feat: anomaly detection banner - notifica incongruenze inventario/transazioni

- New API endpoint 'inventory_anomalies': detects items where stored qty
  differs from tx history by >20% AND >50 units (phantom qty or missing qty)
- New API endpoint 'dismiss_anomaly': persists dismissal in anomaly_dismissed.json
- Banner system: new 'anomaly' type shown in dashboard alert banner
  with 'Correggi' (opens edit) and 'Ok, ignora' (dismisses) buttons
- CSS: banner-anomaly style (orange gradient)
- Fix: lo zucchero azzerato (175g fantasma rimossi), aggiunto a Bring!

api/index.php

@@ -202,6 +202,14 @@ try {
             getConsumptionPredictions($db);
             break;
 
+        case 'inventory_anomalies':
+            getInventoryAnomalies($db);
+            break;
+
+        case 'dismiss_anomaly':
+            dismissInventoryAnomaly();
+            break;
+
         case 'recent_popular_products':
             recentPopularProducts($db);
             break;
@@ -1261,6 +1269,100 @@ function undoTransaction(PDO $db): void {
 
 // ===== STATS =====
 
+/**
+ * Detect inventory items where the stored quantity is significantly inconsistent
+ * with the transaction history (sum of in - sum of out/waste).
+ *
+ * Two anomaly directions:
+ *  - PHANTOM (+diff): inventory > tx balance → quantity was manually inflated without an 'in' tx
+ *  - MISSING (-diff): inventory < tx balance → tx history says more should be here than stored
+ */
+function getInventoryAnomalies(PDO $db): void {
+    $rows = $db->query("
+        SELECT p.id AS product_id, p.name, p.brand, p.unit,
+               p.default_quantity, p.package_unit,
+               i.id AS inventory_id, i.quantity AS inv_qty, i.location,
+               COALESCE(tx_in.tot, 0)  AS total_in,
+               COALESCE(tx_out.tot, 0) AS total_out
+        FROM inventory i
+        JOIN products p ON p.id = i.product_id
+        LEFT JOIN (
+            SELECT product_id, SUM(quantity) AS tot
+            FROM transactions WHERE type = 'in' AND undone = 0 GROUP BY product_id
+        ) tx_in  ON tx_in.product_id  = p.id
+        LEFT JOIN (
+            SELECT product_id, SUM(quantity) AS tot
+            FROM transactions WHERE type IN ('out','waste') AND undone = 0 GROUP BY product_id
+        ) tx_out ON tx_out.product_id = p.id
+        WHERE i.quantity > 0
+    ")->fetchAll(PDO::FETCH_ASSOC);
+
+    // Anomaly dismissed keys stored in a simple JSON file
+    $dismissFile = __DIR__ . '/../data/anomaly_dismissed.json';
+    $dismissed   = [];
+    if (file_exists($dismissFile)) {
+        $dismissed = json_decode(file_get_contents($dismissFile), true) ?: [];
+    }
+
+    $anomalies = [];
+    foreach ($rows as $r) {
+        $invQty   = floatval($r['inv_qty']);
+        $expected = floatval($r['total_in']) - floatval($r['total_out']);
+        $diff     = $invQty - $expected;
+
+        // Threshold: difference must be >20% of inventory AND >50 units (avoid noise)
+        $threshold = max(1.0, $invQty * 0.20);
+        if (abs($diff) <= $threshold || abs($diff) <= 50) continue;
+
+        // Dismiss key: product_id + rounded expected (so re-adding stock resets the alert)
+        $key = 'a_' . $r['product_id'] . '_' . round($expected);
+        if (!empty($dismissed[$key])) continue;
+
+        $direction = $diff > 0 ? 'phantom' : 'missing';
+        $anomalies[] = [
+            'inventory_id' => (int)$r['inventory_id'],
+            'product_id'   => (int)$r['product_id'],
+            'name'         => $r['name'],
+            'brand'        => $r['brand'] ?: '',
+            'unit'         => $r['unit'],
+            'default_quantity' => $r['default_quantity'],
+            'package_unit' => $r['package_unit'],
+            'inv_qty'      => round($invQty, 2),
+            'expected_qty' => round($expected, 2),
+            'diff'         => round($diff, 2),
+            'direction'    => $direction,
+            'dismiss_key'  => $key,
+        ];
+    }
+
+    // Sort: largest absolute diff first
+    usort($anomalies, fn($a, $b) => abs($b['diff']) <=> abs($a['diff']));
+
+    echo json_encode(['success' => true, 'anomalies' => $anomalies], JSON_UNESCAPED_UNICODE);
+}
+
+/**
+ * Dismiss a specific anomaly so it no longer appears in the banner.
+ */
+function dismissInventoryAnomaly(): void {
+    $input = json_decode(file_get_contents('php://input'), true);
+    $key   = $input['dismiss_key'] ?? '';
+    if (empty($key) || !preg_match('/^a_\d+_-?\d+$/', $key)) {
+        echo json_encode(['success' => false, 'error' => 'Invalid key']);
+        return;
+    }
+    $dismissFile = __DIR__ . '/../data/anomaly_dismissed.json';
+    $dismissed   = [];
+    if (file_exists($dismissFile)) {
+        $dismissed = json_decode(file_get_contents($dismissFile), true) ?: [];
+    }
+    $dismissed[$key] = time();
+    // Clean up entries older than 90 days
+    $dismissed = array_filter($dismissed, fn($ts) => $ts > time() - 90 * 86400);
+    file_put_contents($dismissFile, json_encode($dismissed), LOCK_EX);
+    echo json_encode(['success' => true]);
+}
+
 function getStats(PDO $db): void {
     $totalProducts = $db->query("SELECT COUNT(*) FROM products")->fetchColumn();
     $totalItems = $db->query("SELECT COALESCE(SUM(quantity), 0) FROM inventory")->fetchColumn();

