from typing import Any, Dict, Generic, List, Optional, Type, TypeVar, Union
from fastapi.encoders import jsonable_encoder
from pydantic import BaseModel
from sqlalchemy.orm import Session
from sqlalchemy import Column
from mooc.db.database import Base

ModelType = TypeVar("ModelType", bound="Base")
CreateSchemaType = TypeVar("CreateSchemaType", bound=BaseModel)
UpdateSchemaType = TypeVar("UpdateSchemaType", bound=BaseModel)

class CRUDBase(Generic[ModelType, CreateSchemaType, UpdateSchemaType]):
    def __init__(self, model: Type[ModelType]):
        """
        CRUD base class
        Args:
            model: SQLAlchemy模型类
        """
        self.model = model

    def get(self, db: Session, id: Any) -> Optional[ModelType]:
        """通过主键获取记录"""
        # 检查模型是否有id字段，如果没有则使用acid
        if hasattr(self.model, 'id'):
            return db.query(self.model).filter(self.model.id == id).first()
        return db.query(self.model).filter(self.model.acid == id).first()

    def get_by_field(
        self, 
        db: Session, 
        field: str, 
        value: Any
    ) -> Optional[ModelType]:
        """
        通过任意字段获取单条记录
        Args:
            db: 数据库会话
            field: 字段名
            value: 字段值
        """
        return db.query(self.model).filter(getattr(self.model, field) == value).first()
        
    def get_by_fields(
        self,
        db: Session,
        filters: Dict[str, Any]
    ) -> Optional[ModelType]:
        """
        通过多个字段AND条件查询获取单条记录
        
        Args:
            db: 数据库会话
            filters: 字段名和字段值的字典，如 {"field1": value1, "field2": value2}
        """
        query = db.query(self.model)
        for field, value in filters.items():
            query = query.filter(getattr(self.model, field) == value)
        return query.first()

    def get_multi_by_fields(
        self,
        db: Session,
        filters: Dict[str, Any],
        *,
        skip: int = 0,
        limit: int = 100
    ) -> List[ModelType]:
        """
        通过多个字段AND条件查询获取多条记录
        
        Args:
            db: 数据库会话
            filters: 字段名和字段值的字典，如 {"field1": value1, "field2": value2}
            skip: 跳过记录数
            limit: 返回记录数限制
        """
        query = db.query(self.model)
        for field, value in filters.items():
            query = query.filter(getattr(self.model, field) == value)
        return query.offset(skip).limit(limit).all()

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

    def create(self, db: Session, *, obj_in: CreateSchemaType) -> ModelType:
        obj_in_data = jsonable_encoder(obj_in)
        db_obj = self.model(**obj_in_data)
        db.add(db_obj)
        try:
            db.commit()
            db.refresh(db_obj)
        except Exception as e:
            db.rollback()
            raise e
        return db_obj

    def update(
        self,
        db: Session,
        *,
        db_obj: ModelType,
        obj_in: Union[UpdateSchemaType, Dict[str, Any]]
    ) -> ModelType:
        obj_data = jsonable_encoder(db_obj)
        if isinstance(obj_in, dict):
            update_data = obj_in
        else:
            update_data = obj_in.dict(exclude_unset=True)
        for field in obj_data:
            if field in update_data:
                setattr(db_obj, field, update_data[field])
        db.add(db_obj)
        try:
            db.commit()
            db.refresh(db_obj)
        except Exception as e:
            db.rollback()
            raise e
        return db_obj

    def delete(self, db: Session, *, id: int) -> ModelType:
        obj = db.query(self.model).get(id)
        if obj:
            try:
                db.delete(obj)
                db.commit()
            except Exception as e:
                db.rollback()
                raise e
        return obj