feat: add reset traffic toggle on tariff switch

- Add reset_traffic parameter to previewTariffSwitch and switchTariff API calls
- Add reset_traffic_available/reset_traffic_default fields to TariffSwitchPreview type
- Add toggle switch in tariff switch preview modal (shown when backend enables it)
- Initialize toggle from server default (reset_traffic_default)
- Pass reset_traffic flag on switch execution
- Add translations for all 4 locales (ru, en, zh, fa)

src/api/subscription.ts

@@ -345,6 +345,7 @@ export const subscriptionApi = {
   // Preview tariff switch cost
   previewTariffSwitch: async (
     tariffId: number,
+    resetTraffic?: boolean,
   ): Promise<{
     can_switch: boolean;
     current_tariff_id: number | null;
@@ -364,10 +365,14 @@ export const subscriptionApi = {
     base_upgrade_cost_kopeks?: number;
     discount_percent?: number;
     discount_kopeks?: number;
+    // Traffic reset on switch
+    reset_traffic_available?: boolean;
+    reset_traffic_default?: boolean;
   }> => {
     const response = await apiClient.post('/cabinet/subscription/tariff/switch/preview', {
       tariff_id: tariffId,
-      period_days: 30, // Default period for switch
+      period_days: 30,
+      ...(resetTraffic !== undefined && { reset_traffic: resetTraffic }),
     });
     return response.data;
   },
@@ -375,6 +380,7 @@ export const subscriptionApi = {
   // Switch to a different tariff
   switchTariff: async (
     tariffId: number,
+    resetTraffic?: boolean,
   ): Promise<{
     success: boolean;
     message: string;
@@ -389,6 +395,7 @@ export const subscriptionApi = {
     const response = await apiClient.post('/cabinet/subscription/tariff/switch', {
       tariff_id: tariffId,
       period_days: 30,
+      ...(resetTraffic !== undefined && { reset_traffic: resetTraffic }),
     });
     return response.data;
   },

src/locales/en.json

@@ -483,7 +483,9 @@
       "switched": "Tariff switched",
       "notEnoughBalance": "Insufficient balance",
       "dailyPayment": "Daily payment",
-      "dailyChargeDescription": "Charged daily from your balance"
+      "dailyChargeDescription": "Charged daily from your balance",
+      "resetTraffic": "Reset traffic",
+      "resetTrafficHint": "Reset used traffic when switching tariff"
     },
     "switchTraffic": {
       "title": "Change Traffic",

src/locales/fa.json

@@ -378,7 +378,9 @@
       "remainingDays": "روزهای باقی‌مانده",
       "switch": "تغییر",
       "title": "تغییر تعرفه",
-      "upgradeCost": "هزینه ارتقا"
+      "upgradeCost": "هزینه ارتقا",
+      "resetTraffic": "بازنشانی ترافیک",
+      "resetTrafficHint": "بازنشانی ترافیک مصرفی هنگام تغییر تعرفه"
     },
     "promoGroup": {
       "yourGroup": "گروه شما: {{name}}",

src/locales/ru.json

@@ -506,7 +506,9 @@
       "switched": "Тариф изменён",
       "notEnoughBalance": "Недостаточно средств",
       "dailyPayment": "Оплата за день",
-      "dailyChargeDescription": "Списывается ежедневно с баланса"
+      "dailyChargeDescription": "Списывается ежедневно с баланса",
+      "resetTraffic": "Сбросить трафик",
+      "resetTrafficHint": "Обнулить использованный трафик при смене тарифа"
     },
     "switchTraffic": {
       "title": "Изменить трафик",

src/locales/zh.json

@@ -378,7 +378,9 @@
       "remainingDays": "剩余天数",
       "switch": "切换",
       "title": "切换套餐",
-      "upgradeCost": "升级费用"
+      "upgradeCost": "升级费用",
+      "resetTraffic": "重置流量",
+      "resetTrafficHint": "切换套餐时重置已使用流量"
     },
     "promoGroup": {
       "yourGroup": "您的组：{{name}}",

src/pages/SubscriptionPurchase.tsx

@@ -128,12 +128,14 @@ export default function SubscriptionPurchase() {
 
   // Tariff switch
   const [switchTariffId, setSwitchTariffId] = useState<number | null>(null);
+  const [resetTrafficOnSwitch, setResetTrafficOnSwitch] = useState(false);
 
