module Scrivito
#
# This module provides CMS controller actions.
# Include it in controller you want to make able to deliver +Obj+s.
#
# @api public
#
# @see Scrivito::TestRequest#for_scrivito_obj
#
# @example
#   class PageCmsController < ApplicationController
#     include Scrivito::ControllerActions
#   end
#
module ControllerActions
  extend ActiveSupport::Concern

  included do
    before_filter :require_authenticated_editor, only: [
      :show_widget,
      :widget_details,
      :page_details,
    ]

    before_filter :load_object

    helper_method :scrivito_in_editable_view?
  end

  #
  # Default action.
  # Delivers files directly if +Obj+ is binary.
  # Otherwise the view is rendered.
  #
  # @api public
  #
  def index
    deliver_file if @obj.binary?
  end

  def show_widget
    widget = load_widget
    widget_tag = Scrivito::WidgetTag.new(view_context, widget, nil,
                                         params[:template_name], params[:inner_tag])
    render text: widget_tag.render, layout: false
  end

  def widget_details
    assert_dialog_layout
    widget = load_widget
    template_path = "#{widget.obj_class_name.underscore}/details"
    @scrivito_default_widget_template = :details
    render template_path, layout: 'scrivito_dialog', locals: {widget: widget}
  end

  def page_details
    assert_dialog_layout
    @scrivito_default_widget_template = :details
    render @obj.details_view_path, layout: 'scrivito_dialog'
  rescue ActionView::MissingTemplate
    render 'scrivito/page_details', layout: 'scrivito_dialog'
  end

  # How to handle widget errors in +production+.
  #
  # When an exception is raised from within a widget, the entire page is not available.
  # Often, this is the case in production if the developer has forgotten to handle specific
  # content scenarios such as empty date attributes, missing titles, unmanaged enum values, etc.
  # but also for simple coding mistakes during development.
  #
  # Override this method to prevent the entire page from being unavailable due to widget errors.
  #
  # The overridden method allows to:
  # * catch a widget error and replace it with an HTML placeholder.
  # * report a widget error to an external service like Honeybadger or Airbrake.
  #
  # This method is _not_ called if Rails is in the +development+ or +test+ environment.
  # In those environments, all widget errors are just raised.
  #
  # By default, this method just reraises the given error.
  #
  # @param widget [Scrivito::BasicWidget] the flawed widget
  # @param error [StandardError] the error that occurred
  # @raise [StandardError] if this method is not overridden, the +error+ passed to it is reraised.
  #
  # @example Notify external service about widget error and render an HTML placeholder:
  #   def on_scrivito_widget_error(widget, error)
  #     # Report error to external service (e.g. Honeybadger or Airbrake):
  #     Honeybadger.notify(error)
  #     notify_airbrake(error)
  #
  #     # Replace corrupted widget output with a placeholder:
  #     message = "Rendering #{widget.description_for_editor} failed with #{error.message}"
  #     return "<!--#{message}-->".html_safe if Rails.env.production?
  #     "<p>#{message}</p>".html_safe
  #   end
  # @api public
  def on_scrivito_widget_error(widget, error)
    raise error
  end

  #
  # Returns whether the GUI is in the +editable+ view.
  #
  # +scrivito_in_editable_view?+ is also a helper method.
  #
  # @api public
  # @return +true+ if the current visitor is an authenticated editor, the selected workspace is
  #   editable and the display mode is +editing+.
  # @return +false+ otherwise.
  #
  def scrivito_in_editable_view?
    editing_context.editable_display_mode?
  end

  #
  # Returns the current user.
  #
  # +scrivito_user+ is also a helper method.
  #
  # @api public
  # @return [Scrivito::User] if the {Scrivito::Configuration.editing_auth} callback returns an
  #   instance of {Scrivito::User}.
  # @return +nil+ otherwise.
  #
  def scrivito_user
    editing_context.editor
  end

  module ClassMethods
    #
    # This method indicates if this controller should be used automatically when an +Obj+ is
    # requested via the SDK's standard routes. It returns +true+ by default.
    #
    # Override it to return +false+ if you do want your controller to be excluded from +Obj+
    # dispatching.
    #
    # @api public
    # @see Obj#controller_name
    #
    def use_for_obj_dispatch?
      true
    end
  end

  private

  def require_authenticated_editor
    head(:forbidden) unless editing_context.authenticated_editor?
  end

  def editing_context
    EditingContextMiddleware.from_request(request)
  end

  delegate :comparison, to: :editing_context

  def load_object
    CmsEnv.new(request.env).load
    loaded_obj = request.env[CmsEnv::OBJ_ENV_KEY]
    raise loaded_obj if loaded_obj.is_a?(StandardError)
    @obj = loaded_obj
  end

  def load_widget
    widget = widget_from_current_revision || widget_from_base_revision
    raise ResourceNotFound, "Widget with ID #{params[:widget_id]} not found!" unless widget
    widget
  end

  def widget_from_current_revision
    @obj.widget_from_pool(params[:widget_id])
  end

  def widget_from_base_revision
    if comparison.active? # The "diff" mode.
      @obj.in_revision(editing_context.selected_workspace.base_revision)
        .widget_from_pool(params[:widget_id])
    end
  end

  #
  # Deliver a binary +Obj+ by redirecting to its {BasicObj#binary Obj#binary}'s url.
  # Will respond with 404 if the +Obj+ has no +blob+.
  #
  # @api public
  #
  def deliver_file
    if binary = @obj.binary
      url = BinaryRouting.new(request, scrivito_engine).resolved_binary_obj_url(@obj, binary)
      redirect_to CmsRouting.match_protocol(url, request)
    else
      render text: 'Empty Blob', status: 404
    end
  end

  def assert_dialog_layout
    view_context.lookup_context.find('layouts/scrivito_dialog')
  rescue ActionView::MissingTemplate
    raise %{
      Missing the Scrivito dialog layout!

      Scrivito requires a special view layout in order to render the details dialog.
      Normally the install generator places it in `app/views/layouts/scrivito_dialog.html.erb`.
      If upgrading Scrivito, please re-run the install generator: `rails g scrivito:install`.
    }
  end
end

end