feat: Dedup enhancements (streaming, retry, filename mode, scroll, auto-select)

Iterazioni sul feature Dedup (v1.10.0) da subito-post-scaffolding:
- compute_fingerprint espone il vero errore invece del generico None,
  worker propaga l'err_msg via progress_callback esteso
- Retry automatico: -length 30 su "invalid data / decoding frame",
  -length 60 + -algorithm 1 su "fingerprint vuoto"
- Nuovo metodo "filename" (Jaccard sui token nome file) con algoritmo
  incrementale O(N·K) — utile per file corrotti o per anteprima veloce
- Streaming groups: sia fingerprint che filename emettono `dedup:group`
  appena un gruppo raggiunge >=2 file; JS accumula in Map per update
  in-place. Progress bar avanza in tempo reale
- Fix shape bug che dava "NaN duplicati" nella summary line
- .dedup-groups-scroll: max-height 55vh + overflow-y auto per non
  perdere l'header/footer scrollando molti gruppi
- Bottone "Seleziona tutti i consigliati" nel footer: ripristina la
  selezione di default (tutti tranne il TIENI marcati per cancellazione)
- .gitignore: dedup_cache.db (SQLite locale per macchina utente)

.gitignore

@@ -49,3 +49,7 @@ server/node_modules/
 server/.wrangler/
 server/.dev.vars
 server/dist/
+
+# Dedup local cache (SQLite fingerprint cache, per macchina dell'utente)
+dedup_cache.db
+dedup_cache.db-journal

api/bridge.py

@@ -1841,24 +1841,28 @@ class Api:
 
         directory = (payload.get("directory") or "").strip()
         recursive = bool(payload.get("recursive", True))
+        method = (payload.get("method") or "fingerprint").strip()
+        if method not in ("fingerprint", "filename"):
+            method = "fingerprint"
 
         if not directory:
             return {"ok": False, "error": "Cartella non impostata"}
         if not os.path.isdir(directory):
             return {"ok": False, "error": "Cartella non trovata"}
 
-        # Persist last folder/recursive
+        # Persist last folder/recursive/method
         try:
             cfg = load_config()
             cfg["dedup_last_folder"] = directory
             cfg["dedup_recursive"] = recursive
+            cfg["dedup_method"] = method
             save_config(cfg)
         except Exception:
             pass
 
         self._dedup_thread = threading.Thread(
             target=self._dedup_worker,
-            args=(directory, recursive),
+            args=(directory, recursive, method),
             daemon=True,
         )
         self._dedup_thread.start()
@@ -1890,16 +1894,18 @@ class Api:
                 "failed": result.get("failed", []),
                 "moved_count": moved_n, "failed_count": failed_n}
 
-    def _dedup_worker(self, directory: str, recursive: bool) -> None:
+    def _dedup_worker(self, directory: str, recursive: bool,
+                       method: str = "fingerprint") -> None:
         """Esegue la scansione in background e emette progress/done."""
         view = "dedup"
         dedup.reset_stop()
-        self._log(view, f"[INFO] Scansione: {directory} (recursive={recursive})")
+        method_label = "audio fingerprint" if method == "fingerprint" else "nome file"
+        self._log(view, f"[INFO] Scansione: {directory} (metodo: {method_label}, recursive={recursive})")
 
         _last = [0.0]
         _THROTTLE = 0.05
 
-        def progress_cb(idx: int, total: int, filename: str, status: str) -> None:
+        def progress_cb(idx: int, total: int, filename: str, status: str, err_msg: str = "") -> None:
             # Throttle solo eventi 'computing'/'cached' (che possono essere migliaia)
             if status in ("computing", "cached"):
                 now = time.monotonic()
@@ -1910,6 +1916,8 @@ class Api:
                 "idx": idx, "total": total,
                 "filename": filename, "status": status,
             }
+            if err_msg:
+                payload_evt["error_msg"] = err_msg
             if total > 0:
                 payload_evt["overall"] = min(idx / total, 1.0)
             if status == "completed":
@@ -1918,12 +1926,22 @@ class Api:
             elif status == "stopped":
                 self._log(view, "[INFO] Scansione interrotta.")
             elif status == "error" and filename:
-                self._log(view, f"[ERRORE] {filename}: errore lettura")
+                detail = f": {err_msg}" if err_msg else ""
+                self._log(view, f"[ERRORE] {filename}{detail}")
             self._emit("dedup:progress", payload_evt)
 
