Lua API improvements and fixes

Co-authored-by: jacqueline <me@jacqueline.id.au>

luals-stubs/backstack.lua

@@ -17,4 +17,8 @@ function backstack.push(screen) end
 --- there are no other screens in the stack.
 function backstack.pop() end
 
+--- Sets a new root screen, replacing any existing screens
+--- @param screen screen The new root screen
+function backstack.reset(screen) end
+
 return backstack

luals-stubs/bluetooth.lua

@@ -5,8 +5,17 @@
 --- @class bluetooth
 --- @field enabled Property Whether or not the Bluetooth stack is currently enabled. This property is writeable, and can be used to enable or disable Bluetooth.
 --- @field connected Property Whether or not there is an active connection to another Bluetooth device.
---- @field paired_device Property The device that is currently paired. The bluetooth stack will automatically connected to this device if possible.
---- @field devices Property Devices nearby that have been discovered.
+--- @field connecting Property Whether or not we are currently connecting to the paired device.
+--- @field discovering Property Whether or not we are actively scanning for new devices.
+--- @field paired_device Property The device that is currently paired. The bluetooth stack will automatically connect to this device if possible.
+--- @field discovered_devices Property Devices nearby that have been discovered.
+--- @field known_devices Property Devices that have previously been paired.
 local bluetooth = {}
 
+--- Enables Bluetooth, this is the same as bluetooth.enabled:set(true)
+function bluetooth.enable() end
+
+--- Disables Bluetooth, this is the same as bluetooth.enabled:set(false)
+function bluetooth.disable() end
+
 return bluetooth

luals-stubs/playback.lua

@@ -8,4 +8,9 @@
 --- @field position Property The current playback position within the current track, in seconds.
 local playback = {}
 
+--- Returns whether or not this file can be played (i.e. is this an audio track) 
+--- @param filepath string
+--- @return boolean
+function playback.is_playable(filepath) end
+
 return playback

luals-stubs/queue.lua

@@ -13,10 +13,10 @@
 --- @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 = {}
 
---- Adds the given track or database iterator to the end of the queue. Database
+--- Adds the given track, database iterator, or file to the end of the queue. Database
 --- iterators passed to this method will be unnested and expanded into the track
 --- ids they contain.
---- @param val TrackId|Iterator
+--- @param val TrackId|Iterator|string
 function queue.add(val) end
 
 --- Opens a playlist file from a filepath

src/tangara/audio/track_queue.cpp

@@ -236,6 +236,21 @@ auto TrackQueue::next() -> void {
   next(Reason::kExplicitUpdate);
 }
 
+auto TrackQueue::currentPosition(size_t position) -> bool {
+  {
+    const std::shared_lock<std::shared_mutex> lock(mutex_);
+    if (position >= totalSize()) {
+      return false;
+    }
+    goTo(position);
+  }
+
+  // If we're explicitly setting the position, we want to treat it as though 
+  // the current track has changed, even if the position was the same
+  notifyChanged(true, Reason::kExplicitUpdate);
+  return true;
+}
+
 auto TrackQueue::goTo(size_t position) -> void {
   position_ = position;
   if (opened_playlist_) {

src/tangara/audio/track_queue.hpp

@@ -73,6 +73,7 @@ class TrackQueue {
   auto current() const -> TrackItem;
 
   auto currentPosition() const -> size_t;
+  auto currentPosition(size_t position) -> bool;
   auto totalSize() const -> size_t;
   auto open() -> bool;
   auto openPlaylist(const std::string& playlist_file, bool notify = true)

src/tangara/ui/ui_fsm.cpp

@@ -201,7 +201,14 @@ lua::Property UiState::sPlaybackPosition{
       return true;
     }};
 
-lua::Property UiState::sQueuePosition{0};
+lua::Property UiState::sQueuePosition{0, [](const lua::LuaValue& val){
+                                      if (!std::holds_alternative<int>(val)) {
+                                        return false;
+                                      }
+                                      int new_val = std::get<int>(val);
+                                      // val-1 because Lua uses 1-based indexing
+                                      return sServices->track_queue().currentPosition(new_val-1);
+                                    }};
 lua::Property UiState::sQueueSize{0};
 lua::Property UiState::sQueueRepeat{false, [](const lua::LuaValue& val) {
                                       if (!std::holds_alternative<bool>(val)) {
@@ -610,6 +617,16 @@ void Lua::entry() {
                          {"paired_device", &sBluetoothPairedDevice},
                          {"discovered_devices", &sBluetoothDiscoveredDevices},
                          {"known_devices", &sBluetoothKnownDevices},
+                         {"enable", 
+                            [&](lua_State* s) {
+                              sBluetoothEnabled.set(true);
+                              return 0;
+                         }},
+                         {"disable", 
+                            [&](lua_State* s) {
+                              sBluetoothEnabled.set(false);
+                              return 0;
+                         }},
                      });
     registry.AddPropertyModule(
         "playback",