# frozen_string_literal: true

# CleanupOldEventsJob - Removes events older than the configured retention period
#
# This job runs periodically (hourly) to clean up old events based on the
# event_retention_days setting. This helps keep the database size manageable
# and improves query performance.
#
# The retention period is configurable via the 'event_retention_days' setting
# (default: 90 days). This allows administrators to balance between historical
# data retention and database performance.
#
# Schedule: Every hour (configured in config/recurring.yml)
class CleanupOldEventsJob < ApplicationJob
  queue_as :background

  def perform
    retention_days = Setting.event_retention_days

    # Don't delete if retention is set to 0 or negative (disabled)
    if retention_days <= 0
      Rails.logger.info "CleanupOldEventsJob: Event retention disabled (retention_days: #{retention_days})"
      return 0
    end

    cutoff_date = retention_days.days.ago

    # Count events to be deleted
    old_events = Event.where('timestamp < ?', cutoff_date)
    count = old_events.count

    if count.zero?
      Rails.logger.info "CleanupOldEventsJob: No events older than #{retention_days} days found"
      return 0
    end

    Rails.logger.info "CleanupOldEventsJob: Deleting #{count} events older than #{retention_days} days (before #{cutoff_date})"

    # Delete in batches to avoid long-running transactions
    deleted_count = 0
    batch_size = 10_000

    old_events.in_batches(of: batch_size) do |batch|
      batch_count = batch.delete_all
      deleted_count += batch_count
      Rails.logger.info "CleanupOldEventsJob: Deleted batch of #{batch_count} events (total: #{deleted_count}/#{count})"
    end

    Rails.logger.info "CleanupOldEventsJob: Successfully deleted #{deleted_count} events"
    deleted_count
  end
end