month-view: implement GcalView::wil_add_event vfunc

src/gcal-month-view.c

@@ -1304,7 +1304,29 @@ static gboolean
 gcal_month_view_will_add_event (GcalView        *view,
                                 GcalEventWidget *event)
 {
-  ;
+  GcalMonthViewPrivate *priv;
+
+  icaltimetype *start_date;
+  gboolean is_in_range;
+
+  const gchar* event_uuid;
+
+  g_return_val_if_fail (GCAL_IS_MONTH_VIEW (view), FALSE);
+  priv = gcal_month_view_get_instance_private (GCAL_MONTH_VIEW (view));
+
+  if (priv->date == NULL)
+    return FALSE;
+
+  start_date = gcal_event_widget_get_date (event);
+  is_in_range = (priv->date->month == start_date->month &&
+                 priv->date->year == start_date->year);
+  g_free (start_date);
+
+  if (!is_in_range)
+    return FALSE;
+
+  event_uuid = gcal_event_widget_peek_uuid (event);
+  return !(gcal_month_view_get_by_uuid (view, event_uuid) != NULL);
 }
 
 /* Public API */