assets/css/style.css

@@ -4525,6 +4525,12 @@ body {
     background: linear-gradient(135deg, #ede9fe 0%, #ddd6fe 100%);
     border-color: #8b5cf6;
 }
+.alert-banner.banner-anomaly {
+    background: linear-gradient(135deg, #fff7ed 0%, #fed7aa 100%);
+    border-color: #ea580c;
+}
+.banner-anomaly .alert-banner-title { color: #9a3412; }
+.banner-anomaly .alert-banner-counter .banner-dot.active { background: #ea580c; }
 .alert-banner-inner {
     display: flex;
     align-items: flex-start;

assets/js/app.js

@@ -2354,9 +2354,10 @@ async function loadBannerAlerts() {
     if (!banner) { console.warn('[Banner] #alert-banner not found'); return; }
 
     try {
-        const [invData, predData] = await Promise.all([
+        const [invData, predData, anomalyData] = await Promise.all([
             api('inventory_list'),
             api('consumption_predictions').catch(err => { console.warn('[Banner] predictions fetch failed:', err); return { predictions: [] }; }),
+            api('inventory_anomalies').catch(err => { console.warn('[Banner] anomalies fetch failed:', err); return { anomalies: [] }; }),
         ]);
         const items = invData.inventory || [];
         const confirmed = getReviewConfirmed();
@@ -2401,6 +2402,13 @@ async function loadBannerAlerts() {
             _bannerQueue.push({ type: 'prediction', data: pred });
         });
 
+        // 5. Inventory anomalies (qty doesn't match transaction history)
+        const anomalies = anomalyData.anomalies || [];
+        anomalies.forEach(an => {
+            if (confirmed['an_' + an.dismiss_key]) return;
+            _bannerQueue.push({ type: 'anomaly', data: an });
+        });
+
         // Sort by priority (highest first)
         _bannerQueue.sort((a, b) => _bannerPriority(b) - _bannerPriority(a));
 
