# frozen_string_literal: true

module Ibrain
  module Loaders
    class AssociationCountLoader < GraphQL::Batch::Loader
      def initialize(model, association_name)
        super()
        @model = model
        @association_name = association_name
      end

      def perform(records)
        reflection = @model.reflect_on_association(@association_name)
        reflection.check_preloadable!

        klass = reflection.klass
        field = reflection.join_primary_key
        counts = klass.unscoped.where(field => records).group(field).count

        records.each do |record|
          record_key = record[reflection.active_record_primary_key]
          fulfill(record, counts[record_key] || 0)
        end
      end
    end
  end
end