[gnome-games/wip/exalm/tnum: 12/24] ui: Introduce UndoNotification

[Alexander Mikhaylenko <alexm src gnome org>]

commit 70c340c7d6322b2f589fc8354ec93ca13e70ceb2
Author: Neville <nevilleantony98 gmail com>
Date:   Sat Aug 8 21:26:13 2020 +0530

    ui: Introduce UndoNotification
    
    This is a notification widget which can be used to provide an interface
    to undo an recently done action. It accepts a notification label.
    It also emits undo_button_clicked and close_button_clicked signals.
    
    This will be used in the upcoming commits to allow undoing collection
    deletion.

 data/org.gnome.Games.gresource.xml |  1 +
 data/ui/undo-notification.ui       | 56 +++++++++++++++++++++++++++++++++
 src/meson.build                    |  1 +
 src/ui/undo-notification.vala      | 63 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 121 insertions(+)
---
diff --git a/data/org.gnome.Games.gresource.xml b/data/org.gnome.Games.gresource.xml
index 0f6a64217..e0b862117 100644
--- a/data/org.gnome.Games.gresource.xml
+++ b/data/org.gnome.Games.gresource.xml
@@ -55,5 +55,6 @@
     <file preprocess="xml-stripblanks">ui/shortcuts-window.ui</file>
     <file preprocess="xml-stripblanks">ui/snapshot-row.ui</file>
     <file preprocess="xml-stripblanks">ui/snapshots-list.ui</file>
+    <file preprocess="xml-stripblanks">ui/undo-notification.ui</file>
   </gresource>
 </gresources>
diff --git a/data/ui/undo-notification.ui b/data/ui/undo-notification.ui
new file mode 100644
index 000000000..248242e97
--- /dev/null
+++ b/data/ui/undo-notification.ui
@@ -0,0 +1,56 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<interface>
+  <requires lib="gtk+" version="3.24"/>
+  <template class="GamesUndoNotification" parent="GtkEventBox">
+    <property name="visible">True</property>
+    <property name="valign">start</property>"
+    <property name="halign">center</property>
+    <child>
+      <object class="GtkRevealer">
+        <property name="visible">True</property>
+        <property name="reveal-child" bind-source="GamesUndoNotification" bind-property="reveal"/>
+        <child>
+          <object class="GtkBox">
+            <property name="visible">True</property>
+            <property name="spacing">6</property>
+            <child>
+              <object class="GtkLabel" id="notification_label">
+                <property name="visible">True</property>
+                <property name="ellipsize">end</property>
+                <property name="xalign">0</property>
+                <property name="label" bind-source="GamesUndoNotification" bind-property="label"/>
+                <property name="margin-end">12</property>
+              </object>
+            </child>
+            <child>
+              <object class="GtkButton">
+                <property name="visible">True</property>
+                <property name="label" translatable="yes">_Undo</property>
+                <property name="use-underline">True</property>
+                <signal name="clicked" handler="on_undo_button_clicked"/>
+              </object>
+            </child>
+            <child>
+              <object class="GtkButton">
+                <property name="visible">True</property>
+                <signal name="clicked" handler="on_notification_closed"/>
+                <child>
+                  <object class="GtkImage">
+                    <property name="visible">True</property>
+                    <property name="icon-name">window-close-symbolic</property>
+                  </object>
+                </child>
+                <style>
+                  <class name="flat"/>
+                </style>
+              </object>
+            </child>
+            <style>
+              <class name="app-notification"/>
+            </style>
+          </object>
+        </child>
+      </object>
+    </child>
+  </template>
+</interface>
diff --git a/src/meson.build b/src/meson.build
index 0d44a3f2c..ca368448a 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -170,6 +170,7 @@ vala_sources = [
   'ui/snapshots-list.vala',
   'ui/titlebar-box.vala',
   'ui/ui-view.vala',
+  'ui/undo-notification.vala',
 
   'utils/cairo-blur.vala',
   'utils/composite-cover.vala',
diff --git a/src/ui/undo-notification.vala b/src/ui/undo-notification.vala
new file mode 100644
index 000000000..a7d6a5eb4
--- /dev/null
+++ b/src/ui/undo-notification.vala
@@ -0,0 +1,63 @@
+// This file is part of GNOME Games. License: GPL-3.0+.
+
+[GtkTemplate (ui = "/org/gnome/Games/ui/undo-notification.ui")]
+private class Games.UndoNotification : Gtk.EventBox {
+       private const uint NOTIFICATION_TIMEOUT_SEC = 3;
+
+       public signal void undo ();
+       public signal void closed ();
+
+       private uint timeout_id = 0;
+       private Gtk.EventControllerMotion motion_controller;
+
+       public bool reveal { get; set; }
+       public string label { get; set; }
+
+       construct {
+               motion_controller = new Gtk.EventControllerMotion (this);
+               motion_controller.propagation_phase = Gtk.PropagationPhase.TARGET;
+               motion_controller.enter.connect (() => {
+                       remove_current_timeout_if_exists ();
+               });
+               motion_controller.leave.connect (() => {
+                       set_new_timeout ();
+               });
+       }
+
+       public void show_notification () {
+               reveal = true;
+               remove_current_timeout_if_exists ();
+               set_new_timeout ();
+       }
+
+       private void set_new_timeout () {
+               timeout_id = Timeout.add_seconds (NOTIFICATION_TIMEOUT_SEC, () => {
+                       timeout_id = 0;
+                       reveal = false;
+                       closed ();
+
+                       return Source.REMOVE;
+               });
+       }
+
+       private void remove_current_timeout_if_exists () {
+               if (timeout_id != 0) {
+                       Source.remove (timeout_id);
+                       timeout_id = 0;
+               }
+       }
+
+       [GtkCallback]
+       private void on_undo_button_clicked () {
+               remove_current_timeout_if_exists ();
+               reveal = false;
+               undo ();
+       }
+
+       [GtkCallback]
+       private void on_notification_closed () {
+               remove_current_timeout_if_exists ();
+               reveal = false;
+               closed ();
+       }
+}