// File: autocompound.sol



/**
 *Submitted for verification at BscScan.com on 2021-04-29
 */

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

// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <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 GSN 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 payable) {
    return msg.sender;
  }

  function _msgData() internal view virtual returns (bytes memory) {
    this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
    return msg.data;
  }
}

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

pragma solidity >=0.6.0 <0.8.0;

/**
 * @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() internal {
    address msgSender = _msgSender();
    _owner = msgSender;
    emit OwnershipTransferred(address(0), msgSender);
  }

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

  /**
   * @dev Throws if called by any account other than the owner.
   */
  modifier onlyOwner() {
    require(owner() == _msgSender(), "Ownable: caller is not the owner");
    _;
  }

  /**
   * @dev Leaves the contract without owner. It will not be possible to call
   * `onlyOwner` functions anymore. Can only be called by the current owner.
   *
   * NOTE: Renouncing ownership will leave the contract without an owner,
   * thereby removing any functionality that is only available to the owner.
   */
  function renounceOwnership() public virtual onlyOwner {
    emit OwnershipTransferred(_owner, address(0));
    _owner = 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");
    emit OwnershipTransferred(_owner, newOwner);
    _owner = newOwner;
  }
}

// File: @openzeppelin/contracts/math/SafeMath.sol

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
  /**
   * @dev Returns the addition of two unsigned integers, with an overflow flag.
   *
   * _Available since v3.4._
   */
  function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
    uint256 c = a + b;
    if (c < a) return (false, 0);
    return (true, c);
  }

  /**
   * @dev Returns the substraction of two unsigned integers, with an overflow flag.
   *
   * _Available since v3.4._
   */
  function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
    if (b > a) return (false, 0);
    return (true, a - b);
  }

  /**
   * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
   *
   * _Available since v3.4._
   */
  function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
    // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
    // benefit is lost if 'b' is also tested.
    // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
    if (a == 0) return (true, 0);
    uint256 c = a * b;
    if (c / a != b) return (false, 0);
    return (true, c);
  }

  /**
   * @dev Returns the division of two unsigned integers, with a division by zero flag.
   *
   * _Available since v3.4._
   */
  function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
    if (b == 0) return (false, 0);
    return (true, a / b);
  }

  /**
   * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
   *
   * _Available since v3.4._
   */
  function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
    if (b == 0) return (false, 0);
    return (true, a % b);
  }

  /**
   * @dev Returns the addition of two unsigned integers, reverting on
   * overflow.
   *
   * Counterpart to Solidity's `+` operator.
   *
   * Requirements:
   *
   * - Addition cannot overflow.
   */
  function add(uint256 a, uint256 b) internal pure returns (uint256) {
    uint256 c = a + b;
    require(c >= a, "SafeMath: addition overflow");
    return c;
  }

  /**
   * @dev Returns the subtraction of two unsigned integers, reverting on
   * overflow (when the result is negative).
   *
   * Counterpart to Solidity's `-` operator.
   *
   * Requirements:
   *
   * - Subtraction cannot overflow.
   */
  function sub(uint256 a, uint256 b) internal pure returns (uint256) {
    require(b <= a, "SafeMath: subtraction overflow");
    return a - b;
  }

  /**
   * @dev Returns the multiplication of two unsigned integers, reverting on
   * overflow.
   *
   * Counterpart to Solidity's `*` operator.
   *
   * Requirements:
   *
   * - Multiplication cannot overflow.
   */
  function mul(uint256 a, uint256 b) internal pure returns (uint256) {
    if (a == 0) return 0;
    uint256 c = a * b;
    require(c / a == b, "SafeMath: multiplication overflow");
    return c;
  }

  /**
   * @dev Returns the integer division of two unsigned integers, reverting on
   * division by zero. The result is rounded towards zero.
   *
   * Counterpart to Solidity's `/` operator. Note: this function uses a
   * `revert` opcode (which leaves remaining gas untouched) while Solidity
   * uses an invalid opcode to revert (consuming all remaining gas).
   *
   * Requirements:
   *
   * - The divisor cannot be zero.
   */
  function div(uint256 a, uint256 b) internal pure returns (uint256) {
    require(b > 0, "SafeMath: division by zero");
    return a / b;
  }

  /**
   * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
   * reverting when dividing by zero.
   *
   * Counterpart to Solidity's `%` operator. This function uses a `revert`
   * opcode (which leaves remaining gas untouched) while Solidity uses an
   * invalid opcode to revert (consuming all remaining gas).
   *
   * Requirements:
   *
   * - The divisor cannot be zero.
   */
  function mod(uint256 a, uint256 b) internal pure returns (uint256) {
    require(b > 0, "SafeMath: modulo by zero");
    return a % b;
  }

