// api_v1/scanner/scanActivitiesUser.js
const path = require('path');
const fsp = require('fs/promises');

const scanActivity = require('./scanActivity');
const { log } = require('./logger');
const { WEB_ROOT, SUPPORTED_ACTIVITY_EXTS } = require('../config');
const writeJsonAtomic = require('./writeJsonAtomic');

// ---------------------------------------------------------
// ETA CALCULATOR
// ---------------------------------------------------------
function computeETA(startTime, current, total) {
  if (current === 0) return 'calcolo...';

  const elapsed = (Date.now() - startTime) / 1000;
  const rate = current / elapsed;
  const remaining = (total - current) / rate;

  const m = Math.floor(remaining / 60);
  const s = Math.floor(remaining % 60);

  return `${m}m ${s}s`;
}

// ---------------------------------------------------------
// PRIMA PASSATA: conta TUTTI i file reali ricorsivamente
// ---------------------------------------------------------
async function countActivityFilesUser(rootDir) {
  let count = 0;

  async function walk(dir) {
    let entries = [];

    try {
      entries = await fsp.readdir(dir, { withFileTypes: true });
    } catch {
      return;
    }

    for (const e of entries) {
      const abs = path.join(dir, e.name);

      if (e.isDirectory()) {
        await walk(abs);
      } else {
        const ext = path.extname(e.name).toLowerCase();

        if (SUPPORTED_ACTIVITY_EXTS.has(ext)) {
          count++;
        }
      }
    }
  }

  await walk(rootDir);
  return count;
}

// ---------------------------------------------------------
// SECONDA PASSATA: scansiona SOLO le cartelle vere
// ---------------------------------------------------------
async function scanActivitiesUser(userName, db) {
  log(`🔵 Inizio scan ATTIVITÀ per user=${userName}`);

  const activitiesRoot = path.resolve(__dirname, '..', '..', WEB_ROOT, 'activities');
  const userDir = path.join(activitiesRoot, userName, 'original');
  const statusPath = path.join(activitiesRoot, 'scan_status.json');

  let entries = [];

  try {
    entries = await fsp.readdir(userDir, { withFileTypes: true });
  } catch {
    log(`❌ Nessuna directory attività per utente ${userName}`);
    return [];
  }

  // Filtra SOLO cartelle vere dentro "original"
  const folders = entries
    .filter(e => e.isDirectory())
    .map(e => e.name);

  // ---------------------------------------------------------
  // RIMOZIONE CARTELLE CANCELLATE DAL FILESYSTEM
  // ---------------------------------------------------------
  const createDeleteFolderFunctions = require('./deleteFolder');
  const { deleteFolderForUser } = createDeleteFolderFunctions(db);

  const dbFolders = await db('activities')
    .where({ user: userName })
    .distinct('cartella')
    .pluck('cartella');

  for (const dbFolder of dbFolders) {
    if (!folders.includes(dbFolder)) {
      log(`🗑️ Cartella attività rimossa dal filesystem: ${dbFolder}`);
      await deleteFolderForUser(userName, dbFolder);
    }
  }

  // PRIMA PASSATA: conta i file reali
  const TOTAL_FILES = await countActivityFilesUser(userDir);
  const CURRENT = { value: 0 };
  const start = Date.now();

  log(`📊 Attività totali da scansionare: ${TOTAL_FILES}`);

  // Stato iniziale
  await writeJsonAtomic(statusPath, {
    current: 0,
    total: TOTAL_FILES,
    percent: 0,
    eta: 'calcolo...'
  });

  const allNewActivities = [];

  // SECONDA PASSATA: UNA SOLA SCANSIONE PER CARTELLA
  for (const cartella of folders) {
    log(`📁 Scan cartella attività: ${cartella}`);

    const newActivities = await scanActivity(
      cartella,
      userName,
      db,
      CURRENT,
      TOTAL_FILES,
      start,
      async () => {
        await writeJsonAtomic(statusPath, {
          current: CURRENT.value,
          total: TOTAL_FILES,
          percent: TOTAL_FILES > 0
            ? Math.round((CURRENT.value / TOTAL_FILES) * 100)
            : 100,
          eta: computeETA(start, CURRENT.value, TOTAL_FILES)
        });
      }
    );

    if (newActivities?.length) {
      allNewActivities.push(...newActivities);
    }
  }

  // Stato finale
  await writeJsonAtomic(statusPath, {
    current: TOTAL_FILES,
    total: TOTAL_FILES,
    percent: 100,
    eta: '0m 0s'
  });

  log(`🟣 Scan ATTIVITÀ COMPLETATO per user=${userName}. Nuove attività: ${allNewActivities.length}`);

  return allNewActivities;
}

module.exports = scanActivitiesUser;