class GovukPublishingComponents::Presenters::RelatedNavigationHelper

def calculate_section_link_limit(links)
  links.length == MAX_SECTION_LENGTH + 1 ? MAX_SECTION_LENGTH + 1 : MAX_SECTION_LENGTH
end

def construct_section_heading(section_title)
  unless section_title == "related_items"
    I18n.t(
      "components.related_#{@context}_navigation." + section_title,
      default: [
        I18n.t("components.related_navigation.#{section_title}"),
        section_title.tr("_", " "),
      ],
    )
  end
end

def content_item_details_for(key)
  Array(@content_item.dig("details", key))
    .map { |link| { path: link["url"], text: link["title"], rel: "external" } }
end

def content_item_links_for(key, only: nil)
  links = Array(@content_item.dig("links", key))
  if key == "taxons"
    links = links.find_all { |link| link["phase"] == "live" }
  end
  if only.present?
    links = links.find_all { |link| link["document_type"] == only }
  end
  links.map do |link|
    {
      path: link["base_path"],
      text: link["title"],
      locale: link["locale"],
    }
  end
end

def detailed_guide?
  @content_item["document_type"] == "detailed_guide"
end

def initialize(options = {})
  @content_item = options.fetch(:content_item) { raise ArgumentError, "missing argument: content_item" }
  @context = options.fetch(:context, nil)
end

def related_contacts
  content_item_links_for("related", only: "contact")
end

def related_document_collections
  content_item_links_for("document_collections", only: "document_collection")
end

def related_external_links
  content_item_details_for("external_related_links")
end

def related_guides
  return [] unless detailed_guide?
  content_item_links_for("related_guides")
end

def related_items
  related_quick_links = content_item_details_for("quick_links")
  if related_quick_links.any?
    related_quick_links + related_mainstream_content
  else
    content_item_links_for("ordered_related_items") + related_mainstream_content
  end
end

def related_mainstream_content
  return [] unless detailed_guide?
  content_item_links_for("related_mainstream_content")
end

def related_navigation
  case @context.try(:to_sym)
  when :sidebar
    {
      "related_items" => related_items,
      "related_guides" => related_guides,
      "collections" => related_document_collections,
    }
  when :footer
    {
      "topics" => related_topics_or_taxons,
      "topical_events" => related_topical_events,
      "world_locations" => related_world_locations,
      "statistical_data_sets" => related_statistical_data_sets,
      "related_external_links" => related_external_links,
      "related_contacts" => related_contacts,
    }
  else
    {
      "related_items" => related_items,
      "related_guides" => related_guides,
      "collections" => related_document_collections,
      "topics" => related_topics_or_taxons,
      "topical_events" => related_topical_events,
      "world_locations" => related_world_locations,
      "statistical_data_sets" => related_statistical_data_sets,
      "related_external_links" => related_external_links,
      "related_contacts" => related_contacts,
    }
  end
end

def related_navigation?
  related_navigation.flat_map(&:last).any?
end

def related_statistical_data_sets
  content_item_links_for("related_statistical_data_sets", only: "statistical_data_set")
end

def related_taxons
  @related_taxons ||= content_item_links_for("taxons", only: "taxon")
end

def related_topical_events
  content_item_links_for("topical_events", only: "topical_event")
end

def related_topics
  @related_topics ||= begin
    mainstream_browse_page_links = content_item_links_for("mainstream_browse_pages", only: "mainstream_browse_page")
    topic_links = content_item_links_for("topics", only: "topic")
    return topic_links if topic_links.present? && mainstream_browse_page_links.empty?
    mainstream_browse_page_links + topic_links.find_all do |topic_link|
      mainstream_browse_page_links.none? do |mainstream_browse_page_link|
        mainstream_browse_page_link[:text] == topic_link[:text]
      end
    end
  end
end

def related_topics_or_taxons
  return related_topics if related_topics.any?
  return related_taxons if related_taxons.any?
  []
end

def related_world_locations
  content_item_links_for("world_locations")
    .map do |link|
      slug = WORLD_LOCATION_SPECIAL_CASES[link[:text]] || link[:text].parameterize
      link.merge(path: "/world/#{slug}/news")
    end
end

def remaining_link_count(links)
  links.length - MAX_SECTION_LENGTH
end

def section_css_class(css_class, section_title, link: {}, link_is_inline: false)
  css_classes = [css_class]
  css_classes << "#{css_class}--#{@context}" unless @context.nil?
  css_classes << "#{css_class}--inline" if link_is_inline
  unless DEFINED_SECTIONS.include?(section_title) || link.fetch(:finder, false)
    css_classes << " #{css_class}--other"
  end
  css_classes.join(" ")
end

def section_data_track_count(section_title)
  String(@context || "sidebar") + String(section_title).camelcase
end

def section_heading_level
  @context == :footer ? "h2" : "h3"
end