// File: @openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol



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

pragma solidity ^0.8.0;

import "../../utils/AddressUpgradeable.sol";

/**
 * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
 * behind a proxy. Since a proxied contract can't have a constructor, it's common to move constructor logic to an
 * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
 * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
 *
 * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
 * possible by providing the encoded function call as the `_data` argument to {ERC1967Proxy-constructor}.
 *
 * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
 * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
 *
 * [CAUTION]
 * ====
 * Avoid leaving a contract uninitialized.
 *
 * An uninitialized contract can be taken over by an attacker. This applies to both a proxy and its implementation
 * contract, which may impact the proxy. To initialize the implementation contract, you can either invoke the
 * initializer manually, or you can include a constructor to automatically mark it as initialized when it is deployed:
 *
 * [.hljs-theme-light.nopadding]
 * ```
 * /// @custom:oz-upgrades-unsafe-allow constructor
 * constructor() initializer {}
 * ```
 * ====
 */
abstract contract Initializable {
    /**
     * @dev Indicates that the contract has been initialized.
     */
    bool private _initialized;

    /**
     * @dev Indicates that the contract is in the process of being initialized.
     */
    bool private _initializing;

    /**
     * @dev Modifier to protect an initializer function from being invoked twice.
     */
    modifier initializer() {
        // If the contract is initializing we ignore whether _initialized is set in order to support multiple
        // inheritance patterns, but we only do this in the context of a constructor, because in other contexts the
        // contract may have been reentered.
        require(_initializing ? _isConstructor() : !_initialized, "Initializable: contract is already initialized");

        bool isTopLevelCall = !_initializing;
        if (isTopLevelCall) {
            _initializing = true;
            _initialized = true;
        }

        _;

        if (isTopLevelCall) {
            _initializing = false;
        }
    }

    /**
     * @dev Modifier to protect an initialization function so that it can only be invoked by functions with the
     * {initializer} modifier, directly or indirectly.
     */
    modifier onlyInitializing() {
        require(_initializing, "Initializable: contract is not initializing");
        _;
    }

    function _isConstructor() private view returns (bool) {
        return !AddressUpgradeable.isContract(address(this));
    }
}

// File: @openzeppelin/contracts-upgradeable/security/ReentrancyGuardUpgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (security/ReentrancyGuard.sol)

pragma solidity ^0.8.0;
import "../proxy/utils/Initializable.sol";

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
abstract contract ReentrancyGuardUpgradeable is Initializable {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    function __ReentrancyGuard_init() internal onlyInitializing {
        __ReentrancyGuard_init_unchained();
    }

    function __ReentrancyGuard_init_unchained() internal onlyInitializing {
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and making it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
    uint256[49] private __gap;
}

// File: @openzeppelin/contracts-upgradeable/utils/AddressUpgradeable.sol



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

pragma solidity ^0.8.0;

/**
 * @dev Collection of functions related to the address type
 */
library AddressUpgradeable {
    /**
     * @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 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

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

// File: @openzeppelin/contracts-upgradeable/utils/StringsUpgradeable.sol



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

pragma solidity ^0.8.0;

/**
 * @dev String operations.
 */
library StringsUpgradeable {
    bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        // Inspired by OraclizeAPI's implementation - MIT licence
        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol

        if (value == 0) {
            return "0";
        }
        uint256 temp = value;
        uint256 digits;
        while (temp != 0) {
            digits++;
            temp /= 10;
        }
        bytes memory buffer = new bytes(digits);
        while (value != 0) {
            digits -= 1;
            buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
            value /= 10;
        }
        return string(buffer);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        if (value == 0) {
            return "0x00";
        }
        uint256 temp = value;
        uint256 length = 0;
        while (temp != 0) {
            length++;
            temp >>= 8;
        }
        return toHexString(value, length);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = _HEX_SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }
}

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (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 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 {
        _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 v4.4.1 (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:
     *
     * - `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/token/ERC20/IERC20.sol



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

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
// 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/utils/SafeERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/utils/SafeERC20.sol)

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: @openzeppelin/contracts/utils/Address.sol



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

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);
    }

    /**
     * @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

                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/accumulator/BaseAccumulator.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.7;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";

import "../interfaces/ILocker.sol";
import "../interfaces/ILiquidityGauge.sol";
import { ISDTDistributor } from "../interfaces/ISDTDistributor.sol";

/// @title BaseAccumulator
/// @notice A contract that defines the functions shared by all accumulators
/// @author StakeDAO
contract BaseAccumulator {
	using SafeERC20 for IERC20;
	/* ========== STATE VARIABLES ========== */
	address public governance;
	address public locker;
	address public tokenReward;
	address public gauge;
	address public sdtDistributor;
	uint256 public claimerFee;

	/* ========== EVENTS ========== */

	event SdtDistributorUpdated(address oldDistributor, address newDistributor);
	event GaugeSet(address oldGauge, address newGauge);
	event RewardNotified(address gauge, address tokenReward, uint256 amount);
	event LockerSet(address oldLocker, address newLocker);
	event GovernanceSet(address oldGov, address newGov);
	event TokenRewardSet(address oldTr, address newTr);
	event TokenDeposited(address token, uint256 amount);
	event ERC20Rescued(address token, uint256 amount);

	/* ========== CONSTRUCTOR ========== */
	constructor(address _tokenReward, address _gauge) {
		tokenReward = _tokenReward;
		gauge = _gauge;
		governance = msg.sender;
	}

	/* ========== MUTATIVE FUNCTIONS ========== */

	/// @notice Notify the reward using an extra token
	/// @param _tokenReward token address to notify
	/// @param _amount amount to notify
	function notifyExtraReward(address _tokenReward, uint256 _amount) external {
		require(msg.sender == governance, "!gov");
		_notifyReward(_tokenReward, _amount);
		_distributeSDT();
	}

	/// @notice Notify the reward using all balance of extra token
	/// @param _tokenReward token address to notify
	function notifyAllExtraReward(address _tokenReward) external {
		require(msg.sender == governance, "!gov");
		uint256 amount = IERC20(_tokenReward).balanceOf(address(this));
		_notifyReward(_tokenReward, amount);
		_distributeSDT();
	}

	function notifyExtraReward(address[] calldata _tokens, uint256[] calldata amounts) external {
		require(msg.sender == governance, "!gov");
		_notifyExtraReward(_tokens, amounts);
		_distributeSDT();
	}

	function _notifyExtraReward(address[] memory _tokens, uint256[] memory amounts) internal {
		uint256 length = _tokens.length;
		for (uint256 i; i < length; ++i) {
			_notifyReward(_tokens[i], amounts[i]);
		}
	}

	function notifyAllExtraReward(address[] calldata _tokens) external {
		require(msg.sender == governance, "!gov");
		_notifyAllExtraReward(_tokens);
		_distributeSDT();
	}

	function _notifyAllExtraReward(address[] memory _tokens) internal {
		uint256 amount;
		uint256 length = _tokens.length;
		for (uint256 i; i < length; ++i) {
			amount = IERC20(_tokens[i]).balanceOf(address(this));
			_notifyReward(_tokens[i], amount);
		}
	}

	function _distributeSDT() internal {
		if (sdtDistributor != address(0)) {
			ISDTDistributor(sdtDistributor).distribute(gauge);
		}
	}

