Spotify.cql.models.rb

module AlbumArtist
  extend ActiveSupport::Concern
  included do

    validates :album_id, :presence => true
    validates :artist_id, :presence => true
  end
end

module FollowedPlaylist
  extend ActiveSupport::Concern
  included do
    # Followed Playlist involves Playlist
    belongs_to :playlist, :foreign_key => :playlist_id

    validates :user_id, :presence => true
  end
end

module Following
  extend ActiveSupport::Concern
  included do

    validates :follower_user_id, :presence => true
    validates :user_id, :presence => true
  end
end

module Performance
  extend ActiveSupport::Concern
  included do
    # Performance involves Song
    belongs_to :song, :foreign_key => :song_id

    validates :artist_id, :presence => true
  end
end

module Playlist
  extend ActiveSupport::Concern
  included do
    self.primary_key = 'playlist_id'

    # Playlist Sharing involves Secret Playlist
    has_many :playlist_sharings, :class_name => 'PlaylistSharing', :foreign_key => :secret_playlist_id, :dependent => :destroy

    # Playlist Member involves Playlist
    has_many :playlist_members, :class_name => 'PlaylistMember', :foreign_key => :playlist_id, :dependent => :destroy
    has_many :songs, :through => :playlist_members

    # Playlist Collaboration involves Collaborative Playlist
    has_many :playlist_collaborations, :class_name => 'PlaylistCollaboration', :foreign_key => :collaborative_playlist_id, :dependent => :destroy

    # Followed Playlist involves Playlist
    has_many :followed_playlists, :class_name => 'FollowedPlaylist', :foreign_key => :playlist_id, :dependent => :destroy

    validates :playlist_id, :presence => true
  end
end

module PlaylistCollaboration
  extend ActiveSupport::Concern
  included do
    # Playlist Collaboration involves Collaborative Playlist
    belongs_to :collaborative_playlist, :class_name => 'Playlist', :foreign_key => :collaborative_playlist_id

    validates :user_id, :presence => true
  end
end

module PlaylistMember
  extend ActiveSupport::Concern
  included do
    # Playlist Member involves Playlist
    belongs_to :playlist, :foreign_key => :playlist_id

    # Playlist Member involves Song
    belongs_to :song, :foreign_key => :song_id

  end
end

module PlaylistSharing
  extend ActiveSupport::Concern
  included do
    # Playlist Sharing involves Secret Playlist
    belongs_to :secret_playlist, :class_name => 'Playlist', :foreign_key => :secret_playlist_id

    validates :shared_with_user_id, :presence => true
  end
end

module Song
  extend ActiveSupport::Concern
  included do
    self.primary_key = 'song_id'

    # Performance involves Song
    has_many :performances, :class_name => 'Performance', :foreign_key => :song_id, :dependent => :destroy

    # Playlist Member involves Song
    has_many :playlist_members, :class_name => 'PlaylistMember', :foreign_key => :song_id, :dependent => :destroy
    has_many :playlists, :through => :playlist_members

    validates :song_id, :presence => true
  end
end