// SPDX-License-Identifier: MIT
pragma solidity 0.8.7;

// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);

    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `from` to `to` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) external returns (bool);
}

// OpenZeppelin Contracts v4.4.1 (token/ERC20/utils/SafeERC20.sol)

// OpenZeppelin Contracts (last updated v4.5.0) (utils/Address.sol)

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using Address for address;

    function safeTransfer(
        IERC20 token,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(
        IERC20 token,
        address from,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender) + value;
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            uint256 newAllowance = oldAllowance - value;
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
        }
    }

    /**
     * @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");
        }
    }
}

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;

	function setYieldDistributor(address) external;

	function setGaugeController(address) external;

	function setAccumulator(address _accumulator) external;

}

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;

	function add_reward(address, address) external;
}

interface ISDTDistributor {
	function distribute(address gaugeAddr) external;
}

/// @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 amountNotified, uint256 claimerFee);
	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(this)) {
			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 + claimerReward, "wrong amount notified");

			emit RewardNotified(gauge, _tokenReward, _amount, claimerReward);
		}
	}

	/// @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);
	}
}

/// @title A contract that accumulates BPT rewards and notifies them to the LGV4
/// @author StakeDAO
contract BlackpoolAccumulator is BaseAccumulator {
	uint256 public lockerFee; // in 10000

	address public feeReceiver;

	/* ========== CONSTRUCTOR ========== */
	constructor(address _tokenReward, address _gauge) BaseAccumulator(_tokenReward, _gauge) {}

	/* ========== MUTATIVE FUNCTIONS ========== */
	/// @notice Claims rewards from the locker and notify an amount to the LGV4
	/// @param _amount amount to notify after the claim
	function claimAndNotify(uint256 _amount) external {
		require(locker != address(0), "locker not set");
		ILocker(locker).claimRewards(tokenReward, address(this));
		uint256 fee = (_amount * lockerFee) / 10000;
		if (fee > 0) IERC20(tokenReward).transfer(feeReceiver, fee);
		_notifyReward(tokenReward, _amount - fee);
		_distributeSDT();
	}

	/// @notice Claims rewards from the locker and notify all to the LGV4
	function claimAndNotifyAll() external {
		require(locker != address(0), "locker not set");
		ILocker(locker).claimRewards(tokenReward, address(this));
		uint256 amount = IERC20(tokenReward).balanceOf(address(this));
		uint256 fee = (amount * lockerFee) / 10000;
		if (fee > 0) IERC20(tokenReward).transfer(feeReceiver, fee);
		_notifyReward(tokenReward, amount - fee);
		_distributeSDT();
	}

	/// @notice Set new Fee receiver
	function setFeeReceiver(address _feeReceiver) external {
		require(msg.sender == governance, "!gov");
		require(_feeReceiver != address(0), "!address zero");
		feeReceiver = _feeReceiver;
	}

	/// @notice Set fee percentage
	function setLockerFee(uint256 _lockerFee) external {
		require(msg.sender == governance, "!gov");
		require(lockerFee <= 10000, "!>10000");
		lockerFee = _lockerFee;
	}
}