[gnome-games/wip/aplazas/app-menu] ui: Add Help to the application menu

[Adrien Plazas <aplazas src gnome org>]

commit 7caa818e2872431c1af488a8e3e0afebb45a580b
Author: Adrien Plazas <kekun plazas laposte net>
Date:   Sat Jun 23 09:54:37 2018 +0200

    ui: Add Help to the application menu
    
    This will open the application's documentation page as we don't have
    offline documentation.

 data/ui/collection-header-bar.ui |  8 ++++++++
 src/ui/application.vala          | 15 +++++++++++++++
 2 files changed, 23 insertions(+)
---
diff --git a/data/ui/collection-header-bar.ui b/data/ui/collection-header-bar.ui
index 1696897..76cf147 100644
--- a/data/ui/collection-header-bar.ui
+++ b/data/ui/collection-header-bar.ui
@@ -104,6 +104,14 @@
             <property name="visible">True</property>
           </object>
         </child>
+        <child>
+          <object class="GtkModelButton">
+            <property name="can_focus">True</property>
+            <property name="text" translatable="yes">Help</property>
+            <property name="action-name">app.help</property>
+            <property name="visible">True</property>
+          </object>
+        </child>
         <child>
           <object class="GtkModelButton">
             <property name="can_focus">True</property>
diff --git a/src/ui/application.vala b/src/ui/application.vala
index 5f562d4..d21bb7d 100644
--- a/src/ui/application.vala
+++ b/src/ui/application.vala
@@ -3,6 +3,8 @@
 private extern const string VERSION;
 
 public class Games.Application : Gtk.Application {
+       const string HELP_URI = "https://wiki.gnome.org/Apps/Games/Documentation";;
+
        private Database database;
 
        private PreferencesWindow preferences_window;
@@ -40,6 +42,10 @@ public class Games.Application : Gtk.Application {
                preferences_action.activate.connect (preferences);
                add_action (preferences_action);
 
+               SimpleAction help_action = new SimpleAction ("help", null);
+               help_action.activate.connect (help);
+               add_action (help_action);
+
                SimpleAction about_action = new SimpleAction ("about", null);
                about_action.activate.connect (about);
                add_action (about_action);
@@ -310,6 +316,15 @@ public class Games.Application : Gtk.Application {
                });
        }
 
+       private void help () {
+               try {
+                       Gtk.show_uri_on_window (active_window, HELP_URI, Gtk.get_current_event_time ());
+               }
+               catch (Error e) {
+                       critical (e.message);
+               }
+       }
+
        private void about () {
                Gtk.AboutDialog dialog = new Gtk.AboutDialog ();
                dialog.set_destroy_with_parent (true);