[tepl] LanguageChooserWidget: handle ::key-press-event on the GtkSearchEntry

[Sébastien Wilmet <swilmet src gnome org>]

commit f3d944174816a98d072aac96370b4aa11dc9db9e
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Tue Nov 3 21:57:06 2020 +0100

    LanguageChooserWidget: handle ::key-press-event on the GtkSearchEntry

 tepl/tepl-language-chooser-widget.c | 91 +++++++++++++++++++++++++++++++++++++
 1 file changed, 91 insertions(+)
---
diff --git a/tepl/tepl-language-chooser-widget.c b/tepl/tepl-language-chooser-widget.c
index f27ed5d..281f540 100644
--- a/tepl/tepl-language-chooser-widget.c
+++ b/tepl/tepl-language-chooser-widget.c
@@ -292,6 +292,92 @@ list_box_row_activated_cb (GtkListBox                *list_box,
        emit_language_activated_for_row (chooser_widget, list_box_row);
 }
 
+static void
+move_selection (TeplLanguageChooserWidget *chooser_widget,
+               gint                       how_many)
+{
+       GtkListBoxRow *selected_row;
+       GtkListBoxRow **filtered_children = NULL;
+       gint n_filtered_children;
+       gint pos;
+       gint selected_row_pos = 0;
+       gboolean found = FALSE;
+       gint new_row_to_select_pos;
+       GtkListBoxRow *new_row_to_select;
+
+       selected_row = gtk_list_box_get_selected_row (chooser_widget->priv->list_box);
+       if (selected_row == NULL || !filter_cb (selected_row, chooser_widget))
+       {
+               select_first_row (chooser_widget);
+               return;
+       }
+
+       filtered_children = tepl_utils_list_box_get_filtered_children (chooser_widget->priv->list_box,
+                                                                      filter_cb,
+                                                                      chooser_widget,
+                                                                      &n_filtered_children);
+
+       if (filtered_children == NULL)
+       {
+               goto out;
+       }
+
+       for (pos = 0; filtered_children[pos] != NULL; pos++)
+       {
+               GtkListBoxRow *cur_row = filtered_children[pos];
+
+               if (cur_row == selected_row)
+               {
+                       selected_row_pos = pos;
+                       found = TRUE;
+                       break;
+               }
+       }
+
+       if (!found)
+       {
+               g_warn_if_reached ();
+               goto out;
+       }
+
+       new_row_to_select_pos = selected_row_pos + how_many;
+       new_row_to_select_pos = CLAMP (new_row_to_select_pos, 0, n_filtered_children - 1);
+       new_row_to_select = filtered_children[new_row_to_select_pos];
+       gtk_list_box_select_row (chooser_widget->priv->list_box, new_row_to_select);
+
+out:
+       g_free (filtered_children);
+}
+
+static gboolean
+search_entry_key_press_event_cb (GtkWidget                 *search_entry,
+                                GdkEventKey               *event,
+                                TeplLanguageChooserWidget *chooser_widget)
+{
+       if (event->keyval == GDK_KEY_Down)
+       {
+               move_selection (chooser_widget, 1);
+               return GDK_EVENT_STOP;
+       }
+       else if (event->keyval == GDK_KEY_Up)
+       {
+               move_selection (chooser_widget, -1);
+               return GDK_EVENT_STOP;
+       }
+       else if (event->keyval == GDK_KEY_Page_Down)
+       {
+               move_selection (chooser_widget, 5);
+               return GDK_EVENT_STOP;
+       }
+       else if (event->keyval == GDK_KEY_Page_Up)
+       {
+               move_selection (chooser_widget, -5);
+               return GDK_EVENT_STOP;
+       }
+
+       return GDK_EVENT_PROPAGATE;
+}
+
 static void
 tepl_language_chooser_widget_init (TeplLanguageChooserWidget *chooser_widget)
 {
@@ -337,6 +423,11 @@ tepl_language_chooser_widget_init (TeplLanguageChooserWidget *chooser_widget)
                          G_CALLBACK (search_entry_activate_cb),
                          chooser_widget);
 
+       g_signal_connect (chooser_widget->priv->search_entry,
+                         "key-press-event",
+                         G_CALLBACK (search_entry_key_press_event_cb),
+                         chooser_widget);
+
        g_signal_connect (chooser_widget->priv->list_box,
                          "row-activated",
                          G_CALLBACK (list_box_row_activated_cb),