#!/usr/bin/env python3
"""homepage-status.py — the homepage status checker.

Reads a service config (a JSON array of service entries), probes each backend,
and writes a status.json atomically. A wip service is not probed; its state
is "wip-open" or "wip-closed" following the wip value in the config.

Usage: homepage-status.py <services.json> <out.json>
"""
import json
import os
import socket
import sys
import tempfile
import urllib.error
import urllib.request
from datetime import datetime, timezone

TIMEOUT = 5  # seconds, per probe (Q11 / Q40)


def probe(host, port, method="tcp"):
    """Return 'up' if the backend answers, else 'down'."""
    if method == "http":
        try:
            urllib.request.urlopen(
                urllib.request.Request("http://%s:%d/" % (host, port)),
                timeout=TIMEOUT,
            )
            return "up"
        except urllib.error.HTTPError:
            return "up"  # an HTTP response of any status means the backend is up
        except Exception:
            return "down"
    try:
        with socket.create_connection((host, port), timeout=TIMEOUT):
            return "up"
    except Exception:
        return "down"


def main(argv):
    if len(argv) != 3:
        sys.stderr.write("usage: homepage-status.py <services.json> <out.json>\n")
        return 2
    services_path, out_path = argv[1], argv[2]
    with open(services_path) as f:
        services = json.load(f)

    results = []
    for svc in services:
        wip = svc.get("wip")
        if wip:
            state = "wip-%s" % wip
        else:
            host, _, port = svc["probe"].rpartition(":")
            state = probe(host, int(port), svc.get("method", "tcp"))
        results.append({
            "name": svc.get("name"),
            "category": svc.get("category", "user"),
            "state": state,
        })

    doc = {
        "generated_at": datetime.now(timezone.utc).strftime("%Y-%m-%dT%H:%M:%SZ"),
        "services": results,
    }

    # Atomic write: a temp file in the same directory, then rename over the target.
    out_dir = os.path.dirname(os.path.abspath(out_path))
    fd, tmp = tempfile.mkstemp(dir=out_dir, prefix=".status.", suffix=".tmp")
    try:
        with os.fdopen(fd, "w") as f:
            json.dump(doc, f)
        os.replace(tmp, out_path)
        os.chmod(out_path, 0o644)  # world-readable so Caddy can serve it
    except Exception:
        if os.path.exists(tmp):
            os.unlink(tmp)
        raise
    return 0


if __name__ == "__main__":
    sys.exit(main(sys.argv))