feat(events): harden registration checkout lifecycle

.env.development.example

@@ -27,6 +27,9 @@ SMS_PAYMENT_STATUS_TEMPLATE_ID=
 
 FRONTEND_ROOT=http://localhost:8080
 FRONTEND_CALLBACK_URL=http://localhost:8080/payments/result
+PAYMENT_VERIFICATION_GRACE_SECONDS=1800
+PAYMENT_VERIFICATION_MAX_ATTEMPTS=6
+PAYMENT_VERIFICATION_DISPATCH_LEASE_SECONDS=900
 GOOGLE_OAUTH_REDIRECT_URI=http://127.0.0.1:8000/api/auth/oauth/google/callback
 GOOGLE_OAUTH_FRONTEND_CALLBACK_URL=http://localhost:8080/auth/google/callback
 

.env.example

@@ -58,6 +58,9 @@ CSRF_COOKIE_SECURE=True
 SESSION_COOKIE_SECURE=True
 FRONTEND_ROOT=https://frontend.example.com
 FRONTEND_CALLBACK_URL=https://frontend.example.com/payments/result
+PAYMENT_VERIFICATION_GRACE_SECONDS=1800
+PAYMENT_VERIFICATION_MAX_ATTEMPTS=6
+PAYMENT_VERIFICATION_DISPATCH_LEASE_SECONDS=900
 
 # SSE Notifications
 NOTIFICATIONS_ENABLED=True

apps/content/management/commands/seed_mock_content.py

@@ -87,7 +87,7 @@ ABOUT_MOCK = {
     "members_intro": "با اعضایی آشنا شوید که برای ساختن تجربه‌های بهتر در انجمن همکاری می‌کنند.",
     "gallery_heading": "خاطرات انجمن",
     "gallery_intro": "تصاویری از گردهمایی‌ها، برنامه‌ها و لحظه‌هایی که کنار هم ساخته‌ایم.",
-    "past_events_heading": "رویدادهای برگزارشده",
+    "past_events_heading": "رویدادهای برگزار شده",
     "history_heading": "مسیر انجمن",
     "audience_heading": "برای چه کسانی؟",
     "year_events_heading": "لحظه‌های هر سال",

apps/events/admin.py

@@ -7,6 +7,7 @@ from core.templatetags.jalali import jdate
 from apps.events.models import Event, Registration
 from apps.events.resources import EventResource, RegistrationResource
 from apps.events.services import verify_registration_attendance
+from apps.events.checkout import cancel_event_checkouts
 
 
 @admin.register(Event)
@@ -79,8 +80,14 @@ class EventAdmin(BaseModelAdmin, ImportExportModelAdmin):
 
     @admin.action(description='Mark selected events as cancelled')
     def make_cancelled(self, request, queryset):
-        queryset.update(status=Event.StatusChoices.CANCELLED)
+        count = 0
-        self.message_user(request, f'Cancelled {queryset.count()} events.')
+        for event in queryset:
+            if event.status != Event.StatusChoices.CANCELLED:
+                event.status = Event.StatusChoices.CANCELLED
+                event.save(update_fields=['status'])
+                cancel_event_checkouts(event.pk)
+                count += 1
+        self.message_user(request, f'Cancelled {count} events.')
 
     @admin.action(description='Mark selected events as completed')
     def make_completed(self, request, queryset):
@@ -93,15 +100,27 @@ class EventAdmin(BaseModelAdmin, ImportExportModelAdmin):
             event.restore()
         self.message_user(request, f'Restored {queryset.count()} events.')
 
+    def save_model(self, request, obj, form, change):
+        previous_status = None
+        if change and obj.pk:
+            previous_status = Event.all_objects.filter(pk=obj.pk).values_list("status", flat=True).first()
+        super().save_model(request, obj, form, change)
+        if previous_status != Event.StatusChoices.CANCELLED and obj.status == Event.StatusChoices.CANCELLED:
+            cancel_event_checkouts(obj.pk)
+
 
 @admin.register(Registration)
 class RegistrationAdmin(BaseModelAdmin, ImportExportModelAdmin):
     resource_class = RegistrationResource
     list_display = (
-        'user', 'event', 'status', 'registered_at', 'ticket_id',
+        'user', 'event', 'status', 'registered_at', 'checkout_expires_at',
+        'cancellation_reason', 'ticket_id',
         'discount_code', 'discount_amount', 'final_price',
     )
-    list_filter = ('status', 'event', 'is_deleted', 'registered_at', SoftDeleteListFilter)
+    list_filter = (
+        'status', 'cancellation_reason', 'event', 'is_deleted', 'registered_at',
+        SoftDeleteListFilter,
+    )
     search_fields = (
         'user__username', 'user__email', 'user__first_name', 'user__last_name',
         'event__title', 'ticket_id',
@@ -109,13 +128,15 @@ class RegistrationAdmin(BaseModelAdmin, ImportExportModelAdmin):
     readonly_fields = (
         'ticket_id', 'registered_at', 'confirmation_notification_sent_at',
         'cancellation_notification_sent_at', 'discount_code', 'discount_amount',
-        'final_price', 'deleted_at', 'attendance_verified_at',
+        'final_price', 'checkout_started_at', 'checkout_expires_at',
+        'cancellation_reason', 'deleted_at', 'attendance_verified_at',
         'attendance_verified_by', 'attendance_verification_source',
     )
     fieldsets = (
         ('Registration Details', {'fields': (
             'user', 'event', 'status', 'registered_at', 'ticket_id',
             'confirmation_notification_sent_at', 'cancellation_notification_sent_at',
+            'checkout_started_at', 'checkout_expires_at', 'cancellation_reason',
         )}),
         ('Attendance verification', {'fields': (
             'attendance_verified_at', 'attendance_verified_by', 'attendance_verification_source',

apps/events/api/schemas.py

@@ -5,6 +5,8 @@ from ninja import ModelSchema, Schema
 from pydantic import field_validator
 from typing import Literal, Optional, List
 from datetime import datetime
+from django.db.models import Q
+from django.utils import timezone
 
 from apps.blog.api.schemas import AuthorSchema
 from apps.events.models import Event, Registration
@@ -85,7 +87,11 @@ class EventSchema(ModelSchema):
 
     @staticmethod
     def resolve_registration_count(obj):
-        return obj.registrations.filter(status__in=[Registration.StatusChoices.CONFIRMED, Registration.StatusChoices.ATTENDED]).count()
+        now = timezone.now()
+        return obj.registrations.filter(is_deleted=False).filter(
+            Q(status__in=[Registration.StatusChoices.CONFIRMED, Registration.StatusChoices.ATTENDED])
+            | Q(status=Registration.StatusChoices.PENDING, checkout_expires_at__gt=now)
+        ).count()
 
     @staticmethod
     def resolve_description_html(obj):
@@ -102,6 +108,7 @@ class EventListSchema(Schema):
     absolute_featured_image_thumbnail_url: Optional[str] = None
     absolute_featured_image_preview_url: Optional[str] = None
     event_type: str
+    address: Optional[str] = None
     start_time: datetime
     end_time: datetime
     registration_start_date: Optional[datetime] = None
@@ -133,7 +140,22 @@ class EventListSchema(Schema):
 
     @staticmethod
     def resolve_registration_count(obj):
-        return obj.registrations.filter(status__in=[Registration.StatusChoices.CONFIRMED, Registration.StatusChoices.ATTENDED]).count()
+        if hasattr(obj, "browse_registration_count"):
+            return obj.browse_registration_count
+        now = timezone.now()
+        return obj.registrations.filter(is_deleted=False).filter(
+            Q(status__in=[Registration.StatusChoices.CONFIRMED, Registration.StatusChoices.ATTENDED])
+            | Q(status=Registration.StatusChoices.PENDING, checkout_expires_at__gt=now)
+        ).count()
+
+
+class PaginatedEventBrowseSchema(Schema):
+    count: int
+    page: int
+    page_size: int
+    total_pages: int
+    price_ceiling: int
+    results: List[EventListSchema]
 
 class EventCreateSchema(Schema):
     """Payload for creating events via the API."""
@@ -185,6 +207,9 @@ class RegistrationSchema(ModelSchema):
             'id',
             'status',
             'registered_at',
+            'checkout_started_at',
+            'checkout_expires_at',
+            'cancellation_reason',
             'ticket_id',
             'discount_amount',
             'final_price',
@@ -326,9 +351,16 @@ class EventBriefSchema(Schema):
 class MyEventRegistrationOut(Schema):
     """Registration information as returned to authenticated users."""
     id: int
+    ticket_id: UUID
     created_at: datetime
     status: Literal["pending", "confirmed", "cancelled", "attended"]
     event: EventBriefSchema
+    checkout_state: Literal["none", "active", "legacy_pending", "expired", "unresolved", "cancelled"] = "none"
+    checkout_expires_at: Optional[datetime] = None
+    payment_id: Optional[int] = None
+    payment_status: Optional[Literal["initiated", "pending", "paid", "failed", "canceled"]] = None
+    refund_status: Optional[Literal["none", "pending", "succeeded", "manual_review"]] = None
+    can_resume: bool = False
 
 
 class PaginatedMyEventRegistrationsSchema(Schema):
@@ -340,6 +372,79 @@ class PaginatedMyEventRegistrationsSchema(Schema):
 
 class RegistrationStatusOut(Schema):
     is_registered: bool
+    checkout_state: Literal[
+        "none", "confirmed", "active", "legacy_pending", "expired", "unresolved", "cancelled"
+    ] = "none"
+    registration_id: Optional[int] = None
+    registration_status: Optional[str] = None
+    ticket_id: Optional[UUID] = None
+    checkout_expires_at: Optional[datetime] = None
+    payment_id: Optional[int] = None
+    payment_status: Optional[Literal["initiated", "pending", "paid", "failed", "canceled"]] = None
+    refund_status: Optional[Literal["none", "pending", "succeeded", "manual_review"]] = None
+    can_resume: bool = False
+    can_cancel: bool = False
+
+
+class RegistrationHubEventOut(Schema):
+    id: int
+    title: str
+    slug: str
+    description: str
+    event_type: str
+    address: Optional[str] = None
+    location: Optional[str] = None
+    start_time: datetime
+    end_time: datetime
+    registration_start_date: Optional[datetime] = None
+    registration_end_date: Optional[datetime] = None
+    capacity: Optional[int] = None
+    price: int
+    status: str
+    registration_count: int
+    image_url: Optional[str] = None
+    registration_success_markdown: Optional[str] = None
+
+
+class RegistrationHubRegistrationOut(Schema):
+    ticket_id: UUID
+    status: str
+    registered_at: datetime
+    checkout_started_at: Optional[datetime] = None
+    checkout_expires_at: Optional[datetime] = None
+    cancellation_reason: str = ""
+    final_price: Optional[int] = None
+    discount_amount: int = 0
+
+
+class RegistrationHubPaymentOut(Schema):
+    id: int
+    status: Literal["initiated", "pending", "paid", "failed", "canceled"]
+    verification_state: Literal[
+        "awaiting_verification", "checking", "retry_scheduled", "manual_review",
+        "verified", "failed", "canceled",
+    ]
+    refund_status: Literal["none", "pending", "succeeded", "manual_review"]
+    base_amount: int
+    discount_amount: int
+    amount: int
+    ref_id: Optional[str] = None
+    created_at: datetime
+    gateway_paid_at: Optional[datetime] = None
+
+
+class RegistrationHubOut(Schema):
+    state: Literal[
+        "ready", "active_checkout", "legacy_pending", "verification_pending",
+        "manual_review", "paid_success", "free_success", "failed", "cancelled",
+        "expired", "refund_pending", "refund_manual_review", "refund_succeeded",
+    ]
+    event: RegistrationHubEventOut
+    registration: Optional[RegistrationHubRegistrationOut] = None
+    payment: Optional[RegistrationHubPaymentOut] = None
+    can_register: bool = False
+    can_resume: bool = False
+    can_cancel: bool = False
 
 
 class RegistrationCreateSchema(Schema):

apps/events/api/views.py

@@ -1,7 +1,11 @@
 from django.conf import settings
 from django.core.files.base import ContentFile
 from django.shortcuts import get_object_or_404
-from django.db.models import Q, Case, When, IntegerField, F
+from django.db import transaction
+from datetime import date, datetime, time as datetime_time, timedelta
+from math import ceil
+
+from django.db.models import Q, Case, When, IntegerField, F, Count, Max
 from django.db.models.functions import Lower
 from django.utils.text import slugify
 from django.utils import timezone
@@ -17,6 +21,7 @@ from apps.events.api.schemas import (
     EventCreateSchema,
     EventGallerySchema,
     EventListSchema,
+    PaginatedEventBrowseSchema,
     EventSchema,
     EventUpdateSchema,
     MyEventRegistrationOut,
@@ -26,14 +31,22 @@ from apps.events.api.schemas import (
     RegistrationCreateSchema,
     RegistrationSchema,
     RegistrationStatusOut,
+    RegistrationHubOut,
     RegistrationStatusUpdateSchema,
 )
 from core.authentication import jwt_auth
 from apps.events.models import Event, Registration
+from apps.events.checkout import (
+    CHECKOUT_TIMEOUT,
+    cancel_event_checkouts,
+    expire_stale_registration_checkouts,
+    mark_checkout_cancelled,
+    queue_checkout_reconciliation,
+)
 from apps.gallery.models import Gallery
 from apps.gallery.tasks import process_uploaded_image
 from apps.notifications.services import notify_user
-from apps.payments.models import DiscountCode
+from apps.payments.models import DiscountCode, Payment
 from apps.users.tasks import send_critical_sms
 from core.api.schemas import ErrorSchema, MessageSchema
 
@@ -138,6 +151,143 @@ def list_events(
     events = queryset[offset:offset + limit]
     return events
 
+
+def _event_registration_open_query(now):
+    return (
+        Q(status=Event.StatusChoices.PUBLISHED)
+        & (Q(registration_start_date__isnull=True) | Q(registration_start_date__lte=now))
+        & (Q(registration_end_date__isnull=True) | Q(registration_end_date__gte=now))
+        & (Q(capacity__isnull=True) | Q(capacity__gt=F("browse_registration_count")))
+    )
+
+
+def _parse_browse_date(value: Optional[str], field_name: str):
+    if not value:
+        return None
+    try:
+        parsed = date.fromisoformat(value)
+    except ValueError as error:
+        raise HttpError(400, f"{field_name} باید به شکل YYYY-MM-DD باشد.") from error
+    if parsed.isoformat() != value:
+        raise HttpError(400, f"{field_name} باید به شکل YYYY-MM-DD باشد.")
+    return timezone.make_aware(
+        datetime.combine(parsed, datetime_time.min),
+        timezone.get_current_timezone(),
+    )
+
+
+@events_router.get("/browse/", response=PaginatedEventBrowseSchema)
+def browse_events(
+    request,
+    state: Literal["all", "completed", "upcoming", "open"] = "all",
+    event_type: Optional[str] = None,
+    search: Optional[str] = None,
+    date_from: Optional[str] = None,
+    date_to: Optional[str] = None,
+    price_min: Optional[int] = None,
+    price_max: Optional[int] = None,
+    free_only: bool = False,
+    page: int = 1,
+):
+    """Browse public events; price bounds and ceiling are in tomans, stored event prices are rials."""
+    page_size = 12
+    if page < 1:
+        raise HttpError(400, "شماره صفحه باید بزرگ‌تر از صفر باشد.")
+    if event_type and event_type not in Event.TypeChoices.values:
+        raise HttpError(400, "نوع رویداد معتبر نیست.")
+    if price_min is not None and price_min < 0:
+        raise HttpError(400, "حداقل قیمت نمی‌تواند منفی باشد.")
+    if price_max is not None and price_max < 0:
+        raise HttpError(400, "حداکثر قیمت نمی‌تواند منفی باشد.")
+    if price_min is not None and price_max is not None and price_min > price_max:
+        raise HttpError(400, "حداقل قیمت نمی‌تواند از حداکثر قیمت بیشتر باشد.")
+
+    selected_from = _parse_browse_date(date_from, "date_from")
+    selected_to = _parse_browse_date(date_to, "date_to")
+    if selected_from and selected_to and selected_from > selected_to:
+        raise HttpError(400, "تاریخ شروع نمی‌تواند بعد از تاریخ پایان باشد.")
+
+    public_statuses = [Event.StatusChoices.PUBLISHED, Event.StatusChoices.COMPLETED]
+    public_events = Event.objects.filter(is_deleted=False, status__in=public_statuses)
+    highest_price_rial = public_events.aggregate(value=Max("price"))["value"] or 0
+    price_ceiling = ceil(highest_price_rial / 10 / 1_000_000) * 1_000_000
+
+    now = timezone.now()
+    queryset = (
+        public_events
+        .annotate(
+            browse_registration_count=Count(
+                "registrations",
+                filter=Q(
+                    registrations__is_deleted=False,
+                ) & (
+                    Q(registrations__status__in=[
+                        Registration.StatusChoices.CONFIRMED,
+                        Registration.StatusChoices.ATTENDED,
+                    ])
+                    | Q(
+                        registrations__status=Registration.StatusChoices.PENDING,
+                        registrations__checkout_expires_at__gt=now,
+                    )
+                ),
+                distinct=True,
+            )
+        )
+        .prefetch_related("gallery_images")
+    )
+
+    if state == "completed":
+        queryset = queryset.filter(
+            Q(status=Event.StatusChoices.COMPLETED) | Q(end_time__lte=now)
+        )
+    elif state == "upcoming":
+        queryset = queryset.filter(
+            status=Event.StatusChoices.PUBLISHED,
+            start_time__gt=now,
+        ).exclude(_event_registration_open_query(now))
+    elif state == "open":
+        queryset = queryset.filter(_event_registration_open_query(now))
+
+    if event_type:
+        queryset = queryset.filter(event_type=event_type)
+    if search and search.strip():
+        queryset = queryset.filter(
+            Q(title__icontains=search.strip()) | Q(description__icontains=search.strip())
+        )
+    if selected_from:
+        queryset = queryset.filter(start_time__gte=selected_from)
+    if selected_to:
+        queryset = queryset.filter(start_time__lt=selected_to + timedelta(days=1))
+    if free_only:
+        queryset = queryset.filter(Q(price__isnull=True) | Q(price__lte=0))
+    else:
+        if price_min is not None:
+            queryset = queryset.filter(price__gte=price_min * 10)
+        if price_max is not None:
+            queryset = queryset.filter(price__lte=price_max * 10)
+
+    queryset = queryset.annotate(
+        published_first=Case(
+            When(status=Event.StatusChoices.PUBLISHED, then=0),
+            default=1,
+            output_field=IntegerField(),
+        )
+    ).order_by("published_first", "-start_time", "-id")
+
+    count = queryset.count()
+    total_pages = ceil(count / page_size) if count else 0
+    current_page = min(page, total_pages) if total_pages else 1
+    results = queryset[(current_page - 1) * page_size:current_page * page_size]
+
+    return {
+        "count": count,
+        "page": current_page,
+        "page_size": page_size,
+        "total_pages": total_pages,
+        "price_ceiling": price_ceiling,
+        "results": results,
+    }
+
 @events_router.get("/{int:event_id}", response=EventSchema)
 def get_event(request, event_id: int):
     """Get event details by ID"""
@@ -224,6 +374,7 @@ def update_event(request, event_id: int, payload: EventUpdateSchema):
     )
 
     if cancelled_now:
+        cancel_event_checkouts(event.id)
         _notify_event_update(
             event,
             notification_type="event_cancelled",
@@ -244,6 +395,45 @@ def update_event(request, event_id: int, payload: EventUpdateSchema):
 
     return 200, event
 
+
+@events_router.post("/{int:event_id}/checkout/cancel", response=MessageSchema, auth=jwt_auth)
+def cancel_registration_checkout(request, event_id: int):
+    """Cancel the user's active paid checkout and release its seat."""
+    with transaction.atomic():
+        event = get_object_or_404(
+            Event.objects.select_for_update(),
+            id=event_id,
+            is_deleted=False,
+        )
+        registration = (
+            Registration.objects.select_for_update()
+            .filter(
+                event=event,
+                user=request.auth,
+                status=Registration.StatusChoices.PENDING,
+                checkout_expires_at__isnull=False,
+                is_deleted=False,
+            )
+            .order_by("-registered_at", "-id")
+            .first()
+        )
+        if registration is None:
+            raise HttpError(409, "ثبت‌نام فعالی برای لغو وجود ندارد.")
+
+        payment = Payment.objects.select_for_update().filter(
+            registration=registration,
+        ).order_by("-created_at", "-id").first()
+        if payment and payment.status == Payment.OrderStatusChoices.PAID:
+            raise HttpError(409, "پرداخت تأیید شده است و امکان لغو پرداخت وجود ندارد.")
+
+        mark_checkout_cancelled(
+            registration,
+            Registration.CancellationReasonChoices.USER_CANCELLED,
+        )
+        queue_checkout_reconciliation(registration)
+
+    return {"message": "درخواست پرداخت لغو شد و ظرفیت آزاد شد."}
+
 @events_router.delete("/{int:event_id}", response={200: MessageSchema, 403: ErrorSchema}, auth=jwt_auth)
 def delete_event(request, event_id: int):
     """Soft delete an event"""
@@ -407,79 +597,109 @@ def register_for_event(
     payload: RegistrationCreateSchema | None = None,
 ):
     """Register current user for an event"""
-    event = get_object_or_404(Event, id=event_id, is_deleted=False)
     user = request.auth
+    now = timezone.now()
+    expire_stale_registration_checkouts(now=now, event_id=event_id)
 
-    if Registration.objects.filter(event=event, user=user, status=Registration.StatusChoices.CONFIRMED).exists():
+    with transaction.atomic():
-        raise HttpError(400, "شما قبلا در این ایونت ثبت‌نام کرده‌اید.")
+        event = get_object_or_404(
+            Event.objects.select_for_update(),
+            id=event_id,
+            is_deleted=False,
+        )
+        if Registration.objects.filter(
+            event=event,
+            user=user,
+            status__in=[Registration.StatusChoices.CONFIRMED, Registration.StatusChoices.ATTENDED],
+            is_deleted=False,
+        ).exists():
+            raise HttpError(400, "شما قبلا در این ایونت ثبت‌نام کرده‌اید.")
 
