# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project

"""Unit tests for AR EngineCore vs diffusion worker pause/sleep routing."""

from __future__ import annotations

import asyncio
from types import SimpleNamespace
from unittest.mock import AsyncMock, call

import pytest
from vllm.renderers import BaseRenderer
from vllm.v1.engine.input_processor import InputProcessor

from vllm_omni.diffusion.data import CuMemTag, OmniACK
from vllm_omni.entrypoints.async_omni import CACHE_RESET_TIMEOUT_S, AsyncOmni

pytestmark = [pytest.mark.core_model]


def _make_omni(*, stage_types: list[str]) -> AsyncOmni:
    omni = object.__new__(AsyncOmni)
    omni._pause_cond = asyncio.Condition()
    omni._paused = False
    omni._admitting = 0
    omni._hold_admission_until_resume = False
    omni._paused_stage_ids = set()
    omni._sleeping_tags = set()
    omni._stage_sleeping_tags = {}
    omni._level2_sleeping = False
    omni.event_resolver = SimpleNamespace(watch_task=lambda *a, **k: None, resolve=AsyncMock())
    omni._final_output_handler = lambda: None
    omni._clear_frontend_mm_cache = AsyncMock()

    stage_configs = [SimpleNamespace(stage_type=stage_type) for stage_type in stage_types]
    omni.engine = SimpleNamespace(
        stage_configs=stage_configs,
        stage_vllm_configs=[None] * len(stage_types),
        collective_rpc_async=AsyncMock(return_value=[True]),
    )
    omni.collective_rpc = AsyncMock(return_value=[True])
    return omni


@pytest.mark.cpu
def test_reset_mm_cache_routes_through_renderer(mocker):
    async def run() -> None:
        omni = _make_omni(stage_types=["llm"])
        del omni._clear_frontend_mm_cache
        renderer = mocker.create_autospec(BaseRenderer, instance=True)
        input_processor = mocker.create_autospec(InputProcessor, instance=True)
        input_processor.renderer = renderer
        omni.input_processor = input_processor

        await omni.reset_mm_cache()

        renderer.clear_mm_cache_async.assert_awaited_once_with()

    asyncio.run(run())


@pytest.mark.cpu
def test_split_stage_ids_by_type():
    omni = _make_omni(stage_types=["llm", "diffusion", "llm"])
    ar_ids, diff_ids = omni._split_stage_ids_by_type()
    assert ar_ids == [0, 2]
    assert diff_ids == [1]


@pytest.mark.cpu
def test_split_stage_ids_by_type_rejects_out_of_range():
    omni = _make_omni(stage_types=["llm", "diffusion"])
    with pytest.raises(ValueError, match=r"Invalid stage_ids \[2\].*0\.\.1"):
        omni._split_stage_ids_by_type([0, 2])
    with pytest.raises(ValueError, match=r"Invalid stage_ids \[-1\]"):
        omni._split_stage_ids_by_type([-1])


@pytest.mark.cpu
def test_pause_generation_routes_ar_via_collective_rpc():
    async def run() -> None:
        omni = _make_omni(stage_types=["llm", "diffusion"])
        omni.reset_prefix_cache = AsyncMock(return_value=True)
        omni.reset_mm_cache = AsyncMock()
        omni.reset_encoder_cache = AsyncMock()

        await omni.pause_generation(mode="abort", clear_cache=True)

        assert omni._paused is True
        assert omni._hold_admission_until_resume is True
        omni.collective_rpc.assert_awaited_once_with(
            method="pause_scheduler",
            args=(),
            kwargs={"mode": "abort", "clear_cache": True},
            stage_ids=[0],
        )

    asyncio.run(run())


@pytest.mark.cpu
def test_pause_generation_still_rpcs_when_already_paused():
    async def run() -> None:
        omni = _make_omni(stage_types=["llm", "diffusion"])
        omni.reset_prefix_cache = AsyncMock(return_value=True)
        omni.reset_mm_cache = AsyncMock()
        omni.reset_encoder_cache = AsyncMock()
        omni._paused = True

        await omni.pause_generation(mode="abort", clear_cache=True, stage_ids=[0])

        omni.collective_rpc.assert_awaited_once_with(
            method="pause_scheduler",
            args=(),
            kwargs={"mode": "abort", "clear_cache": True},
            stage_ids=[0],
        )
        omni.reset_prefix_cache.assert_not_awaited()
        omni.reset_mm_cache.assert_not_awaited()
        omni.reset_encoder_cache.assert_not_awaited()
        omni._clear_frontend_mm_cache.assert_awaited_once_with()

    asyncio.run(run())


@pytest.mark.cpu
def test_resume_generation_resumes_ar_then_clears_frontend_pause():
    async def run() -> None:
        omni = _make_omni(stage_types=["llm", "diffusion"])
        omni._paused = True

        await omni.resume_generation()

        omni.collective_rpc.assert_awaited_once_with(
            method="resume_scheduler",
            args=(),
            kwargs=None,
            stage_ids=[0],
        )
        assert omni._paused is False
        assert omni._hold_admission_until_resume is False

    asyncio.run(run())


