Background playback w/ Foreground Service

[goto-bus-stop]

The things that the Service needs to do:

• Maintain websocket connection
  • Reconnect on network changes
  • Reconnect on other network failure
• Handle advance websocket messages
  • Update the player
  • Update the notification
• Cache websocket messages so they can be passed to Dart when the app is foregrounded
• Future: handle chat websocket messages only for mention notifications
• Handle upvoting and downvoting through the notification box
• Handle disconnecting through the notification box
  • This should quit the player and the service
  • The app should detect, when foregrounded, that it's no longer connected and navigate to the server list page

Ideally, the player should have a defined API so we can switch between NewPipe and Official™ YouTube™ at build time. Then the Official™ YouTube™ version could be published on the Play Store maybe. For SoundCloud we could use ExoPlayer, the HTTP API, and an API key.

[goto-bus-stop]

Some state should be maintained in the Java part for this to work, I think. chat history, users, and playback state, i think. Things like playlists and play history can be loaded again when the user re-enters the app.