from PyQt6.QtCore import QObject, QTimer, QElapsedTimer
import logging
import time

from config import Config

class EventLoopJitterMonitor(QObject):
    def __init__(
        self,
        parent=None,
        interval_ms: int = 20,
        jitter_threshold_ms: int = 100,
        log_cooldown_s: float = 1.0,
    ):
        super().__init__(parent)
        self._interval = interval_ms
        self._jitter_threshold = jitter_threshold_ms
        self._log_cooldown_s = log_cooldown_s

        self._timer = QTimer(self)
        self._timer.setInterval(self._interval)
        self._timer.timeout.connect(self._on_timeout)

        self._elapsed = QElapsedTimer()
        self._elapsed.start()
        self._last = self._elapsed.elapsed()

        # child logger: e.g. "musicmuster.jitter"
        self._log = logging.getLogger(f"{Config.LOG_NAME}.jitter")
        self._last_log_time = 0.0

    def start(self) -> None:
        self._timer.start()

    def _on_timeout(self) -> None:
        now_ms = self._elapsed.elapsed()
        delta = now_ms - self._last
        self._last = now_ms

        if delta > (self._interval + self._jitter_threshold):
            self._log_jitter(now_ms, delta)

    def _log_jitter(self, now_ms: int, gap_ms: int) -> None:
        now = time.monotonic()

        # simple rate limit: only one log every log_cooldown_s
        if now - self._last_log_time < self._log_cooldown_s:
            return
        self._last_log_time = now

        self._log.warning(
            "Event loop gap detected: t=%d ms, gap=%d ms (interval=%d ms)",
            now_ms,
            gap_ms,
            self._interval,
        )