…bums

- Implemented new QueueService for handling most of the queueing logic
- Connected QueueService to MusicPlayerBackgroundTask for accessing the just_audio and audio_service queues
- Forwarded playback events from just_audio to QueueService to keep track of current item
- added new PlaybackList class for storing queue items + list meta info
- display PlaybackList info on player screen

- Refactored `QueueService` with the proper state variables and functions
- Linear & shuffled playback now working (for starting a new list, toggling doesn't work yet)
- Adding to queue works
- Manually skipping back and forth works
- Skips initiated by the player also update the internal queues of the QueueService

- there's still a bug if the player skips to the next track by itself: if 'loop all' was enabled previously but then disabled, the player will still loop once
- for more info see TODO at queue_service.dart:445

- needed to replace the concatenating audio source, because the player's index cannot be modified externally
- this results in backwards loops not being gapless, oh well...
- also fixed skipping backwards when 'loop one' is enabled (resets current track and adds entry to history)

- properly remove, prepend, and append AudioSources from/to the ConcatenatingAudioSource

- convert Streams to BehaviorSubjects
- show current track and queue (needs fixing)

- allows efficient and flexible combination of multiple lists and elements into a single scrolling view

- can skip to track in both recent track and the regular queue by tapping on them

- some inconsistencies still happen, but it mostly works

- only thing missing is disabling shuffling and keeping the right index

- fixed adjustedQueueIndex being using the track index instead of the array index
- fixed adjustedQueueIndex being based on shuffledIndices when shuffle disabled

…n first item

- allows skipping using the QueueList again

- proper reordering support (between lists!)
- current track is fixed
- lists can't be dragged anymore
- previous tracks collapsed by default

- add songs to next up (prepend and append)
- reorder songs
- show correct source

- added new screen showing the history (click a track starts an instant mix)
- added new service class for managing history and playback reporting

- fixes adding tracks to next up if the current track isn't the first track in the queue
- if the track was added to Next Up while shuffle was disabled, next up will stay in place when shuffle is toggled on and off
  - if shuffle was enabled while adding the track, toggling shuffle off will clear Next Up

- adding tracks to Next Up works when shuffled
- adding tracks to (end of) queue working when shuffled
- Next Up and end of queue stay in place when turning off shuffle
- toggling shuffle doesn't affect Next Up but will shuffle end of queue (only when turning shuffle *on*)
- adding to Next Up and end of queue also works when shuffle is disabled

…vice

…nt streambuilders

- implemented separate widgets for different queues
- reordering only possible within queues
- updated design to be closer to the mockup

…rewrite

what is *wrong* with just_audio?! shuffling the playlist on load? 👀

- doesn't work for all sources yet
- artist/album mixes will navigate to the first artists/album

- still needs a proper design and improved implementation

- try to update the actual QueueItem wherever possible to be robust against rebuilds
- added a callback to `FavouriteButton` to support updating e.g. the QueueItems in response to a toggle
- the favorite buttons on the player screen and in the queue list are now synced

- changes aren't limited to the queue list

- design tweaks
- tried to limit flickering when changing queue
- working with flutter 3.13.5, dart 3.1.2

- more robust with less race conditions
- can detect looping a single track

- has worked really well in my testing, with no pauses at all when losing reception for a few minutes
- this could increase data usage if the Next Up queue is used a lot (frequent changes to next tracks)
  - @jmshrv definitely add a disclaimer to the release notes!