feat: Category API to handle linked categories and parent-sub categories (#4879)

app/models/category.rb

@@ -2,28 +2,56 @@
 #
 # Table name: categories
 #
-#  id                        :bigint           not null, primary key
-#  description               :text
-#  locale                    :string           default("en")
-#  name                      :string
-#  position                  :integer
-#  slug                      :string           not null
-#  created_at                :datetime         not null
-#  updated_at                :datetime         not null
-#  account_id                :integer          not null
-#  portal_id                 :integer          not null
+#  id                 :bigint           not null, primary key
+#  description        :text
+#  locale             :string           default("en")
+#  name               :string
+#  position           :integer
+#  slug               :string           not null
+#  created_at         :datetime         not null
+#  updated_at         :datetime         not null
+#  account_id         :integer          not null
+#  linked_category_id :bigint
+#  parent_category_id :bigint
+#  portal_id          :integer          not null
 #
 # Indexes
 #
+#  index_categories_on_linked_category_id             (linked_category_id)
 #  index_categories_on_locale                         (locale)
 #  index_categories_on_locale_and_account_id          (locale,account_id)
+#  index_categories_on_parent_category_id             (parent_category_id)
 #  index_categories_on_slug_and_locale_and_portal_id  (slug,locale,portal_id) UNIQUE
 #
+# Foreign Keys
+#
+#  fk_rails_...  (linked_category_id => categories.id)
+#  fk_rails_...  (parent_category_id => categories.id)
+#
 class Category < ApplicationRecord
   belongs_to :account
   belongs_to :portal
   has_many :folders, dependent: :destroy_async
   has_many :articles, dependent: :nullify
+  has_many :category_related_categories,
+           class_name: :RelatedCategory,
+           dependent: :destroy_async
+  has_many :related_categories,
+           through: :category_related_categories,
+           class_name: :Category,
+           dependent: :nullify
+  has_many :sub_categories,
+           class_name: :Category,
+           foreign_key: :parent_category_id,
+           dependent: :nullify,
+           inverse_of: 'parent_category'
+  has_many :linked_categories,
+           class_name: :Category,
+           foreign_key: :linked_category_id,
+           dependent: :nullify,
+           inverse_of: 'linked_category'
+  belongs_to :parent_category, class_name: :Category, optional: true
+  belongs_to :linked_category, class_name: :Category, optional: true
 
   before_validation :ensure_account_id
   validates :account_id, presence: true
@@ -31,6 +59,7 @@ class Category < ApplicationRecord
   validates :name, presence: true
   validates :locale, uniqueness: { scope: %i[slug portal_id],
                                    message: 'should be unique in the category and portal' }
+  accepts_nested_attributes_for :related_categories
 
   scope :search_by_locale, ->(locale) { where(locale: locale) if locale.present? }
 

app/models/related_category.rb

@@ -0,0 +1,19 @@
+# == Schema Information
+#
+# Table name: related_categories
+#
+#  id                 :bigint           not null, primary key
+#  created_at         :datetime         not null
+#  updated_at         :datetime         not null
+#  category_id        :bigint
+#  related_category_id :bigint
+#
+# Indexes
+#
+#  index_related_categories_on_category_id_and_related_category_id  (category_id,related_category_id) UNIQUE
+#  index_related_categories_on_related_category_id_and_category_id  (related_category_id,category_id) UNIQUE
+#
+class RelatedCategory < ApplicationRecord
+  belongs_to :related_category, class_name: 'Category'
+  belongs_to :category, class_name: 'Category'
+end