/**
 * Shared BullMQ → audit log glue.
 *
 * Each worker calls `attachWorkerAudit(worker, workerName)` after
 * defining itself. We listen on the worker's BullMQ events and emit:
 *
 *   - `job_failed` (severity error, source 'job') for every BullMQ
 *     `failed` event, regardless of attempt number. (Producers know if
 *     this was a final failure via the existing per-worker logic.)
 *   - `cron_run`   (severity info, source 'cron') for every successful
 *     completion of a job whose name matches a recurring scheduler
 *     entry — gives operators a heartbeat row per cron tick.
 *
 * Audit writes are fire-and-forget and never throw.
 */

import type { Job, Worker } from 'bullmq';

import { createAuditLog } from '@/lib/audit';
import { logger } from '@/lib/logger';

/**
 * Names that match recurring jobs registered in `scheduler.ts`.
 * Keep in sync — a typo here just means the cron-tick row gets logged
 * as a regular job instead of a cron run, no functional impact.
 */
const RECURRING_JOB_NAMES: ReadonlySet<string> = new Set([
  'signature-poll',
  'reminder-check',
  'reminder-overdue-check',
  'calendar-sync',
  'invoice-overdue-check',
  'tenure-expiry-check',
  'currency-refresh',
  'database-backup',
  'backup-cleanup',
  'session-cleanup',
  'report-scheduler',
  'notification-digest',
  'temp-file-cleanup',
  'form-expiry-check',
  'alerts-evaluate',
  'analytics-refresh',
  'gdpr-export-cleanup',
  'ai-usage-retention',
  'error-events-retention',
  'website-submissions-retention',
]);

export function attachWorkerAudit(worker: Worker, workerName: string): void {
  worker.on('failed', (job: Job | undefined, err: Error) => {
    void createAuditLog({
      userId: null,
      portId: null,
      action: 'job_failed',
      entityType: 'queue_job',
      entityId: job?.id ?? `${workerName}:unknown`,
      metadata: {
        worker: workerName,
        jobName: job?.name ?? 'unknown',
        attemptsMade: job?.attemptsMade ?? null,
        opts: job?.opts ? { attempts: job.opts.attempts } : null,
        error: err.message?.slice(0, 1024) ?? null,
      },
      severity: 'error',
      source: 'job',
    });
  });

  worker.on('completed', (job: Job) => {
    if (!RECURRING_JOB_NAMES.has(job.name)) return;
    void createAuditLog({
      userId: null,
      portId: null,
      action: 'cron_run',
      entityType: 'cron',
      entityId: job.name,
      metadata: {
        worker: workerName,
        jobId: job.id ?? null,
        durationMs: job.processedOn && job.finishedOn ? job.finishedOn - job.processedOn : null,
      },
      severity: 'info',
      source: 'cron',
    });
  });

  // Defensive logger — surface any audit-side failure to the worker log.
  worker.on('error', (err) => {
    logger.warn({ workerName, err }, 'BullMQ worker error');
  });
}