h1. Managing Torrents

[[Managing Torrents#Example-1|Example 1]] shows how to add a torrent to the engine and start the download
[[Managing Torrents#Example-2|Example 2]] shows how to hash check a torrent and show a progress indicator
[[Managing Torrents#Example-3|Example 3]] shows how to stop a torrent and remove it from the engine

h2. Example 1

<pre><code class="java">
    class MainClass
    {
        ClientEngine engine;
        string savePath;

        // savePath is the directory where downloads will be stored
        public MainClass(string savePath)
        {
            // Create a basic ClientEngine without changing any settings
            this.engine = new ClientEngine(new EngineSettings());
            this.savePath = savePath;
        }

        public void DownloadTorrent(string path)
        {
            // Open the .torrent file
            Torrent torrent = Torrent.Load(path);

            // Create the manager which will download the torrent to savePath
            // using the default settings.
            TorrentManager manager = new TorrentManager(torrent, savePath, new TorrentSettings());

            // Register the manager with the engine
            engine.Register(manager);

            // Begin the download. It is not necessary to call HashCheck on the manager
            // before starting the download. If a hash check has not been performed, the
            // manager will enter the Hashing state and perform a hash check before it
            // begins downloading.

            // If the torrent is fully downloaded already, calling 'Start' will place
            // the manager in the Seeding state.
            manager.Start();
        }
    }
</code></pre>

h2. Example 2

<pre><code class="java">
        public void HashTorrent(TorrentManager manager)
        {
            // Note: The manager must be in the 'Stopped' state in order to perform
            // a hash check. Also, to make the sample easier the event handler
            // is not unregistered. In your application be careful you don't
            // accidentally attach a new event handler every time the torrent is hashed
            manager.PieceHashed += delegate (object o, PieceHashedEventArgs e) {
                int pieceIndex = e.PieceIndex;
                int totalPieces = e.TorrentManager.Torrent.Pieces.Count;
                double progress = (double) pieceIndex / totalPieces * 100.0;
                if (e.HashPassed)
                    Console.WriteLine("Piece {0} of {1} is complete", pieceIndex, totalPieces);
                else
                    Console.WriteLine("Piece {0} of {1} is corrupt or incomplete ", pieceIndex, totalPieces);
                
                // This shows how complete the hashing is.
                Console.WriteLine("Total progress is: {0}%", progress);

                // This shows the percentage completion of the download. This value
                // is updated as the torrent is hashed or new pieces are downloaded
                Console.WriteLine("{0}% of the torrent is complete");
            };

            // If 'true' is passed, the torrent will automatically go to the 'Downloading' or 'Seeding'
            // state once the hash check is finished. Otherwise it will return to the 'Stopped' state.
            manager.HashCheck(false);
        }
</code></pre>


h2. Example 3

<pre><code class="java">
        public void StopTorrent(TorrentManager manager)
        {
            // When stopping a torrent, certain cleanup tasks need to be perfomed
            // such as flushing unwritten data to disk and informing the tracker
            // the client is no longer downloading/seeding the torrent. To allow for
            // this, when Stop is called the manager enters a 'Stopping' state. Once
            // all the tasks are completed the manager will enter the 'Stopped' state.

            // Hook into the TorrentStateChanged event so we can tell when the torrent
            // finishes cleanup
            manager.TorrentStateChanged += delegate (object o, TorrentStateChangedEventArgs e) {
                if (e.NewState == TorrentState.Stopping)
                {
                    Console.WriteLine("Torrent {0} has begun stopping", e.TorrentManager.Torrent.Name);
                }
                else if (e.NewState == TorrentState.Stopped)
                {
                    // It is now safe to unregister the torrent from the engine and dispose of it (if required)
                    engine.Unregister(manager);
                    manager.Dispose();

                    Console.WriteLine("Torrent {0} has stopped", e.TorrentManager.Torrent.Name);
                }
            };

            // Begin the process to stop the torrent
            manager.Stop ();
        }
</code></pre>