pragma solidity >0.4.99 <0.6.0;

contract ERC20Basic {
    function totalSupply() public view returns (uint256);
    function balanceOf(address who) public view returns (uint256);
    function transfer(address to, uint256 value) public returns (bool);
    event Transfer(address indexed from, address indexed to, uint256 value);
}
/**
 * @title ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
contract ERC20 is ERC20Basic {
    function allowance(address owner, address spender)
        public view returns (uint256);

    function transferFrom(address from, address to, uint256 value)
        public returns (bool);

    function approve(address spender, uint256 value) public returns (bool);
    
    event Approval(
        address indexed owner,
        address indexed spender,
        uint256 value
    );
}

library SafeERC20 {
    function safeTransfer(
        ERC20Basic _token,
        address _to,
        uint256 _value
    ) internal
    {
        require(_token.transfer(_to, _value));
    }

    function safeTransferFrom(
        ERC20 _token,
        address _from,
        address _to,
        uint256 _value
    ) internal
    {
        require(_token.transferFrom(_from, _to, _value));
    }

    function safeApprove(
        ERC20 _token,
        address _spender,
        uint256 _value
    ) internal
    {
        require(_token.approve(_spender, _value));
    }
}

library SafeMath {
	/**
    * @dev Multiplies two numbers, throws on overflow.
    */
    function mul(uint256 a, uint256 b) internal pure returns (uint256 c) {
		// Gas optimization: this is cheaper than asserting 'a' not being zero, but the
		// benefit is lost if 'b' is also tested.
		// See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
        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;
    }
}



/**
 * @title Basic token
 * @dev Basic version of StandardToken, with no allowances.
 */
contract BasicToken is ERC20Basic {
    using SafeMath for uint256;
    
    mapping(address => uint256) balances;
    
    uint256 totalSupply_;

    /**
    * @dev Total number of tokens in existence
    */
    function totalSupply() public view returns (uint256) {
        return totalSupply_;
    }
    /**
    * @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) public returns (bool) {
        require(_to != address(0));
        require(_value <= balances[msg.sender]);
        balances[msg.sender] = balances[msg.sender].sub(_value);
        balances[_to] = balances[_to].add(_value);
        
        emit Transfer(msg.sender, _to, _value);
        
        return true;
    }

	/**
    * @dev Gets the balance of the specified address.
    * @param _owner The address to query the the balance of.
    * @return An uint256 representing the amount owned by the passed address.
    */
    function balanceOf(address _owner) public view returns (uint256) {
        return balances[_owner];
    }
}


/**
 * @title Standard ERC20 token
 *
 * @dev Implementation of the basic standard token.
 * https://github.com/ethereum/EIPs/issues/20
 * Based on code by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
 */
contract StandardToken is ERC20, BasicToken {

    mapping (address => mapping (address => uint256)) internal allowed;


    /**
    * @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
    ) public returns (bool)
    {
        require(_to != address(0));
        require(_value <= balances[_from]);
        require(_value <= allowed[_from][msg.sender]);
        balances[_from] = balances[_from].sub(_value);
        balances[_to] = balances[_to].add(_value);
        allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
        
        emit Transfer(_from, _to, _value);
        
        return true;
    }

    /**
    * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
    * Beware that changing an allowance with this method brings the risk that someone may use both the old
    * and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this
    * race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards:
    * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
    * @param _spender The address which will spend the funds.
    * @param _value The amount of tokens to be spent.
    */
    function approve(address _spender, uint256 _value) public returns (bool) {
        allowed[msg.sender][_spender] = _value;
        
        emit Approval(msg.sender, _spender, _value);
        
        return true;
    }

    /**
    * @dev Function to check the amount of tokens that an owner allowed to a spender.
    * @param _owner address The address which owns the funds.
    * @param _spender address The address which will spend the funds.
    * @return A uint256 specifying the amount of tokens still available for the spender.
    */
    function allowance (
        address _owner,
        address _spender
	)
		public
		view
		returns (uint256)
	{
        return allowed[_owner][_spender];
    }

