/* -*- mode: C; c-file-style: "linux"; indent-tabs-mode: t -*-
 * gnome-wall-clock.h - monitors TZ setting files and signals changes
 *
 * Copyright (C) 2010 Red Hat, Inc.
 * Copyright (C) 2011 Red Hat, Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 * 02111-1307, USA.
 *
 * Author: Colin Walters <walters@verbum.org>
 */

#include "config.h"

#include <glib/gi18n-lib.h>

#define GNOME_DESKTOP_USE_UNSTABLE_API
#include "gnome-wall-clock.h"
#include <gdesktop-enums.h>
#include "gnome-datetime-source.h"

struct _GnomeWallClockPrivate {
	guint clock_update_id;
	
	char *clock_string;
	
	GFileMonitor *tz_monitor;
	GSettings    *desktop_settings;
};

enum {
	PROP_0,
	PROP_CLOCK
};

G_DEFINE_TYPE (GnomeWallClock, gnome_wall_clock, G_TYPE_OBJECT);

static gboolean update_clock (gpointer data);
static void on_schema_change (GSettings *schema,
                              const char *key,
                              gpointer user_data);
static void on_tz_changed (GFileMonitor *monitor,
                           GFile        *file,
                           GFile        *other_file,
                           GFileMonitorEvent *event,
                           gpointer      user_data);


static void
gnome_wall_clock_init (GnomeWallClock *self)
{
	GFile *tz;

	self->priv = G_TYPE_INSTANCE_GET_PRIVATE (self, GNOME_TYPE_WALL_CLOCK, GnomeWallClockPrivate);
	
	self->priv->clock_string = NULL;
	
	tz = g_file_new_for_path ("/etc/localtime");
	self->priv->tz_monitor = g_file_monitor_file (tz, 0, NULL, NULL);
	g_object_unref (tz);
	
	g_signal_connect (self->priv->tz_monitor, "changed", G_CALLBACK (on_tz_changed), self);
	
	self->priv->desktop_settings = g_settings_new ("org.gnome.desktop.interface");
	g_signal_connect (self->priv->desktop_settings, "changed", G_CALLBACK (on_schema_change), self);

	update_clock (self);
}

static void
gnome_wall_clock_dispose (GObject *object)
{
	GnomeWallClock *self = GNOME_WALL_CLOCK (object);

	if (self->priv->clock_update_id) {
		g_source_remove (self->priv->clock_update_id);
		self->priv->clock_update_id = 0;
	}

	if (self->priv->tz_monitor != NULL) {
		g_object_unref (self->priv->tz_monitor);
		self->priv->tz_monitor = NULL;
	}

	if (self->priv->desktop_settings != NULL) {
		g_object_unref (self->priv->desktop_settings);
		self->priv->desktop_settings = NULL;
	}

	G_OBJECT_CLASS (gnome_wall_clock_parent_class)->dispose (object);
}

static void
gnome_wall_clock_finalize (GObject *object)
{
	GnomeWallClock *self = GNOME_WALL_CLOCK (object);

	g_free (self->priv->clock_string);

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

static void
gnome_wall_clock_get_property (GObject    *gobject,
			       guint       prop_id,
			       GValue     *value,
			       GParamSpec *pspec)
{
	GnomeWallClock *self = GNOME_WALL_CLOCK (gobject);

	switch (prop_id)
	{
	case PROP_CLOCK:
		g_value_set_string (value, self->priv->clock_string);
		break;
	default:
		G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
		break;
	}
}

static void
gnome_wall_clock_class_init (GnomeWallClockClass *klass)
{
	GObjectClass *gobject_class = G_OBJECT_CLASS (klass);

	gobject_class->get_property = gnome_wall_clock_get_property;
	gobject_class->dispose = gnome_wall_clock_dispose;
	gobject_class->finalize = gnome_wall_clock_finalize;

	/**
	 * GnomeWallClock:clock:
	 *
	 * A formatted string representing the current clock display.
	 */
	g_object_class_install_property (gobject_class,
					 PROP_CLOCK,
					 g_param_spec_string ("clock",
							      "",
							      "",
							      NULL,
							      G_PARAM_READABLE));


	g_type_class_add_private (gobject_class, sizeof (GnomeWallClockPrivate));
}

static gboolean
update_clock (gpointer data)
{
	GnomeWallClock   *self = data;
	GDesktopClockFormat clock_format;
	const char *format_string;
	gboolean show_date;
	gboolean show_seconds;
	GSource *source;
	GDateTime *now;
	GDateTime *expiry;

	clock_format = g_settings_get_enum (self->priv->desktop_settings, "clock-format");
	show_date = g_settings_get_boolean (self->priv->desktop_settings, "clock-show-date");
	show_seconds = g_settings_get_boolean (self->priv->desktop_settings, "clock-show-seconds");

	now = g_date_time_new_now_local ();
	if (show_seconds)
		expiry = g_date_time_add_seconds (now, 1);
	else
		expiry = g_date_time_add_seconds (now, 60 - g_date_time_get_second (now));
  
	if (self->priv->clock_update_id)
		g_source_remove (self->priv->clock_update_id);
  
	source = _gnome_datetime_source_new (now, expiry, TRUE);
	g_source_set_priority (source, G_PRIORITY_HIGH);
	g_source_set_callback (source, update_clock, self, NULL);
	self->priv->clock_update_id = g_source_attach (source, NULL);
	g_source_unref (source);

	if (clock_format == G_DESKTOP_CLOCK_FORMAT_24H) {
		if (show_date)
			/* Translators: This is the time format with date used
			   in 24-hour mode. */
			format_string = show_seconds ? _("%a %b %e, %R:%S")
				: _("%a %b %e, %R");
		else
			/* Translators: This is the time format without date used
			   in 24-hour mode. */
			format_string = show_seconds ? _("%a %R:%S")
				: _("%a %R");
	} else {
		if (show_date)
			/* Translators: This is a time format with date used
			   for AM/PM. */
			format_string = show_seconds ? _("%a %b %e, %l:%M:%S %p")
				: _("%a %b %e, %l:%M %p");
		else
			/* Translators: This is a time format without date used
			   for AM/PM. */
			format_string = show_seconds ? _("%a %l:%M:%S %p")
				: _("%a %l:%M %p");
	}

	g_free (self->priv->clock_string);
	self->priv->clock_string = g_date_time_format (now, format_string);

	g_date_time_unref (now);
	g_date_time_unref (expiry);
      
	g_object_notify ((GObject*)self, "clock");

	return FALSE;
}

static void
on_schema_change (GSettings *schema,
                  const char *key,
                  gpointer user_data)
{
	update_clock (user_data);
}

static void
on_tz_changed (GFileMonitor      *monitor,
               GFile             *file,
               GFile             *other_file,
               GFileMonitorEvent *event,
               gpointer           user_data)
{
	update_clock (user_data);
}

const char *
gnome_wall_clock_get_clock (GnomeWallClock *clock)
{
	return clock->priv->clock_string;
}
