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

def sanity_check_video(url)
  if !url.include?("youtube")
    return false
  end
  video = VideoInfo.new(url)
  title = video.title
  title.slice! " - YouTube Music"
  if video.duration > 1200
    puts "skipping #{url} since it's over 20 minutes"
    return false
  elsif File.exists?("tracks/#{title}.mp3") || File.exists?("spool/#{title}.mp3") 
    puts "#{url} already downloaded, not downloading again"
    return false
  end
  return true
end



def parse_songs_from_string(message)
  urls = URI.extract(message)
  if urls.length != 0
    puts "Found #{urls}; downloading"
    urls.each do |url|
      if sanity_check_video(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
    end
  end
  nil
end

def update_mpd()
      new_songs = Dir["spool/*.mp3"]
      if new_songs.length <= 0
	      return true
      end
      puts "telling mpd to refresh"
      `mv spool/*.mp3 tracks/`
      `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

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"
`mkdir -p spool`
`"mkdir -p tracks`

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"
  `systemctl start mpd` unless `ps aux | grep mpd` != ""
  `mpc clear`
  `mpc add /`
  `mpc shuffle`
  `mpc repeat`
end

bot = Discordrb::Commands::CommandBot.new token: options[:bot_token], prefix: '!radio '

bot.command :start do |event|
  `mpc play`
  event.respond("starting radio")
end

bot.command :stop do |event|
  `mpc stop`
  event.respond("stoping radio")
end

bot.command :reload do |event|
  event.respond("reloading queue")
  `mpc stop`
  `mpc clear`
  `mpc update`
  `mpc add /`
  event.respond("queue reloaded")
  nil
end

bot.command :pause do |event|
  event.respond("pausing playback")
  `mpc toggle`
  nil
end

bot.command :skip do |event|
  event.respond("skipping")
  `mpc next`
  nil
end

bot.command :shuffle do |event|
  `mpc shuffle`
  event.respond("shuffled queue")
  nil
end

bot.command :initialize do |event|
  event.respond("loading last 50 messages from channel")
  channel  = bot.channel(options[:channel_id])
  messages = channel.history(50)
  messages.each do |msg|
    parse_songs_from_string(msg.content)
  end
  update_mpd()
  event.respond("done loading")
end


bot.message(in: options[:channel_id],contains: "youtube.com") do |event|
  parse_songs_from_string(event.content)
  update_mpd()
end

bot.run