pragma solidity ^0.4.24;

// File: contracts/openzeppelin/ownership/Ownable.sol

/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
  address private _owner;


  event OwnershipRenounced(address indexed previousOwner);
  event OwnershipTransferred(
    address indexed previousOwner,
    address indexed newOwner
  );


  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */
  constructor() public {
    _owner = msg.sender;
  }

  /**
   * @return the address of the owner.
   */
  function owner() public view returns(address) {
    return _owner;
  }

  /**
   * @dev Throws if called by any account other than the owner.
   */
  modifier onlyOwner() {
    require(isOwner());
    _;
  }

  /**
   * @return true if `msg.sender` is the owner of the contract.
   */
  function isOwner() public view returns(bool) {
    return msg.sender == _owner;
  }

  /**
   * @dev Allows the current owner to relinquish control of the contract.
   * @notice Renouncing to ownership will leave the contract without an owner.
   * It will not be possible to call the functions with the `onlyOwner`
   * modifier anymore.
   */
  function renounceOwnership() public onlyOwner {
    emit OwnershipRenounced(_owner);
    _owner = address(0);
  }

  /**
   * @dev Allows the current owner to transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function transferOwnership(address newOwner) public onlyOwner {
    _transferOwnership(newOwner);
  }

  /**
   * @dev Transfers control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function _transferOwnership(address newOwner) internal {
    require(newOwner != address(0));
    emit OwnershipTransferred(_owner, newOwner);
    _owner = newOwner;
  }
}

// File: contracts/Administratable.sol

// Lee, July 29, 2018
pragma solidity 0.4.24;

// August 21, 2018
// remove all admin code.


contract Administratable is Ownable {
	mapping (address => bool) public superAdmins;

	event AddSuperAdmin(address indexed admin);
	event RemoveSuperAdmin(address indexed admin);


    modifier validateAddress( address _addr )
    {
        require(_addr != address(0x0));
        require(_addr != address(this));
        _;
    }

	modifier onlySuperAdmins {
		require(msg.sender == owner() || superAdmins[msg.sender]);
		_;
	}

	function addSuperAdmin(address _admin) public onlyOwner validateAddress(_admin){
		require(!superAdmins[_admin]);
		superAdmins[_admin] = true;
		emit AddSuperAdmin(_admin);
	}

	function removeSuperAdmin(address _admin) public onlyOwner validateAddress(_admin){
		require(superAdmins[_admin]);
		superAdmins[_admin] = false;
		emit RemoveSuperAdmin(_admin);
	}
}

// File: contracts/TimeLockable.sol

// Lee, July 29, 2018
pragma solidity 0.4.24;


contract TimeLockable is Administratable{

    uint256 private constant ADVISOR_LOCKUP_END     = 1551398399; // 2019.02.28 23.59.59 (UTC)
    uint256 private constant TEAM_LOCKUP_END        = 1567295999; // 2019.08.31 23.59.59 (UTC)

    mapping (address => uint256) public timelockedAccounts;
    event LockedFunds(address indexed target, uint256 timelocked);

    modifier isNotTimeLocked() {
        require(now >= timelockedAccounts[msg.sender]);
        _;
    }

    modifier isNotTimeLockedFrom( address _from ) {
        require( now >= timelockedAccounts[_from] && now >= timelockedAccounts[msg.sender]);
        _;
    }

    function timeLockAdvisor(address _target) public onlySuperAdmins validateAddress(_target) {
        require(timelockedAccounts[_target] == 0);
        timelockedAccounts[_target] = ADVISOR_LOCKUP_END;
        emit LockedFunds(_target, ADVISOR_LOCKUP_END);
    }

    function timeLockTeam(address _target) public onlySuperAdmins validateAddress(_target) {
        require(timelockedAccounts[_target] == 0);
        timelockedAccounts[_target] = TEAM_LOCKUP_END;
        emit LockedFunds(_target, TEAM_LOCKUP_END);
    }
}

