require "rest-client"
require "base64"
require "json"

class SpotifyClient
  SPOTIFY_REDIRECT_URI = "#{ENV['SPOTIFY_REDIRECT_URI']}/spotify_callback".freeze
  SCOPE = "user-read-recently-played".freeze

  BASE_URL = "https://api.spotify.com/v1/".freeze

  attr_reader :login

  def initialize(login = nil)
    @login = login
  end

  def load_since(load_since)
    params = {
      "limit" => "50"
    }
    params["after"] = load_since unless load_since.nil?
    get("me/player/recently-played", params)
  end

  def token_response_from_code(code)
    auth_code_authorize(code)
  end

  def auth_redirect_url
    "https://accounts.spotify.com/authorize?" \
    "response_type=code&" \
    "client_id=#{ENV['SPOTIFY_CLIENT_ID']}&" \
    "scope=#{SCOPE}&" \
    "redirect_uri=#{CGI.escape(SPOTIFY_REDIRECT_URI)}"
  end

  private

  def get(path, params = {})
    refresh_token!
    begin
      call(path, params)
    rescue RestClient::ExceptionWithResponse => e
      if e.response.code == 401
        Rails.logger.info("token expired, forcing refresh")
        refresh_token!(force: true)
        begin
          call(path, params)
        rescue RestClient::ExceptionWithResponse
          Rails.logger.info("token dead")
          LogLoadFailedWorker.perform_async(login.id)
        end
      else
        Rails.logger.error("SpotifyClient: #{e.message}")
        raise e
      end
    end
  end

  def call(path, params)
    headers = { "Authorization" => "Bearer #{login.credentials['access_token']}" }
    headers[:params] = params if params.present?
    JSON.parse RestClient.get("#{BASE_URL}#{path}", headers)
  end

  def refresh_token!(force: false)
    return unless login.about_to_expire? || force

    request_body = {
      'refresh_token': login.credentials["refresh_token"],
      'grant_type': "refresh_token"
    }

    begin
      auth_response = RestClient.post(
        "https://accounts.spotify.com/api/token",
        request_body,
        client_auth_headers
      )
      new_credentials = JSON.parse auth_response
      login.update_access_token!(new_credentials)
    rescue RestClient::ExceptionWithResponse => e
      login.update(dead_since: Time.new)
      raise e
    end
  end

  def client_auth_headers
    auth_plain = "#{ENV['SPOTIFY_CLIENT_ID']}:#{ENV['SPOTIFY_CLIENT_SECRET']}"
    auth_string = Base64.strict_encode64 auth_plain
    {
      'Authorization': "Basic #{auth_string}"
    }
  end

  def auth_code_authorize(code)
    request_body = {
      'code': code,
      'redirect_uri': SPOTIFY_REDIRECT_URI,
      'grant_type': "authorization_code"
    }
    begin
      auth_response = RestClient.post(
        "https://accounts.spotify.com/api/token",
        request_body,
        client_auth_headers
      )
    rescue RestClient::ExceptionWithResponse => e
      raise e
    end

    raise StandardError.new("Authorization failed", auth_response) unless auth_response.code == 200

    JSON.parse auth_response.body
  end
end