import logging
import json
import urllib.request
import urllib.error
from django.conf import settings
from django.core.cache import cache
from rest_framework import status, permissions
from rest_framework.response import Response
from rest_framework.views import APIView
from django.contrib.auth.models import User
from .serializers import UserRegisterSerializer

audit_logger = logging.getLogger('audit')

class UserRegisterView(APIView):
    permission_classes = [permissions.AllowAny]

    def post(self, request):
        serializer = UserRegisterSerializer(data=request.data)
        if serializer.is_valid():
            serializer.save()
            audit_logger.info(f"AUDIT - User Register: Username '{serializer.validated_data.get('username')}' registered successfully.")
            return Response({"message": "User registered successfully"}, status=status.HTTP_201_CREATED)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

class UserProfileView(APIView):
    permission_classes = [permissions.IsAuthenticated]

    def get(self, request):
        user = request.user
        profile = getattr(user, 'customer_profile', None)
        return Response({
            "username": user.username,
            "email": user.email,
            "phone": profile.phone if profile else "",
            "address": profile.default_address if profile else ""
        })

    def put(self, request):
        user = request.user
        profile = getattr(user, 'customer_profile', None)
        user.email = request.data.get('email', user.email)
        user.save()
        if profile:
            profile.phone = request.data.get('phone', profile.phone)
            profile.default_address = request.data.get('address', profile.default_address)
            profile.save()
        return Response({"message": "Profile updated successfully"})

def send_msg91_whatsapp_direct(mobile_number, otp_code, template_name="mobile_number_verification"):
    clean_digits = ''.join(c for c in str(mobile_number) if c.isdigit())
    target_number = f"91{clean_digits}" if len(clean_digits) == 10 else clean_digits

    msg91_payload = {
        "integrated_number": "918610694498",
        "content_type": "template",
        "payload": {
            "messaging_product": "whatsapp",
            "type": "template",
            "template": {
                "name": template_name,
                "language": {
                    "code": "en",
                    "policy": "deterministic"
                },
                "namespace": None,
                "to_and_components": [
                    {
                        "to": [target_number],
                        "components": {
                            "body_1": {
                                "type": "text",
                                "value": str(otp_code)
                            },
                            "button_1": {
                                "subtype": "url",
                                "type": "text",
                                "value": str(otp_code)
                            }
                        }
                    }
                ]
            }
        }
    }

    try:
        req_data = json.dumps(msg91_payload).encode('utf-8')
        req = urllib.request.Request(
            'https://control.msg91.com/api/v5/whatsapp/whatsapp-outbound-message/bulk/',
            data=req_data,
            headers={
                'accept': 'application/json',
                'authkey': '563180AluxJHIeTGn6aaf97aeP1',
                'content-type': 'application/json'
            }
        )
        with urllib.request.urlopen(req, timeout=10) as resp:
            body_bytes = resp.read()
            try:
                res_data = json.loads(body_bytes.decode('utf-8'))
            except Exception:
                res_data = {"text": body_bytes.decode('utf-8', errors='ignore')}
            return resp.status, res_data
    except urllib.error.HTTPError as e:
        err_body = e.read().decode('utf-8', errors='ignore')
        try:
            err_data = json.loads(err_body)
        except Exception:
            err_data = {"text": err_body}
        return e.code, err_data
    except Exception as e:
        return 500, {"error": str(e)}

class SendWhatsAppOTPView(APIView):
    permission_classes = [permissions.AllowAny]

    def post(self, request):
        mobile_number = request.data.get('mobile_number')
        otp_code = request.data.get('otp_code')
        template_name = request.data.get('template_name', 'mobile_number_verification')
        purpose = request.data.get('purpose', 'login')

        if not mobile_number or not otp_code:
            return Response({"error": "mobile_number and otp_code are required"}, status=status.HTTP_400_BAD_REQUEST)

        clean_phone = str(mobile_number).replace('+', '').strip()
        raw_10 = clean_phone[-10:] if len(clean_phone) >= 10 else clean_phone

        # Account existence validation
        from django.db.models import Q
        user_exists = None
        try:
            from orders.models import CustomerProfile
            user_exists = (
                User.objects.filter(Q(username__icontains=raw_10) | Q(email__icontains=raw_10)).exists()
                or CustomerProfile.objects.filter(Q(phone__icontains=raw_10) | Q(user__username__icontains=raw_10)).exists()
            )
        except Exception as db_err:
            audit_logger.warning(f"DB lookup notice for {mobile_number}: {db_err}")
            user_exists = None

        if purpose == 'login' and user_exists is False:
            audit_logger.warning(f"AUDIT - Login attempt for non-existent mobile: '{mobile_number}'")
            return Response({
                "status": "error",
                "message": "Account not found. Please create a patron account first."
            }, status=status.HTTP_404_NOT_FOUND)

        if purpose == 'register' and user_exists is True:
            audit_logger.warning(f"AUDIT - Register attempt for existing mobile: '{mobile_number}'")
            return Response({
                "status": "error",
                "message": "An account with this mobile number already exists. Please Sign In."
            }, status=status.HTTP_400_BAD_REQUEST)

        audit_logger.info(f"AUDIT - Send WhatsApp OTP: mobile '{mobile_number}', OTP '{otp_code}'")

