lyrics.rb

require 'rest-client'
require 'nokogiri'
require 'genius'
require 'similar_text'

class LyricsNotFound < StandardError; end

class LyricsFinder
  # change this constant if you want to increase or decrease the percentage
  # of similarity between the artist entered by the user and the artist
  # found on genius.com
  PERCENTAGE_OF_SIMILARITY = 80

  def initialize(api_key)
    Genius.access_token = api_key
  end

  def lyrics(track_name, track_artist)
    # beautify the song name removing the featuring in order to be easily
    # searchable on genius.com

    track_name.gsub!(/\((.*?)\)/, '')
    track_artist.gsub!(/\((.*?)\)/, '')

    track_name.gsub!(/.((ft\.|feat).*?)$/mi, '')
    track_artist.gsub!(/.((ft\.|feat).*?)$/mi, '')

    songs = Genius::Song.search("#{track_artist} #{track_name}")
    song_found = songs.first

    # if first method returns nil or song artist found is not similar by 80%
    # to the artist entered by the user then lyrics is not found

    if song_found.nil? ||
       (song_found.resource['primary_artist']['name'].downcase.similar(track_artist.downcase) < PERCENTAGE_OF_SIMILARITY)
      raise LyricsNotFound, "Lyrics not found for #{track_name}"
    end

    # download html content from the genius.com website and parse the div
    # lyrics downloading only the text removing extra tags

    html_content = RestClient.get(song_found.url)

    doc = Nokogiri::HTML::Document.parse(html_content)
    div = doc.at_css('div[data-lyrics-container=true]')
    div.css('br').each do |node|
      node.replace(Nokogiri::XML::Text.new("\n", div))
    end

    div.text
  end
end

class Lyrics < AbsPlugin
  def command
    /^\/lyrics$/
  end

  def show_usage
    bot.api.send_message(chat_id: message.chat.id, text: 'get lyrics from genius.com with /lyrics')
  end

  def examples
    [
      { command: '/lyrics', description: 'search for a lyrics of a song' }
    ]
  end

  def do_stuff(match_results)
    # find our more on how to get a Genius Access Token on: https://genius.com/api-clients
    lyrics_finder = LyricsFinder.new('ENTER YOUR GENIUS Client Access Token HERE!!!')
    track = { artist: '', name: '' }

    kb = Telegram::Bot::Types::ReplyKeyboardRemove.new(remove_keyboard: true)

    bot.api.send_message(chat_id: message.chat.id, text: 'what\'s the name of the song? 🎵')
    track[:name] = read_buffer
    bot.api.send_message(chat_id: message.chat.id, text: 'what\'s the name of the artst? 🎤')
    track[:artist] = read_buffer

    lyrics = lyrics_finder.lyrics(track[:name], track[:artist])
    bot.api.send_message(chat_id: message.chat.id, text: lyrics, reply_markup: kb)
  rescue LyricsNotFound
    bot.api.send_message(chat_id: message.chat.id, text: 'lyrics not found on genius.com', reply_markup: kb)
  rescue Genius::AuthenticationError
    bot.api.send_message(chat_id: message.chat.id, text: 'error occurred while using genius.com API', reply_markup: kb)
  end
end