# -*- coding: utf-8 -*-
"""轻量后台任务：企业微信 23:00（北京时间）日报。"""
from __future__ import annotations

import logging
import os
import threading
from datetime import datetime, timedelta, timezone
from pathlib import Path

from app.config import Config, DATA_DIR
from app import db as database
from app import wecom

log = logging.getLogger("gold_monitor.scheduler")
BJT = timezone(timedelta(hours=8))

_started = False
_lock = threading.Lock()


def _try_claim_daily(day: str) -> bool:
    """多 worker 下用独占锁文件抢占当日日报；成功后再写 settings 备查。"""
    DATA_DIR.mkdir(parents=True, exist_ok=True)
    lock_path = Path(DATA_DIR) / f"wecom_daily_{day}.sent"
    try:
        fd = os.open(str(lock_path), os.O_CREAT | os.O_EXCL | os.O_WRONLY)
        try:
            os.write(fd, f"pid={os.getpid()} ts={time_stamp()}\n".encode("utf-8"))
        finally:
            os.close(fd)
    except FileExistsError:
        return False
    try:
        with database.get_db() as conn:
            database.set_setting(conn, wecom.SETTING_DAILY_LAST, day)
    except Exception:  # noqa: BLE001
        log.exception("record daily last failed")
    return True


def time_stamp() -> str:
    return datetime.now(BJT).isoformat()


def _daily_tick() -> None:
    hour = int(Config.WECOM_DAILY_HOUR)
    minute = int(Config.WECOM_DAILY_MINUTE)
    now = datetime.now(BJT)
    if now.hour != hour or now.minute != minute:
        return
    if not wecom.is_enabled() or not wecom.webhook_url():
        return
    day = now.strftime("%Y-%m-%d")
    if not _try_claim_daily(day):
        return
    lock_path = Path(DATA_DIR) / f"wecom_daily_{day}.sent"
    try:
        ok, detail = wecom.send_daily_reports(day)
        log.info("wecom daily %s ok=%s detail=%s", day, ok, detail)
        if not ok:
            try:
                lock_path.unlink(missing_ok=True)
            except OSError:
                pass
    except Exception:  # noqa: BLE001
        log.exception("wecom daily failed")
        try:
            lock_path.unlink(missing_ok=True)
        except OSError:
            pass


def _loop(stop_event: threading.Event) -> None:
    # 错开启动，减少多 worker 同时抢
    jitter = (Path(DATA_DIR).stat().st_mtime_ns % 17) if DATA_DIR.exists() else 0
    stop_event.wait(3 + int(jitter) % 5)
    while not stop_event.is_set():
        try:
            _daily_tick()
        except Exception:  # noqa: BLE001
            log.exception("scheduler tick error")
        stop_event.wait(20)


def start_background_jobs() -> None:
    """幂等启动；gunicorn 多 worker 各自起线程，靠 settings 去重。"""
    global _started
    with _lock:
        if _started:
            return
        _started = True
        stop = threading.Event()
        t = threading.Thread(target=_loop, args=(stop,), name="wecom-daily", daemon=True)
        t.start()
        log.info(
            "wecom daily scheduler started (BJT %02d:%02d)",
            int(Config.WECOM_DAILY_HOUR),
            int(Config.WECOM_DAILY_MINUTE),
        )