pragma solidity 0.4.18;


/**
 * @title ERC20Basic
 * @dev Simpler version of ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/179
 */
contract ERC20Basic {
  uint256 public totalSupply;
  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);
}



/**
 * @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 OwnershipTransferred(address indexed previousOwner, address indexed newOwner);


  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */
  function Ownable() 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 transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function transferOwnership(address newOwner) public onlyOwner {
    require(newOwner != address(0));
    OwnershipTransferred(owner, newOwner);
    owner = newOwner;
  }

}





/**
 * @title SafeMath
 * @dev Math operations with safety checks that throw on error
 */
library SafeMath {
  function mul(uint256 a, uint256 b) internal pure returns (uint256) {
    if (a == 0) {
      return 0;
    }
    uint256 c = a * b;
    assert(c / a == b);
    return c;
  }

  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 c;
  }

  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) {
    uint256 c = a + b;
    assert(c >= a);
    return c;
  }
}







/**
 * @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);
}




/**
 * @title Crowdsale
 * @dev Crowdsale is a base contract for managing a token crowdsale.
 * Crowdsales have a start and end timestamps, where investors can make
 * token purchases and the crowdsale will assign them tokens based
 * on a token per ETH rate. Funds collected are forwarded to a wallet
 * as they arrive.
 */
contract Crowdsale is Ownable {
  using SafeMath for uint256;

  // The token being sold
  ERC20 public token;
  uint256 private transactionNum;

  // start and end timestamps where investments are allowed (both inclusive)
  uint256 public startTime;
  uint256 public endTime;

  // address where funds are collected
  address public wallet;

  // how many token units a buyer gets per wei
  uint256 public rate;
  uint256 public discountRate = 3333;

  // amount of raised money in wei
  uint256 public weiRaised;

  /**
   * event for token purchase logging
   * @param purchaser who paid for the tokens
   * @param beneficiary who got the tokens
   * @param value weis paid for purchase
   * @param amount amount of tokens purchased
   */
  event TokenPurchase(address indexed purchaser, address indexed beneficiary, uint256 value, uint256 amount);


  function Crowdsale(uint256 _startTime, uint256 _endTime, uint256 _rate, address _wallet, address _token) public {
    require(_startTime >= now);
    require(_endTime >= _startTime);
    require(_rate > 0);
    require(_wallet != address(0));

    token = ERC20(_token);
    startTime = _startTime;
    endTime = _endTime;
    rate = _rate;
    wallet = _wallet;
  }

  // fallback function can be used to buy tokens
  function () external payable {
    buyTokens(msg.sender);
  }

  // low level token purchase function
  function buyTokens(address beneficiary) public payable {
    require(beneficiary != address(0));
    require(validPurchase());

    uint256 weiAmount = msg.value;
    uint256 tokens;
    if(transactionNum < 100) {
      tokens = weiAmount.mul(discountRate);
    } else {
      tokens = weiAmount.mul(rate);
    }


    uint256 tokenBalance = token.balanceOf(this);
    require(tokenBalance >= tokens);

    transactionNum = transactionNum + 1;
    // update state
    weiRaised = weiRaised.add(weiAmount);

    token.transfer(beneficiary, tokens);
    TokenPurchase(msg.sender, beneficiary, weiAmount, tokens);

    forwardFunds();
  }

  // @return true if crowdsale event has ended
  function hasEnded() public view returns (bool) {
    return now > endTime;
  }



  // send ether to the fund collection wallet
  // override to create custom fund forwarding mechanisms
  function forwardFunds() internal {
    wallet.transfer(msg.value);
  }

  // @return true if the transaction can buy tokens
  function validPurchase() internal view returns (bool) {
    bool withinPeriod = now >= startTime && now <= endTime;
    bool nonZeroPurchase = msg.value != 0;

    return withinPeriod && nonZeroPurchase;
  }

  function finalization() internal {
    token.transfer(owner, token.balanceOf(this));
  }

}




contract PreICO is Crowdsale {
  using SafeMath for uint256;
  uint256 public cap;
  bool public isFinalized;

  uint256 public minContribution = 100000000000000000;
  uint256 public maxContribution = 1000 ether;
  function PreICO(uint256 _startTime, uint256 _endTime, uint256 _rate, uint256 _cap, address _wallet, address _token) public
  Crowdsale(_startTime, _endTime, _rate, _wallet, _token)
  {
      cap = _cap;
  }

  function hasEnded() public view returns (bool) {
    bool capReached = weiRaised >= cap;
    return capReached || super.hasEnded();
  }

  // overriding Crowdsale#validPurchase to add extra cap logic
  // @return true if investors can buy at the moment
  function validPurchase() internal view returns (bool) {
    //0.1 eth and 1000 eth
    bool withinRange = msg.value >= minContribution && msg.value <= maxContribution;
    bool withinCap = weiRaised.add(msg.value) <= cap;
    return withinRange && withinCap && super.validPurchase();
  }

  function changeMinContribution(uint256 _minContribution) public onlyOwner {
    require(_minContribution > 0);
    minContribution = _minContribution;
  }

  function changeMaxContribution(uint256 _maxContribution) public onlyOwner {
    require(_maxContribution > 0);
    maxContribution = _maxContribution;
  }

  function finalize() onlyOwner public {
    require(!isFinalized);
    require(hasEnded());
    super.finalization();
    isFinalized = true;
  }

  function setNewWallet(address _newWallet) onlyOwner public {
    wallet = _newWallet;
  }

}