[gnome-todo] sidebar: Add placeholder widget to archive list box

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit d0900c2cfaa27d43856134bd0c443fe66009c33a
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Sat Jun 29 21:37:06 2019 -0300

    sidebar: Add placeholder widget to archive list box
    
    When there are no archived task lists, show a standard empty
    placeholder instead of the provide rows.

 src/sidebar/gtd-sidebar.c  | 47 +++++++++++++++++++++++++++++++++++++---------
 src/sidebar/gtd-sidebar.ui | 28 +++++++++++++++++++++++++++
 2 files changed, 66 insertions(+), 9 deletions(-)
---
diff --git a/src/sidebar/gtd-sidebar.c b/src/sidebar/gtd-sidebar.c
index 754e9df..ac6a210 100644
--- a/src/sidebar/gtd-sidebar.c
+++ b/src/sidebar/gtd-sidebar.c
@@ -530,24 +530,53 @@ on_task_list_removed_cb (GtdManager  *manager,
   gtk_list_box_invalidate_filter (listbox);
 }
 
+static gboolean
+filter_archive_listbox_cb (GtkListBoxRow *row,
+                           gpointer       user_data)
+{
+  if (GTD_IS_SIDEBAR_LIST_ROW (row))
+    {
+      GtdTaskList *list;
+
+      list = gtd_sidebar_list_row_get_task_list (GTD_SIDEBAR_LIST_ROW (row));
+      return gtd_task_list_get_archived (list);
+    }
+  else if (GTD_IS_SIDEBAR_PROVIDER_ROW (row))
+    {
+      g_autoptr (GList) lists = NULL;
+      GtdProvider *provider;
+      GList *l;
+
+      provider = gtd_sidebar_provider_row_get_provider (GTD_SIDEBAR_PROVIDER_ROW (row));
+      lists = gtd_provider_get_task_lists (provider);
+
+      for (l = lists; l; l = l->next)
+        {
+          if (gtd_task_list_get_archived (l->data))
+            return TRUE;
+        }
+
+      return FALSE;
+    }
+  else
+    {
+      g_assert_not_reached ();
+    }
+
+  return FALSE;
+}
+
 static gboolean
 filter_listbox_cb (GtkListBoxRow *row,
                    gpointer       user_data)
 {
   GtdTaskList *list;
-  GtkListBox *parent;
-  GtdSidebar *self;
-  gboolean archive;
 
   if (!GTD_IS_SIDEBAR_LIST_ROW (row))
     return TRUE;
 
-  self = GTD_SIDEBAR (user_data);
-  parent = (GtkListBox *) gtk_widget_get_parent (GTK_WIDGET (row));
   list = gtd_sidebar_list_row_get_task_list (GTD_SIDEBAR_LIST_ROW (row));
-  archive = parent == self->archive_listbox;
-
-  return gtd_task_list_get_archived (list) == archive;
+  return !gtd_task_list_get_archived (list);
 }
 
 static gint
@@ -718,7 +747,7 @@ gtd_sidebar_init (GtdSidebar *self)
   gtk_list_box_set_filter_func (self->listbox, filter_listbox_cb, self, NULL);
 
   gtk_list_box_set_sort_func (self->archive_listbox, sort_listbox_cb, self, NULL);
-  gtk_list_box_set_filter_func (self->archive_listbox, filter_listbox_cb, self, NULL);
+  gtk_list_box_set_filter_func (self->archive_listbox, filter_archive_listbox_cb, self, NULL);
 }
 
 void
diff --git a/src/sidebar/gtd-sidebar.ui b/src/sidebar/gtd-sidebar.ui
index 70bc2cc..5e42f26 100644
--- a/src/sidebar/gtd-sidebar.ui
+++ b/src/sidebar/gtd-sidebar.ui
@@ -79,6 +79,34 @@
                     <property name="expand">1</property>
                     <property name="selection_mode">browse</property>
                     <signal name="row-activated" handler="on_listbox_row_activated_cb" object="GtdSidebar" 
swapped="no"/>
+
+                    <child type="placeholder">
+                      <object class="GtkBox">
+                        <property name="halign">center</property>
+                        <property name="valign">center</property>
+                        <property name="hexpand">1</property>
+                        <property name="vexpand">1</property>
+                        <property name="orientation">vertical</property>
+                        <property name="spacing">18</property>
+                        <child>
+                          <object class="GtkImage">
+                            <property name="pixel_size">64</property>
+                            <property name="icon_name">folder-symbolic</property>
+                            <style>
+                              <class name="dim-label"/>
+                            </style>
+                          </object>
+                        </child>
+                        <child>
+                          <object class="GtkLabel">
+                            <property name="label" translatable="yes">No archived lists</property>
+                            <style>
+                              <class name="dim-label"/>
+                            </style>
+                          </object>
+                        </child>
+                      </object>
+                    </child>
                   </object>
                 </property>
               </object>