init

backend/payments/models.py

@@ -0,0 +1,122 @@
+from django.db import models
+from django.db.models import Q, Count
+from django.core.exceptions import ValidationError
+from django.conf import settings
+from django.utils import timezone
+
+from utils.models import BaseModel
+from events.models import Event
+
+from ninja.errors import HttpError
+
+User = settings.AUTH_USER_MODEL
+
+
+class DiscountCode(BaseModel):
+    class Type(models.TextChoices):
+        PERCENT = "percent", "Percent"
+        FIXED   = "fixed",   "Fixed (IRR)"
+
+    code = models.CharField(max_length=64, unique=True)
+    type = models.CharField(max_length=10, choices=Type.choices, default=Type.PERCENT)
+    value = models.PositiveIntegerField()
+    max_discount = models.PositiveIntegerField(null=True, blank=True)
+    is_active = models.BooleanField(default=True)
+    starts_at = models.DateTimeField(null=True, blank=True)
+    ends_at   = models.DateTimeField(null=True, blank=True)
+    usage_limit_total = models.PositiveIntegerField(null=True, blank=True)
+    usage_limit_per_user = models.PositiveIntegerField(null=True, blank=True)
+    min_amount = models.PositiveIntegerField(null=True, blank=True)
+    applicable_events = models.ManyToManyField(Event, blank=True, related_name="discount_codes")
+
+    def __str__(self):
+        return f"{self.code} ({self.get_type_display()} {self.value})"
+    
+    def calculate_discount(self, event: Event, user: User):
+        if not event.price:
+            return (0, 0)
+         
+        if not self.is_active:
+            raise HttpError(400, "کد تخفیف نامعتبر یا غیرفعال است.")
+
+        n = timezone.now()
+        if self.starts_at and n < self.starts_at:
+            raise HttpError(400, "کد تخفیف هنوز فعال نشده است.")
+        if self.ends_at and n > self.ends_at:
+            raise HttpError(400, "کد تخفیف منقضی شده است.")
+
+        if self.applicable_events.exists() and not self.applicable_events.filter(pk=event.pk).exists():
+            raise HttpError(400, "کد تخفیف برای این رویداد قابل استفاده نیست.")
+
+        if self.min_amount and event.price < self.min_amount:
+            raise HttpError(400, "مبلغ سفارش کمتر از حداقل لازم برای این کد است.")
+
+        used_qs = Payment.objects.filter(discount_code=self, status__in=[Payment.OrderStatusChoices.PAID, Payment.OrderStatusChoices.PENDING])
+        if self.usage_limit_total is not None and used_qs.count() >= self.usage_limit_total:
+            raise HttpError(400, "حداکثر تعداد استفاده از این کد تخفیف تکمیل شده است.")
+
+        used_by_user = used_qs.filter(user=user).count()
+        if self.usage_limit_per_user is not None and used_by_user >= self.usage_limit_per_user:
+            raise HttpError(400, "شما حداکثر تعداد مجاز استفاده از این کد تخفیف را مصرف کرده‌اید.")
+
+        if self.type == DiscountCode.Type.FIXED:
+            disc = min(self.value, event.price)
+        else:
+            disc = (event.price * self.value) // 100
+            if self.max_discount:
+                disc = min(disc, self.max_discount)
+
+        final_amount = max(event.price - disc, 0)
+        if 0 < final_amount < 10_000:
+            raise HttpError(400, "با این تخفیف مبلغ قابل پرداخت به کمتر از ۱۰٬۰۰۰ ریال می‌رسد.")
+
+        return (final_amount, disc)
+
+
+class Payment(BaseModel):
+    class OrderStatusChoices(models.IntegerChoices):
+        INIT = 0, "Initiated"
+        PENDING = 1, "Pending"
+        PAID = 2, "Paid"
+        FAILED = 3, "Failed"
+        CANCELED = 4, "Canceled"
+
+    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)
+
+    base_amount = models.PositiveIntegerField(editable=False)
+    discount_code = models.ForeignKey(DiscountCode, on_delete=models.PROTECT, null=True, blank=True, editable=False, related_name="payments")
+    discount_amount = models.PositiveIntegerField(default=0, editable=False)
+    amount = models.PositiveIntegerField(editable=False)
+
+    registration = models.ForeignKey(
+        "events.Registration",
+        null=True,
+        blank=True,
+        on_delete=models.SET_NULL,
+        related_name="payments",
+        editable=False,
+    )
+    authority = models.CharField(max_length=64, unique=True, null=True, blank=True, editable=False)
+    status = models.IntegerField(choices=OrderStatusChoices.choices, default=OrderStatusChoices.INIT, editable=False)
+    ref_id = models.CharField(max_length=64, null=True, blank=True, editable=False)
+    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)
+
+    def clean(self):
+        if self.discount_amount and self.amount + self.discount_amount != self.base_amount:
+            raise ValidationError({"amount": "amount + discount_amount must equal base_amount"})
+
+    def save(self, *args, **kwargs):
+        self.full_clean()
+        return super().save(*args, **kwargs)
+
+    @property
+    def status_label(self):
+        """Human-readable label for the payment status."""
+        return self.get_status_display()
+
+    def __str__(self):
+        return f"{self.user.email}:{self.event} - {self.get_status_display()}"
+