require 'volt/utils/ejson'

module Volt
  class Page
    attr_reader :url, :params, :page, :routes, :events

    def initialize(volt_app)
      @volt_app = volt_app
      # Run the code to setup the page
      @page          = PageRoot.new

      @url         = URL.new
      @params      = @url.params
      @url_tracker = UrlTracker.new(self)
      @templates   = {}

      @events = DocumentEvents.new

      if RUBY_PLATFORM == 'opal'
        if Volt.in_browser?
          # Setup escape binding for console
          `
            $(document).keyup(function(e) {
              if (e.keyCode == 27) {
                Opal.gvars.page.$launch_console();
              }
            });

            $(document).on('click', 'a', function(event) {
              return Opal.gvars.page.$link_clicked($(this).attr('href'), event);
            });
          `
        end
      end

      # Initialize tasks so we can get the reload message
      tasks if Volt.env.development?

      if Volt.in_browser?
        channel.on('reconnected') do
          @page._reconnected = true

          `setTimeout(function() {`
          @page._reconnected = false
          `}, 2000);`
        end
      end
    end

    def flash
      @flash ||= FlashRoot.new({}, persistor: Persistors::Flash)
    end

    def store
      @store ||= StoreRoot.new({}, persistor: Persistors::StoreFactory.new(tasks))
    end

    def local_store
      @local_store ||= LocalStoreRoot.new({}, persistor: Persistors::LocalStore)
    end

    def cookies
      @cookies ||= CookiesRoot.new({}, persistor: Persistors::Cookies)
    end

    def tasks
      @tasks ||= Tasks.new(self)
    end

    def link_clicked(url = '', event = nil)
      # Skip when href == ''
      return false if url.blank?

      # Normalize url
      # Benchmark.bm(1) do
      if @url.parse(url)
        if event
          # Handled new url
          `event.stopPropagation();`
        end

        # Clear the flash
        flash.clear

        # return false to stop the event propigation
        return false
      end
      # end

      # Not stopping, process link normally
      true
    end

    # We provide a binding_name, so we can bind events on the document
    def binding_name
      'page'
    end

    def launch_console
      puts 'Launch Console'
    end

    def channel
      @channel ||= begin
        if Volt.client?
          Channel.new
        else
          ChannelStub.new
        end
      end
    end

    attr_reader :events

    def add_template(name, template, bindings)
      # First template gets priority.  The backend will load templates in order so
      # that local templates come in before gems (so they can be overridden).
      #
      # TODO: Currently this means we will send templates to the client that will
      # not get used because they are being overridden.  Need to detect that and
      # not send them.
      unless @templates[name]
        @templates[name] = { 'html' => template, 'bindings' => bindings }
      end
    end

    # On the server, we can delay loading the views until they are actually requeted.  This
    # sets up an instance variable to call to load.
    attr_writer :template_loader

    def templates
      if @template_loader
        # Load the templates
        @template_loader.call
        @template_loader = nil
      end

      @templates
    end

    def add_routes(&block)
      @routes ||= Routes.new
      @routes.define(&block)
      @url.router = @routes
    end

    def start
      # Setup to render template
      `$('body').html('<!-- $CONTENT --><!-- $/CONTENT -->');`

      load_stored_page

      # Do the initial url params parse
      @url_tracker.url_updated(true)

      main_controller = Main::MainController.new(@volt_app)

      # Setup main page template
      TemplateRenderer.new(@volt_app, DomTarget.new, main_controller, 'CONTENT', 'main/main/main/body')

      # Setup title reactive template
      @title_template = StringTemplateRenderer.new(@volt_app, main_controller, 'main/main/main/title')

      # Watch for changes to the title template
      proc do
        title = @title_template.html.gsub(/\n/, ' ')
        `document.title = title;`
      end.watch!
    end

    # When the page is reloaded from the backend, we store the $page.page, so we
    # can reload the page in the exact same state.  Speeds up development.
    def load_stored_page
      if Volt.client?
        if `sessionStorage`
          page_obj_str = nil

          `page_obj_str = sessionStorage.getItem('___page');`
          `if (page_obj_str) {`
          `sessionStorage.removeItem('___page');`

          EJSON.parse(page_obj_str).each_pair do |key, value|
            page.send(:"_#{key}=", value)
          end
          `}`
        end
      end
    rescue => e
      Volt.logger.error("Unable to restore: #{e.inspect}")
    end
  end
end