@pytest.mark.cpu
def test_reset_prefix_cache_forwards_to_ar_stages():
    async def run() -> None:
        omni = _make_omni(stage_types=["llm", "diffusion"])

        result = await omni.reset_prefix_cache(reset_running_requests=True, reset_connector=True)

        assert result is True
        omni.collective_rpc.assert_awaited_once_with(
            method="reset_prefix_cache",
            args=(True, True),
            kwargs=None,
            stage_ids=[0],
            timeout=CACHE_RESET_TIMEOUT_S,
        )

    asyncio.run(run())


@pytest.mark.cpu
def test_reset_prefix_cache_diffusion_only_skips_rpc():
    async def run() -> None:
        omni = _make_omni(stage_types=["diffusion"])

        result = await omni.reset_prefix_cache()

        assert result is True
        omni.collective_rpc.assert_not_awaited()

    asyncio.run(run())


@pytest.mark.cpu
def test_reset_encoder_cache_forwards_to_ar_stages():
    async def run() -> None:
        omni = _make_omni(stage_types=["llm", "diffusion"])

        await omni.reset_encoder_cache()

        omni.collective_rpc.assert_awaited_once_with(
            method="reset_encoder_cache",
            args=(),
            kwargs=None,
            stage_ids=[0],
            timeout=CACHE_RESET_TIMEOUT_S,
        )

    asyncio.run(run())


@pytest.mark.cpu
def test_release_kv_memory_requires_pause_and_wakes_only_ar_kv_allocations():
    async def run() -> None:
        omni = _make_omni(stage_types=["llm", "diffusion", "llm"])
        with pytest.raises(RuntimeError, match="completed pause"):
            await omni.release_kv_cache_memory()
        omni.collective_rpc.assert_not_awaited()

        omni._paused = True
        await omni.release_kv_cache_memory()
        omni._clear_frontend_mm_cache.assert_awaited_once_with()
        omni.collective_rpc.assert_awaited_once_with(
            method="release_kv_cache_memory",
            args=(),
            kwargs=None,
            stage_ids=[0, 2],
            timeout=CACHE_RESET_TIMEOUT_S,
        )
        assert omni._stage_sleeping_tags == {0: {"kv_cache"}, 2: {"kv_cache"}}
        assert not omni._level2_sleeping

        omni.collective_rpc.reset_mock()
        await omni.wake_up(stage_ids=[0, 2], tags=["kv_cache"])
        omni.collective_rpc.assert_awaited_once_with(
            method="wake_up", args=(), kwargs={"tags": ["kv_cache"]}, stage_ids=[0, 2]
        )
        assert not omni._sleeping_tags
        assert omni._paused

    asyncio.run(run())


@pytest.mark.cpu
def test_release_kv_memory_skips_diffusion_and_reports_engine_failures():
    async def run() -> None:
        diffusion = _make_omni(stage_types=["diffusion"])
        await diffusion.release_kv_cache_memory()
        diffusion.collective_rpc.assert_not_awaited()
        assert not diffusion._paused

        omni = _make_omni(stage_types=["llm"])
        omni._paused = True
        omni.collective_rpc.return_value = [{"supported": False, "error": "requires all executor memory resident"}]
        with pytest.raises(RuntimeError, match="all executor memory resident"):
            await omni.release_kv_cache_memory()
        assert not omni._sleeping_tags

    asyncio.run(run())


@pytest.mark.cpu
def test_reset_mm_cache_clears_frontend_then_forwards_to_ar_stages():
    async def run() -> None:
        omni = _make_omni(stage_types=["llm", "diffusion"])
        calls = []
        renderer = SimpleNamespace(clear_mm_cache_async=AsyncMock(side_effect=lambda: calls.append("frontend")))
        omni.input_processor = SimpleNamespace(renderer=renderer)
        del omni._clear_frontend_mm_cache

        async def rpc(**kwargs):
            calls.append("engine")
            return [None]

        omni.collective_rpc.side_effect = rpc
        await omni.reset_mm_cache()

        assert calls == ["frontend", "engine"]
        omni.collective_rpc.assert_awaited_once_with(
            method="reset_mm_cache",
            args=(),
            kwargs=None,
            stage_ids=[0],
            timeout=CACHE_RESET_TIMEOUT_S,
        )

    asyncio.run(run())


@pytest.mark.cpu
def test_sleep_routes_ar_via_collective_rpc_and_diffusion_to_worker_rpc():
    async def run() -> None:
        omni = _make_omni(stage_types=["llm", "diffusion"])
        diffusion_ack = OmniACK(task_id="diff", status="SUCCESS", stage_id=1, rank=0)
        omni._sleep_diffusion = AsyncMock(return_value=[diffusion_ack])

        acks = await omni.sleep(stage_ids=[0, 1], level=1, mode="abort")

        omni.collective_rpc.assert_awaited_once_with(
            method="sleep",
            args=(1, "abort"),
            kwargs=None,
            stage_ids=[0],
        )
        omni._sleep_diffusion.assert_awaited_once_with([1], 1)
        assert {ack.stage_id for ack in acks} == {0, 1}
        assert any(ack.metadata.get("path") == "engine_core" for ack in acks if ack.stage_id == 0)
        assert CuMemTag.WEIGHTS.value in omni._sleeping_tags
        assert CuMemTag.KV_CACHE.value in omni._sleeping_tags
        # Sleep gates frontend admission for the trainer resume contract.
        assert omni._paused is True
        assert omni._hold_admission_until_resume is True

    asyncio.run(run())


