/**
     * Renew VPS Service
     */
    public function renew(Request $request)
    {
        try {
            $user = customer();
            if (!$user) {
                return redirect()->route('user.login')->with('error', __('Vui lòng đăng nhập.'));
            }

            // 1. Validate Input
            $validator = FacadesValidator::make($request->all(), [
                'product_id' => 'required|string',
                'plan' => 'required',
                'months' => 'nullable|integer|min:2|max:60'
            ]);

            if ($validator->fails()) {
                return redirect()->back()->withErrors($validator)->withInput()->with('error', __('Dữ liệu không hợp lệ.'));
            }

            $vmware_id = $this->sanitizeInput($request->product_id);
            $plan = $request->input('plan');
            $months = $plan === 'other' ? (int)$request->input('months') : (int)$plan;

            if ($months < 2) {
                return redirect()->back()->with('error', __('Thời hạn gia hạn tối thiểu là 2 tháng.'));
            }

            // 2. Find Service & Verify Ownership
            $vm = ModuleVmware::where('vmware_id', $vmware_id)
                ->where('customer_id', $user->id)
                ->first();

            if (!$vm) {
                return redirect()->back()->with('error', __('Không tìm thấy dịch vụ hoặc bạn không có quyền truy cập.'));
            }

            // 3. Calculate Price based on Original Order/InvoiceItem
            // Strategy: Find the InvoiceItem from the Order associated with this VM.
            // If multiple items, try to match type VPS (4).
            
            $order = Order::find($vm->order_id);
            if (!$order) {
                 // Fallback if order missing (rare)
                 // Try finding by invoice_id if stored on VM? ModuleVmware has next_invoice but not current_invoice.
                 return redirect()->back()->with('error', __('Không tìm thấy đơn hàng gốc của dịch vụ này.'));
            }

            // Find InvoiceItem
            // Order has relationship to Invoice (order->invoice)
            // Or Order has orderItems (which are InvoiceItems)
            $invoiceItem = null;
            if ($order->invoice) {
                // Try finding item in the invoice related to this order 
                // Note: The modal uses $invoice->invoiceItem->first(). We should try to be specific.
                // We don't have a direct link from ModuleVmware to InvoiceItem.
                // But ModuleVmware links to Order, which links to items.
                // Let's take the first item of type 4 (VPS) from the order's invoice.
               $invoiceItem = $order->invoice->invoiceItem->where('type_id', 4)->first();
                if (!$invoiceItem) {
                    $invoiceItem = $order->invoice->invoiceItem->first();
                }
            }

            if (!$invoiceItem) {
                 // Extreme fallback or failure
                 return redirect()->back()->with('error', __('Không tìm thấy thông tin giá của dịch vụ.'));
            }

            // Calculate Unit Price (Monthly)
            // 'amount' in InvoiceItem is total price for 'months' duration.
            $billing_months = $invoiceItem->months > 0 ? $invoiceItem->months : 1; 
            if ($invoiceItem->amount <= 0) {
                 // If amount is 0 (free?), unit price is 0.
                 $base_unit_price = 0;
            } else {
                 $base_unit_price = $invoiceItem->amount / $billing_months;
            }

            // Calculate Addons Unit Price
            $addons_unit_price = 0;
            if ($invoiceItem->addons && $invoiceItem->addons->count() > 0) {
                foreach ($invoiceItem->addons as $addonPivot) {
                    // Try to find price. Assuming Addon model has current price.
                    // Ideally we should use the price stored in pivot if available, but pivot structure is unknown.
                    // We'll use the Addon catalog price as fallback or primary if pivot doesn't store it.
                    // $addonPivot->addonItems returns the Addon model.
                    if ($addonPivot->addonItems) {
                         $addons_unit_price += $addonPivot->addonItems->price;
                    }
                }
            }

            $total_unit_price = $base_unit_price + $addons_unit_price;
            $total_cost = $total_unit_price * $months;

            // 4. Check Balance
            if ($user->credit < $total_cost) {
                return redirect()->back()->with('error', __('Số dư tài khoản không đủ để gia hạn (Cần: :amount). Vui lòng nạp thêm tiền.', ['amount' => number_format($total_cost) . ' VNĐ']));
            }

            // 5. Process Renewal
            DB::beginTransaction();
            try {
                // Deduct Credit
                $user->decrement('credit', $total_cost);

                // Create Renewal Invoice (Paid) - Optional but good for history
                $newInvoice = Invoice::create([
                    'customer_id' => $user->id,
                    'status' => 1, // Paid
                    'date' => now(),
                    'due_date' => now(),
                    'total' => $total_cost,
                    'payment_method' => 'credit_balance', // or similar
                    'description' => "Gia hạn dịch vụ VPS #{$vm->name} ({$months} tháng)"
                ]);

                // Update VM Expiry
                // If current expiry is in the past, renew from NOW? Or from expiry?
                // Usually from expiry if it's recent grace period. If long expired, maybe from now.
                // Let's simply add to next_due_date.
                
                $current_due = $vm->next_due_date ? \Carbon\Carbon::parse($vm->next_due_date) : now();
                if ($current_due->isPast()) {
                     // If expired, maybe we should start from today? 
                     // Or just extend the gap. User usually pays for the gap. 
                     // Let's extend from current_due to maintain billing cycle.
                }
                $new_due_date = $current_due->copy()->addMonths($months);

                $vm->update([
                    'next_due_date' => $new_due_date,
                    'status' => 1, // Ensure active if it was suspended
                ]);

                // Log or Notify (Optional)
                
                DB::commit();
                
                 // Clear cache
                Cache::forget("vm_info_{$vm->vmware_id}");

                return redirect()->back()->with('success', __('Gia hạn dịch vụ thành công! Hạn sử dụng mới: :date', ['date' => $new_due_date->format('d/m/Y')]));

            } catch (\Exception $e) {
                DB::rollBack();
                throw $e;
            }

        } catch (\Exception $e) {
            Log::error("Error renewing VM: " . $e->getMessage());
            return redirect()->back()->with('error', __('Có lỗi xảy ra khi gia hạn dịch vụ. Vui lòng thử lại sau.'));
        }
    }