"""
异步友好的 never_cache 类装饰器
================================
替代 `@method_decorator(never_cache, name='dispatch')`。

背景：@method_decorator 生成同步包装器，在 adrf 的 async dispatch 返回的协程上
调用 add_never_cache_headers 会抛 AttributeError（'coroutine' object has no
attribute 'has_header'）。本装饰器兼容同步/异步 dispatch，语义与 never_cache 一致。

用法（作为类装饰器）：
    @async_never_cache_dispatch
    class WalletBalanceAPIView(APIView):
        ...
"""
import asyncio

from django.utils.cache import add_never_cache_headers


def async_never_cache_dispatch(cls):
    orig_dispatch = cls.dispatch

    async def dispatch(self, request, *args, **kwargs):
        response = orig_dispatch(self, request, *args, **kwargs)
        if asyncio.iscoroutine(response):
            response = await response
        if response is not None and hasattr(response, "has_header"):
            add_never_cache_headers(response)
        return response

    cls.dispatch = dispatch
    return cls