const TASK = {
  taskType: 'slide-thumbnail-refresh'
};

async function fetchPlayerInternalBaseUrl(pool) {
  const [rows] = await pool.query(
    `SELECT internal_base_url
     FROM d_players
     WHERE device_id = '1'
     LIMIT 1`
  );

  return String(rows && rows[0] && rows[0].internal_base_url || '').trim().replace(/\/$/, '') || null;
}

function registerSlideThumbnailRefreshTask(options) {
  const backgroundTaskQueue = options && options.backgroundTaskQueue;
  const captureSlideThumbnail = options && options.captureSlideThumbnail;
  const pool = options && options.pool;
  const common = options && options.common;
  const mediaDir = String(options && options.mediaDir || '').trim();

  if (!backgroundTaskQueue || typeof captureSlideThumbnail !== 'function' || !pool || !common || !mediaDir) {
    throw new Error('registerSlideThumbnailRefreshTask requires the slide thumbnail dependencies.');
  }

  // Refresh the slide thumbnail for one slide id.
  backgroundTaskQueue.setTaskHandler(TASK.taskType, async function (task) {
    const payload = task && task.payload ? task.payload : {};
    const slideId = Number(payload.slideId || 0);
    if (!Number.isFinite(slideId) || slideId <= 0) {
      throw new Error('Slide id is required.');
    }

    const playerInternalBaseUrl = await fetchPlayerInternalBaseUrl(pool);
    if (!playerInternalBaseUrl) {
      throw new Error('Player internal base URL is required.');
    }

    return captureSlideThumbnail({
      pool: pool,
      common: common,
      mediaDir: mediaDir,
      baseUrl: playerInternalBaseUrl,
      slideId: slideId,
      previousThumbnailPath: payload.previousThumbnailPath || null
    });
  });
}

module.exports = { registerSlideThumbnailRefreshTask };