oldhaven/app/controllers/artist_controller.rb

require 'open-uri'
require 'musicbrainz'

class ArtistController < ApplicationController
  def data
    # Bad params
    if params[:name].nil? or params[:name].empty?
      return render json: { status: 'loading_failed' }
    end
    
    # Searching for artist
    artist_name = get_artist_name_from_query
    @artist = Artist.find_by_name(artist_name, include: {artist_links: {}, albums: {tracks: {}}})
    
    # Artist not found in DB
    unless @artist
      results = MusicBrainz::Artist.search(artist_name)
      if results.empty?
        return render json: { status: 'not_found' }
      end
      best_match = results[0][:name]
      if best_match != artist_name and (best_match.downcase == artist_name.downcase or best_match.downcase == 'the '+ artist_name.downcase)
        return render json: { status: 'corrected', correct_name: best_match }
      elsif results[0][:name] == artist_name
        queue_loading(artist_name, results[0][:mbid])
        @artist = { artist: @artist, albums: [] }
        @loading = true
        return render json: { status: 'loading', html: render_compact_partial(:page) }
      else
        @suggestions = results.take(5)
        return render json: { status: 'suggestions', html: render_compact_partial(:suggestions) }
      end
    end
    
    # Artist loading failed
    if @artist.status == 2
      return render json: { status: 'fail', html: render_compact_partial(:fail) }
    end
    
    render json: { status: @artist.status_str, artist: @artist, html: render_compact_partial(:page) }, include: {albums: {include: {tracks: {}}}}
  end
  
private

  def get_artist_name_from_query
    params[:name].gsub('%20', ' ').gsub('+', ' ').gsub('.html', '')
  end
  
  def queue_loading artist_name, mbid
    @artist = Artist.create( name: artist_name, mbid: mbid, status: 0 )
    Delayed::Job.enqueue(LoadArtistJob.new(artist_name))
  end
end