	/// @notice Notify the new reward to the LGV4
	/// @param _tokenReward token to notify
	/// @param _amount amount to notify
	function _notifyReward(address _tokenReward, uint256 _amount) internal {
		require(gauge != address(0), "gauge not set");
		if (_amount == 0) {
			return;
		}
		uint256 balanceBefore = IERC20(_tokenReward).balanceOf(address(this));
		require(balanceBefore >= _amount, "amount not enough");
		if (ILiquidityGauge(gauge).reward_data(_tokenReward).distributor != address(0)) {
			uint256 claimerReward = (_amount * claimerFee) / 10000;
			IERC20(_tokenReward).transfer(msg.sender, claimerReward);
			_amount -= claimerReward;
			IERC20(_tokenReward).approve(gauge, _amount);
			ILiquidityGauge(gauge).deposit_reward_token(_tokenReward, _amount);

			uint256 balanceAfter = IERC20(_tokenReward).balanceOf(address(this));

			require(balanceBefore - balanceAfter == _amount, "wrong amount notified");

			emit RewardNotified(gauge, _tokenReward, _amount);
		}
	}

	/// @notice Deposit token into the accumulator
	/// @param _token token to deposit
	/// @param _amount amount to deposit
	function depositToken(address _token, uint256 _amount) external {
		require(_amount > 0, "set an amount > 0");
		IERC20(_token).safeTransferFrom(msg.sender, address(this), _amount);
		emit TokenDeposited(_token, _amount);
	}

	/// @notice Sets gauge for the accumulator which will receive and distribute the rewards
	/// @dev Can be called only by the governance
	/// @param _gauge gauge address
	function setGauge(address _gauge) external {
		require(msg.sender == governance, "!gov");
		require(_gauge != address(0), "can't be zero address");
		emit GaugeSet(gauge, _gauge);
		gauge = _gauge;
	}

	/// @notice Sets SdtDistributor to distribute from the Accumulator SDT Rewards to Gauge.
	/// @dev Can be called only by the governance
	/// @param _sdtDistributor gauge address
	function setSdtDistributor(address _sdtDistributor) external {
		require(msg.sender == governance, "!gov");
		require(_sdtDistributor != address(0), "can't be zero address");

		emit SdtDistributorUpdated(sdtDistributor, _sdtDistributor);
		sdtDistributor = _sdtDistributor;
	}

	/// @notice Allows the governance to set the new governance
	/// @dev Can be called only by the governance
	/// @param _governance governance address
	function setGovernance(address _governance) external {
		require(msg.sender == governance, "!gov");
		require(_governance != address(0), "can't be zero address");
		emit GovernanceSet(governance, _governance);
		governance = _governance;
	}

	/// @notice Allows the governance to set the locker
	/// @dev Can be called only by the governance
	/// @param _locker locker address
	function setLocker(address _locker) external {
		require(msg.sender == governance, "!gov");
		require(_locker != address(0), "can't be zero address");
		emit LockerSet(locker, _locker);
		locker = _locker;
	}

	/// @notice Allows the governance to set the token reward
	/// @dev Can be called only by the governance
	/// @param _tokenReward token reward address
	function setTokenReward(address _tokenReward) external {
		require(msg.sender == governance, "!gov");
		require(_tokenReward != address(0), "can't be zero address");
		emit TokenRewardSet(tokenReward, _tokenReward);
		tokenReward = _tokenReward;
	}

	function setClaimerFee(uint256 _claimerFee) external {
		require(msg.sender == governance, "!gov");
		claimerFee = _claimerFee;
	}

	/// @notice A function that rescue any ERC20 token
	/// @param _token token address
	/// @param _amount amount to rescue
	/// @param _recipient address to send token rescued
	function rescueERC20(
		address _token,
		uint256 _amount,
		address _recipient
	) external {
		require(msg.sender == governance, "!gov");
		require(_amount > 0, "set an amount > 0");
		require(_recipient != address(0), "can't be zero address");
		IERC20(_token).safeTransfer(_recipient, _amount);
		emit ERC20Rescued(_token, _amount);
	}
}

// File: contracts/accumulator/CurveAccumulator.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.7;

import "./BaseAccumulator.sol";
import "../strategy/CurveStrategy.sol";

/// @title A contract that accumulates 3crv rewards and notifies them to the LGV4
/// @author StakeDAO
contract CurveAccumulator is BaseAccumulator {
	address public constant CRV3 = 0x6c3F90f043a72FA612cbac8115EE7e52BDe6E490;
	address public constant CRV = 0xD533a949740bb3306d119CC777fa900bA034cd52;
	address public strategy = 0x20F1d4Fed24073a9b9d388AfA2735Ac91f079ED6;

	/* ========== CONSTRUCTOR ========== */
	constructor(address _tokenReward, address _gauge) BaseAccumulator(_tokenReward, _gauge) {}

	/* ========== MUTATIVE FUNCTIONS ========== */
	/// @notice Notify a 3crv amount to the LGV4
	/// @param _amount amount to notify after the claim
	function notify(uint256 _amount) external {
		CurveStrategy(strategy).claim3Crv(false);
		_notifyReward(tokenReward, _amount);
		_distributeSDT();
	}

	/// @notice Notify all 3crv accumulator balance to the LGV4
	function notifyAll() external {
		CurveStrategy(strategy).claim3Crv(false);
		uint256 crv3Amount = IERC20(CRV3).balanceOf(address(this));
		uint256 crvAmount = IERC20(CRV).balanceOf(address(this));
		_notifyReward(tokenReward, crv3Amount);
		_notifyReward(CRV, crvAmount);
		_distributeSDT();
	}

	function changeStrategy(address _newStrategy) external {
		require(msg.sender == governance, "!gov");
		strategy = _newStrategy;
	}
}

// File: contracts/external/AccessControlUpgradeable.sol



// SPDX-License-Identifier: GPL-3.0

pragma solidity ^0.8.7;

import "@openzeppelin/contracts-upgradeable/utils/StringsUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";

import "../interfaces/IAccessControl.sol";

/**
 * @dev This contract is fully forked from OpenZeppelin `AccessControlUpgradeable`.
 * The only difference is the removal of the ERC165 implementation as it's not
 * needed in Angle.
 *
 * Contract module that allows children to implement role-based access
 * control mechanisms. This is a lightweight version that doesn't allow enumerating role
 * members except through off-chain means by accessing the contract event logs. Some
 * applications may benefit from on-chain enumerability, for those cases see
 * {AccessControlEnumerable}.
 *
 * Roles are referred to by their `bytes32` identifier. These should be exposed
 * in the external API and be unique. The best way to achieve this is by
 * using `public constant` hash digests:
 *
 * ```
 * bytes32 public constant MY_ROLE = keccak256("MY_ROLE");
 * ```
 *
 * Roles can be used to represent a set of permissions. To restrict access to a
 * function call, use {hasRole}:
 *
 * ```
 * function foo() public {
 *     require(hasRole(MY_ROLE, msg.sender));
 *     ...
 * }
 * ```
 *
 * Roles can be granted and revoked dynamically via the {grantRole} and
 * {revokeRole} functions. Each role has an associated admin role, and only
 * accounts that have a role's admin role can call {grantRole} and {revokeRole}.
 *
 * By default, the admin role for all roles is `DEFAULT_ADMIN_ROLE`, which means
 * that only accounts with this role will be able to grant or revoke other
 * roles. More complex role relationships can be created by using
 * {_setRoleAdmin}.
 *
 * WARNING: The `DEFAULT_ADMIN_ROLE` is also its own admin: it has permission to
 * grant and revoke this role. Extra precautions should be taken to secure
 * accounts that have been granted it.
 */
abstract contract AccessControlUpgradeable is Initializable, IAccessControl {
    function __AccessControl_init() internal initializer {
        __AccessControl_init_unchained();
    }

    function __AccessControl_init_unchained() internal initializer {}

    struct RoleData {
        mapping(address => bool) members;
        bytes32 adminRole;
    }

    mapping(bytes32 => RoleData) private _roles;

    bytes32 public constant DEFAULT_ADMIN_ROLE = 0x00;

