const TASK = {
  key: 'unused-upload-sweep',
  title: 'Unused upload sweep',
  category: 'cleanup',
  trigger: 'recurring scheduled task, daily',
  purpose: 'remove uploaded media files that are no longer referenced.',
  taskType: 'recurring-run',
  intervalMs: 24 * 60 * 60 * 1000
};

function registerUnusedUploadSweepTask(options) {
  const backgroundTaskQueue = options && options.backgroundTaskQueue;
  const uploadSyncService = options && options.uploadSyncService;
  const collectUploadPathsFromDirectory = uploadSyncService && uploadSyncService.collectUploadPathsFromDirectory;
  const removeUnusedUploadFiles = uploadSyncService && uploadSyncService.removeUnusedUploadFiles;
  const pool = options && options.pool;
  const mediaDir = String(options && options.mediaDir || '').trim();

  if (!backgroundTaskQueue || typeof collectUploadPathsFromDirectory !== 'function' || typeof removeUnusedUploadFiles !== 'function' || !pool || !mediaDir) {
    throw new Error('registerUnusedUploadSweepTask requires the unused upload sweep dependencies.');
  }

  backgroundTaskQueue.registerRecurringTask({
    key: TASK.key,
    title: TASK.title,
    category: TASK.category,
    intervalMs: TASK.intervalMs,
    metadata: {
      mediaDir: mediaDir
    },
    run: async function () {
      const uploadPaths = await collectUploadPathsFromDirectory(mediaDir);
      if (!uploadPaths.length) {
        return;
      }

      await removeUnusedUploadFiles(pool, mediaDir, uploadPaths);
    }
  });
}

module.exports = { registerUnusedUploadSweepTask };