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

log() {
  printf '[make-rootfs] %s\n' "$*"
}

usage() {
  cat <<'EOF'
Usage: ./make-rootfs.sh [--size <size>] [--base-rootfs <path>]

Builds rootfs-docker.ext4 using customize.sh. If --base-rootfs is omitted,
the first existing file is used:
  ./rootfs.ext4
  ./ubuntu-noble-rootfs/rootfs.ext4
  ./ubuntu-lts/rootfs.ext4
EOF
}

DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
OUT_ROOTFS="$DIR/rootfs-docker.ext4"
SIZE_SPEC="6G"
BASE_ROOTFS=""

while [[ $# -gt 0 ]]; do
  case "$1" in
    --size)
      SIZE_SPEC="${2:-}"
      shift 2
      ;;
    --base-rootfs)
      BASE_ROOTFS="${2:-}"
      shift 2
      ;;
    -h|--help)
      usage
      exit 0
      ;;
    *)
      log "unknown option: $1"
      usage
      exit 1
      ;;
  esac
done

if [[ -f "$OUT_ROOTFS" ]]; then
  log "already exists: $OUT_ROOTFS"
  exit 0
fi

if [[ -z "$BASE_ROOTFS" ]]; then
  if [[ -f "$DIR/rootfs.ext4" ]]; then
    BASE_ROOTFS="$DIR/rootfs.ext4"
  elif [[ -f "$DIR/ubuntu-noble-rootfs/rootfs.ext4" ]]; then
    BASE_ROOTFS="$DIR/ubuntu-noble-rootfs/rootfs.ext4"
  elif [[ -f "$DIR/ubuntu-lts/rootfs.ext4" ]]; then
    BASE_ROOTFS="$DIR/ubuntu-lts/rootfs.ext4"
  else
    log "no base rootfs found"
    exit 1
  fi
fi

log "building $OUT_ROOTFS from $BASE_ROOTFS"
exec "$DIR/customize.sh" "$OUT_ROOTFS" \
  --size "$SIZE_SPEC" \
  --base-rootfs "$BASE_ROOTFS" \
  --docker