-    if event.registration_end_date and event.registration_end_date < timezone.now():
+        registration = (
-        raise HttpError(400, "مهلت ثبت‌نام به پایان رسیده‌است")
+            Registration.objects.select_for_update()
-    
+            .filter(event=event, user=user, is_deleted=False)
-    if event.registration_start_date and event.registration_start_date > timezone.now():
+            .order_by("-registered_at", "-id")
-        raise HttpError(400, "زمان ثبت‌نام هنوز آغاز نشده است")
+            .first()
+        )
+        if registration and registration.status == Registration.StatusChoices.PENDING:
+            if registration.checkout_expires_at is None:
+                # Preserve pre-timeout rows without backfilling or expiring them.
+                if registration.final_price is None:
+                    registration.final_price = event.price
+                    registration.save(update_fields=["final_price"])
+                return registration
+            if registration.checkout_expires_at > now:
+                # Existing checkouts may finish through their original window,
+                # even if registration has since closed or its held seat is full.
+                return registration
+            mark_checkout_cancelled(
+                registration,
+                Registration.CancellationReasonChoices.CHECKOUT_EXPIRED,
+            )
 
-    if not event.has_available_slots:
+        unresolved_attempt = Payment.objects.filter(
-        raise HttpError(400, "ظرفیت شرکت‌کنندگان تکمیل است")
+            user=user,
+            event=event,
+            registration__cancellation_reason__in=[
+                Registration.CancellationReasonChoices.CHECKOUT_EXPIRED,
+                Registration.CancellationReasonChoices.USER_CANCELLED,
+                Registration.CancellationReasonChoices.EVENT_CANCELLED,
+            ],
+        ).filter(
+            Q(status__in=[Payment.OrderStatusChoices.INIT, Payment.OrderStatusChoices.PENDING])
+            | Q(
+                status=Payment.OrderStatusChoices.PAID,
+                refund_status__in=[
+                    Payment.RefundStatusChoices.PENDING,
+                    Payment.RefundStatusChoices.MANUAL_REVIEW,
+                ],
+            )
+        ).exists()
+        if unresolved_attempt:
+            raise HttpError(409, "وضعیت پرداخت قبلی هنوز مشخص نشده است. پس از بررسی دوباره تلاش کنید.")
 
-    # Create or get existing registration
+        if event.status != Event.StatusChoices.PUBLISHED:
-    discount_code = None
+            raise HttpError(400, "ثبت‌نام این رویداد فعال نیست.")
-    if payload and payload.discount_code:
+        if event.registration_end_date and event.registration_end_date < now:
-        discount_code = payload.discount_code
+            raise HttpError(400, "مهلت ثبت‌نام به پایان رسیده‌است")
-    elif request.GET.get("discount_code"):
+        if event.registration_start_date and event.registration_start_date > now:
-        discount_code = request.GET.get("discount_code")
+            raise HttpError(400, "زمان ثبت‌نام هنوز آغاز نشده است")
+        if not event.has_available_slots:
+            raise HttpError(400, "ظرفیت شرکت‌کنندگان تکمیل است")
 
-    registration, created = Registration.objects.get_or_create(
+        discount_code_value = (
-        event=event,
+            payload.discount_code if payload and payload.discount_code
-        user=user,
+            else request.GET.get("discount_code")
-        status=Registration.StatusChoices.PENDING,
+        )
-        defaults={"final_price": event.price},
+        applied_code = None
-    )
+        discount_amount = 0
+        final_price = event.price or 0
+        if discount_code_value:
+            applied_code = DiscountCode.objects.filter(
+                code=discount_code_value,
+                applicable_events=event,
+                is_active=True,
+            ).first()
+            if not applied_code:
+                raise HttpError(400, "کد تخفیف برای این رویداد معتبر نیست.")
+            final_price, discount_amount = applied_code.calculate_discount(event, user)
 
-    if registration.status == Registration.StatusChoices.CONFIRMED:
+        is_free = final_price == 0
-        return HttpError(400, "شما قبلا در این ایونت ثبت‌نام کرده‌اید")
-
-    if registration.status == Registration.StatusChoices.CANCELLED:
         registration = Registration.objects.create(
             event=event,
             user=user,
-            status=Registration.StatusChoices.PENDING,
+            status=(
-            final_price=event.price,
+                Registration.StatusChoices.CONFIRMED
+                if is_free
+                else Registration.StatusChoices.PENDING
+            ),
+            checkout_started_at=None if is_free else now,
+            checkout_expires_at=None if is_free else now + CHECKOUT_TIMEOUT,
+            discount_code=applied_code,
+            discount_amount=discount_amount,
+            final_price=final_price,
         )
-    elif not created and registration.final_price is None:
+        return registration
-        registration.final_price = event.price
-        registration.save(update_fields=["final_price"])
-
-    applied_code = None
-    discount_amount = 0
-    final_price = event.price
-    fields_to_update = []
-
-    if discount_code:
-        applied_code = DiscountCode.objects.filter(
-            code=discount_code,
-            applicable_events=event,
-            is_active=True,
-        ).first()
-        if not applied_code:
-            raise HttpError(400, "UcO_ O<>OrU?UOU? U.O1O<31>O\"O<EFBFBD> U+UOO3O<33>")
-        final_price, discount_amount = applied_code.calculate_discount(event, user)
-        registration.discount_code = applied_code
-        registration.discount_amount = discount_amount
-        fields_to_update.extend(["discount_code", "discount_amount"])
-
-    if registration.final_price != final_price:
-        registration.final_price = final_price
-        fields_to_update.append("final_price")
-
-    if not event.price or final_price == 0:
-        registration.status = Registration.StatusChoices.CONFIRMED
-        fields_to_update.append("status")
-
-    if fields_to_update:
-        registration.save(update_fields=list(set(fields_to_update)))
-
-    return registration
 
 @events_router.put("/registrations/{int:registration_id}", response=RegistrationSchema, auth=jwt_auth)
 def update_registration_status(request, registration_id: int, payload: RegistrationStatusUpdateSchema):
@@ -488,11 +708,36 @@ def update_registration_status(request, registration_id: int, payload: Registrat
 
     registration = get_object_or_404(Registration, id=registration_id, user=user, is_deleted=False)
     requested_status = payload.dict(exclude_unset=True).get('status')
-    if requested_status == Registration.StatusChoices.ATTENDED:
+    if requested_status != Registration.StatusChoices.CANCELLED:
-        raise HttpError(403, "حضور رویداد فقط توسط برگزارکننده تأیید می‌شود.")
+        raise HttpError(403, "وضعیت ثبت‌نام فقط پس از تأیید پرداخت توسط سامانه تغییر می‌کند.")
-    registration.status = requested_status
+    with transaction.atomic():
-    registration.full_clean()
+        Event.objects.select_for_update().get(pk=registration.event_id)
-    registration.save()
+        registration = Registration.objects.select_for_update().get(pk=registration.pk)
+        payment = Payment.objects.select_for_update().filter(
+            registration=registration,
+        ).order_by("-created_at", "-id").first()
+        if payment and payment.status == Payment.OrderStatusChoices.PAID:
+            raise HttpError(409, "پرداخت تأیید شده است؛ امکان لغو این ثبت‌نام وجود ندارد.")
+        if payment and payment.status in (
+            Payment.OrderStatusChoices.INIT,
+            Payment.OrderStatusChoices.PENDING,
+        ) and not registration.checkout_expires_at:
+            raise HttpError(409, "تراکنش ثبت‌نام در حال بررسی است؛ برای لغو با پشتیبانی تماس بگیرید.")
+        if registration.status == Registration.StatusChoices.PENDING and registration.checkout_expires_at:
+            mark_checkout_cancelled(
+                registration,
+                Registration.CancellationReasonChoices.USER_CANCELLED,
+            )
+            queue_checkout_reconciliation(registration)
+        elif payment and payment.status in (
+            Payment.OrderStatusChoices.INIT,
+            Payment.OrderStatusChoices.PENDING,
+        ):
+            raise HttpError(409, "تراکنش ثبت‌نام در حال بررسی است؛ برای لغو با پشتیبانی تماس بگیرید.")
+        else:
+            registration.status = requested_status
+            registration.full_clean()
+            registration.save()
 
     return registration
 
@@ -501,8 +746,33 @@ def cancel_registration(request, registration_id: int):
     """Cancel a registration"""
     user = request.auth
 
-    registration = get_object_or_404(Registration, id=registration_id, user=user, is_deleted=False)
+    registration = get_object_or_404(
-    registration.delete()
+        Registration,
+        id=registration_id,
+        user=user,
+        is_deleted=False,
+    )
+    with transaction.atomic():
+        Event.objects.select_for_update().get(pk=registration.event_id)
+        registration = Registration.objects.select_for_update().get(pk=registration.pk)
+        payment = Payment.objects.select_for_update().filter(
+            registration=registration,
+        ).order_by("-created_at", "-id").first()
+        if payment and payment.status == Payment.OrderStatusChoices.PAID:
+            raise HttpError(409, "پرداخت این ثبت‌نام تأیید شده است؛ برای پیگیری با پشتیبانی تماس بگیرید.")
+        if registration.status == Registration.StatusChoices.PENDING and registration.checkout_expires_at:
+            mark_checkout_cancelled(
+                registration,
+                Registration.CancellationReasonChoices.USER_CANCELLED,
+            )
+            queue_checkout_reconciliation(registration)
+        elif payment and payment.status in (
+            Payment.OrderStatusChoices.INIT,
+            Payment.OrderStatusChoices.PENDING,
+        ):
+            raise HttpError(409, "تراکنش ثبت‌نام در حال بررسی است؛ برای لغو با پشتیبانی تماس بگیرید.")
+        else:
+            registration.delete()
     return {"message": "ثبت‌نام شما لغو شد :("}
 
 @events_router.get("/registerations/verify/{UUID:ticket_id}", response=RegisterationDetailSchema, auth=jwt_auth)
@@ -523,6 +793,53 @@ def verify_my_registration(request, ticket_id: UUID):
 
 
 
+def _my_registration_checkout_fields(registration, now):
+    payment = registration.payments.order_by("-created_at", "-id").first()
+    checkout_state = "none"
+    can_resume = False
+    if registration.status == Registration.StatusChoices.PENDING:
+        if payment and payment.status == Payment.OrderStatusChoices.PAID:
+            checkout_state = "unresolved"
+        elif registration.checkout_expires_at is None:
+            checkout_state = "legacy_pending"
+        elif registration.checkout_expires_at > now:
+            checkout_state = "active"
+            can_resume = not bool(payment and payment.verification_manual_review_at)
+        else:
+            checkout_state = "expired"
+    elif registration.status == Registration.StatusChoices.CANCELLED:
+        checkout_state = "cancelled"
+        if payment and (
+            payment.status in (Payment.OrderStatusChoices.INIT, Payment.OrderStatusChoices.PENDING)
+            or (
+                payment.status == Payment.OrderStatusChoices.PAID
+                and payment.refund_status in (
+                    Payment.RefundStatusChoices.PENDING,
+                    Payment.RefundStatusChoices.MANUAL_REVIEW,
+                )
+            )
+        ):
+            checkout_state = "unresolved"
+
+    payment_status = None
+    if payment:
+        payment_status = {
+            Payment.OrderStatusChoices.INIT: "initiated",
+            Payment.OrderStatusChoices.PENDING: "pending",
+            Payment.OrderStatusChoices.PAID: "paid",
+            Payment.OrderStatusChoices.FAILED: "failed",
+            Payment.OrderStatusChoices.CANCELED: "canceled",
+        }[payment.status]
+    return {
+        "checkout_state": checkout_state,
+        "checkout_expires_at": registration.checkout_expires_at,
+        "payment_id": payment.id if payment else None,
+        "payment_status": payment_status,
+        "refund_status": payment.refund_status if payment else None,
+        "can_resume": can_resume,
+    }
+
+
 @events_router.get("/my-registrations/paginated", response=PaginatedMyEventRegistrationsSchema, auth=jwt_auth)
 def my_registrations_paginated(
     request,
@@ -542,11 +859,14 @@ def my_registrations_paginated(
     count = queryset.count()
     total_pages = max(1, (count + page_size - 1) // page_size)
     start = (page - 1) * page_size
+    now = timezone.now()
     results = [
         MyEventRegistrationOut(
             id=registration.id,
+            ticket_id=registration.ticket_id,
             created_at=registration.created_at,
             status=registration.status,
+            **_my_registration_checkout_fields(registration, now),
             event=EventBriefSchema(
                 id=registration.event.id,
                 title=registration.event.title,
@@ -582,12 +902,15 @@ def my_registrations(request):
         .order_by("-created_at")
     )
     out: List[MyEventRegistrationOut] = []
+    now = timezone.now()
     for r in qs:
         out.append(
             MyEventRegistrationOut(
                 id=r.id,
+                ticket_id=r.ticket_id,
                 created_at=r.created_at,
                 status=r.status,
+                **_my_registration_checkout_fields(r, now),
                 event=EventBriefSchema(
                     id=r.event.id,
                     title=r.event.title,
@@ -604,12 +927,337 @@ def my_registrations(request):
 