  /**
   * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
   * overflow (when the result is negative).
   *
   * CAUTION: This function is deprecated because it requires allocating memory for the error
   * message unnecessarily. For custom revert reasons use {trySub}.
   *
   * Counterpart to Solidity's `-` operator.
   *
   * Requirements:
   *
   * - Subtraction cannot overflow.
   */
  function sub(
    uint256 a,
    uint256 b,
    string memory errorMessage
  ) internal pure returns (uint256) {
    require(b <= a, errorMessage);
    return a - b;
  }

  /**
   * @dev Returns the integer division of two unsigned integers, reverting with custom message on
   * division by zero. The result is rounded towards zero.
   *
   * CAUTION: This function is deprecated because it requires allocating memory for the error
   * message unnecessarily. For custom revert reasons use {tryDiv}.
   *
   * Counterpart to Solidity's `/` operator. Note: this function uses a
   * `revert` opcode (which leaves remaining gas untouched) while Solidity
   * uses an invalid opcode to revert (consuming all remaining gas).
   *
   * Requirements:
   *
   * - The divisor cannot be zero.
   */
  function div(
    uint256 a,
    uint256 b,
    string memory errorMessage
  ) internal pure returns (uint256) {
    require(b > 0, errorMessage);
    return a / b;
  }

  /**
   * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
   * reverting with custom message when dividing by zero.
   *
   * CAUTION: This function is deprecated because it requires allocating memory for the error
   * message unnecessarily. For custom revert reasons use {tryMod}.
   *
   * Counterpart to Solidity's `%` operator. This function uses a `revert`
   * opcode (which leaves remaining gas untouched) while Solidity uses an
   * invalid opcode to revert (consuming all remaining gas).
   *
   * Requirements:
   *
   * - The divisor cannot be zero.
   */
  function mod(
    uint256 a,
    uint256 b,
    string memory errorMessage
  ) internal pure returns (uint256) {
    require(b > 0, errorMessage);
    return a % b;
  }
}

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

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
  /**
   * @dev Returns the amount of tokens in existence.
   */
  function totalSupply() external view returns (uint256);

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

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

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

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

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

  /**
   * @dev Emitted when `value` tokens are moved from one account (`from`) to
   * another (`to`).
   *
   * Note that `value` may be zero.
   */
  event Transfer(address indexed from, address indexed to, uint256 value);

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

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

pragma solidity >=0.6.2 <0.8.0;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
  /**
   * @dev Returns true if `account` is a contract.
   *
   * [IMPORTANT]
   * ====
   * It is unsafe to assume that an address for which this function returns
   * false is an externally-owned account (EOA) and not a contract.
   *
   * Among others, `isContract` will return false for the following
   * types of addresses:
   *
   *  - an externally-owned account
   *  - a contract in construction
   *  - an address where a contract will be created
   *  - an address where a contract lived, but was destroyed
   * ====
   */
  function isContract(address account) internal view returns (bool) {
    // This method relies on extcodesize, which returns 0 for contracts in
    // construction, since the code is only stored at the end of the
    // constructor execution.

    uint256 size;
    // solhint-disable-next-line no-inline-assembly
    assembly {
      size := extcodesize(account)
    }
    return size > 0;
  }

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

    // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
    (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");

    // solhint-disable-next-line avoid-low-level-calls
    (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");

    // solhint-disable-next-line avoid-low-level-calls
    (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");

    // solhint-disable-next-line avoid-low-level-calls
    (bool success, bytes memory returndata) = target.delegatecall(data);
    return _verifyCallResult(success, returndata, errorMessage);
  }

  function _verifyCallResult(
    bool success,
    bytes memory returndata,
    string memory errorMessage
  ) private 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

        // solhint-disable-next-line no-inline-assembly
        assembly {
          let returndata_size := mload(returndata)
          revert(add(32, returndata), returndata_size)
        }
      } else {
        revert(errorMessage);
      }
    }
  }
}

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

pragma solidity >=0.6.0 <0.8.0;

/**
 * @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 SafeMath for uint256;
  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'
    // solhint-disable-next-line max-line-length
    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).add(value);
    _callOptionalReturn(
      token,
      abi.encodeWithSelector(token.approve.selector, spender, newAllowance)
    );
  }

  function safeDecreaseAllowance(
    IERC20 token,
    address spender,
    uint256 value
  ) internal {
    uint256 newAllowance = token.allowance(address(this), spender).sub(
      value,
      "SafeERC20: decreased allowance below zero"
    );
    _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
      // solhint-disable-next-line max-line-length
      require(
        abi.decode(returndata, (bool)),
        "SafeERC20: ERC20 operation did not succeed"
      );
    }
  }
}

