/*
 * Copyright (C) 2007 Eskil Bylund
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

using System;
using System.Collections.Generic;

using DCSharp.Backend.Managers;
using DCSharp.Backend.Objects;
using DCSharp.Xml;

namespace DCSharp
{
	// TODO: Get whether or not to monitor from the settings.
	/// <summary>
	/// Finds sources for the active downloads.
	/// </summary>
	public class FileFinder : IDisposable
	{
		private Runtime runtime;

		private ActionQueue<User> actionQueue;
		private bool monitorLists;
		private bool monitorResults;

		public FileFinder(Runtime runtime)
		{
			if (runtime == null)
			{
				throw new ArgumentNullException("runtime");
			}
			this.runtime = runtime;

			actionQueue = new ActionQueue<User>("FileFinderThread");

			runtime.DownloadManager.DownloaderAdded += OnDownloaderAdded;
			runtime.DownloadManager.DownloaderRemoved += OnDownloaderRemoved;
			runtime.SearchManager.ResultReceived += OnResultReceived;
		}

		#region Properties

		public bool MonitorFileLists
		{
			get { return monitorLists; }
			set { monitorLists = value; }
		}

		public bool MonitorSearchResults
		{
			get { return monitorResults; }
			set { monitorResults = value; }
		}

		#endregion

		#region Methods

		public void CheckFileList(User user)
		{
			ListDownloader downloader = runtime.DownloadManager.Find<ListDownloader>(
				delegate(ListDownloader ld)
			{
				return ld.User == user;
			});
			if (downloader == null && !actionQueue.Contains(user))
			{
				Monitor(runtime.DownloadManager.DownloadList(user));
			}
		}

		public void Dispose()
		{
			runtime.DownloadManager.DownloaderAdded -= OnDownloaderAdded;
			runtime.DownloadManager.DownloaderRemoved -= OnDownloaderRemoved;
			runtime.SearchManager.ResultReceived -= OnResultReceived;
		}

		#region Search

		private void OnResultReceived(object obj, ResultReceivedEventArgs args)
		{
			SearchResult result = args.Result;
			if (monitorResults && result.TTH != null)
			{
				FileDownloader downloader = runtime.DownloadManager.GetDownloader(result.TTH)
					as FileDownloader;
				if (downloader != null)
				{
					downloader.AddSource(result.User);
				}
			}
		}

		#endregion

		#region FileList

		private void Monitor(ListDownloader downloader)
		{
			downloader.ListReceived += OnListReceived;
		}

		private void OnDownloaderAdded(object obj, DownloadEventArgs args)
		{
			ListDownloader downloader = args.Downloader as ListDownloader;
			if (monitorLists && downloader != null)
			{
				Monitor(downloader);
			}
		}

		private void OnDownloaderRemoved(object obj, DownloadEventArgs args)
		{
			ListDownloader downloader = args.Downloader as ListDownloader;
			if (downloader != null)
			{
				downloader.ListReceived -= OnListReceived;
			}
		}

		private void OnListReceived(object obj, EventArgs args)
		{
			ListDownloader downloader = (ListDownloader)obj;
			if (downloader.Result != null)
			{
				actionQueue.Queue(downloader.User, FindSources, downloader);
			}
		}

		private void FindSources(object state)
		{
			ListDownloader downloader = (ListDownloader)state;
			FindSources(downloader.Result, downloader.User);
		}

		private void FindSources(FileList list, User user)
		{
			Queue<DirectoryNode> queue = new Queue<DirectoryNode>(list.Directories);
			while (queue.Count > 0)
			{
				DirectoryNode directory = queue.Dequeue();
				foreach (DirectoryNode child in directory.Directories)
				{
					queue.Enqueue(child);
				}
				foreach (FileNode file in directory.Files)
				{
					if (file.TTH != null)
					{
						FileDownloader downloader = runtime.DownloadManager.GetDownloader(file.TTH)
							as FileDownloader;
						if (downloader != null)
						{
							downloader.AddSource(user);
						}
					}
				}
			}
		}

		#endregion

		#endregion
	}
}