 @events_router.get("/{event_id}/is-registered", response=RegistrationStatusOut, auth=jwt_auth)
 def is_registered(request, event_id: int):
-    exists = Registration.objects.filter(
+    now = timezone.now()
-        user=request.auth,
+    registration = (
-        event_id=event_id,
+        Registration.objects.filter(
-        status=Registration.StatusChoices.CONFIRMED
+            user=request.auth,
-    ).exists()
+            event_id=event_id,
-    return {"is_registered": exists}
+            is_deleted=False,
+        )
+        .order_by("-registered_at", "-id")
+        .first()
+    )
+    if registration and registration.status == Registration.StatusChoices.PENDING and registration.checkout_expires_at and registration.checkout_expires_at <= now:
+        expire_stale_registration_checkouts(now=now, event_id=event_id)
+        registration.refresh_from_db()
+
+    payment = None
+    if registration:
+        payment = registration.payments.order_by("-created_at", "-id").first()
+
+    is_confirmed = bool(
+        registration
+        and registration.status in [Registration.StatusChoices.CONFIRMED, Registration.StatusChoices.ATTENDED]
+    )
+    checkout_state = "none"
+    can_resume = False
+    can_cancel = False
+    if is_confirmed:
+        checkout_state = "confirmed"
+    elif registration and registration.status == Registration.StatusChoices.PENDING:
+        if payment and payment.status == Payment.OrderStatusChoices.PAID:
+            checkout_state = "unresolved"
+        elif registration.checkout_expires_at is None:
+            checkout_state = "legacy_pending"
+        elif registration.checkout_expires_at > now:
+            checkout_state = "active"
+            can_resume = not bool(payment and payment.verification_manual_review_at)
+            can_cancel = True
+        else:
+            checkout_state = "expired"
+    elif registration and registration.status == Registration.StatusChoices.CANCELLED:
+        checkout_state = "cancelled"
+        if payment and (
+            payment.status in [Payment.OrderStatusChoices.INIT, Payment.OrderStatusChoices.PENDING]
+            or (
+                payment.status == Payment.OrderStatusChoices.PAID
+                and payment.refund_status in [
+                    Payment.RefundStatusChoices.PENDING,
+                    Payment.RefundStatusChoices.MANUAL_REVIEW,
+                ]
+            )
+        ):
+            checkout_state = "unresolved"
+
+    payment_status = None
+    if payment:
+        payment_status = {
+            Payment.OrderStatusChoices.INIT: "initiated",
+            Payment.OrderStatusChoices.PENDING: "pending",
+            Payment.OrderStatusChoices.PAID: "paid",
+            Payment.OrderStatusChoices.FAILED: "failed",
+            Payment.OrderStatusChoices.CANCELED: "canceled",
+        }[payment.status]
+
+    return {
+        "is_registered": is_confirmed,
+        "checkout_state": checkout_state,
+        "registration_id": registration.id if registration else None,
+        "registration_status": registration.status if registration else None,
+        "ticket_id": str(registration.ticket_id) if registration else None,
+        "checkout_expires_at": registration.checkout_expires_at if registration else None,
+        "payment_id": payment.id if payment else None,
+        "payment_status": payment_status,
+        "refund_status": payment.refund_status if payment else None,
+        "can_resume": can_resume,
+        "can_cancel": can_cancel,
+    }
+
+
+def _registration_hub_state(registration, payment, now):
+    if payment:
+        if payment.refund_status == Payment.RefundStatusChoices.PENDING:
+            return "refund_pending"
+        if payment.refund_status == Payment.RefundStatusChoices.MANUAL_REVIEW:
+            return "refund_manual_review"
+        if payment.refund_status == Payment.RefundStatusChoices.SUCCEEDED:
+            return "refund_succeeded"
+
+        if payment.status == Payment.OrderStatusChoices.FAILED:
+            return "failed"
+        if payment.status == Payment.OrderStatusChoices.CANCELED:
+            return "cancelled"
+        if payment.verification_manual_review_at:
+            return "manual_review"
+
+        if payment.status == Payment.OrderStatusChoices.PAID:
+            if registration and registration.status in (
+                Registration.StatusChoices.CONFIRMED,
+                Registration.StatusChoices.ATTENDED,
+            ):
+                return "paid_success"
+            # A charge without a confirmed registration must not be presented as
+            # a successful registration. Keep the saved transaction visible for review.
+            return "manual_review"
+
+        if payment.status in (
+            Payment.OrderStatusChoices.INIT,
+            Payment.OrderStatusChoices.PENDING,
+        ):
+            if registration and registration.status == Registration.StatusChoices.PENDING:
+                if registration.checkout_expires_at is None:
+                    return "legacy_pending"
+                if registration.checkout_expires_at > now:
+                    return "active_checkout"
+            return "verification_pending"
+
+    if registration:
+        if registration.status in (
+            Registration.StatusChoices.CONFIRMED,
+            Registration.StatusChoices.ATTENDED,
+        ):
+            return "free_success" if (registration.final_price or 0) <= 0 else "manual_review"
+        if registration.status == Registration.StatusChoices.PENDING:
+            if registration.checkout_expires_at is None:
+                return "legacy_pending"
+            if registration.checkout_expires_at > now:
+                return "active_checkout"
+            return "expired"
+        if registration.status == Registration.StatusChoices.CANCELLED:
+            if registration.cancellation_reason == Registration.CancellationReasonChoices.CHECKOUT_EXPIRED:
+                return "expired"
+            if registration.cancellation_reason == Registration.CancellationReasonChoices.PAYMENT_FAILED:
+                return "failed"
+            return "cancelled"
+
+    return "ready"
+
+
+def _registration_hub_records(event, user, registration_id, payment_id, now):
+    if registration_id:
+        registration = Registration.objects.filter(
+            ticket_id=registration_id,
+            event=event,
+            user=user,
+            is_deleted=False,
+        ).first()
+        if registration is None:
+            return None, None
+        payment = registration.payments.order_by("-created_at", "-id").first()
+        return registration, payment
+
+    if payment_id:
+        payment = Payment.objects.select_related("registration").filter(
+            pk=payment_id,
+            event=event,
+            user=user,
+        ).first()
+        if payment is None:
+            return None, None
+        registration = payment.registration
+        if registration is not None and (
+            registration.event_id != event.id or registration.user_id != user.id
+        ):
+            registration = None
+        return registration, payment
+
+    registrations = list(
+        Registration.objects.filter(event=event, user=user, is_deleted=False)
+        .prefetch_related("payments")
+        .order_by("-registered_at", "-id")
+    )
+    registration_payments = {
+        registration.id: registration.payments.order_by("-created_at", "-id").first()
+        for registration in registrations
+    }
+    payments = list(
+        Payment.objects.filter(event=event, user=user)
+        .select_related("registration")
+        .order_by("-created_at", "-id")
+    )
+
+    unresolved = []
+    for registration in registrations:
+        payment = registration_payments[registration.id]
+        state = _registration_hub_state(registration, payment, now)
+        if state in {
+            "active_checkout", "legacy_pending", "verification_pending", "manual_review",
+            "refund_pending", "refund_manual_review",
+        }:
+            unresolved.append((registration.registered_at, registration, payment))
+
+    linked_registration_ids = set(registration_payments)
+    for payment in payments:
+        if payment.registration_id in linked_registration_ids:
+            continue
+        state = _registration_hub_state(payment.registration, payment, now)
+        if state in {
+            "active_checkout", "legacy_pending", "verification_pending", "manual_review",
+            "refund_pending", "refund_manual_review",
+        }:
+            unresolved.append((payment.created_at, payment.registration, payment))
+
+    if unresolved:
+        _, registration, payment = max(unresolved, key=lambda item: item[0])
+        return registration, payment
+    if registrations:
+        registration = registrations[0]
+        return registration, registration_payments[registration.id]
+    if payments:
+        return payments[0].registration, payments[0]
+    return None, None
+
+
+@events_router.get("/{str:slug}/registration/status", response=RegistrationHubOut, auth=jwt_auth)
+def registration_hub_status(
+    request,
+    slug: str,
+    registration_id: Optional[UUID] = None,
+    payment_id: Optional[int] = None,
+):
+    """Return the authenticated user's authoritative registration/payment view for an event."""
+    if registration_id and payment_id:
+        raise HttpError(400, "فقط یکی از شناسه‌های ثبت‌نام یا پرداخت را ارسال کنید.")
+
+    event = Event.objects.filter(slug=slug, is_deleted=False).first()
+    if event is None:
+        lookup = {"pk": int(slug)} if slug.isdecimal() else {"slug": slug}
+        event = get_object_or_404(Event, is_deleted=False, **lookup)
+    now = timezone.now()
+    expire_stale_registration_checkouts(now=now, event_id=event.id)
+    registration, payment = _registration_hub_records(
+        event,
+        request.auth,
+        registration_id,
+        payment_id,
+        now,
+    )
+    if (registration_id or payment_id) and registration is None and payment is None:
+        raise HttpError(404, "وضعیت ثبت‌نام یا پرداخت پیدا نشد.")
+
+    state = _registration_hub_state(registration, payment, now)
+    unresolved = state in {
+        "active_checkout", "legacy_pending", "verification_pending", "manual_review",
+        "refund_pending", "refund_manual_review",
+    }
+    can_resume = bool(
+        state == "active_checkout"
+        and registration
+        and registration.status == Registration.StatusChoices.PENDING
+        and (payment is None or not payment.verification_manual_review_at)
+    )
+    can_cancel = bool(
+        state == "active_checkout"
+        and registration
+        and registration.status == Registration.StatusChoices.PENDING
+        and registration.checkout_expires_at
+        and registration.checkout_expires_at > now
+    )
+    registration_is_settled = bool(
+        registration
+        and registration.status in (
+            Registration.StatusChoices.CONFIRMED,
+            Registration.StatusChoices.ATTENDED,
+        )
+    )
+    registration_window_open = bool(
+        event.status == Event.StatusChoices.PUBLISHED
+        and event.is_registration_open
+        and event.has_available_slots
+    )
+    can_register = bool(registration_window_open and not unresolved and not registration_is_settled)
+
+    image_url = None
+    if event.featured_image and hasattr(event.featured_image, "url"):
+        image_url = request.build_absolute_uri(event.featured_image.url)
+
+    payment_status = None
+    if payment:
+        payment_status = {
+            Payment.OrderStatusChoices.INIT: "initiated",
+            Payment.OrderStatusChoices.PENDING: "pending",
+            Payment.OrderStatusChoices.PAID: "paid",
+            Payment.OrderStatusChoices.FAILED: "failed",
+            Payment.OrderStatusChoices.CANCELED: "canceled",
+        }[payment.status]
+
+    return {
+        "state": state,
+        "event": {
+            "id": event.id,
+            "title": event.title,
+            "slug": event.slug,
+            "description": event.description,
+            "event_type": event.event_type,
+            "address": event.address,
+            "location": event.location,
+            "start_time": event.start_time,
+            "end_time": event.end_time,
+            "registration_start_date": event.registration_start_date,
+            "registration_end_date": event.registration_end_date,
+            "capacity": event.capacity,
+            "price": event.price,
+            "status": event.status,
+            "registration_count": event.current_attendees_count,
+            "image_url": image_url,
+            "registration_success_markdown": event.registration_success_markdown,
+        },
+        "registration": {
+            "ticket_id": registration.ticket_id,
+            "status": registration.status,
+            "registered_at": registration.registered_at,
+            "checkout_started_at": registration.checkout_started_at,
+            "checkout_expires_at": registration.checkout_expires_at,
+            "cancellation_reason": registration.cancellation_reason,
+            "final_price": registration.final_price,
+            "discount_amount": registration.discount_amount,
+        } if registration else None,
+        "payment": {
+            "id": payment.id,
+            "status": payment_status,
+            "verification_state": payment.verification_state,
+            "refund_status": payment.refund_status,
+            "base_amount": payment.base_amount,
+            "discount_amount": payment.discount_amount,
+            "amount": payment.amount,
+            "ref_id": payment.ref_id,
+            "created_at": payment.created_at,
+            "gateway_paid_at": payment.gateway_paid_at,
+        } if payment else None,
+        "can_register": can_register,
+        "can_resume": can_resume,
+        "can_cancel": can_cancel,
+    }
 @events_router.get("/{int:event_id}/admin-detail", response=EventAdminDetailSchema, auth=jwt_auth)
 def event_admin_detail(request, event_id: int):
     user = request.auth

apps/events/checkout.py

@@ -0,0 +1,136 @@
+"""Registration checkout lifecycle rules shared by API views and workers."""
+
+import logging
+from datetime import timedelta
+
+from django.db import transaction
+from django.utils import timezone
+
+from apps.events.models import Event, Registration
+
+
+CHECKOUT_TIMEOUT = timedelta(minutes=15)
+logger = logging.getLogger(__name__)
+
+
+def _dispatch_reconciliation(payment_id):
+    from apps.payments.tasks import reconcile_payment
+
+    try:
+        reconcile_payment.apply_async(args=(payment_id,), countdown=0)
+    except Exception:
+        logger.exception("Unable to dispatch checkout payment %s for reconciliation", payment_id)
+
+
+def mark_checkout_cancelled(registration, reason):
+    """Cancel a pending checkout without deleting its historical registration."""
+    if registration.status != Registration.StatusChoices.PENDING:
+        return False
+
+    registration.status = Registration.StatusChoices.CANCELLED
+    registration.cancellation_reason = reason
+    registration.save(update_fields=[
+        "status",
+        "cancellation_reason",
+        "updated_at",
+    ])
+    return True
+
+
+def queue_checkout_reconciliation(registration):
+    """Reconcile each unresolved payment after a checkout is cancelled."""
+    from apps.payments.models import Payment
+
+    payments = list(
+        Payment.objects.filter(
+            registration=registration,
+            status__in=[
+                Payment.OrderStatusChoices.INIT,
+                Payment.OrderStatusChoices.PENDING,
+            ],
+        ).only("id", "authority")
+    )
+    for payment in payments:
+        if payment.authority:
+            transaction.on_commit(
+                lambda payment_id=payment.id: _dispatch_reconciliation(payment_id)
+            )
+        else:
+            # The payment request may have reached the gateway before its
+            # authority was persisted. Keep it visible for review until its
+            # request response arrives or an administrator resolves it.
+            Payment.objects.filter(
+                pk=payment.id,
+                status__in=[
+                    Payment.OrderStatusChoices.INIT,
+                    Payment.OrderStatusChoices.PENDING,
+                ],
+                authority__isnull=True,
+            ).update(verification_manual_review_at=timezone.now())
+
+
+@transaction.atomic
+def expire_stale_registration_checkouts(*, now=None, event_id=None):
+    """Release seats for new-format pending checkouts whose deadline passed.
+
+    Legacy registrations have a null checkout deadline and are intentionally
+    excluded from this timeout sweep.
+    """
+    now = now or timezone.now()
+    candidates = Registration.objects.filter(
+        status=Registration.StatusChoices.PENDING,
+        is_deleted=False,
+        checkout_expires_at__lte=now,
+    )
+    if event_id is not None:
+        candidates = candidates.filter(event_id=event_id)
+
+    expired_count = 0
+    for registration_id in candidates.values_list("id", flat=True).iterator():
+        registration = (
+            Registration.objects.select_for_update()
+            .filter(pk=registration_id)
+            .first()
+        )
+        if registration is None or registration.status != Registration.StatusChoices.PENDING:
+            continue
+
+        reason = (
+            Registration.CancellationReasonChoices.EVENT_CANCELLED
+            if registration.event.status == Event.StatusChoices.CANCELLED
+            else Registration.CancellationReasonChoices.CHECKOUT_EXPIRED
+        )
+        if mark_checkout_cancelled(registration, reason):
+            expired_count += 1
+            queue_checkout_reconciliation(registration)
+
+    return expired_count
+
+
+@transaction.atomic
+def cancel_event_checkouts(event_id):
+    """Cancel active new-format checkouts when an organizer cancels an event."""
+    event = Event.objects.select_for_update().filter(pk=event_id).first()
+    if event is None:
+        return 0
+
+    now = timezone.now()
+    registrations = (
+        Registration.objects.select_for_update()
+        .filter(
+            event=event,
+            is_deleted=False,
+            status=Registration.StatusChoices.PENDING,
+            checkout_expires_at__isnull=False,
+        )
+        .order_by("pk")
+    )
+    cancelled_count = 0
+    for registration in registrations:
+        if mark_checkout_cancelled(
+            registration,
+            Registration.CancellationReasonChoices.EVENT_CANCELLED,
+        ):
+            cancelled_count += 1
+            queue_checkout_reconciliation(registration)
+    return cancelled_count

apps/events/migrations/0016_registration_cancellation_reason_and_more.py

@@ -0,0 +1,28 @@
+# Generated by Django 5.2.5 on 2026-09-30 19:44
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('events', '0015_registration_attendance_verification_source_and_more'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='registration',
+            name='cancellation_reason',
+            field=models.CharField(blank=True, choices=[('checkout_expired', 'Checkout expired'), ('user_cancelled', 'User cancelled checkout'), ('event_cancelled', 'Event cancelled'), ('payment_failed', 'Payment failed')], default='', editable=False, max_length=32),
+        ),
+        migrations.AddField(
+            model_name='registration',
+            name='checkout_expires_at',
+            field=models.DateTimeField(blank=True, editable=False, null=True),
+        ),
+        migrations.AddField(
+            model_name='registration',
+            name='checkout_started_at',
+            field=models.DateTimeField(blank=True, editable=False, null=True),
+        ),
+    ]

apps/events/models.py

@@ -108,8 +108,15 @@ class Event(BaseModel):
 
     @property
     def current_attendees_count(self):
-        """Count confirmed attendees"""
+        """Count confirmed attendees and currently held paid-checkout seats."""
-        return self.registrations.filter(status__in=[Registration.StatusChoices.CONFIRMED, Registration.StatusChoices.ATTENDED], is_deleted=False).count()
+        now = timezone.now()
+        return self.registrations.filter(is_deleted=False).filter(
+            models.Q(status__in=[Registration.StatusChoices.CONFIRMED, Registration.StatusChoices.ATTENDED])
+            | models.Q(
+                status=Registration.StatusChoices.PENDING,
+                checkout_expires_at__gt=now,
+            )
+        ).count()
 
     @property
     def has_available_slots(self):
@@ -132,9 +139,24 @@ class Registration(BaseModel):
         SYSTEM = 'system', 'System'
         HISTORICAL = 'historical', 'Historical backfill'
 
+    class CancellationReasonChoices(models.TextChoices):
+        CHECKOUT_EXPIRED = 'checkout_expired', 'Checkout expired'
+        USER_CANCELLED = 'user_cancelled', 'User cancelled checkout'
+        EVENT_CANCELLED = 'event_cancelled', 'Event cancelled'
+        PAYMENT_FAILED = 'payment_failed', 'Payment failed'
+
     event = models.ForeignKey(Event, on_delete=models.CASCADE, related_name='registrations')
     user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name='event_registrations')
     registered_at = models.DateTimeField(auto_now_add=True)
+    checkout_started_at = models.DateTimeField(null=True, blank=True, editable=False)
+    checkout_expires_at = models.DateTimeField(null=True, blank=True, editable=False)
+    cancellation_reason = models.CharField(
+        max_length=32,
+        choices=CancellationReasonChoices.choices,
+        blank=True,
+        default='',
+        editable=False,
+    )
     status = models.CharField(max_length=10, choices=StatusChoices.choices,
                               default=StatusChoices.PENDING)
     attendance_verified_at = models.DateTimeField(null=True, blank=True)

apps/events/tasks.py

@@ -5,12 +5,19 @@ import logging
 from celery import shared_task
 
 from apps.events.models import Registration
+from apps.events.checkout import expire_stale_registration_checkouts
 from apps.notifications.services import notify_user
 from apps.users.tasks import send_critical_sms
 
 logger = logging.getLogger(__name__)
 
 
+@shared_task(name="apps.events.expire_stale_registration_checkouts")
+def expire_stale_registration_checkouts_task():
+    """Release seats held by new checkout attempts that reached their deadline."""
+    return expire_stale_registration_checkouts()
+
+
 @shared_task(bind=True, max_retries=3)
 def send_registration_confirmation_notification(self, registration_pk: str):
     try:

apps/events/tests/integration/test_events.py

@@ -3,7 +3,7 @@ import io
 import json
 import tempfile
 import uuid
-from datetime import timedelta
+from datetime import datetime, time as datetime_time, timedelta
 from types import SimpleNamespace
 from PIL import Image
 from django.core.files.uploadedfile import SimpleUploadedFile
@@ -110,6 +110,115 @@ class TestEventsAPIIntegrationTests:
         assert response.status_code == 200
         assert any((item['id'] == event.id for item in response.json()))
 
+    def test_browse_events_returns_numbered_pages_and_global_price_ceiling(self):
+        self._create_event(title='Price ceiling 650k toman', price=6500000)
+        self._create_event(title='Price ceiling 4.3m toman', price=43000000)
+        for index in range(13):
+            self._create_event(title=f'Browse page event {index}', price=100000)
+
+        first_page = self.client.get('/api/events/browse/', {'page': 1})
+        second_page = self.client.get('/api/events/browse/', {'page': 2})
+
+        assert first_page.status_code == 200
+        assert first_page.json()['count'] == 17
+        assert first_page.json()['page'] == 1
+        assert first_page.json()['page_size'] == 12
+        assert first_page.json()['total_pages'] == 2
+        assert len(first_page.json()['results']) == 12
+        assert second_page.json()['page'] == 2
+        assert len(second_page.json()['results']) == 5
+        assert first_page.json()['price_ceiling'] == 5000000
+        assert 'address' in first_page.json()['results'][0]
+
+    def test_browse_events_upcoming_includes_future_events_that_cannot_register(self):
+        now = timezone.now()
+        open_event = self._create_event(
+            title='Browse open event',
+            start_time=now + timedelta(days=4),
+            end_time=now + timedelta(days=4, hours=2),
+            registration_start_date=now - timedelta(days=1),
+            registration_end_date=now + timedelta(days=2),
+        )
+        not_started = self._create_event(
+            title='Browse not started event',
+            start_time=now + timedelta(days=5),
+            end_time=now + timedelta(days=5, hours=2),
+            registration_start_date=now + timedelta(days=1),
+        )
+        closed = self._create_event(
+            title='Browse closed event',
+            start_time=now + timedelta(days=6),
+            end_time=now + timedelta(days=6, hours=2),
+            registration_end_date=now - timedelta(minutes=1),
+        )
+        full = self._create_event(
+            title='Browse full event',
+            start_time=now + timedelta(days=7),
+            end_time=now + timedelta(days=7, hours=2),
+            capacity=1,
+        )
+        self._create_registration(full, self.user, status=Registration.StatusChoices.CONFIRMED)
+
+        upcoming = self.client.get('/api/events/browse/', {'state': 'upcoming', 'search': 'Browse'}).json()
+        open_results = self.client.get('/api/events/browse/', {'state': 'open', 'search': 'Browse'}).json()
+        upcoming_ids = {item['id'] for item in upcoming['results']}
+        open_ids = {item['id'] for item in open_results['results']}
+
+        assert {not_started.id, closed.id, full.id}.issubset(upcoming_ids)
+        assert open_event.id not in upcoming_ids
+        assert open_ids == {open_event.id}
+
+    def test_browse_events_filters_start_dates_inclusive_and_combines_type_price_and_free(self):
+        selected_day = timezone.localdate()
+        local_timezone = timezone.get_current_timezone()
+
+        def at(day, hour, minute):
+            return timezone.make_aware(datetime.combine(day, datetime_time(hour, minute)), local_timezone)
+
+        start_day = self._create_event(
+            title='Date range probe free',
+            event_type=Event.TypeChoices.ONLINE,
+            price=0,
+            start_time=at(selected_day, 0, 0),
+            end_time=at(selected_day, 2, 0),
+        )
+        end_day = self._create_event(
+            title='Date range probe paid online',
+            event_type=Event.TypeChoices.ONLINE,
+            price=300000,
+            start_time=at(selected_day, 23, 59),
+            end_time=at(selected_day + timedelta(days=1), 1, 0),
+        )
+        self._create_event(
+            title='Date range probe paid onsite',
+            event_type=Event.TypeChoices.ON_SITE,
+            price=300000,
+            start_time=at(selected_day, 12, 0),
+            end_time=at(selected_day, 14, 0),
+        )
+        outside_day = self._create_event(
+            title='Date range probe outside',
+            event_type=Event.TypeChoices.ONLINE,
+            price=300000,
+            start_time=at(selected_day + timedelta(days=1), 0, 0),
+            end_time=at(selected_day + timedelta(days=1), 2, 0),
+        )
+
+        params = {
+            'search': 'Date range probe',
+            'date_from': selected_day.isoformat(),
+            'date_to': selected_day.isoformat(),
+            'event_type': Event.TypeChoices.ONLINE,
+            'price_min': 10000,
+            'price_max': 40000,
+        }
+        paid_results = self.client.get('/api/events/browse/', params).json()
+        free_results = self.client.get('/api/events/browse/', {**params, 'free_only': 'true'}).json()
+
+        assert {item['id'] for item in paid_results['results']} == {end_day.id}
+        assert {item['id'] for item in free_results['results']} == {start_day.id}
+        assert outside_day.id not in {item['id'] for item in paid_results['results']}
+
     def test_list_events_handles_comma_status_parameter(self):
         event = self._create_event(title='Comma Event', status=Event.StatusChoices.PUBLISHED)
         results = list_events(None, status=f'{Event.StatusChoices.PUBLISHED},{Event.StatusChoices.DRAFT}', event_type=None, search=None, limit=10, offset=0)