+        def group_cb(group: dict) -> None:
+            """Emit streaming: appena un gruppo raggiunge/aggiorna >=2 file."""
+            try:
+                self._emit("dedup:group", group)
+            except Exception:
+                pass
+
         try:
             groups = dedup.scan_folder(directory, recursive=recursive,
-                                       progress_callback=progress_cb)
+                                       progress_callback=progress_cb,
+                                       method=method,
+                                       group_callback=group_cb)
         except Exception as e:
             self._log(view, f"[ERRORE] {e}")
             self._emit("dedup:done", {"ok": False, "error": str(e),

core/config.py

@@ -81,6 +81,7 @@ DEFAULTS = {
     # ---- Dedup (audio duplicati via Chromaprint) ----
     "dedup_last_folder": "",
     "dedup_recursive": True,
+    "dedup_method": "fingerprint",  # "fingerprint" | "filename"
     # ---- Licenza ----
     "license_key": "",          # chiave fornita all'utente via email
     "license_email": "",        # email associata all'acquisto

core/dedup.py

@@ -136,35 +136,36 @@ def _cache_put(conn: sqlite3.Connection, path: str, size: int, mtime: float,
 # ------------------------------------------------------------------
 # fpcalc
 # ------------------------------------------------------------------
-def compute_fingerprint(fpcalc: str, path: str) -> Optional[dict]:
-    """Chiama `fpcalc -json <file>` e ritorna {duration, fingerprint}.
-
-    Ritorna None su qualsiasi errore (fpcalc mancante, file corrotto,
-    timeout, JSON malformato).
-    """
-    if not fpcalc:
-        return None
+def _run_fpcalc(fpcalc: str, path: str, length: Optional[int] = None) -> dict:
+    """Esegue fpcalc una volta. Ritorna {duration, fingerprint} su successo
+    o {_error: str} su fallimento."""
+    cmd = [fpcalc, "-json"]
+    if length is not None:
+        cmd += ["-length", str(length)]
+    cmd.append(str(path))
     try:
         proc = subprocess.run(
-            [fpcalc, "-json", str(path)],
+            cmd,
             capture_output=True,
             text=True,
             timeout=_FPCALC_TIMEOUT_SEC,
             **subprocess_flags(),
         )
     except subprocess.TimeoutExpired:
-        return None
-    except (OSError, ValueError):
-        return None
+        return {"_error": f"timeout {_FPCALC_TIMEOUT_SEC}s"}
+    except (OSError, ValueError) as e:
+        return {"_error": f"subprocess: {e}"}
     if proc.returncode != 0:
-        return None
+        err = (proc.stderr or proc.stdout or "").strip().splitlines()
+        msg = err[-1] if err else f"exit {proc.returncode}"
+        return {"_error": msg[:200]}
     try:
         data = json.loads(proc.stdout or "{}")
-    except (json.JSONDecodeError, ValueError):
-        return None
+    except (json.JSONDecodeError, ValueError) as e:
+        return {"_error": f"JSON malformato: {e}"}
     fp = data.get("fingerprint")
     if not fp:
-        return None
+        return {"_error": "fingerprint vuoto (audio troppo corto?)"}
     try:
         dur = float(data.get("duration") or 0)
     except (TypeError, ValueError):
@@ -172,6 +173,64 @@ def compute_fingerprint(fpcalc: str, path: str) -> Optional[dict]:
     return {"duration": dur, "fingerprint": str(fp)}
 
