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

import asyncio
from concurrent.futures import ThreadPoolExecutor
from functools import partial
from time import sleep
from typing import Any

import pytest

from vllm.config import VllmConfig
from vllm.executor.multiproc_worker_utils import (ProcessWorkerWrapper,
                                                  ResultHandler, WorkerMonitor)
from vllm.worker.worker_base import WorkerWrapperBase


class DummyWorkerWrapper(WorkerWrapperBase):
    """Dummy version of vllm.worker.worker.Worker"""

    def worker_method(self, worker_input: Any) -> tuple[int, Any]:
        sleep(0.05)

        if isinstance(worker_input, Exception):
            # simulate error case
            raise worker_input

        return self.rpc_rank, input


def _start_workers() -> tuple[list[ProcessWorkerWrapper], WorkerMonitor]:
    result_handler = ResultHandler()
    vllm_config = VllmConfig()
    workers = [
        ProcessWorkerWrapper(result_handler, DummyWorkerWrapper, vllm_config,
                             rank) for rank in range(8)
    ]

    worker_monitor = WorkerMonitor(workers, result_handler)
    assert not worker_monitor.is_alive()

    result_handler.start()
    worker_monitor.start()
    assert worker_monitor.is_alive()

    return workers, worker_monitor


def test_local_workers() -> None:
    """Test workers with sync task submission"""

    workers, worker_monitor = _start_workers()

    def execute_workers(worker_input: str) -> None:
        worker_outputs = [
            worker.execute_method("worker_method", worker_input)
            for worker in workers
        ]

        for rank, output in enumerate(worker_outputs):
            assert output.get() == (rank, input)

    executor = ThreadPoolExecutor(max_workers=4)

    # Test concurrent submission from different threads
    futures = [
        executor.submit(partial(execute_workers, f"thread {thread_num}"))
        for thread_num in range(4)
    ]

    for future in futures:
        future.result()

    # Test error case
    exception = ValueError("fake error")
    result = workers[0].execute_method("worker_method", exception)
    try:
        result.get()
        pytest.fail("task should have failed")
    except Exception as e:
        assert isinstance(e, ValueError)
        assert str(e) == "fake error"

    # Test cleanup when a worker fails
    assert worker_monitor.is_alive()
    workers[3].process.kill()

    # Other workers should get shut down here
    worker_monitor.join(20)

    # Ensure everything is stopped
    assert not worker_monitor.is_alive()
    assert all(not worker.process.is_alive() for worker in workers)

    # Further attempts to submit tasks should fail
    try:
        _result = workers[0].execute_method("worker_method", "test")
        pytest.fail("task should fail once workers have been shut down")
    except Exception as e:
        assert isinstance(e, ChildProcessError)


# @TODO
# def test_local_workers_clean_shutdown() -> None:
#     """Test clean shutdown"""

#     workers, worker_monitor = _start_workers()

#     assert worker_monitor.is_alive()
#     assert all(worker.process.is_alive() for worker in workers)

#     # Clean shutdown
#     worker_monitor.close()

#     worker_monitor.join(20)

#     # Ensure everything is stopped
#     assert not worker_monitor.is_alive()
#     assert all(not worker.process.is_alive() for worker in workers)

#     # Further attempts to submit tasks should fail
#     try:
#         _result = workers[0].execute_method("worker_method", "test")
#         pytest.fail("task should fail once workers have been shut down")
#     except Exception as e:
#         assert isinstance(e, ChildProcessError)


@pytest.mark.asyncio
async def test_local_workers_async() -> None:
    """Test local workers with async task submission"""

    workers, worker_monitor = _start_workers()

    async def execute_workers(worker_input: str) -> None:
        worker_coros = [
            worker.execute_method_async("worker_method", worker_input)
            for worker in workers
        ]

        results = await asyncio.gather(*worker_coros)
        for rank, result in enumerate(results):
            assert result == (rank, input)

    tasks = [
        asyncio.create_task(execute_workers(f"task {task_num}"))
        for task_num in range(4)
    ]

    for task in tasks:
        await task

    # Test error case
    exception = ValueError("fake error")
    try:
        _result = await workers[0].execute_method_async(
            "worker_method", exception)
        pytest.fail("task should have failed")
    except Exception as e:
        assert isinstance(e, ValueError)
        assert str(e) == "fake error"

    # Test cleanup when a worker fails
    assert worker_monitor.is_alive()
    workers[3].process.kill()

    # Other workers should get shut down here
    worker_monitor.join(20)

    # Ensure everything is stopped
    assert not worker_monitor.is_alive()
    assert all(not worker.process.is_alive() for worker in workers)

    # Further attempts to submit tasks should fail
    try:
        _result = await workers[0].execute_method_async(
            "worker_method", "test")
        pytest.fail("task should fail once workers have been shut down")
    except Exception as e:
        assert isinstance(e, ChildProcessError)
