#!/usr/bin/env /bin/bash
declare -r BASEDIR="`pwd`"

declare -r mode="full"	# one of 'full'|'unattend'

declare -r ISO_BASEDIR="/mnt/machines/iso"
declare -r CONFIG_DIR="${BASEDIR}/configs"

declare -r UNATTEND_XML="${2:-"${CONFIG_DIR}/autounattend-builder-amd64-20260527.xml"}"

#declare -r WINDOWS_ISO="${ISO_BASEDIR}/nano11-25H2-Pro-Eng-Arm64-20260513.iso"
#declare -r WINDOWS_ISO="${ISO_BASEDIR}/tiny11-25H2-Pro-Eng-Arm64-20260514.iso"
#declare -r WINDOWS_ISO="${ISO_BASEDIR}/nano11-25H2-English-Pro-2026-03-15.iso"
#declare -r WINDOWS_ISO="${ISO_BASEDIR}/Tiny11-25H2-English-Pro-2026-05-20.iso"
#declare -r WINDOWS_ISO="${ISO_BASEDIR}/Tiny11Core-25H2-English-Pro-2026-05-20.iso"
#declare -r WINDOWS_ISO="${ISO_BASEDIR}/nano11-25H2-English-Pro-2026-05-20.iso"

#declare -r WINDOWS_ISO="${ISO_BASEDIR}/nano11-base-25H2-Pro-Eng-amd64-20260526.iso"
declare -r WINDOWS_ISO="${ISO_BASEDIR}/nano11-base-25H2-Pro-Eng-arm64-20260526.iso"

declare -r VIRTIO_ISO="${ISO_BASEDIR}/virtio-win-0.1.285.iso"
#declare -r VIRTIO_ISO="${BASEDIR}/virtio-win-0.1.285.iso"


######################################################################################
#
#

function detect_iso_arch {
	local iso_file="${1}"
	local fallback_arch="${2}"
	case "${iso_file@L}" in
	*-amd64-*|*-x64-*)
		echo "amd64" ;;
	*-arm64-*|*-aarch64-*)
		echo "arm64" ;;
	*)	# Unknown use host arch as fallback
		echo "NOTICE: Cannot detect architecture from ISO name, using fallback" >&2
		echo "${fallback_arch}" ;;
	esac
}

function detect_host_arch {
	case "$(uname -m | tr '[:upper:]' '[:lower:]')" in
	"x86_64")  echo "amd64" ;;
	"aarch64") echo "arm64" ;;
	*) return 1 ;;
	esac
}

######################################################################################
# Detect host and guest architecture
declare -r HOST_ARCH="$(detect_host_arch)"
[[ -n "${HOST_ARCH}" ]] || {
	echo "Failed to detect host arch" >&2;
	exit 1;
}

declare -r TARGET_ARCH="$(detect_iso_arch "${WINDOWS_ISO}")"
[[ -n "${TARGET_ARCH}" ]] || {
	echo "Failed to detect target arch" >&2;
	exit 1;
}

case "${mode}" in
"full")
	echo "Generating full ${TARGET_ARCH} installation ISO image..." >&2
	declare -r DEFAULT_OUTPUT_FILE="install-${TARGET_ARCH}-$(date +%Y%m%d-%H%M00).iso"
	;;
"unattend")
	echo "Generating unattended ${TARGET_ARCH} ISO image..." >&2
	declare -r DEFAULT_OUTPUT_FILE="unattend-${TARGET_ARCH}-$(date +%Y%m%d-%H%M00).iso"
	;;
*)
	echo "Invalid mode '${mode}' expected either 'full'|'unattend'" >&2
	exit 1
	;;
esac



#
# Output file
#
declare -r OUTPUT_FILE="${1:-${DEFAULT_OUTPUT_FILE}}"


#
# Validate input XML
#
xmllint -noout "${UNATTEND_XML}" || {
	echo "$(basename "${UNATTEND_XML}") contains invalid XML, aborting" >&2
	exit 1
}


mkdir -p "${BASEDIR}/build"  || exit $?
mkdir -p "${BASEDIR}/output" || exit $?

# Convert architecture for virtio installation media
case "${TARGET_ARCH}" in
"arm64")
	VIRTIO_ARCH="${TARGET_ARCH@U}" ;;	# Virtio ISO uses "ARM64"
*)
	VIRTIO_ARCH="${TARGET_ARCH}" ;;		# Virtio ISO uses "amd64"
esac


#
# Generate builder script
#
cat -> "${BASEDIR}/build/genimage-${TARGET_ARCH}.sh" <<-EOF
	#!/usr/bin/env /bin/ash

	#
	# Required packages
	#
	echo "Installing required packages..." >&2
	apk update || exit \$?
	apk add xorriso 7zip || exit \$?

	#
	# Prepare directories / mountpoints
	#
	echo "Preparing build directory and mountpoints..." >&2
	mkdir -p /tmp/base   || exit \$?
	mkdir -p /tmp/virtio || exit \$?
	mkdir -p /tmp/build  || exit \$?

	#
	# Mounting (if possible) / unpacking of ISO images
	#
	if [[ "x${mode}" == "xfull" ]]; then
		echo "Attempting to mount windows ISO image..." >&2
		mount -t udf -o loop,ro /input/windows.iso /tmp/base/ 2>/dev/null || {
			echo "Unpacking windows ISO image (fallback)..." >&2
			7z x -bb0 -o/tmp/base/ /input/windows.iso || exit \$?
		}
	else
		echo "Building unattend ISO image, skipping windows mount" >&2
	fi

	echo "Attempting to mount virtio-win ISO image..." >&2
	mount -o loop,ro /input/virtio.iso /tmp/virtio/ 2>/dev/null || {
		echo "Unpacking virtio-win ISO image (fallback)..." >&2
		7z x -bb0 -o/tmp/virtio/ /input/virtio.iso || exit \$?
	}

	#
	# Autounattend XML configuration file (replaces any existing one)
	#
	echo "Copying autounattend.xml..." >&2
	sed -e 's|processorArchitecture="[^"]\+"|processorArchitecture="${TARGET_ARCH}"|' \
		< /input/autounattend.xml \
		> /tmp/build/autounattend.xml || exit \$?

