#! /usr/bin/env ruby
# usage:
# $ das_download.rb email password
# based on various gists from this thread https://gist.github.com/maca/1798070

require "mechanize"
require "nokogiri"
require "fileutils"

class DasDownloader
  attr_reader :agent, :email, :password

  def initialize(email, password)
    @agent = Mechanize.new
    @email, @password = email, password
  end

  def screencasts
    screencasts = []
    screencasts_metadata_html.each do |html|
      next unless (meta = html.at("h1.season_title"))

      season = meta.at("a").attr("name")

      html.search(".episode").each do |episode|
        #title = replace episode.at(".title").text.gsub("/", "-")
        title_node = Nokogiri::HTML.parse(episode.to_s).css('.title')
        title_node.css('.tag').remove
        title = replace title_node.text
        number = episode.at(".number").text.gsub("/", "-").rjust(3, "0")
        url = episode.at("a").attr("href")
        download_url = url + "/download"
        description = replace episode.at(".subtitle").text
        duration = episode.at(".duration").text

        screencasts << Screencast.new(season, title, number, description, duration, download_url)
      end
    end

    screencasts
  end

  def run
    screencasts.each do |screencast|
	  if screencast.season != "Classic season 1" && screencast.season != "Classic season 2"
	    puts "#{screencast.season}"
        download screencast
	  end
    end
  end

  private

  def replace(name)
    name.gsub!(":", " ")
    name.gsub!("/", " ")
    name.gsub!("\\", " ")
    name.gsub!("<", " ")
    name.gsub!(">", " ")
    name.gsub!("|", " ")
    name.gsub!("?", " ")
    name.gsub!("*", " ")
    name.gsub!("\"", " ")
    name.gsub!(/\s+/, ' ')
    name
  end

  def login
    agent.get "https://www.destroyallsoftware.com/screencasts/users/sign_in"

    if (form = agent.page.forms.first)
      form["user[email]"]    = email
      form["user[password]"] = password

      form.submit
      agent.pluggable_parser.default = Mechanize::Download
    end
  end

  def download(screencast)
    puts "Downloading #{screencast.season} - #{screencast.title}"

    FileUtils::mkdir_p(replace screencast.season)
    Dir.chdir(replace screencast.season) do
      title = replace "#{screencast.number} #{screencast.title}"
      FileUtils::mkdir_p(title)
      Dir.chdir(title) do
        File.open("metadata.txt", "w") do |metadata|
          metadata.puts "Number: #{screencast.number}"
          metadata.puts "Title: #{screencast.title}"
          metadata.puts "Description: #{screencast.description}"
          metadata.puts "Duration: #{screencast.duration}"
        end

        agent.get("https://destroyallsoftware.com#{screencast.url}").save("screencast.mp4")
      end
    end
  end

  def screencasts_metadata_html
    login

    agent.get "https://www.destroyallsoftware.com/screencasts/catalog"
    agent.page.search(".season").reverse
  end

  Screencast = Struct.new(:season, :title, :number, :description, :duration, :url)
end

email    = ARGV[0] or raise("Please provide the email address for your account")
password = ARGV[1] or raise("Please provide the password for your account")

DasDownloader.new(email, password).run