@pytest.mark.cpu
def test_sleep_blocks_admission_before_engine_core_rpc():
    """Problem 3: _paused must be set before awaiting sleep RPC."""

    async def run() -> None:
        omni = _make_omni(stage_types=["llm"])
        paused_at_rpc: list[bool] = []

        async def rpc_side_effect(**kwargs):
            if kwargs.get("method") == "sleep":
                paused_at_rpc.append(omni._paused)
            return [True]

        omni.collective_rpc = AsyncMock(side_effect=rpc_side_effect)

        assert omni._paused is False
        await omni.sleep(level=1, mode="abort")

        assert paused_at_rpc == [True]
        assert omni._paused is True
        assert omni._hold_admission_until_resume is True
        # Sleep must not also call pause_scheduler (EngineCore.sleep pauses).
        assert all(c.kwargs.get("method") != "pause_scheduler" for c in omni.collective_rpc.await_args_list)

    asyncio.run(run())


@pytest.mark.cpu
def test_sleep_waits_for_in_flight_generate_admission():
    """Sleep must not offload while generate() is still in add_request."""

    async def run() -> None:
        omni = _make_omni(stage_types=["llm"])
        omni._admitting = 1
        rpc_started = asyncio.Event()

        async def rpc_side_effect(**kwargs):
            if kwargs.get("method") == "sleep":
                rpc_started.set()
            return [True]

        omni.collective_rpc = AsyncMock(side_effect=rpc_side_effect)
        sleep_task = asyncio.create_task(omni.sleep(level=1, mode="abort"))
        await asyncio.sleep(0.05)
        assert not sleep_task.done()
        assert not rpc_started.is_set()
        await omni._release_generate_admission()
        await asyncio.wait_for(sleep_task, timeout=1)
        assert rpc_started.is_set()
        assert omni._admitting == 0

    asyncio.run(run())


@pytest.mark.cpu
def test_wake_up_routes_ar_via_collective_rpc_and_diffusion_to_worker_rpc():
    async def run() -> None:
        omni = _make_omni(stage_types=["llm", "diffusion"])
        omni._paused = True
        omni._hold_admission_until_resume = True
        omni._sleeping_tags = {CuMemTag.WEIGHTS.value, CuMemTag.KV_CACHE.value}
        diffusion_ack = OmniACK(task_id="diff", status="SUCCESS", stage_id=1, rank=0)
        omni._wake_diffusion = AsyncMock(return_value=[diffusion_ack])

        acks = await omni.wake_up(stage_ids=[0, 1])

        omni.collective_rpc.assert_awaited_once()
        wake_kwargs = omni.collective_rpc.await_args.kwargs
        assert wake_kwargs["method"] == "wake_up"
        assert wake_kwargs["stage_ids"] == [0]
        assert set(wake_kwargs["kwargs"]["tags"]) == {
            CuMemTag.WEIGHTS.value,
            CuMemTag.KV_CACHE.value,
        }
        omni._wake_diffusion.assert_awaited_once()
        assert {ack.stage_id for ack in acks} == {0, 1}
        assert not omni._sleeping_tags
        # Mixed/AR wake restores memory but does not resume frontend admission.
        assert omni._paused is True
        assert omni._hold_admission_until_resume is True

    asyncio.run(run())


@pytest.mark.cpu
def test_wake_up_does_not_resume_frontend_admission():
    async def run() -> None:
        omni = _make_omni(stage_types=["llm"])
        await omni.sleep(level=1, mode="abort")
        assert omni._paused is True
        assert omni._hold_admission_until_resume is True

        await omni.wake_up()

        assert omni._paused is True
        assert omni._hold_admission_until_resume is True
        assert not omni._sleeping_tags
        # Explicit resume is required after AR sleep/wake.
        await omni.resume_generation()
        assert omni._paused is False
        assert omni._hold_admission_until_resume is False

    asyncio.run(run())


@pytest.mark.cpu
def test_sleep_level1_wake_without_tags_clears_all_sleeping_tags():
    """sleep(level=1) tracks WEIGHTS+KV; untagged wake_up must clear both."""

    async def run() -> None:
        omni = _make_omni(stage_types=["llm"])

        await omni.sleep(level=1, mode="abort")
        assert CuMemTag.WEIGHTS.value in omni._sleeping_tags
        assert CuMemTag.KV_CACHE.value in omni._sleeping_tags

        await omni.wake_up()
        assert not omni._sleeping_tags
        assert omni._paused is True
        assert omni._hold_admission_until_resume is True

    asyncio.run(run())


@pytest.mark.cpu
def test_sleep_diffusion_only_skips_engine_core_collective_rpc():
    async def run() -> None:
        omni = _make_omni(stage_types=["diffusion"])
        omni._sleep_diffusion = AsyncMock(return_value=[OmniACK(task_id="d", status="SUCCESS", stage_id=0, rank=0)])

        await omni.sleep(level=1)

