from django.http import JsonResponse
from django.utils.decorators import method_decorator
from django.views.decorators.csrf import csrf_exempt
from django.forms.models import model_to_dict
from django.contrib.auth import authenticate, logout
from rest_framework.views import APIView
from rest_framework.authtoken.models import Token
import json

from .models import User
from mobile_api.utils import validate_token_and_get_user


def _partner_user_to_dict(user, request=None):
    """Serialize partner-related User for JSON (same structure as _user_to_dict)."""
    data = model_to_dict(
        user,
        fields=[
            "id",
            "username",
            "email",
            "phone_number",
            "role",
            "is_staff",
            "is_customer",
            "is_user",
            "pincode",
            "district",
            "state",
            "country",
            "place",
            "latitude",
            "longitude",
            "first_name",
            "last_name",
        ],
    )
    # Add profile picture URL if exists
    if getattr(user, "profile_picture", None):
        if request:
            data["profile_picture"] = user.profile_picture.url
        else:
            data["profile_picture"] = user.profile_picture.url
    else:
        data["profile_picture"] = None
    return data


def _user_to_dict(user, request=None):
    """Serialize any User for JSON (admin/staff or partner)."""
    return _partner_user_to_dict(user, request)


@method_decorator(csrf_exempt, name="dispatch")
class PartnerLoginAPI(APIView):
    """
    Partner Login API.
    Body: username (or email), password (required).
    Returns: token, user data.
    """

    def post(self, request):
        try:
            # Parse JSON or form data
            is_multipart = request.content_type and "multipart/form-data" in request.content_type
            if is_multipart:
                data = request.POST.dict()
            else:
                try:
                    data = json.loads(request.body)
                except json.JSONDecodeError:
                    return JsonResponse(
                        {"status": "error", "message": "Invalid JSON"},
                        status=400,
                    )

            username = data.get("username") or data.get("email")
            password = data.get("password")

            if not username or not password:
                return JsonResponse(
                    {"status": "error", "message": "username and password are required."},
                    status=400,
                )

            # Authenticate user
            user = authenticate(request, username=username, password=password)
            if not user:
                return JsonResponse(
                    {"status": "error", "message": "Invalid username or password."},
                    status=401,
                )

            # Check if user has partner role
            partner_roles = ["partner", "partner_manager", "partner_staff"]
            if user.role not in partner_roles:
                return JsonResponse(
                    {"status": "error", "message": "You are not authorized to access partner portal."},
                    status=403,
                )

            # Get or create token
            token, _ = Token.objects.get_or_create(user=user)

            return JsonResponse(
                {
                    "status": "success",
                    "message": "Login successful",
                    "token": token.key,
                    "user": _partner_user_to_dict(user, request),
                },
                status=200,
            )

        except Exception as e:
            return JsonResponse({"status": "error", "message": str(e)}, status=500)


@method_decorator(csrf_exempt, name="dispatch")
class PartnerLogoutAPI(APIView):
    """
    Partner Logout API.
    Body: token, username (required).
    Returns: success message.
    """

    def post(self, request):
        try:
            user, token, data, error_response = validate_token_and_get_user(request, error_status_code=True)
            if error_response:
                return error_response

            # Check if user has partner role
            partner_roles = ["partner", "partner_manager", "partner_staff"]
            if user.role not in partner_roles:
                return JsonResponse(
                    {"status": "error", "message": "You are not authorized to access partner portal."},
                    status=403,
                )

            # Delete token
            token.delete()

            return JsonResponse(
                {
                    "status": "success",
                    "message": "Logged out successfully.",
                },
                status=200,
            )

        except Exception as e:
            return JsonResponse({"status": "error", "message": str(e)}, status=500)


@method_decorator(csrf_exempt, name="dispatch")
class PartnerDashboardAPI(APIView):
    """
    Partner Dashboard API.
    Body: token, username (required).
    Returns: dashboard statistics.
    """

    def post(self, request):
        try:
            user, token, data, error_response = validate_token_and_get_user(request, error_status_code=True)
            if error_response:
                return error_response

