#
# Copyright Michael Orlitzky
#
# http://michael.orlitzky.com/
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# http://www.fsf.org/licensing/licenses/gpl.html
#

# Needed for the default implementation of get_page_data.
require 'net/http'

# Necessary in a lot of subclasses; plus, we need it
# to parse the server name out of our URL.
require 'uri'

# Needed to download.. things.
require 'net/http'

# This class keeps track of all its subclasses
# We use this to loop through every "website" in an
# attempt to determine to which site a URL belongs.
class Website
 
  protected;
  
  @url = nil

  
  def self.inherited(subclass)
    if superclass.respond_to? :inherited
      superclass.inherited(subclass)
    end

    # Every time we're subclassed, add the new
    # subclass to our list of subclasses.
    @subclasses ||= []
    @subclasses << subclass
  end


  def server
    # Get the HTTP server portion of our URI
    uri = URI.parse(@url)
    return uri.host
  end


  
  def get_page_data(url)
    # A naive implementation that just grabs the
    # data from a page.
    uri = URI.parse(url)

    response = Net::HTTP.start(uri.host, uri.port) do |http|
      http.get(uri.request_uri)
    end

    return response.body
  end

  
  
  public;

  def initialize(url)
    @url = url
  end

  
  def self.create(url)
    # Factory method returning an instance of
    # the appropriate subclass.
    
    # Check the URL against each website's class.
    # The class will know whether or not the URL
    # "belongs" to its website.
    @subclasses.each do |w|
      if w.owns_url?(url)
        return w.new(url)
      end
    end

    # If nothing matched, we don't return an instance
    # of anything.
    return nil
  end


  # Abstract definition. Each subclass of Website
  # should support it on its own.
  def self.owns_url?(url)
    raise NotImplementedError
  end

  
  # Same here. Abstract.
  def get_video_url()
    raise NotImplementedError
  end

  
  # The website class should be responsible for determining the
  # video's filename. By default, we can take the last component
  # of the video URL, but in some cases, subclasses will want
  # to override this behavior.
  def get_video_filename()
    # Use whatever comes after the final front slash.    
    return get_video_url().split('/').pop()
  end
  
end