pragma solidity ^0.5.0;

library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     * - Multiplication cannot 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-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

contract clashPay {
    using SafeMath for uint256;
    string  public name = "Clash Pay";
    string  public symbol = "SCP";
    uint8   public decimals = 18;
    uint256 public totalSupply = 10*(10**18);
    uint256 public MaxSupply = 10*(10**(29));
    address public owner;
    address public Tokenfarm;

    event Transfer(
        address indexed _from,
        address indexed _to,
        uint256 _value
    );

    event Burn(
        address indexed burner,
        uint256 value
    );

    event Approval(
        address indexed _owner,
        address indexed _spender,
        uint256 _value
    );

    mapping(address => uint256) public balanceOf;
    mapping(address => mapping(address => uint256)) public allowance;

    constructor() public {
        balanceOf[msg.sender] = totalSupply;
        owner= msg.sender;
    }
    function setContract(address _contract) external{
        require(msg.sender==owner,"must be owner");
        Tokenfarm=_contract;
    }

    function transfer(address _to, uint256 _value) external returns (bool success) {
        require(address(0)!= _to,"to burn tokens use the burn function");
        balanceOf[msg.sender] =balanceOf[msg.sender].sub( _value);
        balanceOf[_to] = balanceOf[_to].add( _value);
        emit Transfer(msg.sender, _to, _value);
        return true;
    }

    function approve(address _spender, uint256 _value) external returns (bool success) {
        allowance[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;
    }

    function transferFrom(address _from, address _to, uint256 _value) external returns (bool success) {
        require(address(0)!= _to,"to burn tokens use the burn function");
        balanceOf[_from] = balanceOf[_from].sub( _value);
        balanceOf[_to] = balanceOf[_to].add( _value);
        allowance[_from][msg.sender] =allowance[_from][msg.sender].sub(_value);
        emit Transfer(_from, _to, _value);
        return true;
    }
    function mint(address _to,uint256 _value) public {
        require(msg.sender==Tokenfarm,"only Tokenfarm contract can mint tokens");
        if(totalSupply.add(_value)>=MaxSupply){
            _value = MaxSupply.sub(totalSupply);
        }
        totalSupply= totalSupply.add( _value);
        balanceOf[_to]=balanceOf[_to].add(_value);
        emit Transfer(address(0),_to,_value);
    }
    function burn(uint256 _value) public{
        balanceOf[msg.sender] =balanceOf[msg.sender].sub( _value);
        totalSupply = totalSupply.sub(_value);
        emit Burn(msg.sender,_value);
        emit Transfer(msg.sender,address(0),_value);
    }
    function transferOwnership(address _newOwner) external{
        require(msg.sender==owner,"only the owner an call this function");
        owner=_newOwner;

    }

}