            # Check if user has partner role
            partner_roles = ["partner", "partner_manager", "partner_staff"]
            if user.role not in partner_roles:
                return JsonResponse(
                    {"status": "error", "message": "You are not authorized to access this page."},
                    status=403,
                )

            # Get statistics for partner users (including partner_customer)
            all_partner_roles = ["partner", "partner_manager", "partner_staff", "partner_customer"]
            partner_users = User.objects.filter(role__in=all_partner_roles)
            total_partner_users = partner_users.count()

            return JsonResponse(
                {
                    "status": "success",
                    "dashboard": {
                        "total_partner_users": total_partner_users,
                    },
                },
                status=200,
            )

        except Exception as e:
            return JsonResponse({"status": "error", "message": str(e)}, status=500)


@method_decorator(csrf_exempt, name="dispatch")
class PartnerListUsersAPI(APIView):
    """
    Partner List Users API.
    Body: token, username (required);
    role (optional filter: partner, partner_manager, partner_staff, partner_customer).
    Returns: list of partner users.
    """

    def post(self, request):
        try:
            user, token, data, error_response = validate_token_and_get_user(request, error_status_code=True)
            if error_response:
                return error_response

            # Check if user has partner role
            partner_roles = ["partner", "partner_manager", "partner_staff"]
            if user.role not in partner_roles:
                return JsonResponse(
                    {"status": "error", "message": "You are not authorized to access this page."},
                    status=403,
                )

            # Filter users by partner-related roles
            all_partner_roles = ["partner", "partner_manager", "partner_staff", "partner_customer"]
            qs = User.objects.filter(role__in=all_partner_roles).order_by("-id")

            # Optional role filter
            role_filter = data.get("role")
            if role_filter:
                if role_filter not in all_partner_roles:
                    return JsonResponse(
                        {
                            "status": "error",
                            "message": f"Invalid role filter. Must be one of: {', '.join(all_partner_roles)}",
                        },
                        status=400,
                    )
                qs = qs.filter(role=role_filter)

            users = [_partner_user_to_dict(u, request) for u in qs]

            return JsonResponse(
                {
                    "status": "success",
                    "users": users,
                    "total_count": len(users),
                },
                status=200,
            )

        except Exception as e:
            return JsonResponse({"status": "error", "message": str(e)}, status=500)


@method_decorator(csrf_exempt, name="dispatch")
class PartnerCreateUserAPI(APIView):
    """
    Partner Create User API.
    Body: token, username, username (for new user), email, password, role (required);
    full_name, phone_number, pincode, district, state, country, place, latitude, longitude (optional).
    Returns: created user data.
    """

    def post(self, request):
        try:
            user, token, data, error_response = validate_token_and_get_user(request, error_status_code=True)
            if error_response:
                return error_response

            # Check if user has partner role
            partner_roles = ["partner", "partner_manager", "partner_staff"]
            if user.role not in partner_roles:
                return JsonResponse(
                    {"status": "error", "message": "You are not authorized to access this page."},
                    status=403,
                )

            # Extract user data
            new_username = data.get("username")
            email = data.get("email")
            password = data.get("password")
            role = data.get("role")
            full_name = data.get("full_name", "").strip()

            if not all([new_username, email, password, role]):
                return JsonResponse(
                    {
                        "status": "error",
                        "message": "username, email, password, and role are required.",
                    },
                    status=400,
                )

            # Validate role - must be one of the partner-related roles
            valid_partner_roles = ["partner", "partner_manager", "partner_staff", "partner_customer"]
            if role not in valid_partner_roles:
                return JsonResponse(
                    {
                        "status": "error",
                        "message": f"Invalid role. Must be one of: {', '.join(valid_partner_roles)}",
                    },
                    status=400,
                )

            # Check if username already exists
            if User.objects.filter(username=new_username).exists():
                return JsonResponse(
                    {"status": "error", "message": "Username already exists."},
                    status=400,
                )

            # Check if email already exists
            if User.objects.filter(email=email).exists():
                return JsonResponse(
                    {"status": "error", "message": "Email already exists."},
                    status=400,
                )