apps/events/tests/integration/test_registration_checkout.py

@@ -0,0 +1,480 @@
+import json
+import uuid
+from datetime import timedelta
+
+import pytest
+from django.test import Client
+from django.utils import timezone
+
+from apps.events.models import Event, Registration
+from apps.events.checkout import cancel_event_checkouts, expire_stale_registration_checkouts
+from apps.payments.models import Payment
+from apps.users.models import User
+from core.authentication import create_jwt_token
+
+
+@pytest.mark.django_db
+@pytest.mark.integration
+class TestRegistrationCheckout:
+    def setup_method(self):
+        self.client = Client()
+        suffix = uuid.uuid4().hex[:10]
+        self.user = User.objects.create_user(
+            username=f"checkout-{suffix}",
+            email=f"checkout-{suffix}@example.com",
+            mobile=f"0912{suffix[:7]}",
+            password="CheckoutPass!123",
+        )
+        self.token = create_jwt_token(self.user)
+        now = timezone.now()
+        self.event = Event.objects.create(
+            title="Checkout event",
+            description="Paid checkout behavior test",
+            start_time=now + timedelta(days=2),
+            end_time=now + timedelta(days=2, hours=1),
+            registration_start_date=now - timedelta(days=1),
+            registration_end_date=now + timedelta(days=1),
+            slug=f"checkout-{suffix}",
+            price=1250000,
+            capacity=1,
+            status=Event.StatusChoices.PUBLISHED,
+        )
+
+    def auth_headers(self):
+        return {"HTTP_AUTHORIZATION": f"Bearer {self.token}"}
+
+    def create_pending_checkout(self, *, expires_at=None):
+        now = timezone.now()
+        registration = Registration.objects.create(
+            event=self.event,
+            user=self.user,
+            status=Registration.StatusChoices.PENDING,
+            final_price=self.event.price,
+            checkout_started_at=now,
+            checkout_expires_at=expires_at or now + timedelta(minutes=15),
+        )
+        payment = Payment.objects.create(
+            user=self.user,
+            event=self.event,
+            registration=registration,
+            base_amount=self.event.price,
+            amount=self.event.price,
+            status=Payment.OrderStatusChoices.PENDING,
+            authority=f"AUTH-{uuid.uuid4().hex}",
+            idempotency_key=uuid.uuid4(),
+        )
+        return registration, payment
+
+    def test_active_checkout_reserves_capacity_but_can_be_resumed_by_its_owner(self):
+        registration, _ = self.create_pending_checkout()
+
+        assert Event.objects.get(pk=self.event.pk).current_attendees_count == 1
+        resume_response = self.client.post(
+            f"/api/events/{self.event.id}/register",
+            data=json.dumps({}),
+            content_type="application/json",
+            **self.auth_headers(),
+        )
+
+        other = User.objects.create_user(
+            username=f"other-{uuid.uuid4().hex[:8]}",
+            email=f"other-{uuid.uuid4().hex[:8]}@example.com",
+            mobile=f"0913{uuid.uuid4().int % 10**7:07d}",
+            password="CheckoutPass!123",
+        )
+        other_token = create_jwt_token(other)
+        other_response = self.client.post(
+            f"/api/events/{self.event.id}/register",
+            data=json.dumps({}),
+            content_type="application/json",
+            HTTP_AUTHORIZATION=f"Bearer {other_token}",
+        )
+
+        assert resume_response.status_code == 200
+        assert resume_response.json()["id"] == registration.id
+        assert other_response.status_code == 400
+        assert "ظرفیت" in other_response.json().get("detail", "")
+
+    def test_active_checkout_remains_resumable_after_registration_closes(self):
+        registration, _ = self.create_pending_checkout()
+        self.event.registration_end_date = timezone.now() - timedelta(minutes=1)
+        self.event.save(update_fields=["registration_end_date"])
+
+        response = self.client.post(
+            f"/api/events/{self.event.id}/register",
+            data=json.dumps({}),
+            content_type="application/json",
+            **self.auth_headers(),
+        )
+
+        assert response.status_code == 200
+        assert response.json()["id"] == registration.id
+
+    def test_registration_status_returns_resumable_payment_without_changing_legacy_flag(self):
+        registration, payment = self.create_pending_checkout()
+
+        response = self.client.get(
+            f"/api/events/{self.event.id}/is-registered",
+            **self.auth_headers(),
+        )
+
+        assert response.status_code == 200
+        payload = response.json()
+        assert payload["is_registered"] is False
+        assert payload["checkout_state"] == "active"
+        assert payload["can_resume"] is True
+        assert payload["registration_id"] == registration.id
+        assert payload["payment_id"] == payment.id
+        expected_expiry = registration.checkout_expires_at.isoformat(timespec="milliseconds").replace("+00:00", "Z")
+        assert payload["checkout_expires_at"] == expected_expiry
+
+    def test_registration_hub_returns_ready_state_for_user_without_registration(self):
+        response = self.client.get(
+            f"/api/events/{self.event.slug}/registration/status",
+            **self.auth_headers(),
+        )
+
+        assert response.status_code == 200
+        payload = response.json()
+        assert payload["state"] == "ready"
+        assert payload["event"]["slug"] == self.event.slug
+        assert payload["registration"] is None
+        assert payload["payment"] is None
+        assert payload["can_register"] is True
+
+    def test_registration_hub_requires_authentication(self):
+        response = self.client.get(f"/api/events/{self.event.slug}/registration/status")
+        assert response.status_code == 401
+
+    def test_registration_hub_does_not_trust_a_status_query_parameter(self):
+        registration = Registration.objects.create(
+            event=self.event,
+            user=self.user,
+            status=Registration.StatusChoices.CONFIRMED,
+            final_price=self.event.price,
+        )
+        Payment.objects.create(
+            user=self.user,
+            event=self.event,
+            registration=registration,
+            base_amount=self.event.price,
+            amount=self.event.price,
+            status=Payment.OrderStatusChoices.PAID,
+            authority=f"AUTH-{uuid.uuid4().hex}",
+        )
+
+        response = self.client.get(
+            f"/api/events/{self.event.slug}/registration/status?status=failed",
+            **self.auth_headers(),
+        )
+
+        assert response.status_code == 200
+        assert response.json()["state"] == "paid_success"
+
+    def test_registration_hub_shows_confirmed_free_registration(self):
+        registration = Registration.objects.create(
+            event=self.event,
+            user=self.user,
+            status=Registration.StatusChoices.CONFIRMED,
+            final_price=0,
+        )
+
+        response = self.client.get(
+            f"/api/events/{self.event.slug}/registration/status",
+            {"registration_id": str(registration.ticket_id)},
+            **self.auth_headers(),
+        )
+
+        assert response.status_code == 200
+        assert response.json()["state"] == "free_success"
+
+    def test_registration_hub_returns_404_for_foreign_payment(self):
+        other = User.objects.create_user(
+            username=f"other-{uuid.uuid4().hex[:8]}",
+            email=f"other-{uuid.uuid4().hex[:8]}@example.com",
+            mobile=f"0913{uuid.uuid4().int % 10**7:07d}",
+            password="CheckoutPass!123",
+        )
+        payment = Payment.objects.create(
+            user=other,
+            event=self.event,
+            base_amount=self.event.price,
+            amount=self.event.price,
+            status=Payment.OrderStatusChoices.PENDING,
+            authority=f"AUTH-{uuid.uuid4().hex}",
+        )
+
+        response = self.client.get(
+            f"/api/events/{self.event.slug}/registration/status",
+            {"payment_id": payment.id},
+            **self.auth_headers(),
+        )
+
+        assert response.status_code == 404
+
+    def test_registration_hub_uses_registration_ticket_uuid_and_exposes_active_payment(self):
+        registration, payment = self.create_pending_checkout()
+
+        response = self.client.get(
+            f"/api/events/{self.event.slug}/registration/status",
+            {"registration_id": str(registration.ticket_id)},
+            **self.auth_headers(),
+        )
+
+        assert response.status_code == 200
+        payload = response.json()
+        assert payload["state"] == "active_checkout"
+        assert payload["registration"]["ticket_id"] == str(registration.ticket_id)
+        assert payload["payment"]["id"] == payment.id
+        assert payload["can_resume"] is True
+        assert payload["can_cancel"] is True
+
+    def test_registration_hub_hides_another_users_registration(self):
+        other = User.objects.create_user(
+            username=f"other-{uuid.uuid4().hex[:8]}",
+            email=f"other-{uuid.uuid4().hex[:8]}@example.com",
+            mobile=f"0913{uuid.uuid4().int % 10**7:07d}",
+            password="CheckoutPass!123",
+        )
+        registration = Registration.objects.create(
+            event=self.event,
+            user=other,
+            status=Registration.StatusChoices.CONFIRMED,
+            final_price=self.event.price,
+        )
+
+        response = self.client.get(
+            f"/api/events/{self.event.slug}/registration/status",
+            {"registration_id": str(registration.ticket_id)},
+            **self.auth_headers(),
+        )
+
+        assert response.status_code == 404
+
+    def test_registration_hub_accepts_legacy_payment_without_linked_registration(self):
+        payment = Payment.objects.create(
+            user=self.user,
+            event=self.event,
+            base_amount=self.event.price,
+            amount=self.event.price,
+            status=Payment.OrderStatusChoices.PENDING,
+            authority=f"AUTH-{uuid.uuid4().hex}",
+        )
+
+        response = self.client.get(
+            f"/api/events/{self.event.slug}/registration/status",
+            {"payment_id": payment.id},
+            **self.auth_headers(),
+        )
+
+        assert response.status_code == 200
+        payload = response.json()
+        assert payload["state"] == "verification_pending"
+        assert payload["registration"] is None
+        assert payload["payment"]["id"] == payment.id
+        assert payload["can_register"] is False
+
+    def test_registration_hub_uses_event_id_for_legacy_events_without_a_slug(self):
+        registration = Registration.objects.create(
+            event=self.event,
+            user=self.user,
+            status=Registration.StatusChoices.CONFIRMED,
+            final_price=self.event.price,
+            confirmation_notification_sent_at=timezone.now(),
+        )
+        payment = Payment.objects.create(
+            user=self.user,
+            event=self.event,
+            registration=registration,
+            base_amount=self.event.price,
+            amount=self.event.price,
+            status=Payment.OrderStatusChoices.PAID,
+            authority=f"AUTH-{uuid.uuid4().hex}",
+        )
+        Event.objects.filter(pk=self.event.pk).update(slug="")
+
+        response = self.client.get(
+            f"/api/events/{self.event.pk}/registration/status",
+            {"payment_id": payment.id},
+            **self.auth_headers(),
+        )
+
+        assert response.status_code == 200
+        payload = response.json()
+        assert payload["state"] == "paid_success"
+        assert payload["event"]["slug"] == ""
+        assert payload["payment"]["id"] == payment.id
+
+    def test_registration_hub_prefers_active_attempt_over_newer_settled_attempt(self):
+        confirmed = Registration.objects.create(
+            event=self.event,
+            user=self.user,
+            status=Registration.StatusChoices.CONFIRMED,
+            final_price=self.event.price,
+        )
+        Payment.objects.create(
+            user=self.user,
+            event=self.event,
+            registration=confirmed,
+            base_amount=self.event.price,
+            amount=self.event.price,
+            status=Payment.OrderStatusChoices.PAID,
+            authority=f"AUTH-{uuid.uuid4().hex}",
+        )
+        active, active_payment = self.create_pending_checkout()
+
+        response = self.client.get(
+            f"/api/events/{self.event.slug}/registration/status",
+            **self.auth_headers(),
+        )
+
+        assert response.status_code == 200
+        payload = response.json()
+        assert payload["state"] == "active_checkout"
+        assert payload["registration"]["ticket_id"] == str(active.ticket_id)
+        assert payload["payment"]["id"] == active_payment.id
+
+    def test_registration_hub_returns_manual_review_and_refund_state_from_saved_records(self):
+        registration, payment = self.create_pending_checkout()
+        payment.verification_manual_review_at = timezone.now()
+        payment.refund_status = Payment.RefundStatusChoices.MANUAL_REVIEW
+        payment.save(update_fields=["verification_manual_review_at", "refund_status"])
+
+        response = self.client.get(
+            f"/api/events/{self.event.slug}/registration/status",
+            {"payment_id": payment.id},
+            **self.auth_headers(),
+        )
+
+        assert response.status_code == 200
+        payload = response.json()
+        assert payload["state"] == "refund_manual_review"
+        assert payload["registration"]["ticket_id"] == str(registration.ticket_id)
+        assert payload["payment"]["verification_state"] == "manual_review"
+        assert payload["payment"]["refund_status"] == "manual_review"
+
+    def test_expired_unresolved_checkout_releases_registration_and_blocks_duplicate_payment(self):
+        expired_at = timezone.now() - timedelta(seconds=1)
+        registration, payment = self.create_pending_checkout(expires_at=expired_at)
+
+        response = self.client.post(
+            "/api/payments/create",
+            data=json.dumps({
+                "event_id": self.event.id,
+                "description": "Retry after abandoned checkout",
+                "idempotency_key": str(uuid.uuid4()),
+            }),
+            content_type="application/json",
+            **self.auth_headers(),
+        )
+
+        registration.refresh_from_db()
+        payment.refresh_from_db()
+        assert response.status_code == 409
+        assert registration.status == Registration.StatusChoices.CANCELLED
+        assert registration.cancellation_reason == Registration.CancellationReasonChoices.CHECKOUT_EXPIRED
+        assert payment.status == Payment.OrderStatusChoices.PENDING
+        assert Payment.objects.filter(event=self.event, user=self.user).count() == 1
+
+    def test_expiry_sweep_cancels_only_new_expired_checkouts_and_releases_the_seat(self):
+        expired_at = timezone.now() - timedelta(seconds=1)
+        registration, payment = self.create_pending_checkout(expires_at=expired_at)
+        legacy = Registration.objects.create(
+            event=self.event,
+            user=User.objects.create_user(
+                username=f"legacy-{uuid.uuid4().hex[:8]}",
+                email=f"legacy-{uuid.uuid4().hex[:8]}@example.com",
+                mobile=f"0914{uuid.uuid4().int % 10**7:07d}",
+                password="CheckoutPass!123",
+            ),
+            status=Registration.StatusChoices.PENDING,
+            final_price=self.event.price,
+        )
+
+        count = expire_stale_registration_checkouts()
+
+        registration.refresh_from_db()
+        payment.refresh_from_db()
+        legacy.refresh_from_db()
+        assert count == 1
+        assert registration.status == Registration.StatusChoices.CANCELLED
+        assert registration.cancellation_reason == Registration.CancellationReasonChoices.CHECKOUT_EXPIRED
+        assert payment.status == Payment.OrderStatusChoices.PENDING
+        assert Event.objects.get(pk=self.event.pk).current_attendees_count == 0
+        assert legacy.status == Registration.StatusChoices.PENDING
+
+    def test_user_can_cancel_active_checkout_without_deleting_registration(self, mocker):
+        registration, payment = self.create_pending_checkout()
+        mocker.patch("apps.payments.tasks.reconcile_payment.apply_async")
+
+        response = self.client.post(
+            f"/api/events/{self.event.id}/checkout/cancel",
+            **self.auth_headers(),
+        )
+
+        registration.refresh_from_db()
+        payment.refresh_from_db()
+        assert response.status_code == 200
+        assert registration.status == Registration.StatusChoices.CANCELLED
+        assert registration.cancellation_reason == Registration.CancellationReasonChoices.USER_CANCELLED
+        assert Registration.objects.filter(pk=registration.pk).exists()
+        assert payment.status == Payment.OrderStatusChoices.PENDING
+        assert Event.objects.get(pk=self.event.pk).current_attendees_count == 0
+
+    def test_new_checkout_is_blocked_while_late_payment_refund_is_unresolved(self):
+        registration = Registration.objects.create(
+            event=self.event,
+            user=self.user,
+            status=Registration.StatusChoices.CANCELLED,
+            cancellation_reason=Registration.CancellationReasonChoices.CHECKOUT_EXPIRED,
+            checkout_started_at=timezone.now() - timedelta(minutes=20),
+            checkout_expires_at=timezone.now() - timedelta(minutes=5),
+            final_price=self.event.price,
+        )
+        Payment.objects.create(
+            user=self.user,
+            event=self.event,
+            registration=registration,
+            base_amount=self.event.price,
+            amount=self.event.price,
+            status=Payment.OrderStatusChoices.PAID,
+            refund_status=Payment.RefundStatusChoices.PENDING,
+            authority=f"AUTH-{uuid.uuid4().hex}",
+        )
+
+        register_response = self.client.post(
+            f"/api/events/{self.event.id}/register",
+            data=json.dumps({}),
+            content_type="application/json",
+            **self.auth_headers(),
+        )
+        payment_response = self.client.post(
+            "/api/payments/create",
+            data=json.dumps({
+                "event_id": self.event.id,
+                "description": "Do not charge twice while refund is unresolved",
+                "idempotency_key": str(uuid.uuid4()),
+            }),
+            content_type="application/json",
+            **self.auth_headers(),
+        )
+
+        assert register_response.status_code == 409
+        assert payment_response.status_code == 409
+        assert Registration.objects.filter(event=self.event, user=self.user).count() == 1
+
+    def test_event_cancellation_ends_checkouts_and_queues_payment_reconciliation(self, mocker):
+        registration, payment = self.create_pending_checkout()
+        enqueue = mocker.patch("apps.payments.tasks.reconcile_payment.apply_async")
+        mocker.patch("apps.events.checkout.transaction.on_commit", side_effect=lambda callback: callback())
+        self.event.status = Event.StatusChoices.CANCELLED
+        self.event.save(update_fields=["status"])
+
+        cancelled = cancel_event_checkouts(self.event.id)
+
+        registration.refresh_from_db()
+        assert cancelled == 1
+        assert registration.status == Registration.StatusChoices.CANCELLED
+        assert registration.cancellation_reason == Registration.CancellationReasonChoices.EVENT_CANCELLED
+        assert Event.objects.get(pk=self.event.pk).current_attendees_count == 0
+        enqueue.assert_called_once_with(args=(payment.id,), countdown=0)

apps/events/tests/unit/test_admin_actions.py

@@ -22,13 +22,21 @@ def test_event_admin_formats_empty_price_and_capacity():
 def test_event_admin_status_actions_update_selection(mocker):
     model_admin = EventAdmin(Event, admin.site)
     mocker.patch.object(model_admin, "message_user")
+    cancel_checkouts = mocker.patch("apps.events.admin.cancel_event_checkouts")
     queryset = mocker.Mock()
     queryset.count.return_value = 2
     for action, status in (
         (model_admin.make_published, Event.StatusChoices.PUBLISHED),
         (model_admin.make_draft, Event.StatusChoices.DRAFT),
-        (model_admin.make_cancelled, Event.StatusChoices.CANCELLED),
         (model_admin.make_completed, Event.StatusChoices.COMPLETED),
     ):
         action(SimpleNamespace(), queryset)
         queryset.update.assert_called_with(status=status)
+
+    published = SimpleNamespace(status=Event.StatusChoices.PUBLISHED, pk=10, save=mocker.Mock())
+    already_cancelled = SimpleNamespace(status=Event.StatusChoices.CANCELLED, pk=11, save=mocker.Mock())
+    model_admin.make_cancelled(SimpleNamespace(), [published, already_cancelled])
+
+    published.save.assert_called_once_with(update_fields=["status"])
+    already_cancelled.save.assert_not_called()
+    cancel_checkouts.assert_called_once_with(published.pk)

apps/payments/admin.py

@@ -52,18 +52,26 @@ class PaymentAdmin(BaseModelAdmin, ImportExportModelAdmin):
     
     list_display = (
         'id', 'user', 'event', 'base_amount', 'discount_code', 'discount_amount', 'amount',
-        'status', 'created_at', 'verified_at', 'is_deleted'
+        'status', 'refund_status', 'refund_attempts', 'verification_attempts',
+        'verification_manual_review_at',
+        'created_at', 'verified_at', 'is_deleted'
     )
     list_filter = (
-        'status', 'event',
+        'status', 'refund_status', 'event', 'verification_manual_review_at',
         SoftDeleteListFilter,
     )
     search_fields = (
         'user__email', 'authority', 'ref_id', 'discount_code__code'
     )
     readonly_fields = (
-        'user', 'event', 'base_amount', 'discount_code', 'discount_code', 'discount_amount', 'amount', 'authority',
+        'user', 'event', 'base_amount', 'discount_code', 'discount_amount', 'amount', 'authority',
-        'status', 'ref_id', 'card_pan', 'card_hash', 'created_at', 'updated_at', 'deleted_at'
+        'status', 'ref_id', 'card_pan', 'card_hash', 'verified_at', 'gateway_paid_at',
+        'verification_attempts',
+        'verification_last_attempt_at', 'verification_next_attempt_at', 'verification_lease_until',
+        'verification_dispatch_expires_at', 'verification_manual_review_at', 'idempotency_key',
+        'refund_status', 'refund_attempts', 'refund_last_attempt_at', 'refund_next_attempt_at',
+        'refund_reference', 'refund_last_error',
+        'created_at', 'updated_at', 'deleted_at'
     )
 
