from typing import Type, TypeVar, Generic, List, Optional, Any
from sqlalchemy.orm import Session
from app.db.database import Base
from app.services.service_registry import ServiceRegistry

T = TypeVar('T')

class BaseService(Generic[T]):
    def __init__(self, model: Type[T]):
        self.model = model
        # Register the service instance
        ServiceRegistry.register(self.__class__.__name__, self)

    def get(self, db: Session, id: int) -> Optional[T]:
        return db.query(self.model).filter(self.model.id == id).first()

    def get_all(self, db: Session, skip: int = 0, limit: int = 100) -> List[T]:
        return db.query(self.model).offset(skip).limit(limit).all()

    def create(self, db: Session, obj_in: dict) -> T:
        db_obj = self.model(**obj_in)
        db.add(db_obj)
        db.commit()
        db.refresh(db_obj)
        return db_obj

    def update(self, db: Session, db_obj: T, obj_in: dict) -> T:
        for field in obj_in:
            if hasattr(db_obj, field):
                setattr(db_obj, field, obj_in[field])
        db.add(db_obj)
        db.commit()
        db.refresh(db_obj)
        return db_obj

    def delete(self, db: Session, id: int) -> bool:
        obj = db.query(self.model).filter(self.model.id == id).first()
        if obj:
            db.delete(obj)
            db.commit()
            return True
        return False

    def get_service(self, service_name: str) -> Any:
        return ServiceRegistry.get(service_name)