@@ -2453,6 +2461,10 @@ function _bannerPriority(entry) {
             // Higher deviation = more important, capped at 99
             return 100 + Math.min(dev, 99);
         }
+        case 'anomaly': {
+            // Phantom (inflated qty) = 250, Missing = 260 (slightly higher, means data is clearly wrong)
+            return entry.data.direction === 'missing' ? 260 : 250;
+        }
         default:
             return 0;
     }
@@ -2530,6 +2542,23 @@ function renderBannerItem() {
             btns += `<button class="btn-banner btn-banner-weigh" onclick="weighBannerItem()">⚖️ ${t('dashboard.banner_prediction_action_weigh')}</button>`;
         }
         actionsEl.innerHTML = btns;
+
+    } else if (entry.type === 'anomaly') {
+        const an = entry.data;
+        const diffAbs = Math.abs(an.diff);
+        const diffDisplay = `${diffAbs} ${an.unit}`;
+        const isPhantom = an.direction === 'phantom';
+        banner.className = 'alert-banner banner-anomaly';
+        iconEl.textContent = '🔍';
+        titleEl.textContent = `Anomalia inventario: ${an.name}${an.brand ? ' (' + an.brand + ')' : ''}`;
+        if (isPhantom) {
+            detailEl.innerHTML = `Inventario: <strong>${an.inv_qty}${an.unit}</strong> ma le transazioni ne giustificano solo <strong>${an.expected_qty}${an.unit}</strong> (+${diffDisplay} fantasma)`;
+        } else {
+            detailEl.innerHTML = `Le transazioni indicano <strong>${an.expected_qty}${an.unit}</strong> ma l'inventario ha solo <strong>${an.inv_qty}${an.unit}</strong> (mancano ${diffDisplay})`;
+        }
+        let btns = `<button class="btn-banner btn-banner-edit" onclick="editBannerAnomaly()">✏️ Correggi</button>`;
+        btns += `<button class="btn-banner btn-banner-ok" onclick="dismissBannerAnomaly()">✓ Ok, ignora</button>`;
+        actionsEl.innerHTML = btns;
     }
 
     if (_bannerQueue.length > 1) {
@@ -2585,6 +2614,23 @@ function editBannerPrediction() {
     editReviewItem(entry.data.inventory_id, entry.data.product_id);
 }
 
+function editBannerAnomaly() {
+    const entry = _bannerQueue[_bannerIndex];
+    if (!entry || entry.type !== 'anomaly') return;
+    _bannerEditPending = true;
+    editReviewItem(entry.data.inventory_id, entry.data.product_id);
+}
+
+function dismissBannerAnomaly() {
+    const entry = _bannerQueue[_bannerIndex];
+    if (!entry || entry.type !== 'anomaly') return;
+    const key = entry.data.dismiss_key;
+    setReviewConfirmed('an_' + key);
+    api('dismiss_anomaly', {}, 'POST', { dismiss_key: key }).catch(() => {});
+    showToast('Anomalia ignorata', 'info');
+    dismissBannerItem();
+}
+
 function weighBannerItem() {
     const entry = _bannerQueue[_bannerIndex];
     if (!entry) return;

index.html

@@ -11,7 +11,7 @@
     <title>EverShelf</title>
     <link rel="manifest" href="manifest.json">
     <link rel="icon" type="image/svg+xml" href="data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 100 100'><text y='.9em' font-size='90'>🏠</text></svg>">
-    <link rel="stylesheet" href="assets/css/style.css?v=20260420a">
+    <link rel="stylesheet" href="assets/css/style.css?v=20260421a">
     <!-- QuaggaJS for barcode scanning -->
     <script src="https://cdn.jsdelivr.net/npm/@ericblade/quagga2@1.8.4/dist/quagga.min.js"></script>
 </head>
@@ -1288,6 +1288,6 @@
     </div>
 </div>
 
-<script src="assets/js/app.js?v=20260420a"></script>
+<script src="assets/js/app.js?v=20260421a"></script>
 </body>
 </html>