#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

/* GStuff */
#include <glib.h>
#include <glib-object.h>
#include <glib/gi18n.h>

/* Indicator Stuff */
#include <libindicator/indicator.h>
#include <libindicator/indicator-object.h>


#define INDICATOR_DATETIME_TYPE            (indicator_datetime_get_type ())
#define INDICATOR_DATETIME(obj)            (G_TYPE_CHECK_INSTANCE_CAST ((obj), INDICATOR_DATETIME_TYPE, IndicatorDatetime))
#define INDICATOR_DATETIME_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST ((klass), INDICATOR_DATETIME_TYPE, IndicatorDatetimeClass))
#define IS_INDICATOR_DATETIME(obj)         (G_TYPE_CHECK_INSTANCE_TYPE ((obj), INDICATOR_DATETIME_TYPE))
#define IS_INDICATOR_DATETIME_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), INDICATOR_DATETIME_TYPE))
#define INDICATOR_DATETIME_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS ((obj), INDICATOR_DATETIME_TYPE, IndicatorDatetimeClass))

typedef struct _IndicatorDatetime         IndicatorDatetime;
typedef struct _IndicatorDatetimeClass    IndicatorDatetimeClass;
typedef struct _IndicatorDatetimePrivate  IndicatorDatetimePrivate;

struct _IndicatorDatetimeClass {
	IndicatorObjectClass parent_class;
};

struct _IndicatorDatetime {
	IndicatorObject parent;
	IndicatorDatetimePrivate * priv;
};

struct _IndicatorDatetimePrivate {
	GtkLabel * label;
	GtkMenuItem * date;
	GtkMenuItem * calendar;
	guint timer;

	guint idle_measure;
	gint  max_width;
};

#define INDICATOR_DATETIME_GET_PRIVATE(o) \
(G_TYPE_INSTANCE_GET_PRIVATE ((o), INDICATOR_DATETIME_TYPE, IndicatorDatetimePrivate))

GType indicator_datetime_get_type (void);

static void indicator_datetime_class_init (IndicatorDatetimeClass *klass);
static void indicator_datetime_init       (IndicatorDatetime *self);
static void indicator_datetime_dispose    (GObject *object);
static void indicator_datetime_finalize   (GObject *object);
static GtkLabel * get_label               (IndicatorObject * io);
static GtkMenu *  get_menu                (IndicatorObject * io);

/* Indicator Module Config */
INDICATOR_SET_VERSION
INDICATOR_SET_TYPE(INDICATOR_DATETIME_TYPE)

G_DEFINE_TYPE (IndicatorDatetime, indicator_datetime, INDICATOR_OBJECT_TYPE);

static void
indicator_datetime_class_init (IndicatorDatetimeClass *klass)
{
	GObjectClass *object_class = G_OBJECT_CLASS (klass);

	g_type_class_add_private (klass, sizeof (IndicatorDatetimePrivate));

	object_class->dispose = indicator_datetime_dispose;
	object_class->finalize = indicator_datetime_finalize;

	IndicatorObjectClass * io_class = INDICATOR_OBJECT_CLASS(klass);

	io_class->get_label = get_label;
	io_class->get_menu  = get_menu;

	return;
}

static void
indicator_datetime_init (IndicatorDatetime *self)
{
	self->priv = INDICATOR_DATETIME_GET_PRIVATE(self);

	self->priv->label = NULL;
	self->priv->date = NULL;
	self->priv->calendar = NULL;
	self->priv->timer = 0;

	self->priv->idle_measure = 0;
	self->priv->max_width = 0;

	return;
}

static void
indicator_datetime_dispose (GObject *object)
{
	IndicatorDatetime * self = INDICATOR_DATETIME(object);

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

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

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

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

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

	G_OBJECT_CLASS (indicator_datetime_parent_class)->dispose (object);
	return;
}

static void
indicator_datetime_finalize (GObject *object)
{

	G_OBJECT_CLASS (indicator_datetime_parent_class)->finalize (object);
	return;
}

/* Looks at the size of the label, if it grew beyond what we
   thought was the max, make sure it doesn't shrink again. */
static gboolean
idle_measure (gpointer data)
{
	IndicatorDatetime * self = INDICATOR_DATETIME(data);
	self->priv->idle_measure = 0;

