https://blog.seekwell.io/endless-spotify-playlist

RADIO - A SPOTIFY PYTHON PROJECT
Create a RADIO themed playlist based on the idea of an 'endless' or 'infinite' playlist.
Remeniscent of listening to Luxembourg and Pirate stations back in the day.

OVERVIEW
After listening to tracks from the RADIO playlist, the app will delete the ones that have bèen played, 
(using Spotify's recently played API), and add new ones automatically, from those 'up next' with tracks
recycled from a feeder playlist.
The FEED is just one big playlist consisting of your 'Liked' or favorite tunes.

FEED acts like a large conveyor belt of tracks that you only see a small section of at any one time in RADIO.
FEED recycles the tracks after they have been played.

Every 15 mins, a scheduler takes the played tracks, removes them from the RADIO playlist and tops it up with
the next selection from the FEED archive. (max 50).

Tracks are shuffled, before being recycled, so they never come around in exactly the same order.
With a very large FEED, it could be months before the same track appears again. 
The system ensures that ALL the tracks get played just once, before repeating the cycle.

If you listen to other tracks or playlists, when you return to the RADIO playlist, you should be able to simply
resume where you left off.

10-01-2020