// scanner/scanPhoto.js
const path = require('path');
const fsp = require('fs/promises');
const { loadPreviousIndex, saveIndex } = require('./indexStore');
const scanUserRoot = require('./scanUser');
const postWithAuth = require('./postWithAuth');
const { WEB_ROOT, SEND_PHOTOS, BASE_URL, WRITE_INDEX } = require('../config');

const COMMON = 'Common';

async function scanPhoto(dir, userName) {
  console.log(`[SCAN] Avvio scanPhoto per user=${userName}`);

  const previousIndexTree = await loadPreviousIndex();
  console.log(`[SCAN] previousIndexTree keys:`, Object.keys(previousIndexTree));

  const nextIndexTree = JSON.parse(JSON.stringify(previousIndexTree || {}));
  const photosRoot = path.resolve(__dirname, '..', '..', WEB_ROOT, 'photos');

  console.log(`[SCAN] photosRoot = ${photosRoot}`);

  let changes = [];

  // ---------------------------------------------------------
  // 1) ADMIN → scansiona tutti gli utenti
  // ---------------------------------------------------------
  if (userName === 'Admin') {
    let entries = [];
    try {
      entries = await fsp.readdir(photosRoot, { withFileTypes: true });
    } catch {
      console.error(`[SCAN] photosRoot non accessibile`);
      return [];
    }

    console.log(`[SCAN] Trovati ${entries.length} utenti/cartelle`);

    for (const e of entries) {
      if (!e.isDirectory()) continue;

      const user = e.name;
      if (user.toLowerCase() === COMMON.toLowerCase()) continue;

      const userDir = path.join(photosRoot, user, 'original');

      try {
        const st = await fsp.stat(userDir);
        if (!st.isDirectory()) continue;
      } catch {
        continue;
      }

      console.log(`[SCAN] → Scansiono utente: ${user}`);

      const userChanges = await scanUserRoot(user, userDir, previousIndexTree);

      for (const m of userChanges) {
        nextIndexTree[m.user] ??= {};
        nextIndexTree[m.user][m.cartella] ??= {};
        nextIndexTree[m.user][m.cartella][m.id] = {
          id: m.id,
          user: m.user,
          cartella: m.cartella,
          path: m.path,
          hash: m._indexHash
        };
      }

      changes.push(...userChanges);
    }

    // Common
    const commonDir = path.join(photosRoot, COMMON, 'original');
    try {
      const st = await fsp.stat(commonDir);
      if (st.isDirectory()) {
        console.log(`[SCAN] → Scansiono Common`);
        const commonChanges = await scanUserRoot(COMMON, commonDir, previousIndexTree);

        for (const m of commonChanges) {
          nextIndexTree[COMMON] ??= {};
          nextIndexTree[COMMON][m.cartella] ??= {};
          nextIndexTree[COMMON][m.cartella][m.id] = {
            id: m.id,
            user: m.user,
            cartella: m.cartella,
            path: m.path,
            hash: m._indexHash
          };
        }

        changes.push(...commonChanges);
      }
    } catch {}
  }

  // ---------------------------------------------------------
  // 2) NON-ADMIN → scansiona SOLO l’utente richiesto
  // ---------------------------------------------------------
  else {
    const userDir = path.join(photosRoot, userName, 'original');

    try {
      const st = await fsp.stat(userDir);
      if (st.isDirectory()) {
        console.log(`[SCAN] → Scansiono utente singolo: ${userName}`);

        const userChanges = await scanUserRoot(userName, userDir, previousIndexTree);

        for (const m of userChanges) {
          nextIndexTree[m.user] ??= {};
          nextIndexTree[m.user][m.cartella] ??= {};
          nextIndexTree[m.user][m.cartella][m.id] = {
            id: m.id,
            user: m.user,
            cartella: m.cartella,
            path: m.path,
            hash: m._indexHash
          };
        }

        changes.push(...userChanges);
      }
    } catch {
      console.log(`[SCAN] Nessuna directory per utente ${userName}`);
    }
  }

  // ---------------------------------------------------------
  // SALVA INDEX
  // ---------------------------------------------------------
  if (WRITE_INDEX) {
    await saveIndex(nextIndexTree);
  }

  // ---------------------------------------------------------
  // INVIA AL SERVER
  // ---------------------------------------------------------
  if (SEND_PHOTOS && BASE_URL && changes.length) {
    for (const p of changes) {
      try {
        await postWithAuth(`${BASE_URL}/photos`, p);
      } catch (err) {
        console.error('Errore invio:', err.message);
      }
    }
  }

  console.log(`SCAN COMPLETATA: ${changes.length} file aggiornati`);
  return changes;
}

module.exports = scanPhoto;