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/// SPDX-License-Identifier: GPL-3.0-or-later
pragma solidity ^0.8.0;

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

import "../library/AddArrayLib.sol";

import "../interfaces/ITradeExecutor.sol";
import "../interfaces/IVault.sol";

/// @title vault (Brahma Vault)
/// @author 0xAd1 and Bapireddy
/// @notice Minimal vault contract to support trades across different protocols.
contract Vault is IVault, ERC20, ReentrancyGuard {
    using AddrArrayLib for AddrArrayLib.Addresses;
    using SafeERC20 for IERC20;
    /*///////////////////////////////////////////////////////////////
                                 CONSTANTS
    //////////////////////////////////////////////////////////////*/
    /// @notice The maximum number of blocks for latest update to be valid.
    /// @dev Needed for processing deposits/withdrawals.
    uint256 constant BLOCK_LIMIT = 50;
    /// @dev minimum balance used to check when executor is removed.
    uint256 constant DUST_LIMIT = 10**6;
    /// @dev The max basis points used as normalizing factor.
    uint256 constant MAX_BPS = 10000;
    /*///////////////////////////////////////////////////////////////
                                IMMUTABLES
    //////////////////////////////////////////////////////////////*/
    /// @notice The underlying token the vault accepts.
    address public immutable override wantToken;
    uint8 private immutable tokenDecimals;

    /*///////////////////////////////////////////////////////////////
                            MUTABLE ACCESS MODFIERS
    //////////////////////////////////////////////////////////////*/
    /// @notice boolean for enabling deposit/withdraw solely via batcher.
    bool public batcherOnlyDeposit;

    /// @notice boolean for enabling emergency mode to halt new withdrawal/deposits into vault.
    bool public emergencyMode;

    // @notice address of batcher used for batching user deposits/withdrawals.
    address public batcher;
    /// @notice keeper address to move funds between executors.
    address public override keeper;
    /// @notice Governance address to add/remove  executors.
    address public override governance;
    address public pendingGovernance;

    /// @notice Creates a new Vault that accepts a specific underlying token.
    /// @param _wantToken The ERC20 compliant token the vault should accept.
    /// @param _name The name of the vault token.
    /// @param _symbol The symbol of the vault token.
    /// @param _keeper The address of the keeper to move funds between executors.
    /// @param _governance The address of the governance to perform governance functions.
    constructor(
        string memory _name,
        string memory _symbol,
        address _wantToken,
        address _keeper,
        address _governance
    ) ERC20(_name, _symbol) {
        tokenDecimals = IERC20Metadata(_wantToken).decimals();
        wantToken = _wantToken;
        keeper = _keeper;
        governance = _governance;
        // to prevent any front running deposits
        batcherOnlyDeposit = true;
    }

    function decimals() public view override returns (uint8) {
        return tokenDecimals;
    }

    /*///////////////////////////////////////////////////////////////
                       USER DEPOSIT/WITHDRAWAL LOGIC
    //////////////////////////////////////////////////////////////*/
    /// @notice Initiates a deposit of want tokens to the vault.
    /// @param amountIn The amount of want tokens to deposit.
    /// @param receiver The address to receive vault tokens.
    function deposit(uint256 amountIn, address receiver)
        public
        override
        nonReentrant
        ensureFeesAreCollected
        returns (uint256 shares)
    {
        /// checks for only batcher deposit
        onlyBatcher();
        isValidAddress(receiver);
        require(amountIn > 0, "ZERO_AMOUNT");
        // calculate the shares based on the amount.
        shares = totalSupply() > 0
            ? (totalSupply() * amountIn) / totalVaultFunds()
            : amountIn;
        IERC20(wantToken).safeTransferFrom(msg.sender, address(this), amountIn);
        _mint(receiver, shares);
    }

    /// @notice Initiates a withdrawal of vault tokens to the user.
    /// @param sharesIn The amount of vault tokens to withdraw.
    /// @param receiver The address to receive the vault tokens.
    function withdraw(uint256 sharesIn, address receiver)
        public
        override
        nonReentrant
        ensureFeesAreCollected
        returns (uint256 amountOut)
    {
        /// checks for only batcher withdrawal
        onlyBatcher();
        isValidAddress(receiver);
        require(sharesIn > 0, "ZERO_SHARES");
        // calculate the amount based on the shares.
        amountOut = (sharesIn * totalVaultFunds()) / totalSupply();
        // burn shares of msg.sender
        _burn(msg.sender, sharesIn);
        IERC20(wantToken).safeTransfer(receiver, amountOut);
    }

