feat: Gemini token usage counter (#82) + smarter qty suggestions 90-day EWMA (#70)

Backend (api/index.php): - callGemini() now extracts usageMetadata (tokens_in/tokens_out) from response - _recordAiUsage() persists monthly token data to data/ai_usage.json - callGeminiWithFallback() accepts $usageAction param; all 15 call sites labeled - gemini_usage endpoint: returns token stats, cost estimate, log info, DB size - smartShopping(): rolling 90-day EWMA (70% last-30d / 30% days-31-90) with fallback to all-time rate when <14 days of history Frontend (index.html + app.js): - New Info tab (ℹ️) in Settings with Gemini usage and System cards - _loadInfoTab() / _renderInfoTab(): loads on click, auto-refreshes every 30s - switchSettingsTab() stops auto-refresh when leaving Info tab Translations (it/en/de): settings.info.* keys
2026-05-18 06:23:42 +00:00
parent dc3cefefd0
commit 9f554c6e22
6 changed files with 339 additions and 35 deletions
@@ -18,6 +18,14 @@ define('_GH_TK_KEY', 'D1sp3ns4!Ev3r#26');
 define('GH_REPO',    'dadaloop82/EverShelf');
 define('PRICE_CACHE_PATH', __DIR__ . '/../data/shopping_price_cache.json');
 define('CATEGORY_CACHE_PATH', __DIR__ . '/../data/category_ai_cache.json');
+define('AI_USAGE_PATH', __DIR__ . '/../data/ai_usage.json');
+// Gemini pricing (USD per 1M tokens) — overridable via .env
+// gemini-2.5-flash: $0.15 input / $0.60 output
+// gemini-2.0-flash: $0.10 input / $0.40 output
+define('GEMINI_COST_25F_IN',  0.15);
+define('GEMINI_COST_25F_OUT', 0.60);
+define('GEMINI_COST_20F_IN',  0.10);
+define('GEMINI_COST_20F_OUT', 0.40);

 /** Decode the XOR-obfuscated GitHub token at runtime. */
 function _ghToken(): string {
@@ -135,6 +143,56 @@ if (($_GET['action'] ?? '') === 'get_logs') {
    exit;
 }

+// ── Gemini token usage + cost estimate ────────────────────────────────────────
+if (($_GET['action'] ?? '') === 'gemini_usage') {
+    header('Content-Type: application/json; charset=utf-8');
+    $data  = file_exists(AI_USAGE_PATH) ? (json_decode(file_get_contents(AI_USAGE_PATH), true) ?: []) : [];
+    $month = date('Y-m');
+    $cur   = $data[$month] ?? ['input_tokens' => 0, 'output_tokens' => 0, 'calls' => 0, 'by_action' => [], 'by_model' => []];
+
+    // Per-model cost calculation
+    $totalCost = 0.0;
+    foreach (($cur['by_model'] ?? []) as $mdl => $mu) {
+        $inRate  = str_contains($mdl, '2.5') ? (float)(env('GEMINI_COST_INPUT_PER_1M')  ?: GEMINI_COST_25F_IN)  : (float)(env('GEMINI_COST_INPUT_PER_1M')  ?: GEMINI_COST_20F_IN);
+        $outRate = str_contains($mdl, '2.5') ? (float)(env('GEMINI_COST_OUTPUT_PER_1M') ?: GEMINI_COST_25F_OUT) : (float)(env('GEMINI_COST_OUTPUT_PER_1M') ?: GEMINI_COST_20F_OUT);
+        $totalCost += ($mu['in'] / 1_000_000) * $inRate + ($mu['out'] / 1_000_000) * $outRate;
+    }
+    // Fallback if by_model not populated (old data)
+    if ($totalCost === 0.0 && ($cur['input_tokens'] > 0 || $cur['output_tokens'] > 0)) {
+        $inRate  = (float)(env('GEMINI_COST_INPUT_PER_1M')  ?: GEMINI_COST_25F_IN);
+        $outRate = (float)(env('GEMINI_COST_OUTPUT_PER_1M') ?: GEMINI_COST_25F_OUT);
+        $totalCost = ($cur['input_tokens'] / 1_000_000) * $inRate + ($cur['output_tokens'] / 1_000_000) * $outRate;
+    }
+
+    // Log sizes — EverLog::listFiles() returns [{file, size_kb, mtime}, ...]
+    $logFilesInfo = EverLog::listFiles();
+    $logBytes = 0;
+    foreach ($logFilesInfo as $lf) {
+        $logBytes += (int)(($lf['size_kb'] ?? 0) * 1024);
+    }
+
+    echo json_encode([
+        'month'         => $month,
+        'input_tokens'  => (int)$cur['input_tokens'],
+        'output_tokens' => (int)$cur['output_tokens'],
+        'calls'         => (int)$cur['calls'],
+        'by_action'     => $cur['by_action'] ?? [],
+        'by_model'      => $cur['by_model']  ?? [],
+        'cost_usd'      => round($totalCost, 6),
+        'log_bytes'     => $logBytes,
+        'log_level'     => EverLog::levelName(),
+        'log_files'     => count($logFilesInfo),
+        'db_bytes'      => file_exists(DB_PATH) ? filesize(DB_PATH) : 0,
+        'history'       => array_map(fn($k, $v) => [
+            'month'         => $k,
+            'input_tokens'  => (int)($v['input_tokens'] ?? 0),
+            'output_tokens' => (int)($v['output_tokens'] ?? 0),
+            'calls'         => (int)($v['calls'] ?? 0),
+        ], array_keys($data), array_values($data)),
+    ], JSON_UNESCAPED_UNICODE);
+    exit;
+}
+
 // ── Health check — startup diagnostic (no rate-limit, no auth required) ──────
 if (($_GET['action'] ?? '') === 'health_check') {
    $checks = [];
@@ -2904,27 +2962,72 @@ function callGemini(string $url, array $payload, int $timeout = 60): array {
        EverLog::aiResponse('gemini', strlen($lastBody), $elapsed, false, "HTTP {$lastCode}: " . substr($lastBody, 0, 300));
    }