// File: contracts/Freezable.sol

// Lee, July 29, 2018
pragma solidity 0.4.24;


contract Freezable is Administratable {

    bool public frozenToken;
    mapping (address => bool) public frozenAccounts;

    event FrozenFunds(address indexed _target, bool _frozen);
    event FrozenToken(bool _frozen);

    modifier isNotFrozen( address _to ) {
        require(!frozenToken);
        require(!frozenAccounts[msg.sender] && !frozenAccounts[_to]);
        _;
    }

    modifier isNotFrozenFrom( address _from, address _to ) {
        require(!frozenToken);
        require(!frozenAccounts[msg.sender] && !frozenAccounts[_from] && !frozenAccounts[_to]);
        _;
    }

    function freezeAccount(address _target, bool _freeze) public onlySuperAdmins validateAddress(_target) {
        require(frozenAccounts[_target] != _freeze);
        frozenAccounts[_target] = _freeze;
        emit FrozenFunds(_target, _freeze);
    }

    function freezeToken(bool _freeze) public onlySuperAdmins {
        require(frozenToken != _freeze);
        frozenToken = _freeze;
        emit FrozenToken(frozenToken);
    }
}

// File: contracts/openzeppelin/token/ERC20/IERC20.sol

/**
 * @title ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
interface IERC20 {
  function totalSupply() external view returns (uint256);

  function balanceOf(address who) external view returns (uint256);

  function allowance(address owner, address spender)
    external view returns (uint256);

  function transfer(address to, uint256 value) external returns (bool);

  function approve(address spender, uint256 value)
    external returns (bool);

  function transferFrom(address from, address to, uint256 value)
    external returns (bool);

  event Transfer(
    address indexed from,
    address indexed to,
    uint256 value
  );

  event Approval(
    address indexed owner,
    address indexed spender,
    uint256 value
  );
}

// File: contracts/openzeppelin/math/SafeMath.sol

/**
 * @title SafeMath
 * @dev Math operations with safety checks that revert on error
 */
library SafeMath {

  /**
  * @dev Multiplies two numbers, reverts on overflow.
  */
  function mul(uint256 a, uint256 b) internal pure returns (uint256) {
    // Gas optimization: this is cheaper than requiring '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;
    }

    uint256 c = a * b;
    require(c / a == b);

    return c;
  }

  /**
  * @dev Integer division of two numbers truncating the quotient, reverts on division by zero.
  */
  function div(uint256 a, uint256 b) internal pure returns (uint256) {
    require(b > 0); // Solidity only automatically asserts 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 c;
  }

  /**
  * @dev Subtracts two numbers, reverts on overflow (i.e. if subtrahend is greater than minuend).
  */
  function sub(uint256 a, uint256 b) internal pure returns (uint256) {
    require(b <= a);
    uint256 c = a - b;

    return c;
  }

  /**
  * @dev Adds two numbers, reverts on overflow.
  */
  function add(uint256 a, uint256 b) internal pure returns (uint256) {
    uint256 c = a + b;
    require(c >= a);

    return c;
  }

  /**
  * @dev Divides two numbers and returns the remainder (unsigned integer modulo),
  * reverts when dividing by zero.
  */
  function mod(uint256 a, uint256 b) internal pure returns (uint256) {
    require(b != 0);
    return a % b;
  }
}

// File: contracts/openzeppelin/token/ERC20/ERC20.sol

/**
 * @title Standard ERC20 token
 *
 * @dev Implementation of the basic standard token.
 * https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20.md
 * Originally based on code by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
 */
contract ERC20 is IERC20 {
  using SafeMath for uint256;

  mapping (address => uint256) private _balances;

  mapping (address => mapping (address => uint256)) private _allowed;

  uint256 private _totalSupply;

  /**
  * @dev Total number of tokens in existence
  */
  function totalSupply() public view returns (uint256) {
    return _totalSupply;
  }

  /**
  * @dev Gets the balance of the specified address.
  * @param owner The address to query 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];
  }

  /**
   * @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 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(value <= _balances[msg.sender]);
    require(to != address(0));

    _balances[msg.sender] = _balances[msg.sender].sub(value);
    _balances[to] = _balances[to].add(value);
    emit Transfer(msg.sender, 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) {
    require(spender != address(0));

    _allowed[msg.sender][spender] = value;
    emit Approval(msg.sender, spender, 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
  )
    public
    returns (bool)
  {
    require(value <= _balances[from]);
    require(value <= _allowed[from][msg.sender]);
    require(to != address(0));

    _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 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 increaseAllowance(
    address spender,
    uint256 addedValue
  )
    public
    returns (bool)
  {
    require(spender != address(0));

    _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 decreaseAllowance(
    address spender,
    uint256 subtractedValue
  )
    public
    returns (bool)
  {
    require(spender != address(0));

    _allowed[msg.sender][spender] = (
      _allowed[msg.sender][spender].sub(subtractedValue));
    emit Approval(msg.sender, spender, _allowed[msg.sender][spender]);
    return true;
  }

