pragma solidity ^0.4.13;


/**
 * @title SafeMath
 * @dev Math operations with safety checks that throw on error
 */
contract SafeMath {
  function mul(uint256 a, uint256 b) internal constant returns (uint256) {
    uint256 c = a * b;
    assert(a == 0 || c / a == b);
    return c;
  }

  function div(uint256 a, uint256 b) internal constant 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 c;
  }

  function sub(uint256 a, uint256 b) internal constant returns (uint256) {
    assert(b <= a);
    return a - b;
  }

  function add(uint256 a, uint256 b) internal constant returns (uint256) {
    uint256 c = a + b;
    assert(c >= a);
    return c;
  }

  function max64(uint64 a, uint64 b) internal constant returns (uint64) {
    return a >= b ? a : b;
  }

  function min64(uint64 a, uint64 b) internal constant returns (uint64) {
    return a < b ? a : b;
  }

  function max256(uint256 a, uint256 b) internal constant returns (uint256) {
    return a >= b ? a : b;
  }

  function min256(uint256 a, uint256 b) internal constant returns (uint256) {
    return a < b ? a : b;
  }
}


/**
 * @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;


  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */
  function Ownable() {
    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 transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function transferOwnership(address newOwner) onlyOwner {
    require(newOwner != address(0));
    owner = newOwner;
  }

}

/**
 * @title ERC20Basic
 * @dev Simpler version of ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/179
 */
contract ERC20Basic {
  uint256 public totalSupply;
  function balanceOf(address who) constant returns (uint256);
  function transfer(address to, uint256 value) 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) constant returns (uint256);
  function transferFrom(address from, address to, uint256 value) returns (bool);
  function approve(address spender, uint256 value) returns (bool);
  event Approval(address indexed owner, address indexed spender, uint256 value);
}


/**
 * @title Basic token
 * @dev Basic version of StandardToken, with no allowances.
 */
contract BasicToken is SafeMath, ERC20Basic {

  mapping(address => uint256) balances;

  /**
   * @dev Fix for the ERC20 short address attack.
   */
  modifier onlyPayloadSize(uint size) {
    require(msg.data.length >= size + 4);
     _;
  }

  /**
  * @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) onlyPayloadSize(2 * 32) returns (bool){
    balances[msg.sender] = sub(balances[msg.sender],_value);
    balances[_to] = add(balances[_to],_value);
    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 uint representing the amount owned by the passed address.
  */
  function balanceOf(address _owner) constant returns (uint balance) {
    return balances[_owner];
  }

}



/**
 * @title Standard ERC20 token
 *
 * @dev Implementation of the basic standard token.
 * @dev https://github.com/ethereum/EIPs/issues/20
 * @dev 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)) 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 amout of tokens to be transfered
   */
  function transferFrom(address _from, address _to, uint256 _value) onlyPayloadSize(2 * 32) returns (bool) {
    var _allowance = allowed[_from][msg.sender];

    // Check is not needed because sub(_allowance, _value) will already throw if this condition is not met
    // require (_value <= _allowance);

    balances[_to] = add(balances[_to],_value);
    balances[_from] = sub(balances[_from],_value);
    allowed[_from][msg.sender] = sub(_allowance,_value);
    Transfer(_from, _to, _value);
    return true;
  }

  /**
   * @dev Aprove the passed address to spend the specified amount of tokens on behalf of msg.sender.
   * @param _spender The address which will spend the funds.
   * @param _value The amount of tokens to be spent.
   */
  function approve(address _spender, uint256 _value) returns (bool) {

    // To change the approve amount you first have to reduce the addresses`
    //  allowance to zero by calling `approve(_spender, 0)` if it is not
    //  already 0 to mitigate the race condition described here:
    //  https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
    require((_value == 0) || (allowed[msg.sender][_spender] == 0));

    allowed[msg.sender][_spender] = _value;
    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 specifing the amount of tokens still available for the spender.
   */
  function allowance(address _owner, address _spender) constant returns (uint256 remaining) {
    return allowed[_owner][_spender];
  }

}






/**
 * @title Pausable
 * @dev Base contract which allows children to implement an emergency stop mechanism.
 */
contract Pausable is Ownable {
  event Pause();
  event Unpause();

  bool public paused = false;


  /**
   * @dev modifier to allow actions only when the contract IS paused
   */
  modifier whenNotPaused() {
    require(!paused);
    _;
  }

  /**
   * @dev modifier to allow actions only when the contract IS NOT paused
   */
  modifier whenPaused() {
    require(paused);
    _;
  }

  /**
   * @dev called by the owner to pause, triggers stopped state
   */
  function pause() onlyOwner whenNotPaused {
    paused = true;
    Pause();
  }

  /**
   * @dev called by the owner to unpause, returns to normal state
   */
  function unpause() onlyOwner whenPaused {
    paused = false;
    Unpause();
  }
}



/**
 * Pausable token
 *
 * Simple ERC20 Token example, with pausable token creation
 **/

contract PausableToken is StandardToken, Pausable {

  function transfer(address _to, uint256 _value) whenNotPaused returns (bool) {
    return super.transfer(_to, _value);
  }

  function transferFrom(address _from, address _to, uint256 _value) whenNotPaused returns (bool) {
    return super.transferFrom(_from, _to, _value);
  }
}


/**
 * @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, SafeMath, Pausable {
  // 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 NewAdmin(address indexed _addr);

  /**
   * @dev check whether the address is registered for token sale or not.
   * @param _addr address
   */
  modifier onlyRegistered(address _addr) {
    require(isRegistered(_addr));
    _;
  }

  /**
   * @dev check whether the msg.sender is admin or not
   */
  modifier onlyAdmin() {
    require(admin[msg.sender]);
    _;
  }

  function KYC() {
    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)
    public
    onlyOwner
  {
    require(_addr != address(0) && admin[_addr] == false);
    admin[_addr] = true;

    NewAdmin(_addr);
  }

  /**
   * @dev check the address is register for token sale
   * @param _addr address The address to check whether register or not
   */
  function isRegistered(address _addr)
    public
    constant
    returns (bool)
  {
    return registeredAddress[_addr];
  }

  /**
   * @dev register the address for token sale
   * @param _addr address The address to register for token sale
   */
  function register(address _addr)
    public
    onlyAdmin
    whenNotPaused
  {
    require(_addr != address(0) && registeredAddress[_addr] == false);

    registeredAddress[_addr] = true;

    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
    whenNotPaused
  {
    for(uint256 i = 0; i < _addrs.length; i++) {
      require(_addrs[i] != address(0) && registeredAddress[_addrs[i]] == false);

      registeredAddress[_addrs[i]] = true;

      Registered(_addrs[i]);
    }
  }

  /**
   * @dev unregister the registered address
   * @param _addr address The address to unregister for token sale
   */
  function unregister(address _addr)
    public
    onlyAdmin
    onlyRegistered(_addr)
  {
    registeredAddress[_addr] = false;

    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++) {
      require(isRegistered(_addrs[i]));

      registeredAddress[_addrs[i]] = false;

      Unregistered(_addrs[i]);
    }

  }
}