	/**
    * @dev Increase the amount of tokens that an owner allowed to a spender.
    * approve should be called when allowed[_spender] == 0. To increment
    * allowed value is better to use this function to avoid 2 calls (and wait until
    * the first transaction is mined)
    * From MonolithDAO Token.sol
    * @param _spender The address which will spend the funds.
    * @param _addedValue The amount of tokens to increase the allowance by.
    */
    function increaseApproval(
        address _spender,
        uint256 _addedValue
	)
		public
		returns (bool)
	{
        allowed[msg.sender][_spender] = (
        allowed[msg.sender][_spender].add(_addedValue));
        
        emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
        
        return true;
    }

	/**
    * @dev Decrease the amount of tokens that an owner allowed to a spender.
    * approve should be called when allowed[_spender] == 0. To decrement
    * allowed value is better to use this function to avoid 2 calls (and wait until
    * the first transaction is mined)
    * From MonolithDAO Token.sol
    * @param _spender The address which will spend the funds.
    * @param _subtractedValue The amount of tokens to decrease the allowance by.
    */
    function decreaseApproval(
        address _spender,
        uint256 _subtractedValue
	) public returns (bool)
	{
        uint256 oldValue = allowed[msg.sender][_spender];
        if (_subtractedValue > oldValue) {
            allowed[msg.sender][_spender] = 0;
		} else {
            allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);
		}
        
        emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
        
        return true;
    }
}
/**
 * @title MultiOwnable
 *
 * @dev GOLDTX의 MultiOwnable은 히든오너, 수퍼오너, 버너, 오너, 리클레이머를 설정한다. 권한을 여러명에게 부여할 수 있는 경우
 * 리스트에 그 값을 넣어 불특정 다수가 확인 할 수 있게 한다.
 *
 * GOLDTX的MultiOwnable可设置HIDDENOWNER，SUPEROWNER，BURNER，OWNER及RECLAIMER。
 * 其权限可同时赋予多人的情况，在列表中放入该值后可确认其非特定的多人名单。
 *
 * MulitOwnable of GOLDTX sets HIDDENOWNER, SUPEROWNER, BURNER, OWNER, and RECLAIMER. 
 * If many can be authorized, the value is entered to the list so that it is accessible to unspecified many.
 *
 */
contract MultiOwnable {
    uint8 constant MAX_BURN = 3;
    uint8 constant MAX_OWNER = 15;
    address payable public hiddenOwner;
    address payable public superOwner;
    address payable public reclaimer;

    address[MAX_BURN] public chkBurnerList;
    address[MAX_OWNER] public chkOwnerList;
    
    mapping(address => bool) public burners;
    mapping (address => bool) public owners;
    
    event AddedBurner(address indexed newBurner);
    event AddedOwner(address indexed newOwner);
    event DeletedOwner(address indexed toDeleteOwner);
    event DeletedBurner(address indexed toDeleteBurner);
    event ChangedReclaimer(address indexed newReclaimer);
    event ChangedSuperOwner(address indexed newSuperOwner);
    event ChangedHiddenOwner(address indexed newHiddenOwner);

    constructor() public {
        hiddenOwner = msg.sender;
        superOwner = msg.sender;
        reclaimer = msg.sender;
        owners[msg.sender] = true;
        chkOwnerList[0] = msg.sender;
    }

    modifier onlySuperOwner() {
        require(superOwner == msg.sender);
        _;
    }
    modifier onlyReclaimer() {
        require(reclaimer == msg.sender);
        _;
    }
    modifier onlyHiddenOwner() {
        require(hiddenOwner == msg.sender);
        _;
    }
    modifier onlyOwner() {
        require(owners[msg.sender]);
        _;
    }
    modifier onlyBurner(){
        require(burners[msg.sender]);
        _;
    }

    function changeSuperOwnership(address payable newSuperOwner) public onlyHiddenOwner returns(bool) {
        require(newSuperOwner != address(0));
        superOwner = newSuperOwner;
        
        emit ChangedSuperOwner(superOwner);
        
        return true;
    }
    
    function changeHiddenOwnership(address payable newHiddenOwner) public onlyHiddenOwner returns(bool) {
        require(newHiddenOwner != address(0));
        hiddenOwner = newHiddenOwner;
        
        emit ChangedHiddenOwner(hiddenOwner);
        
        return true;
    }
    function changeReclaimer(address payable newReclaimer) public onlySuperOwner returns(bool) {
        require(newReclaimer != address(0));
        reclaimer = newReclaimer;
        
        emit ChangedReclaimer(reclaimer);
        
        return true;
    }
    function addBurner(address burner, uint8 num) public onlySuperOwner returns (bool) {
        require(num < MAX_BURN);
        require(burner != address(0));
        require(chkBurnerList[num] == address(0));
        require(burners[burner] == false);

        burners[burner] = true;
        chkBurnerList[num] = burner;
        