+    $data = $lastBody ? json_decode($lastBody, true) : null;
+    // Extract token counts from Gemini usageMetadata
+    $usage = $data['usageMetadata'] ?? [];
+    $tokIn  = (int)($usage['promptTokenCount']     ?? 0);
+    $tokOut = (int)($usage['candidatesTokenCount'] ?? 0);
+
    return [
-        'http_code' => $lastCode,
-        'body'      => $lastBody,
-        'data'      => $lastBody ? json_decode($lastBody, true) : null,
+        'http_code'  => $lastCode,
+        'body'       => $lastBody,
+        'data'       => $data,
+        'tokens_in'  => $tokIn,
+        'tokens_out' => $tokOut,
    ];
 }

+/**
+ * Record Gemini token usage to the monthly ai_usage.json file.
+ * Called by callGeminiWithFallback after each successful call.
+ */
+function _recordAiUsage(string $model, int $tokIn, int $tokOut, string $action = ''): void {
+    if ($tokIn === 0 && $tokOut === 0) return;
+    $month = date('Y-m');
+    $data  = [];
+    if (file_exists(AI_USAGE_PATH)) {
+        $data = json_decode(file_get_contents(AI_USAGE_PATH), true) ?: [];
+    }
+    if (!isset($data[$month])) {
+        $data[$month] = ['input_tokens' => 0, 'output_tokens' => 0, 'calls' => 0, 'by_action' => [], 'by_model' => []];
+    }
+    $m = &$data[$month];
+    $m['input_tokens']  += $tokIn;
+    $m['output_tokens'] += $tokOut;
+    $m['calls']++;
+    if ($action) {
+        $m['by_action'][$action] = ($m['by_action'][$action] ?? 0) + 1;
+    }
+    if ($model) {
+        if (!isset($m['by_model'][$model])) $m['by_model'][$model] = ['in' => 0, 'out' => 0, 'calls' => 0];
+        $m['by_model'][$model]['in']    += $tokIn;
+        $m['by_model'][$model]['out']   += $tokOut;
+        $m['by_model'][$model]['calls'] += 1;
+    }
+    // Keep only last 13 months
+    krsort($data);
+    $data = array_slice($data, 0, 13, true);
+    @file_put_contents(AI_USAGE_PATH, json_encode($data, JSON_PRETTY_PRINT));
+    EverLog::debug('ai_usage recorded', ['model' => $model, 'in' => $tokIn, 'out' => $tokOut, 'action' => $action]);
+}
+
 /**
 * Like callGemini() but tries gemini-2.5-flash first, falls back to gemini-2.0-flash
 * on quota/rate-limit errors (429/503). Builds the URL from model name + API key.
 */
-function callGeminiWithFallback(string $apiKey, array $payload, int $timeout = 30): array {
+function callGeminiWithFallback(string $apiKey, array $payload, int $timeout = 30, string $usageAction = ''): array {
    $models   = ['gemini-2.5-flash', 'gemini-2.0-flash'];
-    $last     = ['http_code' => 0, 'body' => '', 'data' => null];
+    $last     = ['http_code' => 0, 'body' => '', 'data' => null, 'tokens_in' => 0, 'tokens_out' => 0];
    $promptLen = strlen(json_encode($payload));
    foreach ($models as $idx => $model) {
        $isFallback = $idx > 0;
        EverLog::aiCall($model, $promptLen, $isFallback);
        $url  = "https://generativelanguage.googleapis.com/v1beta/models/{$model}:generateContent?key={$apiKey}";
        $last = callGemini($url, $payload, $timeout);
-        if ($last['http_code'] === 200) return $last;
+        if ($last['http_code'] === 200) {
+            _recordAiUsage($model, $last['tokens_in'], $last['tokens_out'], $usageAction);
+            return $last;
+        }
        if ($last['http_code'] !== 429 && $last['http_code'] !== 503) return $last; // non-retryable
        EverLog::warn('AI model exhausted, trying fallback', ['model' => $model, 'code' => $last['http_code']]);
    }
@@ -3014,7 +3117,7 @@ function getOpenedShelfLifeDays(string $name, string $category, string $location
            'contents'         => [['parts' => [['text' => $prompt]]]],
            'generationConfig' => ['maxOutputTokens' => 8, 'temperature' => 0],
        ];
-        $result = callGeminiWithFallback($apiKey, $payload, 12);
+        $result = callGeminiWithFallback($apiKey, $payload, 12, 'shelf_life');
        if ($result['http_code'] === 200) {
            $text = trim($result['data']['candidates'][0]['content']['parts'][0]['text'] ?? '');
            $parsed = (int)preg_replace('/\D/', '', $text);
@@ -3280,7 +3383,7 @@ function geminiReadExpiry(): void {
        ]
    ];
    
-    $result   = callGeminiWithFallback($apiKey, $payload, 30);
+    $result   = callGeminiWithFallback($apiKey, $payload, 30, 'expiry_ocr');
    $httpCode = $result['http_code'];

    if ($httpCode !== 200) {
@@ -3434,7 +3537,7 @@ PROMPT;
        ]
    ];

-    $result   = callGeminiWithFallback($apiKey, $payload, 90);
+    $result   = callGeminiWithFallback($apiKey, $payload, 90, 'chat');
    $httpCode = $result['http_code'];

    if ($httpCode !== 200) {
@@ -3939,7 +4042,7 @@ PROMPT;
        ]
    ];

-    $result   = callGeminiWithFallback($apiKey, $payload, 60);
+    $result   = callGeminiWithFallback($apiKey, $payload, 60, 'recipe');
    $httpCode = $result['http_code'];

    if ($httpCode !== 200) {
@@ -4223,7 +4326,7 @@ PROMPT;
        'generationConfig' => ['temperature' => 0.1, 'maxOutputTokens' => 8192]
    ];

-    $result = callGeminiWithFallback($apiKey, $payload, 45);
+    $result = callGeminiWithFallback($apiKey, $payload, 45, 'chat_recipe');

    if ($result['http_code'] !== 200) {
        echo json_encode(['success' => false, 'error' => $result['data']['error']['message'] ?? 'gemini_error']);
@@ -4339,7 +4442,7 @@ PROMPT;
        'generationConfig' => ['temperature' => 0.7, 'maxOutputTokens' => 8192],
    ];

-    $result = callGeminiWithFallback($apiKey, $payload, 45);
+    $result = callGeminiWithFallback($apiKey, $payload, 45, 'recipe_ingredient');

    if ($result['http_code'] !== 200) {
        echo json_encode(['success' => false, 'error' => $result['data']['error']['message'] ?? 'gemini_error']);
@@ -5102,7 +5205,7 @@ PROMPT;
        ]
    ];

-    $result   = callGeminiWithFallback($apiKey, $payload, 30);
+    $result   = callGeminiWithFallback($apiKey, $payload, 30, 'identify_product');
    $httpCode = $result['http_code'];

    if ($httpCode !== 200) {
@@ -5515,7 +5618,7 @@ PROMPT;
        'generationConfig' => ['temperature' => 0.1, 'maxOutputTokens' => 16],
    ];

