pragma solidity ^0.4.24;


/**
 * @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 public 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;
  }

  /**
   * @dev Throws if called by any account other than the owner.
   */
  modifier onlyOwner() {
    require(msg.sender == owner);
    _;
  }

  /**
   * @dev Allows the current owner to relinquish control of the contract.
   */
  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;
  }
}


/**
 * @title KYC
 * @dev KYC contract handles the white list for PLCCrowdsale contract
 * Only accounts registered in KYC contract can buy PLC token.
 * Admins can register account, and the reason why
 */
contract KYC is Ownable {
  // check the address is registered for token sale
  mapping (address => bool) public registeredAddress;

  // check the address is admin of kyc contract
  mapping (address => bool) public admin;

  event Registered(address indexed _addr);
  event Unregistered(address indexed _addr);
  event SetAdmin(address indexed _addr, bool indexed _isAdmin);

  /**
   * @dev check whether the msg.sender is admin or not
   */
  modifier onlyAdmin() {
    require(admin[msg.sender]);
    _;
  }

  function KYC() public {
    admin[msg.sender] = true;
  }

  /**
   * @dev set new admin as admin of KYC contract
   * @param _addr address The address to set as admin of KYC contract
   */
  function setAdmin(address _addr, bool _isAdmin)
    public
    onlyOwner
  {
    require(_addr != address(0));
    admin[_addr] = _isAdmin;

    emit SetAdmin(_addr, _isAdmin);
  }

  /**
   * @dev register the address for token sale
   * @param _addr address The address to register for token sale
   */
  function register(address _addr)
    public
    onlyAdmin
  {
    require(_addr != address(0));

    registeredAddress[_addr] = true;

    emit Registered(_addr);
  }

  /**
   * @dev register the addresses for token sale
   * @param _addrs address[] The addresses to register for token sale
   */
  function registerByList(address[] _addrs)
    public
    onlyAdmin
  {
    for(uint256 i = 0; i < _addrs.length; i++) {
      require(_addrs[i] != address(0));

      registeredAddress[_addrs[i]] = true;

      emit Registered(_addrs[i]);
    }
  }

  /**
   * @dev unregister the registered address
   * @param _addr address The address to unregister for token sale
   */
  function unregister(address _addr)
    public
    onlyAdmin
  {
    registeredAddress[_addr] = false;

    emit Unregistered(_addr);
  }

  /**
   * @dev unregister the registered addresses
   * @param _addrs address[] The addresses to unregister for token sale
   */
  function unregisterByList(address[] _addrs)
    public
    onlyAdmin
  {
    for(uint256 i = 0; i < _addrs.length; i++) {
      registeredAddress[_addrs[i]] = false;

      emit Unregistered(_addrs[i]);
    }
  }
}