module OpenStax::Accounts
  class GroupNesting < ActiveRecord::Base

    delegate :requestor, :syncing, to: :container_group

    belongs_to :container_group, class_name: 'OpenStax::Accounts::Group',
               primary_key: :openstax_uid, inverse_of: :member_group_nestings
    belongs_to :member_group, class_name: 'OpenStax::Accounts::Group',
               primary_key: :openstax_uid, inverse_of: :container_group_nesting

    validates :container_group, presence: true
    validates :member_group, presence: true, uniqueness: true
    validates :requestor, presence: true, unless: :syncing_or_stubbing
    validate :no_loops, unless: :syncing_or_stubbing

    before_create :update_group_caches, unless: :syncing
    before_destroy :update_group_caches, unless: :syncing

    before_create :create_openstax_accounts_group_nesting, unless: :syncing_or_stubbing
    before_destroy :destroy_openstax_accounts_group_nesting, unless: :syncing_or_stubbing

    protected

    def syncing_or_stubbing
      syncing || OpenStax::Accounts.configuration.enable_stubbing?
    end

    def no_loops
      return if member_group.nil? ||\
                !member_group.subtree_group_ids.include?(container_group_id)
      errors.add(:base, 'would create a loop') if errors[:base].blank?
      false
    end

    def update_group_caches
      # Returns false if the update fails (aborting the save transaction)
      UpdateGroupCaches.call(self).errors.none?
    end

    def create_openstax_accounts_group_nesting
      return false if requestor.nil? || requestor.is_anonymous?

      OpenStax::Accounts::Api.create_group_nesting(requestor, self) if requestor.has_authenticated?
    end

    def destroy_openstax_accounts_group_nesting
      return false if requestor.nil? || requestor.is_anonymous?

      OpenStax::Accounts::Api.destroy_group_nesting(requestor, self) \
        if requestor.has_authenticated?
    end

  end
end