pragma solidity ^0.4.18;



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);
}


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;
  }
}


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;
  }

}


contract BasicToken is ERC20Basic {
  using SafeMath for uint256;

  mapping(address => uint256) balances;
  

  /**
  * @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(_to != address(0));
    require(_value <= balances[msg.sender]);

    // SafeMath.sub will throw if there is not enough balance.
    balances[msg.sender] = balances[msg.sender].sub(_value);
    balances[_to] = balances[_to].add(_value);
    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 balance) {
    return balances[_owner];
  }

}


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 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(_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);
    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;
    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];
  }

  /**
   * 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
   */
  function increaseApproval(address _spender, uint _addedValue) public returns (bool) {
    allowed[msg.sender][_spender] = allowed[msg.sender][_spender].add(_addedValue);
    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);
    }
    Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
  }

}

contract TOKKA is StandardToken {
    string public name = "StreamPay Token";
    string public symbol = "STPY";
    uint256 public decimals = 18;

   
    function TOKKA() public {
       totalSupply = 35000000 * 10**18;
       balances[msg.sender] = totalSupply;
    }
}


contract Crowdsale is Ownable {
  using SafeMath for uint256;

   // The token being sold
  TOKKA public token;

  // 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 (500)
  uint256 public rate ;

  // amount of raised money in wei
  uint256 public weiRaised;
  
  // Our Goal is 68254.06111663644 Ethers Hardcap
  uint256 public CAP = 68254061116636440000000;
  
  bool crowdsaleClosed = false;
  
  //Bonus Parameters
  
  uint256 public PreIcobonusEnds = 1535731200;
  
  uint256 public StgOnebonusEnds = 1538323200;
  uint256 public StgTwobonusEnds = 1541001600;
  uint256 public StgThreebonusEnds = 1543593600;
  uint256 public StgFourbonusEnds = 1546272000;
  
  
  

  event TokenPurchase(address indexed purchaser, address indexed beneficiary, uint256 value, uint256 amount);


  function Crowdsale(uint256 _startTime, uint256 _endTime, uint256 _rate, address _wallet) public {
    require(_startTime >= now);
    require(_endTime >= _startTime);
    require(_rate > 0);
    require(_wallet != address(0));

    startTime = _startTime;
    endTime = _endTime;
    rate = _rate;
    wallet = _wallet;
    
    //Bonus Parametersss
    
    //StgOnebonusEnds = _bonusEnds;
    
    token = createTokenContract();
  }

// creates the token to be sold.
// override this method to have crowdsale of a specific mintable token.
function createTokenContract() internal returns (TOKKA) {
    return new TOKKA();
  }


  // 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());
    require(!crowdsaleClosed);
    
    //Bounus Conditions
    
    
    
    if (now <= PreIcobonusEnds) {
            rate = 667;
         } 
    
     else if (now <= StgOnebonusEnds && now > PreIcobonusEnds) {
            rate = 641;
         }  
    
    else if (now <= StgTwobonusEnds && now > StgOnebonusEnds ) {
            rate = 616;
         }  
     
     else if (now <= StgThreebonusEnds && now > StgTwobonusEnds ) {
            rate = 590;
         } 
         else if (now <= StgFourbonusEnds && now > StgThreebonusEnds ) {
            rate = 564;
         }
    else{
        rate = 513;
    }
     
    

    uint256 weiAmount = msg.value;

    // calculate token amount to be created
    uint256 tokens = weiAmount.mul(rate);

    // update state
    weiRaised = weiRaised.add(weiAmount);

    // transfer tokens purchased 
    //ERC20(token).transfer(this, tokens);
    //StandardToken(token).transfer(this, tokens);
    token.transfer(beneficiary, tokens);

    TokenPurchase(msg.sender, beneficiary, weiAmount, tokens);

    forwardFunds();
}


  function forwardFunds() internal {
    wallet.transfer(msg.value);
  }


  function validPurchase() internal view returns (bool) {
    bool withinPeriod = now >= startTime && now <= endTime;
    bool nonZeroPurchase = msg.value != 0;
    return withinPeriod && nonZeroPurchase;
  }


  function hasEnded() public view returns (bool) {
    return now > endTime;
  }
  
  function GoalReached() public view returns (bool) {
    return (weiRaised >= CAP);
  }
  
  function Pause() public onlyOwner
  {
       //if (weiRaised >= CAP){
           
        //}
        require(weiRaised >= CAP);
        
        crowdsaleClosed = true;
  }
  
  function Play() public onlyOwner
  {
       //if (weiRaised >= CAP){
           
        //}
        require(crowdsaleClosed == true);
        
        crowdsaleClosed = false;
  }

}