-    $result = callGeminiWithFallback($apiKey, $payload, 15);
+    $result = callGeminiWithFallback($apiKey, $payload, 15, 'classify_category');
    if ($result['http_code'] !== 200 || !isset($result['data']['candidates'][0])) return null;

    $text = trim($result['data']['candidates'][0]['content']['parts'][0]['text'] ?? '');
@@ -6495,6 +6598,7 @@ function smartShopping(PDO $db): void {
    }

    // 3. Get transaction stats per product (exclude undone=1 corrections)
+    // Also compute rolling 90-day consumption for smarter quantity suggestions (#70)
    $txStmt = $db->query("
        SELECT product_id,
               COUNT(CASE WHEN type IN ('out','waste') AND undone=0 THEN 1 END) as use_count,
@@ -6503,7 +6607,9 @@ function smartShopping(PDO $db): void {
               SUM(CASE WHEN type = 'in' AND undone=0 THEN quantity ELSE 0 END) as total_bought,
               MIN(CASE WHEN type = 'in' AND undone=0 THEN created_at END) as first_in,
               MAX(CASE WHEN type = 'in' AND undone=0 THEN created_at END) as last_in,
-               MAX(CASE WHEN type IN ('out','waste') AND undone=0 THEN created_at END) as last_out
+               MAX(CASE WHEN type IN ('out','waste') AND undone=0 THEN created_at END) as last_out,
+               SUM(CASE WHEN type IN ('out','waste') AND undone=0 AND created_at >= datetime('now','-90 days') THEN quantity ELSE 0 END) as used_90d,
+               SUM(CASE WHEN type IN ('out','waste') AND undone=0 AND created_at >= datetime('now','-30 days') THEN quantity ELSE 0 END) as used_30d
        FROM transactions
        GROUP BY product_id
    ");
@@ -6581,19 +6687,40 @@ function smartShopping(PDO $db): void {
        $lastOut = $tx && $tx['last_out'] ? strtotime($tx['last_out']) : null;
        $daysSinceFirst = $firstIn ? max(1, ($now - $firstIn) / 86400) : 999;

-        // Average daily consumption rate.
-        // Use the "effective tracking period" (first purchase → last activity) rather than
-        // first purchase → now, so idle periods after last use don't deflate the rate.
-        // Example: Aglio bought 60 days ago but last used 34 days ago → use 34-day window.
-        $lastActivity = max($lastIn ?? 0, $lastOut ?? 0);
-        $activitySpan = ($firstIn && $lastActivity > $firstIn) ? ($lastActivity - $firstIn) : 0;
-        // Guard: if all activity fits within 24h (e.g. bought & consumed same day / seconds apart),
-        // effectiveDays would collapse to 1 → wildly inflated daily rate (e.g. Pizza: in+out 9s apart).
-        // Fall back to daysSinceFirst (first purchase → now) for a conservative estimate.
-        $effectiveDays = ($activitySpan >= 86400)
-            ? max(1, $activitySpan / 86400)
-            : $daysSinceFirst;
-        $dailyRate = $effectiveDays < 999 && $totalUsed > 0 ? $totalUsed / $effectiveDays : 0;
+        // Average daily consumption rate — rolling 90-day window with EWMA weighting (#70).
+        // Priority: if we have ≥3 use events in last 90 days, use weighted blend
+        //   70% weight on last 30 days, 30% on days 31-90 → reacts to habit changes.
+        // Fallback: all-time effective-period rate (original logic).
+        $used90d = (float)($tx['used_90d'] ?? 0);
+        $used30d = (float)($tx['used_30d'] ?? 0);
+        $used60_90d = max(0, $used90d - $used30d); // consumption in days 31-90
+
+        $dailyRate30 = $used30d > 0 ? $used30d / 30.0 : 0;
+        $dailyRate60 = $used60_90d > 0 ? $used60_90d / 60.0 : 0;
+
+        // Use EWMA only when we have enough recent data
+        $useEwma = ($used90d > 0 && $daysSinceFirst >= 14);
+        if ($useEwma) {
+            if ($dailyRate30 > 0 && $dailyRate60 > 0) {
+                // Both windows have data → blend 70/30
+                $dailyRate = 0.70 * $dailyRate30 + 0.30 * $dailyRate60;
+            } elseif ($dailyRate30 > 0) {
+                $dailyRate = $dailyRate30; // only recent data
+            } else {
+                $dailyRate = $dailyRate60; // only older data
+            }
+        } else {
+            // Fallback: all-time effective-period rate (original logic)
+            $lastActivity = max($lastIn ?? 0, $lastOut ?? 0);
+            $activitySpan = ($firstIn && $lastActivity > $firstIn) ? ($lastActivity - $firstIn) : 0;
+            // Guard: if all activity fits within 24h (e.g. bought & consumed same day / seconds apart),
+            // effectiveDays would collapse to 1 → wildly inflated daily rate (e.g. Pizza: in+out 9s apart).
+            // Fall back to daysSinceFirst (first purchase → now) for a conservative estimate.
+            $effectiveDays = ($activitySpan >= 86400)
+                ? max(1, $activitySpan / 86400)
+                : $daysSinceFirst;
+            $dailyRate = $effectiveDays < 999 && $totalUsed > 0 ? $totalUsed / $effectiveDays : 0;
+        }

