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

script_dir="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
output="${1:-${script_dir}/seed.iso}"
files=(user-data meta-data)

# Public key injected into user-data: $SSH_PUBKEY_FILE, else the first
# ~/.ssh/id_*.pub, else the first key offered by ssh-agent.
pubkey=""
if [[ -n "${SSH_PUBKEY_FILE:-}" ]]; then
  pubkey="$(head -n1 -- "${SSH_PUBKEY_FILE}")"
else
  for f in "${HOME}"/.ssh/id_ed25519.pub "${HOME}"/.ssh/id_*.pub; do
    if [[ -f "$f" ]]; then pubkey="$(head -n1 -- "$f")"; break; fi
  done
  if [[ -z "$pubkey" ]] && command -v ssh-add >/dev/null 2>&1; then
    pubkey="$(ssh-add -L 2>/dev/null | head -n1 || true)"
  fi
fi
if [[ "$pubkey" != ssh-* && "$pubkey" != ecdsa-* && "$pubkey" != sk-* ]]; then
  printf 'Error: no SSH public key found; set SSH_PUBKEY_FILE.\n' >&2
  exit 1
fi

work="$(mktemp -d)"
trap 'rm -rf -- "${work}"' EXIT
template="$(<"${script_dir}/user-data")"
printf '%s\n' "${template//@SSH_PUBKEY@/${pubkey}}" > "${work}/user-data"
cp -- "${script_dir}/meta-data" "${work}/meta-data"
if [[ -f "${script_dir}/network-config" ]]; then
  cp -- "${script_dir}/network-config" "${work}/network-config"
fi

mkdir -p "$(dirname -- "$output")"

if [[ -f "${script_dir}/network-config" ]]; then
  files+=(network-config)
fi

if command -v cloud-localds >/dev/null 2>&1; then
  args=()
  if [[ -f "${script_dir}/network-config" ]]; then
    args+=(--network-config="${work}/network-config")
  fi
  cloud-localds "${args[@]}" "${output}" \
    "${work}/user-data" "${work}/meta-data"
elif command -v xorriso >/dev/null 2>&1; then
  xorriso -as mkisofs -quiet -volid cidata -joliet -rock \
    -output "${output}" "${files[@]/#/${work}/}"
elif command -v genisoimage >/dev/null 2>&1; then
  genisoimage -quiet -output "${output}" -volid cidata -joliet -rock \
    "${files[@]/#/${work}/}"
elif command -v mkisofs >/dev/null 2>&1; then
  mkisofs -quiet -output "${output}" -volid cidata -joliet -rock \
    "${files[@]/#/${work}/}"
else
  printf 'Error: install cloud-image-utils, xorriso, genisoimage, or mkisofs.\n' >&2
  exit 1
fi

printf 'Created %s\n' "${output}"