code_example.rb

class Student < ApplicationRecord
    include LeadScoring::AttributeChangeListener
end

module LeadScoring
  module AttributeChangeListener
    extend ActiveSupport::Concern

    included do
      before_save :collect_changes_for_lead_scoring_notify
      after_create_commit -> { notify_attributes_changes_for_lead_scoring(event: 'create') }
      after_update_commit -> { notify_attributes_changes_for_lead_scoring(event: 'update') }
      after_destroy_commit -> { notify_attributes_changes_for_lead_scoring(event: 'destroy') }
    end

    def collect_changes_for_lead_scoring_notify
      @attributes_changes_for_lead_scoring ||= {}
      @attributes_changes_for_lead_scoring = @attributes_changes_for_lead_scoring.merge(changes)
    end

    def notify_attributes_changes_for_lead_scoring(event:)
      FactorCheckerMediator.new(
        self,
        changes: @attributes_changes_for_lead_scoring,
        event: event,
      ).notify

      @attributes_changes_for_lead_scoring = {}
    end
  end
end

module LeadScoring
  class FactorCheckerMediator
    ACTION_RECORD_CLASSES = [
      # ...
    ]

    SETTING_RECORD_CLASSES = [
      # ...
    ]

    MARK_RECORD_CLASSES = [
      # ...
    ]

    def initialize(record, changes:, event:)
      @record = record
      @changes = changes
      @event = event
    end

    def notify
      return if handler_klass.nil?

      handler = handler_klass.new(@record, changes: @changes, event: @event)
      handler.perform
    end

    private

    def handler_klass
      case @record
      when Student, Alumnus
        if @record.alumni?
          "LeadScoring::ActionRecordChangeHandler::Alumnus".constantize
        else
          "LeadScoring::ActionRecordChangeHandler::Student".constantize
        end
      when *ACTION_RECORD_CLASSES
        "LeadScoring::ActionRecordChangeHandler::#{@record.class.name}".constantize
      when *SETTING_RECORD_CLASSES
        "LeadScoring::SettingRecordChangeHandler::#{@record.class.name}".constantize
      when *MARK_RECORD_CLASSES
        "LeadScoring::MarkRecordChangeHandler::#{@record.class.name}".constantize
      end
    end
  end
end