pragma solidity ^0.4.25;

contract FloodToken {

    uint256 constant MAX_UINT256 = 2**256 - 1;
    uint256 public totalSupply;
    string public name;
    uint8 public decimals;
    string public symbol;
    string public version = 'FLOOD0.1';
    uint public init;
    mapping (address => uint256) balances;
    mapping (address => mapping (address => uint256)) allowed;

    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);

    constructor() public {}

    function transfer(address _to, uint256 _value) public returns (bool success) {
        require(balances[msg.sender] >= _value);
        balances[msg.sender] -= _value;
        balances[_to] += _value;
        emit Transfer(msg.sender, _to, _value);
        return true;
    }

    function transferFrom(address _from, address _to, uint256 _value) public  returns (bool success) {
        uint256 allowance = allowed[_from][msg.sender];
        require(balances[_from] >= _value && allowance >= _value);
        balances[_to] += _value;
        balances[_from] -= _value;
        if (allowance < MAX_UINT256) {
            allowed[_from][msg.sender] -= _value;
        }
        emit Transfer(_from, _to, _value);
        return true;
    }

    function balanceOf(address _owner) public constant returns (uint256 balance) {
        return balances[_owner];
    }

    function approve(address _spender, uint256 _value) public returns (bool success) {
        allowed[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;
    }

    function allowance(address _owner, address _spender) public constant returns (uint256 remaining) {
      return allowed[_owner][_spender];
    }

    function burn(uint _amount) public returns (uint256 remaining) {
    	if(balances[msg.sender]>=_amount){
    		if(totalSupply>=_amount){
    			transfer(address(0x0), _amount);
    			balances[address(0x0)]-=_amount;
    			totalSupply-=_amount;
    		}
    	}
        return balances[msg.sender];
    }

    /* Approves and then calls the receiving contract */
    function approveAndCall(address _spender, uint256 _value, bytes _extraData) public returns (bool success) {
        allowed[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        require(_spender.call(bytes4(bytes32(keccak256("receiveApproval(address,uint256,address,bytes)"))), msg.sender, _value, this, _extraData));
        return true;
    }


    function init(
        uint256 _initialAmount,
        string _tokenName,
        uint8 _decimalUnits,
        string _tokenSymbol
        ) public returns (bool){
        if(init>0)revert();
        balances[msg.sender] = _initialAmount;
        totalSupply = _initialAmount;
        name = _tokenName; 
        decimals = _decimalUnits;
        symbol = _tokenSymbol;
        init=1;
        return true;
    }

   
}