    /**
     * @dev Emitted when `newAdminRole` is set as ``role``'s admin role, replacing `previousAdminRole`
     *
     * `DEFAULT_ADMIN_ROLE` is the starting admin for all roles, despite
     * {RoleAdminChanged} not being emitted signaling this.
     *
     * _Available since v3.1._
     */
    event RoleAdminChanged(bytes32 indexed role, bytes32 indexed previousAdminRole, bytes32 indexed newAdminRole);

    /**
     * @dev Emitted when `account` is granted `role`.
     *
     * `sender` is the account that originated the contract call, an admin role
     * bearer except when using {_setupRole}.
     */
    event RoleGranted(bytes32 indexed role, address indexed account, address indexed sender);

    /**
     * @dev Emitted when `account` is revoked `role`.
     *
     * `sender` is the account that originated the contract call:
     *   - if using `revokeRole`, it is the admin role bearer
     *   - if using `renounceRole`, it is the role bearer (i.e. `account`)
     */
    event RoleRevoked(bytes32 indexed role, address indexed account, address indexed sender);

    /**
     * @dev Modifier that checks that an account has a specific role. Reverts
     * with a standardized message including the required role.
     *
     * The format of the revert reason is given by the following regular expression:
     *
     *  /^AccessControl: account (0x[0-9a-f]{20}) is missing role (0x[0-9a-f]{32})$/
     *
     * _Available since v4.1._
     */
    modifier onlyRole(bytes32 role) {
        _checkRole(role, msg.sender);
        _;
    }

    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account) public view override returns (bool) {
        return _roles[role].members[account];
    }

    /**
     * @dev Revert with a standard message if `account` is missing `role`.
     *
     * The format of the revert reason is given by the following regular expression:
     *
     *  /^AccessControl: account (0x[0-9a-f]{20}) is missing role (0x[0-9a-f]{32})$/
     */
    function _checkRole(bytes32 role, address account) internal view {
        if (!hasRole(role, account)) {
            revert(
                string(
                    abi.encodePacked(
                        "AccessControl: account ",
                        StringsUpgradeable.toHexString(uint160(account), 20),
                        " is missing role ",
                        StringsUpgradeable.toHexString(uint256(role), 32)
                    )
                )
            );
        }
    }

    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role) public view override returns (bytes32) {
        return _roles[role].adminRole;
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function grantRole(bytes32 role, address account) external override onlyRole(getRoleAdmin(role)) {
        _grantRole(role, account);
    }

    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function revokeRole(bytes32 role, address account) external override onlyRole(getRoleAdmin(role)) {
        _revokeRole(role, account);
    }

    /**
     * @dev Revokes `role` from the calling account.
     *
     * Roles are often managed via {grantRole} and {revokeRole}: this function's
     * purpose is to provide a mechanism for accounts to lose their privileges
     * if they are compromised (such as when a trusted device is misplaced).
     *
     * If the calling account had been granted `role`, emits a {RoleRevoked}
     * event.
     *
     * Requirements:
     *
     * - the caller must be `account`.
     */
    function renounceRole(bytes32 role, address account) external override {
        require(account == msg.sender, "71");

        _revokeRole(role, account);
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event. Note that unlike {grantRole}, this function doesn't perform any
     * checks on the calling account.
     *
     * [WARNING]
     * ====
     * This function should only be called from the constructor when setting
     * up the initial roles for the system.
     *
     * Using this function in any other way is effectively circumventing the admin
     * system imposed by {AccessControl}.
     * ====
     */
    function _setupRole(bytes32 role, address account) internal {
        _grantRole(role, account);
    }

    /**
     * @dev Sets `adminRole` as ``role``'s admin role.
     *
     * Emits a {RoleAdminChanged} event.
     */
    function _setRoleAdmin(bytes32 role, bytes32 adminRole) internal {
        emit RoleAdminChanged(role, getRoleAdmin(role), adminRole);
        _roles[role].adminRole = adminRole;
    }

    function _grantRole(bytes32 role, address account) internal {
        if (!hasRole(role, account)) {
            _roles[role].members[account] = true;
            emit RoleGranted(role, account, msg.sender);
        }
    }

    function _revokeRole(bytes32 role, address account) internal {
        if (hasRole(role, account)) {
            _roles[role].members[account] = false;
            emit RoleRevoked(role, account, msg.sender);
        }
    }

    uint256[49] private __gap;
}
// File: contracts/interfaces/IAccessControl.sol



// SPDX-License-Identifier: GPL-3.0
pragma solidity 0.8.7;

/// @title IAccessControl
/// @author Forked from OpenZeppelin
/// @notice Interface for `AccessControl` contracts
interface IAccessControl {
    function hasRole(bytes32 role, address account) external view returns (bool);

    function getRoleAdmin(bytes32 role) external view returns (bytes32);

    function grantRole(bytes32 role, address account) external;

    function revokeRole(bytes32 role, address account) external;

    function renounceRole(bytes32 role, address account) external;
}
// File: contracts/interfaces/IGaugeController.sol



// SPDX-License-Identifier: GPL-3.0
pragma solidity 0.8.7;

interface IGaugeController {
    //solhint-disable-next-line
    function gauge_types(address addr) external view returns (int128);

    //solhint-disable-next-line
    function gauge_relative_weight_write(address addr, uint256 timestamp) external returns (uint256);

    //solhint-disable-next-line
    function gauge_relative_weight(address addr) external view returns (uint256);

    //solhint-disable-next-line
    function gauge_relative_weight(address addr, uint256 timestamp) external view returns (uint256);

    //solhint-disable-next-line
    function get_total_weight() external view returns (uint256);

    //solhint-disable-next-line
    function get_gauge_weight(address addr) external view returns (uint256);
}
// File: contracts/interfaces/ILiquidityGauge.sol



// SPDX-License-Identifier: GPL-3.0
pragma solidity 0.8.7;

interface ILiquidityGauge {
	struct Reward {
		address token;
		address distributor;
		uint256 period_finish;
		uint256 rate;
		uint256 last_update;
		uint256 integral;
	}

	// solhint-disable-next-line
	function deposit_reward_token(address _rewardToken, uint256 _amount) external;

