// scanner/scanPhoto.js
const path = require('path');
const fsp = require('fs/promises');

const { loadPreviousIndex, saveIndex } = require('./indexStore');
const scanCartella = require('./scanCartella');
const postWithAuth = require('./postWithAuth');

const {
  WEB_ROOT,
  SEND_PHOTOS,
  BASE_URL,
  WRITE_INDEX
} = require('../config');

const createCleanupFunctions = require('./orphanCleanup');

async function scanPhoto(dir, userName, db) {
  const start = Date.now();
  console.log(`\n🔵 Inizio scan globale per user=${userName}`);

  const previousIndexTree = await loadPreviousIndex();
  const nextIndexTree = JSON.parse(JSON.stringify(previousIndexTree || {}));

  const {
    buildIdsListForFolder,
    removeIdFromList,
    deleteThumbsById,
    deleteFromDB
  } = createCleanupFunctions(db);

  const photosRoot = path.resolve(__dirname, '..', '..', WEB_ROOT, 'photos');
  const userDir = path.join(photosRoot, userName, 'original');

  let totalNew = 0;
  let totalDeleted = 0;
  let totalUnchanged = 0;

  // 🔥 Array dei file nuovi/modificati (per DB e server)
  let newFiles = [];

  // ---------------------------------------------------------
  // SCAN DI UNA SINGOLA CARTELLA
  // ---------------------------------------------------------
  async function scanSingleFolder(user, cartella, absCartella) {
    console.log(`\n📁 Inizio cartella: ${cartella}`);

    let idsIndex = await buildIdsListForFolder(user, cartella);

    let newCount = 0;
    let unchangedCount = 0;
    let deletedCount = 0;

    // STREAMING DEI FILE
    for await (const m of scanCartella(user, cartella, absCartella, previousIndexTree)) {
      const fileName = m.path.split('/').pop();

      // ⚪ FILE INVARIATO
      if (m.unchanged) {
        console.log(`   ⚪ Invariato: ${fileName}`);
        idsIndex = removeIdFromList(idsIndex, m.id);
        unchangedCount++;
        continue;
      }

      // 🟢 FILE NUOVO O MODIFICATO
      console.log(`   🟢 Nuovo/Modificato: ${fileName}`);

      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
      };

      idsIndex = removeIdFromList(idsIndex, m.id);
      newCount++;

      // Aggiungiamo alla lista dei file nuovi
      newFiles.push(m);
    }

    // 🔴 ORFANI (FILE CANCELLATI)
    for (const orphanId of idsIndex) {
      const old = previousIndexTree?.[user]?.[cartella]?.[orphanId];
      const fileName = old?.path?.split('/').pop() || orphanId;

      console.log(`   🔴 Eliminato: ${fileName}`);

      await deleteThumbsById(orphanId);
      deleteFromDB(orphanId);

      const userTree = nextIndexTree[user];
      if (userTree?.[cartella]?.[orphanId]) {
        delete userTree[cartella][orphanId];
      }

      deletedCount++;
    }

    console.log(
      `📊 Fine cartella ${cartella}: invariati=${unchangedCount}, nuovi=${newCount}, cancellati=${deletedCount}`
    );

    totalNew += newCount;
    totalDeleted += deletedCount;
    totalUnchanged += unchangedCount;
  }

  // ---------------------------------------------------------
  // SCAN SOTTOCARTELLE
  // ---------------------------------------------------------
  let entries = [];
  try {
    entries = await fsp.readdir(userDir, { withFileTypes: true });
  } catch {
    console.log(`Nessuna directory per utente ${userName}`);
    return [];
  }

  for (const e of entries) {
    if (!e.isDirectory()) continue;
    const cartella = e.name;
    const absCartella = path.join(userDir, cartella);
    await scanSingleFolder(userName, cartella, absCartella);
  }

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

  // ---------------------------------------------------------
  // INVIO AL SERVER / POPOLAZIONE DB
  // ---------------------------------------------------------
  if (SEND_PHOTOS && BASE_URL && newFiles.length > 0) {
    for (const p of newFiles) {
      const fileName = p.path.split('/').pop();

      try {
        await postWithAuth(`${BASE_URL}/photos`, p);
        console.log(`📤 Inviato al server: ${fileName}`);
      } catch (err) {
        console.error(`Errore invio ${fileName}:`, err.message);
      }
    }
  }

  // ---------------------------------------------------------
  // FINE SCAN
  // ---------------------------------------------------------
  const elapsed = ((Date.now() - start) / 1000).toFixed(2);

  console.log(`\n🟣 Scan COMPLETATO: nuovi=${totalNew}, cancellati=${totalDeleted}, invariati=${totalUnchanged}`);
  console.log(`⏱ Tempo totale: ${elapsed}s\n`);

  return newFiles;
}

module.exports = scanPhoto;