     fieldsets = (
@@ -74,7 +82,20 @@ class PaymentAdmin(BaseModelAdmin, ImportExportModelAdmin):
             'fields': ('base_amount', 'discount_code', 'discount_amount', 'amount')
         }),
         ('Others', {
-            'fields': ('authority', 'ref_id', 'card_pan', 'card_hash')
+            'fields': ('authority', 'ref_id', 'card_pan', 'card_hash', 'verified_at', 'gateway_paid_at', 'idempotency_key')
+        }),
+        ('Verification and Support Review', {
+            'fields': (
+                'verification_attempts', 'verification_last_attempt_at',
+                'verification_next_attempt_at', 'verification_lease_until',
+                'verification_dispatch_expires_at', 'verification_manual_review_at',
+            )
+        }),
+        ('Refund and Reversal Review', {
+            'fields': (
+                'refund_status', 'refund_attempts', 'refund_last_attempt_at',
+                'refund_next_attempt_at', 'refund_reference', 'refund_last_error',
+            )
         }),
         ('Soft Delete', {
             'fields': ('is_deleted', 'deleted_at'),

apps/payments/api/schemas.py

@@ -71,21 +71,44 @@ class PaymentDetailOut(Schema):
     amount: int
     status: str
     verified_at: str | None = None
+    gateway_paid_at: str | None = None
+    refund_status: Literal["none", "pending", "succeeded", "manual_review"] = "none"
+    refund_attempts: int = 0
+    refund_last_attempt_at: str | None = None
+    refund_next_attempt_at: str | None = None
+    refund_reference: str | None = None
+    refund_last_error: str | None = None
+    verification_state: Literal[
+        "awaiting_verification",
+        "checking",
+        "retry_scheduled",
+        "manual_review",
+        "verified",
+        "failed",
+        "canceled",
+    ]
+    verification_attempts: int
+    last_verification_at: str | None = None
+    next_verification_at: str | None = None
+    manual_review_at: str | None = None
     event: dict
 
 
 class UserPaymentEventSchema(Schema):
+    id: int
     title: str
     slug: str
     image_url: Optional[str] = None
 
 
 class UserPaymentSchema(Schema):
+    payment_id: int
     event: UserPaymentEventSchema
     base_amount: int
     discount_amount: int
     amount: int
     status: Literal["initiated", "pending", "paid", "failed", "canceled"]
+    refund_status: Literal["none", "pending", "succeeded", "manual_review"] = "none"
     created_at: datetime
     paid_at: Optional[datetime] = None
 

apps/payments/api/views.py

@@ -1,5 +1,7 @@
 import logging
+from datetime import datetime
 from uuid import uuid4
+from urllib.parse import quote
 
 from django.conf import settings
 from django.shortcuts import redirect, get_object_or_404
@@ -14,8 +16,18 @@ import requests
 
 from apps.payments.models import Payment, DiscountCode
 from apps.events.models import Event, Registration
+from apps.events.checkout import (
+    CHECKOUT_TIMEOUT,
+    expire_stale_registration_checkouts,
+    queue_checkout_reconciliation,
+)
 from apps.notifications.services import notify_user
-from apps.payments.services import PaymentVerificationUncertain, request_payment_verification
+from apps.payments.services import (
+    PaymentVerificationUncertain,
+    claim_payment_verification,
+    request_payment_verification,
+    schedule_payment_verification_retry,
+)
 from apps.payments.tasks import reconcile_payment
 from apps.users.tasks import send_critical_sms
 from core.authentication import jwt_auth
@@ -55,7 +67,9 @@ def my_payments(request):
 
 def _user_payment_payload(request, payment, status_names):
     return {
+        "payment_id": payment.id,
         "event": {
+            "id": payment.event_id,
             "title": payment.event.title,
             "slug": payment.event.slug,
             "image_url": request.build_absolute_uri(payment.event.featured_image.url)
@@ -66,6 +80,7 @@ def _user_payment_payload(request, payment, status_names):
         "discount_amount": payment.discount_amount,
         "amount": payment.amount,
         "status": status_names[payment.status],
+        "refund_status": payment.refund_status,
         "created_at": payment.created_at,
         "paid_at": payment.verified_at,
     }
@@ -270,9 +285,38 @@ def _payment_checkout_payload(payment: Payment):
     }
 
 
+def _ensure_checkout_attempt_can_be_reused(payment: Payment, *, now, allow_review_replay=False):
+    registration = payment.registration
+    if registration is None:
+        return
+
+    if payment.verification_manual_review_at is not None and not allow_review_replay:
+        raise HttpError(409, "وضعیت پرداخت در حال بررسی پشتیبانی است و امکان شروع دوباره وجود ندارد.")
+
+    if (
+        registration.status == Registration.StatusChoices.PENDING
+        and registration.checkout_expires_at is not None
+        and registration.checkout_expires_at <= now
+    ):
+        raise HttpError(409, "مهلت پرداخت این ثبت‌نام به پایان رسیده است.")
+
+    if (
+        registration.status == Registration.StatusChoices.CANCELLED
+        and registration.cancellation_reason in {
+            Registration.CancellationReasonChoices.CHECKOUT_EXPIRED,
+            Registration.CancellationReasonChoices.USER_CANCELLED,
+            Registration.CancellationReasonChoices.EVENT_CANCELLED,
+        }
+        and payment.status in (Payment.OrderStatusChoices.INIT, Payment.OrderStatusChoices.PENDING)
+    ):
+        raise HttpError(409, "وضعیت پرداخت قبلی هنوز مشخص نشده است. پس از بررسی دوباره تلاش کنید.")
+
+
 @payments_router.post("create", response=CreatePaymentOut, auth=jwt_auth)
 def create_payment(request, payload: CreatePaymentIn):
     idempotency_key = payload.idempotency_key or uuid4()
+    now = timezone.now()
+    expire_stale_registration_checkouts(now=now, event_id=payload.event_id)
 
     # Serialize checkout creation for this event so concurrent taps cannot
     # both create a new active attempt for the same user/event pair.
@@ -282,19 +326,48 @@ def create_payment(request, payload: CreatePaymentIn):
             pk=payload.event_id,
             is_deleted=False,
         )
+        if event.status == Event.StatusChoices.CANCELLED:
+            raise HttpError(400, "این رویداد لغو شده است و امکان پرداخت ندارد.")
 
         keyed_payment = Payment.objects.filter(
             user=request.auth,
             event=event,
             idempotency_key=idempotency_key,
-        ).select_related("event").first()
+        ).select_related("event", "registration").first()
         if keyed_payment:
+            _ensure_checkout_attempt_can_be_reused(
+                keyed_payment,
+                now=now,
+                allow_review_replay=True,
+            )
             return _payment_checkout_payload(keyed_payment)
 
+        unresolved_refund = Payment.objects.filter(
+            user=request.auth,
+            event=event,
+            registration__cancellation_reason__in=[
+                Registration.CancellationReasonChoices.CHECKOUT_EXPIRED,
+                Registration.CancellationReasonChoices.USER_CANCELLED,
+                Registration.CancellationReasonChoices.EVENT_CANCELLED,
+            ],
+            status=Payment.OrderStatusChoices.PAID,
+            refund_status__in=[
+                Payment.RefundStatusChoices.PENDING,
+                Payment.RefundStatusChoices.MANUAL_REVIEW,
+            ],
+        ).exists()
+        if unresolved_refund:
+            raise HttpError(409, "بازگشت وجه پرداخت قبلی هنوز نهایی نشده است. پس از بررسی دوباره تلاش کنید.")
+
         if Payment.objects.filter(
             status=Payment.OrderStatusChoices.PAID,
             user=request.auth,
             event=event,
+            refund_status__in=[
+                Payment.RefundStatusChoices.NONE,
+                Payment.RefundStatusChoices.PENDING,
+                Payment.RefundStatusChoices.MANUAL_REVIEW,
+            ],
         ).exists():
             raise HttpError(400, "You have already registered in this event")
 
@@ -304,10 +377,12 @@ def create_payment(request, payload: CreatePaymentIn):
                 event=event,
                 status__in=[Payment.OrderStatusChoices.INIT, Payment.OrderStatusChoices.PENDING],
             )
+            .select_related("registration")
             .order_by("-created_at", "-id")
             .first()
         )
         if active_payment:
+            _ensure_checkout_attempt_can_be_reused(active_payment, now=now)
             return _payment_checkout_payload(active_payment)
 
         registration = (
@@ -316,11 +391,29 @@ def create_payment(request, payload: CreatePaymentIn):
             .order_by("-registered_at")
             .first()
         )
+        if registration and registration.status in (
+            Registration.StatusChoices.CONFIRMED,
+            Registration.StatusChoices.ATTENDED,
+        ):
+            raise HttpError(400, "شما قبلا در این ایونت ثبت‌نام کرده‌اید.")
+
+        needs_new_checkout = not registration or registration.status == Registration.StatusChoices.CANCELLED
+        if needs_new_checkout:
+            if event.status != Event.StatusChoices.PUBLISHED:
+                raise HttpError(400, "ثبت‌نام این رویداد فعال نیست.")
+            if event.registration_start_date and event.registration_start_date > now:
+                raise HttpError(400, "زمان ثبت‌نام هنوز آغاز نشده است")
+            if event.registration_end_date and event.registration_end_date < now:
+                raise HttpError(400, "مهلت ثبت‌نام به پایان رسیده‌است")
+            if not event.has_available_slots:
+                raise HttpError(400, "ظرفیت شرکت‌کنندگان تکمیل است")
         if not registration or registration.status == Registration.StatusChoices.CANCELLED:
             registration = Registration.objects.create(
                 event=event,
                 user=request.auth,
                 status=Registration.StatusChoices.PENDING,
+                checkout_started_at=now,
+                checkout_expires_at=now + CHECKOUT_TIMEOUT,
                 final_price=event.price,
             )
         elif registration.final_price is None:
@@ -331,7 +424,17 @@ def create_payment(request, payload: CreatePaymentIn):
         discount_amount = 0
         final_amount = event.price
 
-        if payload.discount_code:
+        if (
+            registration.status == Registration.StatusChoices.PENDING
+            and registration.final_price is not None
+            and (registration.discount_code_id or not payload.discount_code)
+        ):
+            # Resume with the persisted quote; a browser reload must not lose a
+            # coupon or silently change the amount agreed when the seat was held.
+            discount_code = registration.discount_code
+            discount_amount = registration.discount_amount
+            final_amount = registration.final_price
+        elif payload.discount_code:
             discount_code = DiscountCode.objects.filter(
                 code=payload.discount_code,
                 applicable_events=event,
@@ -421,7 +524,8 @@ def create_payment(request, payload: CreatePaymentIn):
             pay.id,
         )
         pay.status = Payment.OrderStatusChoices.PENDING
-        pay.save(update_fields=["status"])
+        pay.verification_manual_review_at = timezone.now()
+        pay.save(update_fields=["status", "verification_manual_review_at"])
         return _payment_checkout_payload(pay)
 
     data = jd.get("data") if isinstance(jd, dict) else None
@@ -441,31 +545,122 @@ def create_payment(request, payload: CreatePaymentIn):
                 pay.id,
             )
             pay.status = Payment.OrderStatusChoices.PENDING
-            pay.save(update_fields=["status"])
+            pay.verification_manual_review_at = timezone.now()
+            pay.save(update_fields=["status", "verification_manual_review_at"])
         return _payment_checkout_payload(pay)
 
-    pay.authority = authority
+    with transaction.atomic():
-    pay.status = Payment.OrderStatusChoices.PENDING
+        event = Event.objects.select_for_update().get(pk=pay.event_id)
-    pay.save(update_fields=["authority","status"])
+        registration = None
+        if pay.registration_id:
+            registration = Registration.objects.select_for_update().filter(pk=pay.registration_id).first()
+        pay = Payment.objects.select_for_update().get(pk=pay.id)
+        pay.authority = authority
+        if pay.status in (Payment.OrderStatusChoices.INIT, Payment.OrderStatusChoices.PENDING):
+            pay.status = Payment.OrderStatusChoices.PENDING
+            pay.verification_manual_review_at = None
+            pay.save(update_fields=["authority", "status", "verification_manual_review_at"])
+        if (
+            registration is not None
+            and registration.status == Registration.StatusChoices.CANCELLED
+        ) or event.status == Event.StatusChoices.CANCELLED:
+            if registration is not None:
+                queue_checkout_reconciliation(registration)
 
     return _payment_checkout_payload(pay)
 
-def _callback_redirect(payment: Payment, status: str):
+def _frontend_root_url():
-    url = (
+    root = (getattr(settings, "FRONTEND_ROOT", "") or settings.FRONTEND_CALLBACK_URL).rstrip("/")
-        f"{settings.FRONTEND_CALLBACK_URL}?status={status}"
+    return root
-        f"&event_id={payment.event_id}&payment_id={payment.id}"
+
-    )
+
-    if status == "success" and payment.ref_id:
+def _callback_redirect(payment: Payment, _status: str):
-        url += f"&ref_id={payment.ref_id}"
+    """Return to the authenticated hub; its API read is the status authority."""
+    event = payment.event
+    url = f"{_frontend_root_url()}/events/{quote(event.slug or str(event.id), safe='')}/registration"
+    if payment.registration_id:
+        url += f"?registration_id={payment.registration.ticket_id}"
+    else:
+        url += f"?payment_id={payment.id}"
     return redirect(url)
 
 
+def _callback_unknown_redirect():
+    """Send malformed or stale provider callbacks to the designed safe fallback."""
+    return redirect(f"{_frontend_root_url()}/events?payment_callback=unmatched")
+
+
+def _provider_paid_at(verification_data: dict | None):
+    """Read an explicit timezone-aware payment time if the gateway supplies one."""
+    raw_value = verification_data.get("paid_at") if isinstance(verification_data, dict) else None
+    if isinstance(raw_value, datetime):
+        return raw_value if timezone.is_aware(raw_value) else None
+    if not isinstance(raw_value, str) or not raw_value.strip():
+        return None
+    try:
+        value = datetime.fromisoformat(raw_value.strip().replace("Z", "+00:00"))
+    except ValueError:
+        return None
+    return value if timezone.is_aware(value) else None
+
+
+def _checkout_may_be_confirmed(event, registration, paid_at, now):
+    if registration is None:
+        return False
+    if registration.status in (
+        Registration.StatusChoices.CONFIRMED,
+        Registration.StatusChoices.ATTENDED,
+    ):
+        return True
+    if event.status == Event.StatusChoices.CANCELLED:
+        return False
+
+    expiry = registration.checkout_expires_at
+    if registration.status == Registration.StatusChoices.PENDING:
+        if registration.cancellation_reason:
+            return False
+        if expiry is None or expiry > now:
+            return True
+
+    if (
+        registration.status == Registration.StatusChoices.CANCELLED
+        and registration.cancellation_reason == Registration.CancellationReasonChoices.CHECKOUT_EXPIRED
+        and expiry is not None
+        and paid_at is not None
+        and paid_at <= expiry
+        and event.has_available_slots
+    ):
+        return True
+    return False
+
+
+def _queue_payment_refund(payment_id):
+    from apps.payments.tasks import refund_payment
+
+    def dispatch():
+        try:
+            refund_payment.apply_async(args=(payment_id,), countdown=0)
+        except Exception:
+            logger.exception("Unable to dispatch refund reversal for payment %s", payment_id)
+
+    transaction.on_commit(
+        dispatch
+    )
+
+
 def _mark_payment_paid(payment_id: int, verification_data: dict | None = None):
-    """Persist a verified payment and its registration as one idempotent transition."""
+    """Persist provider success without reviving a cancelled checkout by accident."""
+    payment_snapshot = Payment.objects.only("event_id", "registration_id").get(pk=payment_id)
+    paid_at = _provider_paid_at(verification_data)
     with transaction.atomic():
+        event = Event.objects.select_for_update().get(pk=payment_snapshot.event_id)
+        registration = None
+        if payment_snapshot.registration_id:
+            registration = Registration.objects.select_for_update().filter(
+                pk=payment_snapshot.registration_id
+            ).first()
         payment = (
             Payment.objects.select_for_update()
-            .select_related("event", "user")
             .get(pk=payment_id)
         )
         was_already_verified = (
@@ -483,27 +678,63 @@ def _mark_payment_paid(payment_id: int, verification_data: dict | None = None):
             payment.card_hash = verification_data.get("card_hash")
             payment.verified_at = timezone.now()
             updates.extend(["ref_id", "card_pan", "card_hash", "verified_at"])
+        if paid_at is not None and payment.gateway_paid_at is None:
+            payment.gateway_paid_at = paid_at
+            updates.append("gateway_paid_at")
+        for field in (
+            "verification_next_attempt_at",
+            "verification_lease_until",
+            "verification_dispatch_expires_at",
+            "verification_manual_review_at",
+        ):
+            if getattr(payment, field) is not None:
+                setattr(payment, field, None)
+                updates.append(field)
         if updates:
             payment.save(update_fields=updates)
 
-        registration = None
+        now = timezone.now()
-        if payment.registration_id:
+        if registration and registration.status == Registration.StatusChoices.PENDING:
-            registration = Registration.objects.select_for_update().filter(
+            if event.status == Event.StatusChoices.CANCELLED:
-                pk=payment.registration_id
+                registration.status = Registration.StatusChoices.CANCELLED
-            ).first()
+                registration.cancellation_reason = Registration.CancellationReasonChoices.EVENT_CANCELLED
-        if registration is None:
+                registration.save(update_fields=["status", "cancellation_reason", "updated_at"])
-            registration = Registration.objects.select_for_update().filter(
+            elif (
-                user_id=payment.user_id,
+                registration.checkout_expires_at is not None
-                event_id=payment.event_id,
+                and registration.checkout_expires_at <= now
-                status=Registration.StatusChoices.PENDING,
+                and not registration.cancellation_reason
-            ).first()
+            ):
-        if registration and registration.status != Registration.StatusChoices.CONFIRMED:
+                registration.status = Registration.StatusChoices.CANCELLED
-            registration.status = Registration.StatusChoices.CONFIRMED
+                registration.cancellation_reason = Registration.CancellationReasonChoices.CHECKOUT_EXPIRED
-            registration_updates = ["status"]
+                registration.save(update_fields=["status", "cancellation_reason", "updated_at"])
+
+        if _checkout_may_be_confirmed(event, registration, paid_at, now):
+            if registration.status == Registration.StatusChoices.CANCELLED:
+                registration.cancellation_reason = ""
+                registration.status = Registration.StatusChoices.CONFIRMED
+                registration_updates = ["status", "cancellation_reason"]
+            else:
+                registration.status = Registration.StatusChoices.CONFIRMED
+                registration_updates = ["status"]
             if registration.final_price is None:
                 registration.final_price = payment.amount
                 registration_updates.append("final_price")
             registration.save(update_fields=registration_updates)
+            if payment.refund_status != Payment.RefundStatusChoices.NONE:
+                payment.refund_status = Payment.RefundStatusChoices.NONE
+                payment.refund_last_error = ""
+                payment.refund_next_attempt_at = None
+                payment.save(update_fields=[
+                    "refund_status", "refund_last_error", "refund_next_attempt_at",
+                ])
+        elif not was_already_verified and payment.refund_status not in (
+            Payment.RefundStatusChoices.SUCCEEDED,
+            Payment.RefundStatusChoices.MANUAL_REVIEW,
+        ):
+            payment.refund_status = Payment.RefundStatusChoices.PENDING
+            payment.refund_next_attempt_at = None
+            payment.save(update_fields=["refund_status", "refund_next_attempt_at"])
+            _queue_payment_refund(payment.id)
 
     return payment, not was_already_verified
 
@@ -516,7 +747,11 @@ def _mark_payment_pending(payment_id: int):
             if payment.status != Payment.OrderStatusChoices.PAID:
                 payment.status = Payment.OrderStatusChoices.PAID
                 payment.save(update_fields=["status"])
-        elif payment.status in (Payment.OrderStatusChoices.INIT, Payment.OrderStatusChoices.CANCELED):
+        elif payment.status in (
+            Payment.OrderStatusChoices.INIT,
+            Payment.OrderStatusChoices.FAILED,
+            Payment.OrderStatusChoices.CANCELED,
+        ):
             payment.status = Payment.OrderStatusChoices.PENDING
             payment.save(update_fields=["status"])
     return payment
@@ -524,10 +759,16 @@ def _mark_payment_pending(payment_id: int):
 
 def _mark_payment_unsuccessful(payment_id: int, target_status: int):
     """Apply a failure only while the payment has not been verified successfully."""
+    snapshot = Payment.objects.only("event_id", "registration_id", "user_id").get(pk=payment_id)
     with transaction.atomic():
+        Event.objects.select_for_update().get(pk=snapshot.event_id)
+        registration = None
+        if snapshot.registration_id:
+            registration = Registration.objects.select_for_update().filter(
+                pk=snapshot.registration_id,
+            ).first()
         payment = (
             Payment.objects.select_for_update()
-            .select_related("event", "user")
             .get(pk=payment_id)
         )
         if (
@@ -551,7 +792,17 @@ def _mark_payment_unsuccessful(payment_id: int, target_status: int):
             transitioned = False
         else:
             payment.status = target_status
-            payment.save(update_fields=["status"])
+            payment.verification_next_attempt_at = None
+            payment.verification_lease_until = None
+            payment.verification_dispatch_expires_at = None
+            payment.verification_manual_review_at = None
+            payment.save(update_fields=[
+                "status",
+                "verification_next_attempt_at",
+                "verification_lease_until",
+                "verification_dispatch_expires_at",
+                "verification_manual_review_at",
+            ])
             result = (
                 "canceled"
                 if target_status == Payment.OrderStatusChoices.CANCELED
@@ -559,13 +810,7 @@ def _mark_payment_unsuccessful(payment_id: int, target_status: int):
             )
             transitioned = True
 