        # Store OTP in backend cache for 5 minutes (300 seconds)
        cache.set(f"whatsapp_otp_{clean_phone}", str(otp_code), timeout=300)

        whatsapp_urls = [
            getattr(settings, 'WHATSAPP_SERVICE_URL', 'https://betawhatsapp.tradhox.com/api/send/'),
            'https://betawhatsapp.tradhox.com/send/',
            'http://betawhatsapp.tradhox.com/api/send/',
            'http://betawhatsapp.tradhox.com/send/',
            'http://127.0.0.1:8081/api/send/',
            'http://127.0.0.1:8081/send/'
        ]

        payload = {
            "mobile_number": mobile_number,
            "otp_code": otp_code,
            "template_name": template_name
        }

        req_data = json.dumps(payload).encode('utf-8')
        last_error = None
        res_data = None
        status_code = 500

        for url in whatsapp_urls:
            try:
                req = urllib.request.Request(
                    url,
                    data=req_data,
                    headers={'Content-Type': 'application/json', 'User-Agent': 'TradhoxBackend/1.0'}
                )
                with urllib.request.urlopen(req, timeout=6) as resp:
                    status_code = resp.status
                    body_bytes = resp.read()
                    try:
                        res_data = json.loads(body_bytes.decode('utf-8'))
                    except Exception:
                        res_data = {"text": body_bytes.decode('utf-8', errors='ignore')}

                if status_code == 200 and res_data.get('status') != 'error':
                    return Response({
                        "status": "success",
                        "message": f"WhatsApp OTP dispatched to {mobile_number}",
                        "mobile_number": mobile_number,
                        "gateway_response": res_data
                    }, status=status.HTTP_200_OK)
            except urllib.error.HTTPError as e:
                status_code = e.code
                err_body = e.read().decode('utf-8', errors='ignore')
                try:
                    res_data = json.loads(err_body)
                except Exception:
                    res_data = {"text": err_body}
                last_error = f"HTTP {e.code}: {res_data}"
                audit_logger.warning(f"WhatsApp gateway attempt {url} returned HTTP {e.code}: {res_data}")
            except Exception as e:
                last_error = str(e)
                audit_logger.warning(f"WhatsApp gateway attempt {url} failed: {e}")

        # Fallback directly to MSG91 engine
        audit_logger.info(f"Attempting direct MSG91 WhatsApp dispatch for {mobile_number}")
        msg91_status, msg91_res = send_msg91_whatsapp_direct(mobile_number, otp_code, template_name)

        if msg91_status == 200 and msg91_res.get('status') == 'success':
            return Response({
                "status": "success",
                "message": f"WhatsApp OTP dispatched to {mobile_number}",
                "mobile_number": mobile_number,
                "gateway_response": msg91_res
            }, status=status.HTTP_200_OK)

        if status_code == 200:
            return Response({
                "status": "success",
                "message": f"WhatsApp OTP request submitted for {mobile_number}",
                "mobile_number": mobile_number,
                "gateway_response": res_data
            }, status=status.HTTP_200_OK)
        else:
            return Response({
                "status": "error",
                "message": f"WhatsApp service gateway error: {last_error or msg91_res}",
                "mobile_number": mobile_number
            }, status=status.HTTP_500_INTERNAL_SERVER_ERROR)

class VerifyOTPView(APIView):
    permission_classes = [permissions.AllowAny]

    def post(self, request):
        mobile_number = request.data.get('mobile_number')
        otp_code = request.data.get('otp_code')

        if not mobile_number or not otp_code:
            return Response({"error": "mobile_number and otp_code are required"}, status=status.HTTP_400_BAD_REQUEST)

        clean_phone = str(mobile_number).replace('+', '').strip()
        stored_otp = cache.get(f"whatsapp_otp_{clean_phone}")

        if stored_otp and str(stored_otp).strip() == str(otp_code).strip():
            audit_logger.info(f"AUDIT - OTP Verification SUCCESS: mobile '{mobile_number}'")
            return Response({
                "status": "success",
                "message": "OTP verified successfully"
            }, status=status.HTTP_200_OK)
        else:
            audit_logger.warning(f"AUDIT - OTP Verification FAILED: mobile '{mobile_number}', submitted '{otp_code}', expected '{stored_otp}'")
            return Response({
                "status": "error",
                "message": "Invalid or expired OTP verification code. Access denied."
            }, status=status.HTTP_400_BAD_REQUEST)