pragma solidity ^0.4.24;

// File: zeppelin-solidity/contracts/ownership/Ownable.sol

/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
  address public owner;


  event OwnershipRenounced(address indexed previousOwner);
  event OwnershipTransferred(
    address indexed previousOwner,
    address indexed newOwner
  );


  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */
  constructor() public {
    owner = msg.sender;
  }

  /**
   * @dev Throws if called by any account other than the owner.
   */
  modifier onlyOwner() {
    require(msg.sender == owner);
    _;
  }

  /**
   * @dev Allows the current owner to relinquish control of the contract.
   * @notice Renouncing to ownership will leave the contract without an owner.
   * It will not be possible to call the functions with the `onlyOwner`
   * modifier anymore.
   */
  function renounceOwnership() public onlyOwner {
    emit OwnershipRenounced(owner);
    owner = address(0);
  }

  /**
   * @dev Allows the current owner to transfer control of the contract to a newOwner.
   * @param _newOwner The address to transfer ownership to.
   */
  function transferOwnership(address _newOwner) public onlyOwner {
    _transferOwnership(_newOwner);
  }

  /**
   * @dev Transfers control of the contract to a newOwner.
   * @param _newOwner The address to transfer ownership to.
   */
  function _transferOwnership(address _newOwner) internal {
    require(_newOwner != address(0));
    emit OwnershipTransferred(owner, _newOwner);
    owner = _newOwner;
  }
}

// File: zeppelin-solidity/contracts/math/SafeMath.sol

/**
 * @title SafeMath
 * @dev Math operations with safety checks that throw on error
 */
library SafeMath {

  /**
  * @dev Multiplies two numbers, throws on overflow.
  */
  function mul(uint256 _a, uint256 _b) internal pure returns (uint256 c) {
    // Gas optimization: this is cheaper than asserting 'a' not being zero, but the
    // benefit is lost if 'b' is also tested.
    // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
    if (_a == 0) {
      return 0;
    }

    c = _a * _b;
    assert(c / _a == _b);
    return c;
  }

  /**
  * @dev Integer division of two numbers, truncating the quotient.
  */
  function div(uint256 _a, uint256 _b) internal pure returns (uint256) {
    // assert(_b > 0); // Solidity automatically throws when dividing by 0
    // uint256 c = _a / _b;
    // assert(_a == _b * c + _a % _b); // There is no case in which this doesn't hold
    return _a / _b;
  }

  /**
  * @dev Subtracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
  */
  function sub(uint256 _a, uint256 _b) internal pure returns (uint256) {
    assert(_b <= _a);
    return _a - _b;
  }

  /**
  * @dev Adds two numbers, throws on overflow.
  */
  function add(uint256 _a, uint256 _b) internal pure returns (uint256 c) {
    c = _a + _b;
    assert(c >= _a);
    return c;
  }
}

// File: zeppelin-solidity/contracts/token/ERC20/ERC20Basic.sol

/**
 * @title ERC20Basic
 * @dev Simpler version of ERC20 interface
 * See https://github.com/ethereum/EIPs/issues/179
 */
contract ERC20Basic {
  function totalSupply() public view returns (uint256);
  function balanceOf(address _who) public view returns (uint256);
  function transfer(address _to, uint256 _value) public returns (bool);
  event Transfer(address indexed from, address indexed to, uint256 value);
}

// File: zeppelin-solidity/contracts/token/ERC20/BasicToken.sol

/**
 * @title Basic token
 * @dev Basic version of StandardToken, with no allowances.
 */
contract BasicToken is ERC20Basic {
  using SafeMath for uint256;

  mapping(address => uint256) internal balances;

  uint256 internal totalSupply_;

  /**
  * @dev Total number of tokens in existence
  */
  function totalSupply() public view returns (uint256) {
    return totalSupply_;
  }

  /**
  * @dev Transfer token for a specified address
  * @param _to The address to transfer to.
  * @param _value The amount to be transferred.
  */
  function transfer(address _to, uint256 _value) public returns (bool) {
    require(_value <= balances[msg.sender]);
    require(_to != address(0));

    balances[msg.sender] = balances[msg.sender].sub(_value);
    balances[_to] = balances[_to].add(_value);
    emit Transfer(msg.sender, _to, _value);
    return true;
  }