	GtkAllocation allocation;
	gtk_widget_get_allocation(GTK_WIDGET(self->priv->label), &allocation);

	if (allocation.width > self->priv->max_width) {
		if (self->priv->max_width != 0) {
			g_warning("Guessed wrong.  We thought the max would be %d but we're now at %d", self->priv->max_width, allocation.width);
		}
		self->priv->max_width = allocation.width;
		gtk_widget_set_size_request(GTK_WIDGET(self->priv->label), self->priv->max_width, -1);
	}

	return FALSE;
}

/* Updates the label to be the current time. */
static void
update_label (IndicatorDatetime * io)
{
	IndicatorDatetime * self = INDICATOR_DATETIME(io);

	if (self->priv->label == NULL) return;

	gchar longstr[128];
	time_t t;
	struct tm *ltime;

	t = time(NULL);
	ltime = localtime(&t);
	if (ltime == NULL) {
		g_debug("Error getting local time");
		gtk_label_set_label(self->priv->label, _("Error getting time"));
		return;
	}

	strftime(longstr, 128, "%l:%M %p", ltime);
	
	gchar * utf8 = g_locale_to_utf8(longstr, -1, NULL, NULL, NULL);
	gtk_label_set_label(self->priv->label, utf8);
	g_free(utf8);

	if (self->priv->idle_measure == 0) {
		self->priv->idle_measure = g_idle_add(idle_measure, io);
	}

	if (self->priv->date == NULL) return;

	/* Note: may require some localization tweaks */
	strftime(longstr, 128, "%A, %e %B %Y", ltime);
	
	utf8 = g_locale_to_utf8(longstr, -1, NULL, NULL, NULL);
	gtk_menu_item_set_label(self->priv->date, utf8);
	g_free(utf8);

	return;
}

/* Runs every minute and updates the time */
gboolean
minute_timer_func (gpointer user_data)
{
	IndicatorDatetime * self = INDICATOR_DATETIME(user_data);

	if (self->priv->label != NULL) {
		update_label(self);
		return TRUE;
	} else {
		self->priv->timer = 0;
		return FALSE;
	}

	return FALSE;
}

static void
activate_cb (GtkWidget *widget, const gchar *command)
{
	GError * error = NULL;

	if (!g_spawn_command_line_async(command, &error)) {
		g_warning("Unable to start %s: %s", (char *)command, error->message);
		g_error_free(error);
	}
}

/* Does a quick meausre of how big the string is in
   pixels with a Pango layout */
static gint
measure_string (GtkStyle * style, PangoContext * context, const gchar * string)
{
	PangoLayout * layout = pango_layout_new(context);
	pango_layout_set_text(layout, string, -1);
	pango_layout_set_font_description(layout, style->font_desc);

	gint width;
	pango_layout_get_pixel_size(layout, &width, NULL);
	g_object_unref(layout);
	return width;
}

#define FAT_NUMBER 8

/* Try to get a good guess at what a maximum width of the entire
   string would be. */
static void
guess_label_size (IndicatorDatetime * self)
{
	GtkStyle * style = gtk_widget_get_style(GTK_WIDGET(self->priv->label));
	PangoContext * context = gtk_widget_get_pango_context(GTK_WIDGET(self->priv->label));

	/* TRANSLATORS: This string is used for measuring the size of
	   the font used for showing the time and is not shown to the
	   user anywhere. */
	gchar * am_str = g_strdup_printf(_("%d%d:%d%d AM"), FAT_NUMBER, FAT_NUMBER, FAT_NUMBER, FAT_NUMBER);
	gint am_width = measure_string(style, context, am_str);
	g_free(am_str);

