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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

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

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

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

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

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

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

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby disabling 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/security/Pausable.sol



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

pragma solidity ^0.8.0;

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

/**
 * @dev Contract module which allows children to implement an emergency stop
 * mechanism that can be triggered by an authorized account.
 *
 * This module is used through inheritance. It will make available the
 * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
 * the functions of your contract. Note that they will not be pausable by
 * simply including this module, only once the modifiers are put in place.
 */
abstract contract Pausable is Context {
    /**
     * @dev Emitted when the pause is triggered by `account`.
     */
    event Paused(address account);

    /**
     * @dev Emitted when the pause is lifted by `account`.
     */
    event Unpaused(address account);

    bool private _paused;

    /**
     * @dev Initializes the contract in unpaused state.
     */
    constructor() {
        _paused = false;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is not paused.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    modifier whenNotPaused() {
        _requireNotPaused();
        _;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    modifier whenPaused() {
        _requirePaused();
        _;
    }

    /**
     * @dev Returns true if the contract is paused, and false otherwise.
     */
    function paused() public view virtual returns (bool) {
        return _paused;
    }

    /**
     * @dev Throws if the contract is paused.
     */
    function _requireNotPaused() internal view virtual {
        require(!paused(), "Pausable: paused");
    }

    /**
     * @dev Throws if the contract is not paused.
     */
    function _requirePaused() internal view virtual {
        require(paused(), "Pausable: not paused");
    }

    /**
     * @dev Triggers stopped state.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    function _pause() internal virtual whenNotPaused {
        _paused = true;
        emit Paused(_msgSender());
    }

    /**
     * @dev Returns to normal state.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    function _unpause() internal virtual whenPaused {
        _paused = false;
        emit Unpaused(_msgSender());
    }
}

// File: @openzeppelin/contracts/security/ReentrancyGuard.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (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() {
        _nonReentrantBefore();
        _;
        _nonReentrantAfter();
    }

    function _nonReentrantBefore() private {
        // On the first call to nonReentrant, _status will be _NOT_ENTERED
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

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

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

    /**
     * @dev Returns true if the reentrancy guard is currently set to "entered", which indicates there is a
     * `nonReentrant` function in the call stack.
     */
    function _reentrancyGuardEntered() internal view returns (bool) {
        return _status == _ENTERED;
    }
}

// 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/extensions/IERC20Permit.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/extensions/IERC20Permit.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
 * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
 *
 * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
 * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
 * need to send a transaction, and thus is not required to hold Ether at all.
 */
interface IERC20Permit {
    /**
     * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
     * given ``owner``'s signed approval.
     *
     * IMPORTANT: The same issues {IERC20-approve} has related to transaction
     * ordering also apply here.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `deadline` must be a timestamp in the future.
     * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
     * over the EIP712-formatted function arguments.
     * - the signature must use ``owner``'s current nonce (see {nonces}).
     *
     * For more information on the signature format, see the
     * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
     * section].
     */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    /**
     * @dev Returns the current nonce for `owner`. This value must be
     * included whenever a signature is generated for {permit}.
     *
     * Every successful call to {permit} increases ``owner``'s nonce by one. This
     * prevents a signature from being used multiple times.
     */
    function nonces(address owner) external view returns (uint256);

    /**
     * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
     */
    // solhint-disable-next-line func-name-mixedcase
    function DOMAIN_SEPARATOR() external view returns (bytes32);
}

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

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

    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

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

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

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

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

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

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";
import "../extensions/IERC20Permit.sol";
import "../../../utils/Address.sol";

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

    /**
     * @dev Transfer `value` amount of `token` from the calling contract to `to`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    /**
     * @dev Transfer `value` amount of `token` from `from` to `to`, spending the approval given by `from` to the
     * calling contract. If `token` returns no value, non-reverting calls are assumed to be successful.
     */
    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));
    }

    /**
     * @dev Increase the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 oldAllowance = token.allowance(address(this), spender);
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance + value));
    }

    /**
     * @dev Decrease the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    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");
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance - value));
        }
    }

    /**
     * @dev Set the calling contract's allowance toward `spender` to `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful. Compatible with tokens that require the approval to be set to
     * 0 before setting it to a non-zero value.
     */
    function forceApprove(IERC20 token, address spender, uint256 value) internal {
        bytes memory approvalCall = abi.encodeWithSelector(token.approve.selector, spender, value);

        if (!_callOptionalReturnBool(token, approvalCall)) {
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, 0));
            _callOptionalReturn(token, approvalCall);
        }
    }

    /**
     * @dev Use a ERC-2612 signature to set the `owner` approval toward `spender` on `token`.
     * Revert on invalid signature.
     */
    function safePermit(
        IERC20Permit token,
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal {
        uint256 nonceBefore = token.nonces(owner);
        token.permit(owner, spender, value, deadline, v, r, s);
        uint256 nonceAfter = token.nonces(owner);
        require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address-functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        require(returndata.length == 0 || abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     *
     * This is a variant of {_callOptionalReturn} that silents catches all reverts and returns a bool instead.
     */
    function _callOptionalReturnBool(IERC20 token, bytes memory data) private returns (bool) {
        // 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 cannot use {Address-functionCall} here since this should return false
        // and not revert is the subcall reverts.

        (bool success, bytes memory returndata) = address(token).call(data);
        return
            success && (returndata.length == 0 || abi.decode(returndata, (bool))) && Address.isContract(address(token));
    }
}

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (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
     *
     * Furthermore, `isContract` will also return true if the target contract within
     * the same transaction is already scheduled for destruction by `SELFDESTRUCT`,
     * which only has an effect at the end of a transaction.
     * ====
     *
     * [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://consensys.net/diligence/blog/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/v0.8.0/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 functionCallWithValue(target, data, 0, "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");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, 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) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, 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) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
     * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
     *
     * _Available since v4.8._
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                // only check isContract if the call was successful and the return data is empty
                // otherwise we already know that it was a contract
                require(isContract(target), "Address: call to non-contract");
            }
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

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

    function _revert(bytes memory returndata, string memory errorMessage) private pure {
        // Look for revert reason and bubble it up if present
        if (returndata.length > 0) {
            // The easiest way to bubble the revert reason is using memory via assembly
            /// @solidity memory-safe-assembly
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert(errorMessage);
        }
    }
}

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



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

pragma solidity ^0.8.0;

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

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

// File: contracts/farm/interfaces/IMasterChefV2.sol



// SPDX-License-Identifier: GPLv3
pragma solidity 0.8.19;

interface IMasterChefV2 {
    function BBC() external view returns (address);

    function deposit(uint256 _pid, uint256 _amount) external;

    function withdraw(uint256 _pid, uint256 _amount) external;

    function pendingBBC(
        uint256 _pid,
        address _user
    ) external view returns (uint256);