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

pragma solidity >=0.6.0 <0.8.0;

/**
 * @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() internal {
    _paused = false;
  }

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

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

  /**
   * @dev Modifier to make a function callable only when the contract is paused.
   *
   * Requirements:
   *
   * - The contract must be paused.
   */
  modifier whenPaused() {
    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: contracts/interfaces/IMasterChef.sol

pragma solidity 0.6.12;

interface IMasterChef {
  function deposit(uint256 _amount) external;

  function withdraw(uint256 _amount) external;

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

  function emergencyWithdraw() external;
}

// File: contracts/CakeVault.sol

pragma solidity 0.6.12;

contract CakeVault is Ownable, Pausable {
  using SafeERC20 for IERC20;
  using SafeMath for uint256;

  struct UserInfo {
    uint256 shares; // number of shares for a user
    uint256 lastDepositedTime; // keeps track of deposited time for potential penalty
    uint256 cakeAtLastUserAction; // keeps track of cake deposited at the last user action
    uint256 lastUserActionTime; // keeps track of the last user action time
  }

  IERC20 public immutable token; // Cake token

  IMasterChef public immutable masterchef;

  mapping(address => UserInfo) public userInfo;

  uint256 public totalShares;
  uint256 public lastHarvestedTime;
  address public admin;
  address public treasury;

  uint256 public constant MAX_PERFORMANCE_FEE = 9999; // 5%
  uint256 public constant MAX_CALL_FEE = 9999; // 1%
  uint256 public constant MAX_WITHDRAW_FEE = 9999; // 1%
  uint256 public MAX_WITHDRAW_FEE_PERIOD = 365 days; // 3 days

  uint256 public performanceFee = 200; // 2%
  uint256 public callFee = 300; // 3%
  uint256 public withdrawFee; // 100 = 1%
  uint256 public withdrawFeePeriod; //  ex : 3 days

  event Deposit(
    address indexed sender,
    uint256 amount,
    uint256 shares,
    uint256 lastDepositedTime
  );
  event Withdraw(address indexed sender, uint256 amount, uint256 shares);
  event Harvest(
    address indexed sender,
    uint256 performanceFee,
    uint256 callFee
  );
  event Pause();
  event Unpause();
  event RescueTokens(
    address indexed user,
    address indexed token,
    uint256 amount
  );

  /**
   * @notice Constructor
   * @param _token: Cake token contract
   * @param _masterchef: MasterChef contract
   * @param _admin: address of the admin
   * @param _treasury: address of the treasury (collects fees)
   */
  constructor(
    IERC20 _token, // token staked (e.g eterna)
    IMasterChef _masterchef, // staking contract
    address _admin, // who will manage the contract
    address _treasury, // wallet which will skim rewards
    uint256 _withdrawFee,
    uint256 _withdrawFeePeriod
  ) public {
    token = _token;
    masterchef = _masterchef;
    admin = _admin;
    treasury = _treasury;
    withdrawFee = _withdrawFee;
    withdrawFeePeriod = _withdrawFeePeriod;

    // Infinite approve
    IERC20(_token).safeApprove(address(_masterchef), uint256(-1));
  }

  /**
   * @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 a contract or a proxy
   */
  modifier notContract() {
    require(!_isContract(msg.sender), "contract not allowed");
    require(msg.sender == tx.origin, "proxy contract not allowed");
    _;
  }

  /**
   * @notice Deposits funds into the Cake Vault
   * @dev Only possible when contract not paused.
   * @param _amount: number of tokens to deposit (in CAKE)
   */
  function deposit(uint256 _amount) external whenNotPaused notContract {
    require(_amount > 0, "Nothing to deposit");

    uint256 pool = balanceOf();
    token.safeTransferFrom(msg.sender, address(this), _amount);
    uint256 currentShares = 0;
    if (totalShares != 0) {
      currentShares = (_amount.mul(totalShares)).div(pool);
    } else {
      currentShares = _amount;
    }
    UserInfo storage user = userInfo[msg.sender];

    user.shares = user.shares.add(currentShares);
    user.lastDepositedTime = block.timestamp;

    totalShares = totalShares.add(currentShares);

    user.cakeAtLastUserAction = user.shares.mul(balanceOf()).div(totalShares);
    user.lastUserActionTime = block.timestamp;

