from typing import Any, Dict, List, Optional, Union, ClassVar
from pydantic import BaseModel, Field
from datetime import datetime

class APIResponseModel(BaseModel):
    """API响应基础模型"""
    code: int = Field(200, description="业务状态码")
    message: str = Field("操作成功", description="响应消息")
    data: Optional[Any] = Field(None, description="响应数据")
    
    class Config:
        """模型配置"""
        arbitrary_types_allowed = True
        json_encoders = {
            datetime: lambda dt: dt.isoformat()
        }

class PaginatedResponseModel(BaseModel):
    """分页响应模型"""
    items: List[Any] = Field(..., description="数据项列表")
    total: int = Field(..., description="总数据量")
    page: int = Field(1, description="当前页码")
    size: int = Field(10, description="每页数据量")
    
    class Config:
        """模型配置"""
        arbitrary_types_allowed = True