            # Create user
            new_user = User.objects.create_user(
                username=new_username,
                email=email,
                password=password,
                role=role,
                phone_number=data.get("phone_number"),
                pincode=data.get("pincode"),
                district=data.get("district"),
                state=data.get("state"),
                country=data.get("country"),
                place=data.get("place"),
            )

            # Handle full_name - split into first_name and last_name
            if full_name:
                parts = full_name.split(None, 1)
                new_user.first_name = parts[0]
                if len(parts) > 1:
                    new_user.last_name = parts[1]

            # Set location coordinates if provided
            if data.get("latitude") is not None:
                try:
                    latitude = float(data["latitude"])
                    if latitude < -90 or latitude > 90:
                        return JsonResponse(
                            {"status": "error", "message": "latitude must be between -90 and 90."},
                            status=400,
                        )
                    new_user.latitude = latitude
                except (TypeError, ValueError):
                    return JsonResponse(
                        {"status": "error", "message": "latitude must be numeric."},
                        status=400,
                    )

            if data.get("longitude") is not None:
                try:
                    longitude = float(data["longitude"])
                    if longitude < -180 or longitude > 180:
                        return JsonResponse(
                            {"status": "error", "message": "longitude must be between -180 and 180."},
                            status=400,
                        )
                    new_user.longitude = longitude
                except (TypeError, ValueError):
                    return JsonResponse(
                        {"status": "error", "message": "longitude must be numeric."},
                        status=400,
                    )

            # Handle profile picture upload if provided
            if "profile_picture" in request.FILES:
                new_user.profile_picture = request.FILES["profile_picture"]

            new_user.save()

            return JsonResponse(
                {
                    "status": "success",
                    "message": f"User created successfully with role: {role}.",
                    "user": _partner_user_to_dict(new_user, request),
                },
                status=201,
            )

        except Exception as e:
            return JsonResponse({"status": "error", "message": str(e)}, status=500)


@method_decorator(csrf_exempt, name="dispatch")
class PartnerUpdateUserAPI(APIView):
    """
    Partner Update User API.
    Body: token, username, user_id (required);
    email, phone_number, role, full_name, pincode, district, state,
    country, place, latitude, longitude, password, profile_picture (optional).
    Returns: updated user data.
    """

    def post(self, request):
        try:
            user, token, data, error_response = validate_token_and_get_user(request, error_status_code=True)
            if error_response:
                return error_response

            # Check if user has partner role
            partner_roles = ["partner", "partner_manager", "partner_staff"]
            if user.role not in partner_roles:
                return JsonResponse(
                    {"status": "error", "message": "You are not authorized to access this page."},
                    status=403,
                )

            user_id = data.get("user_id")
            if not user_id:
                return JsonResponse(
                    {"status": "error", "message": "user_id is required."},
                    status=400,
                )

            try:
                target_user = User.objects.get(id=user_id)
            except User.DoesNotExist:
                return JsonResponse(
                    {"status": "error", "message": "User not found."},
                    status=404,
                )

            # Validate that the user has a partner-related role
            all_partner_roles = ["partner", "partner_manager", "partner_staff", "partner_customer"]
            if target_user.role not in all_partner_roles:
                return JsonResponse(
                    {
                        "status": "error",
                        "message": "User is not a partner-related user. Only users with partner roles can be updated.",
                    },
                    status=400,
                )

            # Update fields if provided
            if data.get("email") is not None:
                new_email = data["email"]
                # Check if email already exists for another user
                if User.objects.filter(email=new_email).exclude(id=user_id).exists():
                    return JsonResponse(
                        {"status": "error", "message": "Email already exists for another user."},
                        status=400,
                    )
                target_user.email = new_email

            if data.get("phone_number") is not None:
                target_user.phone_number = data["phone_number"] or None

            if data.get("role") is not None:
                new_role = data["role"]
                if new_role not in all_partner_roles:
                    return JsonResponse(
                        {
                            "status": "error",
                            "message": f"Invalid role. Must be one of: {', '.join(all_partner_roles)}",
                        },
                        status=400,
                    )
                target_user.role = new_role

