const db = require('../db/knex');

function parseTarget(value) {
  if (value == null) {
    return null;
  }

  const target = Number(value);

  if (
    !Number.isInteger(target)
    || target <= 0
  ) {
    throw new Error(
      'Il limite deve essere un intero positivo',
    );
  }

  return target;
}

async function selectPhotosWithoutJob(limit) {
  let query = db('photos as p')
    .leftJoin(
      'face_scan_jobs as j',
      'j.photo_id',
      'p.id',
    )
    .select('p.id')
    .whereNull('p.deleted_at')
    .whereNotNull('p.path')
    .where('p.path', '!=', '')
    .whereNull('j.photo_id')
    .andWhere((builder) => {
      builder
        .whereNull('p.mime_type')
        .orWhere(
          'p.mime_type',
          'like',
          'image/%',
        );
    })
    .orderBy('p.created_at', 'asc')
    .orderBy('p.id', 'asc');

  if (limit !== null) {
    query = query.limit(limit);
  }

  return query;
}

async function main() {
  const target = parseTarget(process.argv[2]);

  const existingResult = await db('face_scan_jobs')
    .count({ count: '*' })
    .first();

  const existingJobs =
    Number(existingResult?.count || 0);

  let slots = null;

  if (target !== null) {
    slots = Math.max(
      0,
      target - existingJobs,
    );
  }

  if (slots === 0) {
    console.log({
      target_jobs: target,
      jobs_before: existingJobs,
      photos_selected: 0,
      jobs_inserted: 0,
      jobs_after: existingJobs,
    });

    return;
  }

  const photos = await selectPhotosWithoutJob(
    slots,
  );

  let inserted = 0;

  await db.transaction(async (trx) => {
    for (const photo of photos) {
      await trx('face_scan_jobs').insert({
        photo_id: photo.id,
        status: 'pending',
        attempts: 0,
        faces_detected: null,
        execution_ms: null,
        applied_rotation: null,
        last_error: null,
        started_at: null,
        completed_at: null,
        created_at: trx.fn.now(),
        updated_at: trx.fn.now(),
      });

      inserted += 1;
    }
  });

  const finalResult = await db('face_scan_jobs')
    .count({ count: '*' })
    .first();

  const finalJobs =
    Number(finalResult?.count || 0);

  console.log({
    target_jobs: target,
    jobs_before: existingJobs,
    photos_selected: photos.length,
    jobs_inserted: inserted,
    jobs_after: finalJobs,
  });
}

main()
  .catch((error) => {
    console.error(
      '[enqueueFaceScanJobs] errore:',
      error.stack
        || error.message
        || error,
    );

    process.exitCode = 1;
  })
  .finally(async () => {
    await db.destroy();
  });