refactor(view): extract validation logic from CreateTemporaryUserView to

reduce cyclomatic complexity 🔨

api/helpers.py

@@ -0,0 +1,83 @@
+from rest_framework.response import Response
+from typing import Optional
+from datetime import date
+from django.utils import timezone
+import re
+
+
+ID_CARD_PATTERN = r"^[A-Z]{1,2}[0-9]{6,7}$"
+MOBILE_PATTERN = r"^[7|9][0-9]{6}$"
+ACCOUNT_NUMBER_PATTERN = r"^(7\d{12}|9\d{16})$"
+
+
+class ErrorMessages:
+    USERNAME_EXISTS = "Username already exists."
+    MOBILE_EXISTS = "Mobile number already exists."
+    INVALID_ID_CARD = "Please enter a valid ID card number."
+    ID_CARD_EXISTS = "ID card already exists."
+    INVALID_MOBILE = "Please enter a valid mobile number."
+    INVALID_ACCOUNT = "Please enter a valid account number."
+    UNDERAGE_ERROR = "You must be 18 and above to signup."
+
+
+def validate_required_fields(data) -> Optional[Response]:
+    required_fields = {
+        "firstname": "First name",
+        "lastname": "Last name",
+        "username": "Username",
+        "address": "Address",
+        "mobile": "Mobile number",
+        "acc_no": "Account number",
+        "id_card": "ID card",
+        "dob": "Date of birth",
+        "atoll": "Atoll",
+        "island": "Island",
+    }
+
+    for field, label in required_fields.items():
+        if not data.get(field):
+            return Response({"message": f"{label} is required."}, status=400)
+
+    if data.get("terms_accepted") is None:
+        return Response({"message": "Terms acceptance is required."}, status=400)
+    if data.get("policy_accepted") is None:
+        return Response({"message": "Policy acceptance is required."}, status=400)
+
+    return None
+
+
+from .models import TemporaryUser, User
+
+def validate_unique_fields(username, mobile, id_card) -> Optional[Response]:
+    if mobile and (TemporaryUser.objects.filter(t_mobile=mobile).exists() or User.objects.filter(mobile=mobile).exists()):
+        return Response({"message": ErrorMessages.MOBILE_EXISTS}, status=400)
+
+    if username and (TemporaryUser.objects.filter(t_username=username).exists() or User.objects.filter(username=username).exists()):
+        return Response({"message": ErrorMessages.USERNAME_EXISTS}, status=400)
+
+    if id_card and (TemporaryUser.objects.filter(t_id_card=id_card).exists() or User.objects.filter(id_card=id_card).exists()):
+        return Response({"message": ErrorMessages.ID_CARD_EXISTS}, status=400)
+
+    return None
+
+
+
+
+def validate_patterns(id_card, mobile, acc_no) -> Optional[Response]:
+    if id_card and not re.match(ID_CARD_PATTERN, id_card):
+        return Response({"message": ErrorMessages.INVALID_ID_CARD}, status=400)
+
+    if mobile is None or not re.match(MOBILE_PATTERN, mobile):
+        return Response({"message": ErrorMessages.INVALID_MOBILE}, status=400)
+
+    if acc_no is None or not re.match(ACCOUNT_NUMBER_PATTERN, acc_no):
+        return Response({"message": ErrorMessages.INVALID_ACCOUNT}, status=400)
+
+    return None
+
+
+
+
+def calculate_age(dob: date) -> int:
+    today = timezone.now().date()
+    return today.year - dob.year - ((today.month, today.day) < (dob.month, dob.day))