FSpot.MainWindow.HandleMergeTagsCommand C# (CSharp) Method

		public void HandleMergeTagsCommand (object obj, EventArgs args)
		{
			Tag[] tags = tag_selection_widget.TagHighlight;
			if (tags.Length < 2)
				return;

			// Translators, The singular case will never happen here.
			string header = Catalog.GetPluralString ("Merge the selected tag",
				                "Merge the {0} selected tags?", tags.Length);
			header = String.Format (header, tags.Length);

			// If a tag with children tags is selected for merging, we
			// should also merge its children..
			List<Tag> all_tags = new List<Tag> (tags.Length);
			foreach (Tag tag in tags) {
				if (!all_tags.Contains (tag))
					all_tags.Add (tag);
				else
					continue;

				if (!(tag is Category))
					continue;

				(tag as Category).AddDescendentsTo (all_tags);
			}

			// debug..
			tags = all_tags.ToArray ();
			System.Array.Sort (tags, new TagRemoveComparer ());

			foreach (Tag tag in tags) {
				Log.Debug ("tag: {0}", tag.Name);
			}

			string msg = Catalog.GetString ("This operation will merge the selected tags and any sub-tags into a single tag.");

			string ok_caption = Catalog.GetString ("_Merge Tags");

			if (ResponseType.Ok != HigMessageDialog.RunHigConfirmation (main_window,
				    DialogFlags.DestroyWithParent,
				    MessageType.Warning,
				    header,
				    msg,
				    ok_caption))
				return;

			// The surviving tag is the last tag, as it is definitely not a child of any other the
			// other tags.  removetags will contain the tags to be merged.
			Tag survivor = tags [tags.Length - 1];

			var removetags = new Tag [tags.Length - 1];
			Array.Copy (tags, 0, removetags, 0, tags.Length - 1);

			// Add the surviving tag to all the photos with the other tags
			var photos = Database.Photos.Query (removetags);
			foreach (Photo p in photos) {
				p.AddTag (survivor);
			}

			// Remove the defunct tags, which removes them from the photos, commits
			// the photos, and removes the tags from the TagStore
			Database.BeginTransaction ();
			Database.Photos.Remove (removetags);
			Database.CommitTransaction ();

			HandleEditSelectedTagWithTag (survivor);
		}