module Iloveptt

# File lib/iloveptt.rb, line 6
def self.download(url)
  page_uri = URI.parse(url)

  # TODO: valid url
  # http://rubular.com/
  # raise ArgumentError.new("Unrecognized URL: #{url}")

  agent = Mechanize.new

  page = agent.get(page_uri)

  title = page.title.split(" - ")[0]
  post_id = page.uri.path.split("/").last.gsub('.html', '')

  puts "Parsing #{title}"

  # TODO: check file extension via regex
  image_urls = page.links.map(&:to_s).select{ |url| %(jpg png).include? url.split('.').last }

  target_folder_path = File.expand_path("~/Pictures/iloveptt/#{post_id} - #{title}")

  FileUtils.mkdir_p(target_folder_path) unless Dir.exists?(target_folder_path)

  image_urls.each do |image_url|
    image = agent.get(image_url)

    filename = File.expand_path(File.basename(image.uri.path), target_folder_path)
    File.delete(filename) if File.exists?(filename)
    image.save(filename)
  end

  puts "Done!"
end