$type = $m['meter_type'] ?? 'Warmwasser';
            $cost = $this->AddMeterToPDFRow($m, $tariffs, $from, $to, $type);
            $html .= $cost['row'];
            $total += $cost['value'];
        }

        $html .= "</table><h3>Gesamtsumme: " . number_format($total, 2) . " CHF</h3>";
        $pdf->writeHTML($html);
    }

        

        IPS_LogMessage('Abrechnung', '✅ PDF-Daten fertiggestellt');
        return $pdf->Output('Abrechnung.pdf', 'S');
        
    } catch (Throwable $e) {
        IPS_LogMessage('Abrechnung', '💥 Exception in TCPDF: ' . $e->getMessage());
        return false;
    }
}


    private function AddMeterToPDF($pdf, $meter, $tariffs, $from, $to, $type)
    {
        $start = $this->GetValueAt($meter['var_consumption'], $from);
        $end   = $this->GetValueAt($meter['var_consumption'], $to);
        if ($start === null || $end === null) return 0;

        $diff  = max(0, $end - $start);
        $tariffRp = $this->GetTariff($tariffs, $type, $from, $to);
        $cost  = ($tariffRp / 100) * $diff;

        $pdf->writeHTML("
            <tr>
                <td>{$meter['name']}</td>
                <td>$type</td>
                <td>$start</td>
                <td>$end</td>
                <td>$diff</td>
                <td>$tariffRp</td>
                <td>" . number_format($cost, 2) . "</td>
            </tr>", false, false, false, false, '');

        return $cost;
    }

    private function GetTariff(array $tariffs, string $type, int $from, int $to): float
    {
        foreach ($tariffs as $t) {
            $start = strtotime($t['start']);
            $end   = strtotime($t['end']);
            if ($from >= $start && $to <= $end && strtolower($t['unit_type']) == strtolower($type)) {
                return floatval($t['price']);
            }
        }
        // Kein passender Tarif gefunden
        return 0.0;
    }

private function GetValueAt(int $varId, int $timestamp, bool $nearestAfter = true)
{
    $archiveID = @IPS_GetInstanceListByModuleID('{43192F0B-135B-4CE7-A0A7-1475603F3060}')[0];
    if (!$archiveID || !IPS_VariableExists($varId)) {
        IPS_LogMessage('Abrechnung', "❌ Variable $varId oder Archiv $archiveID nicht gefunden");
        return null;
    }

    $maxDays = 365;     // maximal 1 Jahr suchen
    $stepDays = 30;     // in 30-Tage-Blöcken durchsuchen
    $valueFound = null;

    if ($nearestAfter) {
        // 🔹 Suche den ersten Wert NACH dem gewünschten Zeitpunkt
        for ($offset = 0; $offset < $maxDays; $offset += $stepDays) {
            $from = $timestamp + $offset * 86400;
            $to   = $from + $stepDays * 86400;
            $values = @AC_GetLoggedValues($archiveID, $varId, $from, $to, 0);
            if (!empty($values)) {
                // ersten Wert nach Timestamp nehmen
                foreach ($values as $v) {
                    if ($v['TimeStamp'] >= $timestamp) {
                        $valueFound = floatval($v['Value']);
                        break 2;
                    }
                }
            }
        }
    } else {
        // 🔹 Suche den letzten Wert VOR dem gewünschten Zeitpunkt
        for ($offset = 0; $offset < $maxDays; $offset += $stepDays) {
            $from = $timestamp - ($offset + $stepDays) * 86400;
            $to   = $timestamp - $offset * 86400;
            $values = @AC_GetLoggedValues($archiveID, $varId, $from, $to, 0);
            if (!empty($values)) {
                // letzten Wert vor Timestamp nehmen
                $last = null;
                foreach ($values as $v) {
                    if ($v['TimeStamp'] <= $timestamp) {
                        $last = $v;
                    } else {
                        break;
                    }
                }
                if ($last !== null) {
                    $valueFound = floatval($last['Value']);
                    break;
                }
            }
        }
    }