-            registration = None
+            if registration is None:
-            if payment.registration_id:
-                registration = Registration.objects.select_for_update().filter(
-                    pk=payment.registration_id,
-                    status=Registration.StatusChoices.PENDING,
-                ).first()
-            else:
                 registration = Registration.objects.select_for_update().filter(
                     user_id=payment.user_id,
                     event_id=payment.event_id,
@@ -589,7 +834,10 @@ def _mark_payment_unsuccessful(payment_id: int, target_status: int):
                     Registration.objects.filter(
                         pk=registration.pk,
                         status=Registration.StatusChoices.PENDING,
-                    ).update(status=Registration.StatusChoices.CANCELLED)
+                    ).update(
+                        status=Registration.StatusChoices.CANCELLED,
+                        cancellation_reason=Registration.CancellationReasonChoices.PAYMENT_FAILED,
+                    )
 
     return payment, result, transitioned
 
@@ -597,49 +845,96 @@ def _mark_payment_unsuccessful(payment_id: int, target_status: int):
 @payments_router.get("callback")
 def callback(request, Authority: str | None = None, Status: str | None = None):
     if not Authority:
-        raise HttpError(400, "Missing Authority")
+        return _callback_unknown_redirect()
 
     pay = Payment.objects.filter(authority=Authority).select_related("event","user","discount_code").first()
     if not pay:
-        raise HttpError(404, "Payment not found")
+        return _callback_unknown_redirect()
+    gateway_says_success = (Status or "").strip().upper() == "OK"
     if pay.status == Payment.OrderStatusChoices.PAID or pay.verified_at is not None:
         pay, _ = _mark_payment_paid(pay.id)
         return _callback_redirect(pay, "success")
+    if pay.status in (
+        Payment.OrderStatusChoices.FAILED,
+        Payment.OrderStatusChoices.CANCELED,
+    ) and not gateway_says_success:
+        return _callback_redirect(pay, _payment_status_name(pay))
+
+    pay, claimed = claim_payment_verification(
+        pay.id,
+        allow_terminal=gateway_says_success,
+        allow_manual_review=gateway_says_success,
+    )
+    if not claimed:
+        return _callback_redirect(pay, _payment_status_name(pay))
 
     try:
         vcode, data = request_payment_verification(pay)
     except PaymentVerificationUncertain:
         pay = _mark_payment_pending(pay.id)
-        if pay.status == Payment.OrderStatusChoices.PENDING and pay.authority:
+        delay = schedule_payment_verification_retry(pay.id)
+        pay.refresh_from_db()
+        if delay is not None and pay.status == Payment.OrderStatusChoices.PENDING:
             try:
-                reconcile_payment.apply_async(args=(pay.id,), countdown=60)
+                reconcile_payment.apply_async(args=(pay.id,), countdown=delay)
             except Exception:
                 logger.exception(
-                    "Unable to queue payment verification retry for payment %s; it remains pending for manual review",
+                    "Unable to queue payment verification retry for payment %s; the recovery sweep will retry it",
                     pay.id,
                 )
+        elif delay is None and pay.status == Payment.OrderStatusChoices.PENDING:
+            logger.error(
+                "Payment %s remains pending after exhausting verification attempts; manual review is required",
+                pay.id,
+            )
         return _callback_redirect(pay, _payment_status_name(pay))
 
     if vcode in (100, 101):
         pay, newly_verified = _mark_payment_paid(pay.id, data)
 
         if newly_verified:
+            refund_pending = pay.refund_status in (
+                Payment.RefundStatusChoices.PENDING,
+                Payment.RefundStatusChoices.MANUAL_REVIEW,
+            )
             _notify_payment_status(
                 pay,
-                title=f"پرداخت رویداد «{pay.event.title}» تأیید شد",
+                title=(
-                message="پرداخت شما با موفقیت ثبت شد و ثبت‌نام رویداد تکمیل شده است.",
+                    f"پرداخت رویداد «{pay.event.title}» تأیید شد؛ بازگشت وجه در حال پیگیری است"
-                level="success",
+                    if refund_pending
+                    else f"پرداخت رویداد «{pay.event.title}» تأیید شد"
+                ),
+                message=(
+                    "ثبت‌نام لغو شده است. بازگشت وجه به‌صورت خودکار پیگیری می‌شود؛ اگر نتیجه روشن نشود، پشتیبانی آن را بررسی می‌کند."
+                    if refund_pending
+                    else "پرداخت شما با موفقیت ثبت شد و ثبت‌نام رویداد تکمیل شده است."
+                ),
+                level="warning" if refund_pending else "success",
             )
 
         return _callback_redirect(pay, "success")
 
-    pay, result, transitioned = _mark_payment_unsuccessful(pay.id, Payment.OrderStatusChoices.FAILED)
+    target_status = (
+        Payment.OrderStatusChoices.CANCELED
+        if (Status or "").strip().upper() == "NOK"
+        else Payment.OrderStatusChoices.FAILED
+    )
+    pay, result, transitioned = _mark_payment_unsuccessful(pay.id, target_status)
     if transitioned:
+        canceled = result == "canceled"
         _notify_payment_status(
             pay,
-            title=f"پرداخت رویداد «{pay.event.title}» ناموفق بود",
+            title=(
-            message="تراکنش شما توسط درگاه تأیید نشد. در صورت نیاز دوباره پرداخت را انجام دهید.",
+                f"پرداخت رویداد «{pay.event.title}» لغو شد"
-            level="error",
+                if canceled
+                else f"پرداخت رویداد «{pay.event.title}» ناموفق بود"
+            ),
+            message=(
+                "پرداخت تکمیل نشد و ثبت‌نام نهایی نشد. برای شروع دوباره به صفحه رویداد برگردید."
+                if canceled
+                else "تراکنش شما توسط درگاه تأیید نشد. در صورت نیاز دوباره پرداخت را انجام دهید."
+            ),
+            level="warning" if canceled else "error",
         )
     return _callback_redirect(pay, result)
 
@@ -666,6 +961,34 @@ def _payment_detail_payload(request, payment: Payment):
         "amount": payment.amount,
         "status": _payment_status_name(payment),
         "verified_at": payment.verified_at.isoformat() if payment.verified_at else None,
+        "gateway_paid_at": payment.gateway_paid_at.isoformat() if payment.gateway_paid_at else None,
+        "refund_status": payment.refund_status,
+        "refund_attempts": payment.refund_attempts,
+        "refund_last_attempt_at": (
+            payment.refund_last_attempt_at.isoformat() if payment.refund_last_attempt_at else None
+        ),
+        "refund_next_attempt_at": (
+            payment.refund_next_attempt_at.isoformat() if payment.refund_next_attempt_at else None
+        ),
+        "refund_reference": payment.refund_reference,
+        "refund_last_error": payment.refund_last_error or None,
+        "verification_state": payment.verification_state,
+        "verification_attempts": payment.verification_attempts,
+        "last_verification_at": (
+            payment.verification_last_attempt_at.isoformat()
+            if payment.verification_last_attempt_at
+            else None
+        ),
+        "next_verification_at": (
+            payment.verification_next_attempt_at.isoformat()
+            if payment.verification_next_attempt_at
+            else None
+        ),
+        "manual_review_at": (
+            payment.verification_manual_review_at.isoformat()
+            if payment.verification_manual_review_at
+            else None
+        ),
         "event": {
             "id": event.id,
             "title": event.title,
@@ -676,9 +999,13 @@ def _payment_detail_payload(request, payment: Payment):
     }
 
 
-@payments_router.get("by-ref/{ref_id}", response=PaymentDetailOut)
+@payments_router.get("by-ref/{ref_id}", response=PaymentDetailOut, auth=jwt_auth)
 def payment_by_ref(request, ref_id: str):
-    pay = get_object_or_404(Payment.objects.select_related("event"), ref_id=ref_id)
+    pay = get_object_or_404(
+        Payment.objects.select_related("event"),
+        ref_id=ref_id,
+        user=request.auth,
+    )
     return _payment_detail_payload(request, pay)
 
 @payments_router.post("/coupon/check", response=CouponVerifyOut, auth=jwt_auth)

apps/payments/migrations/0005_payment_verification_attempts_and_more.py

@@ -0,0 +1,43 @@
+# Generated by Django 5.2.5 on 2026-09-30 18:36
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('payments', '0004_payment_idempotency_key_and_more'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='payment',
+            name='verification_attempts',
+            field=models.PositiveSmallIntegerField(default=0, editable=False),
+        ),
+        migrations.AddField(
+            model_name='payment',
+            name='verification_dispatch_expires_at',
+            field=models.DateTimeField(blank=True, editable=False, null=True),
+        ),
+        migrations.AddField(
+            model_name='payment',
+            name='verification_last_attempt_at',
+            field=models.DateTimeField(blank=True, editable=False, null=True),
+        ),
+        migrations.AddField(
+            model_name='payment',
+            name='verification_lease_until',
+            field=models.DateTimeField(blank=True, editable=False, null=True),
+        ),
+        migrations.AddField(
+            model_name='payment',
+            name='verification_manual_review_at',
+            field=models.DateTimeField(blank=True, editable=False, null=True),
+        ),
+        migrations.AddField(
+            model_name='payment',
+            name='verification_next_attempt_at',
+            field=models.DateTimeField(blank=True, editable=False, null=True),
+        ),
+    ]

apps/payments/migrations/0006_payment_refund_attempts_and_more.py

@@ -0,0 +1,43 @@
+# Generated by Django 5.2.5 on 2026-09-30 19:44
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('payments', '0005_payment_verification_attempts_and_more'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='payment',
+            name='refund_attempts',
+            field=models.PositiveSmallIntegerField(default=0, editable=False),
+        ),
+        migrations.AddField(
+            model_name='payment',
+            name='refund_last_attempt_at',
+            field=models.DateTimeField(blank=True, editable=False, null=True),
+        ),
+        migrations.AddField(
+            model_name='payment',
+            name='refund_last_error',
+            field=models.CharField(blank=True, default='', editable=False, max_length=255),
+        ),
+        migrations.AddField(
+            model_name='payment',
+            name='refund_next_attempt_at',
+            field=models.DateTimeField(blank=True, editable=False, null=True),
+        ),
+        migrations.AddField(
+            model_name='payment',
+            name='refund_reference',
+            field=models.CharField(blank=True, editable=False, max_length=64, null=True),
+        ),
+        migrations.AddField(
+            model_name='payment',
+            name='refund_status',
+            field=models.CharField(choices=[('none', 'No refund required'), ('pending', 'Refund pending'), ('succeeded', 'Refund completed'), ('manual_review', 'Refund needs review')], default='none', editable=False, max_length=20),
+        ),
+    ]

apps/payments/migrations/0007_payment_gateway_paid_at.py

@@ -0,0 +1,18 @@
+# Generated by Django 5.2.5 on 2026-10-01 04:42
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('payments', '0006_payment_refund_attempts_and_more'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='payment',
+            name='gateway_paid_at',
+            field=models.DateTimeField(blank=True, editable=False, null=True),
+        ),
+    ]

apps/payments/models.py

@@ -81,6 +81,12 @@ class Payment(BaseModel):
         FAILED = 3, "Failed"
         CANCELED = 4, "Canceled"
 
+    class RefundStatusChoices(models.TextChoices):
+        NONE = "none", "No refund required"
+        PENDING = "pending", "Refund pending"
+        SUCCEEDED = "succeeded", "Refund completed"
+        MANUAL_REVIEW = "manual_review", "Refund needs review"
+
     user  = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.PROTECT, related_name='payments', editable=False)
     event = models.ForeignKey(Event, on_delete=models.PROTECT, related_name='payments', editable=False)
 
@@ -104,6 +110,24 @@ class Payment(BaseModel):
     card_pan = models.CharField(max_length=32, null=True, blank=True, editable=False)
     card_hash = models.CharField(max_length=128, null=True, blank=True, editable=False)
     verified_at = models.DateTimeField(null=True, blank=True, editable=False)
+    gateway_paid_at = models.DateTimeField(null=True, blank=True, editable=False)
+    verification_attempts = models.PositiveSmallIntegerField(default=0, editable=False)
+    verification_last_attempt_at = models.DateTimeField(null=True, blank=True, editable=False)
+    verification_next_attempt_at = models.DateTimeField(null=True, blank=True, editable=False)
+    verification_lease_until = models.DateTimeField(null=True, blank=True, editable=False)
+    verification_dispatch_expires_at = models.DateTimeField(null=True, blank=True, editable=False)
+    verification_manual_review_at = models.DateTimeField(null=True, blank=True, editable=False)
+    refund_status = models.CharField(
+        max_length=20,
+        choices=RefundStatusChoices.choices,
+        default=RefundStatusChoices.NONE,
+        editable=False,
+    )
+    refund_attempts = models.PositiveSmallIntegerField(default=0, editable=False)
+    refund_last_attempt_at = models.DateTimeField(null=True, blank=True, editable=False)
+    refund_next_attempt_at = models.DateTimeField(null=True, blank=True, editable=False)
+    refund_reference = models.CharField(max_length=64, null=True, blank=True, editable=False)
+    refund_last_error = models.CharField(max_length=255, blank=True, default='', editable=False)
 
     class Meta:
         constraints = [
@@ -127,5 +151,24 @@ class Payment(BaseModel):
         """Human-readable label for the payment status."""
         return self.get_status_display()
 
+    @property
+    def verification_state(self):
+        """Server-owned verification state for callback and support screens."""
+        if self.status == self.OrderStatusChoices.PAID or self.verified_at is not None:
+            return "verified"
+        if self.status == self.OrderStatusChoices.FAILED:
+            return "failed"
+        if self.status == self.OrderStatusChoices.CANCELED:
+            return "canceled"
+        if self.verification_manual_review_at is not None or not self.authority:
+            return "manual_review"
+
+        now = timezone.now()
+        if self.verification_lease_until and self.verification_lease_until > now:
+            return "checking"
+        if self.verification_next_attempt_at:
+            return "retry_scheduled"
+        return "awaiting_verification"
+
     def __str__(self):
         return f"{self.user.email}:{self.event} - {self.get_status_display()}"

apps/payments/services.py

@@ -1,6 +1,10 @@
-"""Gateway operations whose responses must be interpreted conservatively."""
+"""Gateway operations and durable verification scheduling."""
+
+from datetime import timedelta
 
 from django.conf import settings
+from django.db import transaction
+from django.utils import timezone
 import requests
 
 
@@ -8,6 +12,14 @@ class PaymentVerificationUncertain(Exception):
     """The gateway response does not prove either payment success or failure."""
 
 
+class PaymentReversalUncertain(Exception):
+    """The gateway did not give a conclusive response to a reversal request."""
+
+
+class PaymentReversalRejected(Exception):
+    """The gateway definitively rejected the reversal and needs human review."""
+
+
 def request_payment_verification(payment):
     try:
         response = requests.post(
@@ -46,3 +58,184 @@ def request_payment_verification(payment):
         )
 
     return code, body["data"]
+
+
+def request_payment_reversal(payment):
+    """Reverse a paid transaction through ZarinPal's transaction reversal API."""
+    try:
+        response = requests.post(
+            settings.ZARINPAL_REVERSE_URL,
+            json={
+                "merchant_id": settings.ZARINPAL_MERCHANT_ID,
+                "authority": payment.authority,
+            },
+            headers={"accept": "application/json", "content-type": "application/json"},
+            timeout=15,
+        )
+        status_code = getattr(response, "status_code", 200)
+        if isinstance(status_code, int) and status_code >= 500:
+            raise PaymentReversalUncertain(
+                f"ZarinPal reversal returned HTTP {status_code}"
+            )
+        if isinstance(status_code, int) and status_code >= 400:
+            raise PaymentReversalRejected(
+                f"ZarinPal reversal was rejected with HTTP {status_code}"
+            )
+        body = response.json()
+    except (PaymentReversalUncertain, PaymentReversalRejected):
+        raise
+    except Exception as exc:
+        raise PaymentReversalUncertain("ZarinPal reversal request failed") from exc
+
+    if not isinstance(body, dict) or not isinstance(body.get("data"), dict):
+        if isinstance(body, dict) and isinstance(body.get("errors"), dict):
+            raise PaymentReversalRejected("ZarinPal rejected the reversal request")
+        raise PaymentReversalUncertain("ZarinPal returned an invalid reversal response")
+
+    code = body["data"].get("code")
+    try:
+        code = int(code)
+    except (TypeError, ValueError) as exc:
+        raise PaymentReversalUncertain("ZarinPal returned no reversal status code") from exc
+
+    if code != 100:
+        raise PaymentReversalRejected(f"ZarinPal rejected the reversal with code {code}")
+    return body["data"]
+
+
+def claim_payment_verification(
+    payment_id: int,
+    *,
+    lease_seconds: int = 120,
+    allow_terminal: bool = False,
+    allow_manual_review: bool = False,
+):
+    """Claim one bounded verification attempt using the database as the lock."""
+    from apps.payments.models import Payment
+
+    with transaction.atomic():
+        try:
+            payment = Payment.objects.select_for_update().get(pk=payment_id)
+        except Payment.DoesNotExist:
+            return None, False
+
+        if payment.status == Payment.OrderStatusChoices.PAID or (
+            payment.status in (
+                Payment.OrderStatusChoices.FAILED,
+                Payment.OrderStatusChoices.CANCELED,
+            )
+            and not allow_terminal
+        ):
+            return payment, False
+
+        now = timezone.now()
+        if payment.verification_manual_review_at is not None and not allow_manual_review:
+            return payment, False
+        if not payment.authority:
+            _mark_payment_manual_review(payment, now)
+            return payment, False
+        if payment.verification_lease_until and payment.verification_lease_until > now:
+            return payment, False
+
+        was_dispatched = bool(
+            payment.verification_dispatch_expires_at
+            and payment.verification_dispatch_expires_at > now
+        )
+        if (
+            payment.verification_next_attempt_at
+            and payment.verification_next_attempt_at > now
+            and not was_dispatched
+        ):
+            return payment, False
+
+        max_attempts = getattr(settings, "PAYMENT_VERIFICATION_MAX_ATTEMPTS", 6)
+        if payment.verification_attempts >= max_attempts and not allow_manual_review:
+            _mark_payment_manual_review(payment, now)
+            return payment, False
+
+        payment.verification_attempts += 1
+        payment.verification_last_attempt_at = now
+        payment.verification_next_attempt_at = None
+        payment.verification_lease_until = now + timedelta(seconds=lease_seconds)
+        payment.verification_dispatch_expires_at = None
+        payment.verification_manual_review_at = None
+        payment.save(update_fields=[
+            "verification_attempts",
+            "verification_last_attempt_at",
+            "verification_next_attempt_at",
+            "verification_lease_until",
+            "verification_dispatch_expires_at",
+            "verification_manual_review_at",
+        ])
+        return payment, True
+
+
+def schedule_payment_verification_retry(payment_id: int):
+    """Persist the next backoff step or stop at manual review after exhaustion."""
+    from apps.payments.models import Payment
+
+    with transaction.atomic():
+        try:
+            payment = Payment.objects.select_for_update().get(pk=payment_id)
+        except Payment.DoesNotExist:
+            return None
+
+        payment.verification_lease_until = None
+        payment.verification_dispatch_expires_at = None
+        if payment.status in (
+            Payment.OrderStatusChoices.PAID,
+            Payment.OrderStatusChoices.FAILED,
+            Payment.OrderStatusChoices.CANCELED,
+        ):
+            payment.verification_next_attempt_at = None
+            payment.verification_manual_review_at = None
+            payment.save(update_fields=[
+                "verification_lease_until",
+                "verification_dispatch_expires_at",
+                "verification_next_attempt_at",
+                "verification_manual_review_at",
+            ])
+            return None
+
+        max_attempts = getattr(settings, "PAYMENT_VERIFICATION_MAX_ATTEMPTS", 6)
+        if payment.verification_attempts >= max_attempts:
+            _mark_payment_manual_review(payment, timezone.now())
+            return None
+
+        attempt_index = max(payment.verification_attempts - 1, 0)
+        delay = min(60 * (2 ** attempt_index), 15 * 60)
+        payment.verification_next_attempt_at = timezone.now() + timedelta(seconds=delay)
+        payment.verification_manual_review_at = None
+        payment.save(update_fields=[
+            "verification_lease_until",
+            "verification_dispatch_expires_at",
+            "verification_next_attempt_at",
+            "verification_manual_review_at",
+        ])
+        return delay
+
+
+def mark_payment_manual_review(payment_id: int):
+    """Keep an unresolved payment pending and make support review durable."""
+    from apps.payments.models import Payment
+
+    with transaction.atomic():
+        try:
+            payment = Payment.objects.select_for_update().get(pk=payment_id)
+        except Payment.DoesNotExist:
+            return None
+        _mark_payment_manual_review(payment, timezone.now())
+        return payment
+
+
+def _mark_payment_manual_review(payment, now):
+    payment.verification_manual_review_at = payment.verification_manual_review_at or now
+    payment.verification_next_attempt_at = None
+    payment.verification_lease_until = None
+    payment.verification_dispatch_expires_at = None
+    payment.save(update_fields=[
+        "verification_manual_review_at",
+        "verification_next_attempt_at",
+        "verification_lease_until",
+        "verification_dispatch_expires_at",
+    ])

apps/payments/tasks.py

@@ -1,32 +1,63 @@
-"""Bounded retries for payment verification after an inconclusive callback."""
+"""Bounded payment verification and recovery for lost gateway callbacks."""
 