    /// @notice Calculates the total amount of underlying tokens the vault holds.
    /// @return The total amount of underlying tokens the vault holds.
    function totalVaultFunds() public view returns (uint256) {
        return
            IERC20(wantToken).balanceOf(address(this)) + totalExecutorFunds();
    }

    /*///////////////////////////////////////////////////////////////
                    EXECUTOR DEPOSIT/WITHDRAWAL LOGIC
    //////////////////////////////////////////////////////////////*/

    /// @notice list of trade executors connected to vault.
    AddrArrayLib.Addresses tradeExecutorsList;

    /// @notice Emitted after the vault deposits into a executor contract.
    /// @param executor The executor that was deposited into.
    /// @param underlyingAmount The amount of underlying tokens that were deposited.
    event ExecutorDeposit(address indexed executor, uint256 underlyingAmount);

    /// @notice Emitted after the vault withdraws funds from a executor contract.
    /// @param executor The executor that was withdrawn from.
    /// @param underlyingAmount The amount of underlying tokens that were withdrawn.
    event ExecutorWithdrawal(
        address indexed executor,
        uint256 underlyingAmount
    );

    /// @notice Deposit given amount of want tokens into valid executor.
    /// @param _executor The executor to deposit into.
    /// @param _amount The amount of want tokens to deposit.
    function depositIntoExecutor(address _executor, uint256 _amount)
        public
        nonReentrant
    {
        isActiveExecutor(_executor);
        onlyKeeper();
        require(_amount > 0, "ZERO_AMOUNT");
        IERC20(wantToken).safeTransfer(_executor, _amount);
        emit ExecutorDeposit(_executor, _amount);
    }

    /// @notice Withdraw given amount of want tokens into valid executor.
    /// @param _executor The executor to withdraw tokens from.
    /// @param _amount The amount of want tokens to withdraw.
    function withdrawFromExecutor(address _executor, uint256 _amount)
        public
        nonReentrant
    {
        isActiveExecutor(_executor);
        onlyKeeper();
        require(_amount > 0, "ZERO_AMOUNT");
        IERC20(wantToken).safeTransferFrom(_executor, address(this), _amount);
        emit ExecutorWithdrawal(_executor, _amount);
    }

    /*///////////////////////////////////////////////////////////////
                           FEE CONFIGURATION
    //////////////////////////////////////////////////////////////*/
    /// @notice lagging value of vault total funds.
    /// @dev value intialized to max to prevent slashing on first deposit.
    uint256 public prevVaultFunds = type(uint256).max;
    /// @dev Perfomance fee for the vault.
    uint256 public performanceFee;
    /// @notice Emitted after fee updation.
    /// @param fee The new performance fee on vault.
    event UpdatePerformanceFee(uint256 fee);

    /// @notice Updates the performance fee on the vault.
    /// @param _fee The new performance fee on the vault.
    /// @dev The new fee must be always less than 50% of yield.
    function setPerformanceFee(uint256 _fee) public {
        onlyGovernance();
        require(_fee < MAX_BPS / 2, "FEE_TOO_HIGH");
        performanceFee = _fee;
        emit UpdatePerformanceFee(_fee);
    }

    /// @notice Emitted when a fees are collected.
    /// @param collectedFees The amount of fees collected.
    event FeesCollected(uint256 collectedFees);

    /// @notice Calculates and collects the fees from the vault.
    /// @dev This function sends all the accured fees to governance.
    /// checks the yield made since previous harvest and
    /// calculates the fee based on it. Also note: this function
    /// should be called before processing any new deposits/withdrawals.
    function collectFees() internal {
        uint256 currentFunds = totalVaultFunds();
        // collect fees only when profit is made.
        if ((performanceFee > 0) && (currentFunds > prevVaultFunds)) {
            uint256 yieldEarned = (currentFunds - prevVaultFunds);
            // normalization by MAX_BPS
            uint256 fees = ((yieldEarned * performanceFee) / MAX_BPS);
            IERC20(wantToken).safeTransfer(governance, fees);
            emit FeesCollected(fees);
        }
    }

    modifier ensureFeesAreCollected() {
        collectFees();
        _;
        // update vault funds after fees are collected.
        prevVaultFunds = totalVaultFunds();
    }

    /*///////////////////////////////////////////////////////////////
                    EXECUTOR ADDITION/REMOVAL LOGIC
    //////////////////////////////////////////////////////////////*/
    /// @notice Emitted when executor is added to vault.
    /// @param executor The address of added executor.
    event ExecutorAdded(address indexed executor);

    /// @notice Emitted when executor is removed from vault.
    /// @param executor The address of removed executor.
    event ExecutorRemoved(address indexed executor);

