#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""Probe temperatura/load CPU DS920 — HTTP GET /thermal su :9191.

Avvio (sul DS920, utente daniely):
  nohup python3 ds920_thermal_probe.py >> /tmp/thermal-probe.log 2>&1 &

O via Task Scheduler Synology all'avvio.
"""

from __future__ import annotations

import json
import os
from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer


PORT = int(os.environ.get("THERMAL_PROBE_PORT", "9191"))
HWMON = os.environ.get("THERMAL_HWMON", "/sys/class/hwmon/hwmon0")


def read_metrics() -> dict:
    temps = []
    try:
        for name in sorted(os.listdir(HWMON)):
            if name.startswith("temp") and name.endswith("_input"):
                with open(os.path.join(HWMON, name), encoding="utf-8") as f:
                    temps.append(int(f.read().strip()) / 1000.0)
    except OSError:
        pass
    load1, load5, load15 = os.getloadavg()
    nproc = os.cpu_count() or 4
    return {
        "ok": True,
        "host": os.uname().nodename,
        "cpu_temp_c": max(temps) if temps else None,
        "temps_c": temps,
        "load1": load1,
        "load5": load5,
        "load15": load15,
        "nproc": nproc,
        "cpu_target_load": round(nproc * 0.75, 2),
    }


class Handler(BaseHTTPRequestHandler):
    def log_message(self, fmt: str, *args) -> None:  # noqa: A003
        return

    def do_GET(self) -> None:  # noqa: N802
        if self.path.split("?")[0] not in ("/", "/thermal", "/health"):
            self.send_response(404)
            self.end_headers()
            return
        body = json.dumps(read_metrics()).encode()
        self.send_response(200)
        self.send_header("Content-Type", "application/json")
        self.send_header("Content-Length", str(len(body)))
        self.end_headers()
        self.wfile.write(body)


def main() -> None:
    server = ThreadingHTTPServer(("0.0.0.0", PORT), Handler)
    print(f"thermal probe listening on 0.0.0.0:{PORT}", flush=True)
    server.serve_forever()


if __name__ == "__main__":
    main()