            # Handle full_name
            if data.get("full_name"):
                full_name = data["full_name"].strip()
                if full_name:
                    parts = full_name.split(None, 1)
                    target_user.first_name = parts[0]
                    if len(parts) > 1:
                        target_user.last_name = parts[1]
                    else:
                        target_user.last_name = ""

            if "pincode" in data:
                target_user.pincode = data["pincode"] or None
            if "district" in data:
                target_user.district = data["district"] or None
            if "state" in data:
                target_user.state = data["state"] or None
            if "country" in data:
                target_user.country = data["country"] or None
            if "place" in data:
                target_user.place = data["place"] or None

            if data.get("latitude") is not None:
                try:
                    latitude = float(data["latitude"])
                    if latitude < -90 or latitude > 90:
                        return JsonResponse(
                            {"status": "error", "message": "latitude must be between -90 and 90."},
                            status=400,
                        )
                    target_user.latitude = latitude
                except (TypeError, ValueError):
                    return JsonResponse(
                        {"status": "error", "message": "latitude must be numeric."},
                        status=400,
                    )

            if data.get("longitude") is not None:
                try:
                    longitude = float(data["longitude"])
                    if longitude < -180 or longitude > 180:
                        return JsonResponse(
                            {"status": "error", "message": "longitude must be between -180 and 180."},
                            status=400,
                        )
                    target_user.longitude = longitude
                except (TypeError, ValueError):
                    return JsonResponse(
                        {"status": "error", "message": "longitude must be numeric."},
                        status=400,
                    )

            # Handle profile picture upload if provided
            if "profile_picture" in request.FILES:
                target_user.profile_picture = request.FILES["profile_picture"]

            # Handle password update if provided
            if data.get("password"):
                target_user.set_password(data["password"])

            target_user.save()

            return JsonResponse(
                {
                    "status": "success",
                    "message": "Partner user updated successfully.",
                    "user": _partner_user_to_dict(target_user, request),
                },
                status=200,
            )

        except Exception as e:
            return JsonResponse({"status": "error", "message": str(e)}, status=500)


@method_decorator(csrf_exempt, name="dispatch")
class PartnerDeleteUserAPI(APIView):
    """
    Partner Delete User API.
    Body: token, username, user_id (required).
    Returns: success message.
    """

    def post(self, request):
        try:
            user, token, data, error_response = validate_token_and_get_user(request, error_status_code=True)
            if error_response:
                return error_response

            # Check if user has partner role
            partner_roles = ["partner", "partner_manager", "partner_staff"]
            if user.role not in partner_roles:
                return JsonResponse(
                    {"status": "error", "message": "You are not authorized to access this page."},
                    status=403,
                )

            user_id = data.get("user_id")
            if not user_id:
                return JsonResponse(
                    {"status": "error", "message": "user_id is required."},
                    status=400,
                )

            try:
                target_user = User.objects.get(id=user_id)
            except User.DoesNotExist:
                return JsonResponse(
                    {"status": "error", "message": "User not found."},
                    status=404,
                )

            # Validate that the user has a partner-related role
            all_partner_roles = ["partner", "partner_manager", "partner_staff", "partner_customer"]
            if target_user.role not in all_partner_roles:
                return JsonResponse(
                    {
                        "status": "error",
                        "message": "User is not a partner-related user. Only users with partner roles can be deleted.",
                    },
                    status=400,
                )

            # Prevent deleting yourself
            if target_user.id == user.id:
                return JsonResponse(
                    {"status": "error", "message": "You cannot delete your own account."},
                    status=400,
                )

            username = target_user.username
            target_user.delete()

            return JsonResponse(
                {
                    "status": "success",
                    "message": f"Partner user '{username}' deleted successfully.",
                },
                status=200,
            )

        except Exception as e:
            return JsonResponse({"status": "error", "message": str(e)}, status=500)