        // Days of stock remaining
        $daysLeft = ($dailyRate > 0 && $qty > 0) ? $qty / $dailyRate : ($qty > 0 ? 999 : 0);
@@ -7151,7 +7278,7 @@ function bringSuggestItems(PDO $db): void {
                . "Name and reason must be in Italian. Reason max 8 words.";

            $payload   = ['contents' => [['parts' => [['text' => $prompt]]]]];
-            $gemResult = callGeminiWithFallback($apiKey, $payload, 20);
+            $gemResult = callGeminiWithFallback($apiKey, $payload, 20, 'bring_suggest');

            $aiResult = null;
            if ($gemResult['http_code'] === 200) {
@@ -7822,7 +7949,7 @@ function geminiProductHint(): void {
        . "Output ONLY the JSON, no markdown, no extra text.";

    $payload = ['contents' => [['parts' => [['text' => $prompt]]]]];
-    $result  = callGeminiWithFallback($apiKey, $payload, 15);
+    $result  = callGeminiWithFallback($apiKey, $payload, 15, 'product_hint');

    if ($result['http_code'] !== 200) {
        echo json_encode(['success' => false, 'error' => 'gemini_error', 'http_code' => $result['http_code']]);
@@ -7919,7 +8046,7 @@ function geminiShoppingEnrich(PDO $db): void {
        . "Keep the same order and count as the input. Output ONLY the JSON array, no markdown.";

    $payload = ['contents' => [['parts' => [['text' => $prompt]]]]];
-    $result  = callGeminiWithFallback($apiKey, $payload, 20);
+    $result  = callGeminiWithFallback($apiKey, $payload, 20, 'shopping_enrich');

    if ($result['http_code'] !== 200) {
        echo json_encode(['success' => false, 'error' => 'gemini_error']);
@@ -7983,7 +8110,7 @@ function geminiNumberOCR(): void {
        'generationConfig' => ['temperature' => 0, 'maxOutputTokens' => 20, 'thinkingConfig' => ['thinkingBudget' => 0]]
    ];

-    $result = callGeminiWithFallback($apiKey, $payload, 10);
+    $result = callGeminiWithFallback($apiKey, $payload, 10, 'number_ocr');
    $text   = trim($result['text'] ?? '');
    $digits = preg_replace('/\D/', '', $text);

@@ -8045,7 +8172,7 @@ function geminiAnomalyExplain(): void {
        . "Be conversational and practical.";

    $payload = ['contents' => [['parts' => [['text' => $prompt]]]]];
-    $result  = callGeminiWithFallback($apiKey, $payload, 15);
+    $result  = callGeminiWithFallback($apiKey, $payload, 15, 'anomaly_explain');

    if ($result['http_code'] !== 200) {
        echo json_encode(['success' => false, 'error' => 'gemini_error']);
@@ -8131,7 +8258,7 @@ PROMPT;

    $payload = ['contents' => [['parts' => [['text' => $prompt]]]]];
    // 55s timeout — generous for large batches (set_time_limit(120) in getAllShoppingPrices)
-    $result  = callGeminiWithFallback($apiKey, $payload, 55);
+    $result  = callGeminiWithFallback($apiKey, $payload, 55, 'price_batch');

    if ($result['http_code'] !== 200) return [];

@@ -8189,7 +8316,7 @@ function guessCategoryFromAI(): void {
        ],
    ];

