SoTW: Save to Spotify

[kellenGary]

Summary

Fix the Song of the Week (SoTW) "Save to Spotify" functionality — playlist creation/updating fails because the OAuth scopes granted during user sign-up are insufficient.

Background

• When a user tries to save a SoTW playlist to their Spotify account, the operation fails silently or errors out.
• The root cause appears to be that the client scopes requested during Spotify OAuth sign-up do not include the permissions needed to create and modify playlists.
• The Spotify Web API requires specific scopes (playlist-modify-public, playlist-modify-private) for playlist write operations.

Scope

Backend (C# API)

• Review the Spotify OAuth configuration to identify which scopes are currently being requested.
• Add the necessary playlist-write scopes (playlist-modify-public and/or playlist-modify-private) to the OAuth flow.
• Verify the playlist creation and update endpoints handle errors gracefully and return meaningful messages.

Frontend (React Native)

• Ensure the user is prompted to re-authorize if their existing token lacks the required scopes.
• Display appropriate error/success feedback when saving a playlist.

Spotify API Reference

• Consult the Spotify Authorization Scopes documentation to confirm the exact scopes needed for playlist operations.

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Definition of Done

• Scopes updated: The OAuth flow requests playlist-modify-public and/or playlist-modify-private scopes.
• Playlist creation works: A new user can successfully save a SoTW playlist to their Spotify account after signing up.
• Playlist update works: An existing SoTW playlist can be updated with new tracks on subsequent weeks.
• Re-auth handling: Existing users with old tokens are prompted to re-authorize to gain the new scopes.
• Error handling: If playlist save fails, the user sees a clear error message (not a silent failure).
• Success feedback: On successful save, the user sees confirmation that the playlist was created/updated.
• Build passes: Both the C# API and the frontend compile without errors.
• Manual verification: Tested end-to-end with a fresh Spotify account — sign up → generate SoTW → save to Spotify → verify playlist appears in Spotify.