# django imports
from django.contrib.auth import login

# rest_framework imports
from rest_framework import generics, permissions
from rest_framework.authtoken.serializers import AuthTokenSerializer
from api.filters import UserFilter
from api.mixins import StaffEditorPermissionMixin
from api.models import User, Atoll, Island, TemporaryUser
from rest_framework.response import Response
from rest_framework import status
from rest_framework.exceptions import ValidationError
from rest_framework.decorators import api_view, permission_classes
from api.serializers import (
    AtollSerializer,
    IslandSerializer,
    CustomUserByWalletBalanceSerializer,
    OTPVerificationSerializer,
    TemporaryUserSerializer,
)
from django.shortcuts import get_object_or_404
from django.utils import timezone
from datetime import timedelta

# knox imports
from knox.views import LoginView as KnoxLoginView
from knox.models import AuthToken
from django_filters.rest_framework import DjangoFilterBackend
import re
from typing import cast, Dict, Any
from django.core.mail import send_mail
from django.db.models import Q
from api.sms import send_otp


# local apps import
from .serializers import (
    KnoxTokenSerializer,
    AuthSerializer,
    CustomUserSerializer,
    CustomReadOnlyUserSerializer,
    CustomReadOnlyUserByIDCardSerializer,
)

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."


class UpdateUserWalletView(generics.UpdateAPIView):
    # Create user API view
    serializer_class = CustomUserByWalletBalanceSerializer
    permission_classes = (permissions.IsAuthenticated,)
    queryset = User.objects.all()
    lookup_field = "pk"

    def update(self, request, *args, **kwargs):
        id_to_update = kwargs.get("pk")
        user_id = request.user.id
        print(f"User ID: {user_id}")
        print(f"ID to update: {id_to_update}")
        if user_id != id_to_update:
            return Response(
                {"message": "You are not authorized to update this user."},
                status=status.HTTP_403_FORBIDDEN,
            )
        wallet_balance = request.data.get("wallet_balance")
        if not wallet_balance:
            return Response(
                {"message": "wallet_balance is required."},
                status=status.HTTP_400_BAD_REQUEST,
            )
        user = self.get_object()
        user.wallet_balance = wallet_balance
        user.save()
        return Response({"message": "Wallet balance updated successfully."})


class CreateTemporaryUserView(generics.CreateAPIView):
    # Create user API view
    serializer_class = TemporaryUserSerializer
    permission_classes = (permissions.AllowAny,)
    queryset = TemporaryUser.objects.all()
    throttle_classes = []

    def post(self, request, *args, **kwargs):
        # Extract required fields from request data
        username = request.data.get("username")
        address = request.data.get("address")
        mobile = request.data.get("mobile")
        acc_no = request.data.get("acc_no")
        id_card = request.data.get("id_card")
        dob = request.data.get("dob")
        atoll_id = request.data.get("atoll")
        island_id = request.data.get("island")
        terms_accepted = request.data.get("terms_accepted")
        policy_accepted = request.data.get("policy_accepted")
        firstname = request.data.get("firstname")
        lastname = request.data.get("lastname")

        current_date = timezone.now()
        try:
            dob = timezone.datetime.strptime(dob, "%Y-%m-%d").date()
        except ValueError:
            return Response(
                {"message": "Invalid date format for DOB. Use YYYY-MM-DD."}, status=400
            )

        age_from_dob = (
            current_date.year
            - dob.year
            - ((current_date.month, current_date.day) < (dob.month, dob.day))
        )

        if age_from_dob < 18:
            return Response({"message": ErrorMessages.UNDERAGE_ERROR}, status=400)

        if (
            TemporaryUser.objects.filter(t_mobile=mobile).exists()
            or User.objects.filter(mobile=mobile).exists()
        ):
            return Response({"message": ErrorMessages.MOBILE_EXISTS}, status=400)
        if (
            TemporaryUser.objects.filter(t_username=username).exists()
            or User.objects.filter(username=username).exists()
        ):
            return Response({"message": ErrorMessages.USERNAME_EXISTS}, status=400)
        if (
            TemporaryUser.objects.filter(t_id_card=id_card).exists()
            or User.objects.filter(id_card=id_card).exists()
        ):
            return Response({"message": "ID card already exists."}, status=400)
        if (
            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)
        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)

        # Validate required fields first
        validation_error = self.validate_required_fields(request.data)
        if validation_error:
            return validation_error

        # Fetch Atoll and Island instances
        try:
            atoll = Atoll.objects.get(id=atoll_id)
            island = Island.objects.get(id=island_id)
        except Atoll.DoesNotExist:
            return Response({"message": "Atoll not found."}, status=404)
        except Island.DoesNotExist:
            return Response({"message": "Island not found."}, status=404)