 
+def compute_fingerprint(fpcalc: str, path: str) -> Optional[dict]:
+    """Chiama fpcalc e ritorna {duration, fingerprint} o {_error}.
+
+    Se il primo tentativo (full length) fallisce con "Invalid data" o simili
+    (frame audio corrotti che libav rifiuta), riprova con `-length 30`.
+    Molti file danneggiati hanno i frame corrotti nella parte finale e
+    limitando la scansione ai primi 30s si riesce a estrarre comunque
+    un fingerprint affidabile (30s bastano per l'unicità Chromaprint).
+    """
+    if not fpcalc:
+        return {"_error": "fpcalc non trovato nel bundle"}
+
+    res = _run_fpcalc(fpcalc, path)
+    if "fingerprint" in res:
+        return res
+
+    err_msg = res.get("_error", "").lower()
+
+    # Retry 1: frame audio corrotti → riduci finestra a 30s
+    corrupt_signals = ("invalid data", "decoding audio frame",
+                       "error while decoding", "invalid frame")
+    if any(sig in err_msg for sig in corrupt_signals):
+        res2 = _run_fpcalc(fpcalc, path, length=30)
+        if "fingerprint" in res2:
+            res2["_partial"] = True  # 30s soltanto
+            return res2
+
+    # Retry 2: fingerprint vuoto → prova con finestra piu' lunga (60s)
+    # nel caso l'intro sia silenzio/muto (chromaprint richiede audio "reale")
+    if "vuoto" in err_msg or "empty" in err_msg:
+        res2 = _run_fpcalc(fpcalc, path, length=60)
+        if "fingerprint" in res2:
+            res2["_partial"] = True
+            return res2
+        # Ancora vuoto → prova algoritmo differente (chromaprint algo 1)
+        # tramite subprocess diretto perche' _run_fpcalc non lo supporta
+        try:
+            proc = subprocess.run(
+                [fpcalc, "-json", "-length", "60", "-algorithm", "1", str(path)],
+                capture_output=True, text=True,
+                timeout=_FPCALC_TIMEOUT_SEC,
+                **subprocess_flags(),
+            )
+            if proc.returncode == 0:
+                data = json.loads(proc.stdout or "{}")
+                fp = data.get("fingerprint")
+                if fp:
+                    return {
+                        "duration": float(data.get("duration") or 0),
+                        "fingerprint": str(fp),
+                        "_partial": True,
+                    }
+        except Exception:
+            pass
+
+    return res
+
+
 # ------------------------------------------------------------------
 # Scan
 # ------------------------------------------------------------------
@@ -193,10 +252,97 @@ def _iter_audio_files(directory: str, recursive: bool) -> list[Path]:
     return files
 
 
+def _scan_by_filename(files: list, progress_callback: Optional[Callable],
+                       group_callback: Optional[Callable] = None,
+                       similarity_threshold: float = 0.8) -> list[list[dict]]:
+    """Raggruppa file per similarità nome (Jaccard sui token normalizzati),
+    algoritmo INCREMENTALE: per ogni nuovo file cerca match tra i gruppi già
+    formati (lookup O(K) dove K = numero gruppi). Emette streaming via
+    `group_callback` appena un gruppo raggiunge ≥ 2 file.
+    """
+    from core.upgrader import _normalize_stem  # riuso
+
+    def _pc(idx, total_n, name, status, err=""):
+        if not progress_callback:
+            return
+        try:
+            progress_callback(idx, total_n, name, status, err)
+        except TypeError:
+            progress_callback(idx, total_n, name, status)
+
+    def _gc(group_id: str, entries: list) -> None:
+        if group_callback:
+            try:
+                group_callback({"id": group_id, "entries": list(entries)})
+            except Exception:
+                pass
+
+    total = len(files)
+    # Ogni voce: {"id": str, "key_tokens": frozenset, "entries": [dict]}
+    groups: list = []
+
+    for i, fp_path in enumerate(files, start=1):
+        if is_stopped():
+            _pc(i - 1, total, "", "stopped")
+            break
+        try:
+            size = fp_path.stat().st_size
+        except OSError as e:
+            _pc(i, total, fp_path.name, "error", f"stat: {e}")
+            continue
+        tokens = frozenset(_normalize_stem(fp_path.stem))
+        if not tokens:
+            _pc(i, total, fp_path.name, "error", "nome senza token utili")
+            continue
+        try:
+            bitrate = get_bitrate(fp_path)
+        except Exception:
+            bitrate = 0
+        entry = {
+            "path": str(fp_path), "size": size, "bitrate": bitrate,
+            "duration": 0, "fingerprint": "",
+        }
+
+        # Cerca match nei gruppi già formati (lineare sui gruppi, non sui file)
+        matched = None
+        for g in groups:
+            common = len(tokens & g["key_tokens"])
+            if common == 0:
+                continue
+            union = len(tokens | g["key_tokens"])
+            if union > 0 and (common / union) >= similarity_threshold:
+                matched = g
+                break
+
+        if matched is not None:
+            was_solo = len(matched["entries"]) == 1
+            matched["entries"].append(entry)
+            matched["entries"].sort(key=lambda e: (-e["bitrate"], -e["size"]))
+            # Streaming: emit ogni volta che il gruppo diventa/rimane ≥ 2 file
+            _gc(matched["id"], matched["entries"])
+        else:
+            gid = f"fn_{len(groups)}_{fp_path.stem[:20]}"
+            groups.append({
+                "id": gid,
+                "key_tokens": set(tokens),
+                "entries": [entry],
+            })
+        _pc(i, total, fp_path.name, "cached")
+
+    # Ritorna solo i gruppi con >= 2 file
+    result = [sorted(g["entries"], key=lambda e: (-e["bitrate"], -e["size"]))
+              for g in groups if len(g["entries"]) >= 2]
+    result.sort(key=lambda g: -max(e["size"] for e in g))
+    _pc(total, total, "", "completed")
+    return result
+
+
 def scan_folder(
     directory: str,
     recursive: bool = True,
     progress_callback: Optional[Callable] = None,
+    method: str = "fingerprint",
+    group_callback: Optional[Callable] = None,
 ) -> list[list[dict]]:
     """Ritorna la lista di gruppi di file duplicati (>= 2 file).
 
