#!/usr/bin/env python3
"""Prometheus-file_sd-Ziele für die GPU-VMs erzeugen (läuft auf ops).

Die GPU-VMs bekommen ihre Adressen per DHCP (D5), deshalb stehen sie nicht fest in prometheus.yml.
Eingabe ist `tofu output -json gpu_vms` (stdin), dazu die Registry für die Slot-Labels des Healers.

    tofu output -json gpu_vms | python3 monitoring-targets.py --registry sites/knaster/registry.yaml --out DIR

Schreibt DIR/node.json (node_exporter, Port 9100) und DIR/gpu.json (nvidia_gpu_exporter, Port 9835).

Labels je Ziel: instance (VM-Name, bleibt bei IP-Wechsel gleich), vm, pve_node, vmid, slot, slots.
`slot` ist der erste Slot der Registry mit dieser vmid (Reihenfolge der Registry), `slots` alle,
kommagetrennt. VMs ohne Slot bekommen slot="none" (der Healer markiert dann keinen echten Slot).
"""

from __future__ import annotations

import argparse
import json
import sys
from pathlib import Path

import yaml

PORTS = {"node": 9100, "gpu": 9835}


def slots_by_vmid(registry: dict) -> dict[str, list[str]]:
    out: dict[str, list[str]] = {}
    for name, slot in (registry.get("slots") or {}).items():
        vmid = str((slot.get("ops") or {}).get("vmid", ""))
        if vmid:
            out.setdefault(vmid, []).append(name)
    return out


def build_targets(gpu_vms: dict, registry: dict) -> dict[str, list[dict]]:
    by_vmid = slots_by_vmid(registry)
    result: dict[str, list[dict]] = {job: [] for job in PORTS}
    for name in sorted(gpu_vms):
        vm = gpu_vms[name]
        if not vm.get("ipv4"):
            print(f"Warnung: {name} hat keine IPv4 (Gast-Agent?), übersprungen", file=sys.stderr)
            continue
        vmid = str(vm["vmid"])
        slots = by_vmid.get(vmid, [])
        labels = {
            "instance": name,
            "vm": name,
            "pve_node": vm["node"],
            "vmid": vmid,
            "slot": slots[0] if slots else "none",
            "slots": ",".join(slots),
        }
        for job, port in PORTS.items():
            result[job].append({"targets": [f"{vm['ipv4']}:{port}"], "labels": labels})
    return result


def main() -> int:
    ap = argparse.ArgumentParser(description=__doc__.splitlines()[0])
    ap.add_argument("--registry", required=True, type=Path)
    ap.add_argument("--out", required=True, type=Path)
    args = ap.parse_args()

    gpu_vms = json.load(sys.stdin)
    registry = yaml.safe_load(args.registry.read_text(encoding="utf-8"))
    targets = build_targets(gpu_vms, registry)
    args.out.mkdir(parents=True, exist_ok=True)
    for job, entries in targets.items():
        path = args.out / f"{job}.json"
        tmp = path.with_suffix(".tmp")
        tmp.write_text(json.dumps(entries, indent=2, sort_keys=True) + "\n", encoding="utf-8")
        tmp.replace(path)
        print(f"{path}: {len(entries)} Ziele")
    return 0 if targets["node"] else 1


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