require 'fileutils'
require 'ostruct'
require 'mechanize'
require 'uri'

module Scrapers
  
  module RubyTapas

    module_function

    # Save the post and attachments from an episode of RubyTapas
    # in a directory determined from the episode title.
    #
    # Example:
    #  episode url: "https://rubytapas.dpdcart.com/subscriber/post?id=443"
    #  title: "177 Aliasing | RubyTapas"
    #  subdirectory: /177-aliasing
    #
    # Parameters:
    #
    # * *url* - url of the episode to download
    # * *user* - username used to log into dpdcart
    # * *pw* - password used with username
    # * *dest* - destination directory to put episode subdirectory
    #
    def scrape(url=nil, user=nil, pw=nil, dest=".")
      raise "Must give user and password for RubyTapas downloads" if user.to_s.empty? or pw.to_s.empty?
      dest = File.realdirpath(dest)
      raise "Destination #{dest} must be a writeable directory" unless File.directory?(dest) and File.writable?(dest)

      Mechanize.start do |m|

        tapas = OpenStruct.new

        m = self.login(m, url, user, pw)

        m.current_page.tap do |page|
          tapas.title = page.title.strip
          tapas.episode_dir = File.join(dest,tapas.title.split("|").first.strip.downcase.gsub(%r{[^[:alnum:][:space:]]},' ').gsub(%r{[[:space:]]+},'-'))
          tapas.attachments = page.links_with(:href => %r{\bdownload\b})
          puts "Fetching and saving #{tapas.title} into #{tapas.episode_dir}"
          FileUtils.mkdir(tapas.episode_dir)
          Dir.chdir(tapas.episode_dir) do |dir|
            tapas.attachments.each do |att|
              puts "fetching #{att.text}"
              file = att.click
              puts "saving #{file.filename}"
              file.save
            end
          end
        end
        
        tapas
        
      end
    end
    
    # retrieve a list of URLs for shows from the showlist
    def self.showlist(showlist_url, user=nil, pw=nil)
      raise "Must give showlist url, user, and password" if showlist_url.to_s.empty? || user.to_s.empty? || pw.to_s.empty?

      Mechanize.start do |m|
        m = self.login(m, showlist_url, user, pw)
        links = m.current_page.links_with(:text => "Read More")
        s = URI.parse(showlist_url)
        s.path = ''
        links.map{|l| "#{s}#{l.href}" }
      end

      
    end

    def self.login(m, url, user, pw)
      # First time, we will get redirected to the login page
      m.get url
      m.current_page.form.field_with(:name => "username").value = user
      m.current_page.form.field_with(:name => "password").value = pw
      m.current_page.form.submit

      # Second time, we should land on episode page
      m.get url
      raise "Not where I expected. #{m.current_page.uri} is not #{url}" unless m.current_page.uri != url
      m
    end
    
  end
end