/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 8; tab-width: 8 -*-

   nemo-desktop-directory.c: Subclass of NemoDirectory to implement
   a virtual directory consisting of the desktop directory and the desktop
   icons
 
   Copyright (C) 2003 Red Hat, Inc.
  
   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 Street - Suite 500,
   Boston, MA 02110-1335, USA.
  
   Author: Alexander Larsson <alexl@redhat.com>
*/

#include <config.h>
#include "nemo-desktop-directory.h"

#include "nemo-directory-private.h"
#include "nemo-file.h"
#include "nemo-file-private.h"
#include "nemo-file-utilities.h"
#include "nemo-global-preferences.h"
#include <gtk/gtk.h>

struct NemoDesktopDirectoryDetails {
	NemoDirectory *real_directory;
	GHashTable *callbacks;
	GHashTable *monitors;
};

typedef struct {
	NemoDesktopDirectory *desktop_dir;
	NemoDirectoryCallback callback;
	gpointer callback_data;

	NemoFileAttributes wait_for_attributes;
	gboolean wait_for_file_list;

	GList *non_ready_directories;
	GList *merged_file_list;
} MergedCallback;


typedef struct {
	NemoDesktopDirectory *desktop_dir;

	gboolean monitor_hidden_files;
	NemoFileAttributes monitor_attributes;
} MergedMonitor;

static void desktop_directory_changed_callback (gpointer data);

G_DEFINE_TYPE (NemoDesktopDirectory, nemo_desktop_directory,
	       NEMO_TYPE_DIRECTORY);

static gboolean
desktop_contains_file (NemoDirectory *directory,
		       NemoFile *file)
{
	NemoDesktopDirectory *desktop;

	desktop = NEMO_DESKTOP_DIRECTORY (directory);

	if (nemo_directory_contains_file (desktop->details->real_directory, file)) {
		return TRUE;
	}

	return file->details->directory == directory;
}

static guint
merged_callback_hash (gconstpointer merged_callback_as_pointer)
{
	const MergedCallback *merged_callback;

	merged_callback = merged_callback_as_pointer;
	return GPOINTER_TO_UINT (merged_callback->callback)
		^ GPOINTER_TO_UINT (merged_callback->callback_data);
}

static gboolean
merged_callback_equal (gconstpointer merged_callback_as_pointer,
		       gconstpointer merged_callback_as_pointer_2)
{
	const MergedCallback *merged_callback, *merged_callback_2;

	merged_callback = merged_callback_as_pointer;
	merged_callback_2 = merged_callback_as_pointer_2;

	return merged_callback->callback == merged_callback_2->callback
		&& merged_callback->callback_data == merged_callback_2->callback_data;
}

static void
merged_callback_destroy (MergedCallback *merged_callback)
{
	g_assert (merged_callback != NULL);
	g_assert (NEMO_IS_DESKTOP_DIRECTORY (merged_callback->desktop_dir));

	g_list_free (merged_callback->non_ready_directories);
	nemo_file_list_free (merged_callback->merged_file_list);
	g_free (merged_callback);
}

static void
merged_callback_check_done (MergedCallback *merged_callback)
{
	/* Check if we are ready. */
	if (merged_callback->non_ready_directories != NULL) {
		return;
	}

	/* Remove from the hash table before sending it. */
	g_hash_table_steal (merged_callback->desktop_dir->details->callbacks, merged_callback);

	/* We are ready, so do the real callback. */
	(* merged_callback->callback) (NEMO_DIRECTORY (merged_callback->desktop_dir),
				       merged_callback->merged_file_list,
				       merged_callback->callback_data);

	/* And we are done. */
	merged_callback_destroy (merged_callback);
}

static void
merged_callback_remove_directory (MergedCallback *merged_callback,
				  NemoDirectory *directory)
{
	merged_callback->non_ready_directories = g_list_remove
		(merged_callback->non_ready_directories, directory);
	merged_callback_check_done (merged_callback);
}

static void
directory_ready_callback (NemoDirectory *directory,
			  GList *files,
			  gpointer callback_data)
{
	MergedCallback *merged_callback;

	g_assert (NEMO_IS_DIRECTORY (directory));
	g_assert (callback_data != NULL);

	merged_callback = callback_data;
	g_assert (g_list_find (merged_callback->non_ready_directories, directory) != NULL);

