pragma solidity ^0.4.23;

library SafeMath {
  function mul(uint256 a, uint256 b) internal pure returns (uint256 c) {
    if (a == 0) {
      return 0;
    }
    c = a * b;
    assert(c / a == b);
    return c;
  }

  function div(uint256 a, uint256 b) internal pure returns (uint256) {
    return a / b;
  }

  function sub(uint256 a, uint256 b) internal pure returns (uint256) {
    assert(b <= a);
    return a - b;
  }

  function add(uint256 a, uint256 b) internal pure returns (uint256 c) {
    c = a + b;
    assert(c >= a);
    return c;
  }
}

contract Ownable {
  address public owner;

  event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

  modifier onlyOwner() {
    require(msg.sender == owner);
    _;
  }

  function transferOwnership(address newOwner) public onlyOwner {
    require(newOwner != address(0));
    emit OwnershipTransferred(owner, newOwner);
    owner = newOwner;
  }
}

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);
}

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);
}

contract BasicToken is ERC20Basic {
  using SafeMath for uint256;

  mapping(address => uint256) balances;

  uint256 totalSupply_;

  function totalSupply() public view returns (uint256) {
    return totalSupply_;
  }

  function transfer(address _to, uint256 _value) public returns (bool) {
    require(_to != address(0));
    require(_value <= balances[msg.sender]);

    balances[msg.sender] = balances[msg.sender].sub(_value);
    balances[_to] = balances[_to].add(_value);
    emit Transfer(msg.sender, _to, _value);
    return true;
  }

  function balanceOf(address _owner) public view returns (uint256) {
    return balances[_owner];
  }
}

contract StandardToken is ERC20, BasicToken {

  mapping (address => mapping (address => uint256)) internal allowed;

  function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
    require(_to != address(0));
    require(_value <= balances[_from]);
    require(_value <= allowed[_from][msg.sender]);

    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;
  }

  function approve(address _spender, uint256 _value) public returns (bool) {
    allowed[msg.sender][_spender] = _value;
    emit Approval(msg.sender, _spender, _value);
    return true;
  }

  function allowance(address _owner, address _spender) public view returns (uint256) {
    return allowed[_owner][_spender];
  }

  function increaseApproval(address _spender, uint _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;
  }

  function decreaseApproval(address _spender, uint _subtractedValue) public returns (bool) {
    uint 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;
  }
}

contract MintableToken is StandardToken, Ownable {
  event Mint(address indexed to, uint256 amount);

  modifier hasMintPermission() {
    require(msg.sender == owner);
    _;
  }

  function mint(address _to, uint256 _amount) hasMintPermission public returns (bool) {
    totalSupply_ = totalSupply_.add(_amount);
    balances[_to] = balances[_to].add(_amount);
    emit Mint(_to, _amount);
    emit Transfer(address(0), _to, _amount);
    return true;
  }
}


contract Crowdsale {
  using SafeMath for uint256;

  ERC20 public token;
  address public wallet;
  uint256 public rate;
  uint256 public weiRaised;

  event TokenPurchase(address indexed purchaser, address indexed beneficiary, uint256 value, uint256 amount);

  constructor(uint256 _rate, address _wallet, ERC20 _token) public {
    require(_rate > 0);
    require(_wallet != address(0));
    require(_token != address(0));

    rate = _rate;
    wallet = _wallet;
    token = _token;
  }

  function () external payable {
    buyTokens(msg.sender);
  }

  function buyTokens(address _beneficiary) public payable {

    uint256 weiAmount = msg.value;
    _preValidatePurchase(_beneficiary, weiAmount);

    uint256 tokens = _getTokenAmount(weiAmount);

    weiRaised = weiRaised.add(weiAmount);

    _deliverTokens(_beneficiary, tokens);

    emit TokenPurchase(
      msg.sender,
      _beneficiary,
      weiAmount,
      tokens
    );

    _forwardFunds();
  }

  function _preValidatePurchase(address _beneficiary, uint256 _weiAmount) internal pure {
    require(_beneficiary != address(0));
    require(_weiAmount != 0);
  }

  function _deliverTokens(address _beneficiary, uint256 _tokenAmount) internal {
    token.transfer(_beneficiary, _tokenAmount);
  }

  function _getTokenAmount(uint256 _weiAmount) internal view returns (uint256) {
    return _weiAmount.mul(rate);
  }

  function _forwardFunds() internal {
    wallet.transfer(msg.value);
  }

  function _newWallet(address _newAddress) public {
      require(msg.sender == wallet);
      wallet = _newAddress;
  }
}

contract MintedCrowdsale is Crowdsale {
  function _deliverTokens(address _beneficiary, uint256 _tokenAmount) internal {
    require(MintableToken(token).mint(_beneficiary, _tokenAmount));
  }
}

contract CrowdsaleConstructor is MintedCrowdsale {
  constructor(uint256 _rate, address _wallet, MintableToken _token) public Crowdsale(_rate, _wallet, _token){}
}