Merge pull request 'Makes the ⏮ and ⏭ on the Now Playing screen work' (#14) from rh/next-prev into main

Reviewed-on: https://codeberg.org/cool-tech-zone/tangara-fw/pulls/14
Reviewed-by: cooljqln <cooljqln@noreply.codeberg.org>

ldoc-stubs/queue.lua

@@ -19,4 +19,10 @@ queue.replay = types.Property
 -- @see types.Property
 queue.random = types.Property
 
+--- Moves forward in the play queue, looping back around to the beginning if repeat is on.
+function queue.next() end
+
+--- Moves backward in the play queue, looping back around to the end if repeat is on.
+function queue.previous() end
+
 return queue

lua/playing.lua

@@ -5,6 +5,15 @@ local font = require("font")
 local playback = require("playback")
 local queue = require("queue")
 
+local img = {
+  play = "//lua/img/play.png",
+  pause = "//lua/img/pause.png",
+  next = "//lua/img/next.png",
+  next_disabled = "//lua/img/next_disabled.png",
+  prev = "//lua/img/prev.png",
+  prev_disabled = "//lua/img/prev_disabled.png",
+}
+
 return function(opts)
   local screen = {}
   screen.root = lvgl.Object(nil, {
@@ -106,19 +115,20 @@ return function(opts)
 
   controls:Object({ flex_grow = 1, h = 1 }) -- spacer
 
-  controls:Image {
-    src = "//lua/img/prev.png",
-  }
+  local prev_btn = controls:Button {}
+  prev_btn:onClicked(queue.previous)
+  local prev_img = prev_btn:Image { src = img.prev_disabled }
+
   local play_pause_btn = controls:Button {}
   play_pause_btn:onClicked(function()
     playback.playing:set(not playback.playing:get())
   end)
-  local play_pause_img = play_pause_btn:Image {
-    src = "//lua/img/pause.png",
-  }
-  controls:Image {
-    src = "//lua/img/next.png",
-  }
+  local play_pause_img = play_pause_btn:Image { src = img.pause }
+
+  local next_btn = controls:Button {}
+  next_btn:onClicked(queue.next)
+  local next_img = next_btn:Image { src = img.next_disabled }
+
   controls:Object({ flex_grow = 1, h = 1 }) -- spacer
 
   local end_time = controls:Label {
@@ -136,9 +146,9 @@ return function(opts)
   screen.bindings = {
     playback.playing:bind(function(playing)
       if playing then
-        play_pause_img:set_src("//lua/img/pause.png")
+        play_pause_img:set_src(img.pause)
       else
-        play_pause_img:set_src("//lua/img/play.png")
+        play_pause_img:set_src(img.play)
       end
     end),
     playback.position:bind(function(pos)
@@ -162,6 +172,13 @@ return function(opts)
     queue.position:bind(function(pos)
       if not pos then return end
       playlist_pos:set { text = tostring(pos) }
+
+      next_img:set_src(
+        pos < queue.size:get() and img.next or img.next_disabled
+      )
+      prev_img:set_src(
+        pos > 1 and img.prev or img.prev_disabled
+      )
     end),
     queue.size:bind(function(num)
       if not num then return end

luals-stubs/queue.lua

@@ -8,4 +8,7 @@
 --- @field random Property  Determines whether, when progressing to the next track in the queue, the next track will be chosen randomly. The random selection algorithm used is a Miller Shuffle, which guarantees that no repeat selections will be made until every item in the queue has been played. Writeable.
 local queue = {}
 
+function queue.next() end
+function queue.previous() end
+
 return queue

src/audio/track_queue.cpp

@@ -200,10 +200,13 @@ auto TrackQueue::next() -> void {
     shuffle_->next();
     pos_ = shuffle_->current();
   } else {
-    pos_++;
-    if (pos_ >= tracks_.size() && repeat_) {
+    if (pos_ + 1 >= tracks_.size()) {
+      if (repeat_) {
         pos_ = 0;
       }
+    } else {
+      pos_++;
+    }
   }
 
   notifyChanged(true);

src/ui/include/ui_fsm.hpp

@@ -164,6 +164,9 @@ class Lua : public UiState {
   auto SetPlaying(const lua::LuaValue&) -> bool;
   auto SetRandom(const lua::LuaValue&) -> bool;
   auto SetRepeat(const lua::LuaValue&) -> bool;
+
+  auto QueueNext(lua_State*) -> int;
+  auto QueuePrevious(lua_State*) -> int;
 };
 
 }  // namespace states

src/ui/ui_fsm.cpp

@@ -396,7 +396,11 @@ void Lua::entry() {
                                          {"track", &sPlaybackTrack},
                                          {"position", &sPlaybackPosition},
                                      });
-    sLua->bridge().AddPropertyModule("queue", {
+    sLua->bridge().AddPropertyModule(
+        "queue",
+        {
+            {"next", [&](lua_State* s) { return QueueNext(s); }},
+            {"previous", [&](lua_State* s) { return QueuePrevious(s); }},
             {"position", &sQueuePosition},
             {"size", &sQueueSize},
             {"replay", &sQueueRepeat},
@@ -476,6 +480,16 @@ auto Lua::PushLuaScreen(lua_State* s) -> int {
   return 0;
 }
 
+auto Lua::QueueNext(lua_State*) -> int {
+  sServices->track_queue().next();
+  return 0;
+}
+
+auto Lua::QueuePrevious(lua_State*) -> int {
+  sServices->track_queue().previous();
+  return 0;
+}
+
 auto Lua::PopLuaScreen(lua_State* s) -> int {
   PopScreen();
   luavgl_set_root(s, sCurrentScreen->content());