	#
	# Required drivers for installation (into "$WinPEDriver$")
	#
	echo "Creating \\\$WinPEDriver\\\$..." >&2
	mkdir -p "/tmp/build/\\\$WinPEDriver\\\$" || exit \$?
	for x in NetKVM viostor vioscsi; do
		cp -vfR /tmp/virtio/\${x}/w11/${VIRTIO_ARCH} "/tmp/build/\\\$WinPEDriver\\\$/\${x}" || exit \$?
	done

	#
	# OEM files (drivers, packages, etc.)
	#
	echo "Copying OEM files..." >&2

	mkdir -p \
		"/tmp/build/\\\$OEM\\\$/\\\$\\\$" \
		"/tmp/build/\\\$OEM\\\$/\\\$1" \
		|| exit \$?

	# Viofs files for use in the final OS (virtiofsd)
	mkdir -p "/tmp/build/\\\$OEM\\\$/\\\$1/drivers" || exit \$?
	for x in /tmp/virtio/viofs/w11/${VIRTIO_ARCH}; do
		drvname="\$(echo "\${x}" | cut -d'/' -f4)" || exit \$?
		cp -vfR "\${x}" "/tmp/build/\\\$OEM\\\$/\\\$1/drivers/\${drvname}" || exit \$?
	done

	#
	# Virtio drivers for auto-installation
	#
	echo "Copying virtio drivers for automatic installation..." >&2

	mkdir -p "/tmp/build/drivers" || exit \$?
	for x in /tmp/virtio/*/w11/${VIRTIO_ARCH}; do
		drvname="\$(echo "\${x}" | cut -d'/' -f4)" || exit \$?
		cp -vfR "\${x}" "/tmp/build/drivers/\${drvname}" || exit \$?
	done

	#
	# ISO image generation
	#
	if [[ "x${mode}" == "xfull" ]]; then
		echo "Generating ISO boot image..." >&2
		mkisofs \\
			-quiet \\
			-b boot/etfsboot.com \\
			-no-emul-boot \\
			-boot-load-size 8 \\
			-iso-level 3 -J -l -D -N -U -joliet-long -relaxed-filenames -rational-rock \\
			-eltorito-alt-boot -e efi/microsoft/boot/efisys_noprompt.bin -no-emul-boot \\
			-m "/tmp/base/autounattend.xml" \\
			-V "Nano11-Builder" \\
			-o "/output/$(basename "${OUTPUT_FILE}")" \\
			"/tmp/base/" "/tmp/build/" || exit \$?
	else
		echo "Generating ISO unattend image..." >&2
		mkisofs \\
			-quiet \\
			-iso-level 3 -J -l -D -N -U -joliet-long -relaxed-filenames -rational-rock \\
			-V "Nano11-Builder-Unattend" \\
			-o "/output/$(basename "${OUTPUT_FILE}")" \\
			"/tmp/build/" || exit \$?
	fi

#	genisoimage \\
#		-quiet \\
#		-b boot/etfsboot.com \\
#		-no-emul-boot \\
#		-boot-load-seg 1984 \\
#		-boot-load-size 8 \\
#		-iso-level 3 -J -l -D -N -U -joliet-long -allow-limited-size -relaxed-filenames -rock \\
#		-eltorito-alt-boot -e efi/microsoft/boot/efisys_noprompt.bin \\
#		-m "/tmp/base/autounattend.xml" \\
#		-V "Nano11-Builder" \\
#		-o "/build/output.iso" \\
#		"/tmp/base/" "/tmp/build/" || exit \$?

	#
	#
	#
	echo "Cleaning up..." >&2
	umount /tmp/base/   2>/dev/null
	umount /tmp/virtio/ 2>/dev/null
EOF

chmod 0755 "${BASEDIR}/build/genimage-${TARGET_ARCH}.sh" || exit $?

declare -r CONTAINER_IMAGE="alpine:3.23"
declare -r CONTAINER_ARGS=(
	"-it --rm --name isobuilder-${TARGET_ARCH}"
	"-v ${VIRTIO_ISO}:/input/virtio.iso:ro,Z"
	"-v ${WINDOWS_ISO}:/input/windows.iso:ro,Z"
	"-v ${UNATTEND_XML}:/input/autounattend.xml:ro,Z"
	"-v ${BASEDIR}/build:/build:ro,Z"
	"-v ${BASEDIR}/output:/output:rw,Z"
	"--privileged --network host"
)

#
# Run generation script in alpine 3.23 container
#
if type -p docker &>/dev/null; then
	echo "Running isobuilder in docker container" >&2
	docker run ${CONTAINER_ARGS[@]} ${CONTAINER_IMAGE} \
		/build/genimage-${TARGET_ARCH}.sh || exit $?
elif type -p podman &>/dev/null; then
	echo "Running isobuilder in podman container" >&2
	podman run ${CONTAINER_ARGS[@]} ${CONTAINER_IMAGE} \
		/build/genimage-${TARGET_ARCH}.sh || exit $?
else
	echo "Failed to start build container: no runtime available" >&2
	exit 1
fi

(cd "${BASEDIR}/output" && ls -sh "$(basename "${OUTPUT_FILE}")") || exit $?