    /// @notice Adds a trade executor, enabling it to execute trades.
    /// @param _tradeExecutor The address of _tradeExecutor contract.
    function addExecutor(address _tradeExecutor) public {
        onlyGovernance();
        isValidAddress(_tradeExecutor);
        require(
            ITradeExecutor(_tradeExecutor).vault() == address(this),
            "INVALID_VAULT"
        );
        require(
            IERC20(wantToken).allowance(_tradeExecutor, address(this)) > 0,
            "NO_ALLOWANCE"
        );
        tradeExecutorsList.pushAddress(_tradeExecutor);
        emit ExecutorAdded(_tradeExecutor);
    }

    /// @notice Adds a trade executor, enabling it to execute trades.
    /// @param _tradeExecutor The address of _tradeExecutor contract.
    /// @dev make sure all funds are withdrawn from executor before removing.
    function removeExecutor(address _tradeExecutor) public {
        onlyGovernance();
        isValidAddress(_tradeExecutor);
        // check if executor attached to vault.
        isActiveExecutor(_tradeExecutor);

        (uint256 executorFunds, uint256 blockUpdated) = ITradeExecutor(
            _tradeExecutor
        ).totalFunds();
        areFundsUpdated(blockUpdated);
        require(executorFunds < DUST_LIMIT, "FUNDS_TOO_HIGH");
        tradeExecutorsList.removeAddress(_tradeExecutor);
        emit ExecutorRemoved(_tradeExecutor);
    }

    /// @notice gives the number of trade executors.
    /// @return The number of trade executors.
    function totalExecutors() public view returns (uint256) {
        return tradeExecutorsList.size();
    }

    /// @notice Returns trade executor at given index.
    /// @return The executor address at given valid index.
    function executorByIndex(uint256 _index) public view returns (address) {
        return tradeExecutorsList.getAddressAtIndex(_index);
    }

    /// @notice Calculates funds held by all executors in want token.
    /// @return Sum of all funds held by executors.
    function totalExecutorFunds() public view returns (uint256) {
        uint256 totalFunds = 0;
        for (uint256 i = 0; i < totalExecutors(); i++) {
            address executor = executorByIndex(i);
            (uint256 executorFunds, uint256 blockUpdated) = ITradeExecutor(
                executor
            ).totalFunds();
            areFundsUpdated(blockUpdated);
            totalFunds += executorFunds;
        }
        return totalFunds;
    }

    /*///////////////////////////////////////////////////////////////
                    GOVERNANCE ACTIONS
    //////////////////////////////////////////////////////////////*/

    /// @notice Emitted when a batcher is updated.
    /// @param oldBatcher The address of the current batcher.
    /// @param newBatcher The  address of new batcher.
    event UpdatedBatcher(
        address indexed oldBatcher,
        address indexed newBatcher
    );

    /// @notice Changes the batcher address.
    /// @dev  This can only be called by governance.
    /// @param _batcher The address to for new batcher.
    function setBatcher(address _batcher) public {
        onlyGovernance();
        emit UpdatedBatcher(batcher, _batcher);
        batcher = _batcher;
    }

    /// @notice Emitted batcherOnlyDeposit is enabled.
    /// @param state The state of depositing only via batcher.
    event UpdatedBatcherOnlyDeposit(bool state);

    /// @notice Enables/disables deposits with batcher only.
    /// @dev  This can only be called by governance.
    /// @param _batcherOnlyDeposit if true vault can accept deposit via batcher only or else anyone can deposit.
    function setBatcherOnlyDeposit(bool _batcherOnlyDeposit) public {
        onlyGovernance();
        batcherOnlyDeposit = _batcherOnlyDeposit;
        emit UpdatedBatcherOnlyDeposit(_batcherOnlyDeposit);
    }

    /// @notice Nominates new governance address.
    /// @dev  Governance will only be changed if the new governance accepts it. It will be pending till then.
    /// @param _governance The address of new governance.
    function setGovernance(address _governance) public {
        onlyGovernance();
        pendingGovernance = _governance;
    }

    /// @notice Emitted when governance is updated.
    /// @param oldGovernance The address of the current governance.
    /// @param newGovernance The address of new governance.
    event UpdatedGovernance(
        address indexed oldGovernance,
        address indexed newGovernance
    );

    /// @notice The nomine of new governance address proposed by `setGovernance` function can accept the governance.
    /// @dev  This can only be called by address of pendingGovernance.
    function acceptGovernance() public {
        require(msg.sender == pendingGovernance, "INVALID_ADDRESS");
        emit UpdatedGovernance(governance, pendingGovernance);
        governance = pendingGovernance;
    }