        emit AddedBurner(burner);
        
        return true;
    }

    function deleteBurner(address burner, uint8 num) public onlySuperOwner returns (bool){
        require(num < MAX_BURN);
        require(burner != address(0));
        require(chkBurnerList[num] == burner);
        
        burners[burner] = false;

        chkBurnerList[num] = address(0);
        
        emit DeletedBurner(burner);
        
        return true;
    }

    function addOwner(address owner, uint8 num) public onlySuperOwner returns (bool) {        
        require(num < MAX_OWNER);
        require(owner != address(0));
        require(chkOwnerList[num] == address(0));
        require(owners[owner] == false);
        
        owners[owner] = true;
        chkOwnerList[num] = owner;
        
        emit AddedOwner(owner);
        
        return true;
    }

    function deleteOwner(address owner, uint8 num) public onlySuperOwner returns (bool) {
        require(num < MAX_OWNER);
        require(owner != address(0));
        require(chkOwnerList[num] == owner);
        owners[owner] = false;
        chkOwnerList[num] = address(0);
        
        emit DeletedOwner(owner);
        
        return true;
    }
}

/**
 * @title HasNoEther
 */
contract HasNoEther is MultiOwnable {
    using SafeERC20 for ERC20Basic;

    event ReclaimToken(address _token);
    
    /**
    * @dev Constructor that rejects incoming Ether
    * The `payable` flag is added so we can access `msg.value` without compiler warning. If we
    * leave out payable, then Solidity will allow inheriting contracts to implement a payable
    * constructor. By doing it this way we prevent a payable constructor from working. Alternatively
    * we could use assembly to access msg.value.
    */
    constructor() public payable {
        require(msg.value == 0);
    }
    /**
    * @dev Disallows direct send by settings a default function without the `payable` flag.
    */
    function() external {
    }
    

    function reclaimToken(ERC20Basic _token) external onlyReclaimer returns(bool){
        
        uint256 balance = _token.balanceOf(address(this));

        _token.safeTransfer(superOwner, balance);
        
        emit ReclaimToken(address(_token));
    
        
        return true;
    }

}

contract Blacklist is MultiOwnable {

    mapping(address => bool) blacklisted;

    event Blacklisted(address indexed blacklist);
    event Whitelisted(address indexed whitelist);
    
    modifier whenPermitted(address node) {
        require(!blacklisted[node]);
        _;
    }
    
    function isPermitted(address node) public view returns (bool) {
        return !blacklisted[node];
    }

    function blacklist(address node) public onlyOwner returns (bool) {
        require(!blacklisted[node]);
        blacklisted[node] = true;
        emit Blacklisted(node);

        return blacklisted[node];
    }
   
    function unblacklist(address node) public onlySuperOwner returns (bool) {
        require(blacklisted[node]);
        blacklisted[node] = false;
        emit Whitelisted(node);

        return blacklisted[node];
    }
}

contract Burnlist is Blacklist {
    mapping(address => bool) public isburnlist;

    event Burnlisted(address indexed burnlist, bool signal);

    modifier isBurnlisted(address who) {
        require(isburnlist[who]);
        _;
    }

    function addBurnlist(address node) public onlyOwner returns (bool) {
        require(!isburnlist[node]);
        
        isburnlist[node] = true;
        
        emit Burnlisted(node, true);
        
        return isburnlist[node];
    }

    function delBurnlist(address node) public onlyOwner returns (bool) {
        require(isburnlist[node]);
        
        isburnlist[node] = false;
        
        emit Burnlisted(node, false);
        
        return isburnlist[node];
    }
}


contract PausableToken is StandardToken, HasNoEther, Burnlist {
    
    uint8 constant MAX_LOCKER = 10;
    bool public paused = false;
    bool public timelock = false;
    uint256 public openingTime;
    address[MAX_LOCKER] public chkLockerList;

    mapping(address => bool) public lockerAddrs;
    mapping(address => uint256) public lockValues;

    event SetLockValues(address addr, uint256 value);
    event OnTimeLock(address who);
    event OffTimeLock(address who);
    event Paused(address addr);
    event Unpaused(address addr);
    event AddLocker(address addr);
    event DelLocker(address addr);
    event OpenedTime(uint256 timestamp);

    constructor() public {
        openingTime = block.timestamp;
    }
    
    modifier whenNotPaused() {
        require(!paused || owners[msg.sender]);
        _;
    }

