"""投顾 Agent 的统一超时与降级执行器。"""
from __future__ import annotations

import asyncio
import inspect
import logging
from dataclasses import dataclass
from typing import Awaitable, Callable, TypeVar

from utils.exceptions import ApiError


T = TypeVar("T")
logger = logging.getLogger("advisor_agent.fallback")


@dataclass(frozen=True)
class FallbackResult:
    value: object
    degraded: bool
    code: int | None = None


async def call_with_fallback(
    primary: Callable[[], Awaitable[T]],
    secondary: Callable[[], Awaitable[T]] | None,
    *,
    timeout: float,
    degraded_code: int,
    on_degraded: Callable[[Exception], None] | None = None,
) -> FallbackResult:
    try:
        return FallbackResult(
            value=await asyncio.wait_for(primary(), timeout=timeout),
            degraded=False,
        )
    except Exception as primary_error:
        logger.warning("advisor dependency degraded; using fallback", exc_info=primary_error)
        if on_degraded is not None:
            try:
                callback_result = on_degraded(primary_error)
                if inspect.isawaitable(callback_result):
                    await callback_result
            except Exception:
                logger.warning("advisor degradation audit callback failed", exc_info=True)
        if secondary is None:
            raise ApiError(degraded_code, "Agent核心服务调用失败") from primary_error
        try:
            value = await asyncio.wait_for(secondary(), timeout=timeout)
        except Exception as secondary_error:
            raise ApiError(degraded_code, "Agent降级服务调用失败") from secondary_error
        return FallbackResult(value=value, degraded=True, code=degraded_code)