	/* Update based on this call. */
	merged_callback->merged_file_list = g_list_concat
		(merged_callback->merged_file_list,
		 nemo_file_list_copy (files));

	/* Check if we are ready. */
	merged_callback_remove_directory (merged_callback, directory);
}

static void
desktop_call_when_ready (NemoDirectory *directory,
			 NemoFileAttributes file_attributes,
			 gboolean wait_for_file_list,
			 NemoDirectoryCallback callback,
			 gpointer callback_data)
{
	NemoDesktopDirectory *desktop;
	MergedCallback search_key, *merged_callback;

	desktop = NEMO_DESKTOP_DIRECTORY (directory);

	/* Check to be sure we aren't overwriting. */
	search_key.callback = callback;
	search_key.callback_data = callback_data;
	if (g_hash_table_lookup (desktop->details->callbacks, &search_key) != NULL) {
		g_warning ("tried to add a new callback while an old one was pending");
		return;
	}

	/* Create a merged_callback record. */
	merged_callback = g_new0 (MergedCallback, 1);
	merged_callback->desktop_dir = desktop;
	merged_callback->callback = callback;
	merged_callback->callback_data = callback_data;
	merged_callback->wait_for_attributes = file_attributes;
	merged_callback->wait_for_file_list = wait_for_file_list;
	merged_callback->non_ready_directories = g_list_prepend
			(merged_callback->non_ready_directories, directory);
	merged_callback->non_ready_directories = g_list_prepend
			(merged_callback->non_ready_directories, desktop->details->real_directory);


	merged_callback->merged_file_list = g_list_concat (NULL,
							   nemo_file_list_copy (directory->details->file_list));

	/* Put it in the hash table. */
	g_hash_table_insert (desktop->details->callbacks,
			     merged_callback, merged_callback);

	/* Now tell all the directories about it. */
	nemo_directory_call_when_ready
		(desktop->details->real_directory,
		 merged_callback->wait_for_attributes,
		 merged_callback->wait_for_file_list,
		 directory_ready_callback, merged_callback);
	nemo_directory_call_when_ready_internal
		(directory,
		 NULL,
		 merged_callback->wait_for_attributes,
		 merged_callback->wait_for_file_list,
		 directory_ready_callback,
		 NULL,
		 merged_callback);
	
}

static void
desktop_cancel_callback (NemoDirectory *directory,
			NemoDirectoryCallback callback,
			gpointer callback_data)
{
	NemoDesktopDirectory *desktop;
	MergedCallback search_key, *merged_callback;
	GList *node;

	desktop = NEMO_DESKTOP_DIRECTORY (directory);

	/* Find the entry in the table. */
	search_key.callback = callback;
	search_key.callback_data = callback_data;
	merged_callback = g_hash_table_lookup (desktop->details->callbacks, &search_key);
	if (merged_callback == NULL) {
		return;
	}

	/* Remove from the hash table before working with it. */
	g_hash_table_steal (merged_callback->desktop_dir->details->callbacks, merged_callback);

	/* Tell all the directories to cancel the call. */
	for (node = merged_callback->non_ready_directories; node != NULL; node = node->next) {
		nemo_directory_cancel_callback
			(node->data,
			 directory_ready_callback, merged_callback);
	}
	merged_callback_destroy (merged_callback);
}

static void
merged_monitor_destroy (MergedMonitor *monitor)
{
	NemoDesktopDirectory *desktop;

	desktop = monitor->desktop_dir;
	
	/* Call through to the real directory remove calls. */
	nemo_directory_file_monitor_remove (desktop->details->real_directory, monitor);

	nemo_directory_monitor_remove_internal (NEMO_DIRECTORY (desktop), NULL, monitor);
	
	g_free (monitor);
}

static void
build_merged_callback_list (NemoDirectory *directory,
			    GList *file_list,
			    gpointer callback_data)
{
	GList **merged_list;

	merged_list = callback_data;
	*merged_list = g_list_concat (*merged_list,
				      nemo_file_list_copy (file_list));
}

static void
desktop_monitor_add (NemoDirectory *directory,
		    gconstpointer client,
		    gboolean monitor_hidden_files,
		    NemoFileAttributes file_attributes,
		    NemoDirectoryCallback callback,
		    gpointer callback_data)
{
	NemoDesktopDirectory *desktop;
	MergedMonitor *monitor;
	GList *merged_callback_list;

	desktop = NEMO_DESKTOP_DIRECTORY (directory);