@@ -207,8 +353,11 @@ def scan_folder(
     occupano piu' spazio vengono prima). All'interno di ogni gruppo:
     bitrate DESC, poi size DESC (il primo e' quello "da tenere").
 
-    Il fingerprint viene calcolato via `fpcalc -json` e messo in cache
-    SQLite. Al re-scan, se (size, mtime) invariati, non si rilancia fpcalc.
+    `method`:
+    - "fingerprint" (default): Chromaprint via fpcalc, preciso ma lento.
+      Cache SQLite persistente. Raggruppa per fingerprint identico.
+    - "filename": similarità Jaccard sui nomi file. Veloce ma euristico.
+      Non richiede fpcalc.
     """
     reset_stop()
     files = _iter_audio_files(directory, recursive)
@@ -218,6 +367,9 @@ def scan_folder(
             progress_callback(0, 0, "", "completed")
         return []
 
+    if method == "filename":
+        return _scan_by_filename(files, progress_callback, group_callback)
+
     fpcalc = find_fpcalc()
     if not fpcalc:
         # Senza fpcalc non possiamo fare nulla. Segnaliamo errore su ogni
@@ -231,18 +383,26 @@ def scan_folder(
         # {fingerprint: [entry, ...]}
         by_fp: dict[str, list[dict]] = {}
 
+        def _pc(idx, total_n, name, status, err=""):
+            """Chiama progress_callback in modo retrocompatibile: la firma
+            legacy è a 4 args, quella nuova a 5 con `error_msg` opzionale."""
+            if not progress_callback:
+                return
+            try:
+                progress_callback(idx, total_n, name, status, err)
+            except TypeError:
+                progress_callback(idx, total_n, name, status)
+
         for i, fp_path in enumerate(files, start=1):
             if is_stopped():
-                if progress_callback:
-                    progress_callback(i - 1, total, "", "stopped")
+                _pc(i - 1, total, "", "stopped")
                 return []
             try:
                 st = fp_path.stat()
                 size = st.st_size
                 mtime = st.st_mtime
-            except OSError:
-                if progress_callback:
-                    progress_callback(i, total, fp_path.name, "error")
+            except OSError as e:
+                _pc(i, total, fp_path.name, "error", f"stat: {e}")
                 continue
 
             path_str = str(fp_path)
@@ -251,15 +411,13 @@ def scan_folder(
                 fp_hash = cached["fingerprint"]
                 duration = cached["duration"]
                 bitrate = cached["bitrate"] or get_bitrate(fp_path)
-                if progress_callback:
-                    progress_callback(i, total, fp_path.name, "cached")
+                _pc(i, total, fp_path.name, "cached")
             else:
-                if progress_callback:
-                    progress_callback(i, total, fp_path.name, "computing")
+                _pc(i, total, fp_path.name, "computing")
                 res = compute_fingerprint(fpcalc, path_str)
-                if not res:
-                    if progress_callback:
-                        progress_callback(i, total, fp_path.name, "error")
+                if not res or not res.get("fingerprint"):
+                    err_msg = (res or {}).get("_error", "errore sconosciuto")
+                    _pc(i, total, fp_path.name, "error", err_msg)
                     continue
                 fp_hash = res["fingerprint"]
                 duration = res["duration"]
@@ -276,7 +434,21 @@ def scan_folder(
                 "duration": float(duration or 0),
                 "fingerprint": fp_hash,
             }
-            by_fp.setdefault(fp_hash, []).append(entry)
+            grp = by_fp.setdefault(fp_hash, [])
+            grp.append(entry)
+            # Streaming: appena il gruppo raggiunge (o supera) 2 elementi,
+            # emetti update (JS accumula/aggiorna in tempo reale)
+            if group_callback and len(grp) >= 2:
+                # Ordinamento intra-gruppo prima di emit (best-to-keep primo)
+                grp.sort(key=lambda e: (-int(e.get("bitrate") or 0),
+                                        -int(e.get("size") or 0)))
+                try:
+                    group_callback({
+                        "id": f"fp_{fp_hash[:24]}",
+                        "entries": list(grp),
+                    })
+                except Exception:
+                    pass
     finally:
         try:
             conn.close()