        # Create user
        temp_user = TemporaryUser.objects.create(
            t_first_name=firstname,
            t_last_name=lastname,
            t_username=str(username),
            t_email=None,
            t_address=address,
            t_mobile=mobile,
            t_acc_no=acc_no,
            t_id_card=id_card,
            t_dob=dob,
            t_atoll=atoll,
            t_island=island,
            t_terms_accepted=terms_accepted,
            t_policy_accepted=policy_accepted,
        )
        otp_expiry = timezone.now() + timedelta(minutes=3)
        formatted_time = otp_expiry.strftime("%d/%m/%Y %H:%M:%S")
        otp = temp_user.generate_otp()
        send_otp(
            temp_user.t_mobile,
            otp,
            f"Your Registration SARLink OTP: {otp}. \nExpires at {formatted_time}. \n\n- SAR Link",
        )
        serializer = self.get_serializer(temp_user)
        headers = self.get_success_headers(serializer.data)
        return Response(
            serializer.data, status=status.HTTP_201_CREATED, headers=headers
        )

    def validate_required_fields(self, data):
        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


class VerifyOTPView(generics.GenericAPIView):
    permission_classes = (permissions.AllowAny,)
    serializer_class = OTPVerificationSerializer
    throttle_classes = []

    def post(self, request):
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        data = request.data
        mobile = data.get("mobile")
        t_user = get_object_or_404(TemporaryUser, t_mobile=mobile)
        if not t_user:
            return Response({"message": "User not found."}, status=404)

        if User.objects.filter(username=t_user.t_username).exists():
            return Response(
                {"message": "User with this mobile number already registered."},
                status=400,
            )
        try:
            temp_user = TemporaryUser.objects.get(t_mobile=data["mobile"])
        except TemporaryUser.DoesNotExist:
            return Response({"message": "User not found."}, status=404)

        if temp_user.is_expired():
            return Response({"message": "OTP expired."}, status=400)

        if not temp_user.verify_otp(data["otp"]):
            return Response({"message": "Invalid OTP."}, status=400)

        # Create real user
        User.objects.create_user(
            first_name=temp_user.t_first_name,
            last_name=temp_user.t_last_name,
            username=temp_user.t_username,
            password="",
            address=temp_user.t_address,
            mobile=temp_user.t_mobile,
            acc_no=temp_user.t_acc_no,
            id_card=temp_user.t_id_card,
            dob=temp_user.t_dob,
            atoll=temp_user.t_atoll,
            island=temp_user.t_island,
            terms_accepted=temp_user.t_terms_accepted,
            policy_accepted=temp_user.t_policy_accepted,
        )

        # You can now trigger registry verification as a signal or task
        temp_user.otp_verified = True
        temp_user.save()

        return Response({"message": "User created successfully."})


class LoginView(KnoxLoginView):
    # login view extending KnoxLoginView
    serializer_class = AuthSerializer
    permission_classes = (permissions.AllowAny,)
    throttle_scope = "login"

    def post(self, request, format=None):
        try:
            serializer = AuthTokenSerializer(data=request.data)
            serializer.is_valid(raise_exception=True)
            user = cast(Dict[str, Any], serializer.validated_data)["user"]
            login(request, user)
            response = super(LoginView, self).post(request, format=None)
            return response
        except ValidationError as e:
            message = "Unable to log in with provided credentials."
            if (
                hasattr(e, "detail")
                and isinstance(e.detail, list)
                and len(e.detail) > 0
            ):
                message = e.detail[0]
            return Response({"message": message}, status=status.HTTP_400_BAD_REQUEST)


class ManageUserView(generics.RetrieveUpdateAPIView):
    """Manage the authenticated user"""

    serializer_class = CustomUserSerializer
    permission_classes = (permissions.IsAuthenticated,)

    def get_object(self):
        """Retrieve and return authenticated user"""
        return self.request.user


class KnoxTokenListApiView(
    StaffEditorPermissionMixin,
    generics.ListAPIView,
):
    # Create user API view
    serializer_class = KnoxTokenSerializer
    permission_classes = (permissions.IsAuthenticated,)
    queryset = AuthToken.objects.all()

    def get(self, request, *args, **kwargs):
        user_id = getattr(request.user, "id", None)
        if user_id is None:
            return Response({"error": "User ID not found"}, status=400)
        queryset = AuthToken.objects.filter(user_id=user_id)
        data = KnoxTokenSerializer(queryset, many=True).data
        return Response({"data": data})


class ListUserView(StaffEditorPermissionMixin, generics.ListAPIView):
    # Create user API view
    serializer_class = CustomReadOnlyUserSerializer
    filter_backends = [DjangoFilterBackend]
    filterset_fields = "__all__"
    filterset_class = UserFilter
    queryset = User.objects.all()