  /**
  * @dev Gets the balance of the specified address.
  * @param _owner The address to query the the balance of.
  * @return An uint256 representing the amount owned by the passed address.
  */
  function balanceOf(address _owner) public view returns (uint256) {
    return balances[_owner];
  }

}

// File: zeppelin-solidity/contracts/token/ERC20/ERC20.sol

/**
 * @title ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
contract ERC20 is ERC20Basic {
  function allowance(address _owner, address _spender)
    public view returns (uint256);

  function transferFrom(address _from, address _to, uint256 _value)
    public returns (bool);

  function approve(address _spender, uint256 _value) public returns (bool);
  event Approval(
    address indexed owner,
    address indexed spender,
    uint256 value
  );
}

// File: zeppelin-solidity/contracts/token/ERC20/StandardToken.sol

/**
 * @title Standard ERC20 token
 *
 * @dev Implementation of the basic standard token.
 * https://github.com/ethereum/EIPs/issues/20
 * Based on code by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
 */
contract StandardToken is ERC20, BasicToken {

  mapping (address => mapping (address => uint256)) internal allowed;


  /**
   * @dev Transfer tokens from one address to another
   * @param _from address The address which you want to send tokens from
   * @param _to address The address which you want to transfer to
   * @param _value uint256 the amount of tokens to be transferred
   */
  function transferFrom(
    address _from,
    address _to,
    uint256 _value
  )
    public
    returns (bool)
  {
    require(_value <= balances[_from]);
    require(_value <= allowed[_from][msg.sender]);
    require(_to != address(0));

    balances[_from] = balances[_from].sub(_value);
    balances[_to] = balances[_to].add(_value);
    allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
    emit Transfer(_from, _to, _value);
    return true;
  }

  /**
   * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
   * 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
   * @param _spender The address which will spend the funds.
   * @param _value The amount of tokens to be spent.
   */
  function approve(address _spender, uint256 _value) public returns (bool) {
    allowed[msg.sender][_spender] = _value;
    emit Approval(msg.sender, _spender, _value);
    return true;
  }

  /**
   * @dev Function to check the amount of tokens that an owner allowed to a spender.
   * @param _owner address The address which owns the funds.
   * @param _spender address The address which will spend the funds.
   * @return A uint256 specifying the amount of tokens still available for the spender.
   */
  function allowance(
    address _owner,
    address _spender
   )
    public
    view
    returns (uint256)
  {
    return allowed[_owner][_spender];
  }

  /**
   * @dev Increase the amount of tokens that an owner allowed to a spender.
   * approve should be called when allowed[_spender] == 0. To increment
   * allowed value is better to use this function to avoid 2 calls (and wait until
   * the first transaction is mined)
   * From MonolithDAO Token.sol
   * @param _spender The address which will spend the funds.
   * @param _addedValue The amount of tokens to increase the allowance by.
   */
  function increaseApproval(
    address _spender,
    uint256 _addedValue
  )
    public
    returns (bool)
  {
    allowed[msg.sender][_spender] = (
      allowed[msg.sender][_spender].add(_addedValue));
    emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
  }

  /**
   * @dev Decrease the amount of tokens that an owner allowed to a spender.
   * approve should be called when allowed[_spender] == 0. To decrement
   * allowed value is better to use this function to avoid 2 calls (and wait until
   * the first transaction is mined)
   * From MonolithDAO Token.sol
   * @param _spender The address which will spend the funds.
   * @param _subtractedValue The amount of tokens to decrease the allowance by.
   */
  function decreaseApproval(
    address _spender,
    uint256 _subtractedValue
  )
    public
    returns (bool)
  {
    uint256 oldValue = allowed[msg.sender][_spender];
    if (_subtractedValue >= oldValue) {
      allowed[msg.sender][_spender] = 0;
    } else {
      allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);
    }
    emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
  }

