"""streaming.py 三层活性看门狗测试(移植自 VT adapters/streaming.py,语义零改动)。"""

import asyncio

import pytest

from polygateway.streaming import StreamLivenessTimeout, stream_with_liveness_timeouts


async def _emit(items, *, delay_s=0.0, first_delay_s=None):
    """可控节奏的假流;first_delay_s 单独控制首项延迟。"""
    for i, item in enumerate(items):
        wait = first_delay_s if (i == 0 and first_delay_s is not None) else delay_s
        if wait:
            await asyncio.sleep(wait)
        yield item


async def _collect(agen):
    return [item async for item in agen]


class TestPassthrough:
    async def test_items_pass_through_in_order(self):
        wrapped = stream_with_liveness_timeouts(
            _emit(["a", "b", "c"]), ttft_s=1.0, inter_token_s=1.0, total_s=5.0
        )
        assert await _collect(wrapped) == ["a", "b", "c"]

    async def test_empty_stream_ends_cleanly(self):
        wrapped = stream_with_liveness_timeouts(
            _emit([]), ttft_s=1.0, inter_token_s=1.0, total_s=5.0
        )
        assert await _collect(wrapped) == []


class TestThreeLayers:
    async def test_ttft_timeout(self):
        wrapped = stream_with_liveness_timeouts(
            _emit(["a"], first_delay_s=0.2), ttft_s=0.05, inter_token_s=1.0, total_s=5.0
        )
        with pytest.raises(StreamLivenessTimeout) as ei:
            await _collect(wrapped)
        assert ei.value.kind == "ttft"
        assert ei.value.first_token_seen is False

    async def test_inter_token_timeout(self):
        wrapped = stream_with_liveness_timeouts(
            _emit(["a", "b"], delay_s=0.2, first_delay_s=0.0),
            ttft_s=1.0,
            inter_token_s=0.05,
            total_s=5.0,
        )
        with pytest.raises(StreamLivenessTimeout) as ei:
            await _collect(wrapped)
        assert ei.value.kind == "inter_token"
        assert ei.value.first_token_seen is True

    async def test_total_timeout(self):
        # 每项都快,但项数多到总时长超限 → 判 total 而非 inter_token
        wrapped = stream_with_liveness_timeouts(
            _emit(list(range(100)), delay_s=0.02), ttft_s=1.0, inter_token_s=1.0, total_s=0.1
        )
        with pytest.raises(StreamLivenessTimeout) as ei:
            await _collect(wrapped)
        assert ei.value.kind == "total"


class TestForeignTimeoutAndCleanup:
    async def test_upstream_timeout_error_not_reclassified(self):
        """上游自抛的 TimeoutError 不得被误判为本层活性超时。"""

        async def bad_stream():
            raise TimeoutError("upstream own timeout")
            yield  # pragma: no cover

        wrapped = stream_with_liveness_timeouts(
            bad_stream(), ttft_s=1.0, inter_token_s=1.0, total_s=5.0
        )
        with pytest.raises(TimeoutError) as ei:
            await _collect(wrapped)
        assert not isinstance(ei.value, StreamLivenessTimeout)

    async def test_underlying_iterator_closed_on_abandon(self):
        closed = asyncio.Event()

        async def tracked():
            try:
                for i in range(100):
                    await asyncio.sleep(0.01)
                    yield i
            finally:
                closed.set()

        wrapped = stream_with_liveness_timeouts(
            tracked(), ttft_s=1.0, inter_token_s=1.0, total_s=5.0
        )
        assert (await wrapped.__anext__()) == 0
        await wrapped.aclose()  # 消费方提前放弃 → finally 关闭底层迭代器
        assert closed.is_set()

    async def test_cancellation_propagates(self):
        wrapped = stream_with_liveness_timeouts(
            _emit(["a"], first_delay_s=10.0), ttft_s=30.0, inter_token_s=30.0, total_s=60.0
        )
        task = asyncio.ensure_future(_collect(wrapped))
        await asyncio.sleep(0.05)
        task.cancel()
        with pytest.raises(asyncio.CancelledError):
            await task