    /// @notice Emitted when keeper is updated.
    /// @param keeper The address of the new keeper.
    event UpdatedKeeper(address indexed keeper);

    /// @notice Sets new keeper address.
    /// @dev  This can only be called by governance.
    /// @param _keeper The address of new keeper.
    function setKeeper(address _keeper) public {
        onlyGovernance();
        keeper = _keeper;
        emit UpdatedKeeper(_keeper);
    }

    /// @notice Emitted when emergencyMode status is updated.
    /// @param emergencyMode boolean indicating state of emergency.
    event EmergencyModeStatus(bool emergencyMode);

    /// @notice sets emergencyMode.
    /// @dev  This can only be called by governance.
    /// @param _emergencyMode if true, vault will be in emergency mode.
    function setEmergencyMode(bool _emergencyMode) public {
        onlyGovernance();
        emergencyMode = _emergencyMode;
        batcherOnlyDeposit = true;
        batcher = address(0);
        emit EmergencyModeStatus(_emergencyMode);
    }

    /// @notice Removes invalid tokens from the vault.
    /// @dev  This is used as fail safe to remove want tokens from the vault during emergency mode
    /// can be called by anyone to send funds to governance.
    /// @param _token The address of token to be removed.
    function sweep(address _token) public {
        isEmergencyMode();
        IERC20(_token).safeTransfer(
            governance,
            IERC20(_token).balanceOf(address(this))
        );
    }

    /*///////////////////////////////////////////////////////////////
                    ACCESS MODIFERS
    //////////////////////////////////////////////////////////////*/
    /// @dev Checks if the sender is the governance.
    function onlyGovernance() internal view {
        require(msg.sender == governance, "ONLY_GOV");
    }

    /// @dev Checks if the sender is the keeper.
    function onlyKeeper() internal view {
        require(msg.sender == keeper, "ONLY_KEEPER");
    }

    /// @dev Checks if the sender is the batcher.
    function onlyBatcher() internal view {
        if (batcherOnlyDeposit) {
            require(msg.sender == batcher, "ONLY_BATCHER");
        }
    }

    /// @dev Checks if emergency mode is enabled.
    function isEmergencyMode() internal view {
        require(emergencyMode == true, "EMERGENCY_MODE");
    }

    /// @dev Checks if the address is valid.
    function isValidAddress(address _addr) internal pure {
        require(_addr != address(0), "NULL_ADDRESS");
    }

    /// @dev Checks if the tradeExecutor is valid.
    function isActiveExecutor(address _tradeExecutor) internal view {
        require(tradeExecutorsList.exists(_tradeExecutor), "INVALID_EXECUTOR");
    }

    /// @dev Checks if funds are updated.
    function areFundsUpdated(uint256 _blockUpdated) internal view {
        require(
            block.number <= _blockUpdated + BLOCK_LIMIT,
            "FUNDS_NOT_UPDATED"
        );
    }
}

/// SPDX-License-Identifier: GPL-3.0-or-later
pragma solidity ^0.8.0;

interface IVault {
    function keeper() external view returns (address);

    function governance() external view returns (address);

    function wantToken() external view returns (address);

    function deposit(uint256 amountIn, address receiver)
        external
        returns (uint256 shares);

    function withdraw(uint256 sharesIn, address receiver)
        external
        returns (uint256 amountOut);
}

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

library AddrArrayLib {
    using AddrArrayLib for Addresses;

    struct Addresses {
        address[] _items;
    }

    /**
     * @notice push an address to the array
     * @dev if the address already exists, it will not be added again
     * @param self Storage array containing address type variables
     * @param element the element to add in the array
     */
    function pushAddress(Addresses storage self, address element) internal {
        if (!exists(self, element)) {
            self._items.push(element);
        }
    }

    /**
     * @notice remove an address from the array
     * @dev finds the element, swaps it with the last element, and then deletes it;
     *      returns a boolean whether the element was found and deleted
     * @param self Storage array containing address type variables
     * @param element the element to remove from the array
     */
    function removeAddress(Addresses storage self, address element) internal {
        for (uint256 i = 0; i < self.size(); i++) {
            if (self._items[i] == element) {
                self._items[i] = self._items[self.size() - 1];
                self._items.pop();
            }
        }
    }

    /**
     * @notice get the address at a specific index from array
     * @dev revert if the index is out of bounds
     * @param self Storage array containing address type variables
     * @param index the index in the array
     */
    function getAddressAtIndex(Addresses memory self, uint256 index)
        internal
        view
        returns (address)
    {
        require(index < size(self), "INVALID_INDEX");
        return self._items[index];
    }