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

    function emergencyWithdraw(uint256 _pid) external;

    function lpToken(uint256 _pid) external view returns (address);

    function poolLength() external view returns (uint256 pools);

    function getBoostMultiplier(
        address _user,
        uint256 _pid
    ) external view returns (uint256);

    function updateBoostMultiplier(
        address _user,
        uint256 _pid,
        uint256 _newMultiplier
    ) external;
}

// File: contracts/pool/CakePool.sol



// SPDX-License-Identifier: GPLv3
pragma solidity 0.8.19;

import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "@openzeppelin/contracts/security/Pausable.sol";
import "../farm/interfaces/IMasterChefV2.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";

contract CakePool is Ownable, Pausable, ReentrancyGuard {
    using SafeERC20 for IERC20;

    struct UserInfo {
        uint256 shares; // number of shares for a user.
        uint256 lastDepositedTime; // keep track of deposited time for potential penalty.
        uint256 lastUserActionAmount; // keep track of token deposited at the last user action.
        uint256 lastUserActionTime; // keep track of the last user action time.
        uint256 lockStartTime; // lock start time.
        uint256 lockEndTime; // lock end time.
        uint256 userBoostedShare; // boost share, in order to give the user higher reward. The user only enjoys the reward, so the principal needs to be recorded as a debt.
        bool locked; //lock status.
        uint256 lockedAmount; // amount deposited during lock period.
    }

    IERC20 public immutable token; // staking token.
    IERC20 public immutable bbc; // earning token.

    IMasterChefV2 public immutable masterchefV2;

    mapping(address => UserInfo) public userInfo;
    mapping(address => bool) public freePerformanceFeeUsers; // free performance fee users.
    mapping(address => bool) public freeWithdrawFeeUsers; // free withdraw fee users.
    mapping(address => bool) public freeOverdueFeeUsers; // free overdue fee users.

    uint256 public totalShares;
    address public admin;
    address public treasury;
    address public operator;
    uint256 public bbcPoolPID;
    uint256 public totalBoostDebt; // total boost debt.
    uint256 public totalLockedAmount; // total lock amount.

    uint256 public constant MAX_PERFORMANCE_FEE = 2000; // 20%
    uint256 public constant MAX_WITHDRAW_FEE = 500; // 5%
    uint256 public constant MAX_OVERDUE_FEE = 100 * 1e10; // 100%
    uint256 public constant MAX_WITHDRAW_FEE_PERIOD = 1 weeks; // 1 week
    uint256 public constant MIN_LOCK_DURATION = 1 weeks; // 1 week
    uint256 public constant MAX_LOCK_DURATION_LIMIT = 1000 days; // 1000 days
    uint256 public constant BOOST_WEIGHT_LIMIT = 5000 * 1e10; // 5000%
    uint256 public constant PRECISION_FACTOR = 1e12; // precision factor.
    uint256 public constant PRECISION_FACTOR_SHARE = 1e28; // precision factor for share.
    uint256 public constant MIN_DEPOSIT_AMOUNT = 0.00001 ether;
    uint256 public constant MIN_WITHDRAW_AMOUNT = 0.00001 ether;
    uint256 public UNLOCK_FREE_DURATION = 2 weeks; // 2 week
    uint256 public MAX_LOCK_DURATION = 365 days; // 365 days
    uint256 public DURATION_FACTOR = 365 days; // 365 days, in order to calculate user additional boost.
    uint256 public DURATION_FACTOR_OVERDUE = 90 days; // 90 days, in order to calculate overdue fee.
    uint256 public BOOST_WEIGHT = 2000 * 1e10; // 2000%
    uint256 public constant FEE_RATE_SCALE = 10000;

    uint256 public performanceFee = 200; // 2%
    uint256 public withdrawFee = 400; // 4%
    uint256 public overdueFee = 100 * 1e10; // 100%
    uint256 public withdrawFeePeriod = 72 hours; // 3 days

    event Deposit(
        address indexed sender,
        uint256 amount,
        uint256 shares,
        uint256 duration,
        uint256 lastDepositedTime
    );
    event Withdraw(address indexed sender, uint256 amount, uint256 shares);
    event Harvest(address indexed sender, uint256 amount);
    event Pause();
    event Unpause();
    event Init();
    event Lock(
        address indexed sender,
        uint256 lockedAmount,
        uint256 shares,
        uint256 lockedDuration,
        uint256 blockTimestamp
    );
    event Unlock(
        address indexed sender,
        uint256 amount,
        uint256 blockTimestamp
    );
    event NewAdmin(address admin);
    event NewTreasury(address treasury);
    event NewOperator(address operator);
    event FreeFeeUser(address indexed user, bool indexed free);
    event NewPerformanceFee(uint256 performanceFee);
    event NewWithdrawFee(uint256 withdrawFee);
    event NewOverdueFee(uint256 overdueFee);
    event NewWithdrawFeePeriod(uint256 withdrawFeePeriod);
    event NewMaxLockDuration(uint256 maxLockDuration);
    event NewDurationFactor(uint256 durationFactor);
    event NewDurationFactorOverdue(uint256 durationFactorOverdue);
    event NewUnlockFreeDuration(uint256 unlockFreeDuration);
    event NewBoostWeight(uint256 boostWeight);

    /**
     * @notice Constructor
     * @param _token: Staking token contract
     * @param _masterchefV2: MasterChefV2 contract
     * @param _admin: address of the admin
     * @param _treasury: address of the treasury (collects fees)
     * @param _operator: address of operator
     * @param _pid: bbc pool ID in MasterChefV2
     */
    constructor(
        IERC20 _token,
        IMasterChefV2 _masterchefV2,
        address _admin,
        address _treasury,
        address _operator,
        uint256 _pid
    ) {
        require(address(_token) != address(0), "Invalid token");
        require(address(_masterchefV2) != address(0), "Invalid masterchefV2");
        require(_admin != address(0), "Invalid admin");
        require(_treasury != address(0), "Invalid treasury");
        require(_operator != address(0), "Invalid operator");
        token = _token;
        bbc = IERC20(_masterchefV2.BBC());
        masterchefV2 = _masterchefV2;
        admin = _admin;
        treasury = _treasury;
        operator = _operator;
        bbcPoolPID = _pid;
    }

