spotify web setup is done

app/controllers/application_controller.rb

@@ -1,4 +1,16 @@
 class ApplicationController < ActionController::Base
   # Only allow modern browsers supporting webp images, web push, badges, import maps, CSS nesting, and CSS :has.
   allow_browser versions: :modern
+
+  before_action :check_spotify_login
+
+  private
+
+  def check_spotify_login
+    if user_signed_in? && current_user.logins.where(platform: "spotify").none?
+      unless request.path == spotify_connect_path || request.path == spotify_path || request.path == spotify_callback_path || devise_controller?
+        redirect_to spotify_path
+      end
+    end
+  end
 end

app/controllers/spotify_controller.rb

@@ -0,0 +1,57 @@
+class SpotifyController < ApplicationController
+  before_action :authenticate_user!
+
+  def index
+    # If already connected, redirect to dashboard
+    redirect_to statistics_path if current_user.logins.exists?(platform: "spotify")
+  end
+
+  def connect
+    # If user already has a login, redirect to statistics dashboard
+    return redirect_to statistics_path if current_user.logins.exists?(platform: "spotify")
+    client_id = ENV["SPOTIFY_CLIENT_ID"]
+    redirect_uri = SpotifyClient::SPOTIFY_REDIRECT_URI
+    scope = SpotifyClient::SCOPE
+    state = SecureRandom.hex(16)
+    session[:spotify_auth_state] = state
+    auth_url = "https://accounts.spotify.com/authorize?" + {
+      client_id: client_id,
+      response_type: "code",
+      redirect_uri: redirect_uri,
+      scope: scope,
+      state: state
+    }.to_query
+    redirect_to auth_url, allow_other_host: true
+  end
+
+  def callback
+    if params[:state] != session.delete(:spotify_auth_state)
+      return redirect_to spotify_path, alert: "Invalid state parameter. Please try again."
+    end
+    if params[:code].present?
+      if handle_spotify_callback(params[:code])
+        redirect_to statistics_path, notice: "Spotify authorization successful."
+      else
+        redirect_to spotify_path, alert: "Spotify authorization failed. Please try again."
+      end
+    else
+      redirect_to spotify_path, alert: "Spotify authorization failed."
+    end
+  end
+
+  private
+
+  def handle_spotify_callback(code)
+    begin
+      token_response = SpotifyClient.new(current_user).token_response_from_code(code)
+      Login.find_or_create_for_response!(current_user, token_response)
+      true
+    rescue RestClient::Exception, JSON::ParserError => e
+      Rails.logger.error("Spotify callback error: #{e.class} - #{e.message}")
+      false
+    rescue StandardError => e
+      Rails.logger.error("Unexpected Spotify callback error: #{e.class} - #{e.message}")
+      false
+    end
+  end
+end