feat: changed TPV behaviour

shop/utils.py

@@ -1,17 +1,28 @@
+import base64
+import hashlib
+import hmac
+import json
 from decimal import Decimal
 
+import pyDes
 from django.contrib.auth import get_user_model
+from django.db import transaction
+from django.utils import timezone
+from django.utils.text import gettext_lazy as _
 
+from shop.exceptions import RedsysPaymentException, RedsysValidationException
 from shop.models import (
     Cart,
     CustomerAddress,
     Order,
     OrderLine,
+    Payment,
     Product,
     ProductBatch,
     ProductPrice,
     ShippingMethod,
 )
+from shop.settings import ERROR_CODES
 
 User = get_user_model()
 
@@ -148,3 +159,117 @@ def add_shipping_order_line(order, shipping_method):
         total=shipping_total,
     )
     order.calculate_total_from_lines()
+
+
+def compute_signature(salt, payload, key):
+    """
+    :param salt: order number (Ds_Order or Ds_Merchant_Order)
+    :param payload: Ds_MerchantParameters
+    :param key: shared secret (aka key) from the Redsys Administration Module
+    :return:
+    """
+    b64_key = base64.b64decode(key)
+
+    des3 = pyDes.triple_des(
+        b64_key, mode=pyDes.CBC, IV="\0" * 8, pad="\0", padmode=pyDes.PAD_NORMAL
+    )
+    pepper = des3.encrypt(str(salt))
+
+    payload_hash = hmac.new(pepper, payload.encode(), hashlib.sha256).digest()
+    return base64.b64encode(payload_hash)
+
+
+def validate_payment_for_order(request, order: Order) -> Decimal:
+    """
+    example_response_data = {
+        'Ds_MerchantCode': '999008881',
+        'Ds_Terminal': '001',
+        'Ds_Order': 'a082bd1cda0b488786f23a62e89107c0',
+        'Ds_Amount': '13532',
+        'Ds_Currency': '978',
+        'Ds_Date': '20/03/2024',
+        'Ds_Hour': '12:21',
+        'Ds_SecurePayment': '1',
+        'Ds_Card_Number': '454881******1156',
+        'Ds_Card_Country': '724',
+        'Ds_Response': '0000',
+        'Ds_MerchantData': '',
+        'Ds_TransactionType': '0',
+        'Ds_ConsumerLanguage': '1',
+        'Ds_AuthorisationCode': '182670',
+        'Ds_Card_Brand': '1',
+        'Ds_ProcessedPayMethod': '80',
+        'Ds_ECI': '05',
+        'Ds_Response_Description': 'OPERACION AUTORIZADA'
+    }
+
+    Raises AssertionError
+    """
+    data = request.POST
+
+    merchant_parameters = data.get("Ds_MerchantParameters")
+
+    if not merchant_parameters:
+        raise RedsysValidationException(
+            _("No se ha recibido ningún valor para Ds_MerchantParameters")
+        )
+
+    merchant_params = decode_b64_string(merchant_parameters)
+    result = json.loads(merchant_params)
+
+    order_code = result.get("Ds_Order")
+    assert order_code == order.code
+
+    status_code = result.get("Ds_Response")
+
+    if int(status_code) > 100:
+        reason = ERROR_CODES.get(status_code, _("Error no tipificado"))
+
+        raise RedsysPaymentException(_(f"No se ha realizado el pago. Motivo: {reason}"))
+
+    amount = Decimal(result.get("Ds_Amount")) / 100
+
+    return amount
+
+
+def decode_b64_string(value: str):
+    return base64.b64decode(value).decode()
+
+
+def decode_b64_dict(value: str):
+    return json.loads(decode_b64_string(value))
+
+
+def validate_expiry_date(expiry_date: str):
+    if len(expiry_date) != 4:
+        return False
+
+    month, year = int(expiry_date[2:4]), int(expiry_date[:2])
+
+    if month < 1 or month > 12:
+        return False
+
+    current_year = int(str(timezone.now().year)[2:])
+    current_month = timezone.now().month
+
+    if year < current_year:
+        return False
+
+    if year == current_year and month > current_month:
+        return False
+
+    return True
+
+
+def pay_order(order: Order, amount_paid: Decimal):
+    with transaction.atomic() as tx:
+        payment = Payment.objects.create(
+            amount=amount_paid,
+            order=order,
+            user=order.user,
+            method=Payment.MethodChoices.REDSYS,
+        )
+
+        if amount_paid >= order.total:
+            order.status = Order.Statuses.STATUS_PAID
+            order.save()