    /**
     * @notice Deposits a dummy token to `MASTER_CHEF` MCV2.
     * It will transfer all the `dummyToken` in the msg sender address.
     * @param dummyToken The address of the token to be deposited into MCV2.
     */
    function init(IERC20 dummyToken, uint256 amount) public onlyOwner {
        uint256 balance = dummyToken.balanceOf(msg.sender);
        require(balance != 0, "Balance must exceed 0");
        if (amount == 0 || amount > balance) amount = balance;
        dummyToken.safeTransferFrom(msg.sender, address(this), amount);
        dummyToken.approve(address(masterchefV2), amount);
        masterchefV2.deposit(bbcPoolPID, amount);
        emit Init();
    }

    function close() public onlyOwner {
        masterchefV2.emergencyWithdraw(bbcPoolPID);
    }

    /**
     * @notice Checks if the msg.sender is the admin address.
     */
    modifier onlyAdmin() {
        require(msg.sender == admin, "admin: wut?");
        _;
    }

    /**
     * @notice Checks if the msg.sender is either the bbc owner address or the operator address.
     */
    modifier onlyOperatorOrBBCOwner(address _user) {
        require(
            msg.sender == _user || msg.sender == operator,
            "Not operator or bbc owner"
        );
        _;
    }

    /**
     * @notice Update user share When need to unlock or charges a fee.
     * @param _user: User address
     */
    function updateUserShare(address _user) internal virtual {
        UserInfo storage user = userInfo[_user];
        if (user.shares > 0) {
            if (user.locked) {
                // Calculate the user's current token amount and update related parameters.
                uint256 currentAmount = (balanceOf() * (user.shares)) /
                    totalShares -
                    user.userBoostedShare;
                totalBoostDebt -= user.userBoostedShare;
                user.userBoostedShare = 0;
                totalShares -= user.shares;
                //Charge a overdue fee after the free duration has expired.
                if (
                    !freeOverdueFeeUsers[_user] &&
                    ((user.lockEndTime + UNLOCK_FREE_DURATION) <
                        block.timestamp)
                ) {
                    uint256 earnAmount = currentAmount - user.lockedAmount;
                    uint256 overdueDuration = block.timestamp -
                        user.lockEndTime -
                        UNLOCK_FREE_DURATION;
                    if (overdueDuration > DURATION_FACTOR_OVERDUE) {
                        overdueDuration = DURATION_FACTOR_OVERDUE;
                    }
                    // Rates are calculated based on the user's overdue duration.
                    uint256 overdueWeight = (overdueDuration * overdueFee) /
                        DURATION_FACTOR_OVERDUE;
                    uint256 currentOverdueFee = (earnAmount * overdueWeight) /
                        PRECISION_FACTOR;
                    uint256 feeHalf = currentOverdueFee / 2;
                    bbc.safeTransfer(treasury, feeHalf);
                    bbc.safeTransfer(
                        address(0xdead),
                        currentOverdueFee - feeHalf
                    );
                    currentAmount -= currentOverdueFee;
                }
                // Recalculate the user's share.
                uint256 pool = balanceOf();
                uint256 currentShares;
                if (totalShares != 0) {
                    currentShares =
                        (currentAmount * totalShares) /
                        (pool - currentAmount);
                } else {
                    currentShares = currentAmount;
                }
                user.shares = currentShares;
                totalShares += currentShares;
                // After the lock duration, update related parameters.
                if (user.lockEndTime < block.timestamp) {
                    user.locked = false;
                    user.lockStartTime = 0;
                    user.lockEndTime = 0;
                    totalLockedAmount -= user.lockedAmount;
                    user.lockedAmount = 0;
                    emit Unlock(_user, currentAmount, block.timestamp);
                }
            } else if (!freePerformanceFeeUsers[_user]) {
                // Calculate Performance fee.
                uint256 totalAmount = (user.shares * balanceOf()) / totalShares;
                totalShares -= user.shares;
                user.shares = 0;
                uint256 earnAmount = totalAmount -
                    user.lastUserActionAmount;
                uint256 currentPerformanceFee = (earnAmount *
                    performanceFee) / FEE_RATE_SCALE;
                if (currentPerformanceFee > 0) {
                    bbc.safeTransfer(treasury, currentPerformanceFee);
                    totalAmount -= currentPerformanceFee;
                }
                // Recalculate the user's share.
                uint256 pool = balanceOf();
                uint256 newShares;
                if (totalShares != 0) {
                    newShares =
                        (totalAmount * totalShares) /
                        (pool - totalAmount);
                } else {
                    newShares = totalAmount;
                }
                user.shares = newShares;
                totalShares += newShares;
            }
        }
    }

    /**
     * @notice Unlock user bbc funds.
     * @dev Only possible when contract not paused.
     * @param _user: User address
     */
    function unlock(
        address _user
    ) public onlyOperatorOrBBCOwner(_user) whenNotPaused nonReentrant {
        UserInfo storage user = userInfo[_user];
        require(
            user.locked && user.lockEndTime < block.timestamp,
            "Cannot unlock yet"
        );
        depositOperation(0, 0, _user);
    }

    /**
     * @notice Deposit funds into the BBC Pool.
     * @dev Only possible when contract not paused.
     * @param _amount: number of tokens to deposit (in BBC)
     * @param _lockDuration: Token lock duration
     */
    function deposit(
        uint256 _amount,
        uint256 _lockDuration
    ) public whenNotPaused nonReentrant {
        require(_amount > 0 || _lockDuration > 0, "Nothing to deposit");
        depositOperation(_amount, _lockDuration, msg.sender);
    }

    /**
     * @notice The operation of deposite.
     * @param _amount: number of tokens to deposit (in BBC)
     * @param _lockDuration: Token lock duration
     * @param _user: User address
     */
    function depositOperation(
        uint256 _amount,
        uint256 _lockDuration,
        address _user
    ) internal virtual {
        UserInfo storage user = userInfo[_user];
        if (user.shares == 0 || _amount > 0) {
            require(_amount > MIN_DEPOSIT_AMOUNT, "Deposit amount must be greater than MIN_DEPOSIT_AMOUNT");
        }
        // Calculate the total lock duration and check whether the lock duration meets the conditions.
        uint256 totalLockDuration = _lockDuration;
        uint256 userLockEndTime = user.lockEndTime;
        if (userLockEndTime >= block.timestamp) {
            // Adding funds during the lock duration is equivalent to re-locking the position, needs to update some variables.
            if (_amount > 0) {
                user.lockStartTime = block.timestamp;
                totalLockedAmount -= user.lockedAmount;
                user.lockedAmount = 0;
            }
            totalLockDuration += userLockEndTime - user.lockStartTime;
        }
        require(
            _lockDuration == 0 || totalLockDuration >= MIN_LOCK_DURATION,
            "Minimum lock period is one week"
        );
        require(
            totalLockDuration <= MAX_LOCK_DURATION,
            "Maximum lock period exceeded"
        );

