// Vulnerability label: clean
pragma solidity ^0.5.7;

/*
--------------------------------------------------------------------------------
Waste Chain Coin Smart Contract

Credit	: Rejean Leclerc 
Mail 	: rejean.leclerc123@gmail.com

--------------------------------------------------------------------------------
*/

/**
 * @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 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;
  }
}

contract WasteChainCoin {
           
    using SafeMath for uint256;
    
    string public constant name = "Waste Chain Coin";
    string public constant symbol = "WCC";
    uint8 public constant decimals = 18;
    /* The initially/total supply is 10,000,000,000 WCC with 18 decimals */
    uint256 public constant _totalSupply  = 10000000000000000000000000000;
    
    address payable owner;
    mapping(address => uint256) public balances;
    mapping(address => mapping (address => uint256)) public allowed;
    uint256 public RATE = 0;

    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed from, address indexed to, uint256 value);
	
	constructor() public {
	    owner = msg.sender; 
        balances[owner] = _totalSupply;	    
	}
    
   function () external payable {
        convertTokens();
    }
    
    function convertTokens() public payable {
        require(msg.value > 0);
		
        RATE = 18000;
	    uint256 tokens = msg.value.mul(RATE);
    	balances[msg.sender] = balances[msg.sender].add(tokens);
	    balances[owner] = balances[owner].sub(tokens);
    	owner.transfer(msg.value);
    }

    /* Transfer the balance from the sender's address to the address _to */
    function transfer(address _to, uint256 _value) public returns (bool success) {
        if (balances[msg.sender] >= _value
            && _value > 0
            && balances[_to] + _value > balances[_to]) {
              balances[msg.sender] = balances[msg.sender].sub(_value);
              balances[_to] = balances[_to].add(_value);
              emit Transfer(msg.sender, _to, _value);
              return true;
        } else {
            return false;
        }
    }

    /* Withdraws to address _to form the address _from up to the amount _value */
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
        if (balances[_from] >= _value
            && allowed[_from][msg.sender] >= _value
            && _value > 0
            && balances[_to] + _value > balances[_to]) {
              balances[_from] = balances[_from].sub(_value);
              allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
              balances[_to] = balances[_to].add(_value);
              emit Transfer(_from, _to, _value);
              return true;
        } else {
            return false;
        }
    }

    /* Allows _spender to withdraw the _allowance amount form sender */
    function approve(address _spender, uint256 _value) public returns (bool success) {
        if (balances[msg.sender] >= _value) {
            allowed[msg.sender][_spender] = _value;
            emit Approval(msg.sender, _spender, _value);
            return true;
        } else {
            return false;
        }
    }

    /* Checks how much _spender can withdraw from _owner */
    function allowance(address _owner, address _spender) public view returns (uint256 remaining) {
        return allowed[_owner][_spender];
    }

   function balanceOf(address _address) public view returns (uint256 balance) {
        return balances[_address];
    }
    
    function totalSupply() public view returns (uint256 totalSupply) {
        return _totalSupply;
    }
}