# Youtube Converter for Ruby
# Description: Downloads a file from a YT URL transcodes them to MP3 or OGG and
# places it into a choosen folder
# Module: Downloader
# Work: It downloads a *.mp4 file from Youtube, then extracts audio to *.m4a
# Class Documentation:
# http://www.rubydoc.info/github/saigkill/youtube_dlhelper/Downloader
#
# Copyright (C) 2013-2017  Sascha Manns <Sascha.Manns@mailbox.org>


# Dependencies
require 'youtube-dl.rb'
require 'rainbow/ext/string'
require 'fileutils'

# Module for all Downloading things
module Downloader
  # Accessing the url with get(url) via youtube-dl.rb
  # @param [String] url Is the given URL to the Youtube file
  def self.get(url)
    puts 'Downloading file...'.colour(:green)
    # Thanks for the gist https://gist.github.com/sapslaj/edb51218357fa33b6c4c
    video = YoutubeDL.download(url)
    video.filename # => "Adele - Hello-YQHsXMglC9A.f137.mp4"

    video_with_title = YoutubeDL.download(url, extract_audio: true, audio_format: 'best', audio_quality: 0, output: '%(title)s.%(ext)s')
    video_with_title.filename # => "Adele - Hello.mp4"

    title = YoutubeDL::Runner.new(url, get_title: true).run
    title # => "Adele - Hello"
    puts 'Downloading done...'.colour(:green)
    filename = video_with_title.filename

    rename(filename)
  end

  # rubocop:disable Metrics/AbcSize
  # This method smells of :reek:TooManyStatements
  # This method smells of :reek:UncommunicativeVariableName
  # Method for renaming the orig file with blanks to underscores
  # @param [String] url Is the given URL to the Youtube file
  # @return [String] filenamenew The fixed filename with underscores
  def self.rename(filenameorig)
    extn = File.extname filenameorig # .mp4
    filename = File.basename filenameorig, extn
    ext = file_exist_ogg_m4a(filename)
    # @note Replacing blanks with underscrores and delete non standard chars in
    # filename
    filenamenew0 = filename.gsub(/ /, '_')
    pattern = /[a-zA-Z0-9\-\s\_]/
    filenamenew = filenamenew0.split(//).keep_if do |chr|
      chr =~ pattern
    end.join
    puts 'Renaming the downloaded file'.colour(:green)
    FileUtils.mv("#{filename}.#{ext}", "#{filenamenew}.#{ext}")
    [filenamenew, filename]
  end

  # It checks what old file are available
  # @param [String] title
  # @return ext
  def self.file_exist_ogg_m4a(filename)
    if File.exist?("#{filename}.ogg")
      ext = 'ogg'
    elsif File.exist?("#{filename}.m4a")
      ext = 'm4a'
    elsif File.exist?("#{filename}.webm")
      ext = 'webm'
    end
    return ext
  end
end