module Evergreen
  class Page < ActiveRecord::Base
    extend FriendlyId
    self.table_name = "evergreen_pages"

    class << self
      def register_system_page(identifier, title)
        define_singleton_method("#{identifier}_page") { where(title: title).first_or_initialize }
      end

      def find_by_path(request_path)
        find_by! path: request_path
      end
    end

    scope :published, -> { where('drafted IS NULL or drafted = ?', false) }
    scope :drafted,   -> { where(drafted: true) }
    scope :hidden,    -> { where(hidden: true) }
    scope :visible,   -> { published.where('hidden IS NULL or hidden = ?', false) }

    acts_as_nested_set scope: 'type'
    friendly_id :navigation_label, use: :scoped, scope: :parent

    validates_uniqueness_of :path, if: :using_custom_path
    validates_presence_of :path, if: :using_custom_path

    after_save :update_path!, :update_descendants_path
    after_move :update_path!

    def navigation_label
      self[:navigation_label].present? ? self[:navigation_label] : title
    end

    def to_param
      path
    end

    def published?
      not drafted?
    end

    def state
      published? ? "published" : "drafted"
    end

    def update_path!
      return path if using_custom_path

      update_column :path, generate_path
      path
    end

    def inherited_attribute(*method_chain)
      value = method_chain.inject(self, :try)
      return value if value.present?
      upward_ancestors.detect { |ancestor| value = method_chain.inject(ancestor, :try) }
      value
    end

    def upward_ancestors
      ancestors.sort_by(&:level).reverse
    end

    def should_generate_new_friendly_id?
      title_changed? || navigation_label_changed?
    end

    private

    def generate_path
      slug_ancestry.join('/')
    end

    def slug_ancestry
      self_and_ancestors.map(&:slug).reject(&:blank?)
    end

    def update_descendants_path
      reload.descendants.each(&:update_path!)
    end
  end
end