require 'nokogiri'
require 'set'

require 'esi_attribute_language'
require 'parse_user_agent'

require File.join(File.dirname(__FILE__), 'esi_for_rack', 'node')
require File.join(File.dirname(__FILE__), 'esi_for_rack', 'lookup')

class EsiForRack
  
  def initialize(app, lookup = nil)
    @app = app
    @lookup = lookup
  end
  
  def self.response_body_to_str(response_body)
    if response_body.respond_to? :to_str
      response_body.to_str
    elsif response_body.respond_to?(:each)
      body = ''
      response_body.each { |part|
        body << part.to_s
      }
      body
    else
      raise TypeError, "stringable or iterable required"
    end
  end
  
  def call(env)
    @lookup ||= [Lookup::PassThrough.new(@app, env), Lookup::Http.new(@app, env)]
    request = Rack::Request.new(env)
    result = @app.call(env)
    response = Rack::Response.new(result[2], result[0], result[1])

    if response['Content-Type'] =~ /text\/html/
      body = EsiForRack.response_body_to_str(result.last)
      
      user_agent_hash = {}
      begin
        user_agent = ParseUserAgent.new.parse(env['HTTP_USER_AGENT'] || '-')
        user_agent_hash['browser'] = case user_agent.browser
        when  'Firefox' then 'MOZILLA'
        when  'MSIE'    then 'MSIE'
        else;                'OTHER'
        end

        user_agent_hash['version'] = user_agent.browser_version_major

        user_agent_hash['os'] = case user_agent.ostype
        when  'Windows'   then 'WIN'
        when  'Macintosh' then 'MAC'
        else;                  'OTHER'
        end

      rescue
        # error parsing ua
      end
      
      binding = {
        :HTTP_ACCEPT_LANGUAGE => Set.new((env['HTTP_ACCEPT_LANGUAGE'] || '').split(',').map{|l| l.gsub(/q=[0-9]\.[0-9]{1,3}/, '').gsub(';','').strip}),
        :HTTP_COOKIE => request.cookies,
        :HTTP_HOST => request.host,
        :HTTP_REFERER => request.referer,
        :HTTP_USER_AGENT => user_agent_hash,
        :QUERY_STRING => request.GET
      }
      context = Node::Context.new(binding, @lookup)
      
      parsed_body = context.parse(body).to_s
      response.header['Content-Length'] = parsed_body.size.to_s
      
      [response.status, response.headers, [parsed_body]]
    else
      result
    end
    
  end
  
end