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

SOURCE_ISO="${1:-}"
BACKEND="${2:-}"

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"

# shellcheck source=lib/initrd.sh
source "$REPO_DIR/scripts/lib/initrd.sh"

# Test-Device fuer den in bake_test_preseed() eingebrannten, nicht
# personalisierten Test-Preseed (Mint) - dasselbe "Default Lab"-Testgeraet,
# das schon fuer die Fedora-Verifikation genutzt wurde. Echte Personalisierung
# pro Kunde ist nicht Teil dieses Build-Skripts (siehe ADR-0011-Kontext).
TEST_DEVICE_ID="a0238a0b-d2b5-4516-a6ce-da7170041d11"
TEST_HOSTNAME="tuxflotte-mint-test"

usage() {
  echo "Usage: $0 /path/to/source.iso <fedora|mint>"
}

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

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

  case "$BACKEND" in
    fedora|mint) ;;
    *)
      echo "Error: unbekanntes Backend '$BACKEND' (erwartet: fedora oder mint)"
      exit 1
      ;;
  esac
}

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

  if [[ "$BACKEND" == "mint" ]]; then
    for cmd in jq envsubst base64 cpio; do
      if ! command -v "$cmd" >/dev/null 2>&1; then
        echo "Error: missing dependency: $cmd"
        exit 1
      fi
    done
  fi
}

prepare_dirs() {
  mkdir -p "$BUILD_DIR" "$OUTPUT_DIR"
  # xorriso extrahiert Verzeichnisse teils mit den Original-ISO-Rechten
  # (z.B. 555, kein Write-Bit) - ohne chmod schlaegt rm -rf darauf fehl.
  chmod -R u+w "$WORK_DIR" 2>/dev/null || true
  rm -rf "$WORK_DIR"
  mkdir -p "$WORK_DIR"
}

extract_iso() {
  echo "Extracting ISO..."
  xorriso -indev "$SOURCE_ISO" -osirrox on -extract / "$WORK_DIR" >/dev/null
  # xorriso uebernimmt die Original-ISO-Rechte (haeufig 555 auf
  # Verzeichnissen, 444 auf Dateien) - ohne Write-Bit koennen weder
  # spaetere Schritte (patch_grub) noch spaetere Aufraeumlaeufe
  # (prepare_dirs) Dateien darin ersetzen/entfernen.
  chmod -R u+w "$WORK_DIR"
}

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

  # -f: xorriso extrahiert ISO-Dateien mit deren Original-Rechten, die auf
  # Live-Medien haeufig read-only (444) sind - ohne -f schlaegt cp beim
  # Ueberschreiben mit "Keine Berechtigung" fehl.
  if [[ "$BACKEND" == "fedora" ]]; then
    cp -f "$REPO_DIR/grub/EFI-BOOT-grub.cfg" \
       "$WORK_DIR/EFI/BOOT/grub.cfg"

    cp -f "$REPO_DIR/grub/boot-grub2-grub.cfg" \
       "$WORK_DIR/boot/grub2/grub.cfg"
  else
    # Mint hat, anders als Fedora, keine zweite ESP/FAT-Kopie des GRUB-Menüs,
    # die separat gepatcht werden müsste (real gegen die vorhandene
    # tuxflotte-mint-test.iso verifiziert - x86_64-efi/grub.cfg ist nur ein
    # Loader-Stub, der per `source /boot/grub/grub.cfg` zurückverweist).
    cp -f "$REPO_DIR/grub/mint-boot-grub.cfg" \
       "$WORK_DIR/boot/grub/grub.cfg"

    cp -f "$REPO_DIR/grub/mint-isolinux-live.cfg" \
       "$WORK_DIR/isolinux/live.cfg"
  fi
}