	/* TRANSLATORS: This string is used for measuring the size of
	   the font used for showing the time and is not shown to the
	   user anywhere. */
	gchar * pm_str = g_strdup_printf(_("%d%d:%d%d PM"), FAT_NUMBER, FAT_NUMBER, FAT_NUMBER, FAT_NUMBER);
	gint pm_width = measure_string(style, context, pm_str);
	g_free(pm_str);

	self->priv->max_width = MAX(am_width, pm_width);
	gtk_widget_set_size_request(GTK_WIDGET(self->priv->label), self->priv->max_width, -1);

	g_debug("Guessing max time width: %d", self->priv->max_width);

	return;
}

/* React to the style changing, which could mean an font
   update. */
static void
style_changed (GtkWidget * widget, GtkStyle * oldstyle, gpointer data)
{
	g_debug("New style for time label");
	IndicatorDatetime * self = INDICATOR_DATETIME(data);
	guess_label_size(self);
	update_label(self);
	return;
}

/* Grabs the label.  Creates it if it doesn't
   exist already */
static GtkLabel *
get_label (IndicatorObject * io)
{
	IndicatorDatetime * self = INDICATOR_DATETIME(io);

	/* If there's not a label, we'll build ourselves one */
	if (self->priv->label == NULL) {
		self->priv->label = GTK_LABEL(gtk_label_new("Time"));
		g_object_ref(G_OBJECT(self->priv->label));
		g_signal_connect(G_OBJECT(self->priv->label), "style-set", G_CALLBACK(style_changed), self);
		guess_label_size(self);
		update_label(self);
		gtk_widget_show(GTK_WIDGET(self->priv->label));
	}

	if (self->priv->timer == 0) {
		self->priv->timer = g_timeout_add_seconds(60, minute_timer_func, self);
	}

	return self->priv->label;
}

static void
check_for_calendar_application (IndicatorDatetime * self)
{
	GtkMenuItem * item = self->priv->calendar;
	g_return_if_fail (item != NULL);

	gchar *evo = g_find_program_in_path("evolution");
	if (evo != NULL) {
		g_signal_connect (GTK_MENU_ITEM (item), "activate",
						  G_CALLBACK (activate_cb), "evolution -c calendar");
		gtk_widget_set_sensitive (GTK_WIDGET (item), TRUE);
		gtk_widget_show(GTK_WIDGET(item));
		g_free(evo);
	} else {
		gtk_widget_hide(GTK_WIDGET(item));
	}
}

static GtkMenu *
get_menu (IndicatorObject * io)
{
	IndicatorDatetime * self = INDICATOR_DATETIME(io);

	GtkWidget * menu = NULL;
	GtkWidget * item = NULL;

	menu = gtk_menu_new();
	
	if (self->priv->date == NULL) {
		item = gtk_menu_item_new_with_label("No date yet...");
		gtk_widget_set_sensitive (GTK_WIDGET (item), FALSE);
		gtk_menu_shell_append(GTK_MENU_SHELL(menu), item);
		self->priv->date = GTK_MENU_ITEM (item);
		update_label(self);
	}

	if (self->priv->calendar == NULL) {
		item = gtk_menu_item_new_with_label(_("Open Calendar"));
		/* insensitive until we check for available apps */
		gtk_widget_set_sensitive (GTK_WIDGET (item), FALSE);
		gtk_menu_shell_append(GTK_MENU_SHELL(menu), item);
		self->priv->calendar = GTK_MENU_ITEM (item);
	}
 
	gtk_menu_shell_append (GTK_MENU_SHELL (menu),
						   gtk_separator_menu_item_new ());

	GtkWidget *settings_mi = gtk_menu_item_new_with_label (_("Set Time and Date..."));
	g_signal_connect (GTK_MENU_ITEM (settings_mi), "activate",
					  G_CALLBACK (activate_cb), "time-admin");
	gtk_menu_shell_append (GTK_MENU_SHELL(menu), settings_mi);
	gtk_widget_show(settings_mi);

	/* show_all to reveal the separator */
	gtk_widget_show_all(menu);

	/* Note: maybe should move that to an idle loop if that helps with
	   boot performance	*/
	check_for_calendar_application (self);

	return GTK_MENU(menu);
}