# frozen_string_literal: true

class WikiDirectory
  include ActiveModel::Validations

  attr_accessor :slug, :entries

  validates :slug, presence: true
  alias_method :to_param, :slug
  class << self
    # Groups a list of wiki pages into a nested collection of WikiPage and WikiDirectory objects,
    # preserving the order of the passed pages.
    #
    # Returns an array with all entries for the toplevel directory.
    #
    # @param [Array<WikiPage>] pages
    # @return [Array<WikiPage, WikiDirectory>]
    #
    def group_pages(pages)
      # Build a hash to map paths to created WikiDirectory objects,
      # and recursively create them for each level of the path.
      # For the toplevel directory we use '' as path, as that's what WikiPage#directory returns.
      directories = Hash.new do |_, path|
        directories[path] = new(path).tap do |directory|
          if path.present?
            parent = File.dirname(path)
            parent = '' if parent == '.'
            directories[parent].entries << directory
            directories[parent].entries.delete_if do |item|
              item.is_a?(WikiPage) && item.slug.casecmp?(directory.slug)
            end
          end
        end
      end

      pages.each do |page|
        next unless directory_for_page?(directories[page.directory], page)

        directories[page.directory].entries << page
      end

      directories[''].entries
    end

    private

    def directory_for_page?(directory, page)
      directory.entries.none? do |item|
        item.is_a?(WikiDirectory) && item.slug.casecmp?(page.slug)
      end
    end
  end

  def initialize(slug, entries = [])
    @slug = slug
    @entries = entries
  end

  def title
    WikiPage.unhyphenize(File.basename(slug))
  end

  # Relative path to the partial to be used when rendering collections
  # of this object.
  def to_partial_path
    'shared/wikis/wiki_directory'
  end
end