        // Harvest tokens from Masterchef.
        harvest();

        // Handle stock funds.
        if (totalShares == 0) {
            uint256 stockAmount = bbc.balanceOf(address(this));
            bbc.safeTransfer(treasury, stockAmount);
        }
        // Update user share.
        updateUserShare(_user);

        // Update lock duration.
        if (_lockDuration > 0) {
            if (userLockEndTime < block.timestamp) {
                user.lockStartTime = block.timestamp;
                userLockEndTime = block.timestamp + _lockDuration;
            } else {
                userLockEndTime += _lockDuration;
            }
            user.locked = true;
            user.lockEndTime = userLockEndTime;
        }

        uint256 currentShares;
        uint256 currentAmount;
        uint256 userCurrentLockedBalance;
        uint256 pool = balanceOf();
        if (_amount > 0) {
            token.safeTransferFrom(_user, address(this), _amount);
            currentAmount = _amount;
        }

        // Calculate lock funds
        if (user.shares > 0 && user.locked) {
            userCurrentLockedBalance = (pool * user.shares) / totalShares;
            currentAmount += userCurrentLockedBalance;
            totalShares -= user.shares;
            user.shares = 0;

            // Update lock amount
            if (user.lockStartTime == block.timestamp) {
                user.lockedAmount = userCurrentLockedBalance;
                totalLockedAmount += userCurrentLockedBalance;
            }
        }
        if (totalShares != 0) {
            currentShares =
                (currentAmount * totalShares) /
                (pool - userCurrentLockedBalance);
        } else {
            currentShares = currentAmount;
        }

        // Calculate the boost weight share.
        if (userLockEndTime > user.lockStartTime) {
            // Calculate boost share.
            uint256 boostWeight = ((userLockEndTime - user.lockStartTime) *
                BOOST_WEIGHT) / DURATION_FACTOR;
            uint256 boostShares = (boostWeight * currentShares) /
                PRECISION_FACTOR;
            currentShares += boostShares;
            user.shares += currentShares;

            // Calculate boost share , the user only enjoys the reward, so the principal needs to be recorded as a debt.
            uint256 userBoostedShare = (boostWeight * currentAmount) /
                PRECISION_FACTOR;
            user.userBoostedShare += userBoostedShare;
            totalBoostDebt += userBoostedShare;

            // Update lock amount.
            user.lockedAmount += _amount;
            totalLockedAmount += _amount;

            emit Lock(
                _user,
                user.lockedAmount,
                user.shares,
                (userLockEndTime - user.lockStartTime),
                block.timestamp
            );
        } else {
            user.shares += currentShares;
        }

        if (_amount > 0 || _lockDuration > 0) {
            user.lastDepositedTime = block.timestamp;
        }
        totalShares += currentShares;

        user.lastUserActionAmount =
            (user.shares * balanceOf()) /
            totalShares -
            user.userBoostedShare;

        user.lastUserActionTime = block.timestamp;

        emit Deposit(
            _user,
            _amount,
            currentShares,
            _lockDuration,
            block.timestamp
        );
    }

    /**
     * @notice Withdraw funds from the BBC Pool.
     * @param _amount: Number of amount to withdraw
     */
    function withdrawByAmount(
        uint256 _amount
    ) public whenNotPaused nonReentrant {
        withdrawOperation(0, _amount);
    }

    /**
     * @notice Withdraw funds from the BBC Pool.
     * @param _shares: Number of shares to withdraw
     */
    function withdraw(uint256 _shares) public whenNotPaused nonReentrant {
        require(_shares > 0, "Nothing to withdraw");
        withdrawOperation(_shares, 0);
    }

    /**
     * @notice The operation of withdraw.
     * @param _shares: Number of shares to withdraw
     * @param _amount: Number of amount to withdraw
     */
	function withdrawOperation(uint256 _shares, uint256 _amount) internal virtual {
        UserInfo storage user = userInfo[msg.sender];
        if(_shares==0 && _amount > 0)
            require(_amount > MIN_WITHDRAW_AMOUNT, "Withdraw amount must be greater than MIN_WITHDRAW_AMOUNT");
        else
            require(_shares <= user.shares, "Withdraw amount exceeds balance");
        require(user.lockEndTime < block.timestamp, "Still in lock");

        // Calculate the percent of withdraw shares, when unlocking or calculating the Performance fee, the shares will be updated.
        uint256 currentShare = _shares;
        uint256 sharesPercent = (_shares * PRECISION_FACTOR_SHARE) /
            user.shares;

        // Harvest token from MasterchefV2.
        harvest();

        // Update user share.
        updateUserShare(msg.sender);

        if (_shares == 0 && _amount > 0) {
            uint256 pool = balanceOf();
            currentShare = (_amount * totalShares) / pool; // Calculate equivalent shares
            if (currentShare > user.shares) {
                currentShare = user.shares;
            }
        } else {
            currentShare =
                (sharesPercent * user.shares) /
                PRECISION_FACTOR_SHARE;
        }
        uint256 currentAmount = (balanceOf() * currentShare) / totalShares;
        user.shares -= currentShare;
        totalShares -= currentShare;

        // Calculate withdraw fee
        if (
            !freeWithdrawFeeUsers[msg.sender] &&
            (block.timestamp < user.lastDepositedTime + withdrawFeePeriod)
        ) {
            uint256 currentWithdrawFee = (currentAmount * withdrawFee) /
                FEE_RATE_SCALE;
            token.safeTransfer(treasury, currentWithdrawFee);
            currentAmount -= currentWithdrawFee;
        }
        token.safeTransfer(msg.sender, currentAmount);

        if (user.shares > 0) {
            user.lastUserActionAmount =
                (user.shares * balanceOf()) /
                totalShares;
        } else {
            user.lastUserActionAmount = 0;
        }

        user.lastUserActionTime = block.timestamp;

        emit Withdraw(msg.sender, currentAmount, currentShare);
    }

    /**
     * @notice Withdraw all funds for a user
     */
    function withdrawAll() public {
        withdraw(userInfo[msg.sender].shares);
    }

    /**
     * @notice Harvest pending BBC tokens from MasterChef
     */
    function harvest() internal returns (uint256) {
        uint256 pendingBBC = masterchefV2.pendingBBC(bbcPoolPID, address(this));
        if (pendingBBC > 0) {
            uint256 balBefore = bbc.balanceOf(address(this));
            masterchefV2.withdraw(bbcPoolPID, 0);
            uint256 balAfter = bbc.balanceOf(address(this));
            uint256 balInc = balAfter - balBefore;
            emit Harvest(msg.sender, balInc);
            return balInc;
        }
        return 0;
    }

