pragma solidity ^0.4.21;


/**
 * @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));
    emit OwnershipTransferred(owner, newOwner);
    owner = newOwner;
  }

}



/**
 * @title ERC20Basic
 * @dev Simpler version of ERC20 interface
 * @dev 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);
}







/**
 * @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) {
    if (a == 0) {
      return 0;
    }
    uint256 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 c;
  }

  /**
  * @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) {
    uint256 c = a + b;
    assert(c >= a);
    return c;
  }
}





/**
 * @title Crowdsale
 * @dev Crowdsale is a base contract for managing a token crowdsale,
 * allowing investors to purchase tokens with ether. This contract implements
 * such functionality in its most fundamental form and can be extended to provide additional
 * functionality and/or custom behavior.
 * The external interface represents the basic interface for purchasing tokens, and conform
 * the base architecture for crowdsales. They are *not* intended to be modified / overriden.
 * The internal interface conforms the extensible and modifiable surface of crowdsales. Override 
 * the methods to add functionality. Consider using 'super' where appropiate to concatenate
 * behavior.
 */

contract Crowdsale {
  using SafeMath for uint256;

  // The token being sold
  ERC20 public token;

  // Address where funds are collected
  address public wallet;

  // How many token units a buyer gets per wei
  //uint256 public rate;

  // Amount of wei raised
  uint256 public weiRaised;

  // Amount of wei raised
  uint256 public tokensDistributed;

  /**
   * 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);

  /**
   * @param _wallet Address where collected funds will be forwarded to
   * @param _token Address of the token being sold
   */
  function Crowdsale(address _wallet, ERC20 _token) public {
    require(_wallet != address(0));
    require(_token != address(0));

    wallet = _wallet;
    token = _token;
  }

  // -----------------------------------------
  // Crowdsale external interface
  // -----------------------------------------

  /**
   * @dev fallback function ***DO NOT OVERRIDE***
   */
  function () external payable {
    buyTokens(msg.sender);
  }

  /**
   * @dev low level token purchase ***DO NOT OVERRIDE***
   * @param _beneficiary Address performing the token purchase
   */
  function buyTokens(address _beneficiary) public payable {

    uint256 weiAmount = msg.value;
    _preValidatePurchase(_beneficiary, weiAmount);

    // calculate token amount to be created
    uint256 tokens = _getTokenAmount(weiAmount);

    // update state
    weiRaised = weiRaised.add(weiAmount);
    tokensDistributed = tokensDistributed.add(tokens);

    _processPurchase(_beneficiary, tokens);
    emit TokenPurchase(msg.sender, _beneficiary, weiAmount, tokens);

    _updatePurchasingState(_beneficiary, weiAmount);

    _forwardFunds();
    _postValidatePurchase(_beneficiary, weiAmount);
  }

  // -----------------------------------------
  // Internal interface (extensible)
  // -----------------------------------------

  /**
   * @dev Validation of an incoming purchase. Use require statements to revert state when conditions are not met. Use super to concatenate validations.
   * @param _beneficiary Address performing the token purchase
   * @param _weiAmount Value in wei involved in the purchase
   */
  function _preValidatePurchase(address _beneficiary, uint256 _weiAmount) internal {
    require(_beneficiary != address(0));
    require(_weiAmount != 0);
  }

  /**
   * @dev Validation of an executed purchase. Observe state and use revert statements to undo rollback when valid conditions are not met.
   * @param _beneficiary Address performing the token purchase
   * @param _weiAmount Value in wei involved in the purchase
   */
  function _postValidatePurchase(address _beneficiary, uint256 _weiAmount) internal {
    // optional override
  }

  /**
   * @dev Source of tokens. Override this method to modify the way in which the crowdsale ultimately gets and sends its tokens.
   * @param _beneficiary Address performing the token purchase
   * @param _tokenAmount Number of tokens to be emitted
   */
  function _deliverTokens(address _beneficiary, uint256 _tokenAmount) internal {
    token.transferFrom(wallet, _beneficiary, _tokenAmount);
    //token.transfer(_beneficiary, _tokenAmount);
  }

  /**
   * @dev Executed when a purchase has been validated and is ready to be executed. Not necessarily emits/sends tokens.
   * @param _beneficiary Address receiving the tokens
   * @param _tokenAmount Number of tokens to be purchased
   */
  function _processPurchase(address _beneficiary, uint256 _tokenAmount) internal {
    _deliverTokens(_beneficiary, _tokenAmount);
  }

  /**
   * @dev Override for extensions that require an internal state to check for validity (current user contributions, etc.)
   * @param _beneficiary Address receiving the tokens
   * @param _weiAmount Value in wei involved in the purchase
   */
  function _updatePurchasingState(address _beneficiary, uint256 _weiAmount) internal {
    // optional override
  }

  /**
   * @dev Override to extend the way in which ether is converted to tokens.
   * @param _weiAmount Value in wei to be converted into tokens
   * @return Number of tokens that can be purchased with the specified _weiAmount
   */
  function _getTokenAmount(uint256 _weiAmount) internal view returns (uint256) {
    // must override
  }

