"""定义统一 API 响应结构"""

from typing import Any, Generic, TypeVar

from pydantic import BaseModel, field_validator

DataT = TypeVar("DataT")
ResponseData = BaseModel | dict[str, Any] | list[Any] | None


class ApiResponse(BaseModel, Generic[DataT]):
    code: int = 0
    data: DataT | None = None
    msg: str = ""

    @field_validator("data")
    @classmethod
    def validate_data_shape(cls, value: DataT | None) -> DataT | None:
        """限制响应数据为对象、数组或空值"""
        if value is not None and not isinstance(value, (BaseModel, dict, list)):
            raise ValueError("响应 data 必须为对象、数组或 null")
        return value


def success_response(
    data: DataT | None = None,
    msg: str = "",
) -> ApiResponse[DataT | dict[str, Any]]:
    """构造统一成功响应"""
    response_data: DataT | dict[str, Any] = {} if data is None else data
    return ApiResponse(code=0, data=response_data, msg=msg)


def error_content(
    code: int, msg: str = "请求失败"
) -> dict[str, ResponseData | int | str]:
    """构造统一失败响应内容"""
    return ApiResponse[ResponseData](code=code, data=None, msg=msg).model_dump(
        mode="json"
    )