    /**
     * @notice Set admin address
     * @dev Only callable by the contract owner.
     */
    function setAdmin(address _admin) public onlyOwner {
        require(_admin != address(0), "Cannot be zero address");
        admin = _admin;
        emit NewAdmin(admin);
    }

    /**
     * @notice Set treasury address
     * @dev Only callable by the contract owner.
     */
    function setTreasury(address _treasury) public onlyOwner {
        require(_treasury != address(0), "Cannot be zero address");
        treasury = _treasury;
        emit NewTreasury(treasury);
    }

    /**
     * @notice Set operator address
     * @dev Callable by the contract owner.
     */
    function setOperator(address _operator) public onlyOwner {
        require(_operator != address(0), "Cannot be zero address");
        operator = _operator;
        emit NewOperator(operator);
    }

    /**
     * @notice Set free performance fee address
     * @dev Only callable by the contract admin.
     * @param _user: User address
     * @param _free: true:free false:not free
     */
    function setFreePerformanceFeeUser(
        address _user,
        bool _free
    ) public onlyAdmin {
        require(_user != address(0), "Cannot be zero address");
        freePerformanceFeeUsers[_user] = _free;
        emit FreeFeeUser(_user, _free);
    }

    /**
     * @notice Set free overdue fee address
     * @dev Only callable by the contract admin.
     * @param _user: User address
     * @param _free: true:free false:not free
     */
    function setFreeOverdueFeeUser(address _user, bool _free) public onlyAdmin {
        require(_user != address(0), "Cannot be zero address");
        freeOverdueFeeUsers[_user] = _free;
        emit FreeFeeUser(_user, _free);
    }

    /**
     * @notice Set free withdraw fee address
     * @dev Only callable by the contract admin.
     * @param _user: User address
     * @param _free: true:free false:not free
     */
    function setFreeWithdrawFeeUser(address _user, bool _free) public onlyAdmin {
        require(_user != address(0), "Cannot be zero address");
        freeWithdrawFeeUsers[_user] = _free;
        emit FreeFeeUser(_user, _free);
    }

    /**
     * @notice Set performance fee
     * @dev Only callable by the contract admin.
     */
    function setPerformanceFee(uint256 _performanceFee) public onlyAdmin {
        require(
            _performanceFee <= MAX_PERFORMANCE_FEE,
            "performanceFee cannot be more than MAX_PERFORMANCE_FEE"
        );
        performanceFee = _performanceFee;
        emit NewPerformanceFee(performanceFee);
    }

    /**
     * @notice Set withdraw fee
     * @dev Only callable by the contract admin.
     */
    function setWithdrawFee(uint256 _withdrawFee) public onlyAdmin {
        require(
            _withdrawFee <= MAX_WITHDRAW_FEE,
            "withdrawFee cannot be more than MAX_WITHDRAW_FEE"
        );
        withdrawFee = _withdrawFee;
        emit NewWithdrawFee(withdrawFee);
    }

    /**
     * @notice Set overdue fee
     * @dev Only callable by the contract admin.
     */
    function setOverdueFee(uint256 _overdueFee) public onlyAdmin {
        require(
            _overdueFee <= MAX_OVERDUE_FEE,
            "overdueFee cannot be more than MAX_OVERDUE_FEE"
        );
        overdueFee = _overdueFee;
        emit NewOverdueFee(_overdueFee);
    }

    /**
     * @notice Set withdraw fee period
     * @dev Only callable by the contract admin.
     */
    function setWithdrawFeePeriod(uint256 _withdrawFeePeriod) public onlyAdmin {
        require(
            _withdrawFeePeriod <= MAX_WITHDRAW_FEE_PERIOD,
            "withdrawFeePeriod cannot be more than MAX_WITHDRAW_FEE_PERIOD"
        );
        withdrawFeePeriod = _withdrawFeePeriod;
        emit NewWithdrawFeePeriod(withdrawFeePeriod);
    }

    /**
     * @notice Set MAX_LOCK_DURATION
     * @dev Only callable by the contract admin.
     */
    function setMaxLockDuration(uint256 _maxLockDuration) public onlyAdmin {
        require(
            _maxLockDuration <= MAX_LOCK_DURATION_LIMIT,
            "MAX_LOCK_DURATION cannot be more than MAX_LOCK_DURATION_LIMIT"
        );
        MAX_LOCK_DURATION = _maxLockDuration;
        emit NewMaxLockDuration(_maxLockDuration);
    }

    /**
     * @notice Set DURATION_FACTOR
     * @dev Only callable by the contract admin.
     */
    function setDurationFactor(uint256 _durationFactor) public onlyAdmin {
        require(_durationFactor > 0, "DURATION_FACTOR cannot be zero");
        DURATION_FACTOR = _durationFactor;
        emit NewDurationFactor(_durationFactor);
    }

    /**
     * @notice Set DURATION_FACTOR_OVERDUE
     * @dev Only callable by the contract admin.
     */
    function setDurationFactorOverdue(
        uint256 _durationFactorOverdue
    ) public onlyAdmin {
        require(
            _durationFactorOverdue > 0,
            "DURATION_FACTOR_OVERDUE cannot be zero"
        );
        DURATION_FACTOR_OVERDUE = _durationFactorOverdue;
        emit NewDurationFactorOverdue(_durationFactorOverdue);
    }

    /**
     * @notice Set UNLOCK_FREE_DURATION
     * @dev Only callable by the contract admin.
     */
    function setUnlockFreeDuration(
        uint256 _unlockFreeDuration
    ) public onlyAdmin {
        require(_unlockFreeDuration > 0, "UNLOCK_FREE_DURATION cannot be zero");
        UNLOCK_FREE_DURATION = _unlockFreeDuration;
        emit NewUnlockFreeDuration(_unlockFreeDuration);
    }

    /**
     * @notice Set BOOST_WEIGHT
     * @dev Only callable by the contract admin.
     */
    function setBoostWeight(uint256 _boostWeight) public onlyAdmin {
        require(
            _boostWeight <= BOOST_WEIGHT_LIMIT,
            "BOOST_WEIGHT cannot be more than BOOST_WEIGHT_LIMIT"
        );
        BOOST_WEIGHT = _boostWeight;
        emit NewBoostWeight(_boostWeight);
    }

