fairmondo/fairmondo

#   Copyright (c) 2012-2017, Fairmondo eG.  This file is
#   licensed under the GNU Affero General Public License version 3 or later.
#   See the COPYRIGHT file for details.

class Category < ApplicationRecord
  extend FriendlyId
  friendly_id :slug_candidates, use: [:slugged, :finders]

  acts_as_nested_set

  # Associations
  has_and_belongs_to_many :articles
  has_and_belongs_to_many :active_articles, class_name: 'Article',
                                            conditions: { state: 'active' }
  # There is no possible way to keep a counter cache here

  belongs_to :parent, class_name: 'Category', counter_cache: :children_count

  # Validations
  validates :name, presence: true

  # Scopes
  CATEGORY_NAV_THRESHOLD = 38

  scope :sorted, -> { order(:name) }
  scope :roots, -> { where(parent_id: nil) }
  scope :all_by_id, -> { order('id ASC') }
  scope :other_category_last, -> {
    order("CASE WHEN name = 'Weitere' THEN 1 ELSE 0 END")
  } # i18n!
  scope :weighted, -> {
    where('weight >= ?', CATEGORY_NAV_THRESHOLD)
      .order('weight IS NULL, weight desc')
  }
  scope :other_category, -> { where(parent_id: nil, name: 'Weitere') } # 18n!
  scope :other_categories, -> {
    where 'parent_id IS NULL AND weight < ? OR weight IS NULL',
          CATEGORY_NAV_THRESHOLD
  }

  # Callbacks

  # Categories get created from rails_admin, and it seems not to trigger slug
  # generation at all. This sets it so that slugs always get regenerated on save
  def should_generate_new_friendly_id?
    true
  end

  # Methods

  delegate :name, to: :parent, prefix: true

  def sorted_children
    self.children.except(:order).other_category_last.sorted.includes(:children)
  end

  def sorted_siblings
    self.siblings.except(:order).other_category_last.sorted.includes(:children)
  end

  def self_and_sorted_siblings
    [self] + sorted_siblings
  end

  def children_with_active_articles
    delete_if_no_active_articles sorted_children.to_a
  end

  def num_articles_with_quantity
    Article.units_placed_for_categories(self_and_descendants)
  end

  def num_sold_articles time_range
    Article.units_sold_for_categories(self_and_descendants, time_range)
  end

  private

  def slug_candidates
    [:name, [:name, :id]]
  end

  def delete_if_no_active_articles array
    array.delete_if do |node|
      node.children.empty? && node.active_articles.empty?
    end
  end
end