-    $result = callGeminiWithFallback($apiKey, $payload, 10);
+    $result = callGeminiWithFallback($apiKey, $payload, 10, 'guess_category');
    $raw    = strtolower(trim($result['data']['candidates'][0]['content']['parts'][0]['text'] ?? ''));
    $raw    = preg_replace('/[^a-z_ ]/', '', $raw);
    $raw    = trim($raw);
@@ -2203,6 +2203,104 @@ function _applySyncedSettings(serverSettings) {
    }
 }

+let _infoTabTimer = null;
+
+/**
+ * Load the Info tab: Gemini token usage + cost, log size, DB size, log level.
+ * Called on tab click; auto-refreshes every 30s while the tab is open.
+ */
+async function _loadInfoTab() {
+    // Cancel any previous auto-refresh
+    if (_infoTabTimer) { clearInterval(_infoTabTimer); _infoTabTimer = null; }
+    await _renderInfoTab();
+    // Auto-refresh every 30s while Info tab is visible
+    _infoTabTimer = setInterval(_renderInfoTab, 30_000);
+}
+
+async function _renderInfoTab() {
+    const aiEl  = document.getElementById('info-ai-content');
+    const sysEl = document.getElementById('info-system-content');
+    if (!aiEl && !sysEl) return;
+
+    try {
+        const d = await api('gemini_usage');
+        const s = getSettings();
+        const sym = s.price_currency === 'USD' ? '$' : (s.price_currency === 'GBP' ? '£' : '€');
+
+        // ── AI Usage card ────────────────────────────────────────────────────
+        if (aiEl) {
+            const totalTok  = (d.input_tokens || 0) + (d.output_tokens || 0);
+            const costUsd   = d.cost_usd || 0;
+
+            // Convert cost to display currency (rough fixed rates)
+            let costDisplay = '$' + costUsd.toFixed(4);
+            if (s.price_currency === 'EUR') costDisplay = '€' + (costUsd * 0.92).toFixed(4);
+            if (s.price_currency === 'GBP') costDisplay = '£' + (costUsd * 0.79).toFixed(4);
+
+            // By-action breakdown
+            const actions = d.by_action || {};
+            const actionRows = Object.entries(actions)
+                .sort((a, b) => b[1] - a[1])
+                .map(([k, v]) => `<tr><td style="padding:2px 8px 2px 0;color:var(--text-secondary);font-size:0.82rem">${k}</td><td style="font-variant-numeric:tabular-nums;font-size:0.82rem">${v} calls</td></tr>`)
+                .join('');
+
+            // By-model breakdown
+            const models = d.by_model || {};
+            const modelRows = Object.entries(models)
+                .map(([m, mv]) => `<tr><td style="padding:2px 8px 2px 0;color:var(--text-secondary);font-size:0.82rem">${m}</td><td style="font-variant-numeric:tabular-nums;font-size:0.82rem">${((mv.in||0)+(mv.out||0)).toLocaleString()} tok</td></tr>`)
+                .join('');
+
+            aiEl.innerHTML = `
+                <div style="display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-bottom:12px">
+                    <div style="background:var(--bg-secondary);border-radius:10px;padding:12px;text-align:center">
+                        <div style="font-size:1.4rem;font-weight:700;color:var(--accent)">${totalTok.toLocaleString()}</div>
+                        <div style="font-size:0.75rem;color:var(--text-secondary);margin-top:2px">${t('settings.info.total_tokens')}</div>
+                    </div>
+                    <div style="background:var(--bg-secondary);border-radius:10px;padding:12px;text-align:center">
+                        <div style="font-size:1.4rem;font-weight:700;color:#15803d">${costDisplay}</div>