    _earn();

    emit Deposit(msg.sender, _amount, currentShares, block.timestamp);
  }

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

  /**
   * @notice Reinvests CAKE tokens into MasterChef
   * @dev Only possible when contract not paused.
   */
  function harvest() external notContract whenNotPaused {
    IMasterChef(masterchef).withdraw(0);

    uint256 bal = available();
    uint256 currentPerformanceFee = bal.mul(performanceFee).div(10000);
    token.safeTransfer(treasury, currentPerformanceFee);

    uint256 currentCallFee = bal.mul(callFee).div(10000);
    token.safeTransfer(msg.sender, currentCallFee);

    _earn();

    lastHarvestedTime = block.timestamp;

    emit Harvest(msg.sender, currentPerformanceFee, currentCallFee);
  }

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

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

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

  /**
   * @notice Sets call fee
   * @dev Only callable by the contract admin.
   */
  function setCallFee(uint256 _callFee) external onlyAdmin {
    require(
      _callFee <= MAX_CALL_FEE,
      "callFee cannot be more than MAX_CALL_FEE"
    );
    callFee = _callFee;
  }

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

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

  /**
   * @notice Withdraws from MasterChef to Vault without caring about rewards.
   * @dev EMERGENCY ONLY. Only callable by the contract admin.
   */
  function emergencyWithdraw() external onlyAdmin {
    IMasterChef(masterchef).emergencyWithdraw();
  }

  /**
   * @notice Withdraw unexpected tokens sent to the Cake Vault
   */
  function inCaseTokensGetStuck(address _token) external onlyAdmin {
    uint256 amount = IERC20(_token).balanceOf(address(this));
    IERC20(_token).safeTransfer(msg.sender, amount);
  }

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

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

  /**
   * @notice Calculates the price per share
   */
  function getPricePerFullShare() external view returns (uint256) {
    return totalShares == 0 ? 1e18 : balanceOf().mul(1e18).div(totalShares);
  }

  /**
   * @notice Withdraws from funds from the Cake Vault
   * @param _shares: Number of shares to withdraw
   */
  function withdraw(uint256 _shares) public notContract {
    UserInfo storage user = userInfo[msg.sender];
    require(_shares > 0, "Nothing to withdraw");
    require(_shares <= user.shares, "Withdraw amount exceeds balance");

    uint256 currentAmount = (balanceOf().mul(_shares)).div(totalShares);
    user.shares = user.shares.sub(_shares);
    totalShares = totalShares.sub(_shares);

    uint256 bal = available();
    if (bal < currentAmount) {
      uint256 balWithdraw = currentAmount.sub(bal);
      IMasterChef(masterchef).withdraw(balWithdraw);
      uint256 balAfter = available();
      uint256 diff = balAfter.sub(bal);
      if (diff < balWithdraw) {
        currentAmount = bal.add(diff);
      }
    }

    if (block.timestamp < user.lastDepositedTime.add(withdrawFeePeriod)) {
      uint256 currentWithdrawFee = currentAmount.mul(withdrawFee).div(10000);
      token.safeTransfer(treasury, currentWithdrawFee);
      currentAmount = currentAmount.sub(currentWithdrawFee);
    }

    if (user.shares > 0) {
      user.cakeAtLastUserAction = user.shares.mul(balanceOf()).div(totalShares);
    } else {
      user.cakeAtLastUserAction = 0;
    }

    user.lastUserActionTime = block.timestamp;

    token.safeTransfer(msg.sender, currentAmount);

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

  /**
   * @notice Custom logic for how much the vault allows to be borrowed
   * @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 tokens
   * @dev It includes tokens held by the contract and held in MasterChef
   */
  function balanceOf() public view returns (uint256) {
    (uint256 amount, ) = IMasterChef(masterchef).userInfo(address(this));
    return token.balanceOf(address(this)).add(amount);
  }

  /**
   * @notice Deposits tokens into MasterChef to earn staking rewards
   */
  function _earn() internal {
    uint256 bal = available();
    if (bal > 0) {
      IMasterChef(masterchef).deposit(bal);
    }
  }

  function rescueToken(
    address token,
    address addressForReceive,
    uint256 amount
  ) external onlyOwner {
    IERC20(token).safeTransfer(addressForReceive, amount);
    emit RescueTokens(msg.sender, token, amount);
  }

  /**
   * @notice Checks if address is a contract
   * @dev It prevents contract from being targetted
   */
  function _isContract(address addr) internal view returns (bool) {
    uint256 size;
    assembly {
      size := extcodesize(addr)
    }
    return size > 0;
  }
}