"""事件调度订阅快照的并发回归测试。"""

import pytest

from app.runtime.events import Event, eventmanager
from app.schemas.types import ChainEventType, EventType


class _ImmediateExecutor:
    """在当前线程执行广播 handler，使订阅变更精确发生在调度迭代期间。"""

    @staticmethod
    def submit(func, *args, **kwargs):
        return func(*args, **kwargs)


@pytest.fixture
def isolated_eventmanager(monkeypatch):
    """隔离全局事件总线的订阅表和广播执行器。"""
    monkeypatch.setattr(
        eventmanager,
        "_EventManager__broadcast_subscribers",
        {},
    )
    monkeypatch.setattr(
        eventmanager,
        "_EventManager__chain_subscribers",
        {},
    )
    monkeypatch.setattr(
        eventmanager,
        "_EventManager__handler_instance_resolvers",
        {},
    )
    monkeypatch.setattr(
        eventmanager,
        "_EventManager__executor",
        _ImmediateExecutor(),
    )
    return eventmanager


def test_broadcast_dispatch_uses_subscription_snapshot(isolated_eventmanager):
    """广播事件中新增或移除的 handler 从下一个事件开始生效。"""
    calls = []

    def late_handler(_event):
        calls.append("late")

    def removed_handler(_event):
        calls.append("removed")

    def mutating_handler(_event):
        calls.append("mutating")
        isolated_eventmanager.remove_event_listener(
            EventType.ConfigChanged,
            removed_handler,
        )
        isolated_eventmanager.add_event_listener(
            EventType.ConfigChanged,
            late_handler,
        )

    isolated_eventmanager.add_event_listener(
        EventType.ConfigChanged,
        mutating_handler,
    )
    isolated_eventmanager.add_event_listener(
        EventType.ConfigChanged,
        removed_handler,
    )

    dispatch = isolated_eventmanager._EventManager__dispatch_broadcast_event
    dispatch(Event(EventType.ConfigChanged, {}))
    assert calls == ["mutating", "removed"]

    calls.clear()
    dispatch(Event(EventType.ConfigChanged, {}))
    assert calls == ["mutating", "late"]


def test_sync_chain_dispatch_uses_subscription_snapshot(isolated_eventmanager):
    """同步链式事件中的订阅变更不影响当前处理器序列。"""
    calls = []

    def late_handler(_event):
        calls.append("late")

    def removed_handler(_event):
        calls.append("removed")

    def mutating_handler(_event):
        calls.append("mutating")
        isolated_eventmanager.remove_event_listener(
            ChainEventType.NameRecognize,
            removed_handler,
        )
        isolated_eventmanager.add_event_listener(
            ChainEventType.NameRecognize,
            late_handler,
        )

    isolated_eventmanager.add_event_listener(
        ChainEventType.NameRecognize,
        mutating_handler,
    )
    isolated_eventmanager.add_event_listener(
        ChainEventType.NameRecognize,
        removed_handler,
    )

    dispatch = isolated_eventmanager._EventManager__dispatch_chain_event
    assert dispatch(Event(ChainEventType.NameRecognize, {})) is True
    assert calls == ["mutating", "removed"]

    calls.clear()
    assert dispatch(Event(ChainEventType.NameRecognize, {})) is True
    assert calls == ["mutating", "late"]


@pytest.mark.asyncio
async def test_async_chain_dispatch_uses_subscription_snapshot(
        isolated_eventmanager,
):
    """异步链式事件中的订阅变更不影响当前处理器序列。"""
    calls = []

    async def late_handler(_event):
        calls.append("late")

    async def removed_handler(_event):
        calls.append("removed")

    async def mutating_handler(_event):
        calls.append("mutating")
        isolated_eventmanager.remove_event_listener(
            ChainEventType.NameRecognize,
            removed_handler,
        )
        isolated_eventmanager.add_event_listener(
            ChainEventType.NameRecognize,
            late_handler,
        )

    isolated_eventmanager.add_event_listener(
        ChainEventType.NameRecognize,
        mutating_handler,
    )
    isolated_eventmanager.add_event_listener(
        ChainEventType.NameRecognize,
        removed_handler,
    )

    dispatch = isolated_eventmanager._EventManager__dispatch_chain_event_async
    assert await dispatch(Event(ChainEventType.NameRecognize, {})) is True
    assert calls == ["mutating", "removed"]

    calls.clear()
    assert await dispatch(Event(ChainEventType.NameRecognize, {})) is True
    assert calls == ["mutating", "late"]