        # AR EngineCore sleep path must not run for diffusion-only.
        assert call(method="sleep", args=(1, "abort"), kwargs=None, stage_ids=[0]) not in (
            omni.collective_rpc.await_args_list
        )
        omni._sleep_diffusion.assert_awaited_once_with([0], 1)
        assert omni._paused is True
        assert omni._hold_admission_until_resume is False

    asyncio.run(run())


@pytest.mark.cpu
def test_streaming_wait_for_first_chunk_does_not_block_sleep():
    """Waiting for the next client chunk must not hold an admission slot."""

    async def run() -> None:
        omni = _make_omni(stage_types=["llm"])
        rpc_started = asyncio.Event()
        first_chunk = asyncio.Event()

        async def rpc_side_effect(**kwargs):
            if kwargs.get("method") == "sleep":
                rpc_started.set()
            return [True]

        omni.collective_rpc = AsyncMock(side_effect=rpc_side_effect)

        async def wait_then_submit() -> None:
            await first_chunk.wait()
            await omni._submit_with_admission(asyncio.sleep(0))

        wait_task = asyncio.create_task(wait_then_submit())
        sleep_task = asyncio.create_task(omni.sleep(level=1, mode="abort"))
        await asyncio.sleep(0.05)
        assert not wait_task.done()
        assert omni._admitting == 0
        await asyncio.wait_for(sleep_task, timeout=1)
        assert rpc_started.is_set()

        wait_task.cancel()
        with pytest.raises(asyncio.CancelledError):
            await wait_task
        assert omni._admitting == 0

    asyncio.run(run())


@pytest.mark.cpu
def test_streaming_in_flight_add_blocks_sleep():
    """Sleep must wait while a streaming ADD/update holds an admission slot."""

    async def run() -> None:
        omni = _make_omni(stage_types=["llm"])
        add_started = asyncio.Event()
        add_release = asyncio.Event()
        rpc_started = asyncio.Event()

        async def rpc_side_effect(**kwargs):
            if kwargs.get("method") == "sleep":
                rpc_started.set()
            return [True]

        omni.collective_rpc = AsyncMock(side_effect=rpc_side_effect)

        async def slow_add() -> None:
            add_started.set()
            await add_release.wait()

        add_task = asyncio.create_task(omni._submit_with_admission(slow_add()))
        await add_started.wait()
        sleep_task = asyncio.create_task(omni.sleep(level=1, mode="abort"))
        await asyncio.sleep(0.05)
        assert not sleep_task.done()
        assert not rpc_started.is_set()
        assert omni._admitting == 1

        add_release.set()
        await asyncio.wait_for(add_task, timeout=1)
        await asyncio.wait_for(sleep_task, timeout=1)
        assert rpc_started.is_set()
        assert omni._admitting == 0

    asyncio.run(run())


@pytest.mark.cpu
def test_wake_up_restores_admission_for_diffusion_only():
    """Pure diffusion must keep sleep → wake → generate (no resume)."""

    async def run() -> None:
        omni = _make_omni(stage_types=["diffusion"])
        omni._sleep_diffusion = AsyncMock(return_value=[OmniACK(task_id="d", status="SUCCESS", stage_id=0, rank=0)])
        omni._wake_diffusion = AsyncMock(return_value=[OmniACK(task_id="w", status="SUCCESS", stage_id=0, rank=0)])

        await omni.sleep(level=1)
        assert omni._paused is True

        async def wait_for_admission() -> None:
            async with omni._pause_cond:
                await omni._pause_cond.wait_for(lambda: not omni._paused)

        waiter = asyncio.create_task(wait_for_admission())
        await omni.wake_up()
        await asyncio.wait_for(waiter, timeout=1.0)
        assert omni._paused is False
        assert omni._hold_admission_until_resume is False
        assert not omni._sleeping_tags

    asyncio.run(run())


@pytest.mark.cpu
def test_pause_then_sleep_wake_keeps_admission_paused_for_diffusion():
    """Explicit pause_generation still requires resume after diffusion wake."""

    async def run() -> None:
        omni = _make_omni(stage_types=["diffusion"])
        omni.reset_prefix_cache = AsyncMock(return_value=True)
        omni.reset_mm_cache = AsyncMock()
        omni.reset_encoder_cache = AsyncMock()
        omni._sleep_diffusion = AsyncMock(return_value=[OmniACK(task_id="d", status="SUCCESS", stage_id=0, rank=0)])
        omni._wake_diffusion = AsyncMock(return_value=[OmniACK(task_id="w", status="SUCCESS", stage_id=0, rank=0)])

        await omni.pause_generation()
        await omni.sleep(level=1)
        await omni.wake_up()

        assert omni._paused is True
        assert omni._hold_admission_until_resume is True
        await omni.resume_generation()
        assert omni._paused is False

    asyncio.run(run())


@pytest.mark.cpu
def test_partial_wake_does_not_skip_remaining_sleeping_stage():
    """sleep(stage_ids=[0]) then wake([0]) must not skip a later wake([1])."""