	/* Map the client to a unique value so this doesn't interfere
	 * with direct monitoring of the directory by the same client.
	 */
	monitor = g_hash_table_lookup (desktop->details->monitors, client);
	if (monitor != NULL) {
		g_assert (monitor->desktop_dir == desktop);
	} else {
		monitor = g_new0 (MergedMonitor, 1);
		monitor->desktop_dir = desktop;
		g_hash_table_insert (desktop->details->monitors,
				     (gpointer) client, monitor);
	}
	monitor->monitor_hidden_files = monitor_hidden_files;
	monitor->monitor_attributes = file_attributes;
	
	/* Call through to the real directory add calls. */
	merged_callback_list = NULL;

	/* Call up to real dir */
	nemo_directory_file_monitor_add
		(desktop->details->real_directory, monitor,
		 monitor_hidden_files,
		 file_attributes,
		 build_merged_callback_list, &merged_callback_list);
	
	/* Handle the desktop part */
	merged_callback_list = g_list_concat (merged_callback_list,
					      nemo_file_list_copy (directory->details->file_list));

	
	if (callback != NULL) {
		(* callback) (directory, merged_callback_list, callback_data);
	}
	nemo_file_list_free (merged_callback_list);
}

static void
desktop_monitor_remove (NemoDirectory *directory,
		       gconstpointer client)
{
	NemoDesktopDirectory *desktop;
	MergedMonitor *monitor;
	
	desktop = NEMO_DESKTOP_DIRECTORY (directory);

	monitor = g_hash_table_lookup (desktop->details->monitors, client);
	if (monitor == NULL) {
		return;
	}
	
	g_hash_table_remove (desktop->details->monitors, client);
}

static void
desktop_force_reload (NemoDirectory *directory)
{
	NemoDesktopDirectory *desktop;

	desktop = NEMO_DESKTOP_DIRECTORY (directory);

	nemo_directory_force_reload (desktop->details->real_directory);

	/* We don't invalidate the files in desktop, since they are always
	   up to date. (And we don't ever want to mark them invalid.) */
}

static gboolean
desktop_are_all_files_seen (NemoDirectory *directory)
{
	NemoDesktopDirectory *desktop;

	desktop = NEMO_DESKTOP_DIRECTORY (directory);

	if (!nemo_directory_are_all_files_seen (desktop->details->real_directory)) {
		return FALSE;
	}

	return TRUE;
}

static gboolean
desktop_is_not_empty (NemoDirectory *directory)
{
	NemoDesktopDirectory *desktop;

	desktop = NEMO_DESKTOP_DIRECTORY (directory);

	if (nemo_directory_is_not_empty (desktop->details->real_directory)) {
		return TRUE;
	}

	return directory->details->file_list != NULL;
}

static GList *
desktop_get_file_list (NemoDirectory *directory)
{
	GList *real_dir_file_list, *desktop_dir_file_list = NULL;
	
	real_dir_file_list = nemo_directory_get_file_list
				(NEMO_DESKTOP_DIRECTORY (directory)->details->real_directory);
	desktop_dir_file_list = NEMO_DIRECTORY_CLASS (nemo_desktop_directory_parent_class)->get_file_list (directory);

	return g_list_concat (real_dir_file_list, desktop_dir_file_list);
}

NemoDirectory *
nemo_desktop_directory_get_real_directory (NemoDesktopDirectory *desktop)
{
	nemo_directory_ref (desktop->details->real_directory);
	return desktop->details->real_directory;
}


static void
desktop_finalize (GObject *object)
{
	NemoDesktopDirectory *desktop;

	desktop = NEMO_DESKTOP_DIRECTORY (object);

	nemo_directory_unref (desktop->details->real_directory);

	g_hash_table_destroy (desktop->details->callbacks);
	g_hash_table_destroy (desktop->details->monitors);
	g_free (desktop->details);

	g_signal_handlers_disconnect_by_func (nemo_preferences,
					      desktop_directory_changed_callback,
					      desktop);