    /**
     * @notice Withdraw unexpected tokens sent to the BBC Pool
     */
    function inCaseTokensGetStuck(address _token) public onlyAdmin {
        require(
            _token != address(token),
            "Token cannot be same as deposit token"
        );

        uint256 amount = IERC20(_token).balanceOf(address(this));
        IERC20(_token).safeTransfer(msg.sender, amount);
    }

    /**
     * @notice Trigger stopped state
     * @dev Only possible when contract not paused.
     */
    function pause() public onlyAdmin whenNotPaused {
        _pause();
        emit Pause();
    }

    /**
     * @notice Return to normal state
     * @dev Only possible when contract is paused.
     */
    function unpause() public onlyAdmin whenPaused {
        _unpause();
        emit Unpause();
    }

    /**
     * @notice Calculate Performance fee.
     * @param _user: User address
     * @return Returns Performance fee.
     */
    function calculatePerformanceFee(
        address _user
    ) public view returns (uint256) {
        UserInfo storage user = userInfo[_user];
        if (
            user.shares > 0 && !user.locked && !freePerformanceFeeUsers[_user]
        ) {
            uint256 earnAmount = getProfit(_user);
            uint256 currentPerformanceFee = (earnAmount * performanceFee) /
                FEE_RATE_SCALE;
            return currentPerformanceFee;
        }
        return 0;
    }

    /**
     * @notice Calculate overdue fee.
     * @param _user: User address
     * @return Returns Overdue fee.
     */
    function calculateOverdueFee(address _user) public view returns (uint256) {
        UserInfo storage user = userInfo[_user];
        if (
            user.shares > 0 &&
            user.locked &&
            !freeOverdueFeeUsers[_user] &&
            ((user.lockEndTime + UNLOCK_FREE_DURATION) < block.timestamp)
        ) {
            uint256 earnAmount = getProfit(_user);
            uint256 overdueDuration = block.timestamp -
                user.lockEndTime -
                UNLOCK_FREE_DURATION;
            if (overdueDuration > DURATION_FACTOR_OVERDUE) {
                overdueDuration = DURATION_FACTOR_OVERDUE;
            }
            // Rates are calculated based on the user's overdue duration.
            uint256 overdueWeight = (overdueDuration * overdueFee) /
                DURATION_FACTOR_OVERDUE;
            uint256 currentOverdueFee = (earnAmount * overdueWeight) /
                PRECISION_FACTOR;
            return currentOverdueFee;
        }
        return 0;
    }

    /**
     * @notice Calculate Performance Fee Or Overdue Fee
     * @param _user: User address
     * @return Returns  Performance Fee Or Overdue Fee.
     */
    function calculatePerformanceFeeOrOverdueFee(
        address _user
    ) internal view returns (uint256) {
        return calculatePerformanceFee(_user) + calculateOverdueFee(_user);
    }

    /**
     * @notice Calculate withdraw fee.
     * @param _user: User address
     * @param _shares: Number of shares to withdraw
     * @return Returns Withdraw fee.
     */
    function calculateWithdrawFee(
        address _user, 
        uint256 _shares
    ) public view returns (uint256) {
        UserInfo storage user = userInfo[_user];
        if (user.shares < _shares) {
            _shares = user.shares;
        }
        if (!freeWithdrawFeeUsers[msg.sender] && !user.locked && (block.timestamp < user.lastDepositedTime + withdrawFeePeriod)) {
            uint256 pool = balanceOf() + calculateTotalPendingBBCRewards();
            uint256 sharesPercent = (_shares * PRECISION_FACTOR) / user.shares;
            uint256 currentTotalAmount = (pool * (user.shares)) /
                totalShares -
                user.userBoostedShare -
                calculatePerformanceFeeOrOverdueFee(_user);
            uint256 currentAmount = (currentTotalAmount * sharesPercent) / PRECISION_FACTOR;
            uint256 currentWithdrawFee = (currentAmount * withdrawFee) / FEE_RATE_SCALE;
            return currentWithdrawFee;
        }
        return 0;
    }

    /**
     * @notice Calculates the total pending rewards that can be harvested
     * @return Returns total pending bbc rewards
     */
    function calculateTotalPendingBBCRewards() public view returns (uint256) {
        uint256 amount = masterchefV2.pendingBBC(bbcPoolPID, address(this));
        return amount;
    }

    function getPricePerFullShare() public virtual view returns (uint256) {
        return
            totalShares == 0
                ? 1e18
                : ((balanceOf() + calculateTotalPendingBBCRewards()) * 1e18 / totalShares);
    }

    function getProfit(address _user) public virtual view returns (uint256) {
        UserInfo storage user = userInfo[_user];
        if (user.shares == 0) return 0;
        uint256 pool = balanceOf() + calculateTotalPendingBBCRewards();
        if (user.locked) {
            uint256 currentAmount = (pool * user.shares) /
                totalShares -
                user.userBoostedShare;
            return currentAmount - user.lockedAmount;
        }
        return
            (user.shares * pool) / totalShares - user.lastUserActionAmount;
    }

    /**
     * @notice Current pool available balance
     * @dev The contract puts 100% of the tokens to work.
     */
    function available() public view returns (uint256) {
        return token.balanceOf(address(this));
    }

    /**
     * @notice Calculates the total underlying bbcs
     * @dev It includes bbcs held by the contract and the boost debt amount.
     */
    function balanceOf() public view returns (uint256) {
        return token.balanceOf(address(this)) + totalBoostDebt;
    }
}

// File: contracts/pool/TokenPool.sol



// SPDX-License-Identifier: GPLv3
pragma solidity 0.8.19;

import "@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol";
import "./CakePool.sol";

contract TokenPool is CakePool {
    using SafeERC20 for IERC20;


    mapping(address => uint256) public userRewardDebt;
    mapping(address => uint256) public userRewardPending;

    uint256 public totalStakedAmount; // total stake amount.
    uint256 private bbcPerShare;
    uint8 private immutable tokenDecimals;

    /**
     * @notice Constructor
     * @param _token: Staking token contract
     * @param _masterchefV2: MasterChefV2 contract
     * @param _admin: address of the admin
     * @param _treasury: address of the treasury (collects fees)
     * @param _operator: address of operator
     * @param _pid: bbc pool ID in MasterChefV2
     */
    constructor(
        IERC20 _token,
        IMasterChefV2 _masterchefV2,
        address _admin,
        address _treasury,
        address _operator,
        uint256 _pid
    ) CakePool(_token, _masterchefV2, _admin, _treasury, _operator, _pid) {
        require(address(_token) != address(bbc), "Invalid token");
        tokenDecimals = IERC20Metadata(address(_token)).decimals();
        require(tokenDecimals<=18, "Unsupported decimals");
    }

    function toEther(uint256 _amount) internal view returns(uint256) {
        if(tokenDecimals < 18)
            return _amount * 10 ** (18 - tokenDecimals);
        else if(tokenDecimals > 18)
            return _amount / 10 ** (tokenDecimals - 18);
        return _amount;
    }
    
    function fromEther(uint256 _amount) internal view returns(uint256) {
        if(tokenDecimals < 18)
            return _amount / 10 ** (18 - tokenDecimals);
        else if(tokenDecimals > 18)
            return _amount * 10 ** (tokenDecimals - 18);
        return _amount;
    }