	// solhint-disable-next-line
	function claim_rewards_for(address _user, address _recipient) external;

	// // solhint-disable-next-line
	// function claim_rewards_for(address _user) external;

	// solhint-disable-next-line
	function deposit(uint256 _value, address _addr) external;

	// solhint-disable-next-line
	function reward_tokens(uint256 _i) external view returns (address);

	// solhint-disable-next-line
	function reward_data(address _tokenReward) external view returns (Reward memory);

	function balanceOf(address) external returns (uint256);

	function claimable_reward(address _user, address _reward_token) external view returns (uint256);

	function claimable_tokens(address _user) external returns (uint256);

	function user_checkpoint(address _user) external returns (bool);

	function commit_transfer_ownership(address) external;

	function claim_rewards(address) external;
}

// File: contracts/interfaces/ILocker.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.7;

interface ILocker {
	function createLock(uint256, uint256) external;

	function claimAllRewards(address[] calldata _tokens, address _recipient) external;

	function increaseAmount(uint256) external;

	function increaseUnlockTime(uint256) external;

	function release() external;

	function claimRewards(address,address) external;

	function claimFXSRewards(address) external;

	function execute(
		address,
		uint256,
		bytes calldata
	) external returns (bool, bytes memory);

	function setGovernance(address) external;

	function voteGaugeWeight(address, uint256) external;

	function setAngleDepositor(address) external;

	function setFxsDepositor(address) external;
}

// File: contracts/interfaces/IMasterchef.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.7;

interface IMasterchef {
	function deposit(uint256, uint256) external;

	function withdraw(uint256, uint256) external;

	function userInfo(uint256, address) external view returns (uint256, uint256);

	function poolInfo(uint256)
		external
		returns (
			address,
			uint256,
			uint256,
			uint256
		);

	function totalAllocPoint() external view returns (uint256);

	function sdtPerBlock() external view returns (uint256);

	function pendingSdt(uint256, address) external view returns (uint256);
}

// File: contracts/interfaces/IMultiRewards.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.7;

interface IMultiRewards {
	function balanceOf(address) external returns (uint256);

	function stakeFor(address, uint256) external;

	function withdrawFor(address, uint256) external;

	function notifyRewardAmount(address, uint256) external;

	function mintFor(address recipient, uint256 amount) external;

	function burnFrom(address _from, uint256 _amount) external;

	function stakeOf(address account) external view returns (uint256);
}

// File: contracts/interfaces/ISDTDistributor.sol



// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.7;

interface ISDTDistributor {
    function distribute(address gaugeAddr) external;
}

// File: contracts/interfaces/ISdtMiddlemanGauge.sol



// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.7;

interface ISdtMiddlemanGauge {
	function notifyReward(address gauge, uint256 amount) external;
}

// File: contracts/interfaces/IStakingRewards.sol



// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.7;

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

/// @title IStakingRewardsFunctions
/// @author StakeDAO Core Team
/// @notice Interface for the staking rewards contract that interact with the `RewardsDistributor` contract
interface IStakingRewardsFunctions {
    function notifyRewardAmount(uint256 reward) external;

    function recoverERC20(
        address tokenAddress,
        address to,
        uint256 tokenAmount
    ) external;

    function setNewRewardsDistribution(address newRewardsDistribution) external;
}

/// @title IStakingRewards
/// @author StakeDAO Core Team
/// @notice Previous interface with additionnal getters for public variables
interface IStakingRewards is IStakingRewardsFunctions {
    function rewardToken() external view returns (IERC20);
}
// File: contracts/staking/MasterchefMasterToken.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.7;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";

contract MasterchefMasterToken is ERC20, Ownable {
	constructor() ERC20("Masterchef Master Token", "MMT") {
		_mint(msg.sender, 1e18);
	}
}
// File: contracts/staking/SdtDistributorEvents.sol



// SPDX-License-Identifier: GPL-3.0

pragma solidity 0.8.7;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "@openzeppelin/contracts-upgradeable/security/ReentrancyGuardUpgradeable.sol";

import "../interfaces/IGaugeController.sol";
import "../interfaces/ILiquidityGauge.sol";
import "../interfaces/ISdtMiddlemanGauge.sol";
import "../interfaces/IStakingRewards.sol";

import "../interfaces/IMasterchef.sol";
import "./MasterchefMasterToken.sol";

import "../external/AccessControlUpgradeable.sol";

/// @title SdtDistributorEvents
/// @author StakeDAO Core Team
/// @notice All the events used in `SdtDistributor` contract
 abstract contract SdtDistributorEvents {
	event DelegateGaugeUpdated(address indexed _gaugeAddr, address indexed _delegateGauge);
	event DistributionsToggled(bool _distributionsOn);
	event GaugeControllerUpdated(address indexed _controller);
	event GaugeToggled(address indexed gaugeAddr, bool newStatus);
	event InterfaceKnownToggled(address indexed _delegateGauge, bool _isInterfaceKnown);
	event RateUpdated(uint256 _newRate);
	event Recovered(address indexed tokenAddress, address indexed to, uint256 amount);
	event RewardDistributed(address indexed gaugeAddr, uint256 sdtDistributed, uint256 lastMasterchefPull);
	event UpdateMiningParameters(uint256 time, uint256 rate, uint256 supply);
}

// File: contracts/staking/SdtDistributorV2.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.8.7;

import "./SdtDistributorEvents.sol";

/// @title SdtDistributorV2
/// @notice Earn from Masterchef SDT and distribute it to gauges
contract SdtDistributorV2 is ReentrancyGuardUpgradeable, AccessControlUpgradeable, SdtDistributorEvents {
	using SafeERC20 for IERC20;

	////////////////////////////////////////////////////////////////
	/// --- CONSTANTS
	///////////////////////////////////////////////////////////////

	/// @notice Accounting
	uint256 public constant BASE_UNIT = 10_000;

	/// @notice Address of the SDT token given as a reward.
	IERC20 public constant rewardToken = IERC20(0x73968b9a57c6E53d41345FD57a6E6ae27d6CDB2F);

	/// @notice Address of the masterchef.
	IMasterchef public constant masterchef = IMasterchef(0xfEA5E213bbD81A8a94D0E1eDB09dBD7CEab61e1c);

	/// @notice Role for governors only.
	bytes32 public constant GOVERNOR_ROLE = keccak256("GOVERNOR_ROLE");
	/// @notice Role for the guardian
	bytes32 public constant GUARDIAN_ROLE = keccak256("GUARDIAN_ROLE");

	////////////////////////////////////////////////////////////////
	/// --- STORAGE SLOTS
	///////////////////////////////////////////////////////////////

	/// @notice Time between SDT Harvest.
	uint256 public timePeriod;

	/// @notice Address of the token that will be deposited in masterchef.
	IERC20 public masterchefToken;

	/// @notice Address of the `GaugeController` contract.
	IGaugeController public controller;

	/// @notice Address responsible for pulling rewards of type >= 2 gauges and distributing it to the
	/// associated contracts if there is not already an address delegated for this specific contract.
	address public delegateGauge;

	/// @notice Whether SDT distribution through this contract is on or no.
	bool public distributionsOn;

