#!/usr/bin/env bash
# ssh-mdns-proxy: Resolve .local via mDNS with fallbacks, then connect
#
# Resolution order: mDNS → Tailscale DNS → cached IP
# Usage: ssh-mdns-proxy <hostname> [port]
#
# Configure your Tailscale domain:
TAILSCALE_DOMAIN="${TAILSCALE_DOMAIN:-tailb0bb74.ts.net}"

HOST="$1"
PORT="${2:-22}"
CACHE="$HOME/.ssh/mdns-cache"
QUERY="${HOST%.local}"

# Alias mapping (short name -> mDNS hostname)
declare -A ALIASES=(
    [dell]="dell-latitude3400"
    [lenovo]="lenovo-ideapad"
)
[[ -n "${ALIASES[$QUERY]}" ]] && QUERY="${ALIASES[$QUERY]}"

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"

# 1. mDNS resolution
IP=$("$SCRIPT_DIR/mdns-resolve" "${QUERY}.local" 2 2>/dev/null)

# 2. Fallback: Tailscale DNS (Termux carece de getent, usar python si esta disponible)
if [[ -z "$IP" ]]; then
    if command -v getent >/dev/null 2>&1; then
        IP=$(getent hosts "${QUERY}.${TAILSCALE_DOMAIN}" 2>/dev/null | awk '{print $1}')
    else
        IP=$(python -c "import socket; print(socket.gethostbyname('${QUERY}.${TAILSCALE_DOMAIN}'))" 2>/dev/null)
    fi
fi

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

if [[ -z "$IP" ]]; then
    echo "Error: cannot resolve ${HOST}" >&2
    exit 1
fi

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

exec nc "$IP" "$PORT"