  /**
   * @dev Internal function that mints an amount of the token and assigns it to
   * an account. This encapsulates the modification of balances such that the
   * proper events are emitted.
   * @param account The account that will receive the created tokens.
   * @param amount The amount that will be created.
   */
  function _mint(address account, uint256 amount) internal {
    require(account != 0);
    _totalSupply = _totalSupply.add(amount);
    _balances[account] = _balances[account].add(amount);
    emit Transfer(address(0), account, amount);
  }

  /**
   * @dev Internal function that burns an amount of the token of a given
   * account.
   * @param account The account whose tokens will be burnt.
   * @param amount The amount that will be burnt.
   */
  function _burn(address account, uint256 amount) internal {
    require(account != 0);
    require(amount <= _balances[account]);

    _totalSupply = _totalSupply.sub(amount);
    _balances[account] = _balances[account].sub(amount);
    emit Transfer(account, address(0), amount);
  }

  /**
   * @dev Internal function that burns an amount of the token of a given
   * account, deducting from the sender's allowance for said account. Uses the
   * internal burn function.
   * @param account The account whose tokens will be burnt.
   * @param amount The amount that will be burnt.
   */
  function _burnFrom(address account, uint256 amount) internal {
    require(amount <= _allowed[account][msg.sender]);

    // Should https://github.com/OpenZeppelin/zeppelin-solidity/issues/707 be accepted,
    // this function needs to emit an event with the updated approval.
    _allowed[account][msg.sender] = _allowed[account][msg.sender].sub(
      amount);
    _burn(account, amount);
  }
}

// File: contracts/openzeppelin/token/ERC20/ERC20Burnable.sol

/**
 * @title Burnable Token
 * @dev Token that can be irreversibly burned (destroyed).
 */
contract ERC20Burnable is ERC20 {

  /**
   * @dev Burns a specific amount of tokens.
   * @param value The amount of token to be burned.
   */
  function burn(uint256 value) public {
    _burn(msg.sender, value);
  }

  /**
   * @dev Burns a specific amount of tokens from the target address and decrements allowance
   * @param from address The address which you want to send tokens from
   * @param value uint256 The amount of token to be burned
   */
  function burnFrom(address from, uint256 value) public {
    _burnFrom(from, value);
  }

  /**
   * @dev Overrides ERC20._burn in order for burn and burnFrom to emit
   * an additional Burn event.
   */
  function _burn(address who, uint256 value) internal {
    super._burn(who, value);
  }
}

// File: contracts/XtockToken.sol

// Lee, July 29, 2018
pragma solidity 0.4.24;




contract XtockToken is ERC20Burnable, TimeLockable, Freezable
{
    string 	public 	constant name 		= "XtockToken";
    string 	public 	constant symbol 	= "XTX";
    uint8 	public 	constant decimals 	= 18;
    
    event Burn(address indexed _burner, uint _value);

    constructor( address _registry, uint _totalTokenAmount ) public
    {
        _mint(_registry, _totalTokenAmount);
        addSuperAdmin(_registry);
    }


    /**
    * @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, uint _value) public validateAddress(_to) isNotTimeLocked() isNotFrozen(_to) returns (bool) 
    {
        return super.transfer(_to, _value);
    }

    /**
    * @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, uint _value) public validateAddress(_to) isNotTimeLockedFrom(_from) isNotFrozenFrom(_from, _to) returns (bool) 
    {
        return super.transferFrom(_from, _to, _value);
    }

    function approve(address _spender, uint256 _value) public validateAddress(_spender) isNotFrozen(_spender) isNotTimeLocked() returns (bool) 
    {
        return super.approve(_spender, _value);
    }

    function increaseAllowance( address _spender, uint256 _addedValue ) public validateAddress(_spender) isNotFrozen(_spender) isNotTimeLocked() returns (bool)
    {
        return super.increaseAllowance(_spender, _addedValue);
    }

    function decreaseAllowance(address _spender, uint256 _subtractedValue) public validateAddress(_spender) isNotFrozen(_spender) isNotTimeLocked() returns (bool)
    {
        return super.decreaseAllowance(_spender, _subtractedValue);
    }


    /**
    * @dev Token Contract Emergency Drain
    * @param _token - Token to drain
    * @param _amount - Amount to drain
    */
    function emergencyERC20Drain( IERC20 _token, uint _amount ) public onlyOwner {
        _token.transfer( owner(), _amount );
    }
}