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

pragma solidity ^0.5.0;

/**
 * @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, 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) {
    return sub(a, b, "SafeMath: subtraction overflow");
  }

  /**
   * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
   * overflow (when the result is negative).
   *
   * Counterpart to Solidity's `-` operator.
   *
   * Requirements:
   * - Subtraction cannot overflow.
   *
   * _Available since v2.4.0._
   */
  function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
    require(b <= a, errorMessage);
    uint256 c = a - b;

    return c;
  }

  /**
   * @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) {
    // 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 0;
    }

    uint256 c = a * b;
    require(c / a == b, "SafeMath: multiplication overflow");

    return c;
  }

  /**
   * @dev Returns the integer division of two unsigned integers. Reverts 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) {
    return div(a, b, "SafeMath: division by zero");
  }

  /**
   * @dev Returns the integer division of two unsigned integers. Reverts with custom message 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.
   *
   * _Available since v2.4.0._
   */
  function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
    // Solidity only automatically asserts when dividing by 0
    require(b > 0, errorMessage);
    uint256 c = a / b;
    // assert(a == b * c + a % b); // There is no case in which this doesn't hold

    return c;
  }

  /**
   * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
   * Reverts 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) {
    return mod(a, b, "SafeMath: modulo by zero");
  }

  /**
   * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
   * Reverts with custom message 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.
   *
   * _Available since v2.4.0._
   */
  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 ^0.5.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP. Does not include
 * the optional functions; to access them see {ERC20Detailed}.
 */
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 ^0.5.5;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
  /**
   * @dev Returns true if `account` is a contract.
   *
   * This test is non-exhaustive, and there may be false-negatives: during the
   * execution of a contract's constructor, its address will be reported as
   * not containing 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.
   */
  function isContract(address account) internal view returns (bool) {
    // This method relies in extcodesize, which returns 0 for contracts in
    // construction, since the code is only stored at the end of the
    // constructor execution.

    // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
    // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
    // for accounts without code, i.e. `keccak256('')`
    bytes32 codehash;
    bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
    // solhint-disable-next-line no-inline-assembly
    assembly { codehash := extcodehash(account) }
    return (codehash != 0x0 && codehash != accountHash);
  }

  /**
   * @dev Converts an `address` into `address payable`. Note that this is
   * simply a type cast: the actual underlying value is not changed.
   *
   * _Available since v2.4.0._
   */
  function toPayable(address account) internal pure returns (address payable) {
    return address(uint160(account));
  }

  /**
   * @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].
   *
   * _Available since v2.4.0._
   */
  function sendValue(address payable recipient, uint256 amount) internal {
    require(address(this).balance >= amount, "Address: insufficient balance");

    // solhint-disable-next-line avoid-call-value
    (bool success, ) = recipient.call.value(amount)("");
    require(success, "Address: unable to send value, recipient may have reverted");
  }
}

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

pragma solidity ^0.5.0;




/**
 * @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 ERC20;` 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));
  }

  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.

    // A Solidity high level call has three parts:
    //  1. The target address is checked to verify it contains contract code
    //  2. The call itself is made, and success asserted
    //  3. The return value is decoded, which in turn checks the size of the returned data.
    // solhint-disable-next-line max-line-length
    require(address(token).isContract(), "SafeERC20: call to non-contract");

    // solhint-disable-next-line avoid-low-level-calls
    (bool success, bytes memory returndata) = address(token).call(data);
    require(success, "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");
    }
  }
}


contract Storage {

  address public governance;
  address public controller;

  constructor() public {
    governance = msg.sender;
  }

  modifier onlyGovernance() {
    require(isGovernance(msg.sender), "Not governance");
    _;
  }

  function setGovernance(address _governance) public onlyGovernance {
    require(_governance != address(0), "new governance shouldn't be empty");
    governance = _governance;
  }

  function setController(address _controller) public onlyGovernance {
    require(_controller != address(0), "new controller shouldn't be empty");
    controller = _controller;
  }

  function isGovernance(address account) public view returns (bool) {
    return account == governance;
  }

  function isController(address account) public view returns (bool) {
    return account == controller;
  }
}

contract Governable {

  Storage public store;

  constructor(address _store) public {
    require(_store != address(0), "new storage shouldn't be empty");
    store = Storage(_store);
  }

  modifier onlyGovernance() {
    require(store.isGovernance(msg.sender), "Not governance");
    _;
  }

  function setStorage(address _store) public onlyGovernance {
    require(_store != address(0), "new storage shouldn't be empty");
    store = Storage(_store);
  }

  function governance() public view returns (address) {
    return store.governance();
  }
}

contract Controllable is Governable {

  constructor(address _storage) Governable(_storage) public {
  }

  modifier onlyController() {
    require(store.isController(msg.sender), "Not a controller");
    _;
  }

  modifier onlyControllerOrGovernance(){
    require((store.isController(msg.sender) || store.isGovernance(msg.sender)),
      "The caller must be controller or governance");
    _;
  }

