#ifndef __BlackList_C_
#define __BlackList_C_

#include "../misc_framework/DataNodes.h"


/* This file is responsible for blocking certain stocks at run time.
 *
 * We always start by loading all symbols we find in data/Symbols.txt.
 * BlackList allows us to remove some of those stocks while we are running.
 *
 * To black-list a stock, add the stock symbol to data/black-list.txt.
 * 
 * The idea is that you only add to this list over time.  In general,
 * if you remove a symbol, that will not un-black-list the symbol.
 * However, if you add a symbol then quickly remove it, there is no
 * guarantee that we even saw the change.  Just don't do that.
 *
 * The file should have one symbol per line.
 * The file can have Unix or DOS line endings.
 * The blank lines and blank spaces at the beginning or end of a line are 
 * ignored.
 * 
 * When we read the file we debounce any changes.  In case we are reading
 * while someone is writing.  So any time we see a change we wait 5 seconds
 * and take another look.  The file must stay the same for 5 seconds before
 * we actually use it.  Ideally you should always use mv to change a file
 * atomically.  However, I suspect this is being copied over using scp.
 * I would hate to black-list "A" and later realize I was supposed to
 * black-list "APPL"!
 *
 * This code rereads the file once per minute.
 *
 * This code sends a lot of details to the log file.  I'd hate to accidentally
 * turn off the wrong symbol, or ignore a valid request.  But if I do, I want
 * to know it!
 */

class BlackList : public DataNode
{
private:
  class FileWatcher : public DataNode
  {
  private:
    TimerThread::Helper _periodicTimer;
    TimerThread::Helper _singleTimer;
    std::string _body;
    std::set< std::string > _blackListed;
    bool _waitingForConfirmation;

    static std::string getFileContents();
    void addStrings();

    // From BroadcastMessageListener via DataNode
    virtual void onBroadcast(BroadcastMessage &message, int msgId);
    
    FileWatcher(DataNodeArgument const &args);
    friend class DataNode;

  public:

    bool isBlackListed(std::string const &symbol) const
    { return _blackListed.count(symbol); }
    
    static DataNodeLink *find(DataNodeListener *listener,
			      int msgId,
			      FileWatcher *&node);
  };
  
  const std::string _symbol;
  FileWatcher *_fileWatcher;

  bool _blackListed;
  
  // From DataNodeListener via DataNode
  virtual void onWakeup(int msgId);

  BlackList(DataNodeArgument const &args);
  friend class DataNode;

public:

  bool isBlackListed() const { return _blackListed; }

  static DataNodeLink *find(DataNodeListener *listener,
			    int msgId,
			    BlackList *&node,
			    std::string const &symbol);
  static DataNodeLink *find(BlackList *&node,
			    std::string const &symbol);
};


#endif