@startuml spotify

' visual style
hide circle

' straight lines
skinparam Linetype ortho
skinparam Nodesep 110
skinparam Ranksep 80

entity User {
    * id: <<Serial / UUID>>
    ---
    * first_name: Text
    * last_name: Text
    * email: Text
    * password: Text
    * birth_date: Timestamp
    * profile_picture: <<URL>>
}

entity Song {
    * id: <<Serial>>
    ---
    * name: Text
    * duration: Timestamp
    * release_date: Timestamp
    ' endpoint for streaming service 
    * streaming_address: <<URL>>
    cover_picture: <<URL>>
}

entity Album {
    * id: <<Serial>>
    ---
    * name: Text
    * release_date: Timestamp
    * description: Text
    * cover_picture: <<URL>>
}

entity Artist {
    * id: <<Serial / UUID>>
    ---
    * profile_picture: <<URL>>
    * cover_picture: <<URL>>
    * description: Text
    * verified: bool
}

entity Genre {
    * id: <<Serial>>
    ---
    * name: Text
    * description: Text
    * cover_picture: <<URL>>
}

entity Playlist {
    * id: <<Serial>>
    ---
    * cover_picture: <<URL>>
    * duration: Timestamp
}

' User has `0 to infinite` number of playlists. Playlist is always created by exactly one user (could be expanded to allow collaborative playlists).
User ||..o{ Playlist: user_playlists
' a user account can also be an artist -> only one per account
User ||..o| Artist: can_be_artist



' song belongs to an album. Song can only belong to one album (could be expanded so that one song can belong to more albums)
Album ||.o{ Song: has_songs
' album can belong to multiple genres
Album }o..o{ Genre: albums_have_genres



' artist has albums. Albums can only have one artist (could be expanded to allow features etc.)
Artist ||..o{ Album: has_albums



' song can be saved in a playlist
Playlist }o..o{ Song: playlists_have_songs


' even playlists can belong to certain genres -> spotify genre allows you to listen to playlists
Playlist }o..o{ Genre: playlists_have_genres

@enduml