From ab1a4c6c80a98b37c1ffac756f6400e6f185189d Mon Sep 17 00:00:00 2001
From: Peter Nelson <peter1138@openttd.org>
Date: Mon, 27 Nov 2023 12:52:31 +0000
Subject: [PATCH] Change: Don't restart playback when toggling playlist
 shuffle.

Instead update the selected playlist entry for the current song.
---
 src/music_gui.cpp | 28 ++++++++++++++++++++++------
 1 file changed, 22 insertions(+), 6 deletions(-)

diff --git a/src/music_gui.cpp b/src/music_gui.cpp
index ef6cc83606..490d80817e 100644
--- a/src/music_gui.cpp
+++ b/src/music_gui.cpp
@@ -87,6 +87,7 @@ struct MusicSystem {
 	void PlaylistClear();
 
 private:
+	void SetPositionBySetIndex(uint set_index);
 	void ChangePlaylistPosition(int ofs);
 	int playlist_position;
 
@@ -184,30 +185,45 @@ void MusicSystem::ChangeMusicSet(const std::string &set_name)
 	InvalidateWindowData(WC_MUSIC_WINDOW, 0, 1, true);
 }
 
-/** Enable shuffle mode and restart playback */
+/**
+ * Set playlist position by set index.
+ * @param set_index Set index to select.
+ */
+void MusicSystem::SetPositionBySetIndex(uint set_index)
+{
+	auto it = std::find_if(std::begin(this->active_playlist), std::end(this->active_playlist), [&set_index](const PlaylistEntry &ple) { return ple.set_index == set_index; });
+	if (it != std::end(this->active_playlist)) this->playlist_position = std::distance(std::begin(this->active_playlist), it);
+}
+
+/**
+ * Enable shuffle mode.
+ */
 void MusicSystem::Shuffle()
 {
 	_settings_client.music.shuffle = true;
 
+	uint set_index = this->active_playlist[this->playlist_position].set_index;
 	this->active_playlist = this->displayed_playlist;
 	for (size_t i = 0; i < this->active_playlist.size(); i++) {
 		size_t shuffle_index = InteractiveRandom() % (this->active_playlist.size() - i);
 		std::swap(this->active_playlist[i], this->active_playlist[i + shuffle_index]);
 	}
-
-	if (_settings_client.music.playing) this->Play();
+	this->SetPositionBySetIndex(set_index);
 
 	InvalidateWindowData(WC_MUSIC_TRACK_SELECTION, 0);
 	InvalidateWindowData(WC_MUSIC_WINDOW, 0);
 }
 
-/** Disable shuffle and restart playback */
+/**
+ * Disable shuffle mode.
+ */
 void MusicSystem::Unshuffle()
 {
 	_settings_client.music.shuffle = false;
-	this->active_playlist = this->displayed_playlist;
 
-	if (_settings_client.music.playing) this->Play();
+	uint set_index = this->active_playlist[this->playlist_position].set_index;
+	this->active_playlist = this->displayed_playlist;
+	this->SetPositionBySetIndex(set_index);
 
 	InvalidateWindowData(WC_MUSIC_TRACK_SELECTION, 0);
 	InvalidateWindowData(WC_MUSIC_WINDOW, 0);