    // 🔹 Falls nichts im Archiv: aktuellen Variablenwert nehmen
    if ($valueFound === null) {
        $fallback = floatval(GetValue($varId));
        IPS_LogMessage('Abrechnung', "⚠ Kein Archivwert für $varId gefunden – nutze aktuellen Wert ($fallback)");
        return $fallback;
    }

    return $valueFound;
}


private function AddMeterToPDFRow($meter, $tariffs, $from, $to, $type)
{
    $rows = '';
    $totalCost = 0.0;
    $varId = $meter['var_consumption'];

    IPS_LogMessage('Abrechnung', "🔧 [AddMeterToPDFRow] Starte für '{$meter['name']}' (Typ: {$type}) von " . date('d.m.Y H:i', $from) . " bis " . date('d.m.Y H:i', $to));

    if (!IPS_VariableExists($varId)) {
        IPS_LogMessage('Abrechnung', "❌ Variable {$varId} für {$meter['name']} nicht gefunden");
        return ['row' => '', 'value' => 0];
    }

    // Zeitzone setzen, um strtotime()-Abweichungen zu vermeiden
    date_default_timezone_set('Europe/Zurich');

    // 1️⃣ Relevante Tarife nach Typ filtern
    $filteredTariffs = array_filter($tariffs, function ($t) use ($type) {
        return strtolower(trim($t['unit_type'] ?? '')) === strtolower(trim($type));
    });

    if (empty($filteredTariffs)) {
        IPS_LogMessage('Abrechnung', "⚠ Keine passenden Tarife für {$type} gefunden");
        return ['row' => '', 'value' => 0];
    }

    // 2️⃣ Zeitstempel konvertieren, JSON-Objekte erkennen & sortieren
    foreach ($filteredTariffs as &$t) {
        // JSON-Fix: Start/Ende evtl. verschachtelt
        if (is_string($t['start']) && str_starts_with(trim($t['start']), '{')) {
            $s = json_decode($t['start'], true);
            if (is_array($s)) {
                $t['start'] = sprintf('%04d-%02d-%02d 00:00:00', $s['year'], $s['month'], $s['day']);
            }
        }
        if (is_string($t['end']) && str_starts_with(trim($t['end']), '{')) {
            $e = json_decode($t['end'], true);
            if (is_array($e)) {
                $t['end'] = sprintf('%04d-%02d-%02d 23:59:59', $e['year'], $e['month'], $e['day']);
            }
        }

        $t['start_ts'] = is_numeric($t['start']) ? intval($t['start']) : strtotime($t['start']);
        $t['end_ts']   = is_numeric($t['end'])   ? intval($t['end'])   : strtotime($t['end']);

        if (!$t['start_ts'] || !$t['end_ts']) {
            IPS_LogMessage('Abrechnung', "⚠ Ungültiger Tarifzeitraum: " . json_encode($t));
        } else {
            IPS_LogMessage('Abrechnung', sprintf(
                "   🕓 Tarif gültig von %s bis %s @ %.3f Rp",
                date('d.m.Y H:i', $t['start_ts']),
                date('d.m.Y H:i', $t['end_ts']),
                floatval($t['price'])
            ));
        }
    }
    unset($t);
    usort($filteredTariffs, fn($a, $b) => $a['start_ts'] <=> $b['start_ts']);

    // 3️⃣ Abrechnungslogik
    $currentStart = $from;
    $segmentIndex = 1;

    while ($currentStart < $to) {
        IPS_LogMessage('Abrechnung', "➡️ Segment {$segmentIndex} Startzeit: " . date('d.m.Y H:i', $currentStart));

        // 🔹 Aktiven Tarif bestimmen (FIX: <= auch am Ende erlaubt)
        $activeTariff = null;