'''
EMS broadcast ownership regressions.

'''
from contextlib import asynccontextmanager as acm

import trio

from piker.clearing import _ems


def test_dark_clearing_owns_non_strict_subscription(
    monkeypatch,
) -> None:
    '''
    Dark clearing must not mutate another feed consumer's lag policy.

    `clear_dark_triggers()` previously assigned `_raise_on_lag` on
    whichever root or temporary receiver was stored in `Flume.stream`.
    That changed private shared state and made behavior depend on feed
    cache ownership. Supply a stream whose subscription records the
    public lag-policy argument and yields a distinct child. Replace
    the hot trigger loop with a checkpointing probe, then prove the
    non-strict child is entered, passed to the core, and closed only
    after processing completes while the source remains untouched.

    '''
    events: list[tuple] = []
    child = object()

    class QuoteStream:
        '''
        Record public subscription ownership without quote traffic.

        '''
        @acm
        async def subscribe(self, raise_on_lag: bool = True):
            '''
            Yield one dedicated child for the wrapper lifetime.

            '''
            events.append(('enter', raise_on_lag))
            try:
                yield child
            finally:
                events.append(('exit', raise_on_lag))

    async def clear_core(*args) -> None:
        '''
        Prove the child remains owned while processing runs.

        '''
        events.append(('core', args[2] is child))
        await trio.lowlevel.checkpoint()

    monkeypatch.setattr(
        _ems,
        '_clear_dark_triggers',
        clear_core,
    )

    async def main() -> None:
        stream = QuoteStream()
        await _ems.clear_dark_triggers(
            object(),
            object(),
            stream,
            'ib',
            'nvda.nasdaq.ib',
            object(),
        )
        assert not hasattr(stream, '_raise_on_lag')

    trio.run(main)
    assert events == [
        ('enter', False),
        ('core', True),
        ('exit', False),
    ]