# -*- encoding: utf-8 -*-
module StreamWrapper
  
  # Modfies and injects buy_basket blob information into stream.
  # 1. Inserts attributes from buy_basket blob into the buy_basket observation.
  # 2. Adds a buy_item observation for each item in the basket.
  class OrderBlobSplitter

    def initialize (input)
      input = StringIO.new(input) if input.class == String  # Used for testing.
      @stream = input
      @buy_item_lines = []
    end

    def gets
      if @buy_item_lines.size > 0
        return @buy_item_lines.shift
      end
      
      line = @stream.gets
      if line && line.include?("&o=buy_basket&")
        extract_buy_items(line)
        line = reformat_buy_basket(line)
      end
      line
    end

    def eof?
      @stream.eof? 
    end

  private
  
    # Blob format:
    # RW:T|2142||1079.00|215.80|0.00|strömstad||Sweden|
    # RW:I|2142|MATAW09 Wanni L|Overall (98)||1079.00|1|
    #
    # See also http://www.google.com/support/googleanalytics/bin/answer.py?hl=en&answer=55528

    def reformat_buy_basket(line)
      blob = extract_order_blob(line)
      order_blob = blob.match(/^RW:T\|(([^\|]*\|[^\|]*){7})\|/)[1]
      values = order_blob.split("|")
      attributes = {}
      [:order_id, :affiliation, :total, :tax, :shipping, :city, :state, :country].each_with_index do |name, index|
        attributes[name] = values[index]
      end
      insert_user_attributes(line, attributes)
    rescue
      line
    end
    
    def extract_buy_items(line)
      blob = extract_order_blob(line)
      blob.scan(/RW:I\|(([^\|]*\|[^\|]*){5})\|/) do |item_blob|
        values = item_blob[0].split("|")
        attributes = {}
        [:order_id, :sku, :title, :category, :current_price, :quantity].each_with_index do |name, index|
          attributes[name] = values[index]
        end
        @buy_item_lines << insert_user_attributes(line, attributes, :replace).gsub("&o=buy_basket", "&o=buy_item")
      end
    end
    
    def extract_order_blob(line)
      CGI::unescape(line.match(/_order_blob=([^&]+)&/)[1]) rescue ""
    end
    
    # 81.225.100.141 - - [23/Nov/2009:06:45:23 +0100] "GET /log.gif?_order_blob=RW%3AT%7C2142%7C%7C1079.00%7C215.80%7C0.00%7Cstr%C3%B6mstad%7C%7CSweden%7C%20%0ARW%3AI%7C2142%7CMATAW09%20Wanni%20L%7COverall%20(98)%7C%7C1079.00%7C1%7C&_order_nr=002142&a=Mozilla%2F4.0%20(compatible%3B%20MSIE%208.0%3B%20Windows%20NT%205.1%3B%20Trident%2F4.0%3B%20Mozilla%2F4.0%20(compatible%3B%20MSIE%206.0%3B%20Windows%20NT%205.1%3B%20SV1)%20%3B%20.NET%20CLR%202.0.50727%3B%20.NET%20CLR%203.0.4506.2152%3B%20.NET%20CLR%203.5.30729)&aid=jetshop&l=sv&n=microsoft%20internet%20explorer&o=buy_basket&p=win32&s=1024x600&sid=www.pixiekids.se&t=Unika%20barnkl%C3%A4der%20%26%20babykl%C3%A4der%20hos%20Pixiekids%20%E2%8E%AE%200-10%20%C3%A5r&u=https%3A%2F%2Fwww.pixiekids.se%2FOrderDetailsConfirmed.aspx&uid=1258954551578656003&x=87544&z=-60& HTTP/1.1" 200 35 "https://www.pixiekids.se/OrderDetailsConfirmed.aspx" "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1) ; .NET CLR 2.0.50727; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)"
    def insert_user_attributes(line, attributes, method = :merge)
      encoded_attributes = []
      attributes_regexp = /\?(.*?)&(?!_)/
      # Add existing attributes from line.
      unless method == :replace
        encoded_attributes = line.match(attributes_regexp)[1].split("&").map { |pair| pair.split("=") }
      end
      # Add in attributes from method argument.
      attributes.each do |key, value|
        next if value.nil? || value == ""
        encoded_key = CGI.escape("_#{key}")
        encoded_value = CGI.escape(value)
        encoded_attributes.reject!{ |k, v| k == encoded_key }
        encoded_attributes << [encoded_key, encoded_value]
      end
      # Reconstruct the user attributes part of the line.
      attributes_string = encoded_attributes.sort.map do |key, value|
        "#{key}=#{value}&"
      end.join
      # Replace the old user attributes in the line with the new ones.
      line.sub(attributes_regexp, "?#{attributes_string}")
    end
    
  end
end