require 'page_by_page/version'
require 'page_by_page/url'
require 'nokogiri'
require 'open-uri'

class PageByPage

  class << self
    def fetch &block
      pbp = self.new &block
      pbp.fetch
    end
  end

  def initialize &block
    instance_eval &block
  end

  def url tmpl
    @url = Url.new tmpl
  end

  def selector sl
    @selector = sl
  end

  def fetch
    items, all_items = [nil], []
    until items.empty?
      doc = parse @url.next
      items = doc.css @selector
      all_items << items
    end
    all_items.flatten
  end

  private

  def parse url
    Nokogiri::HTML open url
  end

end