tests/test_dedup.py

@@ -160,12 +160,13 @@ class TestMoveToTrash:
 # compute_fingerprint
 # ------------------------------------------------------------------
 class TestComputeFingerprint:
-    def test_timeout_returns_none(self):
-        """Timeout di fpcalc -> None (non alza eccezione)."""
+    def test_timeout_returns_error(self):
+        """Timeout di fpcalc -> dict con _error, no fingerprint."""
         with mock.patch("core.dedup.subprocess.run",
                         side_effect=subprocess.TimeoutExpired(cmd="fpcalc", timeout=30)):
             result = dedup.compute_fingerprint("/fake/fpcalc", "/some/file.mp3")
-        assert result is None
+        assert result and "_error" in result and "timeout" in result["_error"]
+        assert "fingerprint" not in result
 
     def test_success_returns_dict(self):
         """Output JSON valido -> {duration, fingerprint}."""
@@ -176,15 +177,17 @@ class TestComputeFingerprint:
             result = dedup.compute_fingerprint("/fake/fpcalc", "/some/file.mp3")
         assert result == {"duration": 123.4, "fingerprint": "ABCDEF"}
 
-    def test_bad_json_returns_none(self):
+    def test_bad_json_returns_error(self):
         fake_proc = mock.Mock()
         fake_proc.returncode = 0
         fake_proc.stdout = "not json at all"
         with mock.patch("core.dedup.subprocess.run", return_value=fake_proc):
             result = dedup.compute_fingerprint("/fake/fpcalc", "/some/file.mp3")
-        assert result is None
+        assert result and "_error" in result and "JSON" in result["_error"]
+        assert "fingerprint" not in result
 
-    def test_missing_fpcalc_returns_none(self):
+    def test_missing_fpcalc_returns_error(self):
         # Nessuna chiamata subprocess se fpcalc e' vuoto
         result = dedup.compute_fingerprint("", "/some/file.mp3")
-        assert result is None
+        assert result and "_error" in result and "fpcalc" in result["_error"]
+        assert "fingerprint" not in result

webui/css/style.css

@@ -1962,3 +1962,11 @@ input[type="number"]::-webkit-inner-spin-button {
   border: 1px solid var(--border);
 }
 
+/* Lista risultati Dedup con scroll interno: l'header (hero sticky) e il
+   footer restano visibili anche se ci sono centinaia di gruppi. */
+.dedup-groups-scroll {
+  max-height: 55vh;
+  overflow-y: auto;
+  padding-right: 6px;  /* spazio per la scrollbar sul bordo */
+}
+

webui/index.html

@@ -1241,6 +1241,15 @@
               <span>Ricerca ricorsiva (include sottocartelle)</span>
             </label>
           </div>
+          <div class="beatport-header" style="margin-top:12px;gap:16px;">
+            <label style="display:flex;gap:8px;align-items:center;color:var(--text-2);font-size:13px;">
+              <span>Metodo:</span>
+              <select id="dedup-method" class="input" style="padding:4px 8px;font-size:13px;">
+                <option value="fingerprint">Audio fingerprint (preciso, lento)</option>
+                <option value="filename">Nome file (veloce, meno preciso)</option>
+              </select>
+            </label>
+          </div>
           <div id="dedup-status" class="beatport-status"></div>
         </div>
 
@@ -1259,10 +1268,13 @@
         <div class="card" id="dedup-summary-card" hidden>
           <div class="dedup-summary" id="dedup-summary-line"></div>
         </div>
-        <div id="dedup-groups-wrap"></div>
+        <div id="dedup-groups-wrap" class="dedup-groups-scroll"></div>
 
