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

SOURCE_ISO="${1:-}"

REPO_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
BASE_DIR="$(cd "$REPO_DIR/.." && pwd)"
BUILD_DIR="$BASE_DIR/build"
WORK_DIR="$BUILD_DIR/work"
OUTPUT_DIR="$BUILD_DIR/output"

usage() {
  echo "Usage: $0 /path/to/source.iso"
}

check_input() {
  if [[ -z "$SOURCE_ISO" ]]; then
    usage
    exit 1
  fi

  if [[ ! -f "$SOURCE_ISO" ]]; then
    echo "Error: ISO not found: $SOURCE_ISO"
    exit 1
  fi
}

check_dependencies() {
  for cmd in xorriso; do
    if ! command -v "$cmd" >/dev/null 2>&1; then
      echo "Error: missing dependency: $cmd"
      exit 1
    fi
  done
}

prepare_dirs() {
  mkdir -p "$BUILD_DIR" "$OUTPUT_DIR"
  rm -rf "$WORK_DIR"
  mkdir -p "$WORK_DIR"
}

extract_iso() {
  echo "Extracting ISO..."
  xorriso -indev "$SOURCE_ISO" -osirrox on -extract / "$WORK_DIR" >/dev/null
}

patch_grub() {
  echo "Installing Tuxflotte GRUB configuration..."

  cp "$REPO_DIR/grub/EFI-BOOT-grub.cfg" \
     "$WORK_DIR/EFI/BOOT/grub.cfg"

  cp "$REPO_DIR/grub/boot-grub2-grub.cfg" \
     "$WORK_DIR/boot/grub2/grub.cfg"
}

verify_workdir() {
  echo "Verifying workdir..."

  grep -q "Tuxflotte" "$WORK_DIR/EFI/BOOT/grub.cfg"
  grep -q "Tuxflotte" "$WORK_DIR/boot/grub2/grub.cfg"

  echo "GRUB verification passed."
}

prepare_updates() {
  echo "Assembling live-updates payload..."

  local updates_dir="$WORK_DIR/updates"

  rm -rf "$updates_dir"
  mkdir -p "$updates_dir/opt/tuxflotte"

  cp -a "$REPO_DIR/live-updates/." "$updates_dir/"
  cp -a "$REPO_DIR/scripts" "$updates_dir/opt/tuxflotte/"
  cp -a "$REPO_DIR/backends" "$updates_dir/opt/tuxflotte/"
  cp -a "$REPO_DIR/config" "$updates_dir/opt/tuxflotte/"

  chmod 0440 "$updates_dir/etc/sudoers.d/90-tuxflotte"
}

create_iso() {
  echo "Creating Tuxflotte ISO..."

  local output_iso="$OUTPUT_DIR/tuxflotte-provisioning-0.2.iso"

  rm -f "$output_iso"

  xorriso \
    -indev "$SOURCE_ISO" \
    -outdev "$output_iso" \
    -compliance no_emul_toc \
    -volid TUXFLOTTE \
    -map "$REPO_DIR/grub/EFI-BOOT-grub.cfg" /EFI/BOOT/grub.cfg \
    -map "$REPO_DIR/grub/boot-grub2-grub.cfg" /boot/grub2/grub.cfg \
    -map "$WORK_DIR/updates" /updates \
    -chown_r 0 /updates -- \
    -chgrp_r 0 /updates -- \
    -boot_image any replay

  echo "ISO created: $output_iso"
}

main() {
  check_input
  check_dependencies
  prepare_dirs
  extract_iso
  patch_grub
  verify_workdir
  prepare_updates
  create_iso

  echo
  echo "Build complete."
  echo "Work dir: $WORK_DIR"
}

main "$@"