require 'dotenv'
require 'json'
require 'open-uri'

Dotenv.load

class TumblrService
  TUMBLR_API_KEY = ENV["TUMBLR_API_KEY"]
  TUMBLR_API_SECRET = ENV["TUMBLR_API_SECRET"]
  TUMBLR_ACCESS_TOKEN = ENV["TUMBLR_ACCESS_TOKEN"]
  TUMBLR_ACCESS_TOKEN_SECRET = ENV["TUMBLR_ACCESS_TOKEN_SECRET"]
  TUMBLR_BLOG_URL = ENV["TUMBLR_BLOG_URL"]

  def initialize
    raise "TUMBLR_API_KEY is required" unless TUMBLR_API_KEY
    raise "TUMBLR_API_SECRET is required" unless TUMBLR_API_SECRET
    raise "TUMBLR_ACCESS_TOKEN is required" unless TUMBLR_ACCESS_TOKEN
    raise "TUMBLR_ACCESS_TOKEN_SECRET is required" unless TUMBLR_ACCESS_TOKEN_SECRET
    raise "TUMBLR_BLOG_URL is required" unless TUMBLR_BLOG_URL

    @tumblr = Tumblr::Client.new(
      :consumer_key => TUMBLR_API_KEY,
      :consumer_secret => TUMBLR_API_SECRET,
      :oauth_token => TUMBLR_ACCESS_TOKEN,
      :oauth_token_secret => TUMBLR_ACCESS_TOKEN_SECRET,
    )
  end

  def post_image(image_path)
    @tumblr.photo(TUMBLR_BLOG_URL, {:data => [image_path]})
  end
end

class YouTubeService
  YTDLP_PATH = `which yt-dlp`.chomp
  FFMPEG_PATH = `which ffmpeg`.chomp
  FFPROBE_PATH = `which ffprobe`.chomp
  VIDEO_PATH = "/tmp/video.mp4"
  FRAME_PATH = "/tmp/frame.png"
  PLAYLIST_ID = ENV["PLAYLIST_ID"]

  def initialize
    raise "PLAYLIST_ID is required" unless PLAYLIST_ID
    raise "Can't find youtube-dl" if YTDLP_PATH.empty?
    raise "Can't find ffprobe" if FFPROBE_PATH.empty?
    raise "Can't find ffmpeg" if FFMPEG_PATH.empty?
  end

  def fetch_random_frame_of_random_video
    download_random_video
    extract_frame
    delete_video

    FRAME_PATH
  end

  def download_random_video
    `#{YTDLP_PATH} --playlist-random --max-downloads 1 -o #{VIDEO_PATH} -f mp4 #{PLAYLIST_ID}`
  end

  def extract_frame
    random_second = rand(0..get_video_length)
    `#{FFMPEG_PATH} -v error -ss #{random_second} -i #{VIDEO_PATH} -frames 1 -y #{FRAME_PATH}`
  end

  def get_video_length
    `#{FFPROBE_PATH} -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 #{VIDEO_PATH}`.chomp.to_i
  end

  def delete_video
    `rm #{VIDEO_PATH}`
  end

  def delete_frame
    `rm #{FRAME_PATH}`
  end
end

youtube = YouTubeService.new
image_path = youtube.fetch_random_frame_of_random_video
tumblr = TumblrService.new
tumblr.post_image(image_path)
youtube.delete_frame