module RailsConnector

  # This module contains helpers that can be used to reference images and other assets stored in the CMS.
  #
  # @api public
  module CmsAssetHelper

    # Calculates an HTML image tag for an image stored in the CMS.
    #
    # @note There are two different signatures of this method: the first one generates an HTML image tag with no
    #   inplace editing possible, the second one generated an HTML image tag for inplace editing.
    #
    # @overload cms_image_tag target, tag_options={}
    #   @note If you do not specify an HTML +alt+ attribute, the helper method will use +target+'s +display_title+.
    #   Calculates HTML image tag (no inplace editing possible).
    #
    #   @param [Obj, Link] target Target containing image stored in CMS.
    #   @param [Hash] tag_options Additional HTML attributes for the tag.
    #
    #   @example
    #     cms_image_tag @target
    #     cms_image_tag @target, alt: 'Interesting picture', class: 'my_image'
    #
    # @overload cms_image_tag obj, linklist, tag_options={}, editing_options={}
    #   @note If you do not specify an HTML +alt+ attribute, the helper method will use +obj+'s +display_title+.
    #   Calculates HTML image tag for inplace editing.
    #
    #   @param [Obj] obj Obj with an attribute of type {LinkList}.
    #   @param [String, Symbol] linklist Name of {LinkList} attribute, which contains the image.
    #   @param [Hash] tag_options Additional HTML attributes for the tag.
    #
    #   @param [Hash] editing_options Additional options for inplace editing.
    #   @option editing_options [String] :placeholder ('/assets/rails_connector/image_placeholder.png') URL or path to image to be displayed if target is missing.
    #
    #   @example
    #     cms_image_tag @obj, :my_linklist
    #     cms_image_tag @obj, :my_linklist, alt: 'Interesting picture', class: 'my_image'
    #     cms_image_tag @obj, :my_linklist, {}, placeholder: image_path('my_placeholder.png')
    #     cms_image_tag @obj, :my_linklist, {class: 'my_image'}, placeholder: 'http://placehold.it/350x150'
    #
    # @return [String] HTML image tag
    # @api public
    def cms_image_tag(*args)
      if args.second.nil? || args.second.is_a?(Hash)
        target = args.first
        if target.is_a?(LinkList)
          ActiveSupport::Deprecation.warn(%{
            Calling "cms_image_tag" with a "LinkList" is not allowed anymore.
            Please use following syntax instead: cms_image_tag(@obj, :linklist).
          })
        end

        tag_options = args.second || {}
        tag_options.symbolize_keys!
        tag_options[:src] = cms_path(target)
        tag_options[:alt] ||= display_title(target)
      else
        obj = args.first
        attribute_name = args.second
        target = obj[attribute_name]
        tag_options = args.third || {}
        editing_options = args.fourth || {}

        tag_options.symbolize_keys!
        editing_options.symbolize_keys!

        tag_options[:src] ||= begin
          target_path = cms_path(target)
          if target_path == RailsConnector::DefaultCmsRoutingHelper::LINK_TO_EMPTY_LINKLIST
            editing_options[:placeholder] || image_path('rails_connector/image_placeholder.png')
          else
            target_path
          end
        end

        if inplace_editing_allowed?
          tag_options.merge!(
            'data-ip-resource-source-obj-id' => obj.id,
            'data-ip-resource-source-field-name' => attribute_name
          )
        end

        tag_options.reverse_merge!(alt: display_title(target))
      end

      tag('img', tag_options)
    end

    private

    def display_title(target)
      if target.respond_to?(:display_title)
        return target.display_title
      elsif target.respond_to?(:first) && target.first.respond_to?(:display_title)
        return target.first.display_title
      end
    end

  end
end