    /**
     * @notice get the size of the array
     * @param self Storage array containing address type variables
     */
    function size(Addresses memory self) internal view returns (uint256) {
        return self._items.length;
    }

    /**
     * @notice check if an element exist in the array
     * @param self Storage array containing address type variables
     * @param element the element to check if it exists in the array
     */
    function exists(Addresses memory self, address element)
        internal
        view
        returns (bool)
    {
        for (uint256 i = 0; i < self.size(); i++) {
            if (self._items[i] == element) {
                return true;
            }
        }
        return false;
    }

    /**
     * @notice get the array
     * @param self Storage array containing address type variables
     */
    function getAllAddresses(Addresses memory self)
        internal
        view
        returns (address[] memory)
    {
        return self._items;
    }
}

//SPDX-License-Identifier: GPL-3.0-only
pragma solidity ^0.8.0;

interface ITradeExecutor {
    struct ActionStatus {
        bool inProcess;
        address from;
    }
    function vault() external view returns (address);

    function depositStatus() external returns (bool, address);

    function withdrawalStatus() external returns (bool, address);

    function initiateDeposit(bytes calldata _data) external;

    function confirmDeposit() external;

    function initateWithdraw(bytes calldata _data) external;

    function confirmWithdraw() external;

    function totalFunds()
        external
        view
        returns (uint256 posValue, uint256 lastUpdatedBlock);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

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

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

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

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

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

// 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;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC20/ERC20.sol)

pragma solidity ^0.8.0;

import "./IERC20.sol";
import "./extensions/IERC20Metadata.sol";
import "../../utils/Context.sol";

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin Contracts guidelines: functions revert
 * instead returning `false` on failure. This behavior is nonetheless
 * conventional and does not conflict with the expectations of ERC20
 * applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20, IERC20Metadata {
    mapping(address => uint256) private _balances;

    mapping(address => mapping(address => uint256)) private _allowances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;

    /**
     * @dev Sets the values for {name} and {symbol}.
     *
     * The default value of {decimals} is 18. To select a different value for
     * {decimals} you should overload it.
     *
     * All two of these values are immutable: they can only be set once during
     * construction.
     */
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5.05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the value {ERC20} uses, unless this function is
     * overridden;
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view virtual override returns (uint8) {
        return 18;
    }

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view virtual override returns (uint256) {
        return _balances[account];
    }

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

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on
     * `transferFrom`. This is semantically equivalent to an infinite approval.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20}.
     *
     * NOTE: Does not update the allowance if the current allowance
     * is the maximum `uint256`.
     *
     * Requirements:
     *
     * - `from` and `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     * - the caller must have allowance for ``from``'s tokens of at least
     * `amount`.
     */
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) public virtual override returns (bool) {
        address spender = _msgSender();
        _spendAllowance(from, spender, amount);
        _transfer(from, to, amount);
        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, _allowances[owner][spender] + addedValue);
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        address owner = _msgSender();
        uint256 currentAllowance = _allowances[owner][spender];
        require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
        unchecked {
            _approve(owner, 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:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     */
    function _transfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(from, to, amount);

        uint256 fromBalance = _balances[from];
        require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
        unchecked {
            _balances[from] = fromBalance - amount;
        }
        _balances[to] += amount;

        emit Transfer(from, to, amount);

        _afterTokenTransfer(from, to, amount);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply += amount;
        _balances[account] += amount;
        emit Transfer(address(0), account, amount);

        _afterTokenTransfer(address(0), account, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        unchecked {
            _balances[account] = accountBalance - amount;
        }
        _totalSupply -= amount;

        emit Transfer(account, address(0), amount);

        _afterTokenTransfer(account, address(0), amount);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
     *
     * This internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

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

    /**
     * @dev Spend `amount` form the allowance of `owner` toward `spender`.
     *
     * Does not update the allowance amount in case of infinite allowance.
     * Revert if not enough allowance is available.
     *
     * Might emit an {Approval} event.
     */
    function _spendAllowance(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        uint256 currentAllowance = allowance(owner, spender);
        if (currentAllowance != type(uint256).max) {
            require(currentAllowance >= amount, "ERC20: insufficient allowance");
            unchecked {
                _approve(owner, spender, currentAllowance - amount);
            }
        }
    }

    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}

    /**
     * @dev Hook that is called after any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * has been transferred to `to`.
     * - when `from` is zero, `amount` tokens have been minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens have been burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _afterTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (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 `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);

    /**
     * @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);
}

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

pragma solidity ^0.8.0;

/**
 * @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 ReentrancyGuard {
    // 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;

    constructor() {
        _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;
    }
}

// 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");
        }
    }
}

// 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);
}