  /**
   * @dev Determines how ETH is stored/forwarded on purchases.
   */
  function _forwardFunds() internal {
    wallet.transfer(msg.value);
  }
}


/**
 * @title TimedCrowdsale
 * @dev Crowdsale accepting contributions only within a time frame.
 */
contract TimedCrowdsale is Crowdsale {
  using SafeMath for uint256;

  uint256 public openingTime;
  uint256 public closingTime;

  /**
   * @dev Reverts if not in crowdsale time range. 
   */
  modifier onlyWhileOpen {
    require(now >= openingTime && now <= closingTime);
    _;
  }

  /**
   * @dev Constructor, takes crowdsale opening and closing times.
   * @param _openingTime Crowdsale opening time
   * @param _closingTime Crowdsale closing time
   */
  function TimedCrowdsale(uint256 _openingTime, uint256 _closingTime) public {
    //require(_openingTime >= now);
    require(_closingTime >= _openingTime);

    openingTime = _openingTime;
    closingTime = _closingTime;
  }

  /**
   * @dev Checks whether the period in which the crowdsale is open has already elapsed.
   * @return Whether crowdsale period has elapsed
   */
  function hasClosed() public view returns (bool) {
    return now > closingTime;
  }
  
  /**
   * @dev Extend parent behavior requiring to be within contributing period
   * @param _beneficiary Token purchaser
   * @param _weiAmount Amount of wei contributed
   */
  function _preValidatePurchase(address _beneficiary, uint256 _weiAmount) internal onlyWhileOpen {
    super._preValidatePurchase(_beneficiary, _weiAmount);
  }

}



/**
 * @title FinalizableCrowdsale
 * @dev Extension of Crowdsale where an owner can do extra work
 * after finishing.
 */
contract FinalizableCrowdsale is TimedCrowdsale, Ownable {
  using SafeMath for uint256;

  bool public isFinalized = false;

  event Finalized();

  /**
   * @dev Must be called after crowdsale ends, to do some extra finalization
   * work. Calls the contract's finalization function.
   */
  function finalize() onlyOwner public {
    require(!isFinalized);
    require(hasClosed());

    finalization();
    emit Finalized();

    isFinalized = true;
  }

  /**
   * @dev Can be overridden to add finalization logic. The overriding function
   * should call super.finalization() to ensure the chain of finalization is
   * executed entirely.
   */
  function finalization() internal {
  }
}







/**
 * @title CappedCrowdsale
 * @dev Crowdsale with a limit for total contributions.
 */
contract CappedCrowdsale is Crowdsale {
  using SafeMath for uint256;

  uint256 public cap;

  /**
   * @dev Constructor, takes maximum amount of wei accepted in the crowdsale.
   * @param _cap Max amount of wei to be contributed
   */
  function CappedCrowdsale(uint256 _cap) public {
    require(_cap > 0);
    cap = _cap;
  }

  /**
   * @dev Checks whether the cap has been reached. 
   * @return Whether the cap was reached
   */
  function capReached() public view returns (bool) {
    return weiRaised >= cap;
  }

  /**
   * @dev Extend parent behavior requiring purchase to respect the funding cap.
   * @param _beneficiary Token purchaser
   * @param _weiAmount Amount of wei contributed
   */
  function _preValidatePurchase(address _beneficiary, uint256 _weiAmount) internal {
    super._preValidatePurchase(_beneficiary, _weiAmount);
    require(weiRaised.add(_weiAmount) <= cap);
  }

}












/**
 * @title RefundVault
 * @dev This contract is used for storing funds while a crowdsale
 * is in progress. Supports refunding the money if crowdsale fails,
 * and forwarding it if crowdsale is successful.
 */
contract RefundVault is Ownable {
  using SafeMath for uint256;

  enum State { Active, Refunding, Closed }

  mapping (address => uint256) public deposited;
  address public wallet;
  State public state;

  event Closed();
  event RefundsEnabled();
  event Refunded(address indexed beneficiary, uint256 weiAmount);

  /**
   * @param _wallet Vault address
   */
  function RefundVault(address _wallet) public {
    require(_wallet != address(0));
    wallet = _wallet;
    state = State.Active;
  }

  /**
   * @param investor Investor address
   */
  function deposit(address investor) onlyOwner public payable {
    require(state == State.Active);
    deposited[investor] = deposited[investor].add(msg.value);
  }

  function close() onlyOwner public {
    state = State.Closed;
    emit Closed();
    wallet.transfer(address(this).balance);
  }

  function enableRefunds() onlyOwner public {
    require(state == State.Active);
    state = State.Refunding;
    emit RefundsEnabled();
  }

  /**
   * @param investor Investor address
   */
  function refund(address investor) public {
    require(state == State.Refunding);
    uint256 depositedValue = deposited[investor];
    deposited[investor] = 0;
    investor.transfer(depositedValue);
    emit Refunded(investor, depositedValue);
  }
}



/**
 * @title RefundableCrowdsale
 * @dev Extension of Crowdsale contract that adds a funding goal, and
 * the possibility of users getting a refund if goal is not met.
 * Uses a RefundVault as the crowdsale's vault.
 */
contract RefundableCrowdsale is FinalizableCrowdsale {
  using SafeMath for uint256;

