// scanner/scanPhoto.js
const path = require('path');
const fs = require('fs');
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) {
  console.log(`[SCAN] Avvio scanPhoto 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 changes = [];

  // ---------------------------------------------------------
  // SCAN DI UNA SINGOLA CARTELLA
  // ---------------------------------------------------------
  async function scanSingleFolder(user, cartella, absCartella) {
    console.log(`\n==============================================`);
    console.log(`[SCAN] CARTELLA → ${user}/${cartella}`);
    console.log(`[DEBUG] SCANSIONE CARTELLA PATH: ${absCartella}`);
    console.log("==============================================");

    let idsIndex = await buildIdsListForFolder(user, cartella);

    const folderFiles = await scanCartella(
      user,
      cartella,
      absCartella,
      previousIndexTree
    );

    for (const m of folderFiles) {
      const prev = previousIndexTree?.[m.user]?.[m.cartella]?.[m.id];

      // 🔥 FILE INVARIATO
      if (prev && prev.hash === m._indexHash) {

        console.log("\n================ FILE INVARIATO ================");
        console.log("[FILE]:", m.path);

        console.log("[ID OGGI]:", JSON.stringify(m.id));
        console.log("[ID INDEX]:", JSON.stringify(prev.id));
        console.log("[UGUALI?]:", m.id === prev.id);

        console.log("[LEN OGGI]:", m.id.length);
        console.log("[LEN INDEX]:", prev.id.length);

        console.log("----- BYTE PER BYTE -----");
        const max = Math.min(m.id.length, prev.id.length, 64);
        for (let i = 0; i < max; i++) {
          const a = m.id[i];
          const b = prev.id[i];
          console.log(
            i.toString().padStart(2, "0"),
            a,
            b,
            a === b ? "==" : "!="
          );
        }

        console.log("----- idsIndex PRIMA -----");
        console.log(idsIndex.map(x => JSON.stringify(x)));

        const found = idsIndex.includes(m.id);
        console.log("[ID PRESENTE IN idsIndex?]:", found);

        const newList = idsIndex.filter(x => x !== m.id);

        console.log("----- idsIndex DOPO -----");
        console.log(newList.map(x => JSON.stringify(x)));

        idsIndex = newList;

        console.log("=================================================\n");
        continue;
      }

      // 🔥 FILE NUOVO O MODIFICATO
      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);
      changes.push(m);
    }

    // ---------------------------------------------------------
    // ORFANI
    // ---------------------------------------------------------
    if (idsIndex.length > 0) {
      console.log(`[ORPHAN] ID orfani trovati nella cartella ${cartella}:`);
      idsIndex.forEach(id => console.log(" -", id));
    } else {
      console.log(`[ORPHAN] Nessun ID orfano nella cartella ${cartella}`);
    }

    for (const orphanId of idsIndex) {
      console.log(`\n[ORPHAN] Eliminazione ID → ${orphanId}`);

      const thumbsDeleted = await deleteThumbsById(orphanId);
      console.log(`   → thumbsDeleted = ${thumbsDeleted}`);

      const dbDeleted = deleteFromDB(orphanId);
      console.log(`   → dbDeleted = ${dbDeleted}`);

      const userTree = nextIndexTree[user];
      if (userTree && userTree[cartella] && userTree[cartella][orphanId]) {
        delete userTree[cartella][orphanId];
        console.log(`   → nextIndexTree updated (removed ${orphanId})`);
      }

      console.log(`[ORPHAN] COMPLETATO → ${orphanId}`);
    }

    console.log(`==============================================\n`);
  }

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