#!/usr/bin/env python3
"""
watchdog.py - Vahtikoira BatteryMon_3.py:lle
"""

import sys
import time
import subprocess
import logging
from datetime import datetime
from pathlib import Path
from typing import Optional
from logging.handlers import RotatingFileHandler

# ── Asetukset ────────────────────────────────────────────────────────────────
STATUS_FILE    = "/var/www/html/Data/Status.csv"
CONTROL_FILE   = "/var/www/html/Data/Control.csv"
TARGET_SCRIPT  = "BatteryMon_3.py"
MAX_AGE_MIN    = 4
CHECK_INTERVAL = 300
INITIAL_WAIT   = 300 #should be 300
MAX_RESTARTS   = 3
LOG_FILE       = "watchdog.log"
# ─────────────────────────────────────────────────────────────────────────────

logging.basicConfig(
    format="%(asctime)s  %(message)s",
    datefmt="%Y-%m-%d %H:%M:%S",
    handlers=[
        logging.StreamHandler(sys.stdout),
        RotatingFileHandler(LOG_FILE, maxBytes=1_000_000, backupCount=2, encoding="utf-8"),
    ],
)
log = logging.getLogger()
log.setLevel(logging.INFO)

restart_count = 0


def file_age_minutes() -> Optional[float]:
    p = Path(STATUS_FILE)
    if not p.exists():
        return None
    return (datetime.now() - datetime.fromtimestamp(p.stat().st_mtime)).total_seconds() / 60


def is_stopped() -> bool:
    p = Path(CONTROL_FILE)
    if not p.exists():
        return False
    return p.read_text().strip() == "Stop"


def restart():
    global restart_count

    if restart_count >= MAX_RESTARTS:
        log.info("Uudelleenkäynnistysraja täynnä – tarkista käsin!")
        sys.exit(1)

    restart_count += 1
    subprocess.call(["pkill", "-f", TARGET_SCRIPT])
    time.sleep(2)
    subprocess.Popen(
        [sys.executable, TARGET_SCRIPT],
        stdout=subprocess.DEVNULL,
        stderr=subprocess.DEVNULL,
    )
    log.info(f"Käynnistetty ({restart_count}/{MAX_RESTARTS})")


def main():
    global restart_count
    log.info("Vahtikoira käynnistetty")
    time.sleep(INITIAL_WAIT)

    while True:
        age = file_age_minutes()

        if age is not None and age <= MAX_AGE_MIN:
            restart_count = 0
        elif is_stopped():
            log.info("Stop")
        else:
            log.info(f"Käynnistetään – {STATUS_FILE} ikä {age:.0f} min" if age else f"Käynnistetään – {STATUS_FILE} puuttuu")
            restart()

        time.sleep(CHECK_INTERVAL)


if __name__ == "__main__":
    main()