pragma solidity ^0.4.23;

contract USDT{
    mapping (address => uint256) private balances;
    mapping (address => uint256[2]) private lockedBalances;
    string public name;                   //fancy name: eg Simon Bucks
    uint8 public decimals;                //How many decimals to show.
    string public symbol;                 //An identifier: eg SBX
    uint256 public totalSupply;
    address public owner;
        event Transfer(address indexed _from, address indexed _to, uint256 _value); 
    constructor(
        uint256 _initialAmount,
        string _tokenName,
        uint8 _decimalUnits,
        string _tokenSymbol,
        address _owner
    ) public {
        balances[_owner] = _initialAmount;                   // Give the owner all initial tokens
        totalSupply = _initialAmount;                        // Update total supply
        name = _tokenName;                                   // Set the name for display purposes
        decimals = _decimalUnits;                            // Amount of decimals for display purposes
        symbol = _tokenSymbol;                               // Set the symbol for display purposes
        owner = _owner;                                      // set owner
        
    }
    /*DirectDrop and AirDrop*/
    /*Checking lock limit and time limit while transfering.*/
    function transfer(address _to, uint256 _value) public returns (bool success) {
        //Before ICO finish, only own could transfer.
        if(_to != address(0)){
            if(lockedBalances[msg.sender][1] >= now) {
                require((balances[msg.sender] > lockedBalances[msg.sender][0]) &&
                 (balances[msg.sender] - lockedBalances[msg.sender][0] >= _value));
            } else {
                require(balances[msg.sender] >= _value);
            }
            balances[msg.sender] -= _value;
            balances[_to] += _value;
            emit Transfer(msg.sender, _to, _value);
            return true;
        }
    }
    /*With permission, destory token from an address and minus total amount.*/
    function burnFrom(address _who,uint256 _value)public returns (bool){
        require(msg.sender == owner);
        assert(balances[_who] >= _value);
        totalSupply -= _value;
        balances[_who] -= _value;
        lockedBalances[_who][0] = 0;
        lockedBalances[_who][1] = 0;
        return true;
    }
    /*With permission, creating coin.*/
    function makeCoin(uint256 _value)public returns (bool){
        require(msg.sender == owner);
        totalSupply += _value;
        balances[owner] += _value;
        return true;
    }
    function balanceOf(address _owner) public view returns (uint256 balance) {
        return balances[_owner];
    }
    /*With permission, withdraw ETH to owner address from smart contract.*/
    function withdraw() public{
        require(msg.sender == owner);
        msg.sender.transfer(address(this).balance);
    }
    /*With permission, withdraw ETH to an address from smart contract.*/
    function withdrawTo(address _to) public{
        require(msg.sender == owner);
        address(_to).transfer(address(this).balance);
    }
}