from typing import Type, TypeVar, Generic, List, Optional, Any, Dict
from sqlalchemy.orm import Session
from sqlalchemy.ext.declarative import DeclarativeMeta

ModelType = TypeVar("ModelType")

class BaseService(Generic[ModelType]):
    def __init__(self, model: Type[ModelType]):
        self.model = model

    def create(self, db: Session, obj_data: Dict[str, Any]) -> ModelType:
        """创建记录"""
        db_obj = self.model(**obj_data)
        db.add(db_obj)
        db.commit()
        db.refresh(db_obj)
        return db_obj

    def get_by_id(self, db: Session, obj_id: int) -> Optional[ModelType]:
        """根据ID获取记录"""
        return db.query(self.model).filter(self.model.id == obj_id).first()

    def get_all(self, db: Session, skip: int = 0, limit: int = 100) -> List[ModelType]:
        """获取所有记录"""
        return db.query(self.model).offset(skip).limit(limit).all()

    def update(self, db: Session, obj_id: int, update_data: Dict[str, Any]) -> Optional[ModelType]:
        """更新记录"""
        db_obj = self.get_by_id(db, obj_id)
        if db_obj:
            for field, value in update_data.items():
                if hasattr(db_obj, field):
                    setattr(db_obj, field, value)
            db.commit()
            db.refresh(db_obj)
            return db_obj
        return None

    def delete(self, db: Session, obj_id: int) -> bool:
        """删除记录"""
        db_obj = self.get_by_id(db, obj_id)
        if db_obj:
            db.delete(db_obj)
            db.commit()
            return True
        return False

    def get_by_field(self, db: Session, field_name: str, field_value: Any) -> List[ModelType]:
        """根据字段值查询记录"""
        if hasattr(self.model, field_name):
            field = getattr(self.model, field_name)
            return db.query(self.model).filter(field == field_value).all()
        return []

    def search_by_conditions(self, db: Session, conditions: Dict[str, Any]) -> List[ModelType]:
        """根据多个条件搜索记录"""
        query = db.query(self.model)
        for field_name, field_value in conditions.items():
            if hasattr(self.model, field_name) and field_value is not None:
                field = getattr(self.model, field_name)
                if isinstance(field_value, str):
                    query = query.filter(field.like(f"%{field_value}%"))
                else:
                    query = query.filter(field == field_value)
        return query.all()