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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

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

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

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

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

    /**
     * @dev 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);
    }
}

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC20/ERC20.sol)

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 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;
        }
        _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;
        _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 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 {}
}

// File: @openzeppelin/contracts/token/ERC20/extensions/draft-IERC20Permit.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/draft-IERC20Permit.sol)

pragma solidity ^0.8.0;

/**
 * @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);
}

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)

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/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @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);
}

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";
import "../extensions/draft-IERC20Permit.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));
        }
    }

    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");
        }
    }
}

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @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 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);
    }

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason 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 {
            // 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);
            }
        }
    }
}

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

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

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

// File: contracts/interfaces/ILocker.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

interface ILocker {

    struct UserUnlocking {
        uint256 startTime;
        uint256 endTime;
        uint256 amountInCoolDown; // total amount comitted to the unlock slot, never changes except when reseting slot
    }    

    function getUserUnlockingSchedule(address _user) external view returns (UserUnlocking[] memory slots);
    function getUserAmountInCoolDown(address _user) external view returns (uint256);
    function totalLocked() external view returns (uint256);
    function getFullyUnlock(address _user) external view returns(uint256 unlockedAmount);
    function getRewardablePercentWAD(address _user) external view returns(uint256 percent);
    function totalAmountInCoolDown() external view returns (uint256);
    function getUserNthUnlockSlot(address _user, uint256 n) external view returns (
        uint256 startTime,
        uint256 endTime,
        uint256 amountInCoolDown
    );

    function getUserUnlockSlotLength(address _user) external view returns (uint256);
    function getNextAvailableUnlockSlot(address _user) external view returns (uint256);
    function getUserTotalLocked(address _user) external view returns (uint256);
    function lock(uint256 _amount) external;
    function lockFor(uint256 _amount, address _for) external;
    function startUnlock(uint256 _amountToCoolDown) external;
    function cancelUnlock(uint256 _slotIndex) external;
    function unlock(uint256 slotIndex) external;    
}
// File: contracts/interfaces/IMasterMagpie.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;
import {IERC20} from "@openzeppelin/contracts/token/ERC20/ERC20.sol";

interface IMasterMagpie {
    function poolLength() external view returns (uint256);

    function setPoolManagerStatus(address _address, bool _bool) external;

    function add(
        uint256 _allocPoint,
        address _stakingTokenToken,
        address _rewarder,
        address _helper,
        bool _helperNeedsHarvest
    ) external;

    function createRewarder(
        address _stakingToken,
        address mainRewardToken
    ) external returns (address);

    function set(
        address _stakingToken,
        uint256 _allocPoint,
        address _helper,
        address _rewarder,
        bool _helperNeedsHarvest
    ) external;

    // View function to see pending GMPs on frontend.
    function getPoolInfo(
        address token
    )
        external
        view
        returns (
            uint256 emission,
            uint256 allocpoint,
            uint256 sizeOfPool,
            uint256 totalPoint
        );

    function rewarderBonusTokenInfo(
        address _stakingToken
    )
        external
        view
        returns (
            address[] memory bonusTokenAddresses,
            string[] memory bonusTokenSymbols
        );

    function pendingTokens(
        address _stakingToken,
        address _user,
        address token
    )
        external
        view
        returns (
            uint256 _pendingGMP,
            address _bonusTokenAddress,
            string memory _bonusTokenSymbol,
            uint256 _pendingBonusToken
        );

    function allPendingTokens(
        address _stakingToken,
        address _user
    )
        external
        view
        returns (
            uint256 pendingMGP,
            address[] memory bonusTokenAddresses,
            string[] memory bonusTokenSymbols,
            uint256[] memory pendingBonusRewards
        );

    function massUpdatePools() external;

    function updatePool(address _stakingToken) external;

    function deposit(address _stakingToken, uint256 _amount) external;

    function withdraw(address _stakingToken, uint256 _amount) external;

    function depositFor(
        address _stakingToken,
        uint256 _amount,
        address sender
    ) external;

    function withdrawFor(
        address _stakingToken,
        uint256 _amount,
        address _sender
    ) external;

    function depositVlMGPFor(uint256 _amount, address sender) external;

    function withdrawVlMGPFor(uint256 _amount, address sender) external;

    function depositMWomSVFor(uint256 _amount, address sender) external;

    function withdrawMWomSVFor(uint256 _amount, address sender) external;

    function multiclaimFor(
        address[] calldata _stakingTokens,
        address[][] calldata _rewardTokens,
        address user_address
    ) external;

    function multiclaimOnBehalf(
        address[] memory _stakingTokens,
        address[][] calldata _rewardTokens,
        address user_address
    ) external;

    function emergencyWithdraw(address _stakingToken, address sender) external;

    function updateEmissionRate(uint256 _gmpPerSec) external;

    function stakingInfo(
        address _stakingToken,
        address _user
    ) external view returns (uint256 depositAmount, uint256 availableAmount);
}