	/// @notice Maps the address of a type >= 2 gauge to a delegate address responsible
	/// for giving rewards to the actual gauge.
	mapping(address => address) public delegateGauges;

	/// @notice Maps the address of a gauge to whether it was killed or not
	/// A gauge killed in this contract cannot receive any rewards.
	mapping(address => bool) public killedGauges;

	/// @notice Maps the address of a gauge delegate to whether this delegate supports the `notifyReward` interface
	/// and is therefore built for automation.
	mapping(address => bool) public isInterfaceKnown;

	/// @notice Masterchef PID
	uint256 public masterchefPID;

	/// @notice Timestamp of the last pull from masterchef.
	uint256 public lastMasterchefPull;

	/// @notice Maps the timestamp of pull action to the amount of SDT that pulled.
	mapping(uint256 => uint256) public pulls; // day => SDT amount

	/// @notice Maps the timestamp of last pull to the gauge addresses then keeps the data if particular gauge paid in the last pull.
	mapping(uint256 => mapping(address => bool)) public isGaugePaid;

	/// @notice Incentive for caller.
	uint256 public claimerFee;

	/// @notice Number of days to go through for past distributing.
	uint256 public lookPastDays;

	////////////////////////////////////////////////////////////////
	/// --- INITIALIZATION LOGIC
	///////////////////////////////////////////////////////////////

	/// @notice Initialize function
	/// @param _controller gauge controller to manage votes
	/// @param _governor governor address
	/// @param _guardian guardian address
	/// @param _delegateGauge delegate gauge address
	function initialize(
		address _controller,
		address _governor,
		address _guardian,
		address _delegateGauge
	) external initializer {
		require(_controller != address(0) && _guardian != address(0) && _governor != address(0), "0");

		controller = IGaugeController(_controller);
		delegateGauge = _delegateGauge;

		masterchefToken = IERC20(address(new MasterchefMasterToken()));
		distributionsOn = false;

		timePeriod = 3600 * 24; // One day in seconds
		lookPastDays = 45; // for past 45 days check

		_setRoleAdmin(GOVERNOR_ROLE, GOVERNOR_ROLE);
		_setRoleAdmin(GUARDIAN_ROLE, GOVERNOR_ROLE);

		_setupRole(GUARDIAN_ROLE, _guardian);
		_setupRole(GOVERNOR_ROLE, _governor);
		_setupRole(GUARDIAN_ROLE, _governor);
	}

	/// @custom:oz-upgrades-unsafe-allow constructor
	constructor() initializer {}

	/// @notice Initialize the masterchef depositing the master token
	/// @param _pid pool id to deposit the token
	function initializeMasterchef(uint256 _pid) external onlyRole(GOVERNOR_ROLE) {
		masterchefPID = _pid;
		masterchefToken.approve(address(masterchef), 1e18);
		masterchef.deposit(_pid, 1e18);
	}

	////////////////////////////////////////////////////////////////
	/// --- DISTRIBUTION LOGIC
	///////////////////////////////////////////////////////////////

	/// @notice Distribute SDT to Gauges
	/// @param gaugeAddr Address of the gauge to distribute.
	function distribute(address gaugeAddr) external nonReentrant {
		_distribute(gaugeAddr);
	}

	/// @notice Distribute SDT to Multiple Gauges
	/// @param gaugeAddr Array of addresses of the gauge to distribute.
	function distributeMulti(address[] calldata gaugeAddr) public nonReentrant {
		uint256 length = gaugeAddr.length;
		for (uint256 i; i < length; i++) {
			_distribute(gaugeAddr[i]);
		}
	}

	/// @notice Internal implementation of distribute logic.
	/// @param gaugeAddr Address of the gauge to distribute rewards to
	function _distribute(address gaugeAddr) internal {
		require(distributionsOn, "not allowed");
		(bool success, bytes memory result) = address(controller).call(
			abi.encodeWithSignature("gauge_types(address)", gaugeAddr)
		);
		if (!success || killedGauges[gaugeAddr]) {
			return;
		}
		int128 gaugeType = abi.decode(result, (int128));

		// Rounded to beginning of the day -> 00:00 UTC
		uint256 roundedTimestamp = (block.timestamp / 1 days) * 1 days;

		uint256 totalDistribute;

		if (block.timestamp > lastMasterchefPull + timePeriod) {
			uint256 sdtBefore = rewardToken.balanceOf(address(this));
			_pullSDT();
			pulls[roundedTimestamp] = rewardToken.balanceOf(address(this)) - sdtBefore;
			lastMasterchefPull = roundedTimestamp;
		}
		// check past n days
		for (uint256 i; i < lookPastDays; i++) {
			uint256 currentTimestamp = roundedTimestamp - (i * 86_400);

			if (pulls[currentTimestamp] > 0) {
				bool isPaid = isGaugePaid[currentTimestamp][gaugeAddr];
				if (isPaid) {
					break;
				}

				// Retrieve the amount pulled from Masterchef at the given timestamp.
				uint256 sdtBalance = pulls[currentTimestamp];
				uint256 gaugeRelativeWeight;

				if (i == 0) {
					// Makes sure the weight is checkpointed. Also returns the weight.
					gaugeRelativeWeight = controller.gauge_relative_weight_write(gaugeAddr, currentTimestamp);
				} else {
					gaugeRelativeWeight = controller.gauge_relative_weight(gaugeAddr, currentTimestamp);
				}

				uint256 sdtDistributed = (sdtBalance * gaugeRelativeWeight) / 1e18;
				totalDistribute += sdtDistributed;
				isGaugePaid[currentTimestamp][gaugeAddr] = true;
			}
		}
		if (totalDistribute > 0) {
			if (gaugeType == 1) {
				rewardToken.safeTransfer(gaugeAddr, totalDistribute);
				IStakingRewards(gaugeAddr).notifyRewardAmount(totalDistribute);
			} else if (gaugeType >= 2) {
				// If it is defined, we use the specific delegate attached to the gauge
				address delegate = delegateGauges[gaugeAddr];
				if (delegate == address(0)) {
					// If not, we check if a delegate common to all gauges with type >= 2 can be used
					delegate = delegateGauge;
				}
				if (delegate != address(0)) {
					// In the case where the gauge has a delegate (specific or not), then rewards are transferred to this gauge
					rewardToken.safeTransfer(delegate, totalDistribute);
					// If this delegate supports a specific interface, then rewards sent are notified through this
					// interface
					if (isInterfaceKnown[delegate]) {
						ISdtMiddlemanGauge(delegate).notifyReward(gaugeAddr, totalDistribute);
					}
				} else {
					rewardToken.safeTransfer(gaugeAddr, totalDistribute);
				}
			} else {
				ILiquidityGauge(gaugeAddr).deposit_reward_token(address(rewardToken), totalDistribute);
			}

			emit RewardDistributed(gaugeAddr, totalDistribute, lastMasterchefPull);
		}
	}

	/// @notice Internal function to pull SDT from the MasterChef
	function _pullSDT() internal {
		masterchef.withdraw(masterchefPID, 0);
	}

	////////////////////////////////////////////////////////////////
	/// --- RESTRICTIVE FUNCTIONS
	///////////////////////////////////////////////////////////////

