#!/usr/bin/env bash
# Install Docker Engine + Compose plugin on a fresh Ubuntu 24.04 VM
# and prepare it to host a Forgejo Actions runner.
#
# Run as the target user (needs sudo). Idempotent.
set -euo pipefail

if [[ "$(. /etc/os-release && echo "$ID")" != "ubuntu" ]]; then
  echo "This script targets Ubuntu. Aborting." >&2
  exit 1
fi

echo "==> Updating apt and installing prerequisites"
sudo apt-get update -y
# arp-scan + iputils: needed by scripts/smoke-vm.sh for MAC→IP discovery
# of the test VM on the Proxmox test host (live ISO has no guest agent,
# so we scan the LAN and match on the MAC we assigned at VM creation).
sudo apt-get install -y ca-certificates curl gnupg arp-scan iputils-arping

echo "==> Adding Docker's official GPG key"
sudo install -m 0755 -d /etc/apt/keyrings
if [[ ! -f /etc/apt/keyrings/docker.asc ]]; then
  sudo curl -fsSL https://download.docker.com/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.asc
  sudo chmod a+r /etc/apt/keyrings/docker.asc
fi

echo "==> Adding Docker apt repository"
ARCH="$(dpkg --print-architecture)"
CODENAME="$(. /etc/os-release && echo "$VERSION_CODENAME")"
echo "deb [arch=${ARCH} signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/ubuntu ${CODENAME} stable" \
  | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

echo "==> Installing Docker Engine + Compose plugin"
sudo apt-get update -y
sudo apt-get install -y docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

echo "==> Adding $USER to docker group"
sudo usermod -aG docker "$USER"

echo "==> Enabling docker service"
sudo systemctl enable --now docker

echo
echo "Done. Log out and back in (or run 'newgrp docker') so group membership takes effect."
docker --version
docker compose version