feat: add recharge callback processing

apps/billing/models.py

@@ -154,6 +154,80 @@ class ExchangeRate(models.Model):
         super().save(*args, **kwargs)
 
 
+class RechargeOrder(models.Model):
+    class PayMethod(models.TextChoices):
+        WEIXIN = "weixin", "Weixin"
+        ALIPAY = "alipay", "Alipay"
+
+    class Status(models.TextChoices):
+        PENDING = "pending", "Pending"
+        PAID = "paid", "Paid"
+        FAILED = "failed", "Failed"
+        EXPIRED = "expired", "Expired"
+
+    order_no = models.CharField(max_length=64, unique=True)
+    user = models.ForeignKey(
+        settings.AUTH_USER_MODEL,
+        on_delete=models.PROTECT,
+        related_name="recharge_orders",
+    )
+    amount_money = models.DecimalField(max_digits=12, decimal_places=2)
+    currency = models.CharField(max_length=10, default="CNY")
+    pay_method = models.CharField(max_length=20, choices=PayMethod.choices)
+    exchange_rate = models.DecimalField(max_digits=12, decimal_places=4)
+    points_granted = models.BigIntegerField()
+    status = models.CharField(
+        max_length=20,
+        choices=Status.choices,
+        default=Status.PENDING,
+    )
+    code_url = models.TextField(blank=True)
+    expires_at = models.DateTimeField(null=True, blank=True)
+    payment_txn_no = models.CharField(max_length=128, blank=True)
+    paid_at = models.DateTimeField(null=True, blank=True)
+    created_at = models.DateTimeField(auto_now_add=True)
+    updated_at = models.DateTimeField(auto_now=True)
+
+    class Meta:
+        db_table = "recharge_order"
+        ordering = ("-created_at", "-id")
+        constraints = [
+            models.CheckConstraint(
+                condition=Q(amount_money__gt=0),
+                name="recharge_order_amount_money_positive",
+            ),
+            models.CheckConstraint(
+                condition=Q(exchange_rate__gt=0),
+                name="recharge_order_exchange_rate_positive",
+            ),
+            models.CheckConstraint(
+                condition=Q(points_granted__gt=0),
+                name="recharge_order_points_granted_positive",
+            ),
+        ]
+        indexes = [
+            models.Index(fields=("user", "created_at")),
+            models.Index(fields=("status", "created_at")),
+            models.Index(fields=("pay_method", "status")),
+        ]
+
+    def __str__(self) -> str:
+        return f"{self.order_no} {self.status}"
+
+    def clean(self) -> None:
+        super().clean()
+        self.order_no = str(self.order_no or "").strip()
+        self.currency = str(self.currency or "").strip().upper()
+        if not self.order_no:
+            raise ValidationError({"order_no": "Order number is required."})
+        if not self.currency:
+            raise ValidationError({"currency": "Currency is required."})
+
+    def save(self, *args, **kwargs) -> None:
+        self.full_clean()
+        super().save(*args, **kwargs)
+
+
 class PointsLedger(models.Model):
     class ChangeType(models.TextChoices):
         RECHARGE = "recharge", "Recharge"
@@ -196,6 +270,10 @@ class PointsLedger(models.Model):
                 fields=("ref_call", "change_type"),
                 name="unique_ledger_change_type_per_call",
             ),
+            models.UniqueConstraint(
+                fields=("ref_order_id", "change_type"),
+                name="unique_ledger_change_type_per_order",
+            ),
         ]
         indexes = [
             models.Index(fields=("user", "created_at")),