+                        <div style="font-size:0.75rem;color:var(--text-secondary);margin-top:2px">${t('settings.info.est_cost')} (${d.month})</div>
+                    </div>
+                </div>
+                <div style="display:grid;grid-template-columns:1fr 1fr;gap:6px;margin-bottom:10px;font-size:0.82rem;color:var(--text-secondary)">
+                    <span>↑ ${t('settings.info.input_tok')}: <strong>${(d.input_tokens||0).toLocaleString()}</strong></span>
+                    <span>↓ ${t('settings.info.output_tok')}: <strong>${(d.output_tokens||0).toLocaleString()}</strong></span>
+                    <span>${t('settings.info.ai_calls')}: <strong>${d.calls||0}</strong></span>
+                </div>
+                ${actionRows ? `<details style="margin-top:6px"><summary style="font-size:0.82rem;cursor:pointer;color:var(--text-secondary)">${t('settings.info.by_action')}</summary><table style="margin-top:6px;border-collapse:collapse">${actionRows}</table></details>` : ''}
+                ${modelRows  ? `<details style="margin-top:4px"><summary style="font-size:0.82rem;cursor:pointer;color:var(--text-secondary)">${t('settings.info.by_model')}</summary><table style="margin-top:6px;border-collapse:collapse">${modelRows}</table></details>` : ''}
+                <p class="settings-hint" style="margin-top:8px">${t('settings.info.pricing_note')}</p>
+            `;
+        }
+
+        // ── System card ──────────────────────────────────────────────────────
+        if (sysEl) {
+            const logMb  = ((d.log_bytes || 0) / 1048576).toFixed(2);
+            const dbMb   = ((d.db_bytes  || 0) / 1048576).toFixed(2);
+            sysEl.innerHTML = `
+                <table style="border-collapse:collapse;width:100%;font-size:0.88rem">
+                    <tr style="border-bottom:1px solid var(--border)">
+                        <td style="padding:7px 0;color:var(--text-secondary)">${t('settings.info.db_size')}</td>
+                        <td style="padding:7px 0;font-weight:600;text-align:right">${dbMb} MB</td>
+                    </tr>
+                    <tr style="border-bottom:1px solid var(--border)">
+                        <td style="padding:7px 0;color:var(--text-secondary)">${t('settings.info.log_size')}</td>
+                        <td style="padding:7px 0;font-weight:600;text-align:right">${logMb} MB (${d.log_files||0} files)</td>
+                    </tr>
+                    <tr>
+                        <td style="padding:7px 0;color:var(--text-secondary)">${t('settings.info.log_level')}</td>
+                        <td style="padding:7px 0;font-weight:600;text-align:right">
+                            <span style="background:${d.log_level==='DEBUG'?'#dbeafe':d.log_level==='INFO'?'#dcfce7':d.log_level==='WARN'?'#fef9c3':'#fee2e2'};color:${d.log_level==='DEBUG'?'#1e40af':d.log_level==='INFO'?'#15803d':d.log_level==='WARN'?'#854d0e':'#991b1b'};padding:2px 8px;border-radius:6px;font-size:0.8rem">${d.log_level||'INFO'}</span>
+                        </td>
+                    </tr>
+                </table>
+            `;
+        }
+    } catch(e) {
+        if (aiEl)  aiEl.innerHTML  = `<p class="settings-hint">${t('error.generic')}</p>`;
+        if (sysEl) sysEl.innerHTML = `<p class="settings-hint">${t('error.generic')}</p>`;
+    }
+}
+
 /**
 * Populate the About section with the current app version from the server.
 */
@@ -3002,6 +3100,11 @@ async function saveSettings() {
 }