    async def run() -> None:
        omni = _make_omni(stage_types=["llm", "llm"])
        await omni.sleep(stage_ids=[0, 1], level=1, mode="abort")
        assert omni._stage_sleeping_tags.keys() == {0, 1}

        await omni.wake_up(stage_ids=[0])
        assert 0 not in omni._stage_sleeping_tags
        assert 1 in omni._stage_sleeping_tags
        assert CuMemTag.WEIGHTS.value in omni._sleeping_tags

        omni.collective_rpc.reset_mock()
        acks = await omni.wake_up(stage_ids=[1])
        assert acks
        omni.collective_rpc.assert_awaited_once()
        wake_kwargs = omni.collective_rpc.await_args.kwargs
        assert wake_kwargs["method"] == "wake_up"
        assert wake_kwargs["stage_ids"] == [1]
        assert not omni._sleeping_tags
        assert not omni._stage_sleeping_tags

    asyncio.run(run())


# ───────────────────── diffusion pause_generation(mode="keep") ─────────────────────


def _rpc_methods(omni: AsyncOmni) -> list[tuple[str, list[int] | None]]:
    return [(call.kwargs["method"], call.kwargs.get("stage_ids")) for call in omni.collective_rpc.await_args_list]


@pytest.mark.cpu
def test_diffusion_keep_routes_to_backend():
    async def run() -> None:
        omni = _make_omni(stage_types=["diffusion"])

        await omni.pause_generation(mode="keep", clear_cache=False)

        omni.collective_rpc.assert_awaited_once_with(
            method="pause_scheduler",
            args=(),
            kwargs={"mode": "keep"},
            stage_ids=[0],
        )
        assert await omni.is_paused() is True
        assert omni._hold_admission_until_resume is True

    asyncio.run(run())


@pytest.mark.cpu
@pytest.mark.parametrize(
    "pause_kwargs",
    [
        {},
        {"mode": "abort"},
        {"mode": "wait"},
        {"mode": "keep", "wait_for_inflight_requests": True},
    ],
)
def test_diffusion_non_keep_modes_pause_frontend_only(pause_kwargs):
    async def run() -> None:
        omni = _make_omni(stage_types=["diffusion"])
        omni.reset_prefix_cache = AsyncMock(return_value=True)
        omni.reset_mm_cache = AsyncMock()
        omni.reset_encoder_cache = AsyncMock()

        await omni.pause_generation(**pause_kwargs)
        assert await omni.is_paused() is True
        omni.collective_rpc.assert_not_awaited()

        await omni.resume_generation()
        omni.collective_rpc.assert_not_awaited()
        assert await omni.is_paused() is False

    asyncio.run(run())


@pytest.mark.cpu
def test_mixed_engine_keep_sends_engine_core_and_diffusion_pauses():
    async def run() -> None:
        omni = _make_omni(stage_types=["llm", "diffusion"])
        omni.reset_prefix_cache = AsyncMock(return_value=True)
        omni.reset_mm_cache = AsyncMock()
        omni.reset_encoder_cache = AsyncMock()

        await omni.pause_generation(mode="keep", clear_cache=True)

        assert omni.collective_rpc.await_args_list[0].kwargs == {
            "method": "pause_scheduler",
            "args": (),
            "kwargs": {"mode": "keep", "clear_cache": True},
            "stage_ids": [0],
        }
        assert omni.collective_rpc.await_args_list[1].kwargs == {
            "method": "pause_scheduler",
            "args": (),
            "kwargs": {"mode": "keep"},
            "stage_ids": [1],
        }
        # Only P0 needs clearing here: pause_scheduler already resets P1.
        omni.reset_prefix_cache.assert_not_awaited()
        omni._clear_frontend_mm_cache.assert_awaited_once_with()

        await omni.resume_generation()
        assert _rpc_methods(omni)[2:] == [("resume_scheduler", [0]), ("resume_scheduler", [1])]

    asyncio.run(run())


@pytest.mark.cpu
def test_keep_targets_only_requested_diffusion_stages():
    async def run() -> None:
        omni = _make_omni(stage_types=["diffusion", "diffusion"])

        await omni.pause_generation(mode="keep", clear_cache=False, stage_ids=[1])
        assert _rpc_methods(omni) == [("pause_scheduler", [1])]

        await omni.resume_generation(stage_ids=[0])
        assert _rpc_methods(omni) == [("pause_scheduler", [1])]
        # Stage 1's scheduler is still closed: admission must stay closed too,
        # otherwise new requests queue on a stage that will not schedule them.
        assert await omni.is_paused() is True

        await omni.resume_generation(stage_ids=[1])
        assert _rpc_methods(omni) == [("pause_scheduler", [1]), ("resume_scheduler", [1])]
        assert await omni.is_paused() is False

        await omni.resume_generation()
        assert len(_rpc_methods(omni)) == 2

    asyncio.run(run())


