import cron from 'node-cron';
import type { FastifyInstance } from 'fastify';
import { TRASH_RETENTION_DAYS } from '@family-wishlist/shared';
import { deleteLocalImageIfAny } from '../modules/images/storage.service.js';

async function purge(app: FastifyInstance): Promise<number> {
  const cutoff = new Date(Date.now() - TRASH_RETENTION_DAYS * 24 * 60 * 60 * 1000);
  const victims = await app.prisma.wish.findMany({
    where: { status: 'DELETED', deletedAt: { lt: cutoff } },
    select: { id: true, imageUrl: true },
  });
  if (victims.length === 0) return 0;

  await Promise.all(victims.map((v) => deleteLocalImageIfAny(v.imageUrl)));
  const res = await app.prisma.wish.deleteMany({
    where: { id: { in: victims.map((v) => v.id) } },
  });
  return res.count;
}

export function registerPurgeTrashJob(app: FastifyInstance): void {
  // Run daily at 03:17 (chosen to avoid common cron rush).
  const task = cron.schedule(
    '17 3 * * *',
    async () => {
      try {
        const count = await purge(app);
        if (count > 0) app.log.info({ count }, 'trash: purged expired wishes');
      } catch (err) {
        app.log.error({ err }, 'trash: purge failed');
      }
    },
    { scheduled: true, timezone: 'UTC' },
  );

  app.addHook('onClose', async () => {
    task.stop();
  });

  // Also run once on startup to catch up if backend was offline for a while.
  setTimeout(() => {
    purge(app)
      .then((count) => {
        if (count > 0) app.log.info({ count }, 'trash: startup purge');
      })
      .catch((err) => app.log.error({ err }, 'trash: startup purge failed'));
  }, 5_000);
}