fix(promocode): correct activation UX, error mapping and validity dates

Map promocode errors by stable backend code (detail.code) instead of brittle English
substring matching, so previously-unmapped codes (active_discount_exists, daily_limit,
no_subscription_for_days, trial_*, etc.) show the right message instead of 'server error';
added the missing keys to all 4 locales.

valid_until now anchors to end-of-day in the admin's LOCAL timezone on both create AND
edit read-back, so codes no longer expire at the start of the day and editing no longer
drifts the date forward for negative-offset admins.

Allow 0-hour discount ('until first purchase'). Route user-facing discount deactivation
to the endpoint that rolls back promocode usage when the discount came from a promocode,
and parse the structured {code,message} error.

src/components/PromoOffersSection.tsx

@@ -118,9 +118,21 @@ export default function PromoOffersSection({ className = '' }: PromoOffersSectio
     },
   });
 
-  // Deactivate discount mutation
+  // Deactivate discount mutation.
+  // A discount granted by a PROMOCODE must be turned off via the dedicated route
+  // (POST /cabinet/promocode/deactivate-discount), which also rolls back the promocode
+  // usage (deletes the PromoCodeUse, decrements current_uses, strips the promo group) so
+  // the user can re-activate it later. The plain clearActiveDiscount route only zeroes
+  // the discount fields and is correct for admin/offer-sourced discounts.
   const deactivateMutation = useMutation({
-    mutationFn: promoApi.clearActiveDiscount,
+    mutationFn: async () => {
+      const source = activeDiscount?.source ?? '';
+      if (source.startsWith('promocode:')) {
+        await promoApi.deactivateDiscount();
+      } else {
+        await promoApi.clearActiveDiscount();
+      }
+    },
     onSuccess: () => {
       queryClient.invalidateQueries({ queryKey: ['active-discount'] });
       queryClient.invalidateQueries({ queryKey: ['promo-offers'] });
@@ -131,8 +143,14 @@ export default function PromoOffersSection({ className = '' }: PromoOffersSectio
       setTimeout(() => setSuccessMessage(null), 5000);
     },
     onError: (error: unknown) => {
-      const axiosErr = error as { response?: { data?: { detail?: string } } };
+      // detail may be a plain string (clearActiveDiscount route) or a structured
-      setErrorMessage(axiosErr.response?.data?.detail || t('promo.deactivate.error'));
+      // { code, message } object (deactivate-discount route). Handle both.
+      const axiosErr = error as {
+        response?: { data?: { detail?: string | { message?: string } } };
+      };
+      const detail = axiosErr.response?.data?.detail;
+      const message = typeof detail === 'string' ? detail : detail?.message;
+      setErrorMessage(message || t('promo.deactivate.error'));
 
       setTimeout(() => setErrorMessage(null), 5000);
     },

src/locales/en.json

@@ -787,6 +787,13 @@
         "not_yet_valid": "Promo code is not yet active",
         "used": "Promo code has already been used",
         "already_used_by_user": "You have already used this promo code",
+        "active_discount_exists": "You already have an active discount. Deactivate it first.",
+        "no_subscription_for_days": "This promo code requires an active or expired subscription",
+        "subscription_not_found": "Subscription not found",
+        "not_first_purchase": "This promo code is only available for your first purchase",
+        "daily_limit": "Too many promo code activations today",
+        "trial_subscription_exists": "You already have a subscription, so this trial code can't be applied",
+        "trial_provisioning_failed": "Couldn't provision the trial right now, please try again later",
         "user_not_found": "User not found",
         "server_error": "Server error"
       },