@pytest.mark.cpu
def test_keep_then_sleep_wake_resume_keeps_admission_paused_until_resume():
    async def run() -> None:
        omni = _make_omni(stage_types=["diffusion"])
        omni.reset_prefix_cache = AsyncMock(return_value=True)
        omni.reset_encoder_cache = AsyncMock()
        omni.collective_rpc = AsyncMock(
            side_effect=lambda **kw: (
                [OmniACK(task_id="t", status="SUCCESS", stage_id=0, rank=0)]
                if kw["method"] in {"handle_sleep_task", "handle_wake_task"}
                else [None]
            )
        )

        await omni.pause_generation(mode="keep", clear_cache=False)
        await omni.sleep(level=1)
        await omni.wake_up()
        assert await omni.is_paused() is True

        await omni.resume_generation()
        assert await omni.is_paused() is False
        assert [m for m, _ in _rpc_methods(omni)] == [
            "pause_scheduler",
            "handle_sleep_task",
            "handle_wake_task",
            "resume_scheduler",
        ]

    asyncio.run(run())


@pytest.mark.cpu
@pytest.mark.parametrize(
    "failure",
    [
        AsyncMock(side_effect=NotImplementedError("request-level execution only")),
        AsyncMock(return_value=[{"supported": False, "error": "TimeoutError: outputs did not drain"}]),
    ],
)
def test_keep_failure_surfaces_and_leaves_explicit_resume_possible(failure):
    async def run() -> None:
        omni = _make_omni(stage_types=["diffusion"])
        omni.collective_rpc = failure

        with pytest.raises((NotImplementedError, RuntimeError)):
            await omni.pause_generation(mode="keep", clear_cache=False)

        assert await omni.is_paused() is True
        assert omni._paused_stage_ids == {0}

        omni.collective_rpc = AsyncMock(return_value=[None])
        await omni.resume_generation()
        omni.collective_rpc.assert_awaited_once_with(
            method="resume_scheduler",
            args=(),
            kwargs=None,
            stage_ids=[0],
        )
        assert await omni.is_paused() is False
        assert omni._paused_stage_ids == set()

    asyncio.run(run())


@pytest.mark.cpu
def test_resume_failure_keeps_admission_paused_and_target_recorded():
    async def run() -> None:
        omni = _make_omni(stage_types=["diffusion"])
        await omni.pause_generation(mode="keep", clear_cache=False)

        omni.collective_rpc = AsyncMock(return_value=[{"error": "replica gone"}])
        with pytest.raises(RuntimeError, match="resume_scheduler failed"):
            await omni.resume_generation()

        assert await omni.is_paused() is True
        assert omni._paused_stage_ids == {0}

    asyncio.run(run())


@pytest.mark.cpu
@pytest.mark.parametrize("first, second", [([1], [0]), ([0], [1])])
def test_mixed_engine_partial_resume_keeps_admission_paused(first, second):
    async def run() -> None:
        omni = _make_omni(stage_types=["llm", "diffusion"])
        await omni.pause_generation(mode="keep", clear_cache=False)

        await omni.resume_generation(stage_ids=first)
        assert await omni.is_paused() is True

        await omni.resume_generation(stage_ids=second)
        assert await omni.is_paused() is False
        assert _rpc_methods(omni)[2:] == [("resume_scheduler", first), ("resume_scheduler", second)]

    asyncio.run(run())


@pytest.mark.cpu
def test_two_ar_stages_partial_resume_keeps_admission_paused():
    async def run() -> None:
        omni = _make_omni(stage_types=["llm", "llm"])
        omni.reset_prefix_cache = AsyncMock(return_value=True)
        omni.reset_mm_cache = AsyncMock()
        omni.reset_encoder_cache = AsyncMock()
        await omni.pause_generation(mode="abort")

        await omni.resume_generation(stage_ids=[0])
        assert await omni.is_paused() is True

        await omni.resume_generation(stage_ids=[1])
        assert await omni.is_paused() is False

    asyncio.run(run())


@pytest.mark.cpu
@pytest.mark.parametrize("method", ["reset_prefix_cache", "reset_encoder_cache", "reset_mm_cache"])
@pytest.mark.parametrize("stage_ids, targets", [(None, [0, 2]), ([2], [2]), ([1], []), ([], [])])
def test_cache_resets_respect_stage_selection(method, stage_ids, targets):
    async def run():
        omni = _make_omni(stage_types=["llm", "diffusion", "llm"])
        await getattr(omni, method)(stage_ids=stage_ids, timeout=2.0)
        if targets:
            assert omni.collective_rpc.await_args.kwargs["stage_ids"] == targets
            assert omni.collective_rpc.await_args.kwargs["timeout"] == 2.0
        else:
            omni.collective_rpc.assert_not_awaited()
        assert omni._clear_frontend_mm_cache.await_count == int(method == "reset_mm_cache" and 0 in targets)

    asyncio.run(run())


@pytest.mark.cpu
@pytest.mark.parametrize("method", ["reset_prefix_cache", "reset_encoder_cache", "reset_mm_cache"])
@pytest.mark.parametrize("failure", [{"todo": "unsupported"}, {"supported": False}, {"error": "reset failed"}])
def test_cache_resets_reject_failure_from_any_replica(method, failure):
    async def run():
        omni = _make_omni(stage_types=["llm"])
        # Exercise the actual collective_rpc too: a single stage can have
        # multiple replicas, so result indexes are not stage IDs.
        del omni.collective_rpc
        omni.engine.collective_rpc_async.return_value = [True, failure]
        with pytest.raises(RuntimeError, match=method):
            await getattr(omni, method)()

    asyncio.run(run())


