require 'govuk_navigation_helpers/services'
require 'govuk_navigation_helpers/configuration'

module GovukNavigationHelpers
  class RelatedNavigationSidebar
    def initialize(content_item)
      @content_item = ContentItem.new content_item
    end

    def related_navigation_sidebar
      {
        related_items: related_items,
        collections: related_collections,
        statistical_data_sets: related_statistical_data_sets,
        topics: related_topics,
        topical_events: related_topical_events,
        policies: related_policies,
        publishers: related_organisations,
        world_locations: related_world_locations,
        worldwide_organisations: related_worldwide_organisations,
        other: [related_external_links, related_contacts]
      }
    end

  private

    def build_links_for_sidebar(collection, path_key = "base_path", additional_attr = {})
      collection.map do |link|
        {
          text: link["title"],
          path: link[path_key]
        }.merge(additional_attr)
      end
    end

    def world_location_base_path(title)
      "/world/#{parameterise(title)}/news"
    end

    def related_items
      quick_links = build_links_for_sidebar(@content_item.quick_links, "url")

      quick_links.any? ? quick_links : build_links_for_sidebar(@content_item.related_ordered_items)
    end

    def related_organisations
      build_links_for_sidebar(@content_item.related_organisations)
    end

    def related_world_locations
      locations = @content_item.related_world_locations
      locations.map! { |link| link.merge("base_path" => world_location_base_path(link["title"])) }
      build_links_for_sidebar(locations)
    end

    def related_worldwide_organisations
      build_links_for_sidebar(@content_item.related_worldwide_organisations)
    end

    def related_collections
      build_links_for_sidebar(@content_item.related_collections)
    end

    def related_policies
      build_links_for_sidebar(@content_item.related_policies)
    end

    def related_statistical_data_sets
      build_links_for_sidebar(@content_item.related_statistical_data_sets)
    end

    def related_topics
      topics = build_links_for_sidebar(@content_item.related_topics)
      topics << related_mainstream_topic << related_mainstream_parent_topic
      topics.compact
    end

    def related_topical_events
      build_links_for_sidebar(@content_item.related_topical_events)
    end

    def related_contacts
      return [] unless @content_item.related_other_contacts.any?
      [
        title: "Other contacts",
        links: build_links_for_sidebar(@content_item.related_other_contacts).map
      ]
    end

    def related_external_links
      return [] unless @content_item.external_links.any?
      [
        title: "Elsewhere on the web",
        links: build_links_for_sidebar(@content_item.external_links, "url", rel: 'external')
      ]
    end

    def related_mainstream_topic
      return unless grouped.tagged_to_same_mainstream_browse_page.any?
      { text: @content_item.parent.title, path: @content_item.parent.base_path }
    end

    def related_mainstream_parent_topic
      return unless grouped.parents_tagged_to_same_mainstream_browse_page.any?
      { text: @content_item.parent.parent.title, path: @content_item.parent.parent.base_path }
    end

    def parameterise(str, sep = "-")
      parameterised_str = str.gsub(/[^\w\-]+/, sep)
      unless sep.nil? || sep.empty?
        re_sep = Regexp.escape(sep)
        # No more than one of the separator in a row.
        parameterised_str.gsub!(/#{re_sep}{2,}/, sep)
        # Remove leading/trailing separator.
        parameterised_str.gsub!(/^#{re_sep}|#{re_sep}$/, '')
      end
      parameterised_str.downcase
    end

    def grouped
      @grouped ||= GroupedRelatedLinks.new(@content_item)
    end
  end
end