pragma solidity ^0.4.18;

/*
Nodepower ICO crowdsale contract
BONUS SCHEDULE:
        Bonus        start time               end time
        45%     2017-12-31 23:59:59 - 2018-01-31 23:59:59 1517443199
        40%     2018-02-01 00:00:00 - 2018-02-14 23:59:59 1518652799
        30%     2018-02-15 00:00:00 - 2018-02-24 23:59:59 1519516799
        20%     2018-02-25 00:00:00 - 2018-03-06 23:59:59 1520380799
        15%     2018-03-07 00:00:00 - 2018-03-16 23:59:59 1521244799
        10%     2018-03-17 00:00:00 - 2018-03-26 23:59:59 1522108799

See official resource for details https://nodepower.io/
*/

/**
 * @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 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 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 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 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 NodeCrowdsale
 * @dev NodeCrowdsale is a contract for managing a token crowdsale for NodePower project.
 * Crowdsale have 6 phases with start and end timestamps, where investors can make
 * token purchases and the crowdsale will assign them tokens based
 * on a token per ETH rate and bonuses. Collected funds are forwarded to a wallet
 * as they arrive.
 */
contract NodeCrowdsale {
    using SafeMath for uint256;

    // The token being sold
    NodeToken public token;

    // External wallet where funds get forwarded
    address public wallet;

    // Crowdsale administrators
    mapping (address => bool) public owners;

    // External bots updating rates
    mapping (address => bool) public bots;

    // USD cents per ETH exchange rate
    uint256 public rateUSDcETH;

    // Phases list, see schedule in constructor
    mapping (uint => Phase) phases;

    // The total number of phases (0...5)
    uint public totalPhases = 6;

    // Description for each phase
    struct Phase {
        uint256 startTime;
        uint256 endTime;
        uint256 bonusPercent;
    }

    // Minimum Deposit in USD cents
    uint256 public constant minContributionUSDc = 1000;


    // Amount of raised Ethers (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 bonusPercent free tokens percantage for the phase
     * @param amount amount of tokens purchased
     */
    event TokenPurchase(address indexed purchaser, address indexed beneficiary, uint256 value, uint256 bonusPercent, uint256 amount);

    // event for rate update logging
    event RateUpdate(uint256 rate);

    // event for wallet update
    event WalletSet(address indexed wallet);

    // owners management events
    event OwnerAdded(address indexed newOwner);
    event OwnerRemoved(address indexed removedOwner);

    // bot management events
    event BotAdded(address indexed newBot);
    event BotRemoved(address indexed removedBot);

    function NodeCrowdsale(address _tokenAddress, uint256 _initialRate) public {
        require(_tokenAddress != address(0));
        token = NodeToken(_tokenAddress);
        rateUSDcETH = _initialRate;
        wallet = msg.sender;
        owners[msg.sender] = true;
        bots[msg.sender] = true;
        /*
        ICO SCHEDULE
        Bonus        start time               end time
        45%     2017-12-31 23:59:59 1514764799 2018-01-31 23:59:59 1517443199
        40%     2018-02-01 00:00:00 1517443200 2018-02-14 23:59:59 1518652799
        30%     2018-02-15 00:00:00 1518652800 2018-02-24 23:59:59 1519516799
        20%     2018-02-25 00:00:00 1519516800 2018-03-06 23:59:59 1520380799
        15%     2018-03-07 00:00:00 1520380800 2018-03-16 23:59:59 1521244799
        10%     2018-03-17 00:00:00 1521244800 2018-03-26 23:59:59 1522108799
        00%     2018-03-27 00:00:00 1522108800 -
        */
        phases[0].bonusPercent = 45;
        phases[0].startTime = 1514764799;
        phases[0].endTime = 1517443199;
        phases[1].bonusPercent = 40;
        phases[1].startTime = 1517443200;
        phases[1].endTime = 1518652799;
        phases[2].bonusPercent = 30;
        phases[2].startTime = 1518652800;
        phases[2].endTime = 1519516799;
        phases[3].bonusPercent = 20;
        phases[3].startTime = 1519516800;
        phases[3].endTime = 1520380799;
        phases[4].bonusPercent = 15;
        phases[4].startTime = 1520380800;
        phases[4].endTime = 1521244799;
        phases[5].bonusPercent = 10;
        phases[5].startTime = 1521244800;
        phases[5].endTime = 1522108799;
    }

    /**
     * @dev Update collecting wallet address
     * @param _address The address to send collected funds
     */
    function setWallet(address _address) onlyOwner public {
        wallet = _address;
        WalletSet(_address);
    }


    // 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);

        uint256 currentBonusPercent = getBonusPercent(now);

        uint256 weiAmount = msg.value;

        require(calculateUSDcValue(weiAmount) >= minContributionUSDc);

        // calculate token amount to be created
        uint256 tokens = calculateTokenAmount(weiAmount, currentBonusPercent);

        // update state
        weiRaised = weiRaised.add(weiAmount);

        token.mint(beneficiary, tokens);
        TokenPurchase(msg.sender, beneficiary, weiAmount, currentBonusPercent, tokens);

        forwardFunds();
    }

    // If phase exists return corresponding bonus for the given date
    // else return 0 (percent)
    function getBonusPercent(uint256 datetime) public view returns (uint256) {
        for (uint i = 0; i < totalPhases; i++) {
            if (datetime >= phases[i].startTime && datetime <= phases[i].endTime) {
                return phases[i].bonusPercent;
            }
        }
        return 0;
    }

    // set rate
    function setRate(uint256 _rateUSDcETH) public onlyBot {
        // 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 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 rate updating bot
     * @param _address The address of the rate bot
     */
    function addBot(address _address) onlyOwner public {
        bots[_address] = true;
        BotAdded(_address);
    }

    /**
     * @dev Removes rate updating bot address
     * @param _address The address of the rate bot
     */
    function delBot(address _address) onlyOwner public {
        bots[_address] = false;
        BotRemoved(_address);
    }

    /**
     * @dev Throws if called by any account other than the bot.
     */
    modifier onlyBot() {
        require(bots[msg.sender]);
        _;
    }

    // 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, uint256 _bonusTokensPercent) 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);
    }



}