 import logging
+from datetime import timedelta
 
 from celery import shared_task
-from django.shortcuts import get_object_or_404
+from django.conf import settings
+from django.db import transaction
+from django.db.models import Q
+from django.utils import timezone
 
+from apps.events.models import Registration
 from apps.payments.models import Payment
-from apps.payments.services import PaymentVerificationUncertain, request_payment_verification
+from apps.payments.services import (
+    PaymentReversalRejected,
+    PaymentReversalUncertain,
+    PaymentVerificationUncertain,
+    claim_payment_verification,
+    request_payment_verification,
+    request_payment_reversal,
+    schedule_payment_verification_retry,
+)
 
 logger = logging.getLogger(__name__)
 
 
-@shared_task(bind=True, max_retries=5, name="apps.payments.reconcile_payment")
+def _status_result(payment):
-def reconcile_payment(self, payment_id: int):
+    return {
-    payment = get_object_or_404(
+        Payment.OrderStatusChoices.PAID: "paid",
-        Payment.objects.select_related("event", "user"),
+        Payment.OrderStatusChoices.FAILED: "failed",
-        pk=payment_id,
+        Payment.OrderStatusChoices.CANCELED: "canceled",
-    )
+    }.get(payment.status)
-    if payment.status in (Payment.OrderStatusChoices.PAID, Payment.OrderStatusChoices.FAILED):
-        return payment.get_status_display().lower()
-    if not payment.authority:
-        logger.error(
-            "Payment %s remains pending without a gateway authority; manual review is required",
-            payment.id,
-        )
-        return "pending_manual_review"
 
-    # Imported at task runtime to avoid a view/task import cycle.
+
+def _queue_retry(payment_id: int, countdown: int):
+    try:
+        reconcile_payment.apply_async(args=(payment_id,), countdown=countdown)
+    except Exception:
+        logger.exception(
+            "Unable to queue payment verification for payment %s; the recovery sweep will retry it",
+            payment_id,
+        )
+
+
+@shared_task(name="apps.payments.reconcile_payment")
+def reconcile_payment(payment_id: int):
+    payment, claimed = claim_payment_verification(payment_id)
+    if payment is None:
+        return "not_found"
+    if not claimed:
+        terminal_result = _status_result(payment)
+        if terminal_result:
+            return terminal_result
+        if payment.verification_manual_review_at is not None or not payment.authority:
+            return "pending_manual_review"
+        if payment.verification_lease_until and payment.verification_lease_until > timezone.now():
+            return "verification_in_progress"
+        return "not_due"
+
+    # Imported here to avoid a view/task import cycle.
     from apps.payments.api.views import (
         _mark_payment_paid,
         _mark_payment_pending,
@@ -38,24 +69,37 @@ def reconcile_payment(self, payment_id: int):
         code, data = request_payment_verification(payment)
     except PaymentVerificationUncertain as exc:
         _mark_payment_pending(payment.id)
-        if self.request.retries >= self.max_retries:
+        delay = schedule_payment_verification_retry(payment.id)
+        if delay is None:
             logger.error(
-                "Payment %s verification remains uncertain after bounded retries; manual review is required",
+                "Payment %s remains pending after exhausting verification attempts; manual review is required",
                 payment.id,
                 exc_info=exc,
             )
             return "pending_manual_review"
-        countdown = min(60 * (2 ** self.request.retries), 15 * 60)
+        _queue_retry(payment.id, delay)
-        raise self.retry(exc=exc, countdown=countdown)
+        return "retry_scheduled"
 
     if code in (100, 101):
         payment, newly_verified = _mark_payment_paid(payment.id, data)
         if newly_verified:
+            refund_pending = payment.refund_status in (
+                Payment.RefundStatusChoices.PENDING,
+                Payment.RefundStatusChoices.MANUAL_REVIEW,
+            )
             _notify_payment_status(
                 payment,
-                title=f"پرداخت رویداد «{payment.event.title}» تأیید شد",
+                title=(
-                message="پرداخت شما با موفقیت ثبت شد و ثبت‌نام رویداد تکمیل شده است.",
+                    f"پرداخت رویداد «{payment.event.title}» تأیید شد؛ بازگشت وجه در حال پیگیری است"
-                level="success",
+                    if refund_pending
+                    else f"پرداخت رویداد «{payment.event.title}» تأیید شد"
+                ),
+                message=(
+                    "ثبت‌نام لغو شده است. بازگشت وجه به‌صورت خودکار پیگیری می‌شود؛ اگر نتیجه روشن نشود، پشتیبانی آن را بررسی می‌کند."
+                    if refund_pending
+                    else "پرداخت شما با موفقیت ثبت شد و ثبت‌نام رویداد تکمیل شده است."
+                ),
+                level="warning" if refund_pending else "success",
             )
         return "paid"
 
@@ -71,3 +115,204 @@ def reconcile_payment(self, payment_id: int):
             level="error",
         )
     return result
+
+
+@shared_task(name="apps.payments.sweep_stale_payment_verifications")
+def sweep_stale_payment_verifications():
+    """Queue due old attempts so lost callbacks and broker failures recover safely."""
+    now = timezone.now()
+    grace_seconds = max(
+        0,
+        getattr(settings, "PAYMENT_VERIFICATION_GRACE_SECONDS", 1800),
+    )
+    cutoff = now - timedelta(seconds=grace_seconds)
+    max_attempts = getattr(settings, "PAYMENT_VERIFICATION_MAX_ATTEMPTS", 6)
+    dispatch_lease_seconds = max(
+        60,
+        getattr(settings, "PAYMENT_VERIFICATION_DISPATCH_LEASE_SECONDS", 900),
+    )
+
+    candidates = (
+        Payment.objects.filter(
+            status__in=[
+                Payment.OrderStatusChoices.INIT,
+                Payment.OrderStatusChoices.PENDING,
+            ],
+            authority__isnull=False,
+            verification_attempts__lt=max_attempts,
+            verification_manual_review_at__isnull=True,
+        )
+        .filter(
+            Q(created_at__lte=cutoff)
+            | Q(registration__cancellation_reason__in=[
+                "checkout_expired", "user_cancelled", "event_cancelled",
+            ])
+        )
+        .filter(Q(verification_next_attempt_at__isnull=True) | Q(verification_next_attempt_at__lte=now))
+        .filter(Q(verification_lease_until__isnull=True) | Q(verification_lease_until__lte=now))
+        .filter(
+            Q(verification_dispatch_expires_at__isnull=True)
+            | Q(verification_dispatch_expires_at__lte=now)
+        )
+        .order_by("created_at", "pk")
+        .values_list("pk", flat=True)[:100]
+    )
+
+    scheduled = 0
+    for payment_id in candidates:
+        with transaction.atomic():
+            payment = Payment.objects.select_for_update().filter(pk=payment_id).first()
+            if payment is None:
+                continue
+            canceled_checkout = bool(
+                payment.registration_id
+                and Registration.objects.filter(
+                    pk=payment.registration_id,
+                    cancellation_reason__in=[
+                        Registration.CancellationReasonChoices.CHECKOUT_EXPIRED,
+                        Registration.CancellationReasonChoices.USER_CANCELLED,
+                        Registration.CancellationReasonChoices.EVENT_CANCELLED,
+                    ],
+                ).exists()
+            )
+            if (
+                payment.status not in (
+                    Payment.OrderStatusChoices.INIT,
+                    Payment.OrderStatusChoices.PENDING,
+                )
+                or not payment.authority
+                or (payment.created_at > cutoff and not canceled_checkout)
+                or payment.verification_attempts >= max_attempts
+                or payment.verification_manual_review_at is not None
+                or (payment.verification_lease_until and payment.verification_lease_until > now)
+                or (
+                    payment.verification_next_attempt_at
+                    and payment.verification_next_attempt_at > now
+                )
+                or (
+                    payment.verification_dispatch_expires_at
+                    and payment.verification_dispatch_expires_at > now
+                )
+            ):
+                continue
+
+            dispatch_expires_at = now + timedelta(seconds=dispatch_lease_seconds)
+            payment.verification_dispatch_expires_at = dispatch_expires_at
+            payment.save(update_fields=["verification_dispatch_expires_at"])
+            try:
+                reconcile_payment.apply_async(args=(payment.id,))
+            except Exception:
+                Payment.objects.filter(
+                    pk=payment.id,
+                    verification_dispatch_expires_at=dispatch_expires_at,
+                ).update(verification_dispatch_expires_at=None)
+                logger.exception(
+                    "Unable to dispatch stale payment %s for verification",
+                    payment.id,
+                )
+                continue
+            scheduled += 1
+
+    return scheduled
+
+
+@shared_task(name="apps.payments.refund_payment")
+def refund_payment(payment_id: int):
+    """Attempt a bounded ZarinPal reversal; surface unresolved refunds to admins."""
+    now = timezone.now()
+    lease = timedelta(seconds=max(60, getattr(settings, "PAYMENT_REFUND_LEASE_SECONDS", 120)))
+    with transaction.atomic():
+        payment = Payment.objects.select_for_update().filter(pk=payment_id).first()
+        if payment is None:
+            return "not_found"
+        if (
+            payment.status != Payment.OrderStatusChoices.PAID
+            or payment.refund_status != Payment.RefundStatusChoices.PENDING
+        ):
+            return payment.refund_status
+        if payment.refund_next_attempt_at and payment.refund_next_attempt_at > now:
+            return "not_due"
+        if not payment.authority:
+            payment.refund_status = Payment.RefundStatusChoices.MANUAL_REVIEW
+            payment.refund_last_error = "No gateway authority is available for reversal."
+            payment.refund_next_attempt_at = None
+            payment.save(update_fields=[
+                "refund_status", "refund_last_error", "refund_next_attempt_at",
+            ])
+            return "manual_review"
+
+        max_attempts = max(1, getattr(settings, "PAYMENT_REFUND_MAX_ATTEMPTS", 3))
+        if payment.refund_attempts >= max_attempts:
+            payment.refund_status = Payment.RefundStatusChoices.MANUAL_REVIEW
+            payment.refund_next_attempt_at = None
+            payment.save(update_fields=["refund_status", "refund_next_attempt_at"])
+            return "manual_review"
+
+        payment.refund_attempts += 1
+        payment.refund_last_attempt_at = now
+        # Duplicate task deliveries cannot issue concurrent reversals. If a
+        # worker dies after the external request, the sweep retries at lease end.
+        payment.refund_next_attempt_at = now + lease
+        payment.save(update_fields=[
+            "refund_attempts", "refund_last_attempt_at", "refund_next_attempt_at",
+        ])
+
+    try:
+        data = request_payment_reversal(payment)
+    except PaymentReversalRejected as exc:
+        Payment.objects.filter(pk=payment_id).update(
+            refund_status=Payment.RefundStatusChoices.MANUAL_REVIEW,
+            refund_last_error=str(exc)[:255],
+            refund_next_attempt_at=None,
+        )
+        return "manual_review"
+    except PaymentReversalUncertain as exc:
+        with transaction.atomic():
+            current = Payment.objects.select_for_update().get(pk=payment_id)
+            current.refund_last_error = str(exc)[:255]
+            if current.refund_attempts >= max(1, getattr(settings, "PAYMENT_REFUND_MAX_ATTEMPTS", 3)):
+                current.refund_status = Payment.RefundStatusChoices.MANUAL_REVIEW
+                current.refund_next_attempt_at = None
+                result = "manual_review"
+            else:
+                delay = min(60 * (2 ** (current.refund_attempts - 1)), 15 * 60)
+                current.refund_next_attempt_at = timezone.now() + timedelta(seconds=delay)
+                result = "retry_scheduled"
+            current.save(update_fields=[
+                "refund_status", "refund_last_error", "refund_next_attempt_at",
+            ])
+        if result == "retry_scheduled":
+            try:
+                refund_payment.apply_async(args=(payment_id,), countdown=delay)
+            except Exception:
+                logger.exception("Unable to queue refund retry for payment %s", payment_id)
+        return result
+
+    Payment.objects.filter(pk=payment_id).update(
+        refund_status=Payment.RefundStatusChoices.SUCCEEDED,
+        refund_reference=str(data.get("ref_id") or data.get("reference") or "")[:64] or None,
+        refund_last_error="",
+        refund_next_attempt_at=None,
+    )
+    return "refunded"
+
+
+@shared_task(name="apps.payments.sweep_pending_refunds")
+def sweep_pending_refunds():
+    """Recover refund work when an immediate Celery dispatch is lost."""
+    now = timezone.now()
+    due_ids = Payment.objects.filter(
+        status=Payment.OrderStatusChoices.PAID,
+        refund_status=Payment.RefundStatusChoices.PENDING,
+    ).filter(
+        Q(refund_next_attempt_at__isnull=True) | Q(refund_next_attempt_at__lte=now)
+    ).order_by("refund_last_attempt_at", "pk").values_list("pk", flat=True)[:100]
+
+    scheduled = 0
+    for payment_id in due_ids:
+        try:
+            refund_payment.apply_async(args=(payment_id,))
+            scheduled += 1
+        except Exception:
+            logger.exception("Unable to dispatch pending refund for payment %s", payment_id)
+    return scheduled

apps/payments/tests/integration/test_payment_admin.py

@@ -86,7 +86,8 @@ def test_payment_callback_verification_failures_notify_once(client, user_factory
     else:
         gateway.return_value.json.return_value = gateway_result
     response = client.get("/api/payments/callback", {"Authority": "AUTH-FAIL", "Status": "OK"})
-    assert response.status_code == 302 and "status=pending" in response.url
+    assert response.status_code == 302
+    assert f"/events/{event.slug}/registration?registration_id={registration.ticket_id}" in response.url
     payment.refresh_from_db()
     registration.refresh_from_db()
     assert payment.status == Payment.OrderStatusChoices.PENDING

apps/payments/tests/integration/test_payment_reconciliation.py

@@ -1,4 +1,7 @@
+from datetime import timedelta
+
 import pytest
+from django.utils import timezone
 
 from apps.events.models import Registration
 from apps.payments.models import Payment
@@ -39,13 +42,16 @@ def test_reconciliation_retry_confirms_payment_after_transient_timeout(
         mocker.Mock(**{"json.return_value": {"data": {"code": 100, "ref_id": "REF-RETRY"}}}),
     ]
     notify = mocker.patch("apps.payments.api.views._notify_payment_status")
+    enqueue = mocker.patch("apps.payments.tasks.reconcile_payment.apply_async")
 
-    retry = mocker.patch.object(reconcile_payment, "retry", side_effect=RuntimeError("retry scheduled"))
+    assert reconcile_payment.run(payment.id) == "retry_scheduled"
-    with pytest.raises(RuntimeError, match="retry scheduled"):
+    payment.refresh_from_db()
-        reconcile_payment.run(payment.id)
+    assert payment.verification_attempts == 1
-
+    assert payment.verification_next_attempt_at is not None
-    retry.assert_called_once()
+    enqueue.assert_called_once_with(args=(payment.id,), countdown=60)
-    assert retry.call_args.kwargs["countdown"] == 60
+    Payment.objects.filter(pk=payment.pk).update(
+        verification_next_attempt_at=timezone.now() - timedelta(seconds=1)
+    )
     gateway.side_effect = [
         mocker.Mock(**{"json.return_value": {"data": {"code": 100, "ref_id": "REF-RETRY"}}})
     ]
@@ -57,6 +63,8 @@ def test_reconciliation_retry_confirms_payment_after_transient_timeout(
     assert gateway.call_count == 2
     assert payment.status == Payment.OrderStatusChoices.PAID
     assert payment.ref_id == "REF-RETRY"
+    assert payment.verification_attempts == 2
+    assert payment.verification_manual_review_at is None
     assert registration.status == Registration.StatusChoices.CONFIRMED
     notify.assert_called_once()
 
@@ -67,27 +75,27 @@ def test_reconciliation_exhaustion_leaves_payment_pending_for_review(
     payment, registration = _pending_payment(user_factory, event_factory)
     settings.ZARINPAL_MERCHANT_ID = "test"
     settings.ZARINPAL_VERIFY_URL = "https://gateway.example/verify"
+    settings.PAYMENT_VERIFICATION_MAX_ATTEMPTS = 6
     gateway = mocker.patch("apps.payments.services.requests.post", side_effect=RuntimeError("gateway offline"))
     notify = mocker.patch("apps.payments.api.views._notify_payment_status")
-    retry = mocker.patch.object(reconcile_payment, "retry", side_effect=RuntimeError("retry scheduled"))
+    mocker.patch("apps.payments.tasks.reconcile_payment.apply_async")
 
-    for retry_number in range(reconcile_payment.max_retries + 1):
+    for attempt_number in range(settings.PAYMENT_VERIFICATION_MAX_ATTEMPTS):
-        reconcile_payment.push_request(retries=retry_number)
+        Payment.objects.filter(pk=payment.pk).update(
-        try:
+            verification_next_attempt_at=timezone.now() - timedelta(seconds=1)
-            if retry_number < reconcile_payment.max_retries:
+        )
-                with pytest.raises(RuntimeError, match="retry scheduled"):
+        result = reconcile_payment.run(payment.id)
-                    reconcile_payment.run(payment.id)
+        if attempt_number < settings.PAYMENT_VERIFICATION_MAX_ATTEMPTS - 1:
-            else:
+            assert result == "retry_scheduled"
-                result = reconcile_payment.run(payment.id)
-        finally:
-            reconcile_payment.pop_request()
 
     payment.refresh_from_db()
     registration.refresh_from_db()
     assert result == "pending_manual_review"
-    assert gateway.call_count == reconcile_payment.max_retries + 1
+    assert gateway.call_count == settings.PAYMENT_VERIFICATION_MAX_ATTEMPTS
-    assert [call.kwargs["countdown"] for call in retry.call_args_list] == [60, 120, 240, 480, 900]
+    assert payment.verification_attempts == settings.PAYMENT_VERIFICATION_MAX_ATTEMPTS
     assert payment.status == Payment.OrderStatusChoices.PENDING
+    assert payment.verification_manual_review_at is not None
+    assert payment.verification_next_attempt_at is None
     assert registration.status == Registration.StatusChoices.PENDING
     notify.assert_not_called()
 