	/// @notice Sets the distribution state (on/off)
	/// @param _state new distribution state
	function setDistribution(bool _state) external onlyRole(GOVERNOR_ROLE) {
		distributionsOn = _state;
	}

	/// @notice Sets a new gauge controller
	/// @param _controller Address of the new gauge controller
	function setGaugeController(address _controller) external onlyRole(GOVERNOR_ROLE) {
		require(_controller != address(0), "0");
		controller = IGaugeController(_controller);
		emit GaugeControllerUpdated(_controller);
	}

	/// @notice Sets a new delegate gauge for pulling rewards of a type >= 2 gauges or of all type >= 2 gauges
	/// @param gaugeAddr Gauge to change the delegate of
	/// @param _delegateGauge Address of the new gauge delegate related to `gaugeAddr`
	/// @param toggleInterface Whether we should toggle the fact that the `_delegateGauge` is built for automation or not
	/// @dev This function can be used to remove delegating or introduce the pulling of rewards to a given address
	/// @dev If `gaugeAddr` is the zero address, this function updates the delegate gauge common to all gauges with type >= 2
	/// @dev The `toggleInterface` parameter has been added for convenience to save one transaction when adding a gauge delegate
	/// which supports the `notifyReward` interface
	function setDelegateGauge(
		address gaugeAddr,
		address _delegateGauge,
		bool toggleInterface
	) external onlyRole(GOVERNOR_ROLE) {
		if (gaugeAddr != address(0)) {
			delegateGauges[gaugeAddr] = _delegateGauge;
		} else {
			delegateGauge = _delegateGauge;
		}
		emit DelegateGaugeUpdated(gaugeAddr, _delegateGauge);

		if (toggleInterface) {
			_toggleInterfaceKnown(_delegateGauge);
		}
	}

	/// @notice Toggles the status of a gauge to either killed or unkilled
	/// @param gaugeAddr Gauge to toggle the status of
	/// @dev It is impossible to kill a gauge in the `GaugeController` contract, for this reason killing of gauges
	/// takes place in the `SdtDistributor` contract
	/// @dev This means that people could vote for a gauge in the gauge controller contract but that rewards are not going
	/// to be distributed to it in the end: people would need to remove their weights on the gauge killed to end the diminution
	/// in rewards
	/// @dev In the case of a gauge being killed, this function resets the timestamps at which this gauge has been approved and
	/// disapproves the gauge to spend the token
	/// @dev It should be cautiously called by governance as it could result in less SDT overall rewards than initially planned
	/// if people do not remove their voting weights to the killed gauge
	function toggleGauge(address gaugeAddr) external onlyRole(GOVERNOR_ROLE) {
		bool gaugeKilledMem = killedGauges[gaugeAddr];
		if (!gaugeKilledMem) {
			rewardToken.safeApprove(gaugeAddr, 0);
		}
		killedGauges[gaugeAddr] = !gaugeKilledMem;
		emit GaugeToggled(gaugeAddr, !gaugeKilledMem);
	}

	/// @notice Notifies that the interface of a gauge delegate is known or has changed
	/// @param _delegateGauge Address of the gauge to change
	/// @dev Gauge delegates that are built for automation should be toggled
	function toggleInterfaceKnown(address _delegateGauge) external onlyRole(GUARDIAN_ROLE) {
		_toggleInterfaceKnown(_delegateGauge);
	}

	/// @notice Toggles the fact that a gauge delegate can be used for automation or not and therefore supports
	/// the `notifyReward` interface
	/// @param _delegateGauge Address of the gauge to change
	function _toggleInterfaceKnown(address _delegateGauge) internal {
		bool isInterfaceKnownMem = isInterfaceKnown[_delegateGauge];
		isInterfaceKnown[_delegateGauge] = !isInterfaceKnownMem;
		emit InterfaceKnownToggled(_delegateGauge, !isInterfaceKnownMem);
	}

	/// @notice Gives max approvement to the gauge
	/// @param gaugeAddr Address of the gauge
	function approveGauge(address gaugeAddr) external onlyRole(GOVERNOR_ROLE) {
		rewardToken.safeApprove(gaugeAddr, type(uint256).max);
	}

	/// @notice Set the time period to pull SDT from Masterchef
	/// @param _timePeriod new timePeriod value in seconds
	function setTimePeriod(uint256 _timePeriod) external onlyRole(GOVERNOR_ROLE) {
		require(_timePeriod >= 1 days, "TOO_LOW");
		timePeriod = _timePeriod;
	}

	function setClaimerFee(uint256 _newFee) external onlyRole(GOVERNOR_ROLE) {
		require(_newFee <= BASE_UNIT, "TOO_HIGH");
		claimerFee = _newFee;
	}

	/// @notice Set the how many days we should look back for reward distribution
	/// @param _newLookPastDays new value for how many days we should look back
	function setLookPastDays(uint256 _newLookPastDays) external onlyRole(GOVERNOR_ROLE) {
		lookPastDays = _newLookPastDays;
	}

	/// @notice Withdraws ERC20 tokens that could accrue on this contract
	/// @param tokenAddress Address of the ERC20 token to withdraw
	/// @param to Address to transfer to
	/// @param amount Amount to transfer
	/// @dev Added to support recovering LP Rewards and other mistaken tokens
	/// from other systems to be distributed to holders
	/// @dev This function could also be used to recover SDT tokens in case the rate got smaller
	function recoverERC20(
		address tokenAddress,
		address to,
		uint256 amount
	) external onlyRole(GOVERNOR_ROLE) {
		IERC20(tokenAddress).safeTransfer(to, amount);
		emit Recovered(tokenAddress, to, amount);
	}
}

// File: contracts/strategy/BaseStrategy.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.7;
import "../interfaces/ILocker.sol";

contract BaseStrategy {
	/* ========== STATE VARIABLES ========== */
	ILocker public locker;
	address public governance;
	address public rewardsReceiver;
	address public veSDTFeeProxy;
	address public vaultGaugeFactory;
	uint256 public constant BASE_FEE = 10_000;
	mapping(address => address) public gauges;
	mapping(address => bool) public vaults;
	mapping(address => uint256) public perfFee;
	mapping(address => address) public multiGauges;
	mapping(address => uint256) public accumulatorFee; // gauge -> fee
	mapping(address => uint256) public claimerRewardFee; // gauge -> fee
	mapping(address => uint256) public veSDTFee; // gauge -> fee

	/* ========== EVENTS ========== */
	event Deposited(address _gauge, address _token, uint256 _amount);
	event Withdrawn(address _gauge, address _token, uint256 _amount);
	event Claimed(address _gauge, address _token, uint256 _amount);
	event RewardReceiverSet(address _gauge, address _receiver);
	event VaultToggled(address _vault, bool _newState);
	event GaugeSet(address _gauge, address _token);

	/* ========== MODIFIERS ========== */
	modifier onlyGovernance() {
		require(msg.sender == governance, "!governance");
		_;
	}
	modifier onlyApprovedVault() {
		require(vaults[msg.sender], "!approved vault");
		_;
	}
	modifier onlyGovernanceOrFactory() {
		require(msg.sender == governance || msg.sender == vaultGaugeFactory, "!governance && !factory");
		_;
	}

