pragma solidity ^0.4.24;

/**
Double%

Earn 10% per hour, double your %ROI every hour you HODL!

First hour: 10%
Second hour: 20%
Third hour: 40%
...etc...

*/
contract DoubleROI {

    using SafeMath for uint256;

    mapping(address => uint256) investments;
    mapping(address => uint256) joined;
    mapping(address => uint256) referrer;

    uint256 public step = 2400;
    uint256 public minimum = 10 finney;
    uint256 public maximum = 5 ether;
    uint256 public stakingRequirement = 0.5 ether;
    address public ownerWallet;
    address public owner;

    event Invest(address investor, uint256 amount);
    event Withdraw(address investor, uint256 amount);
    event Bounty(address hunter, uint256 amount);
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Сonstructor Sets the original roles of the contract
     */

    constructor() public {
        owner = msg.sender;
        ownerWallet = msg.sender;
    }

    /**
     * @dev Modifiers
     */

    modifier onlyOwner() {
        require(msg.sender == owner);
        _;
    }

    /**
     * @dev Allows current owner to transfer control of the contract to a newOwner.
     * @param newOwner The address to transfer ownership to.
     * @param newOwnerWallet The address to transfer ownership to.
     */
    function transferOwnership(address newOwner, address newOwnerWallet) public onlyOwner {
        require(newOwner != address(0));
        emit OwnershipTransferred(owner, newOwner);
        owner = newOwner;
        ownerWallet = newOwnerWallet;
    }

    /**
     * @dev Investments
     */
    function () public payable {
        buy(0x0);
    }

    function buy(address _referredBy) public payable {
        require(msg.value >= minimum);
        require(msg.value <= maximum);

        address _customerAddress = msg.sender;

        if(
           // is this a referred purchase?
           _referredBy != 0x0000000000000000000000000000000000000000 &&

           // no cheating!
           _referredBy != _customerAddress &&

           // does the referrer have at least X whole tokens?
           // i.e is the referrer a godly chad masternode
           investments[_referredBy] >= stakingRequirement
       ){
           // wealth redistribution
           referrer[_referredBy] = referrer[_referredBy].add(msg.value.mul(5).div(100));
       }

       if (investments[msg.sender] > 0){
           withdraw();
       }
       
       investments[msg.sender] = investments[msg.sender].add(msg.value);
       joined[msg.sender] = block.timestamp;
       ownerWallet.transfer(msg.value.mul(5).div(100));
       emit Invest(msg.sender, msg.value);
    }

    /**
    * @dev Evaluate current balance
    * @param _address Address of investor
    */
    function getBalance(address _address) view public returns (uint256) {
        uint256 minutesCount = now.sub(joined[_address]).div(1 minutes);
        
        // update roi multiplier
        // 10% flat during first hour
        // 20% flat during second hour
        // 40% flat during third hour
        uint256 userROIMultiplier = 2**(minutesCount / 60);
        
        uint256 percent;
        uint256 balance;
        
        for(uint i=1; i<userROIMultiplier; i=i*2){
            // add each percent -
            // first hour is 10%
            // second hour is 20%
            // third hour is 40%
            // etc - add all these up
            percent = investments[_address].mul(step).div(1000) * i;
            balance += percent.mul(60).div(1440);
            
        }
        
        // Finally, add the balance for the current multiplier
        percent = investments[_address].mul(step).div(1000) * userROIMultiplier;
        balance += percent.mul(minutesCount % 60).div(1440);

        return balance;
    }

    /**
    * @dev Withdraw dividends from contract
    */
    function withdraw() public returns (bool){
        require(joined[msg.sender] > 0);
        
        uint256 balance = getBalance(msg.sender);
        
        // Reset ROI mulitplier of user
        joined[msg.sender] = block.timestamp;
        
        if (address(this).balance > balance){
            if (balance > 0){
                msg.sender.transfer(balance);
                emit Withdraw(msg.sender, balance);
            }
            return true;
        } else {
            if (balance > 0) {
                msg.sender.transfer(address(this).balance);
                emit Withdraw(msg.sender, balance);
            }
            return true;
        }
    }

    /**
    * @dev Bounty reward
    */
    function bounty() public {
        uint256 refBalance = checkReferral(msg.sender);
        if(refBalance >= minimum) {
             if (address(this).balance > refBalance) {
                referrer[msg.sender] = 0;
                msg.sender.transfer(refBalance);
                emit Bounty(msg.sender, refBalance);
             }
        }
    }

    /**
    * @dev Gets balance of the sender address.
    * @return An uint256 representing the amount owned by the msg.sender.
    */
    function checkBalance() public view returns (uint256) {
        return getBalance(msg.sender);
    }


    /**
    * @dev Gets investments of the specified address.
    * @param _investor The address to query the the balance of.
    * @return An uint256 representing the amount owned by the passed address.
    */
    function checkInvestments(address _investor) public view returns (uint256) {
        return investments[_investor];
    }

    /**
    * @dev Gets referrer balance of the specified address.
    * @param _hunter The address of the referrer
    * @return An uint256 representing the referral earnings.
    */
    function checkReferral(address _hunter) public view returns (uint256) {
        return referrer[_hunter];
    }
}

/**
 * @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;
    }
}