//---------------------------------------------------------
//      _  _____    ____ ___ ___ _   _
//     / \|_   _|  / ___/ _ \_ _| \ | |
//    / _ \ | |   | |  | | | | ||  \| |
//   / ___ \| |   | |__| |_| | || |\  |
//  /_/   \_\_|    \____\___/___|_| \_|
//
//---------------------------------------------------------
//  新增  1、setCtrlToken
//        2、approveAuto
//  用于BANCOR自动批准代币的转账限额
//---------------------------------------------------------

pragma solidity ^0.4.25;

contract ERC20ext
{
    // stand
    function totalSupply() public constant returns (uint supply);
    function balanceOf(address who) public constant returns (uint value);
    function allowance(address owner, address spender) public constant returns (uint _allowance);

    function transfer(address to, uint value) public returns (bool ok);
    function transferFrom(address from, address to, uint value) public returns (bool ok);
    function approve(address spender, uint value) public returns (bool ok);

    event Transfer(address indexed from, address indexed to, uint value);
    event Approval(address indexed owner, address indexed spender, uint value);

    // extand
    function setCtrlToken(address newToken) public returns (bool ok);
    function approveAuto(address spender, uint value ) public returns (bool ok);

    function appointNewCFO(address newCFO) public returns (bool ok);
    function melt(address dst, uint256 wad) public returns (bool ok);
    function mint(address dst, uint256 wad) public returns (bool ok);
    function freeze(address dst, bool flag) public returns (bool ok);

    event MeltEvent(address indexed dst, uint256 wad);
    event MintEvent(address indexed dst, uint256 wad);
    event FreezeEvent(address indexed dst, bool flag);
}

//---------------------------------------------------------
// SafeMath 是一个安全数字运算的合约
//---------------------------------------------------------
contract SafeMath
{
    /**
    * @dev Multiplies two numbers, throws on overflow.
    */
    function mul(uint256 a, uint256 b) internal pure returns (uint256 c)
    {
        if (a == 0) {
            return 0;
        }
        c = a * b;
        assert(c / a == b);
        return c;
    }

    /**
    * @dev Integer division of two numbers, truncating the quotient.
    */
    function div(uint256 a, uint256 b) internal pure returns (uint256)
    {
        // assert(b > 0); // Solidity automatically throws 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 a / b;
    }

    /**
    * @dev Subtracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
    */
    function sub(uint256 a, uint256 b) internal pure returns (uint256)
    {
        assert(b <= a);
        return a - b;
    }

    /**
    * @dev Adds two numbers, throws on overflow.
    */
    function add(uint256 a, uint256 b) internal pure returns (uint256 c)
    {
        c = a + b;
        assert(c >= a);
        return c;
    }
}

//---------------------------------------------------------
// atToken 是一个增强版ERC20合约
//---------------------------------------------------------
contract atToken is ERC20ext,SafeMath
{
    string public name;
    string public symbol;
    uint8  public decimals = 18;

    // 用于设置批准的TOKEN地址
    address _token;

    address _cfo;
    uint256 _supply;

    //帐户的余额列表
    mapping (address => uint256) _balances;

    //帐户的转账限额
    mapping (address => mapping (address => uint256)) _allowance;

    //帐户的资金冻结
    mapping (address => bool) public _frozen;

    //-----------------------------------------------
    // 初始化合约，并把所有代币都给CFO
    //-----------------------------------------------
    //   @param initialSupply 发行总量
    //   @param tokenName     代币名称
    //   @param tokenSymbol   代币符号
    //-----------------------------------------------
    constructor(uint256 initialSupply,string tokenName,string tokenSymbol) public
    {
        // validate input
        require(bytes(tokenName).length > 0 && bytes(tokenSymbol).length > 0);

        _token  = msg.sender;
        _cfo    = msg.sender;

        _supply = initialSupply * 10 ** uint256(decimals);
        _balances[_cfo] = _supply;

        name   = tokenName;
        symbol = tokenSymbol;
    }

    //-----------------------------------------------
    // 判断合约调用者是否 CFO
    //-----------------------------------------------
    modifier onlyCFO()
    {
        require(msg.sender == _cfo);
        _;
    }

    //-----------------------------------------------
    // 判断合约调用者是否 Ctrl Token
    //-----------------------------------------------
    modifier onlyCtrlToken()
    {
        require(msg.sender == _token);
        _;
    }

    //-----------------------------------------------
    // 获取货币供应量
    //-----------------------------------------------
    function totalSupply() public constant returns (uint256)
    {
        return _supply;
    }

    //-----------------------------------------------
    // 查询账户余额
    //-----------------------------------------------
    // @param  src 帐户地址
    //-----------------------------------------------
    function balanceOf(address src) public constant returns (uint256)
    {
        return _balances[src];
    }

