import time
from typing import Dict

# category -> unix timestamp until muted
_MUTES: Dict[str, float] = {}


def _cleanup() -> None:
    now = time.time()
    expired = [k for k, until in _MUTES.items() if until <= now]
    for k in expired:
        _MUTES.pop(k, None)


def set_mute(category: str, seconds: int) -> float:
    _cleanup()
    until = time.time() + max(0, seconds)
    _MUTES[category] = until
    return until


def clear_mute(category: str) -> None:
    _MUTES.pop(category, None)


def is_muted(category: str | None) -> bool:
    if not category:
        return False
    _cleanup()
    until = _MUTES.get(category)
    if until is None:
        return False
    if until <= time.time():
        _MUTES.pop(category, None)
        return False
    return True


def list_mutes() -> dict[str, int]:
    _cleanup()
    now = time.time()
    return {k: int(until - now) for k, until in _MUTES.items()}