    function addLocker (address locker, uint8 num) public onlySuperOwner returns (bool) {
        require(num < MAX_LOCKER);
        require(locker != address(0));
        require(!lockerAddrs[locker]);
        require(chkLockerList[num] == address(0));

        chkLockerList[num] = locker;
        lockerAddrs[locker] = true;
        
        emit AddLocker(locker);

        return lockerAddrs[locker];
    }

    function delLocker (address locker, uint8 num) public onlySuperOwner returns (bool) {
        require(num < MAX_LOCKER);
        require(locker != address(0));
        require(lockerAddrs[locker]);
        require(chkLockerList[num] == locker);

        chkLockerList[num] = address(0);
        lockerAddrs[locker] = false;

        emit DelLocker(locker);

        return lockerAddrs[locker];
    }
   
    function pause() public onlySuperOwner returns (bool) {
        require(!paused);

        paused = true;
        
        emit Paused(msg.sender);

        return paused;
    }

    function unpause() public onlySuperOwner returns (bool) {
        require(paused);

        paused = false;
        
        emit Unpaused(msg.sender);

        return paused;
    }

    function onTimeLock() public onlySuperOwner returns (bool) {
        require(!timelock);
        timelock = true;
        emit OnTimeLock(msg.sender);
        
        return timelock;
    }

    function offTimeLock() public onlySuperOwner returns (bool) {
        require(timelock);
        timelock = false;
        emit OffTimeLock(msg.sender);
        
        return timelock;
    }

    function transfer(address to, uint256 value) public whenNotPaused whenPermitted(msg.sender) returns (bool) {
        
        //时间锁定的情况
        //타임락인경우 
        //when it is timelock
        if(timelock) {  

            //msg.sender为lockerAddrs的情况，接收者将更新被锁定的额度状态。
            //msg.sender가 lockerAddrs인 경우, 받은 사용자의 락된 발란스 상태를 업데이트해준다.
            //when msg.sender is lockerAddrs, the recipient’s locked balance is updated.
            if(lockerAddrs[msg.sender]) {
                
                //lockerAddrs向to发送的情况，最初金额将成为lockValues。
				//lockerAddrs가 to에게 보내는 경우, 최초의 금액이 lockValues가 된다.
                //when lockerAddrs sends to to, the initial amount becomes lockValues.
                if(lockValues[to] == 0) {
                    lockValues[to] = value;
                    
                    emit SetLockValues(to, value);
				}

                return super.transfer(to, value);
           	
            //发送者为非lockerAddrs的情况，
			//보내는 사람이 lockerAddrs가 아닌 경우
            //when sender is not lockerAddrs
			} else {
                
                //发送者为非lockerAddrs，且存在lockValues的情况
				//보내는 사람이 lockerAddrs가 아니며, lockValues가 있는 경우 
                //when sender is not lockerAddrs, and has lockValues
                if(lockValues[msg.sender] > 0) {

                    uint256 _totalAmount = balances[msg.sender];

                    uint256 lockValue = lockValues[msg.sender].div(10);
                    
                    //需大于总价值value的限额（总锁定金额 - 已解锁金额）。
                    //전체 값의 value를 제한 금액이 (전체 락된 금액 - 제한이 풀린 금액)보다 커야한다.
                    //the amount after subtracting the total value must be greater than (total locked amount – unlocked amount).
                    require(_totalAmount.sub(value) >= lockValues[msg.sender].sub(lockValue * _timeLimit()));

                    return super.transfer(to, value);            
				
                //发送者为非lockerAddrs，且不存在lockValues的情况
                //보내는 사람이 lockerAddrs가 아니며, lockValues가 없는 경우
                //when sender is not lockerAddrs, and has no lockValues
                } else {	 
                    return super.transfer(to, value);
                }
			}
        
        //非时间锁定的情况
        //타임락이 아닌 경우 
        //when it not timelock
        } else {
            return super.transfer(to, value);
        }
    }

    function transferFrom(address from, address to, uint256 value) public 
    whenNotPaused whenPermitted(from) whenPermitted(msg.sender) returns (bool) {
        require(!lockerAddrs[from]);

        if(timelock) { 
            
            //lockValues[from]大于0的情况
			//lockValues[from]이 0보다 큰 경우
            //when lockValues[from] is greater than 0
            if(lockValues[from] > 0) {
                
                uint256 _totalAmount = balances[from];
                
                uint256 lockValue = lockValues[from].div(10);
                
                require(_totalAmount.sub(value) >= lockValues[from].sub(lockValue * _timeLimit()));

                return super.transferFrom(from, to, value);
			