@method_decorator(csrf_exempt, name="dispatch")
class LoginAPI(APIView):
    """
    Admin/Staff Login API (accounts).
    Body: username (or email), password (required).
    Returns: token and user details for admin/manager/staff roles.
    """

    def post(self, request):
        try:
            # Parse JSON or form data
            is_multipart = request.content_type and "multipart/form-data" in request.content_type
            if is_multipart:
                data = request.POST.dict()
            else:
                try:
                    data = json.loads(request.body)
                except json.JSONDecodeError:
                    return JsonResponse(
                        {"status": "error", "message": "Invalid JSON"},
                        status=400,
                    )

            username = data.get("username") or data.get("email")
            password = data.get("password")

            if not username or not password:
                return JsonResponse(
                    {"status": "error", "message": "username and password are required."},
                    status=400,
                )

            user = authenticate(request, username=username, password=password)
            if not user:
                return JsonResponse(
                    {"status": "error", "message": "Invalid username or password."},
                    status=401,
                )

            # Only allow admin/manager/staff to use this login
            allowed_roles = ["admin", "manager", "staff"]
            if user.role not in allowed_roles:
                return JsonResponse(
                    {"status": "error", "message": "You are not authorized to access the admin portal."},
                    status=403,
                )

            token, _ = Token.objects.get_or_create(user=user)

            return JsonResponse(
                {
                    "status": "success",
                    "message": "Login successful",
                    "token": token.key,
                    "user": _user_to_dict(user, request),
                },
                status=200,
            )

        except Exception as e:
            return JsonResponse({"status": "error", "message": str(e)}, status=500)


@method_decorator(csrf_exempt, name="dispatch")
class LogoutAPI(APIView):
    """
    Logout API for token-based sessions.
    Body: token, username (required).
    """

    def post(self, request):
        try:
            user, token, data, error_response = validate_token_and_get_user(request, error_status_code=True)
            if error_response:
                return error_response

            logout(request)
            token.delete()

            return JsonResponse(
                {
                    "status": "success",
                    "message": "Logout successful.",
                },
                status=200,
            )

        except Exception as e:
            return JsonResponse({"status": "error", "message": str(e)}, status=500)


@method_decorator(csrf_exempt, name="dispatch")
class UserListAPI(APIView):
    """
    List users (admin / manager / staff only).
    Body: token, username (required); optional role filter.
    """

    def post(self, request):
        try:
            user, token, data, error_response = validate_token_and_get_user(request, error_status_code=True)
            if error_response:
                return error_response

            # Only allow admin/manager/staff to list users
            allowed_roles = ["admin", "manager", "staff"]
            if user.role not in allowed_roles:
                return JsonResponse(
                    {"status": "error", "message": "You are not authorized to list users."},
                    status=403,
                )

            qs = User.objects.all().order_by("-id")
            role_filter = data.get("role")
            if role_filter:
                qs = qs.filter(role=role_filter)

            users = [_user_to_dict(u, request) for u in qs]

            return JsonResponse(
                {
                    "status": "success",
                    "users": users,
                    "total_count": len(users),
                },
                status=200,
            )

        except Exception as e:
            return JsonResponse({"status": "error", "message": str(e)}, status=500)


@method_decorator(csrf_exempt, name="dispatch")
class UserCreateAPI(APIView):
    """
    Create a user (admin / manager / staff only).
    Body: token, username, new_username, email, password, role ('admin'|'manager'|'staff'), phone_number (optional).
    """

    def post(self, request):
        try:
            user, token, data, error_response = validate_token_and_get_user(request, error_status_code=True)
            if error_response:
                return error_response

            allowed_roles = ["admin", "manager", "staff"]
            if user.role not in allowed_roles:
                return JsonResponse(
                    {"status": "error", "message": "You are not authorized to create users."},
                    status=403,
                )

            new_username = data.get("username") or data.get("new_username")
            email = data.get("email")
            password = data.get("password")
            role = data.get("role")

            if not all([new_username, email, password, role]):
                return JsonResponse(
                    {
                        "status": "error",
                        "message": "username, email, password, and role are required.",
                    },
                    status=400,
                )

            valid_roles = ["admin", "manager", "staff"]
            if role not in valid_roles:
                return JsonResponse(
                    {
                        "status": "error",
                        "message": f"Invalid role. Must be one of: {', '.join(valid_roles)}",
                    },
                    status=400,
                )

