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

MAC="52:54:00:12:34:56"
IP_CIDR="100.100.0.2/24"
GW="100.100.0.1"
DNS1="8.8.8.8"
DNS2="1.1.1.1"

backup_dir="/etc/netplan/backup-$(date +%Y%m%d-%H%M%S)"
mkdir -p "$backup_dir"

# Back up all current netplan YAMLs
cp -a /etc/netplan/*.yaml "$backup_dir"/ 2>/dev/null || true

# Move any NetworkManager-generated netplan snippets out of the way
if ls /etc/netplan/90-NM-*.yaml >/dev/null 2>&1; then
  mv /etc/netplan/90-NM-*.yaml "$backup_dir"/ || true
fi

cat > /etc/netplan/00-installer-config.yaml <<EOF
network:
  version: 2
  ethernets:
    lan0:
      match:
        macaddress: ${MAC}
      set-name: ens3
      dhcp4: false
      addresses:
        - ${IP_CIDR}
      routes:
        - to: default
          via: ${GW}
      nameservers:
        addresses:
          - ${DNS1}
          - ${DNS2}
EOF

chmod 600 /etc/netplan/*.yaml 2>/dev/null || true

netplan generate
netplan apply

sleep 2

echo "==== Interfaces (ens3/ens4) ===="
ip -br a | grep -E '^(ens3|ens4)\b' || true

echo "==== Routes ===="
ip route | sed -n '1,10p'

echo "==== Ping ===="
ping -c 1 -W 2 1.1.1.1