require 'wovnrb/store'
require 'wovnrb/headers'
require 'wovnrb/lang'
require 'nokogumbo'
#require 'dom'
require 'json'

require 'wovnrb/railtie' if defined?(Rails)

module Wovnrb

  STORE = Store.new
  
  class Interceptor
    def initialize(app)
      @app = app
    end

    def call(env)
      unless STORE.valid_settings?
        return @app.call(env)
      end
      @env = env
      headers = Headers.new(env, STORE.settings)
      # redirect if the path is set to the default language (for SEO purposes)
      if (headers.path_lang == STORE.settings['default_lang'])
        redirect_headers = headers.redirect(STORE.settings['default_lang'])
        return [307, redirect_headers, ['']]
      end
      lang = headers.lang

      # pass to application
      status, res_headers, body = @app.call(headers.request_out)

      if res_headers["Content-Type"] =~ /html/ && !body[0].nil?

        values = STORE.get_values(headers.redis_url)
        url = {
                :protocol => headers.protocol, 
                :host => headers.host, 
                :pathname => headers.pathname
              }
        body = switch_lang(body, values, url, lang, headers) unless status.to_s =~ /^1|302/

        content_length = 0
        body.each { |b| content_length += b.respond_to?(:bytesize) ? b.bytesize : 0 }
        res_headers["Content-Length"] = content_length.to_s

        body.close if body.respond_to?(:close)
      end

      headers.out(res_headers)
      [status, res_headers, body]
      #[status, res_headers, d.transform()]
    end


    def switch_lang(body, values, url, lang=STORE.settings['default_lang'], headers)
      text_index = values['text_vals'] || {}
      src_index = values['img_vals'] || {}
      img_src_prefix = values['img_src_prefix'] || ''
      string_index = {}
      body.map! do |b|
        d = Nokogiri::HTML5(b)
        d.encoding = "UTF-8"
        # swap text
        d.xpath('//text()').each do |node|
          node_text = node.content.strip
# shouldn't need size check, but for now...
          if text_index[node_text] && text_index[node_text][lang] && text_index[node_text][lang].size > 0
            node.content = node.content.gsub(/^(\s*)[\S\s]*(\s*)$/, '\1' + text_index[node_text][lang][0]['data'] + '\2')
          end
        end
        # swap meta tag values
        d.xpath('//meta').select{ |t|
          (t.get_attribute('name') || t.get_attribute('property') || '') =~ /^(description|keywords|og:title|og:description)$/
        }.each do |node|
          node_content = node.get_attribute('content').strip
# shouldn't need size check, but for now...
          if text_index[node_content] && text_index[node_content][lang] && text_index[node_content][lang].size > 0
            node.set_attribute('content', node_content.gsub(/^(\s*)[\S\s]*(\s*)$/, '\1' + text_index[node_content][lang][0]['data'] + '\2'))
          end
        end
        # swap img srcs
        d.xpath('//img').each do |node|
          # use regular expressions to support case insensitivity (right?)
          if node.to_html =~ /src=['"][^'"]*['"]/i
            src = node.to_html.match(/src=['"]([^'"]*)['"]/i)[1]
# THIS SRC CORRECTION DOES NOT HANDLE ONE IMPORTANT CASE
# 1) "../path/with/ellipse"
            # if this is not an absolute src
            if src !~ /:\/\//
              # if this is a path with a leading slash
              if src =~ /^\//
                src = "#{url[:protocol]}://#{url[:host]}#{src}"
              else
                src = "#{url[:protocol]}://#{url[:host]}#{url[:path]}#{src}"
              end
            end
          
# shouldn't need size check, but for now...
            if src_index[src] && src_index[src][lang] && src_index[src][lang].size > 0
              node.attribute('src').value = "#{img_src_prefix}#{src_index[src][lang][0]['data']}"
            end
          end
        end

        # REMOVE WIDGET
        d.xpath('//script').each do |script_node|
          if script_node['src'] && script_node['src'].include?('//j.wovn.io/')
            script_node.remove
          end
        end

        # PARENT NODE FOR INSERTS
        parent_node = d.at_css('head') || d.at_css('body') || d.at_css('html')

        # INSERT BACKEND WIDGET
        insert_node = Nokogiri::XML::Node.new('script', d)
        insert_node['src'] = '//j.wovn.io/0'
        insert_node['data-wovnio'] = "key=#{STORE.settings['user_token']}&backend=true&currentLang=#{lang}&defaultLang=#{STORE.settings['default_lang']}&urlPattern=#{STORE.settings['url_pattern']}"
        # do this so that there will be a closing tag (better compatibility with browsers)
        insert_node.content = ' '
        if parent_node.children.size > 0
          parent_node.children.first.add_previous_sibling(insert_node)
        else
          parent_node.add_child(insert_node)
        end

        
        # INSERT LANGUAGE METALINKS
        published_langs = get_langs(values)
        published_langs.each do |l|
          insert_node = Nokogiri::XML::Node.new('link', d)
          insert_node['rel'] = 'alternate'
          insert_node['hreflang'] = l
          insert_node['href'] = headers.redirect_location(l)
          parent_node.add_child(insert_node)
        end

        # set lang property on HTML tag
        if d.at_css('html') || d.at_css('HTML')
          (d.at_css('html') || d.at_css('HTML')).set_attribute('lang', lang)
        end

        output = d.to_html.gsub(/href="([^"]*)"/) {|m| "href=\"#{URI.decode($1)}\""}
        output
      end
      body
    end

    # this clearly needs to be refactored. I'm thinking maybe a Value service? (STORE.values.get_langs)
    def get_langs(values)
      langs = Set.new
      (values['text_vals'] || {}).merge(values['img_vals'] || {}).each do |key, index|
        index.each do |l, val|
            langs.add(l)
        end
      end
      langs
    end

  end

end