#!/bin/bash
# ==============================================================================
# Tailscale Exit Node Automated Setup
# ==============================================================================
# This script provisions a fresh Debian/Ubuntu VPS as a Tailscale exit node.
# It enables IP forwarding, installs Tailscale, and securely authenticates 
# the machine to your Tailnet without manual intervention.
#
# EXECUTION COMMAND:
# curl -s https://node.momo.dev.br | sudo bash -s -- tskey-auth-YOUR_KEY_HERE
# ==============================================================================

# Exit immediately if any command fails
set -e

# Ensure the script is run as root
if [ "$EUID" -ne 0 ]; then
  echo "--- Error: Please run this script as root (or using sudo) ---"
  exit 1
fi

# Ensure the Tailscale auth key was passed as an argument
if [ -z "$1" ]; then
  echo "--- Error: Missing Tailscale Auth Key! ---"
  echo "Usage: curl -s https://node.momo.dev.br | sudo bash -s -- tskey-auth-..."
  exit 1
fi

echo "--- 1. Updating package list and prerequisites ---"
apt-get update -y
apt-get install -y curl

echo "--- 2. Enabling IP Forwarding ---"
# Linux requires this to route traffic from other devices
echo 'net.ipv4.ip_forward = 1' > /etc/sysctl.d/99-tailscale.conf
echo 'net.ipv6.conf.all.forwarding = 1' >> /etc/sysctl.d/99-tailscale.conf
sysctl -p /etc/sysctl.d/99-tailscale.conf

echo "--- 3. Installing Tailscale ---"
# Runs Tailscale's official automated install script
curl -fsSL https://tailscale.com/install.sh | sh

echo "--- 4. Starting Tailscale and Advertising Exit Node ---"
# Uses the auth key passed as the first argument ($1)
tailscale up --authkey="$1" --advertise-exit-node

echo "--- Setup Complete! ---"
echo "Your VPS is now configured, authenticated, and routing traffic."