   // Auto-close all modals on success notification
   const handleCloseAllModals = () => {
     setShowPurchaseForm(false);
     setShowTariffPurchase(false);
     setSwitchTariffId(null);
+    setResetTrafficOnSwitch(false);
     setSelectedTariff(null);
     setSelectedTariffPeriod(null);
   };
@@ -230,13 +232,21 @@ export default function SubscriptionPurchase() {
     enabled: !!switchTariffId,
   });
 
+  // Initialize reset traffic toggle from server default
+  useEffect(() => {
+    if (switchPreview?.reset_traffic_default !== undefined) {
+      setResetTrafficOnSwitch(switchPreview.reset_traffic_default);
+    }
+  }, [switchPreview?.reset_traffic_default]);
+
   // Tariff switch mutation
   const switchTariffMutation = useMutation({
-    mutationFn: (tariffId: number) => subscriptionApi.switchTariff(tariffId),
+    mutationFn: (tariffId: number) => subscriptionApi.switchTariff(tariffId, resetTrafficOnSwitch),
     onSuccess: () => {
       queryClient.invalidateQueries({ queryKey: ['subscription'] });
       queryClient.invalidateQueries({ queryKey: ['purchase-options'] });
       setSwitchTariffId(null);
+      setResetTrafficOnSwitch(false);
       navigate('/subscription', { replace: true });
     },
     onError: (error: unknown) => {
@@ -250,6 +260,7 @@ export default function SubscriptionPurchase() {
           const targetTariff = tariffs.find((tariff) => tariff.id === switchTariffId);
           if (targetTariff) {
             setSwitchTariffId(null);
+            setResetTrafficOnSwitch(false);
             setSelectedTariff(targetTariff);
             setSelectedTariffPeriod(targetTariff.periods[0] || null);
             setShowTariffPurchase(true);
@@ -598,6 +609,35 @@ export default function SubscriptionPurchase() {
                         </div>
                       </div>
 
+                      {/* Reset traffic toggle */}
+                      {switchPreview.reset_traffic_available && (
+                        <label className="flex cursor-pointer items-center justify-between rounded-lg border border-dark-700/50 bg-dark-800/50 px-3 py-2.5">
+                          <div>
+                            <div className="text-sm font-medium text-dark-100">
+                              {t('subscription.switchTariff.resetTraffic')}
+                            </div>
+                            <div className="text-xs text-dark-400">
+                              {t('subscription.switchTariff.resetTrafficHint')}
+                            </div>
+                          </div>
+                          <button
+                            type="button"
+                            role="switch"
+                            aria-checked={resetTrafficOnSwitch}
+                            onClick={() => setResetTrafficOnSwitch((prev) => !prev)}
+                            className={`relative h-6 w-11 flex-shrink-0 rounded-full transition-colors duration-200 ${
+                              resetTrafficOnSwitch ? 'bg-accent-500' : 'bg-dark-600'
+                            }`}
+                          >
+                            <span
+                              className={`absolute left-0.5 top-0.5 h-5 w-5 rounded-full bg-white shadow transition-transform duration-200 ${
+                                resetTrafficOnSwitch ? 'translate-x-5' : 'translate-x-0'
+                              }`}
+                            />
+                          </button>
+                        </label>
+                      )}
+
                       {!switchPreview.has_enough_balance &&
                         switchPreview.upgrade_cost_kopeks > 0 && (
                           <InsufficientBalancePrompt

src/types/index.ts

@@ -143,6 +143,9 @@ export interface TariffSwitchPreview {
   base_upgrade_cost_kopeks?: number;
   discount_percent?: number;
   discount_kopeks?: number;
+  // Traffic reset on switch
+  reset_traffic_available?: boolean;
+  reset_traffic_default?: boolean;
 }
 
 export interface RenewalOption {