#!/usr/bin/env ruby
# gem install mechanize
require 'mechanize'

abort "Usage:\n\tradiojavan.rb \"https://www.radiojavan.com/playlists/playlist/mp3/02596ef9986a\" output_txt" if ARGV.size < 2

playlist_url = ARGV[0]
output_file = ARGV[1]
HOST = 'https://www.radiojavan.com'

agent = Mechanize.new
playlist_url = "#{playlist_url}"
puts '-> Getting playlist page'
playlist_page = agent.get(playlist_url)
songs_page_links = playlist_page.search(".//ul[@class='listView']/li/a/@href").map(&:to_s)
puts "-> Found \"#{songs_page_links.size}\" songs there!"

download_links = []
pages_with_no_download_link = []

songs_page_links.each do |link|
  begin
    page = agent.get(HOST + link)
    puts "-> Got page \"#{page.title}\""
    script = page.search(".//script").map(&:to_s)[9]
    if script.match(/mp3-256/)
      file_name = script.split("\n")[2].scan(/\'.+\'/)[0].delete_suffix("'")
      file_name[0] = ''
      download_links.push "https://host2.rj-mw1.com/media/" + file_name + ".mp3"
    end
  rescue NoMethodError
    puts "-> No chance for \"#{page.title}\"  :("
    pages_with_no_download_link << page.title
    next
  end
end

File.open(output_file, 'w') { |f| f.puts download_links  }
puts
puts "## Extracted \"#{download_links.size}\" links and saved them into file \"#{output_file}\""
puts "## Download them with this command: aria2c -i ./#{output_file}"
puts
puts "## There wasn't any download link provided for following songs:"
pages_with_no_download_link.each do |title|
  puts "\t- #{title}"
end