         <div class="dedup-footer-bar" id="dedup-footer-bar" hidden>
           <span class="counter" id="dedup-selected-count">0 file da cancellare</span>
+          <button id="dedup-select-suggested-btn" class="btn btn-ghost pill">
+            ✓ Seleziona tutti i consigliati
+          </button>
           <button id="dedup-trash-btn" class="btn btn-danger pill" disabled>
             <span class="ico">🗑</span> Sposta in cestino
           </button>

webui/js/app.js

@@ -3011,6 +3011,7 @@ const DedupUI = (() => {
     mstate.recursive = $("#dedup-recursive").checked;
     mstate.scanning = true;
     mstate.groups = [];
+    if (mstate._groupIndex) mstate._groupIndex.clear();
     mstate.toDelete.clear();
     renderGroups();
     $("#dedup-start-btn").disabled = true;
@@ -3022,11 +3023,13 @@ const DedupUI = (() => {
     $("#dedupCounter").textContent = "Scansione in corso…";
     setStatus("Scansione in corso...", "loading");
 
+    const method = $("#dedup-method")?.value || "fingerprint";
     let res;
     try {
       res = await window.pywebview.api.dedup_start_scan({
         directory: mstate.folder,
         recursive: mstate.recursive,
+        method,
       });
     } catch (e) {
       setStatus("Errore avvio: " + ((e && e.message) || e), "error");
@@ -3099,6 +3102,22 @@ const DedupUI = (() => {
     $("#dedup-start-btn").addEventListener("click", startScan);
     $("#dedup-stop-btn").addEventListener("click", stopScan);
     $("#dedup-trash-btn").addEventListener("click", moveSelectedToTrash);
+    $("#dedup-select-suggested-btn").addEventListener("click", () => {
+      // Reset selezione: per ogni gruppo, marca-per-cancellazione TUTTI
+      // tranne il primo (il "TIENI" consigliato). Non tocca i primi.
+      mstate.toDelete.clear();
+      mstate.groups.forEach((group) => {
+        for (let i = 1; i < group.length; i++) {
+          if (group[i] && group[i].path) mstate.toDelete.add(group[i].path);
+        }
+      });
+      // Sync checkbox nel DOM
+      $$("#dedup-groups-wrap .dedup-file-check").forEach((cb) => {
+        if (cb.disabled) return;  // skip il "TIENI"
+        cb.checked = true;
+      });
+      updateSelectedCount();
+    });
     $("#dedup-recursive").addEventListener("change", (e) => {
       mstate.recursive = e.target.checked;
     });
@@ -3114,6 +3133,9 @@ const DedupUI = (() => {
       $("#dedup-recursive").checked = cfg.dedup_recursive;
       mstate.recursive = cfg.dedup_recursive;
     }
+    if (cfg.dedup_method && $("#dedup-method")) {
+      $("#dedup-method").value = cfg.dedup_method;
+    }
 
     // Bridge handlers
     bridgeHandlers["dedup:progress"] = (p) => {
@@ -3136,8 +3158,36 @@ const DedupUI = (() => {
       }
     };
 
+    // Streaming: gruppi arrivano uno alla volta man mano che si formano.
+    // mstate.groups è una lista di ARRAY di entries (shape richiesta da
+    // renderGroups). Manteniamo un indice group_id → arrayRef per poter
+    // aggiornare in-place quando il gruppo cresce.
+    if (!mstate._groupIndex) mstate._groupIndex = new Map();
+    bridgeHandlers["dedup:group"] = (p) => {
+      if (!p || !p.id || !Array.isArray(p.entries)) return;
+      const idx = mstate._groupIndex;
+      const existing = idx.get(p.id);
+      if (existing) {
+        // Aggiorna elementi in-place (stesso riferimento array in mstate.groups)
+        existing.length = 0;
+        for (const e of p.entries) existing.push(e);
+      } else {
+        // Nuovo gruppo: array copia + tag `_id` non-enumerabile per il lookup
+        const arr = p.entries.slice();
+        Object.defineProperty(arr, "_id", { value: p.id, enumerable: false });
+        idx.set(p.id, arr);
+        mstate.groups.push(arr);
+      }
+      renderGroups();
+      setStatus(`Trovati ${mstate.groups.length} gruppi finora…`, "loading");
+    };
+
     bridgeHandlers["dedup:done"] = (p) => {
-      mstate.groups = (p && p.groups) || [];
+      // Se sono arrivati group via streaming, ignoriamo p.groups (già in mstate).
+      // Fallback: se lo streaming non ha popolato nulla, usiamo p.groups.
+      if (mstate.groups.length === 0 && p && Array.isArray(p.groups)) {
+        mstate.groups = p.groups;
+      }
       renderGroups();
       if (p && p.ok === false) {
         setStatus(p.error || "Errore scansione", "error");