"""统一响应格式"""
from typing import Any, Generic, Optional, TypeVar, List
from pydantic import BaseModel, Field

T = TypeVar("T")


class ResponseModel(BaseModel, Generic[T]):
    """通用响应格式"""
    code: int = 200
    message: str = "success"
    data: Optional[T] = None
    timestamp: int = 0

    class Config:
        from_attributes = True


class PageResult(BaseModel, Generic[T]):
    """分页响应格式"""
    items: List[T] = Field(default_factory=list, serialization_alias="list")
    total: int = 0
    page: int = 1
    pageSize: int = 10
    totalPages: int = 0


def success_response(data: Any = None, message: str = "success") -> dict:
    """成功响应"""
    from datetime import datetime
    return {
        "code": 200,
        "message": message,
        "data": data,
        "timestamp": int(datetime.now().timestamp() * 1000)
    }


def format_api_error_message(exc: Exception, *, fallback: str = "操作失败") -> str:
    """将 HTTP/SQLAlchemy 等异常转为可展示的错误文案（避免 str([]) 空列表）。"""
    if isinstance(exc, PermissionError):
        return str(exc) or fallback
    status_code = getattr(exc, "status_code", None)
    if status_code is not None:
        detail = getattr(exc, "detail", None)
        if isinstance(detail, str) and detail.strip():
            return detail
        if detail not in (None, "", []):
            return str(detail)
    msg = str(exc).strip()
    if msg and msg != "[]":
        return msg
    return fallback


def error_response(code: int = 400, message: str = "error", data: Any = None) -> dict:
    """错误响应"""
    from datetime import datetime
    return {
        "code": code,
        "message": message,
        "data": data,
        "timestamp": int(datetime.now().timestamp() * 1000)
    }