@pytest.mark.cpu
def test_prefix_reset_returns_false_if_any_replica_refuses():
    async def run():
        omni = _make_omni(stage_types=["llm"])
        omni.collective_rpc.return_value = [True, [True, False]]
        assert await omni.reset_prefix_cache() is False

    asyncio.run(run())


@pytest.mark.cpu
@pytest.mark.parametrize("operation", ["pause_generation", "sleep"])
@pytest.mark.parametrize("stage_ids", [[0], [2]])
def test_pause_and_sleep_do_not_reset_unselected_stages_or_reset_twice(operation, stage_ids):
    async def run():
        omni = _make_omni(stage_types=["llm", "diffusion", "llm"])
        kwargs = {"clear_cache": True} if operation == "pause_generation" else {}
        await getattr(omni, operation)(stage_ids=stage_ids, **kwargs)
        assert omni.collective_rpc.await_count == 1
        rpc = omni.collective_rpc.await_args.kwargs
        assert rpc["method"] == ("pause_scheduler" if operation == "pause_generation" else "sleep")
        assert rpc["stage_ids"] == stage_ids
        assert omni._clear_frontend_mm_cache.await_count == int(0 in stage_ids)

    asyncio.run(run())


_SLEEP_TAGS = {CuMemTag.WEIGHTS.value, CuMemTag.KV_CACHE.value}

# In-process stages return OmniACK, subprocess stages return its dict form,
# and StagePool returns an error dict when the RPC itself failed.
_FAILED_DIFFUSION_RESULTS = [
    pytest.param(OmniACK(task_id="t", status="ERROR", error_msg="out of memory"), id="ack"),
    pytest.param({"task_id": "t", "status": "ERROR", "error_msg": "out of memory"}, id="ack-dict"),
    pytest.param({"supported": False, "error": "out of memory"}, id="rpc-error"),
]


@pytest.mark.cpu
@pytest.mark.parametrize("result", _FAILED_DIFFUSION_RESULTS)
def test_sleep_raises_when_diffusion_stage_fails(result):
    async def run() -> None:
        omni = _make_omni(stage_types=["diffusion"])
        omni.collective_rpc = AsyncMock(return_value=[result])

        with pytest.raises(RuntimeError, match="handle_sleep_task failed: out of memory"):
            await omni.sleep(level=1)

        # The stage may be partly asleep, so it stays on record for wake_up.
        assert omni._sleeping_tags == _SLEEP_TAGS

    asyncio.run(run())


@pytest.mark.cpu
@pytest.mark.parametrize("result", _FAILED_DIFFUSION_RESULTS)
def test_wake_up_raises_when_diffusion_stage_fails(result):
    async def run() -> None:
        omni = _make_omni(stage_types=["diffusion"])
        await omni.sleep(level=1)
        omni.collective_rpc = AsyncMock(return_value=[result])

        with pytest.raises(RuntimeError, match="handle_wake_task failed: out of memory"):
            await omni.wake_up()

        assert omni._sleeping_tags == _SLEEP_TAGS
        assert omni._paused is True

    asyncio.run(run())


@pytest.mark.cpu
def test_sleep_records_all_stages_when_diffusion_stage_fails():
    async def run() -> None:
        omni = _make_omni(stage_types=["llm", "diffusion"])
        omni._sleep_diffusion = AsyncMock(side_effect=RuntimeError("handle_sleep_task failed"))

        with pytest.raises(RuntimeError):
            await omni.sleep(level=1)

        assert omni._stage_sleeping_tags == {0: _SLEEP_TAGS, 1: _SLEEP_TAGS}

    asyncio.run(run())


@pytest.mark.cpu
def test_wake_up_clears_ar_stage_when_diffusion_stage_fails():
    async def run() -> None:
        omni = _make_omni(stage_types=["llm", "diffusion"])
        await omni.sleep(level=1)
        omni._wake_diffusion = AsyncMock(side_effect=RuntimeError("handle_wake_task failed"))

        with pytest.raises(RuntimeError):
            await omni.wake_up()

        assert omni._stage_sleeping_tags == {1: _SLEEP_TAGS}

    asyncio.run(run())


@pytest.mark.cpu
def test_sleep_level2_is_recorded_when_diffusion_stage_fails():
    async def run() -> None:
        omni = _make_omni(stage_types=["llm", "diffusion"])
        omni._sleep_diffusion = AsyncMock(side_effect=RuntimeError("handle_sleep_task failed"))

        with pytest.raises(RuntimeError):
            await omni.sleep(level=2)

        with pytest.raises(NotImplementedError):
            await omni.wake_up(stage_ids=[0])

    asyncio.run(run())


