contract FBToken is AbstractToken {
  /**
   * Maximum allowed number of tokens in circulation.
   * tokenSupply = tokensIActuallyWant * (10 ^ decimals)
   */
   
   
  uint256 constant MAX_TOKEN_COUNT = 1000000000 * (10**18);
   
  /**
   * Address of the owner of this smart contract.
   */
  address private owner;
  
  /**
   * Frozen account list holder
   */
  mapping (address => bool) private frozenAccount;

  /**
   * Current number of tokens in circulation.
   */
  uint256 tokenCount = 0;
  
 
  /**
   * True if tokens transfers are currently frozen, false otherwise.
   */
  bool frozen = false;
  
 
  /**
   * Create new token smart contract and make msg.sender the
   * owner of this smart contract.
   */
  function FBToken () {
    owner = msg.sender;
  }

  /**
   * Get total number of tokens in circulation.
   *
   * @return total number of tokens in circulation
   */
  function totalSupply() constant returns (uint256 supply) {
    return tokenCount;
  }

  string constant public name = "Facebucks";
  string constant public symbol = "FB";
  uint8 constant public decimals = 18;
  
  /**
   * Transfer given number of tokens from message sender to given recipient.
   * @param _to address to transfer tokens to the owner of
   * @param _value number of tokens to transfer to the owner of given address
   * @return true if tokens were transferred successfully, false otherwise
   */
  function transfer(address _to, uint256 _value) returns (bool success) {
    require(!frozenAccount[msg.sender]);
	if (frozen) return false;
    else return AbstractToken.transfer (_to, _value);
  }

  /**
   * Transfer given number of tokens from given owner to given recipient.
   *
   * @param _from address to transfer tokens from the owner of
   * @param _to address to transfer tokens to the owner of
   * @param _value number of tokens to transfer from given owner to given
   *        recipient
   * @return true if tokens were transferred successfully, false otherwise
   */
  function transferFrom(address _from, address _to, uint256 _value)
    returns (bool success) {
	require(!frozenAccount[_from]);
    if (frozen) return false;
    else return AbstractToken.transferFrom (_from, _to, _value);
  }

   /**
   * Change how many tokens given spender is allowed to transfer from message
   * spender.  In order to prevent double spending of allowance,
   * 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
   * @param _spender address to allow the owner of to transfer tokens from
   *        message sender
   * @param _value number of tokens to allow to transfer
   * @return true if token transfer was successfully approved, false otherwise
   */
  function approve (address _spender, uint256 _value)
    returns (bool success) {
	require(allowance (msg.sender, _spender) == 0 || _value == 0);
    return AbstractToken.approve (_spender, _value);
  }

  /**
   * Create _value new tokens and give new created tokens to msg.sender.
   * May only be called by smart contract owner.
   *
   * @param _value number of tokens to create
   * @return true if tokens were created successfully, false otherwise
   */
  function createTokens(uint256 _value)
    returns (bool success) {
    require (msg.sender == owner);

    if (_value > 0) {
      if (_value > safeSub (MAX_TOKEN_COUNT, tokenCount)) return false;
	  
      accounts [msg.sender] = safeAdd (accounts [msg.sender], _value);
      tokenCount = safeAdd (tokenCount, _value);
	  
	  // adding transfer event and _from address as null address
	  emit Transfer(0x0, msg.sender, _value);
	  
	  return true;
    }
	
	  return false;
    
  }
  

  /**
   * Set new owner for the smart contract.
   * May only be called by smart contract owner.
   *
   * @param _newOwner address of new owner of the smart contract
   */
  function setOwner(address _newOwner) {
    require (msg.sender == owner);

    owner = _newOwner;
  }

  /**
   * Freeze ALL token transfers.
   * May only be called by smart contract owner.
   */
  function freezeTransfers () {
    require (msg.sender == owner);

    if (!frozen) {
      frozen = true;
      emit Freeze ();
    }
  }

  /**
   * Unfreeze ALL token transfers.
   * May only be called by smart contract owner.
   */
  function unfreezeTransfers () {
    require (msg.sender == owner);

    if (frozen) {
      frozen = false;
      emit Unfreeze ();
    }
  }
  
  
  /*A user is able to unintentionally send tokens to a contract 
  * and if the contract is not prepared to refund them they will get stuck in the contract. 
  * The same issue used to happen for Ether too but new Solidity versions added the payable modifier to
  * prevent unintended Ether transfers. However, there’s no such mechanism for token transfers.
  * so the below function is created
  */
  
  function refundTokens(address _token, address _refund, uint256 _value) {
    require (msg.sender == owner);
    require(_token != address(this));
    AbstractToken token = AbstractToken(_token);
    token.transfer(_refund, _value);
    emit RefundTokens(_token, _refund, _value);
  }
  
  /**
   * Freeze specific account
   * May only be called by smart contract owner.
   */
  function freezeAccount(address _target, bool freeze) {
      require (msg.sender == owner);
	  require (msg.sender != _target);
      frozenAccount[_target] = freeze;
      emit FrozenFunds(_target, freeze);
 }

  /**
   * Logged when token transfers were frozen.
   */
  event Freeze ();

  /**
   * Logged when token transfers were unfrozen.
   */
  event Unfreeze ();
  
  /**
   * Logged when a particular account is frozen.
   */
  
  event FrozenFunds(address target, bool frozen);


  
  /**
   * when accidentally send other tokens are refunded
   */
  
  event RefundTokens(address _token, address _refund, uint256 _value);
}
/**
 * Facebucks smart contract.
 */
function totalSupply() constant returns (uint256 supply) {
    return tokenCount;
  }
/**
 * Get total number of tokens in circulation.
 *
 * @return total number of tokens in circulation
 */