"""后台 watch 无新任务时的限流 warning（FishMeasure / FishAction 共用）。"""

from __future__ import annotations

import os
import time
from pathlib import Path

from loguru import logger


def idle_warn_interval_sec(override_env: str) -> float:
    """优先读 override_env，否则 FISH_WATCH_IDLE_WARN_INTERVAL_SEC，默认 120。"""
    v = os.environ.get(override_env)
    if v is not None and str(v).strip() != "":
        return float(v)
    return float(os.environ.get("FISH_WATCH_IDLE_WARN_INTERVAL_SEC", "120"))


class IdleWatchWarnState:
    """记录上次告警时间；有推理成功时重置计时。"""

    __slots__ = ("_last_mono",)

    def __init__(self) -> None:
        self._last_mono = time.monotonic()

    def on_did_work(self) -> None:
        self._last_mono = time.monotonic()


def maybe_warn_idle_watch(
    *,
    did_work: bool,
    log_tag: str,
    algo_name: str,
    idle_hint: str,
    watch_dir: Path,
    state: IdleWatchWarnState,
    interval_sec: float,
) -> None:
    """本轮未跑推理时按 interval 限流打 warning；interval<=0 则每轮无任务都打。"""
    if did_work:
        state.on_did_work()
        return
    now = time.monotonic()
    if interval_sec > 0 and now - state._last_mono < interval_sec:
        return
    state._last_mono = now
    logger.warning(
        "[{}] 本轮无新数据可供 {} 处理（{}） | dir={}",
        log_tag,
        algo_name,
        idle_hint,
        watch_dir,
    )