feat(api): POST /api/listening-sessions

[Rend1027]

• Define Sequelize model/controller logic (if not already)
• Create backend route: POST /api/listening-sessions
• Accept payload from the front end:
  {
  "spotifyTrackId": "123abc",
  "title": "Song Name",
  "artist": "Artist Name",
  "preview_url": "...",
  "image_url": "...",
  "lat": 40.7128,
  "lng": -74.0060,
  "timestamp": "optional" // if not sent, use current date
  }

In controller/ also known as the Logic of the endpoint:

• Use userId from req.user.id (via JWT)
• Check if the song already exists in Songs table (via spotifyTrackId)
  - If not, create it
• Save ListeningSession with user_id, song_id, lat, lng, and timestamp

This creates a new entry in our ListeningSessions table that ties:

• the user
• the song
• the location
• the time

The app triggers this request after the user logs in, and you’ve collected:

• their geolocation
• their currently playing or recently played track

Remember we have 2 separate tables:
Songs — a master list of unique songs (one row per track)
ListeningSessions — every time a user listens to a track
This is why we always check if the song exist in our Song Table .. we want to avoid having duplicates.

Tip:

1. Get the user’s ID
   2.Check if the song exists
2. If not, create the song
3. Create the listening session
4. send payload back to the front end :
   {
   "message": "Listening session saved",
   "song": {
   "title": "City of Gods",
   "artist": "Fivio Foreign",
   "preview_url": "...",
   "image_url": "..."
   },
   "session": {
   "lat": 40.7527,
   "lng": -73.9772,
   "timestamp": "2025-07-31T00:00:00.000Z"
   }
   }