pragma solidity ^0.4.18;


/**
 * @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 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 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 Basic token
 * @dev Basic version of StandardToken, with no allowances.
 */
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];
  }

}


/**
 * @title Standard ERC20 token
 *
 * @dev Implementation of the basic standard token.
 * @dev https://github.com/ethereum/EIPs/issues/20
 * @dev 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(_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];
  }

  /**
   * @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, 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;
  }

  /**
   * @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, 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 NodeToken is StandardToken {
    string public name = "NodePower";
    string public symbol = "NODE";
    uint8 public decimals = 2;
    bool public mintingFinished = false;
    mapping (address => bool) owners;
    mapping (address => bool) minters;

    event Mint(address indexed to, uint256 amount);
    event MintFinished();
    event OwnerAdded(address indexed newOwner);
    event OwnerRemoved(address indexed removedOwner);
    event MinterAdded(address indexed newMinter);
    event MinterRemoved(address indexed removedMinter);
    event Burn(address indexed burner, uint256 value);

    function NodeToken() public {
        owners[msg.sender] = true;
    }

    /**
     * @dev Function to mint tokens
     * @param _to The address that will receive the minted tokens.
     * @param _amount The amount of tokens to mint.
     * @return A boolean that indicates if the operation was successful.
     */
    function mint(address _to, uint256 _amount) onlyMinter public returns (bool) {
        require(!mintingFinished);
        totalSupply = totalSupply.add(_amount);
        balances[_to] = balances[_to].add(_amount);
        Mint(_to, _amount);
        Transfer(address(0), _to, _amount);
        return true;
    }

    /**
     * @dev Function to stop minting new tokens.
     * @return True if the operation was successful.
     */
    function finishMinting() onlyOwner public returns (bool) {
        require(!mintingFinished);
        mintingFinished = true;
        MintFinished();
        return true;
    }

    /**
     * @dev Burns a specific amount of tokens.
     * @param _value The amount of token to be burned.
     */
    function burn(uint256 _value) public {
        require(_value <= balances[msg.sender]);
        // no need to require value <= totalSupply, since that would imply the
        // sender's balance is greater than the totalSupply, which *should* be an assertion failure

        address burner = msg.sender;
        balances[burner] = balances[burner].sub(_value);
        totalSupply = totalSupply.sub(_value);
        Burn(burner, _value);
    }

    /**
     * @dev Adds administrative role to address
     * @param _address The address that will get administrative privileges
     */
    function addOwner(address _address) onlyOwner public {
        owners[_address] = true;
        OwnerAdded(_address);
    }

    /**
     * @dev Removes administrative role from address
     * @param _address The address to remove administrative privileges from
     */
    function delOwner(address _address) onlyOwner public {
        owners[_address] = false;
        OwnerRemoved(_address);
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owners[msg.sender]);
        _;
    }

    /**
     * @dev Adds minter role to address (able to create new tokens)
     * @param _address The address that will get minter privileges
     */
    function addMinter(address _address) onlyOwner public {
        minters[_address] = true;
        MinterAdded(_address);
    }

    /**
     * @dev Removes minter role from address
     * @param _address The address to remove minter privileges
     */
    function delMinter(address _address) onlyOwner public {
        minters[_address] = false;
        MinterRemoved(_address);
    }

    /**
     * @dev Throws if called by any account other than the minter.
     */
    modifier onlyMinter() {
        require(minters[msg.sender]);
        _;
    }
}


/**
 * @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 NodeCrowdsale {
    using SafeMath for uint256;

    // The token being sold
    NodeToken public token;

    // address where funds are collected
    address public wallet;

    // address where funds are collected
    address public owner;

    // USD cents per ETH exchange rate
    uint256 public rateUSDcETH;

    // PreITO discount is 45%
    uint public constant bonusTokensPercent = 45;

    // PreITO ends on 2018-01-31 23:59:59 UTC
    uint256 public constant endTime = 1517443199;

    // Minimum Deposit in USD cents
    uint256 public constant minContributionUSDc = 1000;


    // 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);
    event RateUpdate(uint256 rate);

    function NodeCrowdsale(address _tokenAddress, uint256 _initialRate) public {
        require(_tokenAddress != address(0));
        token = NodeToken(_tokenAddress);
        rateUSDcETH = _initialRate;
        wallet = msg.sender;
        owner = msg.sender;
    }


    // 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(msg.value != 0);
        require(now <= endTime);

        uint256 weiAmount = msg.value;

        require(calculateUSDcValue(weiAmount) >= minContributionUSDc);

        // calculate token amount to be created
        uint256 tokens = calculateTokenAmount(weiAmount);

        // update state
        weiRaised = weiRaised.add(weiAmount);

        token.mint(beneficiary, tokens);
        TokenPurchase(msg.sender, beneficiary, weiAmount, tokens);

        forwardFunds();
    }

    // set rate
    function setRate(uint256 _rateUSDcETH) public onlyOwner {
        // don't allow to change rate more than 10%
        assert(_rateUSDcETH < rateUSDcETH.mul(110).div(100));
        assert(_rateUSDcETH > rateUSDcETH.mul(90).div(100));
        rateUSDcETH = _rateUSDcETH;
        RateUpdate(rateUSDcETH);
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(msg.sender == owner);
        _;
    }

    // calculate deposit value in USD Cents
    function calculateUSDcValue(uint256 _weiDeposit) public view returns (uint256) {

        // wei per USD cent
        uint256 weiPerUSDc = 1 ether/rateUSDcETH;

        // Deposited value converted to USD cents
        uint256 depositValueInUSDc = _weiDeposit.div(weiPerUSDc);
        return depositValueInUSDc;
    }

    // calculates how much tokens will beneficiary get
    // for given amount of wei
    function calculateTokenAmount(uint256 _weiDeposit) public view returns (uint256) {
        uint256 mainTokens = calculateUSDcValue(_weiDeposit);
        uint256 bonusTokens = mainTokens.mul(bonusTokensPercent).div(100);
        return mainTokens.add(bonusTokens);
    }

    // send ether to the fund collection wallet
    // override to create custom fund forwarding mechanisms
    function forwardFunds() internal {
        wallet.transfer(msg.value);
    }



}