pragma solidity ^0.4.24;

/**
 * @title SafeMath
 * @dev Math operations with safety checks that revert on error
 */
library SafeMath {

  /**
  * @dev Multiplies two numbers, reverts on overflow.
  */
  function mul(uint256 _a, uint256 _b) internal pure returns (uint256) {
    // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
    // benefit is lost if 'b' is also tested.
    // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
    if (_a == 0) {
      return 0;
    }

    uint256 c = _a * _b;
    require(c / _a == _b);

    return c;
  }

  /**
  * @dev Integer division of two numbers truncating the quotient, reverts on division by zero.
  */
  function div(uint256 _a, uint256 _b) internal pure returns (uint256) {
    require(_b > 0); // Solidity only automatically asserts 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, reverts on overflow (i.e. if subtrahend is greater than minuend).
  */
  function sub(uint256 _a, uint256 _b) internal pure returns (uint256) {
    require(_b <= _a);
    uint256 c = _a - _b;

    return c;
  }

  /**
  * @dev Adds two numbers, reverts on overflow.
  */
  function add(uint256 _a, uint256 _b) internal pure returns (uint256) {
    uint256 c = _a + _b;
    require(c >= _a);

    return c;
  }

  /**
  * @dev Divides two numbers and returns the remainder (unsigned integer modulo),
  * reverts when dividing by zero.
  */
  function mod(uint256 a, uint256 b) internal pure returns (uint256) {
    require(b != 0);
    return a % b;
  }
}

/**
 * @title ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
interface IERC20 {
  function totalSupply() external view returns (uint256);

  function balanceOf(address _who) external view returns (uint256);

  function allowance(address _owner, address _spender)
    external view returns (uint256);

  function transfer(address _to, uint256 _value) external returns (bool);

  function approve(address _spender, uint256 _value)
    external returns (bool);

  function transferFrom(address _from, address _to, uint256 _value)
    external returns (bool);

  event Transfer(
    address indexed from,
    address indexed to,
    uint256 value
  );

  event Approval(
    address indexed owner,
    address indexed spender,
    uint256 value
  );
}

contract StandardToken is IERC20 {
    using SafeMath for uint256;

    mapping(address => uint256) balances;

    mapping (address => mapping (address => uint256)) internal allowed;

    uint256 totalSupply_;

    /**
    * @dev Total number of tokens in existence
    */
    function totalSupply() public view returns (uint256) {
        return totalSupply_;
    }

    function balanceOf(address _owner) public view returns (uint256) {
        return balances[_owner];
    }

    function allowance(
        address _owner,
        address _spender
    )
        public
        view
        returns (uint256)
    {
        return allowed[_owner][_spender];
    }

    function transfer(address _to, uint256 _value) public returns (bool) {
        require(_value <= balances[msg.sender]);
        require(_to != address(0));

        balances[msg.sender] = balances[msg.sender].sub(_value);
        balances[_to] = balances[_to].add(_value);
        emit Transfer(msg.sender, _to, _value);
        return true;
    }

    function approve(address _spender, uint256 _value) public returns (bool) {
        allowed[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;
    }

    function transferFrom(
        address _from,
        address _to,
        uint256 _value
    )
        public
        returns (bool)
    {
        require(_value <= balances[_from]);
        require(_value <= allowed[_from][msg.sender]);
        require(_to != address(0));

        balances[_from] = balances[_from].sub(_value);
        balances[_to] = balances[_to].add(_value);
        allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
        emit Transfer(_from, _to, _value);
        return true;
    }
}

/**
 * @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.
    */
    constructor() 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 {
        _transferOwnership(_newOwner);
    }

    /**
    * @dev Transfers control of the contract to a newOwner.
    * @param _newOwner The address to transfer ownership to.
    */
    function _transferOwnership(address _newOwner) internal {
        require(_newOwner != address(0));
        emit OwnershipTransferred(owner, _newOwner);
        owner = _newOwner;
    }
}
contract OleCoin is StandardToken, Ownable {

    event tokenComprado(address comprador);
    
    
    string public constant name = "OleCoin";
    string public constant symbol = "OLE";
    uint8 public constant decimals = 18;
    
    uint256 public constant INITIAL_SUPPLY = 150000000 * (10 ** uint256(decimals));
    
    event tokenBought(address adr);
    
    uint256 tokenPrice;    

    constructor() public payable{
        totalSupply_ = INITIAL_SUPPLY;
        balances[msg.sender] = INITIAL_SUPPLY;
        emit Transfer(address(0), msg.sender, INITIAL_SUPPLY);
        tokenPrice = 100000000000000 wei;
    }
    
    function() public payable {
        emit tokenComprado(msg.sender);
    }

    function getBalance() public view returns(uint256) {
        return address(this).balance;
    }

    function setPrice(uint256 _priceToken) public onlyOwner {
        tokenPrice = _priceToken;
    }
    function saque() public onlyOwner {
        address(owner).transfer(getBalance());
    }
        
    function comprarTokens(uint256 qtd) public payable {
        require(qtd > 0);
        //require(msg.value > 0);
        require(msg.value == (qtd * tokenPrice));
        qtd = qtd * (10 ** uint256(decimals));
        balances[owner] = balances[owner].sub(qtd);
        balances[msg.sender] = balances[msg.sender].add(qtd);
        address(this).transfer(msg.value);
        emit Transfer(owner, msg.sender, qtd);
    }
    
}