Requirements for playlists from Atlas perspective

Some quick analysis of playlists design and features we would like to implement for Atlas:

Playlist input
Data that will be provided when creating a playlist:

• Associated channel
• Title
• Description
• Visibility (public/unlisted, same as for videos)
• List of videos that should be included (all from a single channel) in a specific order
• Optional custom thumbnail - this is a bit more complex. We want the user to optionally provide an image that will be a thumbnail for the playlist. However, if the thumbnail is not provided, we would like the thumbnail of the playlist to be automatically populated with the thumbnail of the first video in the playlist. This would be a dynamic relationship, so if I change the first video and there's no custom thumbnail, the automatic thumbnail should be updated.

Playlist actions:
Actions that can be taken on a playlist:

• Change any of the details (excluding associated channel) mentioned above
• Change order of the videos
• Add new videos
• Remove videos
• Delete a playlist

Computed data:
Additional data we would like to query from a playlist but is not explicitly defined in the input:

• Counter of public uncensored videos inside the playlist
• Full duration of playlist playback (sum of duration of all the public uncensored videos in the playlists)

Open questions:

• One thing I'm not sure how we could handle is adding a video to a playlist as part of publishing the video. So you publish a video and select playlist(s) to add it to right away. Any ideas on how this could be handled?