 function switchSettingsTab(btn, tabId) {
+    // Stop info-tab auto-refresh when leaving that tab
+    if (tabId !== 'tab-info' && _infoTabTimer) {
+        clearInterval(_infoTabTimer);
+        _infoTabTimer = null;
+    }
    document.querySelectorAll('.settings-tab').forEach(t => t.classList.remove('active'));
    document.querySelectorAll('.settings-panel').forEach(p => p.classList.remove('active'));
    btn.classList.add('active');
@@ -841,6 +841,7 @@
            <button class="settings-tab" onclick="switchSettingsTab(this, 'tab-tts')" data-tab="tab-tts" title="Voce (TTS)" data-i18n-title="settings.tab_tts">🔊</button>
            <button class="settings-tab" onclick="switchSettingsTab(this, 'tab-language')" data-tab="tab-language" title="Lingua" data-i18n-title="settings.tab_language">🌐</button>
            <button class="settings-tab" onclick="switchSettingsTab(this, 'tab-scale')" data-tab="tab-scale" title="Bilancia Smart" data-i18n-title="settings.scale.tab">⚖️</button>
+            <button class="settings-tab" onclick="switchSettingsTab(this, 'tab-info'); _loadInfoTab();" data-tab="tab-info" data-i18n-title="settings.info.tab" title="Info">ℹ️</button>
        </div>
        <div class="settings-panels">
            <!-- API Keys Tab -->
@@ -1335,6 +1336,25 @@
                    </div>
                </div>
            </div>
+
+            <!-- Info Tab -->
+            <div class="settings-panel" id="tab-info">
+                <!-- Gemini AI Usage card -->
+                <div class="settings-card">
+                    <h4 data-i18n="settings.info.ai_title">Gemini AI — Token Usage</h4>
+                    <p class="settings-hint" data-i18n="settings.info.ai_hint">Monthly consumption and estimated cost for the current API key.</p>
+                    <div id="info-ai-content" style="margin-top:10px">
+                        <p class="settings-hint" data-i18n="settings.info.loading">Loading…</p>
+                    </div>
+                </div>
+                <!-- System Info card -->
+                <div class="settings-card">
+                    <h4 data-i18n="settings.info.system_title">System</h4>
+                    <div id="info-system-content" style="margin-top:10px">
+                        <p class="settings-hint" data-i18n="settings.info.loading">Loading…</p>
+                    </div>
+                </div>
+            </div>
        </div>