src/locales/fa.json

@@ -674,6 +674,13 @@
         "not_yet_valid": "کد تخفیف هنوز فعال نشده",
         "used": "کد تخفیف قبلاً استفاده شده",
         "already_used_by_user": "شما قبلاً از این کد استفاده کرده‌اید",
+        "active_discount_exists": "شما در حال حاضر یک تخفیف فعال دارید. ابتدا آن را غیرفعال کنید.",
+        "no_subscription_for_days": "این کد تخفیف به اشتراک فعال یا منقضی‌شده نیاز دارد",
+        "subscription_not_found": "اشتراک یافت نشد",
+        "not_first_purchase": "این کد تخفیف فقط برای اولین خرید در دسترس است",
+        "daily_limit": "تعداد فعال‌سازی کد تخفیف امروز بیش از حد است",
+        "trial_subscription_exists": "شما در حال حاضر اشتراک دارید، بنابراین این کد آزمایشی قابل اعمال نیست",
+        "trial_provisioning_failed": "در حال حاضر امکان فعال‌سازی نسخه آزمایشی نیست، لطفاً بعداً تلاش کنید",
         "user_not_found": "کاربر یافت نشد",
         "server_error": "خطای سرور"
       },

src/locales/ru.json

@@ -816,6 +816,13 @@
         "not_yet_valid": "Промокод ещё не начал действовать",
         "used": "Промокод уже использован",
         "already_used_by_user": "Вы уже использовали этот промокод",
+        "active_discount_exists": "У вас уже есть активная скидка. Сначала отключите её.",
+        "no_subscription_for_days": "Для этого промокода нужна активная или истёкшая подписка",
+        "subscription_not_found": "Подписка не найдена",
+        "not_first_purchase": "Промокод доступен только для первой покупки",
+        "daily_limit": "Слишком много активаций промокодов за сегодня",
+        "trial_subscription_exists": "У вас уже есть подписка, поэтому триал-промокод применить нельзя",
+        "trial_provisioning_failed": "Не удалось выдать триал прямо сейчас, попробуйте позже",
         "user_not_found": "Пользователь не найден",
         "server_error": "Ошибка сервера"
       },

src/locales/zh.json

@@ -674,6 +674,13 @@
         "not_yet_valid": "优惠码尚未生效",
         "used": "优惠码已被使用",
         "already_used_by_user": "您已使用过此优惠码",
+        "active_discount_exists": "您已有一个生效中的折扣，请先停用它。",
+        "no_subscription_for_days": "此优惠码需要有效或已过期的订阅",
+        "subscription_not_found": "未找到订阅",
+        "not_first_purchase": "此优惠码仅限首次购买使用",
+        "daily_limit": "今日优惠码激活次数过多",
+        "trial_subscription_exists": "您已有订阅，因此无法使用此试用优惠码",
+        "trial_provisioning_failed": "暂时无法开通试用，请稍后再试",
         "user_not_found": "用户不存在",
         "server_error": "服务器错误"
       },

src/pages/AdminPromocodeCreate.tsx

@@ -16,6 +16,16 @@ import { tariffsApi } from '../api/tariffs';
 import { usePlatform } from '../platform/hooks/usePlatform';
 import { BackIcon, RefreshIcon } from '@/components/icons';
 