            if User.objects.filter(username=new_username).exists():
                return JsonResponse(
                    {"status": "error", "message": "Username already exists."},
                    status=400,
                )

            if User.objects.filter(email=email).exists():
                return JsonResponse(
                    {"status": "error", "message": "Email already exists."},
                    status=400,
                )

            new_user = User.objects.create_user(
                username=new_username,
                email=email,
                password=password,
                role=role,
                phone_number=data.get("phone_number"),
            )

            return JsonResponse(
                {
                    "status": "success",
                    "message": f"User created successfully with role: {role}.",
                    "user": _user_to_dict(new_user, request),
                },
                status=201,
            )

        except Exception as e:
            return JsonResponse({"status": "error", "message": str(e)}, status=500)


@method_decorator(csrf_exempt, name="dispatch")
class UserUpdateAPI(APIView):
    """
    Update a user (admin / manager / staff only).
    Body: token, username, user_id (required); email, phone_number, role (optional).
    """

    def post(self, request):
        try:
            user, token, data, error_response = validate_token_and_get_user(request, error_status_code=True)
            if error_response:
                return error_response

            allowed_roles = ["admin", "manager", "staff"]
            if user.role not in allowed_roles:
                return JsonResponse(
                    {"status": "error", "message": "You are not authorized to update users."},
                    status=403,
                )

            user_id = data.get("user_id")
            if not user_id:
                return JsonResponse(
                    {"status": "error", "message": "user_id is required."},
                    status=400,
                )

            try:
                target_user = User.objects.get(id=user_id)
            except User.DoesNotExist:
                return JsonResponse(
                    {"status": "error", "message": "User not found."},
                    status=404,
                )

            if data.get("email") is not None:
                new_email = data["email"]
                if User.objects.filter(email=new_email).exclude(id=user_id).exists():
                    return JsonResponse(
                        {"status": "error", "message": "Email already exists for another user."},
                        status=400,
                    )
                target_user.email = new_email

            if data.get("phone_number") is not None:
                target_user.phone_number = data["phone_number"] or None

            if data.get("role") is not None:
                new_role = data["role"]
                valid_roles = ["admin", "manager", "staff"]
                if new_role not in valid_roles:
                    return JsonResponse(
                        {
                            "status": "error",
                            "message": f"Invalid role. Must be one of: {', '.join(valid_roles)}",
                        },
                        status=400,
                    )
                target_user.role = new_role

            target_user.save()

            return JsonResponse(
                {
                    "status": "success",
                    "message": "User updated successfully.",
                    "user": _user_to_dict(target_user, request),
                },
                status=200,
            )

        except Exception as e:
            return JsonResponse({"status": "error", "message": str(e)}, status=500)


@method_decorator(csrf_exempt, name="dispatch")
class UserDeleteAPI(APIView):
    """
    Delete a user (admin / manager / staff only).
    Body: token, username, user_id (required).
    """

    def post(self, request):
        try:
            user, token, data, error_response = validate_token_and_get_user(request, error_status_code=True)
            if error_response:
                return error_response

            allowed_roles = ["admin", "manager", "staff"]
            if user.role not in allowed_roles:
                return JsonResponse(
                    {"status": "error", "message": "You are not authorized to delete users."},
                    status=403,
                )

            user_id = data.get("user_id")
            if not user_id:
                return JsonResponse(
                    {"status": "error", "message": "user_id is required."},
                    status=400,
                )

            try:
                target_user = User.objects.get(id=user_id)
            except User.DoesNotExist:
                return JsonResponse(
                    {"status": "error", "message": "User not found."},
                    status=404,
                )

            if target_user.id == user.id:
                return JsonResponse(
                    {"status": "error", "message": "You cannot delete your own account."},
                    status=400,
                )

            username = target_user.username
            target_user.delete()

            return JsonResponse(
                {
                    "status": "success",
                    "message": f"User '{username}' deleted successfully.",
                },
                status=200,
            )

        except Exception as e:
            return JsonResponse({"status": "error", "message": str(e)}, status=500)