#!/bin/bash

interface=$(ip -o link |
  awk '{print $2}' |
  cut -d ':' -f 1 |
  cut -d '@' -f 1 |
  grep -v -w 'lo' |
  head -1)
ipaddress=$(ip addr show "${interface}" |
  grep -o -E "([0-9]{1,3}[\.]){3}[0-9]{1,3}/[0-9]{2}")
gateway=$(ip route show | awk '/default/ {print $3}')
hostname="pivpn.test"

err() {
  echo "[$(date +'%Y-%m-%dT%H:%M:%S%z')]: $*" >&2
}

common() {
  sed -i "s/INTERFACE/${interface}/g" "${vpnconfig}"
  sed -i "s|IPADDRESS|${ipaddress}|g" "${vpnconfig}"
  sed -i "s/GATEWAY/${gateway}/g" "${vpnconfig}"
}

openvpn() {
  vpnconfig="ciscripts/ci_openvpn.conf"
  twofour=1
  common
  sed -i "s/2POINT4/${twofour}/g" "${vpnconfig}"
  cat "${vpnconfig}"
  exit 0
}

wireguard() {
  vpnconfig="ciscripts/ci_wireguard.conf"
  common
  cat "${vpnconfig}"
  exit 0
}

if [[ "$#" -lt 1 ]]; then
  err "specifiy a VPN protocol to prepare"
  exit 1
else
  chmod +x auto_install/install.sh
  sudo hostnamectl set-hostname "${hostname}"
  cat /etc/os-release

  while true; do
    case "${1}" in
      -o | --openvpn)
        openvpn
        ;;
      -w | --wireguard)
        wireguard
        ;;
      *)
        err "unknown vpn protocol"
        exit 1
        ;;
    esac
  done
fi