views/month-cell: Unstyle cells when overflow button is focused

Part-of: <https://gitlab.gnome.org/GNOME/gnome-calendar/-/merge_requests/835>

src/gui/views/gcal-month-cell.blp

@@ -12,6 +12,10 @@ template $GcalMonthCell: Widget {
   receives-default: true;
   focusable: true;
 
+  EventControllerMotion {
+    motion => $on_motion_controller_motion_cb(template);
+  }
+
   Adw.BreakpointBin breakpoint_bin {
     width-request: 50;
     height-request: 50;

src/gui/views/gcal-month-cell.c

@@ -199,6 +199,22 @@ overflow_button_clicked_cb (GtkWidget     *button,
   g_signal_emit (self, signals[SHOW_OVERFLOW], 0, button);
 }
 
+static void
+on_motion_controller_motion_cb (GcalMonthCell            *self,
+                                gdouble                   x,
+                                gdouble                   y,
+                                GtkEventControllerMotion *controller)
+{
+  GtkStateFlags overflow_button_state_flags;
+
+  overflow_button_state_flags = gtk_widget_get_state_flags (self->overflow_button);
+
+  if (overflow_button_state_flags & GTK_STATE_FLAG_PRELIGHT)
+    gtk_widget_add_css_class (GTK_WIDGET (self), "overflow-hovered");
+  else
+    gtk_widget_remove_css_class (GTK_WIDGET (self), "overflow-hovered");
+}
+
 static void
 on_weather_service_weather_changed_cb (GcalWeatherService *weather_service,
                                        GcalMonthCell      *self)
@@ -295,6 +311,7 @@ gcal_month_cell_class_init (GcalMonthCellClass *klass)
   gtk_widget_class_bind_template_child (widget_class, GcalMonthCell, weather_icon);
 
   gtk_widget_class_bind_template_callback (widget_class, overflow_button_clicked_cb);
+  gtk_widget_class_bind_template_callback (widget_class, on_motion_controller_motion_cb);
 
   gtk_widget_class_set_css_name (widget_class, "monthcell");
 

src/theme/style.css

@@ -280,6 +280,10 @@ monthcell {
   outline-offset: 4px;
 }
 
+monthcell.overflow-hovered:hover {
+  background-color: var(--bg-color);
+}
+
 monthcell .overflow {
   border-radius: 6px;
 }