@@ -137,3 +145,162 @@ def test_failed_attempt_does_not_cancel_registration_used_by_another_active_paym
     registration.refresh_from_db()
     assert payment.status == Payment.OrderStatusChoices.FAILED
     assert registration.status == Registration.StatusChoices.PENDING
+
+
+def _expired_checkout_payment(user_factory, event_factory):
+    now = timezone.now()
+    user = user_factory()
+    event = event_factory(price=25000, capacity=2)
+    registration = Registration.objects.create(
+        event=event,
+        user=user,
+        status=Registration.StatusChoices.CANCELLED,
+        checkout_started_at=now - timedelta(minutes=20),
+        checkout_expires_at=now - timedelta(minutes=5),
+        cancellation_reason=Registration.CancellationReasonChoices.CHECKOUT_EXPIRED,
+        final_price=25000,
+    )
+    payment = Payment.objects.create(
+        user=user,
+        event=event,
+        registration=registration,
+        base_amount=25000,
+        amount=25000,
+        authority=f"AUTH-LATE-{user.pk}",
+        status=Payment.OrderStatusChoices.PENDING,
+    )
+    return payment, registration
+
+
+def test_late_success_without_provider_payment_time_keeps_registration_cancelled(
+    user_factory, event_factory, mocker
+):
+    from apps.payments.api.views import _mark_payment_paid
+
+    payment, registration = _expired_checkout_payment(user_factory, event_factory)
+    mocker.patch("apps.payments.tasks.refund_payment.apply_async")
+
+    payment, newly_verified = _mark_payment_paid(payment.id, {"ref_id": "LATE-REF"})
+
+    registration.refresh_from_db()
+    assert newly_verified is True
+    assert payment.status == Payment.OrderStatusChoices.PAID
+    assert payment.refund_status == Payment.RefundStatusChoices.PENDING
+    assert registration.status == Registration.StatusChoices.CANCELLED
+
+
+def test_late_success_with_proven_pre_expiry_payment_and_available_seat_is_honored(
+    user_factory, event_factory
+):
+    from apps.payments.api.views import _mark_payment_paid
+
+    payment, registration = _expired_checkout_payment(user_factory, event_factory)
+    paid_at = (registration.checkout_expires_at - timedelta(seconds=1)).isoformat()
+
+    payment, _ = _mark_payment_paid(payment.id, {"ref_id": "ONTIME-REF", "paid_at": paid_at})
+
+    registration.refresh_from_db()
+    assert registration.status == Registration.StatusChoices.CONFIRMED
+    assert payment.refund_status == Payment.RefundStatusChoices.NONE
+
+
+def test_late_success_with_proven_pre_expiry_time_is_refunded_when_capacity_is_full(
+    user_factory, event_factory
+):
+    from apps.payments.api.views import _mark_payment_paid
+
+    payment, registration = _expired_checkout_payment(user_factory, event_factory)
+    payment.event.capacity = 1
+    payment.event.save(update_fields=["capacity"])
+    other_user = user_factory()
+    Registration.objects.create(
+        event=payment.event,
+        user=other_user,
+        status=Registration.StatusChoices.CONFIRMED,
+    )
+    paid_at = (registration.checkout_expires_at - timedelta(seconds=1)).isoformat()
+
+    payment, _ = _mark_payment_paid(payment.id, {"ref_id": "FULL-REF", "paid_at": paid_at})
+
+    registration.refresh_from_db()
+    assert registration.status == Registration.StatusChoices.CANCELLED
+    assert payment.refund_status == Payment.RefundStatusChoices.PENDING
+
+
+@pytest.mark.parametrize(
+    ("reason", "cancel_event"),
+    [
+        (Registration.CancellationReasonChoices.USER_CANCELLED, False),
+        (Registration.CancellationReasonChoices.EVENT_CANCELLED, True),
+    ],
+)
+def test_late_success_after_user_or_event_cancellation_is_refunded(
+    user_factory, event_factory, mocker, reason, cancel_event
+):
+    from apps.payments.api.views import _mark_payment_paid
+
+    payment, registration = _expired_checkout_payment(user_factory, event_factory)
+    registration.cancellation_reason = reason
+    registration.save(update_fields=["cancellation_reason"])
+    if cancel_event:
+        payment.event.status = payment.event.StatusChoices.CANCELLED
+        payment.event.save(update_fields=["status"])
+    mocker.patch("apps.payments.tasks.refund_payment.apply_async")
+    paid_at = (registration.checkout_expires_at - timedelta(seconds=1)).isoformat()
+
+    payment, _ = _mark_payment_paid(payment.id, {"ref_id": "CANCELLED-REF", "paid_at": paid_at})
+
+    registration.refresh_from_db()
+    assert registration.status == Registration.StatusChoices.CANCELLED
+    assert registration.cancellation_reason == reason
+    assert payment.refund_status == Payment.RefundStatusChoices.PENDING
+
+
+def test_late_success_refund_task_persists_provider_reversal(mocker, user_factory, event_factory):
+    from apps.payments.tasks import refund_payment
+
+    payment, registration = _expired_checkout_payment(user_factory, event_factory)
+    Payment.objects.filter(pk=payment.pk).update(
+        status=Payment.OrderStatusChoices.PAID,
+        refund_status=Payment.RefundStatusChoices.PENDING,
+    )
+    reverse = mocker.patch(
+        "apps.payments.tasks.request_payment_reversal",
+        return_value={"code": 100, "ref_id": "REVERSAL-1"},
+    )
+
+    result = refund_payment.run(payment.id)
+
+    payment.refresh_from_db()
+    assert result == "refunded"
+    assert payment.refund_status == Payment.RefundStatusChoices.SUCCEEDED
+    assert payment.refund_reference == "REVERSAL-1"
+    assert payment.refund_attempts == 1
+    reverse.assert_called_once()
+
+
+def test_uncertain_reversal_retries_then_keeps_admin_review_state(mocker, user_factory, event_factory, settings):
+    from apps.payments.services import PaymentReversalUncertain
+    from apps.payments.tasks import refund_payment
+
+    payment, _ = _expired_checkout_payment(user_factory, event_factory)
+    Payment.objects.filter(pk=payment.pk).update(
+        status=Payment.OrderStatusChoices.PAID,
+        refund_status=Payment.RefundStatusChoices.PENDING,
+        refund_attempts=2,
+    )
+    settings.PAYMENT_REFUND_MAX_ATTEMPTS = 3
+    mocker.patch(
+        "apps.payments.tasks.request_payment_reversal",
+        side_effect=PaymentReversalUncertain("gateway timed out"),
+    )
+    enqueue = mocker.patch("apps.payments.tasks.refund_payment.apply_async")
+
+    result = refund_payment.run(payment.id)
+
+    payment.refresh_from_db()
+    assert result == "manual_review"
+    assert payment.refund_status == Payment.RefundStatusChoices.MANUAL_REVIEW
+    assert payment.refund_attempts == 3
+    assert payment.refund_next_attempt_at is None
+    enqueue.assert_not_called()

apps/payments/tests/integration/test_payment_recovery_sweep.py

@@ -0,0 +1,82 @@
+from datetime import timedelta
+
+import pytest
+from django.utils import timezone
+
+from apps.payments.models import Payment
+from apps.payments.tasks import sweep_stale_payment_verifications
+
+pytestmark = [pytest.mark.integration, pytest.mark.django_db]
+
+
+def test_sweep_schedules_only_old_unresolved_payments_and_deduplicates_dispatch(
+    user_factory, event_factory, mocker, settings
+):
+    settings.PAYMENT_VERIFICATION_GRACE_SECONDS = 1800
+    user = user_factory()
+    event = event_factory(price=25000)
+    old_payment = Payment.objects.create(
+        user=user,
+        event=event,
+        base_amount=25000,
+        amount=25000,
+        authority="AUTH-RECOVERY-OLD",
+        status=Payment.OrderStatusChoices.PENDING,
+    )
+    recent_payment = Payment.objects.create(
+        user=user,
+        event=event,
+        base_amount=25000,
+        amount=25000,
+        authority="AUTH-RECOVERY-NEW",
+        status=Payment.OrderStatusChoices.PENDING,
+    )
+    Payment.objects.filter(pk=old_payment.pk).update(
+        created_at=timezone.now() - timedelta(seconds=1801)
+    )
+    enqueue = mocker.patch("apps.payments.tasks.reconcile_payment.apply_async")
+
+    scheduled = sweep_stale_payment_verifications.run()
+
+    old_payment.refresh_from_db()
+    recent_payment.refresh_from_db()
+    assert scheduled == 1
+    enqueue.assert_called_once_with(args=(old_payment.pk,))
+    assert old_payment.verification_dispatch_expires_at is not None
+    assert old_payment.verification_dispatch_expires_at > timezone.now()
+    assert recent_payment.verification_next_attempt_at is None
+
+    assert sweep_stale_payment_verifications.run() == 0
+    enqueue.assert_called_once()
+
+
+def test_sweep_does_not_restart_exhausted_or_terminal_attempts(
+    user_factory, event_factory, mocker, settings
+):
+    settings.PAYMENT_VERIFICATION_GRACE_SECONDS = 60
+    settings.PAYMENT_VERIFICATION_MAX_ATTEMPTS = 3
+    user = user_factory()
+    event = event_factory(price=25000)
+    payments = [
+        Payment.objects.create(
+            user=user,
+            event=event,
+            base_amount=25000,
+            amount=25000,
+            authority=f"AUTH-RECOVERY-{status}-{index}",
+            status=status,
+            verification_attempts=3,
+        )
+        for index, status in enumerate(
+            [Payment.OrderStatusChoices.PENDING, Payment.OrderStatusChoices.FAILED]
+        )
+    ]
+    Payment.objects.filter(pk__in=[payment.pk for payment in payments]).update(
+        created_at=timezone.now() - timedelta(minutes=5)
+    )
+    enqueue = mocker.patch("apps.payments.tasks.reconcile_payment.apply_async")
+
+    scheduled = sweep_stale_payment_verifications.run()
+
+    assert scheduled == 0
+    enqueue.assert_not_called()

apps/payments/tests/integration/test_payments.py

@@ -168,7 +168,8 @@ class TestPaymentsAPIIntegrationTests:
         response = self.client.get('/api/payments/callback', {'Authority': 'AUTH123', 'Status': 'OK'})
         payment.refresh_from_db()
         assert payment.status == Payment.OrderStatusChoices.PAID
-        assert 'status=success' in response.url
+        assert f'/events/{self.event.slug}/registration?payment_id={payment.id}' in response.url
+        assert 'status=' not in response.url
 
     def test_callback_failure_redirects_failed(self, mocker):
         mock_post = mocker.patch('apps.payments.api.views.requests.post')
@@ -179,11 +180,21 @@ class TestPaymentsAPIIntegrationTests:
         response = self.client.get('/api/payments/callback', {'Authority': 'AUTH456', 'Status': 'OK'})
         payment.refresh_from_db()
         assert payment.status == Payment.OrderStatusChoices.PAID
-        assert 'status=success' in response.url
+        assert f'/events/{self.event.slug}/registration?payment_id={payment.id}' in response.url
 
-    def test_callback_missing_authority_returns_error(self):
+    def test_callback_missing_authority_redirects_to_safe_unknown_result(self):
         response = self.client.get('/api/payments/callback', {'Status': 'OK'})
-        assert response.status_code == 400
+        assert response.status_code == 302
+        assert '/events?payment_callback=unmatched' in response.url
+
+    def test_callback_unknown_authority_redirects_to_safe_unknown_result(self):
+        response = self.client.get(
+            '/api/payments/callback',
+            {'Authority': 'AUTH-UNKNOWN', 'Status': 'OK'},
+        )
+        assert response.status_code == 302
+        assert '/events?payment_callback=unmatched' in response.url
+        assert 'AUTH-UNKNOWN' not in response.url
 
     def test_callback_not_ok_is_verified_before_being_canceled(self, mocker):
         payment = Payment.objects.create(user=self.user, event=self.event, base_amount=self.event.price, amount=self.event.price, status=Payment.OrderStatusChoices.PENDING, authority='AUTH789')
@@ -191,8 +202,8 @@ class TestPaymentsAPIIntegrationTests:
         gateway.return_value.json.return_value = {'data': {'code': -51}}
         response = self.client.get('/api/payments/callback', {'Authority': 'AUTH789', 'Status': 'NOK'})
         payment.refresh_from_db()
-        assert payment.status == Payment.OrderStatusChoices.FAILED
+        assert payment.status == Payment.OrderStatusChoices.CANCELED
-        assert 'status=failed' in response.url
+        assert f'/events/{self.event.slug}/registration?payment_id={payment.id}' in response.url
 
     def test_late_canceled_callback_does_not_overwrite_verified_payment(self, mocker):
         registration = Registration.objects.create(
@@ -229,8 +240,9 @@ class TestPaymentsAPIIntegrationTests:
         assert payment.status == Payment.OrderStatusChoices.PAID
         assert payment.verified_at is not None
         assert registration.status == Registration.StatusChoices.CONFIRMED
-        assert 'status=success' in success_response.url
+        expected_return = f'/events/{self.event.slug}/registration?registration_id={registration.ticket_id}'
-        assert 'status=success' in late_failure_response.url
+        assert expected_return in success_response.url
+        assert expected_return in late_failure_response.url
 
     def test_create_payment_gateway_timeout_stays_pending(self, mocker):
         mocker.patch('apps.payments.api.views.requests.post', side_effect=RuntimeError('down'))
@@ -249,8 +261,7 @@ class TestPaymentsAPIIntegrationTests:
 
         payment.refresh_from_db()
         assert response.status_code == 302
-        assert 'status=pending' in response.url
+        assert f'/events/{self.event.slug}/registration?payment_id={payment.id}' in response.url
-        assert f'payment_id={payment.id}' in response.url
         assert payment.status == Payment.OrderStatusChoices.PENDING
         reconcile.assert_called_once_with(args=(payment.id,), countdown=60)
         notify.assert_not_called()
@@ -261,12 +272,45 @@ class TestPaymentsAPIIntegrationTests:
         assert own.status_code == 200
         assert own.json()['payment_id'] == payment.id
         assert own.json()['status'] == 'pending'
+        assert own.json()['verification_state'] == 'awaiting_verification'
+        assert own.json()['verification_attempts'] == 0
+        assert own.json()['last_verification_at'] is None
+        assert own.json()['manual_review_at'] is None
 
         other = User.objects.create_user(username='other_payment_owner', email='other-payment@example.com', mobile='09123456780', password=self.password)
         other_token = create_jwt_token(other)
         forbidden = self.client.get(f'/api/payments/status/{payment.id}', HTTP_AUTHORIZATION=f'Bearer {other_token}')
         assert forbidden.status_code == 404
 
+    def test_payment_reference_lookup_requires_authentication_and_is_user_scoped(self):
+        payment = Payment.objects.create(
+            user=self.user,
+            event=self.event,
+            base_amount=self.event.price,
+            amount=self.event.price,
+            status=Payment.OrderStatusChoices.PAID,
+            ref_id="OWNER-ONLY-REF",
+        )
+
+        unauthenticated = self.client.get("/api/payments/by-ref/OWNER-ONLY-REF")
+        owned = self.client.get("/api/payments/by-ref/OWNER-ONLY-REF", **self._headers())
+        other = User.objects.create_user(
+            username="other_ref_owner",
+            email="other-ref-owner@example.com",
+            mobile="09123456781",
+            password=self.password,
+        )
+        other_token = create_jwt_token(other)
+        forbidden = self.client.get(
+            "/api/payments/by-ref/OWNER-ONLY-REF",
+            HTTP_AUTHORIZATION=f"Bearer {other_token}",
+        )
+
+        assert unauthenticated.status_code == 401
+        assert owned.status_code == 200
+        assert owned.json()["payment_id"] == payment.id
+        assert forbidden.status_code == 404
+
     def test_create_payment_when_already_paid(self):
         Payment.objects.create(user=self.user, event=self.event, base_amount=self.event.price, amount=self.event.price, status=Payment.OrderStatusChoices.PAID)
         response = self.client.post('/api/payments/create', data=json.dumps({'event_id': self.event.id, 'description': 'Duplicate'}), content_type='application/json', **self._headers())
@@ -341,10 +385,12 @@ def test_my_payments_are_user_scoped_and_omit_gateway_identifiers(client, user_f
     payload = response.json()
     assert len(payload) == 1
     assert payload[0]["event"]["title"] == own_event.title
+    assert payload[0]["event"]["id"] == own_event.id
     assert payload[0]["amount"] == 100000
     assert payload[0]["discount_amount"] == 20000
     assert payload[0]["status"] == "paid"
-    assert set(payload[0]) == {"event", "base_amount", "discount_amount", "amount", "status", "created_at", "paid_at"}
+    assert set(payload[0]) == {"payment_id", "event", "base_amount", "discount_amount", "amount", "status", "refund_status", "created_at", "paid_at"}
+    assert payload[0]["payment_id"] == Payment.objects.get(user=current_user, event=own_event).id
     assert "internal-authority-owner" not in response.content.decode()
     assert "internal-reference-owner" not in response.content.decode()
     assert "internal-card-hash" not in response.content.decode()

config/services/celery.py

@@ -38,6 +38,21 @@ app.conf.beat_schedule = {
         'schedule': crontab(hour=2, minute=0),
         'description': 'Runs daily at 02:00 UTC to cleanup notification retention.',
     },
+    'sweep-stale-payment-verifications': {
+        'task': 'apps.payments.sweep_stale_payment_verifications',
+        'schedule': crontab(minute='*/5'),
+        'description': 'Recovers old unresolved payment attempts with bounded gateway verification.',
+    },
+    'expire-stale-registration-checkouts': {
+        'task': 'apps.events.expire_stale_registration_checkouts',
+        'schedule': crontab(minute='*'),
+        'description': 'Releases seats from paid checkouts after their 15-minute window.',
+    },
+    'sweep-pending-refunds': {
+        'task': 'apps.payments.sweep_pending_refunds',
+        'schedule': crontab(minute='*/5'),
+        'description': 'Recovers pending transaction reversals and exposes exhausted attempts for admin review.',
+    },
 }
 
 CELERY_TASK_SOFT_TIME_LIMIT = 20

config/services/zarinpal.py

@@ -6,5 +6,6 @@ ZARINPAL_USE_SANDBOX = config('ZARINPAL_USE_SANDBOX', default=False, cast=bool)
 ZARINPAL_API_BASE = "https://sandbox.zarinpal.com" if ZARINPAL_USE_SANDBOX else "https://payment.zarinpal.com"
 ZARINPAL_REQUEST_URL = f"{ZARINPAL_API_BASE}/pg/v4/payment/request.json"
 ZARINPAL_VERIFY_URL  = f"{ZARINPAL_API_BASE}/pg/v4/payment/verify.json"
+ZARINPAL_REVERSE_URL = f"{ZARINPAL_API_BASE}/pg/v4/payment/reverse.json"
 ZARINPAL_STARTPAY    = f"{ZARINPAL_API_BASE}/pg/StartPay/"
 ZARINPAL_CALLBACK_URL = config('ZARINPAL_CALLBACK_URL', default='http://localhost:8000/api/payments/callback')

config/settings/base.py

@@ -229,6 +229,9 @@ os.makedirs(BASE_DIR / 'logs', exist_ok=True)
 BACKEND_ROOT = config('DJANGO_HOST', default='http://localhost:8000/')
 FRONTEND_ROOT = config('FRONTEND_ROOT', default='http://localhost:3000/')
 FRONTEND_CALLBACK_URL = config('FRONTEND_CALLBACK_URL', default='http://localhost:3000/payments/result')
+PAYMENT_VERIFICATION_GRACE_SECONDS = config('PAYMENT_VERIFICATION_GRACE_SECONDS', cast=int, default=1800)
+PAYMENT_VERIFICATION_MAX_ATTEMPTS = config('PAYMENT_VERIFICATION_MAX_ATTEMPTS', cast=int, default=6)
+PAYMENT_VERIFICATION_DISPATCH_LEASE_SECONDS = config('PAYMENT_VERIFICATION_DISPATCH_LEASE_SECONDS', cast=int, default=900)
 GOOGLE_OAUTH_CLIENT_ID = config('GOOGLE_OAUTH_CLIENT_ID', default='')
 GOOGLE_OAUTH_CLIENT_SECRET = config('GOOGLE_OAUTH_CLIENT_SECRET', default='')
 GOOGLE_OAUTH_REDIRECT_URI = config('GOOGLE_OAUTH_REDIRECT_URI', default='')