  function controller() public view returns (address) {
    return store.controller();
  }
}


interface IMintRewardPool {
  function balanceOf(address account) external view returns (uint256);
  function exit() external;
  function stake(uint256 amount) external;
  function earned(address account) external view returns (uint256);
}


interface IController {
  // [Grey list]
  // An EOA can safely interact with the system no matter what.
  // If you're using Metamask, you're using an EOA.
  // Only smart contracts may be affected by this grey list.
  //
  // This contract will not be able to ban any EOA from the system
  // even if an EOA is being added to the greyList, he/she will still be able
  // to interact with the whole system as if nothing happened.
  // Only smart contracts will be affected by being added to the greyList.
  // This grey list is only used in Vault.sol, see the code there for reference
  function greyList(address _target) external view returns(bool);

  function addVaultAndStrategy(address _vault, address _strategy) external;
  function doHardWork(address _vault) external;
  function hasVault(address _vault) external returns(bool);

  function salvage(address _token, uint256 amount) external;
  function salvageStrategy(address _strategy, address _token, uint256 amount) external;

  function notifyFee(address _underlying, uint256 fee) external;
  function profitSharingNumerator() external view returns (uint256);
  function profitSharingDenominator() external view returns (uint256);
}



contract AutoStake is Controllable {

  using SafeERC20 for IERC20;
  using SafeMath for uint256;

  IMintRewardPool public rewardPool;
  IERC20 public lpToken;
  uint256 public unit = 1e18;
  uint256 public valuePerShare = unit;
  uint256 public totalShares = 0;
  uint256 public totalValue = 0;
  mapping(address => uint256) public share;

  event Staked(address indexed user, uint256 amount, uint256 sharesIssued, uint256 oldShareVaule, uint256 newShareValue, uint256 balanceOf);
  event Withdrawn(address indexed user, uint256 total);

  constructor(address _storage, address pool, address token) public
  Controllable(_storage)
  {
    rewardPool = IMintRewardPool(pool);
    lpToken = IERC20(token);
  }

  function refreshAutoStake() external {
    exitRewardPool();
    updateValuePerShare();
    restakeIntoRewardPool();
  }

  function stake(uint256 amount) public {
    exitRewardPool();
    updateValuePerShare();

    // now we can issue shares
    lpToken.safeTransferFrom(msg.sender, address(this), amount);
    uint256 sharesToIssue = amount.mul(unit).div(valuePerShare);
    totalShares = totalShares.add(sharesToIssue);
    share[msg.sender] = share[msg.sender].add(sharesToIssue);

    uint256 oldValuePerShare = valuePerShare;

    // Rate needs to be updated here, otherwise the valuePerShare would be incorrect.
    updateValuePerShare();

    emit Staked(msg.sender, amount, sharesToIssue, oldValuePerShare, valuePerShare, balanceOf(msg.sender));

    restakeIntoRewardPool();
  }

  function exit() public {
    exitRewardPool();
    updateValuePerShare();

    // now we can transfer funds and burn shares
    uint256 toTransfer = balanceOf(msg.sender);
    lpToken.safeTransfer(msg.sender, toTransfer);
    totalShares = totalShares.sub(share[msg.sender]);
    share[msg.sender] = 0;
    emit Withdrawn(msg.sender, toTransfer);
    // Rate needs to be updated here, otherwise the valuePerShare would be incorrect.
    updateValuePerShare();

    restakeIntoRewardPool();
  }

  function balanceOf(address who) public view returns(uint256) {
    return valuePerShare.mul(share[who]).div(unit);
  }

  function earned(address account) external view returns (uint256) {
    if (totalShares == 0) {
      return 0;
    }
    uint256 totalBalance = rewardPool.balanceOf(address(this));
    uint256 totalEarn = rewardPool.earned(address(this));
    uint256 perShare = totalBalance.add(totalEarn).mul(unit).div(totalShares);

    return perShare.mul(share[account]).div(unit);
  }

  function updateValuePerShare() internal {
    if (totalShares == 0) {
      totalValue = 0;
      valuePerShare = unit;
    } else {
      totalValue = lpToken.balanceOf(address(this));
      valuePerShare = totalValue.mul(unit).div(totalShares);
    }
  }

  function exitRewardPool() internal {
    if(rewardPool.balanceOf(address(this)) != 0){
      // exit and do accounting first
      rewardPool.exit();
    }
  }

  function restakeIntoRewardPool() internal {
    if(lpToken.balanceOf(address(this)) != 0){
      // stake back to the pool
      lpToken.safeApprove(address(rewardPool), 0);
      lpToken.safeApprove(address(rewardPool), lpToken.balanceOf(address(this)));
      rewardPool.stake(lpToken.balanceOf(address(this)));
    }
  }
}

{
  "compilationTarget": {
    "AutoStake.sol": "AutoStake"
  },
  "evmVersion": "petersburg",
  "libraries": {},
  "optimizer": {
    "enabled": true,
    "runs": 200
  },
  "remappings": []
}