I'd like this Spotify integration to work one of two ways:
a) ability to drag songs from the Spotify client into MusicBee, creating an entry in the library we can then add to playlists along with local files
b) ability to browse our 'Liked' songs list from Spotify directly in MusicBee client, and then again add those songs along with local files into playlists
Let me preface this by saying that I have no intention of ever implementing these suggestions - it would be an enormous undertaking and I don't think they're particularly useful.
For fun, I thought of a couple of ways you could potentially accomplish this. I settled on one which is the least difficult considering the
many obstacles you'd run into when trying to develop this.
For suggestion A:
1. Steven would have to allow web shortcuts to be stored in MusicBee (they are created when you drag songs out of Spotify).
2. The Spotify API would be used to translate the track ID in the shortcuts into metadata.
3. When a shortcut is clicked, it would have to launch a Spotify-approved web browser (probably Chromium-based) that you have authenticated.
4. Pausing, playing, skipping, etc. are an entirely separate issue to tackle...
5. Once a track is completed, it would have to close the browser and send a callback to MusicBee to continue to the next track.
For suggestion B:
1. Steven would have to allow web shortcuts to be stored in MusicBee.
2. The Spotify API would be used to sync your Spotify Liked Songs playlist to a playlist in MusicBee by creating shortcuts and populating the appropriate metadata.