from rest_framework.exceptions import ValidationError
from django.db import transaction
from .models import Vehicle, WorkOrder, VehicleServiceRecord
from decimal import Decimal


class VehicleService:
    @staticmethod
    def create_vehicle(data: dict) -> Vehicle:
        vehicle = Vehicle(**data)
        try:
            vehicle.full_clean()
        except Exception as e:
            raise ValidationError({"detail": str(e)})

        vehicle.save()
        return vehicle

    @staticmethod
    def update_vehicle(instance: Vehicle, data: dict) -> Vehicle:
        for k, v in data.items():
            setattr(instance, k, v)
        try:
            instance.full_clean()
        except Exception as e:
            raise ValidationError({"detail": str(e)})
        instance.save()
        return instance

    @staticmethod
    def create_work_order(data: dict) -> WorkOrder:
        # expecting creator in data
        wo = WorkOrder(**data)
        try:
            wo.full_clean()
        except Exception as e:
            raise ValidationError({"detail": str(e)})

        # save will handle updating vehicle mileage if end_mileage set
        with transaction.atomic():
            wo.save()
        return wo

    @staticmethod
    def update_work_order(instance: WorkOrder, data: dict) -> WorkOrder:
        for k, v in data.items():
            setattr(instance, k, v)
        try:
            instance.full_clean()
        except Exception as e:
            raise ValidationError({"detail": str(e)})
        with transaction.atomic():
            instance.save()
        return instance

    @staticmethod
    def create_service_record(data: dict) -> VehicleServiceRecord:
        rec = VehicleServiceRecord(**data)
        try:
            rec.full_clean()
        except Exception as e:
            raise ValidationError({"detail": str(e)})
        with transaction.atomic():
            rec.save()
            # optionally update vehicle.current_mileage if rec.mileage > current
            v = rec.vehicle
            if rec.mileage and rec.mileage > (v.current_mileage or 0):
                v.current_mileage = rec.mileage
                v.save()
        return rec