// api_v1/scanner/scanCartella.js
const path = require('path');
const fsp = require('fs/promises');
const { sha256 } = require('./utils');
const { SUPPORTED_EXTS } = require('../config');

/**
 * scanCartella: genera informazioni sui file nella cartella
 * Non esegue processFile né scrive sul DB: lascia la logica di confronto a scanPhoto.
 *
 * Parametri:
 * - userName
 * - cartella
 * - absCartella
 * - db (opzionale, mantenuto per compatibilità)
 */
async function* scanCartella(userName, cartella, absCartella, db) {

  async function* walk(currentAbs, relPath = '') {
    let entries = [];
    try {
      entries = await fsp.readdir(currentAbs, { withFileTypes: true });
    } catch {
      return;
    }

    for (const e of entries) {
      const absPath = path.join(currentAbs, e.name);

      if (e.isDirectory()) {
        yield* walk(absPath, path.join(relPath, e.name));
        continue;
      }

      const ext = path.extname(e.name).toLowerCase();
      if (!SUPPORTED_EXTS.has(ext)) continue;

      const fileRelPath = relPath ? `${relPath}/${e.name}` : e.name;

      // ID deterministico (stesso criterio di prima)
      const id = sha256(`${userName}/${cartella}/${fileRelPath}`);

      // Stat veloce
      let st;
      try { st = await fsp.stat(absPath); } catch { continue; }

      yield {
        id,
        user: userName,
        cartella,
        name: e.name,
        relPath: fileRelPath,
        absPath,
        ext,
        stat: st,
        path: `/photos/${userName}/original/${cartella}/${fileRelPath}`
      };
    }
  }

  yield* walk(absCartella);
}

module.exports = scanCartella;