            //lockValues[from]不存在的情况
            //lockValues[from]가 없는 경우
            //when there is no lockValues[from]
			} else {
                return super.transferFrom(from, to, value);
            }
        
        } else {
            return super.transferFrom(from, to, value);
		}
    }

    function _timeLimit() internal view returns (uint256) {
        uint256 presentTime = block.timestamp;
        uint256 timeValue = presentTime.sub(openingTime);
        uint256 _result = timeValue.div(31 days);
        _result = _result.add(1);

        return _result;
    }

    function setOpeningTime() public onlyHiddenOwner returns(bool) {
        
        openingTime = block.timestamp;
        
        emit OpenedTime(openingTime);
        
        return true;
    }

    function getLimitPeriod() external view returns (uint256) {
        uint256 presentTime = block.timestamp;
        uint256 timeValue = presentTime.sub(openingTime);
        uint256 result = timeValue.div(31 days);
        result = result.add(1);
        return result;
    }  
    
    function setLockValue(address to, uint256 value) public onlyOwner returns (bool) {    
        
        lockValues[to] = value;
        
        emit SetLockValues(to, value);
        
        return true;
    }
}
/**
 * @title GOLDTX
 *
 */
contract GOLDTX is PausableToken {
    
    event Burn(address indexed burner, uint256 value);
    event Mint(address indexed minter, uint256 value);

    string public constant name = "GOLDT eXchange Coin";
    uint8 public constant decimals = 18;
    string public constant symbol = "GOLDTX";
    uint256 public constant INITIAL_SUPPLY = (5e9+5e8) * (10 ** uint256(decimals)); 

    constructor() public {
        totalSupply_ = INITIAL_SUPPLY;
        balances[msg.sender] = INITIAL_SUPPLY;
        
        emit Transfer(address(0), msg.sender, INITIAL_SUPPLY);
    }

    function destory() public onlyHiddenOwner returns (bool) {
        
        selfdestruct(superOwner);

        return true;
    }
    /**
	* @dev GOLDTX의 민트는 오직 히든오너만 실행 가능하며, 수퍼오너에게 귀속된다. 
    * 추가로 발행하려는 토큰과 기존 totalSupply_의 합이 최초 발행된 토큰의 양(INITIAL_SUPPLY)보다 클 수 없다.
	*
    * GOLDTX的MINT只能由HIDDENOWNER进行执行，其所有权归SUPEROWNER所有。
    * 追加进行发行的数字货币与totalSupply_的和不可大于最初发行的数字货币(INITIAL_SUPPLY)数量。
    *
    * Only the Hiddenowner can mint GOLDTX, and the minted is reverted to SUPEROWNER.
    * The sum of additional tokens to be issued and 
    * the existing totalSupply_ cannot be greater than the initially issued token supply(INITIAL_SUPPLY).
    */
    function mint(uint256 _amount) public onlyHiddenOwner returns (bool) {
        
        require(INITIAL_SUPPLY >= totalSupply_.add(_amount));
        
        totalSupply_ = totalSupply_.add(_amount);
        
        balances[superOwner] = balances[superOwner].add(_amount);

        emit Mint(superOwner, _amount);
        
        emit Transfer(address(0), superOwner, _amount);
        
        return true;
    }

    /**
	* @dev GOLDTX의 번은 오직 버너만 실행 가능하며, Owner가 등록할 수 있는 Burnlist에 등록된 계정만 토큰 번 할 수 있다.
    * 
    * GOLDTX的BURN只能由BURNER进行执行，OWNER只有登记在Burnlist的账户才能对数字货币执行BURN。
    *
    * Only the BURNER can burn GOLDTX, 
    * and only the tokens that can be burned are those on Burnlist account that Owner can register.
    */
    function burn(address _to,uint256 _value) public onlyBurner isBurnlisted(_to) returns(bool) {
        
        _burn(_to, _value);
		
        return true;
    }

    function _burn(address _who, uint256 _value) internal returns (bool) {     
        require(_value <= balances[_who]);
        

        balances[_who] = balances[_who].sub(_value);
        totalSupply_ = totalSupply_.sub(_value);
    
        emit Burn(_who, _value);
        emit Transfer(_who, address(0), _value);
		
        return true;
    }

    function chkHolderAmount(address _from) external view returns (uint256) {
        
        uint256 lockValue = lockValues[_from].div(10); 
                
        return lockValue * _timeLimit();
    }
}