// File: contracts/interfaces/ISimpleHelper.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

interface ISimpleHelper {
    function depositFor(uint256 _amount, address _for) external;
}
// File: contracts/interfaces/wombat/IAsset.sol



pragma solidity ^0.8.0;

import '@openzeppelin/contracts/token/ERC20/IERC20.sol';

interface IAsset is IERC20 {
    function cash() external view returns (uint120);
    function liability() external view returns (uint120);
}
// File: contracts/interfaces/wombat/IMWom.sol



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

pragma solidity ^0.8.0;

import { IERC20 } from "@openzeppelin/contracts/token/ERC20/ERC20.sol";

interface IMWom is IERC20 {
    function deposit(uint256 _amount) external;
    function convert(uint256 amount) external;
}
// File: contracts/interfaces/wombat/IWombatRouter.sol



pragma solidity ^0.8.0;

/**
 * @dev Interface of the VeWom
 */
interface IWombatRouter {

    /**
     * @notice Given an input asset amount and an array of token addresses, calculates the
     * maximum output token amount (accounting for fees and slippage).
     * @param tokenPath The token swap path
     * @param poolPath The token pool path
     * @param amountIn The from amount
     * @return amountOut The potential final amount user would receive
     */
    function getAmountOut(
        address[] calldata tokenPath,
        address[] calldata poolPath,
        int256 amountIn
    ) external view returns (uint256 amountOut, uint256[] memory haircuts);

    /// @notice Swaps an exact amount of input tokens for as many output tokens as possible, along the route determined by the path
    /// @param tokenPath An array of token addresses. path.length must be >= 2.
    /// @param tokenPath The first element of the path is the input token, the last element is the output token.
    /// @param poolPath An array of pool addresses. The pools where the pathTokens are contained in order.
    /// @param amountIn the amount in
    /// @param minimumamountOut the minimum amount to get for user
    /// @param to the user to send the tokens to
    /// @param deadline the deadline to respect
    /// @return amountOut received by user
    function swapExactTokensForTokens(
        address[] calldata tokenPath,
        address[] calldata poolPath,
        uint256 amountIn,
        uint256 minimumamountOut,
        address to,
        uint256 deadline
    ) external returns (uint256 amountOut);

}
// File: contracts/wombat/SmartWomConvert.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import { SafeERC20 } from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import { IERC20 } from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";

import "../interfaces/wombat/IWombatRouter.sol";
import "../interfaces/wombat/IMWom.sol";
import "../interfaces/wombat/IAsset.sol";
import "../interfaces/ISimpleHelper.sol";
import "../interfaces/IMasterMagpie.sol";
import "../interfaces/ILocker.sol";

/// @title Smart Convertor
/// @author Magpie Team

contract SmartWomConvert is ISimpleHelper, Ownable {
    using SafeERC20 for IERC20;

    /* ============ State Variables ============ */

    address public immutable mWom;
    address public immutable wom;    
    address public immutable router;
    address public immutable womMWomPool;
    address public immutable masterMagpie;
    address public immutable womAsset;

    uint256 public constant DENOMINATOR = 10000;
    uint256 public constant WAD = 1e18;
    uint256 public ratio;
    uint256 public buybackThreshold;
    ILocker public mWomSV;

    /* ============ Errors ============ */
    
    error IncorrectRatio();
    error MinRecNotMatch();
    error MustNoBeZero();
    error IncorrectThreshold();

    /* ============ Events ============ */

    event mWomConverted(address user, uint256 depositedWom, uint256 obtainedmWom, uint256 mode);

    /* ============ Constructor ============ */

    constructor(
        address _mwom,
        address _wom,
        address _mWomSV,
        address _router,
        address _womMWomPool,
        address _masterMagpie,
        address _womAsset,
        uint256 _ratio
    ) {
        mWom = _mwom;
        wom = _wom;
        router = _router;
        womMWomPool = _womMWomPool;
        masterMagpie = _masterMagpie;
        womAsset = _womAsset;
        ratio = _ratio;
        mWomSV = ILocker(_mWomSV);
        buybackThreshold = 9000;
    }

    /* ============ External Getters ============ */

    function estimateTotalConversion(uint256 _amount, uint256 _convertRatio)
        external
        view
        returns (uint256 minimumEstimatedTotal)
    {
        if (_convertRatio > DENOMINATOR)
            revert IncorrectRatio();
            
        uint256 buybackAmount = _amount - (_amount * _convertRatio / DENOMINATOR);
        uint256 convertAmount = _amount - buybackAmount;
        uint256 amountOut = 0;

        if (buybackAmount > 0) {
            address[] memory tokenPath = new address[](2);
            tokenPath[0] = wom;
            tokenPath[1] = mWom;

            address[] memory poolPath = new address[](1);
            poolPath[0] = womMWomPool;

