pragma solidity ^0.4.11;

contract AvatarNetworkToken {

    // Token name
    string public name = "Avatar_Network_Token";
    
    // Token symbol
    string public constant symbol = "ATT";
    
    // Token decimals
    uint256 public constant decimals = 6;
    
    // INIT SUPPLY
    uint256 public constant INITIAL_SUPPLY = 6000000000 * (10 ** uint256(decimals));

    mapping (address => uint256) public balanceOf;
    mapping (address => mapping (address => uint256)) public allowance;

    // Totle supply of Avatar Network Token
    uint256 public totalSupply = 0;
    
    // Is Running
    bool public stopped = false;

    address owner = 0x0;

    modifier isOwner {
        assert(owner == msg.sender);
        _;
    }

    modifier isRunning {
        assert (!stopped);
        _;
    }

    modifier validAddress {
        assert(0x0 != msg.sender);
        _;
    }

    constructor() public {
        owner = msg.sender;
        totalSupply = INITIAL_SUPPLY;
        balanceOf[msg.sender] = INITIAL_SUPPLY;
        Transfer(0x0, msg.sender, INITIAL_SUPPLY);
    }

    /**
     * @dev Transfer token for a specified address
     * @param _to The address to transfer to.
     * @param _value The amount to be transferred.
     */
    function transfer(address _to, uint256 _value) isRunning validAddress public returns (bool success) {
        // ATT token can't be burned
        require(_to != address(0));
        require(balanceOf[msg.sender] >= _value);
        require(balanceOf[_to] + _value >= balanceOf[_to]);
        balanceOf[msg.sender] -= _value;
        balanceOf[_to] += _value;
        Transfer(msg.sender, _to, _value);
        return true;
    }

    /**
     * @dev Transfer tokens from one address to another
     * @param _from address The address which you want to send tokens from
     * @param _to address The address which you want to transfer to
     * @param _value uint256 the amount of tokens to be transferred
     */
    function transferFrom(address _from, address _to, uint256 _value) isRunning validAddress public returns (bool success) {
        // ATT token can't be burned
        require(_to != address(0));
        require(balanceOf[_from] >= _value);
        require(balanceOf[_to] + _value >= balanceOf[_to]);
        require(allowance[_from][msg.sender] >= _value);
        balanceOf[_to] += _value;
        balanceOf[_from] -= _value;
        allowance[_from][msg.sender] -= _value;
        Transfer(_from, _to, _value);
        return true;
    }

    function approve(address _spender, uint256 _value) isRunning validAddress public returns (bool success) {
        require(_value == 0 || allowance[msg.sender][_spender] == 0);
        allowance[msg.sender][_spender] = _value;
        Approval(msg.sender, _spender, _value);
        return true;
    }
    
    function allowance(address _owner, address _spender) constant public returns (uint256 remaining) {
        return allowance[_owner][_spender];
    }

    function stop() isOwner public {
        stopped = true;
    }

    function start() isOwner public {
        stopped = false;
    }

    function setName(string _name) isOwner public {
        name = _name;
    }

    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);
}