswapV3ERC20: transfer amount exceeds balance"
        );

        balanceOf[from] = balance - value;
        balanceOf[to] += value;
        emit Transfer(from, to, value);

        return true;
    }

    /// @dev Moves `value` AnyswapV3ERC20 token from caller's account to account (`to`),
    /// after which a call is executed to an ERC677-compliant contract with the `data` parameter.
    /// A transfer to `address(0)` triggers an ETH withdraw matching the sent AnyswapV3ERC20 token in favor of caller.
    /// Emits {Transfer} event.
    /// Returns boolean value indicating whether operation succeeded.
    /// Requirements:
    ///   - caller account must have at least `value` AnyswapV3ERC20 token.
    /// For more information on transferAndCall format, see https://github.com/ethereum/EIPs/issues/677.
    function transferAndCall(
        address to,
        uint256 value,
        bytes calldata data
    ) external override returns (bool) {
        require(to != address(0) || to != address(this));

        uint256 balance = balanceOf[msg.sender];
        require(
            balance >= value,
            "AnyswapV3ERC20: transfer amount exceeds balance"
        );

        balanceOf[msg.sender] = balance - value;
        balanceOf[to] += value;
        emit Transfer(msg.sender, to, value);

        return ITransferReceiver(to).onTokenTransfer(msg.sender, value, data);
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

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

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

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

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

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

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

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

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

// File: @openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "../IERC20.sol";

/**
 * @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);
}

// File: @openzeppelin/contracts/utils/Context.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

// File: @openzeppelin/contracts/utils/Address.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @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
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 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 functionCall(target, data, "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");
        require(isContract(target), "Address: call to non-contract");

        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return _verifyCallResult(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) {
        require(isContract(target), "Address: static call to non-contract");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return _verifyCallResult(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) {
        require(isContract(target), "Address: delegate call to non-contract");

        (bool success, bytes memory returndata) = target.delegatecall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    function _verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) private pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // 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

                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}