require 'discordrb'
require 'uri'
require 'optparse'
require 'shellwords'

options = {}
OptionParser.new do |opt|
  opt.on("-t", "--token DISCORD_BOT_TOKEN") {|o| options[:bot_token] = o}
  opt.on("-c", "--channel CHANNEL_ID") {|o| options[:channel_id] = Integer(o)}
end.parse!

if options.length == 0
  puts "Need to specifiy token and channel"
  exit
end

puts "creating spool and tracks directories"
system("mkdir -p spool")
system("mkdir -p tracks")

mpd = false
if File.exists?("/usr/bin/mpd")
  if !File.exists?("/usr/bin/mpc")
    puts "Bailing since mpd exists but not mpc (which is needed to control mpd)"
    exit
  end
  puts "starting mpd if not already running"
  system("systemctl start mpd") unless `ps aux | grep mpd` != ""
  system("mpc clear")
  system("mpc add /")
  mpd = true
end

bot = Discordrb::Bot.new token: options[:bot_token]
bot.message(in: options[:channel_id],contains: "youtube.com") do |event|
  event.respond("got message")
  urls = URI.extract(event.content)
  if urls != ""
    puts "Found #{urls}; downloading"
    urls.each do |url|
      res = `youtube-dl --ignore-errors --output \"spool/%(title)s.%(ext)s\" --extract-audio --audio-format mp3 #{url}`
      if res 
        puts "Downloaded #{url}"
      else
        puts "error downloading #{url}"
      end
    end
    if mpd
      puts "telling mpd to refresh"
      new_songs = Dir["spool/*.mp3"]
      system("mv spool/*.mp3 tracks/")
      system("mpc update")
      new_songs.each do |song|
        s = song.split("/")[1]
        res = system("mpc add #{Shellwords.shellescape(s)}")
        if res
          puts "added #{s} to mpd"
        else 
          puts "error adding #{s} to mpd"
        end
      end
    end
  end

end

bot.run