	/* ========== CONSTRUCTOR ========== */
	constructor(
		ILocker _locker,
		address _governance,
		address _receiver
	) {
		locker = _locker;
		governance = _governance;
		rewardsReceiver = _receiver;
	}

	/* ========== MUTATIVE FUNCTIONS ========== */
	function deposit(address _token, uint256 _amount) external virtual onlyApprovedVault {}

	function withdraw(address _token, uint256 _amount) external virtual onlyApprovedVault {}

	function claim(address _gauge) external virtual {}

	function toggleVault(address _vault) external virtual onlyGovernanceOrFactory {}

	function setGauge(address _token, address _gauge) external virtual onlyGovernanceOrFactory {}

	function setMultiGauge(address _gauge, address _multiGauge) external virtual onlyGovernanceOrFactory {}
}

// File: contracts/strategy/CurveStrategy.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.7;
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "./BaseStrategy.sol";
import "../accumulator/CurveAccumulator.sol";
import "../interfaces/ILiquidityGauge.sol";
import "../interfaces/IMultiRewards.sol";
import "../staking/SdtDistributorV2.sol";

contract CurveStrategy is BaseStrategy {
	using SafeERC20 for IERC20;

	CurveAccumulator public accumulator;
	address public sdtDistributor;
	address public constant CRV_FEE_D = 0xA464e6DCda8AC41e03616F95f4BC98a13b8922Dc;
	address public constant CRV3 = 0x6c3F90f043a72FA612cbac8115EE7e52BDe6E490;
	address public constant CRV_MINTER = 0xd061D61a4d941c39E5453435B6345Dc261C2fcE0;
	address public constant CRV = 0xD533a949740bb3306d119CC777fa900bA034cd52;
	mapping (address => uint256) public lGaugeType;

	struct ClaimerReward {
		address rewardToken;
		uint256 amount;
	}
	enum MANAGEFEE {
		PERFFEE,
		VESDTFEE,
		ACCUMULATORFEE,
		CLAIMERREWARD
	}

	event Crv3Claimed(uint256 amount, bool notified);

	/* ========== CONSTRUCTOR ========== */
	constructor(
		ILocker _locker,
		address _governance,
		address _receiver,
		CurveAccumulator _accumulator,
		address _veSDTFeeProxy,
		address _sdtDistributor
	) BaseStrategy(_locker, _governance, _receiver) {
		accumulator = _accumulator;
		veSDTFeeProxy = _veSDTFeeProxy;
		sdtDistributor = _sdtDistributor;
	}

	/* ========== MUTATIVE FUNCTIONS ========== */
	/// @notice function to deposit into a gauge
	/// @param _token token address
	/// @param _amount amount to deposit
	function deposit(address _token, uint256 _amount) external override onlyApprovedVault {
		IERC20(_token).transferFrom(msg.sender, address(locker), _amount);
		address gauge = gauges[_token];
		require(gauge != address(0), "!gauge");
		locker.execute(_token, 0, abi.encodeWithSignature("approve(address,uint256)", gauge, 0));
		locker.execute(_token, 0, abi.encodeWithSignature("approve(address,uint256)", gauge, _amount));

		(bool success, ) = locker.execute(gauge, 0, abi.encodeWithSignature("deposit(uint256)", _amount));
		require(success, "Deposit failed!");
		emit Deposited(gauge, _token, _amount);
	}

	/// @notice function to withdraw from a gauge
	/// @param _token token address
	/// @param _amount amount to withdraw
	function withdraw(address _token, uint256 _amount) external override onlyApprovedVault {
		uint256 _before = IERC20(_token).balanceOf(address(locker));
		address gauge = gauges[_token];
		require(gauge != address(0), "!gauge");
		(bool success, ) = locker.execute(gauge, 0, abi.encodeWithSignature("withdraw(uint256)", _amount));
		require(success, "Transfer failed!");
		uint256 _after = IERC20(_token).balanceOf(address(locker));

		uint256 _net = _after - _before;
		(success, ) = locker.execute(_token, 0, abi.encodeWithSignature("transfer(address,uint256)", msg.sender, _net));
		require(success, "Transfer failed!");
		emit Withdrawn(gauge, _token, _amount);
	}

	/// @notice function to send funds into the related accumulator
	/// @param _token token address
	/// @param _amount amount to send
	function sendToAccumulator(address _token, uint256 _amount) external onlyGovernance {
		IERC20(_token).approve(address(accumulator), _amount);
		accumulator.depositToken(_token, _amount);
	}

	/// @notice function to claim the reward
	/// @param _token token address
	function claim(address _token) external override {
		address gauge = gauges[_token];
		require(gauge != address(0), "!gauge");

		uint256 crvBeforeClaim = IERC20(CRV).balanceOf(address(locker));

		// Claim CRV
		// within the mint() it calls the user checkpoint
		(bool success, ) = locker.execute(
			CRV_MINTER,
			0,
			abi.encodeWithSignature("mint(address)", gauge)
		);	
		require(success, "CRV mint failed!");

		uint256 crvMinted = IERC20(CRV).balanceOf(address(locker)) - crvBeforeClaim;
		
		// Send CRV here
		(success, ) = locker.execute(
			CRV,
			0,
			abi.encodeWithSignature("transfer(address,uint256)", address(this), crvMinted)
		);
		require(success, "CRV transfer failed!");

		// Distribute CRV
		uint256 crvNetRewards = sendFee(gauge, CRV, crvMinted);
		IERC20(CRV).approve(multiGauges[gauge], crvNetRewards);
		ILiquidityGauge(multiGauges[gauge]).deposit_reward_token(CRV, crvNetRewards);
		emit Claimed(gauge, CRV, crvMinted);

		// Distribute SDT to the related gauge
		SdtDistributorV2(sdtDistributor).distribute(multiGauges[gauge]);

		// Claim rewards only for lg type 0 and if there is at least one reward token added
		if(lGaugeType[gauge] == 0 && ILiquidityGauge(gauge).reward_tokens(0) != address(0)) {
			(success, ) = locker.execute(
				gauge, 0, abi.encodeWithSignature("claim_rewards(address,address)", address(locker), address(this))
			);
			if (!success) {
				// Claim on behalf of locker
				ILiquidityGauge(gauge).claim_rewards(address(locker));
			}
			address rewardToken;
			uint256 rewardsBalance;
			for (uint8 i = 0; i < 8; i++) {
				rewardToken = ILiquidityGauge(gauge).reward_tokens(i);
				if (rewardToken == address(0)) {
					break;
				}
				if (success) {
					rewardsBalance = IERC20(rewardToken).balanceOf(address(this));
				} else {
					rewardsBalance = IERC20(rewardToken).balanceOf(address(locker));
					(success, ) = locker.execute(
					rewardToken, 0, abi.encodeWithSignature("transfer(address,uint256)", address(this), rewardsBalance)
					);
					require(success, "Transfer failed");
				}
				IERC20(rewardToken).approve(multiGauges[gauge], rewardsBalance);
				ILiquidityGauge(multiGauges[gauge]).deposit_reward_token(rewardToken, rewardsBalance);
				emit Claimed(gauge, rewardToken, rewardsBalance);
			}	
		}
	}

