core: Get week start day from settings portal

Uses the already available settings portal in GcalContext to fetch and
track changes in global "week start day" desktop setting. Will use this
later to redraw views.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-calendar/-/merge_requests/822>

src/core/gcal-context.c

@@ -23,6 +23,12 @@
 #include "gcal-context.h"
 #include "gcal-time-zone-monitor.h"
 
+#include <gdesktop-enums.h>
+#include "gdesktop-enum-types.h"
+
+#define DESKTOP_SETTINGS_CALENDAR_NAMESPACE "org.gnome.desktop.calendar"
+#define CALENDAR_WEEK_START_DAY_KEY "week-start-day"
+
 struct _GcalContext
 {
   GObject             parent;
@@ -37,6 +43,7 @@ struct _GcalContext
   GcalWeatherService *weather_service;
 
   GcalTimeZoneMonitor   *timezone_monitor;
+  GDesktopWeekday        week_start_day;
 };
 
 G_DEFINE_TYPE (GcalContext, gcal_context, G_TYPE_OBJECT)
@@ -51,6 +58,7 @@ enum
   PROP_TIME_FORMAT,
   PROP_TIMEZONE,
   PROP_WEATHER_SERVICE,
+  PROP_WEEK_START_DAY,
   N_PROPS
 };
 
@@ -86,6 +94,29 @@ set_time_format_from_variant (GcalContext *self,
   g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_TIME_FORMAT]);
 }
 
+static void
+set_week_start_day_from_variant (GcalContext *self,
+                                 GVariant    *variant)
+{
+  g_autofree gchar *enum_format = NULL;
+  const char *weekday_nick = NULL;
+  GEnumValue *weekday = NULL;
+
+  g_assert (g_variant_type_equal (g_variant_get_type (variant), "s"));
+
+  /* extract the day as enum value by name */
+  weekday_nick = g_variant_get_string (variant, NULL);
+  weekday = g_enum_get_value_by_nick (g_type_class_get (G_DESKTOP_TYPE_WEEKDAY), weekday_nick);
+
+  if (!weekday || self->week_start_day == weekday->value)
+    return;
+
+  self->week_start_day = weekday->value;
+  g_debug ("Setting week start day to %s", weekday_nick);
+
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_WEEK_START_DAY]);
+}
+
 static gboolean
 read_time_format (GcalContext *self)
 {
@@ -104,6 +135,7 @@ read_time_format (GcalContext *self)
 
   if (error)
     {
+      g_warning ("Failed to read the clock-format setting through the settings portal: %s", error->message);
       return FALSE;
     }
 
@@ -115,6 +147,35 @@ read_time_format (GcalContext *self)
   return TRUE;
 }
 
+static gboolean
+read_week_start_day (GcalContext *self)
+{
+  g_autoptr (GVariant) other_child = NULL;
+  g_autoptr (GVariant) child = NULL;
+  g_autoptr (GVariant) ret = NULL;
+  g_autoptr (GError) error = NULL;
+
+  ret = g_dbus_proxy_call_sync (self->settings_portal,
+                                "Read",
+                                g_variant_new ("(ss)", DESKTOP_SETTINGS_CALENDAR_NAMESPACE, CALENDAR_WEEK_START_DAY_KEY),
+                                G_DBUS_CALL_FLAGS_NONE,
+                                G_MAXINT,
+                                NULL,
+                                &error);
+
+  if (error)
+    {
+      g_warning ("Failed to read the week-start-day setting through the settings portal: %s", error->message);
+      return FALSE;
+    }
+
+  g_variant_get (ret, "(v)", &child);
+  g_variant_get (child, "v", &other_child);
+
+  set_week_start_day_from_variant (self, other_child);
+
+  return TRUE;
+}
 
 /*
  * Callbacks
@@ -141,6 +202,12 @@ on_portal_proxy_signal_cb (GDBusProxy  *proxy,
     {
       set_time_format_from_variant (self, value);
     }
+
+  if (g_strcmp0 (namespace, DESKTOP_SETTINGS_CALENDAR_NAMESPACE) == 0 &&
+      g_strcmp0 (name, CALENDAR_WEEK_START_DAY_KEY) == 0)
+    {
+      set_week_start_day_from_variant (self, value);
+    }
 }
 
 static void
@@ -220,6 +287,10 @@ gcal_context_get_property (GObject    *object,
       g_value_set_object (value, self->weather_service);
       break;
 
+    case PROP_WEEK_START_DAY:
+      g_value_set_enum (value, self->week_start_day);
+      break;
+
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
     }
@@ -240,6 +311,7 @@ gcal_context_set_property (GObject      *object,
     case PROP_TIME_FORMAT:
     case PROP_TIMEZONE:
     case PROP_WEATHER_SERVICE:
+    case PROP_WEEK_START_DAY:
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
     }
@@ -298,6 +370,11 @@ gcal_context_class_init (GcalContextClass *klass)
                                                           GCAL_TYPE_WEATHER_SERVICE,
                                                           G_PARAM_READABLE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
 
+  properties[PROP_WEEK_START_DAY] =
+    g_param_spec_enum ("week-start-day", NULL, NULL,
+                       G_DESKTOP_TYPE_WEEKDAY, get_first_weekday_iso (),
+                       G_PARAM_READABLE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
   g_object_class_install_properties (object_class, N_PROPS, properties);
 }
 
@@ -454,9 +531,16 @@ gcal_context_get_weather_service (GcalContext *self)
 void
 gcal_context_startup (GcalContext *self)
 {
+  gboolean time_format_available;
+  gboolean week_start_day_available;
+
   g_return_if_fail (GCAL_IS_CONTEXT (self));
 
-  if (read_time_format (self))
+  time_format_available = read_time_format (self);
+  week_start_day_available = read_week_start_day (self);
+
+  /* NOTE: can't inline because of short-circuiting */
+  if (time_format_available || week_start_day_available)
     {
       g_signal_connect (self->settings_portal,
                         "g-signal",