    //-----------------------------------------------
    // 查询账户转账限额
    //-----------------------------------------------
    // @param  src 来源帐户地址
    // @param  dst 目标帐户地址
    //-----------------------------------------------
    function allowance(address src, address dst) public constant returns (uint256)
    {
        return _allowance[src][dst];
    }

    //-----------------------------------------------
    // 账户转账
    //-----------------------------------------------
    // @param  dst 目标帐户地址
    // @param  wad 转账金额
    //-----------------------------------------------
    function transfer(address dst, uint wad) public returns (bool)
    {
        //检查冻结帐户
        require(!_frozen[msg.sender]);
        require(!_frozen[dst]);

        //检查帐户余额
        require(_balances[msg.sender] >= wad);

        _balances[msg.sender] = sub(_balances[msg.sender],wad);
        _balances[dst]        = add(_balances[dst], wad);

        emit Transfer(msg.sender, dst, wad);

        return true;
    }


    //-----------------------------------------------
    // 账户转账带检查限额
    //-----------------------------------------------
    // @param  src 来源帐户地址
    // @param  dst 目标帐户地址
    // @param  wad 转账金额
    //-----------------------------------------------
    function transferFrom(address src, address dst, uint wad) public returns (bool)
    {
        //检查冻结帐户
        require(!_frozen[msg.sender]);
        require(!_frozen[dst]);

        //检查帐户余额
        require(_balances[src] >= wad);

        //检查帐户限额
        require(_allowance[src][msg.sender] >= wad);

        _allowance[src][msg.sender] = sub(_allowance[src][msg.sender],wad);

        _balances[src] = sub(_balances[src],wad);
        _balances[dst] = add(_balances[dst],wad);

        //转账事件
        emit Transfer(src, dst, wad);

        return true;
    }

    //-----------------------------------------------
    // 设置转账限额
    //-----------------------------------------------
    // @param  dst 目标帐户地址
    // @param  wad 限制金额
    //-----------------------------------------------
    function approve(address dst, uint256 wad) public returns (bool)
    {
        _allowance[msg.sender][dst] = wad;

        //设置事件
        emit Approval(msg.sender, dst, wad);
        return true;
    }

    //-----------------------------------------------
    // 设置自动累计转账限额
    //-----------------------------------------------
    // @param  dst 目标帐户地址
    // @param  wad 限制金额
    //-----------------------------------------------
    function approveAuto(address src, uint256 wad) onlyCtrlToken public returns (bool)
    {
        _allowance[src][msg.sender] = wad;
        return true;
    }

    //-----------------------------------------------
    // 设置 CTRL TOKEN 地址
    //-----------------------------------------------
    // @param  token 新的CTRL TOKEN地址
    //-----------------------------------------------
    function setCtrlToken(address NewToken) onlyCFO public returns (bool)
    {
        if (NewToken != _token)
        {
            _token = NewToken;
            return true;
        }
        else
        {
            return false;
        }
    }

    //-----------------------------------------------
    // 任命新的CFO
    //-----------------------------------------------
    // @param  newCFO 新的CFO帐户地址
    //-----------------------------------------------
    function appointNewCFO(address newCFO) onlyCFO public returns (bool)
    {
        if (newCFO != _cfo)
        {
            _cfo = newCFO;
            return true;
        }
        else
        {
            return false;
        }
    }

    //-----------------------------------------------
    // 冻结帐户
    //-----------------------------------------------
    // @param  dst  目标帐户地址
    // @param  flag 冻结
    //-----------------------------------------------
    function freeze(address dst, bool flag) onlyCFO public returns (bool)
    {
        _frozen[dst] = flag;

        //冻结帐户事件
        emit FreezeEvent(dst, flag);
        return true;
    }

    //-----------------------------------------------
    // 铸造代币
    //-----------------------------------------------
    // @param  dst  目标帐户地址
    // @param  wad  铸造金额
    //-----------------------------------------------
    function mint(address dst, uint256 wad) onlyCFO public returns (bool)
    {
        //目标帐户地址铸造代币,同时更新总量
        _balances[dst] = add(_balances[dst],wad);
        _supply        = add(_supply,wad);

        //铸造代币事件
        emit MintEvent(dst, wad);
        return true;
    }

    //-----------------------------------------------
    // 销毁代币
    //-----------------------------------------------
    // @param  dst  目标帐户地址
    // @param  wad  销毁金额
    //-----------------------------------------------
    function melt(address dst, uint256 wad) onlyCFO public returns (bool)
    {
        //检查帐户余额
        require(_balances[dst] >= wad);

        //销毁目标帐户地址代币,同时更新总量
        _balances[dst] = sub(_balances[dst],wad);
        _supply        = sub(_supply,wad);

        //销毁代币事件
        emit MeltEvent(dst, wad);
        return true;
    }
}