	function sendFee(address _gauge, address _rewardToken, uint256 _rewardsBalance) internal returns(uint256) {
		// calculate the amount for each fee recipient
		uint256 multisigFee = (_rewardsBalance * perfFee[_gauge]) / BASE_FEE;
		uint256 accumulatorPart = (_rewardsBalance * accumulatorFee[_gauge]) / BASE_FEE;
		uint256 veSDTPart = (_rewardsBalance * veSDTFee[_gauge]) / BASE_FEE;
		uint256 claimerPart = (_rewardsBalance * claimerRewardFee[_gauge]) / BASE_FEE;
		// send 
		IERC20(_rewardToken).approve(address(accumulator), accumulatorPart);
		accumulator.depositToken(_rewardToken, accumulatorPart);
		IERC20(_rewardToken).transfer(rewardsReceiver, multisigFee);
		IERC20(_rewardToken).transfer(veSDTFeeProxy, veSDTPart);
		IERC20(_rewardToken).transfer(msg.sender, claimerPart);
		return _rewardsBalance - multisigFee - accumulatorPart - veSDTPart - claimerPart;
	}

	/// @notice function to claim 3crv every week from the curve Fee Distributor
	/// @param _notify choose if claim or claim and notify the amount to the related gauge
	function claim3Crv(bool _notify) external {
		// Claim 3crv from the curve fee Distributor
		// It will send 3crv to the crv locker
		bool success;
		(success, ) = locker.execute(CRV_FEE_D, 0, abi.encodeWithSignature("claim()"));
		require(success, "3crv claim failed");
		// Send 3crv from the locker to the accumulator
		uint256 amountToSend = IERC20(CRV3).balanceOf(address(locker));
		require(amountToSend > 0, "nothing claimed");
		(success, ) = locker.execute(
			CRV3,
			0,
			abi.encodeWithSignature("transfer(address,uint256)", address(accumulator), amountToSend)
		);
		require(success, "3crv transfer failed");
		if (_notify) {
			accumulator.notifyAll();
		}
		emit Crv3Claimed(amountToSend, _notify);
	}

	/// @notice function to toggle a vault
	/// @param _vault vault address
	function toggleVault(address _vault) external override onlyGovernanceOrFactory {
		require(_vault != address(0), "zero address");
		vaults[_vault] = !vaults[_vault];
		emit VaultToggled(_vault, vaults[_vault]);
	}
	
	/// @notice function to set a gauge type
	/// @param _gauge gauge address
	/// @param _gaugeType type of gauge
	function setLGtype(address _gauge, uint256 _gaugeType) external onlyGovernanceOrFactory {
		lGaugeType[_gauge] = _gaugeType;
	}

	/// @notice function to set a new gauge
	/// It permits to set it as  address(0), for disabling it
	/// in case of migration
	/// @param _token token address
	/// @param _gauge gauge address
	function setGauge(address _token, address _gauge) external override onlyGovernanceOrFactory {
		require(_token != address(0), "zero address");
		// Set new gauge
		gauges[_token] = _gauge;
		emit GaugeSet(_gauge, _token);
	}

	/// @notice function to migrate any LP to another strategy contract (hard migration)
	/// @param _token token address
	function migrateLP(address _token) external onlyApprovedVault {
		require(gauges[_token] != address(0), "not existent gauge");
		migrate(_token);
	}

	/// @notice function to migrate any LP, it sends them to the vault
	/// @param _token token address
	function migrate(address _token) internal {
		address gauge = gauges[_token];
		uint256 amount = IERC20(gauge).balanceOf(address(locker));
		// Withdraw LPs from the old gauge
		(bool success, ) = locker.execute(gauge, 0, abi.encodeWithSignature("withdraw(uint256)", amount));
		require(success, "Withdraw failed!");

		// Transfer LPs to the approved vault
		(success, ) = locker.execute(_token, 0, abi.encodeWithSignature("transfer(address,uint256)", msg.sender, amount));
		require(success, "Transfer failed!");
	}

	/// @notice function to set a multi gauge
	/// @param _gauge gauge address
	/// @param _multiGauge multi gauge address
	function setMultiGauge(address _gauge, address _multiGauge) external override onlyGovernanceOrFactory {
		require(_gauge != address(0), "zero address");
		require(_multiGauge != address(0), "zero address");
		multiGauges[_gauge] = _multiGauge;
	}

	/// @notice function to set a new veSDTProxy
	/// @param _newVeSDTProxy veSdtProxy address
	function setVeSDTProxy(address _newVeSDTProxy) external onlyGovernance {
		require(_newVeSDTProxy != address(0), "zero address");
		veSDTFeeProxy = _newVeSDTProxy;
	}

	/// @notice function to set a new accumulator
	/// @param _newAccumulator accumulator address
	function setAccumulator(address _newAccumulator) external onlyGovernance {
		require(_newAccumulator != address(0), "zero address");
		accumulator = CurveAccumulator(_newAccumulator);
	}

	/// @notice function to set a new reward receiver
	/// @param _newRewardsReceiver reward receiver address
	function setRewardsReceiver(address _newRewardsReceiver) external onlyGovernance {
		require(_newRewardsReceiver != address(0), "zero address");
		rewardsReceiver = _newRewardsReceiver;
	}

	/// @notice function to set a new governance address
	/// @param _newGovernance governance address
	function setGovernance(address _newGovernance) external onlyGovernance {
		require(_newGovernance != address(0), "zero address");
		governance = _newGovernance;
	}

	function setVaultGaugeFactory(address _newVaultGaugeFactory) external onlyGovernance {
		require(_newVaultGaugeFactory != address(0), "zero address");
		vaultGaugeFactory = _newVaultGaugeFactory;
	}

	/// @notice function to set new fees
	/// @param _manageFee manageFee
	/// @param _gauge gauge address
	/// @param _newFee new fee to set
	function manageFee(
		MANAGEFEE _manageFee,
		address _gauge,
		uint256 _newFee
	) external onlyGovernanceOrFactory {
		require(_gauge != address(0), "zero address");
		if (_manageFee == MANAGEFEE.PERFFEE) {
			// 0
			perfFee[_gauge] = _newFee;
		} else if (_manageFee == MANAGEFEE.VESDTFEE) {
			// 1
			veSDTFee[_gauge] = _newFee;
		} else if (_manageFee == MANAGEFEE.ACCUMULATORFEE) {
			//2
			accumulatorFee[_gauge] = _newFee;
		} else if (_manageFee == MANAGEFEE.CLAIMERREWARD) {
			// 3
			claimerRewardFee[_gauge] = _newFee;
		}
		require(
			perfFee[_gauge] + 
			veSDTFee[_gauge] + 
			accumulatorFee[_gauge] + 
			claimerRewardFee[_gauge] 
			<= BASE_FEE, "fee to high"
		);
	}

	/// @notice execute a function
	/// @param _to Address to sent the value to
	/// @param _value Value to be sent
	/// @param _data Call function data
	function execute(
		address _to,
		uint256 _value,
		bytes calldata _data
	) external onlyGovernance returns (bool, bytes memory) {
		(bool success, bytes memory result) = _to.call{ value: _value }(_data);
		return (success, result);
	}
}