@api_view(["GET"])
def filter_user(request):
    id_card = request.GET.get("id_card", "").strip() or None
    mobile = request.GET.get("mobile", "").strip() or None

    if not id_card and not mobile:
        return Response({"ok": False})

    filters = Q()
    if id_card is not None:
        filters |= Q(id_card=id_card)
    if mobile is not None:
        filters |= Q(mobile=mobile)

    user = User.objects.filter(filters).first()

    print(f"Querying with filters: {filters}")
    print(f"Found user: {user}")

    return Response(
        {"ok": True, "verified": user.verified}
        if user
        else {"ok": False, "verified": False}
    )


@api_view(["GET"])
def filter_temporary_user(request):
    id_card = request.GET.get("id_card", "").strip() or None
    mobile = request.GET.get("mobile", "").strip() or None

    if not id_card and not mobile:
        return Response({"ok": False})

    filters = Q()
    if id_card is not None:
        filters |= Q(t_id_card=id_card)
    if mobile is not None:
        filters |= Q(t_mobile=mobile)

    user = TemporaryUser.objects.filter(filters).first()

    print(f"Querying with filters: {filters}")
    print(f"Found temporary user: {user}")

    return Response(
        {"ok": True, "otp_verified": user.otp_verified}
        if user
        else {"ok": False, "otp_verified": False}
    )


class ListUserByIDCardView(generics.ListAPIView):
    # Create user API view
    permission_classes = (permissions.AllowAny,)
    serializer_class = CustomReadOnlyUserByIDCardSerializer
    filter_backends = [DjangoFilterBackend]
    filterset_fields = "__all__"
    filterset_class = UserFilter
    queryset = User.objects.all()


class UserDetailAPIView(StaffEditorPermissionMixin, generics.RetrieveAPIView):
    queryset = User.objects.all()
    serializer_class = CustomReadOnlyUserSerializer
    lookup_field = "pk"

    def retrieve(self, request, *args, **kwargs):
        instance = self.get_object()
        serializer = self.get_serializer(instance)
        data = serializer.data

        # Customize the response format

        return Response(data)


@api_view(["GET"])
def healthcheck(request):
    return Response({"status": "Good"}, status=status.HTTP_200_OK)


@api_view(["POST"])
@permission_classes((permissions.AllowAny,))
def test_email(request):
    send_mail(
        "Subject here",
        "Here is the message.",
        "noreply@sarlink.net",
        ["shihaam@shihaam.me"],
        fail_silently=False,
    )
    return Response({"status": "ok"}, status=status.HTTP_200_OK)


class CreateAtollView(StaffEditorPermissionMixin, generics.CreateAPIView):
    serializer_class = AtollSerializer
    queryset = Atoll.objects.all()

    def create(self, request, *args, **kwargs):
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        name = serializer.validated_data.get("name")
        print(name)
        if Atoll.objects.filter(name=name).exists():
            return Response({"message": "Atoll name already exists."}, status=400)
        return super().create(request, *args, **kwargs)


class ListAtollView(generics.ListAPIView):
    permission_classes = (permissions.AllowAny,)
    serializer_class = AtollSerializer
    queryset = Atoll.objects.all()
    throttle_classes = ()  # override throttling


class RetrieveUpdateDestroyAtollView(
    StaffEditorPermissionMixin, generics.RetrieveUpdateDestroyAPIView
):
    serializer_class = AtollSerializer
    queryset = Atoll.objects.all()
    lookup_field = "pk"

    def update(self, request, *args, **kwargs):
        instance = self.get_object()
        serializer = self.get_serializer(instance, data=request.data, partial=True)
        serializer.is_valid(raise_exception=True)
        name = serializer.validated_data.get("name")
        if name and Atoll.objects.filter(name=name).exclude(pk=instance.pk).exists():
            return Response({"message": "Atoll name already exists."}, status=400)
        return super().update(request, *args, **kwargs)


class ListCreateIslandView(StaffEditorPermissionMixin, generics.ListCreateAPIView):
    serializer_class = IslandSerializer
    queryset = Island.objects.all()

    def create(self, request, *args, **kwargs):
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        name = serializer.validated_data.get("name")
        if Island.objects.filter(name=name).exists():
            return Response({"message": "Island name already exists."}, status=400)
        return super().create(request, *args, **kwargs)


class RetrieveUpdateDestroyIslandView(
    StaffEditorPermissionMixin, generics.RetrieveUpdateDestroyAPIView
):
    serializer_class = IslandSerializer
    queryset = Island.objects.all()
    lookup_field = "pk"

    def update(self, request, *args, **kwargs):
        instance = self.get_object()
        serializer = self.get_serializer(instance, data=request.data, partial=True)
        serializer.is_valid(raise_exception=True)
        name = serializer.validated_data.get("name")
        if name and Island.objects.filter(name=name).exclude(pk=instance.pk).exists():
            return Response({"message": "Island name already exists."}, status=400)
        return super().update(request, *args, **kwargs)