From 216be6798eae8e2dc5150e184500b94738df6ca3 Mon Sep 17 00:00:00 2001
From: Erica Z <zerica@callcc.eu>
Date: Sat, 12 Oct 2024 12:57:37 +0000
Subject: [PATCH] shuffle gapless playback

---
 src/play_queue.blp  |  2 ++
 src/play_queue.vala | 28 +++++++++++++++++++++-------
 src/playbin.vala    | 16 +++++++++++-----
 src/window.vala     |  4 +++-
 4 files changed, 37 insertions(+), 13 deletions(-)

diff --git a/src/play_queue.blp b/src/play_queue.blp
index 5663e5a..e36abfc 100644
--- a/src/play_queue.blp
+++ b/src/play_queue.blp
@@ -11,12 +11,14 @@ template $WaveletPlayQueue: Adw.NavigationPage {
     ScrolledWindow {
       ListView list_view {
         single-click-activate: true;
+        show-separators: true;
 
         activate => $on_song_activate ();
 
         factory: BuilderListItemFactory {
           template ListItem {
             child: Label {
+              styles [ "bold" ]
               halign: start;
               label: bind template.item as <$WaveletSong>.title;
             };
diff --git a/src/play_queue.vala b/src/play_queue.vala
index 0e9109e..b3c7fb7 100644
--- a/src/play_queue.vala
+++ b/src/play_queue.vala
@@ -23,7 +23,9 @@ public class Wavelet.PlayQueue : Adw.NavigationPage {
     [GtkChild] private unowned Gtk.ListView list_view;
 
     private ListStore songs;
-    private uint next_song;
+
+    // this is the index of the song that will play on next on_stream_start
+    private uint next_stream_index;
 
     public signal void play_now (Song song);
     public signal void now_playing (Song song);
@@ -31,7 +33,7 @@ public class Wavelet.PlayQueue : Adw.NavigationPage {
 
     construct {
         this.songs = new ListStore (typeof (Song));
-        this.next_song = 0;
+        this.next_stream_index = 0;
 
         this.list_view.model = new Gtk.NoSelection (this.songs);
     }
@@ -41,22 +43,34 @@ public class Wavelet.PlayQueue : Adw.NavigationPage {
     }
 
     public void queue (Song song) {
+        uint new_index = this.songs.get_n_items ();
         this.songs.append (song);
+        if (new_index == next_stream_index) {
+            this.play_next (song);
+        }
     }
 
     [GtkCallback] private void on_song_activate (uint position) {
-        this.next_song = position;
+        this.next_stream_index = position;
         Song song = (Song) this.songs.get_item (position);
+        this.play_next (song);
         this.play_now (song);
     }
 
     internal void on_stream_start (Playbin playbin) {
-        Song song = (Song) this.songs.get_item (this.next_song);
+        Song song = (Song) this.songs.get_item (this.next_stream_index);
         this.now_playing (song);
 
-        // prepare for next song gapless
-        this.next_song += 1;
-        Song? next_song = (Song?) this.songs.get_item (this.next_song);
+        // prepare for next song ahead of time (gapless)
+        this.next_stream_index += 1;
+        Song? next_song = (Song?) this.songs.get_item (this.next_stream_index);
         this.play_next (next_song);
     }
+
+    internal void restart () {
+        this.next_stream_index = 0;
+        Song song = (Song) this.songs.get_item (0);
+        this.play_next (song);
+        this.play_now (song);
+    }
 }
diff --git a/src/playbin.vala b/src/playbin.vala
index ff572c9..2d4ac46 100644
--- a/src/playbin.vala
+++ b/src/playbin.vala
@@ -44,6 +44,7 @@ class Playbin : Object {
     public int64 duration { get; private set; }
 
     public signal void stream_started ();
+    public signal void stream_over ();
 
     construct {
         this.playbin = Gst.ElementFactory.make ("playbin3", null);
@@ -81,8 +82,6 @@ class Playbin : Object {
             }
 
             if (Gst.MessageType.STREAM_START in message.type) {
-                print ("stream start\n");
-
                 int64 new_duration;
                 assert (this.playbin.query_duration (Gst.Format.TIME, out new_duration));
                 this.duration = new_duration;
@@ -95,7 +94,16 @@ class Playbin : Object {
             }
 
             if (Gst.MessageType.EOS in message.type) {
-                print ("eos\n");
+                string next_uri;
+
+                this.next_uri_lock.lock ();
+                next_uri = this.next_uri;
+                this.next_uri_lock.unlock ();
+
+                if (next_uri == null) {
+                    // no next track was arranged, we're done
+                    this.stream_over ();
+                }
             }
 
             return true;
@@ -181,8 +189,6 @@ class Playbin : Object {
     // called when uri can be switched for gapless playback
     // need async queue because this might be called from a gstreamer thread
     private void on_about_to_finish (dynamic Gst.Element playbin) {
-        print("about to finish\n");
-
         this.next_uri_lock.lock ();
         string? next_uri = this.next_uri;
         this.next_uri_lock.unlock ();
diff --git a/src/window.vala b/src/window.vala
index 845f469..6057cd2 100644
--- a/src/window.vala
+++ b/src/window.vala
@@ -41,6 +41,7 @@ public class Wavelet.Window : Adw.ApplicationWindow {
     private Cancellable cancel_loading_art;
     public bool cover_art_loading { get; set; default = false; }
     public Gdk.Paintable playing_cover_art { get; set; }
+    private Gdk.Paintable next_cover_art;
 
     internal Playbin playbin { get; default = new Playbin (); }
 
@@ -65,13 +66,14 @@ public class Wavelet.Window : Adw.ApplicationWindow {
                         error ("could not get random songs: %s", e.message);
                     }
                     this.shuffle_all_tracks.sensitive = true;
+
+                    this.play_queue.restart ();
                 });
             });
 
             playbin.stream_started.connect (this.play_queue.on_stream_start);
 
             this.play_queue.now_playing.connect ((song) => {
-                print ("now playing %s\n", song.title);
                 this.song = song;
             });