#!/bin/bash

set -e
set -o pipefail

machine=$(uname -m)

case ${machine} in
	aarch64 )
		TOOLBOX_DOCKER_IMAGE=arm64v8/fedora
		TOOLBOX_DOCKER_TAG=latest
		;;
	x86_64 )
		TOOLBOX_DOCKER_IMAGE=fedora
		TOOLBOX_DOCKER_TAG=latest
		;;
	* )
		echo "Warning: Unknown machine type ${machine}" >&2
		;;
esac

TOOLBOX_USER=root
TOOLBOX_DIRECTORY="/var/lib/toolbox"
TOOLBOX_BIND="--bind=/:/media/root --bind=/usr:/media/root/usr --bind=/run:/media/root/run"
# Ex: "--setenv=KEY=VALUE"
TOOLBOX_ENV=""

toolboxrc="${HOME}"/.toolboxrc

# System defaults
if [ -f "/etc/default/toolbox" ]; then
	source "/etc/default/toolbox"
fi

# User overrides
if [ -f "${toolboxrc}" ]; then
	source "${toolboxrc}"
fi

if [[ -n "${TOOLBOX_DOCKER_IMAGE}" ]] && [[ -n "${TOOLBOX_DOCKER_TAG}" ]]; then
	TOOLBOX_NAME=${TOOLBOX_DOCKER_IMAGE}-${TOOLBOX_DOCKER_TAG}
	have_docker_image="y"
fi

machinename=$(echo "${USER}-${TOOLBOX_NAME}" | sed -r 's/[^a-zA-Z0-9_.-]/_/g')
machinepath="${TOOLBOX_DIRECTORY}/${machinename}"
osrelease="${machinepath}/etc/os-release"
if [ ! -f "${osrelease}" ] || systemctl is-failed -q "${machinename}" ; then
	sudo mkdir -p "${machinepath}"
	sudo chown "${USER}:" "${machinepath}"

	if [[ -n "${have_docker_image}" ]]; then
		riid=$(sudo --preserve-env rkt --insecure-options=image fetch "docker://${TOOLBOX_DOCKER_IMAGE}:${TOOLBOX_DOCKER_TAG}")
		sudo --preserve-env rkt image extract --overwrite --rootfs-only "${riid}" "${machinepath}"
		sudo --preserve-env rkt image rm "${riid}"
	elif [[ -n "${TOOLBOX_DOCKER_ARCHIVE}" ]]; then
		tmpdir=$(mktemp -d -p /var/tmp/)
		trap "sudo rm -rf ${tmpdir}" EXIT PIPE
		wget -O- "${TOOLBOX_DOCKER_ARCHIVE}" | xz -cd | tar -C ${tmpdir} -xf -
		layer=$(find ${tmpdir} -name layer.tar -type f)
		sudo tar -C ${machinepath} -xf ${layer}
		trap - EXIT PIPE
		sudo rm -rf ${tmpdir}
	else
		echo "Error: No toolbox filesystem specified." >&2
		exit 1
	fi
	sudo touch "${osrelease}"
fi

# Special case for when SSH tries to pass a shell command with -c
if [ "x${1-}" == x-c ]; then
	set /bin/sh "$@"
fi

sudo SYSTEMD_NSPAWN_SHARE_SYSTEM=1 systemd-nspawn \
	--directory="${machinepath}" \
	--capability=all \
        ${TOOLBOX_BIND} \
        ${TOOLBOX_ENV} \
	--user="${TOOLBOX_USER}" "$@"