/*
 * This file Copyright (C) 2009-2015 Mnemosyne LLC
 *
 * It may be used under the GNU GPL versions 2 or 3
 * or any future license endorsed by Mnemosyne LLC.
 *
 */

#include <iostream>

#include <QDir>
#include <QFileSystemWatcher>
#include <QTimer>

#include <libtransmission/transmission.h>

#include "Prefs.h"
#include "TorrentModel.h"
#include "WatchDir.h"

/***
****
***/

WatchDir::WatchDir (const TorrentModel& model):
  myModel (model),
  myWatcher (0)
{
}

WatchDir::~WatchDir ()
{
}

/***
****
***/

int
WatchDir::metainfoTest (const QString& filename) const
{
  int ret;
  tr_info inf;
  tr_ctor * ctor = tr_ctorNew (0);

  // parse
  tr_ctorSetMetainfoFromFile (ctor, filename.toUtf8().constData());
  const int err = tr_torrentParse( ctor, &inf );
  if (err)
    ret = ERROR;
  else if (myModel.hasTorrent (QString::fromUtf8 (inf.hashString)))
    ret = DUPLICATE;
  else
    ret = OK;

  // cleanup
  if (!err)
    tr_metainfoFree (&inf);
  tr_ctorFree (ctor);
  return ret;
}

void
WatchDir::onTimeout ()
{
  QTimer * t = qobject_cast<QTimer*>(sender());
  const QString filename = t->objectName ();

  if (metainfoTest (filename) == OK)
    emit torrentFileAdded( filename );

  t->deleteLater( );
}

void
WatchDir::setPath (const QString& path, bool isEnabled)
{
  // clear out any remnants of the previous watcher, if any
  myWatchDirFiles.clear ();
  if (myWatcher)
    {
      delete myWatcher;
      myWatcher = 0;
    }

  // maybe create a new watcher
  if (isEnabled)
    {
      myWatcher = new QFileSystemWatcher ();
      myWatcher->addPath( path );
      connect (myWatcher, SIGNAL(directoryChanged(QString)),
               this, SLOT(watcherActivated(QString)));
      //std::cerr << "watching " << qPrintable(path) << " for new .torrent files" << std::endl;
      QTimer::singleShot (0, this, SLOT (rescanAllWatchedDirectories ())); // trigger the watchdir for .torrent files in there already
    }
}

void
WatchDir::watcherActivated (const QString& path)
{
  const QDir dir(path);

  // get the list of files currently in the watch directory
  QSet<QString> files;
  for (const QString& str: dir.entryList (QDir::Readable|QDir::Files))
    files.insert (str);

  // try to add any new files which end in .torrent
  const QSet<QString> newFiles (files - myWatchDirFiles);
  const QString torrentSuffix = QString::fromUtf8 (".torrent");
  for (const QString& name: newFiles)
    {
      if (name.endsWith (torrentSuffix, Qt::CaseInsensitive))
        {
          const QString filename = dir.absoluteFilePath (name);
          switch (metainfoTest (filename))
            {
              case OK:
                emit torrentFileAdded (filename);
                break;

              case DUPLICATE:
                break;

              case ERROR:
                {
                  // give the .torrent a few seconds to finish downloading
                  QTimer * t = new QTimer (this);
                  t->setObjectName (dir.absoluteFilePath (name));
                  t->setSingleShot (true);
                  connect( t, SIGNAL(timeout()), this, SLOT(onTimeout()));
                  t->start (5000);
                }
            }
        }
    }

  // update our file list so that we can use it
  // for comparison the next time around
  myWatchDirFiles = files;
}

void
WatchDir::rescanAllWatchedDirectories ()
{
  if (myWatcher == nullptr)
    return;

  for (const QString& path: myWatcher->directories ())
    watcherActivated (path);
}