	G_OBJECT_CLASS (nemo_desktop_directory_parent_class)->finalize (object);
}

static void
done_loading_callback (NemoDirectory *real_directory,
		       NemoDesktopDirectory *desktop)
{
     nemo_directory_emit_done_loading (NEMO_DIRECTORY (desktop));
}


static void
forward_files_added_cover (NemoDirectory *real_directory,
			   GList *files,
			   gpointer callback_data)
{
	nemo_directory_emit_files_added (NEMO_DIRECTORY (callback_data), files);
}

static void
forward_files_changed_cover (NemoDirectory *real_directory,
			     GList *files,
			     gpointer callback_data)
{
	nemo_directory_emit_files_changed (NEMO_DIRECTORY (callback_data), files);
}

static void
update_desktop_directory (NemoDesktopDirectory *desktop)
{
	char *desktop_path;
	char *desktop_uri;
	NemoDirectory *real_directory;

	real_directory = desktop->details->real_directory;
	if (real_directory != NULL) {
		g_hash_table_remove_all (desktop->details->callbacks);
		g_hash_table_remove_all (desktop->details->monitors);

		g_signal_handlers_disconnect_by_func (real_directory, done_loading_callback, desktop);
		g_signal_handlers_disconnect_by_func (real_directory, forward_files_added_cover, desktop);
		g_signal_handlers_disconnect_by_func (real_directory, forward_files_changed_cover, desktop);

		nemo_directory_unref (real_directory);
	}

	desktop_path = nemo_get_desktop_directory ();
	desktop_uri = g_filename_to_uri (desktop_path, NULL, NULL);
	real_directory = nemo_directory_get_by_uri (desktop_uri);
	g_free (desktop_uri);
	g_free (desktop_path);

	g_signal_connect_object (real_directory, "done_loading",
				 G_CALLBACK (done_loading_callback), desktop, 0);
	g_signal_connect_object (real_directory, "files_added",
				 G_CALLBACK (forward_files_added_cover), desktop, 0);
	g_signal_connect_object (real_directory, "files_changed",
				 G_CALLBACK (forward_files_changed_cover), desktop, 0);

	desktop->details->real_directory = real_directory;
}

static void
desktop_directory_changed_callback (gpointer data)
{
	update_desktop_directory (NEMO_DESKTOP_DIRECTORY (data));
	nemo_directory_force_reload (NEMO_DIRECTORY (data));
}

static void
nemo_desktop_directory_init (NemoDesktopDirectory *desktop)
{
	desktop->details = g_new0 (NemoDesktopDirectoryDetails, 1);

	desktop->details->callbacks = g_hash_table_new_full
		(merged_callback_hash, merged_callback_equal,
		 NULL, (GDestroyNotify)merged_callback_destroy);
	desktop->details->monitors = g_hash_table_new_full (NULL, NULL,
							    NULL, (GDestroyNotify)merged_monitor_destroy);

    desktop->display_number = -1;

	update_desktop_directory (NEMO_DESKTOP_DIRECTORY (desktop));

	g_signal_connect_swapped (nemo_preferences, "changed::" NEMO_PREFERENCES_DESKTOP_IS_HOME_DIR,
				  G_CALLBACK(desktop_directory_changed_callback),
				  desktop);
}

static void
nemo_desktop_directory_class_init (NemoDesktopDirectoryClass *class)
{
	NemoDirectoryClass *directory_class;

	directory_class = NEMO_DIRECTORY_CLASS (class);
	
	G_OBJECT_CLASS (class)->finalize = desktop_finalize;

	directory_class->contains_file = desktop_contains_file;
	directory_class->call_when_ready = desktop_call_when_ready;
	directory_class->cancel_callback = desktop_cancel_callback;
	directory_class->file_monitor_add = desktop_monitor_add;
	directory_class->file_monitor_remove = desktop_monitor_remove;
	directory_class->force_reload = desktop_force_reload;
 	directory_class->are_all_files_seen = desktop_are_all_files_seen;
	directory_class->is_not_empty = desktop_is_not_empty;
	/* Override get_file_list so that we can return the list of files
	 * in NemoDesktopDirectory->details->real_directory,
	 * in addition to the list of standard desktop icons on the desktop.
	 */
	directory_class->get_file_list = desktop_get_file_list;
}
     