@pytest.mark.cpu
def test_wake_up_reaches_diffusion_stage_after_failed_sleep():
    async def run() -> None:
        omni = _make_omni(stage_types=["diffusion"])
        omni.collective_rpc = AsyncMock(
            return_value=[
                [
                    OmniACK(task_id="t", status="SUCCESS", stage_id=0, rank=0),
                    OmniACK(task_id="t", status="ERROR", error_msg="out of memory"),
                ]
            ]
        )
        with pytest.raises(RuntimeError, match="out of memory"):
            await omni.sleep(level=1)

        omni.collective_rpc = AsyncMock(return_value=[OmniACK(task_id="t", status="SUCCESS", stage_id=0, rank=0)])
        await omni.wake_up()

        omni.collective_rpc.assert_awaited_once()
        assert not omni._sleeping_tags
        assert omni._paused is False

    asyncio.run(run())


@pytest.mark.cpu
def test_wake_up_clears_diffusion_stages_that_woke_before_a_failure():
    async def run() -> None:
        omni = _make_omni(stage_types=["diffusion", "diffusion"])
        await omni.sleep(level=1)
        omni.collective_rpc = AsyncMock(
            side_effect=[
                [OmniACK(task_id="t", status="SUCCESS", stage_id=0, rank=0)],
                [OmniACK(task_id="t", status="ERROR", error_msg="out of memory")],
            ]
        )

        with pytest.raises(RuntimeError, match="out of memory"):
            await omni.wake_up()

        assert omni._stage_sleeping_tags == {1: _SLEEP_TAGS}

    asyncio.run(run())


@pytest.mark.cpu
def test_wake_up_settles_once_for_several_diffusion_stages(mocker):
    async def run() -> None:
        omni = _make_omni(stage_types=["diffusion", "diffusion"])
        await omni.sleep(level=1)
        settle = mocker.patch("vllm_omni.entrypoints.async_omni.asyncio.sleep", new=AsyncMock())

        await omni.wake_up()

        assert omni.collective_rpc.await_count == 3
        settle.assert_awaited_once_with(0.1)

    asyncio.run(run())


@pytest.mark.cpu
@pytest.mark.parametrize("result", [{"supported": False}, {"todo": "not supported yet"}], ids=["unsupported", "todo"])
def test_sleep_raises_on_rpc_result_without_error(result):
    async def run() -> None:
        omni = _make_omni(stage_types=["diffusion"])
        omni.collective_rpc = AsyncMock(return_value=[result])

        with pytest.raises(RuntimeError, match="handle_sleep_task failed"):
            await omni.sleep(level=1)

    asyncio.run(run())


@pytest.mark.cpu
def test_rpc_failure_result_is_not_resolved_as_ack():
    async def run() -> None:
        omni = _make_omni(stage_types=["diffusion"])
        omni.event_resolver.resolve = AsyncMock()
        omni.collective_rpc = AsyncMock(return_value=[{"supported": False, "error": "out of memory"}])

        with pytest.raises(RuntimeError, match="out of memory"):
            await omni.sleep(level=1)

        omni.event_resolver.resolve.assert_not_awaited()

    asyncio.run(run())


@pytest.mark.cpu
def test_sleep_raises_with_reason_of_rpc_error_envelope():
    async def run() -> None:
        omni = _make_omni(stage_types=["diffusion"])
        omni.collective_rpc = AsyncMock(return_value=[{"error": True, "reason": "worker crashed"}])

        with pytest.raises(RuntimeError, match="handle_sleep_task failed: worker crashed"):
            await omni.sleep(level=1)

    asyncio.run(run())


@pytest.mark.cpu
def test_failed_level2_sleep_can_still_be_woken():
    async def run() -> None:
        omni = _make_omni(stage_types=["diffusion"])
        omni.collective_rpc = AsyncMock(return_value=[OmniACK(task_id="t", status="ERROR", error_msg="out of memory")])
        with pytest.raises(RuntimeError, match="out of memory"):
            await omni.sleep(level=2)

        omni.collective_rpc = AsyncMock(return_value=[OmniACK(task_id="t", status="SUCCESS", stage_id=0, rank=0)])
        await omni.wake_up()

        omni.collective_rpc.assert_awaited_once()
        assert omni._paused is False

    asyncio.run(run())


@pytest.mark.cpu
def test_partial_level2_sleep_still_blocks_wake_up():
    async def run() -> None:
        omni = _make_omni(stage_types=["diffusion"])
        omni.collective_rpc = AsyncMock(
            return_value=[
                [
                    OmniACK(task_id="t", status="SUCCESS", stage_id=0, rank=0),
                    OmniACK(task_id="t", status="ERROR", error_msg="out of memory"),
                ]
            ]
        )
        with pytest.raises(RuntimeError, match="out of memory"):
            await omni.sleep(level=2)

        with pytest.raises(NotImplementedError):
            await omni.wake_up()

    asyncio.run(run())


@pytest.mark.cpu
def test_is_sleeping_for_given_stages():
    async def run() -> None:
        omni = _make_omni(stage_types=["llm", "diffusion"])
        await omni.sleep(stage_ids=[1], level=1)

        assert await omni.is_sleeping(stage_ids=[1])
        assert not await omni.is_sleeping(stage_ids=[0])

    asyncio.run(run())