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

  if [[ "$BACKEND" == "fedora" ]]; then
    grep -q "Tuxflotte" "$WORK_DIR/EFI/BOOT/grub.cfg"
    grep -q "Tuxflotte" "$WORK_DIR/boot/grub2/grub.cfg"
  else
    grep -q "Tuxflotte" "$WORK_DIR/boot/grub/grub.cfg"
    grep -q "Tuxflotte" "$WORK_DIR/isolinux/live.cfg"
  fi

  echo "GRUB verification passed."
}

bake_test_preseed() {
  [[ "$BACKEND" == "mint" ]] || return 0

  echo "Rendering test preseed (nicht personalisiert, siehe TEST_DEVICE_ID)..."

  local preseed_dir="$WORK_DIR/preseed"
  local runtime_blueprint_file="$WORK_DIR/runtime_blueprint.json"
  local server_response_file="$WORK_DIR/response.json"

  mkdir -p "$preseed_dir"

  cat > "$runtime_blueprint_file" <<EOF
{
  "runtime_blueprint": {
    "backend_id": "mint",
    "blueprints": [],
    "installation_directives": {
      "disk_encryption": false,
      "partitioning": {"scheme": "single", "root_filesystem": "ext4"},
      "secure_boot_required": false
    }
  }
}
EOF

  cat > "$server_response_file" <<EOF
{
  "device": {"hostname": "${TEST_HOSTNAME}", "id": "${TEST_DEVICE_ID}"}
}
EOF

  # backend.sh direkt wiederverwenden statt die Templating-Logik hier zu
  # duplizieren - Variablen sind bewusst nicht readonly (siehe backend.sh),
  # backend_init() wird übersprungen (braucht root für --owner/--group,
  # hier nicht nötig, mkdir reicht für den Build-Kontext).
  # shellcheck disable=SC1091
  source "$REPO_DIR/backends/mint/backend.sh"

  RUNTIME_BLUEPRINT_FILE="$runtime_blueprint_file"
  SERVER_RESPONSE_FILE="$server_response_file"
  RUNTIME_DIR="$preseed_dir"
  CONFIG_FILE="$preseed_dir/tuxflotte.seed"

  backend_validate
  backend_generate_config

  echo "Test-Preseed erzeugt: $CONFIG_FILE"
}

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"
}

patch_initrd() {
  [[ "$BACKEND" == "mint" ]] || return 0

  echo "Injecting casper-bottom updates-hook into initrd..."

  inject_casper_bottom_hooks "$REPO_DIR" \
    "$WORK_DIR/casper/initrd.lz" \
    "$WORK_DIR/casper/initrd-tuxflotte.lz"
}

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

  local output_iso
  local -a grub_map_args

  if [[ "$BACKEND" == "fedora" ]]; then
    output_iso="$OUTPUT_DIR/tuxflotte-provisioning-0.2.iso"
    grub_map_args=(
      -map "$REPO_DIR/grub/EFI-BOOT-grub.cfg" /EFI/BOOT/grub.cfg
      -map "$REPO_DIR/grub/boot-grub2-grub.cfg" /boot/grub2/grub.cfg
    )
  else
    output_iso="$OUTPUT_DIR/tuxflotte-mint-provisioning-0.1.iso"
    grub_map_args=(
      -map "$REPO_DIR/grub/mint-boot-grub.cfg" /boot/grub/grub.cfg
      -map "$REPO_DIR/grub/mint-isolinux-live.cfg" /isolinux/live.cfg
      -map "$WORK_DIR/preseed/tuxflotte.seed" /preseed/tuxflotte.seed
      -map "$WORK_DIR/casper/initrd-tuxflotte.lz" /casper/initrd.lz
    )
  fi

  rm -f "$output_iso"

  xorriso \
    -indev "$SOURCE_ISO" \
    -outdev "$output_iso" \
    -compliance no_emul_toc \
    -volid TUXFLOTTE \
    "${grub_map_args[@]}" \
    -map "$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
  bake_test_preseed
  prepare_updates
  patch_initrd
  create_iso

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

main "$@"