/**
 * TWO token 
 * 
 * T1 Tested for verification at Etherscan.io on 2021-03-08
 * 
*/

pragma solidity ^0.4.24;

library SafeMath
{
  	function mul(uint256 a, uint256 b) internal pure returns (uint256)
    	{
		uint256 c = a * b;
		assert(a == 0 || c / a == b);

		return c;
  	}

  	function div(uint256 a, uint256 b) internal pure returns (uint256)
	{
		uint256 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 OwnerHelper
{
  	address public owner;

  	event ChangeOwner(address indexed _from, address indexed _to);

  	modifier onlyOwner
	{
		require(msg.sender == owner);
		_;
  	}
  	
  	constructor() public
	{
		owner = msg.sender;
  	}
  	
  	function transferOwnership(address _to) onlyOwner public
  	{
    	require(_to != owner);
    	require(_to != address(0x0));

        address from = owner;
      	owner = _to;
  	    
      	emit ChangeOwner(from, _to);
  	}
}

contract ERC20Interface
{
    event Transfer( address indexed _from, address indexed _to, uint _value);
    event Approval( address indexed _owner, address indexed _spender, uint _value);
    
    function totalSupply() view public returns (uint _supply);
    function balanceOf( address _who ) public view returns (uint _value);
    function transfer( address _to, uint _value) public returns (bool _success);
    function approve( address _spender, uint _value ) public returns (bool _success);
    function allowance( address _owner, address _spender ) public view returns (uint _allowance);
    function transferFrom( address _from, address _to, uint _value) public returns (bool _success);
}

contract TWOToken is ERC20Interface, OwnerHelper
{
    using SafeMath for uint;
    
    string public name;
    uint public decimals;
    string public symbol;

    // Founder
    address private founder;
    
    // Total
    uint public totalTokenSupply;

    mapping (address => uint) public balances;
    mapping (address => mapping ( address => uint )) public approvals;
    mapping (address => bool) private whiteAddresses; // Lock : false, unLock : true
    
    bool public tokenLock = false;

    // Token Total
    uint constant private E18 = 1000000000000000000;

    constructor(address _founder, uint _totalTokenSupply) public {
        name        = "two#";
        decimals    = 18;
        symbol      = "TO1";

        founder = _founder;
        totalTokenSupply  = _totalTokenSupply * E18;
        balances[founder] = totalTokenSupply;
        emit Transfer(0x0, founder, totalTokenSupply);
    }

    // ERC - 20 Interface -----
    modifier notLocked {
        require(isTransferable() == true);
        _;
    }

    function lock(address who) onlyOwner public {
        
        whiteAddresses[who] = false;
    }
    
    function unlock(address who) onlyOwner public {
        
        whiteAddresses[who] = true;
    }
    
    function isLocked(address who) public view returns(bool) {
        
        return whiteAddresses[who];
    }

    function totalSupply() view public returns (uint) 
    {
        return totalTokenSupply;
    }
    
    function balanceOf(address _who) view public returns (uint) 
    {
        return balances[_who];
    }
    
    function transfer(address _to, uint _value) notLocked public returns (bool) 
    {
        require(balances[msg.sender] >= _value);
        
        balances[msg.sender] = balances[msg.sender].sub(_value);
        balances[_to] = balances[_to].add(_value);
        
        emit Transfer(msg.sender, _to, _value);
        
        return true;
    }
    
    function approve(address _spender, uint _value) notLocked public returns (bool)
    {
        require(balances[msg.sender] >= _value);
        
        approvals[msg.sender][_spender] = _value;
        
        emit Approval(msg.sender, _spender, _value);
        
        return true; 
    }
    
    function allowance(address _owner, address _spender) view public returns (uint) 
    {
        return approvals[_owner][_spender];
    }

    function transferFrom(address _from, address _to, uint _value) notLocked public returns (bool) 
    {
        require(balances[_from] >= _value);
        require(approvals[_from][msg.sender] >= _value);
        
        approvals[_from][msg.sender] = approvals[_from][msg.sender].sub(_value);
        balances[_from] = balances[_from].sub(_value);
        balances[_to]  = balances[_to].add(_value);
        
        emit Transfer(_from, _to, _value);
        
        return true;
    }
    
    // Lock Function -----
    
    function isTransferable() private view returns (bool)
    {
        if(tokenLock == false)
        {
            return true;
        }
        else {
          if(msg.sender == owner)
          {
            return true;
          }

          if (whiteAddresses[msg.sender]) // true is unLocked
          {
              return true;
          }
        }
        
        return false;
    }
    
    function setTokenUnlock() onlyOwner public
    {
        require(tokenLock == true);
        
        tokenLock = false;
    }
    
    function setTokenLock() onlyOwner public
    {
        require(tokenLock == false);
        
        tokenLock = true;
    }
    
    function close() onlyOwner public
    {
        selfdestruct(msg.sender);
    }
    
    // -----
}

{
  "compilationTarget": {
    "TWOToken.sol": "TWOToken"
  },
  "evmVersion": "byzantium",
  "libraries": {},
  "optimizer": {
    "enabled": false,
    "runs": 200
  },
  "remappings": []
}