+// valid_until is created as end-of-day in the admin's LOCAL tz, then stored/returned
+// as a UTC instant. Reading the picker back must convert UTC -> local date, otherwise
+// negative-offset admins see tomorrow's date and re-saving drifts the expiry forward a
+// day each time. (Mirror of DateField's local toISO; must NOT slice the raw UTC string.)
+const utcInstantToLocalDateInput = (iso: string): string => {
+  const d = new Date(iso);
+  const pad = (n: number) => String(n).padStart(2, '0');
+  return `${d.getFullYear()}-${pad(d.getMonth() + 1)}-${pad(d.getDate())}`;
+};
+
 export default function AdminPromocodeCreate() {
   const { t } = useTranslation();
   const navigate = useNavigate();
@@ -76,7 +86,7 @@ export default function AdminPromocodeCreate() {
       setMaxUses(data.max_uses || 1);
       setIsActive(data.is_active ?? true);
       setFirstPurchaseOnly(data.first_purchase_only || false);
-      setValidUntil(data.valid_until ? data.valid_until.split('T')[0] : '');
+      setValidUntil(data.valid_until ? utcInstantToLocalDateInput(data.valid_until) : '');
       setPromoGroupId(data.promo_group_id || null);
       setTariffId(data.tariff_id || null);
       return data;
@@ -120,7 +130,12 @@ export default function AdminPromocodeCreate() {
       max_uses: maxUsesValue,
       is_active: isActive,
       first_purchase_only: firstPurchaseOnly,
-      valid_until: validUntil ? new Date(validUntil).toISOString() : null,
+      // The picker yields a date-only 'YYYY-MM-DD'. A promo "valid until D" must
+      // stay valid through the WHOLE of day D, so anchor to end-of-day in the
+      // admin's local timezone. `new Date('YYYY-MM-DD')` parses as UTC midnight
+      // (the START of the day) — for a GMT+3 admin that made a code picked for
+      // "today" already expired by 3am, surfacing as a bogus "expired" error.
+      valid_until: validUntil ? new Date(`${validUntil}T23:59:59`).toISOString() : null,
       promo_group_id: type === 'promo_group' ? promoGroupId : null,
       ...(type === 'trial_subscription' && tariffId ? { tariff_id: tariffId } : {}),
     };
@@ -145,7 +160,8 @@ export default function AdminPromocodeCreate() {
     if ((type === 'subscription_days' || type === 'trial_subscription') && daysValue <= 0)
       return false;
     if (type === 'promo_group' && !promoGroupId) return false;
-    if (type === 'discount' && (balanceValue <= 0 || balanceValue > 100 || daysValue <= 0))
+    // For discount, validity hours of 0 = "until first purchase" (perpetual) — allowed.
+    if (type === 'discount' && (balanceValue <= 0 || balanceValue > 100 || daysValue < 0))
       return false;
     return true;
   };
@@ -410,7 +426,7 @@ export default function AdminPromocodeCreate() {
                     }
                   }}
                   className="input w-32"
-                  min={1}
+                  min={0}
                   placeholder="0"
                 />
                 <span className="text-dark-400">{t('admin.promocodes.form.hours')}</span>

src/pages/Balance.tsx

@@ -159,22 +159,33 @@ export default function Balance() {
         queryClient.invalidateQueries({ queryKey: ['subscriptions-list'] });
       }
     } catch (error: unknown) {
-      const axiosError = error as { response?: { data?: { detail?: string } } };
+      // Backend returns a structured error: detail = { code, message }. We map
-      const errorDetail = axiosError.response?.data?.detail || 'server_error';
+      // the stable machine code to a localized string. (The old contract
-      const detail = errorDetail.toLowerCase();
+      // substring-matched English prose and silently degraded every unmapped
-      const errorKey = detail.includes('not found')
+      // code — active_discount_exists, daily_limit, … — to "server error".)
-        ? 'not_found'
+      const axiosError = error as {
-        : detail.includes('deactivated')
+        response?: { data?: { detail?: { code?: string } | string } };
-          ? 'inactive'
+      };
-          : detail.includes('not yet active')
+      const detail = axiosError.response?.data?.detail;
-            ? 'not_yet_valid'
+      const code = typeof detail === 'object' && detail ? detail.code : undefined;
-            : detail.includes('expired')
+      const knownErrorKeys = [
-              ? 'expired'
+        'not_found',
-              : detail.includes('fully used')
+        'expired',
-                ? 'used'
+        'inactive',
-                : detail.includes('already used')
+        'not_yet_valid',
-                  ? 'already_used_by_user'
+        'used',
-                  : 'server_error';
+        'already_used_by_user',
+        'active_discount_exists',
+        'no_subscription_for_days',
+        'subscription_not_found',
+        'not_first_purchase',
+        'daily_limit',
+        'trial_subscription_exists',
+        'trial_provisioning_failed',
+        'user_not_found',
+        'server_error',
+      ];
+      const errorKey = code && knownErrorKeys.includes(code) ? code : 'server_error';
       setPromocodeError(t(`balance.promocode.errors.${errorKey}`));
       setPromoSelectSubs(null);
       setPromoSelectCode(null);