#!/usr/bin/env python3
"""
Скрипт метрик для VPS: CPU, RAM, диск.
Запуск: python3 vps-metrics-api.py [--port 3497]
Установи на каждый VPS и открой порт в файрволе (3497/tcp).

Systemd (опционально):
  sudo cp vps-metrics-api.py /usr/local/bin/
  sudo chmod +x /usr/local/bin/vps-metrics-api.py
  Создай юнит /etc/systemd/system/vps-metrics.service с ExecStart=/usr/bin/python3 /usr/local/bin/vps-metrics-api.py
  sudo systemctl enable --now vps-metrics
"""
import json
import subprocess
import sys
from http.server import HTTPServer, BaseHTTPRequestHandler

PORT = 3497


def get_metrics():
    """Собирает метрики из /proc и df. Только stdlib."""
    out = {}
    try:
        # Load average (1 min)
        with open("/proc/loadavg") as f:
            parts = f.read().strip().split()
            out["load_1"] = round(float(parts[0]), 2)
        # Memory: MemTotal, MemAvailable
        mem = {}
        with open("/proc/meminfo") as f:
            for line in f:
                if ":" in line:
                    k, v = line.strip().split(":", 1)
                    mem[k.strip()] = int(v.strip().split()[0])  # kB
        total_kb = mem.get("MemTotal", 0)
        avail_kb = mem.get("MemAvailable", mem.get("MemFree", 0))
        used_kb = total_kb - avail_kb
        out["memory_total_gb"] = round(total_kb / 1024 / 1024, 2)
        out["memory_used_gb"] = round(used_kb / 1024 / 1024, 2)
        out["memory_percent"] = round(100 * used_kb / total_kb, 1) if total_kb else 0
        out["memory.status"] = f"{out['memory_used_gb']:.1f} / {out['memory_total_gb']:.1f} GB"
        # Disk: root /
        result = subprocess.run(
            ["df", "-k", "/"],
            capture_output=True,
            text=True,
            timeout=5,
        )
        if result.returncode == 0 and result.stdout:
            lines = result.stdout.strip().split("\n")
            if len(lines) >= 2:
                parts = lines[1].split()
                if len(parts) >= 4:
                    total_kb = int(parts[1])
                    used_kb = int(parts[2])
                    avail_kb = int(parts[3])
                    total_gb = total_kb / 1024 / 1024
                    used_gb = used_kb / 1024 / 1024
                    avail_gb = avail_kb / 1024 / 1024
                    out["disk_total_gb"] = round(total_gb, 1)
                    out["disk_used_gb"] = round(used_gb, 1)
                    out["disk_free_gb"] = round(avail_gb, 1)
                    out["disk_percent"] = round(100 * used_kb / total_kb, 1) if total_kb else 0
                    out["disk.status"] = f"{out['disk_free_gb']:.1f} / {out['disk_total_gb']:.1f} GB свободно"
        # Uptime
        with open("/proc/uptime") as f:
            out["uptime_seconds"] = int(float(f.read().split()[0]))
    except Exception as e:
        out["error"] = str(e)
    return out


class Handler(BaseHTTPRequestHandler):
    def do_GET(self):
        self.send_response(200)
        self.send_header("Content-Type", "application/json")
        self.end_headers()
        self.wfile.write(json.dumps(get_metrics(), ensure_ascii=False).encode())

    def log_message(self, *args):
        pass


def main():
    port = PORT
    if len(sys.argv) > 1 and sys.argv[1] == "--port" and len(sys.argv) > 2:
        port = int(sys.argv[2])
    print(f"VPS metrics API: http://0.0.0.0:{port}", file=sys.stderr)
    HTTPServer(("0.0.0.0", port), Handler).serve_forever()


if __name__ == "__main__":
    main()