From 68b440920c1c74b70d1f3090f4626f1840e3f5b7 Mon Sep 17 00:00:00 2001
From: Kingkor Roy Tirtho <krtirtho@gmail.com>
Date: Tue, 19 Jul 2022 12:49:47 +0600
Subject: [PATCH] support for presearch next track lowers the track change
 latency

---
 lib/hooks/useUpdateChecker.dart |  4 ++--
 lib/provider/Playback.dart      | 30 ++++++++++++++++++++++++++++--
 2 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/lib/hooks/useUpdateChecker.dart b/lib/hooks/useUpdateChecker.dart
index 1efac132..672bcb4b 100644
--- a/lib/hooks/useUpdateChecker.dart
+++ b/lib/hooks/useUpdateChecker.dart
@@ -54,8 +54,8 @@ void useUpdateChecker(WidgetRef ref) {
       showDialog(
           context: context,
           builder: (context) {
-            final url =
-                "https://github.com/KRTirtho/spotube/releases/tag/v${value.last}";
+            const url =
+                "https://spotube.netlify.app/other-downloads/stable-downloads";
             return AlertDialog(
               title: const Text("Spotube has an update"),
               actions: [
diff --git a/lib/provider/Playback.dart b/lib/provider/Playback.dart
index 0cd7e205..e6431933 100644
--- a/lib/provider/Playback.dart
+++ b/lib/provider/Playback.dart
@@ -58,6 +58,8 @@ class Playback extends PersistedChangeNotifier {
   // internal stuff
   final List<StreamSubscription> _subscriptions;
   final _logger = getLogger(Playback);
+  // state of preSearch used inside [onPositionChanged]
+  bool _isPreSearching = false;
 
   PlaybackStatus status;
 
@@ -110,6 +112,26 @@ class Playback extends PersistedChangeNotifier {
             currentDuration = await player.getDuration() ?? Duration.zero;
             notifyListeners();
           }
+
+          final currentTrackIndex =
+              playlist!.tracks.indexWhere((t) => t.id == track?.id);
+
+          // when the track progress is above 80%, track isn't the last
+          // and is not already fetch and nothing is fetching currently
+          if (pos.inSeconds > currentDuration.inSeconds * .8 &&
+              playlist != null &&
+              currentTrackIndex != playlist!.tracks.length - 1 &&
+              playlist!.tracks.elementAt(currentTrackIndex + 1)
+                  is! SpotubeTrack &&
+              !_isPreSearching) {
+            _isPreSearching = true;
+            playlist!.tracks[currentTrackIndex + 1] = await toSpotubeTrack(
+              playlist!.tracks[currentTrackIndex + 1],
+            ).then((v) {
+              _isPreSearching = false;
+              return v;
+            });
+          }
         }),
       ]);
     }());
@@ -389,7 +411,9 @@ class Playback extends PersistedChangeNotifier {
         (playlist!.trackIds.indexOf(track!.id!) + 1).toInt();
     // checking if there's any track available forward
     if (nextTrackIndex > (playlist?.tracks.length ?? 0) - 1) return;
-    await play(playlist!.tracks.elementAt(nextTrackIndex));
+    await play(playlist!.tracks.elementAt(nextTrackIndex)).then((_) {
+      playlist!.tracks[nextTrackIndex] = track!;
+    });
   }
 
   Future<void> seekBackward() async {
@@ -398,7 +422,9 @@ class Playback extends PersistedChangeNotifier {
         (playlist!.trackIds.indexOf(track!.id!) - 1).toInt();
     // checking if there's any track available behind
     if (prevTrackIndex < 0) return;
-    await play(playlist!.tracks.elementAt(prevTrackIndex));
+    await play(playlist!.tracks.elementAt(prevTrackIndex)).then((_) {
+      playlist!.tracks[prevTrackIndex] = track!;
+    });
   }
 
   @override