        <!-- Kiosk app download banner (hidden inside kiosk WebView) -->
@@ -761,6 +761,24 @@
      "card_title": "♻️ Zero-Waste-Tipps",
      "card_hint": "Zeige während des Kochens Tipps zur Wiederverwendung von Abfällen (Schalen, Kochwasser usw.). Standardmäßig deaktiviert.",
      "label": "Tipps beim Kochen anzeigen"
+    },
+    "info": {
+      "tab": "Info",
+      "ai_title": "Gemini AI — Token-Nutzung",
+      "ai_hint": "Monatlicher Verbrauch und geschätzte Kosten für den aktuellen API-Schlüssel.",
+      "loading": "Laden…",
+      "total_tokens": "Token gesamt",
+      "est_cost": "Gesch. Kosten",
+      "input_tok": "Eingabe-Token",
+      "output_tok": "Ausgabe-Token",
+      "ai_calls": "KI-Aufrufe",
+      "by_action": "Aufschlüsselung nach Funktion",
+      "by_model": "Aufschlüsselung nach Modell",
+      "pricing_note": "Referenzpreise: gemini-2.5-flash $0.15/1M Input, $0.60/1M Output.",
+      "system_title": "System",
+      "db_size": "Datenbankgröße",
+      "log_size": "Log-Größe",
+      "log_level": "Log-Level"
    }
  },
  "expiry": {
@@ -761,6 +761,24 @@
      "card_title": "♻️ Zero-waste tips",
      "card_hint": "During cooking, show tips on how to reuse scraps generated in each step (peels, cooking water, etc.). Disabled by default.",
      "label": "Show tips during cooking"
+    },
+    "info": {
+      "tab": "Info",
+      "ai_title": "Gemini AI — Token Usage",
+      "ai_hint": "Monthly consumption and estimated cost for the current API key.",
+      "loading": "Loading…",
+      "total_tokens": "Total tokens",
+      "est_cost": "Est. cost",
+      "input_tok": "Input tokens",
+      "output_tok": "Output tokens",
+      "ai_calls": "AI calls",
+      "by_action": "Breakdown by function",
+      "by_model": "Breakdown by model",
+      "pricing_note": "Reference pricing: gemini-2.5-flash $0.15/1M input, $0.60/1M output.",
+      "system_title": "System",
+      "db_size": "Database size",
+      "log_size": "Log size",
+      "log_level": "Log level"
    }
  },
  "expiry": {
@@ -761,6 +761,24 @@
      "card_title": "♻️ Suggerimenti zero-waste",
      "card_hint": "Durante la cottura, mostra consigli su come riutilizzare gli scarti prodotti in ogni passo (bucce, acqua di cottura, ecc.). Disattivo per impostazione predefinita.",
      "label": "Mostra suggerimenti durante la cottura"
+    },
+    "info": {
+      "tab": "Info",
+      "ai_title": "Gemini AI — Utilizzo Token",
+      "ai_hint": "Consumo mensile e costo stimato per la chiave API corrente.",
+      "loading": "Caricamento…",
+      "total_tokens": "Token totali",
+      "est_cost": "Costo stimato",
+      "input_tok": "Token input",
+      "output_tok": "Token output",
+      "ai_calls": "Chiamate AI",
+      "by_action": "Dettaglio per funzione",
+      "by_model": "Dettaglio per modello",
+      "pricing_note": "Prezzi di riferimento: gemini-2.5-flash $0.15/1M input, $0.60/1M output.",
+      "system_title": "Sistema",
+      "db_size": "Dimensione database",
+      "log_size": "Dimensione log",
+      "log_level": "Livello di log"
    }
  },
  "expiry": {