            (amountOut, ) = IWombatRouter(router).getAmountOut(tokenPath, poolPath, int256(buybackAmount));
        }

        return (amountOut + convertAmount);
    }

    function maxSwapAmount() public view returns (uint256) {
        uint256 womCash = IAsset(womAsset).cash();
        uint256 womLiability = IAsset(womAsset).liability();
        if (womCash >= womLiability)
            return 0;

        return (womLiability - womCash) * ratio / DENOMINATOR;
    }

    function currentRatio() public view returns (uint256) {
        address[] memory tokenPath = new address[](2);
        tokenPath[0] = mWom;
        tokenPath[1] = wom;
        
        address[] memory poolPath = new address[](1);
        poolPath[0] = womMWomPool;
    
        (uint256 amountOut, ) = IWombatRouter(router).getAmountOut(tokenPath, poolPath, 1e18);
        return amountOut * DENOMINATOR / 1e18;
    }

    /* ============ External Functions ============ */

    function convert(uint256 _amountIn, uint256 _convertRatio, uint256 _minRec, uint256 _mode) external returns (uint256 obtainedmWomAmount) {
        obtainedmWomAmount = _convertFor(_amountIn, _convertRatio, _minRec, msg.sender, _mode);
    }

    function convertFor(uint256 _amountIn, uint256 _convertRatio, uint256 _minRec, address _for, uint256 _mode)
        external
        returns (uint256 obtainedmWomAmount)
    {
        obtainedmWomAmount = _convertFor(_amountIn, _convertRatio, _minRec, _for, _mode);
    }

    // should mainly used by wombat staking upon sending wom
    function smartConvert(uint256 _amountIn, uint256 _mode) external returns (uint256 obtainedmWomAmount) {
        if (_amountIn == 0) revert MustNoBeZero();

        uint256 convertRatio = DENOMINATOR;
        uint256 mWomToWom = currentRatio();

        if (mWomToWom < buybackThreshold) {
            uint256 maxSwap = maxSwapAmount();
            uint256 amountToSwap = _amountIn > maxSwap ? maxSwap : _amountIn;
            uint256 convertAmount = _amountIn - amountToSwap;
            convertRatio = convertAmount * DENOMINATOR / _amountIn;
        }

        return _convertFor(_amountIn, convertRatio, _amountIn, msg.sender, _mode);
    }

    function depositFor(uint256 _amount, address _for) override external {
        IERC20(mWom).safeTransferFrom(
            msg.sender,
            address(this),
            _amount
        );
        IERC20(mWom).safeApprove(masterMagpie, _amount);
        IMasterMagpie(masterMagpie).depositFor(mWom, _amount, _for);
    }

    function setRatio(uint256 _ratio) external onlyOwner {
        if (_ratio > DENOMINATOR)
            revert IncorrectRatio();

        ratio = _ratio;
    }

    function setBuybackThreshold(uint256 _threshold) external onlyOwner {
        if (_threshold > DENOMINATOR)
            revert IncorrectThreshold();

        buybackThreshold = _threshold;
    }

    /* ============ Internal Functions ============ */

    function _convertFor(uint256 _amount, uint256 _convertRatio, uint256 _minRec, address _for, uint256 _mode)
        internal returns (uint256 obtainedmWomAmount) {

        if (_convertRatio > DENOMINATOR)
            revert IncorrectRatio();

        IERC20(wom).safeTransferFrom(msg.sender, address(this), _amount);
        uint256 buybackAmount = _amount - (_amount * _convertRatio / DENOMINATOR);
        uint256 convertAmount = _amount - buybackAmount;
        uint256 amountRec = 0;

        if (buybackAmount > 0) {
            address[] memory tokenPath = new address[](2);
            tokenPath[0] = wom;
            tokenPath[1] = mWom;
            address[] memory poolPath = new address[](1);
            poolPath[0] = womMWomPool;
        
            IERC20(wom).safeApprove(router, buybackAmount);
            amountRec = IWombatRouter(router).swapExactTokensForTokens(
                tokenPath, poolPath, buybackAmount, 0, address(this), block.timestamp
            );
        }

        if (convertAmount > 0) {
            IERC20(wom).safeApprove(mWom, convertAmount);
            IMWom(mWom).deposit(convertAmount);
        }

        if (convertAmount + amountRec < _minRec)
            revert MinRecNotMatch();

        obtainedmWomAmount = convertAmount + amountRec;

        if (_mode == 1) {
            IERC20(mWom).safeApprove(masterMagpie, obtainedmWomAmount);
            IMasterMagpie(masterMagpie).depositFor(mWom, obtainedmWomAmount, _for);
        } else if (_mode == 2) {
            IERC20(mWom).safeApprove(address(mWomSV), obtainedmWomAmount);
            mWomSV.lockFor(obtainedmWomAmount, _for);
        } else {
            IERC20(mWom).safeTransfer(_for, obtainedmWomAmount);
        }

        emit mWomConverted(_for, _amount, obtainedmWomAmount, _mode);
    }
}