//
// Copyright (C) 2009 Jordi Mas i Hernandez, jmas@softcatala.org
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

using System;
using System.IO;
using System.Runtime.InteropServices;
using Gdk;

using Mistelix.Core;

namespace Mistelix.Backends.ThumbnailCache
{
	//
	// This class uses Gnome-desktop thumbnailing infrastructure for loading and storing thumbnails
	// It allows to reuse the thumbnails created already by Nautilus and other GNOME applications
	// 
	// See: http://library.gnome.org/devel/gnome-desktop/stable/
	// 
	public class Gnome : Provider
	{
		[DllImport ("libgnome-desktop-2")]
		static extern IntPtr gnome_desktop_thumbnail_factory_new (int size);

		[DllImport ("libgnome-desktop-2")] // returns GdkPixbuf * 
		static extern IntPtr gnome_desktop_thumbnail_factory_generate_thumbnail (IntPtr factory, string uri, string mime_type);

		[DllImport ("libgnome-desktop-2")]
		static extern void gnome_desktop_thumbnail_factory_save_thumbnail (IntPtr factory, IntPtr thumbnail, string uri, ulong time);

		[DllImport ("libgnome-desktop-2")]
		static extern IntPtr gnome_desktop_thumbnail_factory_lookup (IntPtr factory, string uri, ulong time);

	        [DllImport("libglib-2.0")]
		static extern IntPtr g_filename_to_uri (IntPtr filename, IntPtr hostname, IntPtr error);

		[DllImport("libgio-2.0")]
		static extern IntPtr g_content_type_guess (IntPtr filename, out byte data, UIntPtr data_size, out bool result_uncertain);

		[DllImport ("libgio-2.0")]
		static extern IntPtr g_file_new_for_uri (string uri);

		[DllImport ("libgio-2.0")]
		static extern ulong g_file_info_get_attribute_uint64 (IntPtr file, string attribute);

		[DllImport("libgio-2.0")] // returns GFileInfo *
		static extern  IntPtr g_file_query_info (IntPtr gfile, string attributes, int flags, IntPtr cancellable, out IntPtr error);

		[DllImport("libgio-2.0")]
		static extern void g_file_info_get_modification_time (IntPtr raw, IntPtr result);

		[DllImport("libgobject-2.0")]
		static extern void g_object_unref (IntPtr raw);

		IntPtr factory_normal;
		IntPtr factory_large;

		const int GNOME_DESKTOP_THUMBNAIL_SIZE_NORMAL = 0;
		const int GNOME_DESKTOP_THUMBNAIL_SIZE_LARGE = 1;
	
		public Gnome ()
		{
			try {
				GLib.GType.Init (); // The following calls assume that Glib is initialized
				factory_normal = gnome_desktop_thumbnail_factory_new (GNOME_DESKTOP_THUMBNAIL_SIZE_NORMAL);
				factory_large = gnome_desktop_thumbnail_factory_new (GNOME_DESKTOP_THUMBNAIL_SIZE_LARGE);
			}
			catch (Exception e) {
				Logger.Error ("Gnome.Gnome. Unhandled exception {0}", e);
			}
		}

		public override bool Installed {
			get {
				return (factory_normal != IntPtr.Zero);
			}
		}

		public override Gdk.Pixbuf GetThumbnail (string filename, int width, int height)
		{
			try {
				IntPtr pix_raw, path_raw, uri_raw, mime_raw, factory_raw, thumbnail_raw;
				string uri, mime_type, thumbnail_file;
				byte data;
				ulong data_size = 0, time;
				bool result_uncertain;
				Pixbuf pix;

				path_raw = GLib.Marshaller.StringToPtrGStrdup (filename);
				if (path_raw == IntPtr.Zero)
					return null;

				// Get URI
				uri_raw = g_filename_to_uri (path_raw, IntPtr.Zero, IntPtr.Zero);
				uri = GLib.Marshaller.Utf8PtrToString (uri_raw);

				factory_raw = (width > 128 || height > 128) ? factory_large : factory_normal;

				time = GetTimeModified (uri);

				if (time == 0)
					return null;

				// Verifies that the thumbnail exists and it is updated
				thumbnail_raw = gnome_desktop_thumbnail_factory_lookup (factory_raw, uri, time);
				thumbnail_file = GLib.Marshaller.Utf8PtrToString (thumbnail_raw);
				GLib.Marshaller.Free (thumbnail_raw);

				// Does thumbnail file exists already?
				if (String.IsNullOrEmpty (thumbnail_file) == false) {
					Logger.Debug ("Gnome.GetThumbnail. Cached image found {0}", thumbnail_file);
					GLib.Marshaller.Free (uri_raw);
					GLib.Marshaller.Free (path_raw);
					return new Pixbuf (thumbnail_file);
				}

				// Get MimeType
				mime_raw = g_content_type_guess (path_raw, out data, new UIntPtr (data_size), out result_uncertain);
				mime_type = GLib.Marshaller.PtrToStringGFree (mime_raw);
				pix_raw = gnome_desktop_thumbnail_factory_generate_thumbnail (factory_raw, uri, mime_type);

				GLib.Marshaller.Free (uri_raw);
				GLib.Marshaller.Free (path_raw);

				pix = new Gdk.Pixbuf (pix_raw);
				StoreThumbnail (uri,  pix);
				return pix;
			} 
			catch (Exception e) {
				Logger.Error ("Gnome.GetThumbnail. Error {0}", e);
				return null;
			}
		}

		public override void StoreThumbnail (string uri, Gdk.Pixbuf pixbuf)
		{
			IntPtr factory_raw;
			ulong time;

			try 
			{
				time = GetTimeModified (uri);
				if (time == 0)
					return;

				factory_raw = (pixbuf.Width > 128 || pixbuf.Height > 128) ? factory_large : factory_normal;
				gnome_desktop_thumbnail_factory_save_thumbnail (factory_raw, pixbuf.Handle, uri, time);
				Logger.Debug ("Gnome.StoreThumbnail. Cached image {0}", uri);
			}

			catch (Exception e) {
				Logger.Error ("Gnome.StoreThumbnail. Error {0}", e);
				return;
			}
		}

		ulong GetTimeModified (string uri)
		{
			ulong time;
			IntPtr file_raw, fileinfo_raw, error_raw;
	
			file_raw  = g_file_new_for_uri (uri);
			fileinfo_raw =  g_file_query_info (file_raw, "time::modified", 0, IntPtr.Zero, out error_raw);
			g_object_unref (file_raw);

			if (fileinfo_raw == IntPtr.Zero) // File not found for example
				return 0;

			time = g_file_info_get_attribute_uint64 (fileinfo_raw, "time::modified");
			return time;
		}
	}
}