  // minimum amount of funds to be raised in weis
  uint256 public goal;

  // refund vault used to hold funds while crowdsale is running
  RefundVault public vault;
 
  /**
   * @dev Constructor, creates RefundVault. 
   * @param _goal Funding goal
   */
  function RefundableCrowdsale(uint256 _goal) public {
    require(_goal > 0);
    vault = new RefundVault(wallet);
    goal = _goal;
  }

  /**
   * @dev Investors can claim refunds here if crowdsale is unsuccessful
   */
  function claimRefund() public {
    require(isFinalized);
    require(!goalReached());

    vault.refund(msg.sender);
  }

  /**
   * @dev Checks whether funding goal was reached. 
   * @return Whether funding goal was reached
   */
  function goalReached() public view returns (bool) {
    return weiRaised >= goal;
  }

  /**
   * @dev vault finalization task, called when owner calls finalize()
   */
  function finalization() internal {
    if (goalReached()) {
      vault.close();
    } else {
      vault.transferOwnership(owner);
    }

    super.finalization();
  }

  /**
   * @dev Overrides Crowdsale fund forwarding, sending funds to vault.
   */
  function _forwardFunds() internal {
    vault.deposit.value(msg.value)(msg.sender);
  }

}








/**
 * @title PostDeliveryCrowdsale
 * @dev Crowdsale that locks tokens from withdrawal until it ends.
 */
contract PostDeliveryCrowdsale is TimedCrowdsale, Ownable {
  using SafeMath for uint256;

  mapping(address => uint256) public balances;

  /**
   * @dev Overrides parent by storing balances instead of issuing tokens right away.
   * @param _beneficiary Token purchaser
   * @param _tokenAmount Amount of tokens purchased
   */
  function _processPurchase(address _beneficiary, uint256 _tokenAmount) internal {
    balances[_beneficiary] = balances[_beneficiary].add(_tokenAmount);
  }

  /**
   * @dev Withdraw tokens only after crowdsale ends.
   */
  function withdrawTokens(address _beneficiary) public onlyOwner {
    require(hasClosed());
    uint256 amount = balances[_beneficiary];
    require(amount > 0);
    balances[_beneficiary] = 0;
    _deliverTokens(_beneficiary, amount);
  }
}






/**
 * @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);
}


contract CxNcontract is CappedCrowdsale, RefundableCrowdsale, PostDeliveryCrowdsale {
    
    // Only for testNet:
    //uint privSale1start = now;

    // Bounty hive
    address partnerAddress;

    //    //  20 Mar 2018  07:00:00 PM CST
    uint privSale1start = 1521594000;

    //  10 Apr 2018  11:59:00 PM CST
    uint privSale1end = 1523426400;

    // 16 Apr 2018  07:00:00 PM CST
    uint privSale2start = 1523926800;

    // 07 May 2018  11:59:00 PM CST
    uint privSale2end = 1525759200;

    // 11 May 2018 07:00:00 PM CST
    uint saleStart = 1526086800;

    // 18 Jun 2018 11:59:00 PM CST
    uint saleEnd = 1526709600;

    function CxNcontract(uint256 _openingTime, uint256 _closingTime, address _wallet, uint256 _cap, ERC20 _token, uint256 _goal, address _partnerAddress) public payable
        Crowdsale(_wallet, _token)
        CappedCrowdsale(_cap)
        TimedCrowdsale(_openingTime, _closingTime)
        RefundableCrowdsale(_goal) 
    {
        //As goal needs to be met for a successful crowdsale
        //the value needs to less or equal than a cap which is limit for accepted funds
        partnerAddress = _partnerAddress;
        require(_goal <= _cap);
    }

    function _preValidatePurchase(address _beneficiary, uint256 _weiAmount) internal {
        require(checkValue(_weiAmount));
        super._preValidatePurchase(_beneficiary, _weiAmount);
    }

    function _getTokenAmount(uint256 _weiAmount) internal view returns (uint256) {
        return _weiAmount.mul(getRate());
    }

    function checkValue(uint256 amount) internal view returns (bool) {
        if (now > privSale1start && now < privSale1end) 
            return (amount >= 5 ether);
        else if (now > privSale2start && now < privSale2end) 
            return (amount >= 5 ether);
        else if (now > saleStart && now < saleEnd) 
            return (amount >= 0.1 ether);
        return false;
    }

    function getRate() public view returns (uint256) {
        if (now > privSale1start && now < privSale1end) 
            return 14375; // Stage I
        else if (now > privSale2start && now < privSale2end) 
            return 13750; // Stage II
        else if (now > saleStart && now < saleEnd) 
            return 12500; // Public Sale
        return 0;
    }

    function finalization() internal {
        uint256 tokensForPartners = 2800000 ether;
        uint256 tokensNeededToClose = tokensForPartners.add(tokensDistributed);
        
        require(token.balanceOf(wallet) >= tokensNeededToClose);

        token.transferFrom(wallet, partnerAddress, tokensForPartners);

        super.finalization();
    }
}