}

// File: contracts/MidasPooling.sol

contract MidasPooling is Ownable {
    function safeMul(uint a, uint b) internal pure returns (uint) {
        uint c = a * b;
        assert(a == 0 || c / a == b);
        return c;
    }

    function safeSub(uint a, uint b) internal pure returns (uint) {
        assert(b <= a);
        return a - b;
    }

    function safeAdd(uint a, uint b) internal pure returns (uint) {
        uint c = a + b;
        assert(c >= a && c >= b);
        return c;
    }

    string public name = "MidasPooling";
    address public owner;
    address public admin;
    address public feeAccount;
    address public tokenAddress;

    uint256 public withdrawStartTime;
    uint256 public withdrawEndTime;

    mapping(address => uint256) public balances; // mapping of addresses to account balances

    event SetOwner(address indexed previousOwner, address indexed newOwner);
    event SetAdmin(address indexed previousAdmin, address indexed newAdmin);
    event SetFeeAcount(address indexed previousFeeAccount, address indexed newFeeAccount);
    event Deposit(address user, uint256 amount, uint256 balance);
    event Withdraw(address user, uint256 amount, uint256 balance);
    event TransferERC20Token(address token, address owner, uint256 amount);
    event SetBalance(address user, uint256 balance);
    event ChangeWithdrawTimeRange(uint256 withdrawStartTime, uint256 withdrawEndTime);

    modifier onlyAdminOrOwner {
        require(msg.sender == owner);
        require(msg.sender == admin);
        _;
    }

    function setOwner(address newOwner) onlyOwner public {
        owner = newOwner;
        emit SetOwner(owner, newOwner);
    }

    function setAdmin(address newAdmin) onlyOwner public {
        admin = newAdmin;
        emit SetAdmin(admin, newAdmin);
    }

    function setFeeAccount(address newFeeAccount) onlyOwner public {
        feeAccount = newFeeAccount;
        emit SetFeeAcount(feeAccount, newFeeAccount);
    }

    constructor (
        string _name,
        address _admin,
        address _feeAccount,
        address _tokenAddress,
        uint _withdrawStartTime,
        uint _withdrawEndTime) public {
        owner = msg.sender;
        name = _name;
        admin = _admin;
        feeAccount = _feeAccount;
        tokenAddress = _tokenAddress;
        withdrawStartTime = _withdrawStartTime;
        withdrawEndTime = _withdrawEndTime;
    }

    function changeWithdrawTimeRange(uint _withdrawStartTime, uint _withdrawEndTime) onlyAdminOrOwner public {
        require(_withdrawStartTime <= _withdrawEndTime);
        withdrawStartTime = _withdrawStartTime;
        withdrawEndTime = _withdrawEndTime;
        emit ChangeWithdrawTimeRange(_withdrawStartTime, _withdrawEndTime);
    }

    function depositToken(uint256 amount) public returns (bool success) {
        require(amount > 0);
        require(StandardToken(tokenAddress).balanceOf(msg.sender) >= amount);
        require(StandardToken(tokenAddress).transferFrom(msg.sender, this, amount));
        balances[msg.sender] = safeAdd(balances[msg.sender], amount);
        emit Deposit(msg.sender, amount, balances[msg.sender]);
        return true;
    }

    function withdraw(uint256 amount) public returns (bool success) {
        require(amount > 0);
        require(balances[msg.sender] >= amount);
        require(now >= withdrawStartTime);
        require(now <= withdrawEndTime);
        require(StandardToken(tokenAddress).transfer(msg.sender, amount));
        balances[msg.sender] = safeSub(balances[msg.sender], amount);
        emit Withdraw(msg.sender, amount, balances[msg.sender]);
        return true;
    }

    function adminWithdraw(address user, uint256 amount, uint256 feeWithdrawal) onlyAdminOrOwner public returns (bool success) {
        require(balances[user] > amount);
        require(amount > feeWithdrawal);
        uint256 transferAmt = safeSub(amount, feeWithdrawal);
        require(StandardToken(tokenAddress).transfer(user, transferAmt));
        balances[user] = safeSub(balances[user], amount);
        balances[feeAccount] = safeAdd(balances[feeAccount], feeWithdrawal);
        emit Withdraw(user, amount, balances[user]);
        return true;
    }

    function transferERC20Token(address token, uint256 amount) public onlyOwner returns (bool success) {
        emit TransferERC20Token(token, owner, amount);
        return StandardToken(token).transfer(owner, amount);
    }

    function balanceOf(address user) constant public returns (uint256) {
        return balances[user];
    }

    function setBalance(address user, uint256 amount) onlyAdminOrOwner public {
        require(amount >= 0);
        balances[user] = amount;
        emit SetBalance(user, balances[user]);
    }

    function setBalances(address[] users, uint256[] amounts) onlyAdminOrOwner public {
        for (uint i = 0; i < users.length; i++) {
            setBalance(users[i], amounts[i]);
        }
    }
}