#!/usr/bin/env bash
set -euo pipefail

# Quick fix tool: replace 172.22/16 targets in nodes.json with overlay IPs resolved from hostname.
# Usage: run on server package host: scripts/fix-prom-targets-overlay.sh

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
NODES_JSON="$ROOT/private/argus/metric/prometheus/nodes.json"

require_cmd() { command -v "$1" >/dev/null 2>&1 || { echo "[ERROR] missing command: $1" >&2; exit 1; }; }

backup() {
  local src="$1"; local ts; ts=$(date -u +%Y%m%d-%H%M%SZ)
  cp "$src" "${src%.json}_bak_${ts}.json"
}

prefer_overlay_ip() {
  local host="$1"
  # prefer 10.0/8 then 172.31/16
  getent hosts "$host" | awk '{print $1}' | while read -r ip; do
    if [[ "$ip" =~ ^10\. ]]; then echo "$ip"; return; fi
  done
  getent hosts "$host" | awk '{print $1}' | while read -r ip; do
    if [[ "$ip" =~ ^172\.31\. ]]; then echo "$ip"; return; fi
  done
  # fallback: first A record
  getent hosts "$host" | awk '{print $1; exit}'
}

require_cmd awk
require_cmd sed

if [[ ! -f "$NODES_JSON" ]]; then
  echo "[WARN] nodes.json not found: $NODES_JSON" >&2
  exit 0
fi

backup "$NODES_JSON"

tmp=$(mktemp)
trap 'rm -f "$tmp"' EXIT

changed=0
python3 - "$NODES_JSON" <<'PY' > "$tmp" || {
import ipaddress, json, sys, socket
path=sys.argv[1]
data=json.load(open(path)) if path else []
def resolve(host):
    try:
        infos=socket.getaddrinfo(host,None,family=socket.AF_INET)
        ips=[i[4][0] for i in infos]
        # prefer 10. over 172.31.
        for ip in ips:
            if ip.startswith('10.'): return ip
        for ip in ips:
            if ip.startswith('172.31.'): return ip
        return ips[0] if ips else None
    except OSError:
        return None
gw=ipaddress.ip_network('172.22.0.0/16')
out=[]
changed=False
for item in data:
    ip=item.get('ip')
    host=item.get('hostname') or ''
    try:
        bad = ip and ipaddress.ip_address(ip) in gw
    except Exception:
        bad = False
    if bad and host:
        new=resolve(host)
        if new:
            item=dict(item)
            item['ip']=new
            changed=True
    out.append(item)
json.dump(out, sys.stdout, ensure_ascii=False)
sys.stderr.write('CHANGED' if changed else 'UNCHANGED')
PY

status=$?
marker=$(tail -n1 /dev/stderr 2>/dev/null || true)
if [[ "$status" -ne 0 ]]; then
  echo "[ERROR] failed to rewrite nodes.json" >&2
  exit 1
fi

if grep -q '"ip"\s*:\s*"172\.22\.' "$tmp"; then
  echo "[WARN] some gwbridge targets remain; manual fix may be required" >&2
fi

mv "$tmp" "$NODES_JSON"
echo "[OK] nodes.json updated"

# try to reload Prometheus
if docker ps --format '{{.Names}}' | grep -q '^argus-prometheus$'; then
  docker exec argus-prometheus sh -lc 'pidof prometheus >/dev/null 2>&1 && kill -HUP $(pidof prometheus) || supervisorctl restart prometheus' >/dev/null 2>&1 || true
  echo "[INFO] Prometheus reloaded"
fi

exit 0