Initial commit

backend/apps/accounts/services/otp.py

@@ -0,0 +1,83 @@
+import logging
+import secrets
+from dataclasses import dataclass
+
+from django.conf import settings
+from django.contrib.auth.hashers import check_password, make_password
+from django.utils import timezone
+
+from apps.accounts.models import OtpChannel, PhoneOTP
+
+logger = logging.getLogger(__name__)
+
+
+@dataclass
+class OtpSendResult:
+    request_id: str
+    expires_at: str
+
+
+class BaseOtpProvider:
+    def send_sms(self, to_number: str, message: str) -> None:
+        raise NotImplementedError
+
+    def send_whatsapp(self, to_number: str, message: str) -> None:
+        raise NotImplementedError
+
+
+class ConsoleOtpProvider(BaseOtpProvider):
+    def send_sms(self, to_number: str, message: str) -> None:
+        logger.info("OTP SMS to %s: %s", to_number, message)
+
+    def send_whatsapp(self, to_number: str, message: str) -> None:
+        logger.info("OTP WhatsApp to %s: %s", to_number, message)
+
+
+PROVIDERS = {
+    "console": ConsoleOtpProvider,
+}
+
+
+def get_provider() -> BaseOtpProvider:
+    provider_key = settings.OTP_PROVIDER
+    provider_cls = PROVIDERS.get(provider_key)
+    if not provider_cls:
+        raise ValueError(f"Unknown OTP provider: {provider_key}")
+    return provider_cls()
+
+
+def generate_code(length: int = 6) -> str:
+    digits = "0123456789"
+    return "".join(secrets.choice(digits) for _ in range(length))
+
+
+def create_and_send_otp(phone_number: str, channel: str) -> OtpSendResult:
+    provider = get_provider()
+    code = generate_code()
+    otp = PhoneOTP.objects.create(
+        phone_number=phone_number,
+        channel=channel,
+        provider=settings.OTP_PROVIDER,
+        code_hash=make_password(code),
+        expires_at=PhoneOTP.expiry_at(),
+    )
+
+    message = f"Your verification code is {code}. It expires in {settings.OTP_EXPIRY_MINUTES} minutes."
+    if channel == OtpChannel.SMS:
+        provider.send_sms(phone_number, message)
+    elif channel == OtpChannel.WHATSAPP:
+        provider.send_whatsapp(phone_number, message)
+    else:
+        raise ValueError("Unsupported OTP channel")
+
+    return OtpSendResult(request_id=str(otp.id), expires_at=otp.expires_at.isoformat())
+
+
+def verify_otp(otp: PhoneOTP, code: str) -> bool:
+    if otp.verified_at or otp.is_expired():
+        return False
+    if not check_password(code, otp.code_hash):
+        return False
+    otp.verified_at = timezone.now()
+    otp.save(update_fields=["verified_at"])
+    return True