How to add existing songs to a music library Rails 4 - ruby-on-rails

Question

What I'm trying to do is add songs that artists have already uploaded to a user library (I have already set up my app so that artists can upload songs). Also, I have set up my code so that an empty user library is created after a user signs up (using the after_create Active Record Callback).
To be more clear, I would like for the user to be able to add songs they see within the site to their library.
However, this is escaping me. I am familiar with CRUD, and have an idea how I would create a library and add existing songs to it, but I am not quite sure how I could add a song to a user library by clicking a button/link saying "Add Song To Library" which would be next to a song, and having it add to the user's existing empty library.
My existing code is below.
User.rb:
class User < ActiveRecord::Base
# Include default devise modules. Others available are:
# :confirmable, :lockable, :timeoutable and :omniauthable
devise :database_authenticatable, :registerable,
:recoverable, :rememberable, :trackable, :validatable
belongs_to :meta, polymorphic: true
before_create :create_empty_profile
after_create :create_empty_library #may not be the best way to do it ¯\_(ツ)_/¯
acts_as_messageable
has_many :playlists
has_many :user_friendships, dependent: :destroy
has_many :friends, -> { where(user_friendships: { state: 'accepted'}) }, through: :user_friendships
has_many :pending_user_friendships, -> { where ({ state: 'pending' }) }, class_name: 'UserFriendship', foreign_key: :user_id
has_many :pending_friends, through: :pending_user_friendships, source: :friend
has_many :chat_rooms, dependent: :destroy
has_many :chat_messages, dependent: :destroy
has_many :votes, dependent: :destroy
mount_uploader :profile_pic, ProfilePicUploader
def mailboxer_name
self.name
end
def mailboxer_email(object)
self.email
end
def admin?
role == 'admin'
end
def moderator?
role == 'moderator'
end
def create_empty_profile
if is_artist?
profile = ArtistProfile.new
else
profile = UserProfile.new
end
profile.save(validate: false)
self.meta_id = profile.id
self.meta_type = profile.class.name
end
def create_empty_library
library = Library.new
library.user_id = self.id
library.save(validate: false)
end
end
Library.rb:
class Library < ActiveRecord::Base
belongs_to :user
has_many :library_songs
has_many :songs, through: :library_songs
has_many :library_albums
has_many :albums, through: :library_albums
end
library_song.rb
class LibrarySong < ActiveRecord::Base
belongs_to :library
belongs_to :song
end
library_album.rb
class LibraryAlbum < ActiveRecord::Base
belongs_to :library
belongs_to :album
end
libraries_controller.rb
class LibrariesController < ApplicationController
def index
#libraries = Library.all
end
def show
#library = Library.find(params[:id])
end
end
I was able to create playlists and add songs to them using the form/controller below.
playlists/new.html.erb:
<h1>New Playlist</h1>
<%= form_for(#playlist) do |f| %>
<%= f.text_field :name %>
<% Song.all.each do |song| -%>
<div>
<%= check_box_tag :song_ids, song.id, false, :name => 'playlist[song_ids][]', id: "song-#{song.id}" %>
<%= song.name %>
</div>
<% end %>
<%= f.submit %>
<% end %>
playlists_controller.rb:
class PlaylistsController < ApplicationController
def index
#playlists = Playlist.all
end
def show
#playlist = Playlist.find(params[:id])
end
def new
#playlist = Playlist.new
end
def create
#playlist = Playlist.create(playlist_params)
redirect_to #playlist
end
private
def playlist_params
params.require(:playlist).permit(:name, song_ids: [])
end
end
However, the main issue is that in the form above, the playlist is being created along with the existing songs. In this case, I would need to add existing songs to an existing library that is empty.
Any ideas, guys? This would be very helpful. I would be happy to upload any code needed.

Answer 1

It looks to me like you don't actually have has_many :libraries set in your user model. Judging by your Library model, I think this was what you had intended. You should really just create the 'new' models before you save the User model. You could use something similar to this and do it all in one action.
class User < ActiveRecord::Base
def self.build_full_user(params, songs)
# Assign all normal attributes here
new_user = User.new
new_user.name = params[:name]
# If you want to assign new songs, just make a new Library model and associate them.
new_library = Library.new
# Build the song models if you haven't found/created or passed them in already.
new_songs = Songs.build_songs_from_list(songs)
new_library.songs << new_songs
new_user.libraries << new_library
# You can do the save check here or up one level if you'd like.
return new_user
end
end