#!/data/data/com.termux/files/usr/bin/bash
# resolve: hostname -> IP con fallback mDNS (LAN) -> Tailscale DNS -> cache
# Uso:  resolve <hostname>[.local|.tailnet]
# Ej:   resolve lenovo                  # -> 100.69.236.16
#       ping $(resolve hp62a)
#       curl "http://$(resolve dell):8080"
set -e
HOST="${1:-}"
[[ -z "$HOST" ]] && { echo "Uso: resolve <hostname>" >&2; exit 1; }

CACHE="$HOME/.ssh/resolve-cache"
TAILSCALE_DOMAIN="${TAILSCALE_DOMAIN:-tailb0bb74.ts.net}"
MDNS_TIMEOUT="${MDNS_TIMEOUT:-1}"

QUERY="${HOST%.local}"
QUERY="${QUERY%.${TAILSCALE_DOMAIN}}"

declare -A ALIASES=(
    [dell]="dell-latitude3400"
    [lenovo]="lenovo-ideapad"
)
[[ -n "${ALIASES[$QUERY]:-}" ]] && QUERY="${ALIASES[$QUERY]}"

# 1. mDNS multicast (LAN)
IP=$("$HOME/.local/bin/mdns-resolve" "${QUERY}.local" "$MDNS_TIMEOUT" 2>/dev/null || true)

# 2. Tailscale MagicDNS (remoto)
if [[ -z "$IP" ]]; then
    IP=$(python -c "import socket; print(socket.gethostbyname('${QUERY}.${TAILSCALE_DOMAIN}'))" 2>/dev/null || true)
fi

# 3. Cache
if [[ -z "$IP" && -f "$CACHE" ]]; then
    IP=$(grep "^${QUERY} " "$CACHE" 2>/dev/null | awk '{print $2}')
fi

if [[ -z "$IP" ]]; then
    echo "Error: no se resuelve '${HOST}'" >&2
    exit 1
fi

mkdir -p "$(dirname "$CACHE")"
grep -v "^${QUERY} " "$CACHE" > "${CACHE}.tmp" 2>/dev/null || true
echo "${QUERY} ${IP}" >> "${CACHE}.tmp"
mv "${CACHE}.tmp" "$CACHE"

echo "$IP"