    /**
     * @notice Update user share when need to unlock or charges a fee.
     * @param _user: User address
     */
    function updateUserShare(address _user) internal override {
        UserInfo storage user = userInfo[_user];
        if (user.shares > 0) {
            if (user.locked) {
                // Calculate the user's current token amount and update related parameters.
                uint256 currentAmount = (balanceOf() * (user.shares)) /
                    totalShares -
                    user.userBoostedShare;
                totalBoostDebt -= user.userBoostedShare;
                user.userBoostedShare = 0;
                totalShares -= user.shares;
                //Charge a overdue fee after the free duration has expired.
                if (
                    !freeOverdueFeeUsers[_user] &&
                    ((user.lockEndTime + UNLOCK_FREE_DURATION) <
                        block.timestamp)
                ) {
                    uint256 earnAmount = userRewardPending[_user];
                    uint256 overdueDuration = block.timestamp -
                        user.lockEndTime -
                        UNLOCK_FREE_DURATION;
                    if (overdueDuration > DURATION_FACTOR_OVERDUE) {
                        overdueDuration = DURATION_FACTOR_OVERDUE;
                    }
                    // Rates are calculated based on the user's overdue duration.
                    uint256 overdueWeight = (overdueDuration * overdueFee) /
                        DURATION_FACTOR_OVERDUE;
                    uint256 currentOverdueFee = (earnAmount * overdueWeight) /
                        PRECISION_FACTOR;
                    uint256 feeHalf = currentOverdueFee / 2;
                    bbc.safeTransfer(treasury, feeHalf);
                    bbc.safeTransfer(
                        address(0xdead),
                        currentOverdueFee - feeHalf
                    );
                    userRewardPending[_user] -= currentOverdueFee;
                }
                // Recalculate the user's share.
                uint256 pool = balanceOf();
                uint256 currentShares;
                if (totalShares != 0) {
                    currentShares =
                        (currentAmount * totalShares) /
                        (pool - currentAmount);
                } else {
                    currentShares = currentAmount;
                }
                user.shares = currentShares;
                totalShares += currentShares;
                // After the lock duration, update related parameters.
                if (user.lockEndTime < block.timestamp) {
                    user.locked = false;
                    user.lockStartTime = 0;
                    user.lockEndTime = 0;
                    totalLockedAmount -= user.lockedAmount;
                    user.lockedAmount = 0;
                    emit Unlock(_user, currentAmount, block.timestamp);
                }
            } else if (!freePerformanceFeeUsers[_user]) {
                // Calculate Performance fee.
                uint256 earnAmount = userRewardPending[_user];
                uint256 currentPerformanceFee = (earnAmount *
                    performanceFee) / FEE_RATE_SCALE;
                if (currentPerformanceFee > 0) {
                    bbc.safeTransfer(treasury, currentPerformanceFee);
                    userRewardPending[_user] -= currentPerformanceFee;
                }
            }
        }
    }


    /**
     * @notice The operation of deposite.
     * @param _amount: number of tokens to deposit (in BBC)
     * @param _lockDuration: Token lock duration
     * @param _user: User address
     */
    function depositOperation(
        uint256 _amount,
        uint256 _lockDuration,
        address _user
    ) internal override {
        UserInfo storage user = userInfo[_user];
        if (user.shares == 0 || _amount > 0) {
            require(toEther(_amount) > MIN_DEPOSIT_AMOUNT, "Deposit amount must be greater than MIN_DEPOSIT_AMOUNT");
        }
        // Calculate the total lock duration and check whether the lock duration meets the conditions.
        uint256 totalLockDuration = _lockDuration;
        uint256 userLockEndTime = user.lockEndTime;
        if (userLockEndTime >= block.timestamp) {
            // Adding funds during the lock duration is equivalent to re-locking the position, needs to update some variables.
            if (_amount > 0) {
                user.lockStartTime = block.timestamp;
                totalLockedAmount -= user.lockedAmount;
                user.lockedAmount = 0;
            }
            totalLockDuration += userLockEndTime - user.lockStartTime;
        }
        require(
            _lockDuration == 0 || totalLockDuration >= MIN_LOCK_DURATION,
            "Minimum lock period is one week"
        );
        require(
            totalLockDuration <= MAX_LOCK_DURATION,
            "Maximum lock period exceeded"
        );

        // Harvest tokens from Masterchef.
        uint256 harvestedAmount = harvest();

        // Handle stock funds.
        if (totalShares == 0) {
            uint256 stockAmount = bbc.balanceOf(address(this));
            bbc.safeTransfer(treasury, stockAmount);
            harvestedAmount = 0;
        } else {
            bbcPerShare += (harvestedAmount * 1 ether) / totalShares;
            if (user.shares > 0) {
                userRewardPending[_user] +=
                    (bbcPerShare * user.shares) /
                    1 ether -
                    userRewardDebt[_user];
            }
        }

        // Update user share.
        updateUserShare(_user);

        // Update lock duration.
        if (_lockDuration > 0) {
            if (userLockEndTime < block.timestamp) {
                user.lockStartTime = block.timestamp;
                userLockEndTime = block.timestamp + _lockDuration;
            } else {
                userLockEndTime += _lockDuration;
            }
            user.locked = true;
            user.lockEndTime = userLockEndTime;
        }

        uint256 currentShares;
        uint256 currentAmount;
        uint256 userCurrentLockedBalance;
        uint256 pool = balanceOf();
        if (_amount > 0) {
            token.safeTransferFrom(_user, address(this), _amount);
            currentAmount = _amount;
        }

        // Calculate lock funds
        if (user.shares > 0 && user.locked) {
            userCurrentLockedBalance = (pool * user.shares) / totalShares;
            currentAmount += userCurrentLockedBalance;
            totalShares -= user.shares;
            user.shares = 0;

            // Update lock amount
            if (user.lockStartTime == block.timestamp) {
                user.lockedAmount = userCurrentLockedBalance;
                totalLockedAmount += user.lockedAmount;
            }
        }
        if (totalShares != 0) {
            currentShares =
                (currentAmount * totalShares) /
                (pool - userCurrentLockedBalance);
        } else {
            currentShares = currentAmount;
        }

        // Calculate the boost weight share.
        if (userLockEndTime > user.lockStartTime) {
            // Calculate boost share.
            uint256 boostWeight = ((userLockEndTime - user.lockStartTime) *
                BOOST_WEIGHT) / DURATION_FACTOR;
            uint256 boostShares = (boostWeight * currentShares) /
                PRECISION_FACTOR;
            currentShares += boostShares;
            user.shares += currentShares;

            // Calculate boost share , the user only enjoys the reward, so the principal needs to be recorded as a debt.
            uint256 userBoostedShare = (boostWeight * currentAmount) /
                PRECISION_FACTOR;
            user.userBoostedShare += userBoostedShare;
            totalBoostDebt += userBoostedShare;

            // Update lock amount.
            user.lockedAmount += _amount;
            totalLockedAmount += _amount;

            emit Lock(
                _user,
                user.lockedAmount,
                user.shares,
                (userLockEndTime - user.lockStartTime),
                block.timestamp
            );
        } else {
            user.shares += currentShares;
        }

        if (_amount > 0 || _lockDuration > 0) {
            user.lastDepositedTime = block.timestamp;
        }
        totalShares += currentShares;

        user.lastUserActionAmount =
            (user.shares * balanceOf()) /
            totalShares -
            user.userBoostedShare;

        user.lastUserActionTime = block.timestamp;

        userRewardDebt[_user] = (bbcPerShare * user.shares) / 1 ether;
        totalStakedAmount += _amount;

        emit Deposit(
            _user,
            _amount,
            currentShares,
            _lockDuration,
            block.timestamp
        );
    }

    /**
     * @notice The operation of withdraw.
     * @param _shares: Number of shares to withdraw
     * @param _amount: Number of amount to withdraw
     */
    function withdrawOperation(uint256 _shares, uint256 _amount) internal override {
        UserInfo storage user = userInfo[msg.sender];
        if(_shares==0 && _amount > 0)
            require(toEther(_amount) > MIN_WITHDRAW_AMOUNT, "Withdraw amount must be greater than MIN_WITHDRAW_AMOUNT");
        require(_shares <= user.shares, "Withdraw amount exceeds balance");
        require(user.lockEndTime < block.timestamp, "Still in lock");

        // Calculate the percent of withdraw shares, when unlocking or calculating the Performance fee, the shares will be updated.
        uint256 currentShare = _shares;
        uint256 sharesPercent = (_shares * PRECISION_FACTOR_SHARE) /
            user.shares;

        // Harvest token from MasterchefV2.
        uint256 harvestedAmount = harvest();

        if (totalShares > 0) {
            bbcPerShare += (harvestedAmount * 1 ether) / totalShares;
            if (user.shares > 0) {
                userRewardPending[msg.sender] +=
                    (bbcPerShare * user.shares) /
                    1 ether -
                    userRewardDebt[msg.sender];
            }
        }

        // Update user share.
        updateUserShare(msg.sender);

        if (_shares == 0 && _amount > 0) {
            uint256 pool = balanceOf();
            currentShare = (_amount * totalShares) / pool; // Calculate equivalent shares
            if (currentShare > user.shares) {
                currentShare = user.shares;
            }
        } else {
            currentShare =
                (sharesPercent * user.shares) /
                PRECISION_FACTOR_SHARE;
        }
        
        uint256 currentAmount = (balanceOf() * currentShare) / totalShares;
        user.shares -= currentShare;
        totalShares -= currentShare;

        uint256 senderRewardPending = userRewardPending[msg.sender];
        if (user.shares == 0 && senderRewardPending > 0) {
            bbc.safeTransfer(msg.sender, senderRewardPending);
            userRewardPending[msg.sender] = 0;
        }
        totalStakedAmount -= currentAmount;

        // Calculate withdraw fee
        if (
            !freeWithdrawFeeUsers[msg.sender] &&
            (block.timestamp < user.lastDepositedTime + withdrawFeePeriod)
        ) {
            uint256 currentWithdrawFee = (currentAmount * withdrawFee) /
                FEE_RATE_SCALE;
            token.safeTransfer(treasury, currentWithdrawFee);
            currentAmount -= currentWithdrawFee;
        }
        token.safeTransfer(msg.sender, currentAmount);

        if (user.shares > 0) {
            user.lastUserActionAmount =
                (user.shares * balanceOf()) /
                totalShares;
        } else {
            user.lastUserActionAmount = 0;
        }

        user.lastUserActionTime = block.timestamp;
        userRewardDebt[msg.sender] = (bbcPerShare * user.shares) / 1 ether;

        emit Withdraw(msg.sender, currentAmount, currentShare);
    }

    function claim() public nonReentrant returns (uint256) {
        UserInfo storage user = userInfo[msg.sender];
        if (!user.locked) {
            uint256 harvestedAmount = harvest();
            bbcPerShare += (harvestedAmount * 1 ether) / totalShares;
            uint256 currentBBCAmount = userRewardPending[msg.sender] +
                (bbcPerShare * user.shares) /
                1 ether -
                userRewardDebt[msg.sender];
            if (currentBBCAmount > 0) {
                userRewardPending[msg.sender] = 0;

                if (!freePerformanceFeeUsers[msg.sender]) {
                    uint256 currentPerformanceFee = (currentBBCAmount *
                        performanceFee) / FEE_RATE_SCALE;

                    if (currentPerformanceFee > 0) {
                        currentBBCAmount -= currentPerformanceFee;
                        bbc.safeTransfer(treasury, currentPerformanceFee);
                    }
                }
                bbc.safeTransfer(msg.sender, currentBBCAmount);
            }
            userRewardDebt[msg.sender] =
                (bbcPerShare * user.shares) /
                1 ether;
            return currentBBCAmount;
        }
        return 0;
    }


    function getPricePerFullShare() public override view returns (uint256) {
        return
            totalShares == 0
                ? 1e18
                : ((bbc.balanceOf(address(this)) + calculateTotalPendingBBCRewards()) * 1e18 / totalShares);
    }

    function getProfit(address _user) public override view returns (uint256) {
        UserInfo storage user = userInfo[_user];
        if (user.shares == 0) return 0;
        return
            (calculateTotalPendingBBCRewards() * user.shares) /
            totalShares +
            userRewardPending[_user] +
            (bbcPerShare * user.shares) /
            1 ether -
            userRewardDebt[_user];
    }
}