#!/bin/bash

#
# template script for generating Void Linux container for LXC
#

#
# lxc: linux Container library

# Authors:
# Gregor Reitzenstein <dean4devil@paranoidlabs.org>

# Based on lxc-archlinux template by:
# Alexander Vladimirov <alexander.idkfa.vladimirov@gmail.com>
# John Lane <lxc@jelmail.com>

# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.

# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.

# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

# Utility functions

# Check if array $2 contains item $1
containsElement() {
	local e
	for e in "${@:2}"; do [[ "$1" == "$e" ]] && return 0; done
	return 1
}

# split comma-separated string into an array
# ${1} - string to split
# ${2} - separator (default is ",")
# ${result} - result value on success
split_string() {
    local ifs=${IFS}
    IFS="${2:-,}"
    read -ra result < <(echo "${1}")
    IFS=${ifs}
    return 0
}

# Make sure the usual locations are in PATH
export PATH=$PATH:/usr/sbin:/usr/bin:/sbin:/bin

# defaults
default_path="/var/lib/lxc"
default_path="@LXCPATH@"
shared_config="@LXCTEMPLATECONFIG@/voidlinux.common.conf"
userns_config="@LXCTEMPLATECONFIG@/voidlinux.userns.conf"

pkg_blacklist=("linux>=0" "e2fsprogs>=0" "btrfs-progs>=0" "xfsprogs>=0" "f2fs-tools>=0" "dosfstools>=0")
base_packages=()
for pkg in $(xbps-query -Mv --repository="http://repo2.voidlinux.eu/current/" -x base-system); do
    containsElement "$pkg" "${pkg_blacklist[@]}" || base_packages+=($pkg)
done
declare -a additional_packages

copy_configuration() {
    mkdir -p "${config_path}"
    local config="${config_path}/config"
    echo "lxc.utsname = ${name}" >> "${config}"
    grep -q "^lxc.rootfs" "${config}" 2>/dev/null \
        || echo "lxc.rootfs = ${rootfs_path}" >> "${config}"

    # Detect if were in a UserNS and include the right config
    if [ -z "${LXC_MAPPED_GID+x}" ] || [ -z "${LXC_MAPPED_UID+x}" ]; then
        echo "lxc.include = ${userns_config}" >> "${config}"
    else
        echo "lxc.include = ${shared_config}" >> "${config}"
    fi

    if [ $? -ne 0 ]; then
        echo "Failed to configure container"
        return 1
    fi
    return 0
}

install_void() {
    if ! yes | xbps-install -Sy -R http://repo2.voidlinux.eu/current -r "${rootfs_path}" "${base_packages[@]}"
    then
        echo "Failed to install container packages"
        return 1
    fi
}

usage() {
     cat <<EOF
usage:
    ${1} -n|--name=<container_name> [-p|--path=<path>] [-a|--arch=<arch of the container>]
        [-r|--root_password=<root password>] [-P|--packages=<pkg1,pkg2,...>] [-h|--help]

Mandatory args:
  -n,--name           container name, used to as an identifier for that container from now on
Optional args:
  -p,--path           path to where the container rootfs will be created (${default_path})
  --rootfs            path for actual container rootfs, (${default_path}/rootfs)
  -P,--packages       preinstall additional packages, comma-separated list
  -c,--config         use specified pacman config when installing container packages
  -a,--arch           use specified architecture instead of host's architecture
  -r,--root_password  set container root password
  -h,--help           print this help
EOF
    return 0
}

options=$(getopt -o hp:P:n:c:r: -l help,rootfs:,path:,packages:,name:,config:,root_password:,mapped-uid:,mapped-gid: -- "${@}")
if [ ${?} -ne 0 ]; then
    usage "$(basename "${0}")"
    exit 1
fi
eval set -- "${options}"

while true
do
    case "${1}" in
    -h|--help)          usage "${0}" && exit 0;;
    -p|--path)          path=${2}; shift 2;;
    -n|--name)          name=${2}; shift 2;;
    -c|--config)        config_path=${2}; shift 2;;
    --rootfs)           rootfs_path=${2}; shift 2;;
    -P|--packages)      additional_packages=${2}; shift 2;;
    -r|--root_password) root_passwd=${2}; shift 2;;
    --mapped-uid)       LXC_MAPPED_UID=$2; shift 2;;
    --mapped-gid)       LXC_MAPPED_GID=$2; shift 2;;
    --)             shift 1; break ;;
    *)              break ;;
    esac
done

if [ -z "${name}" ]; then
    echo "missing required 'name' parameter"
    exit 1
fi

type xbps-install >/dev/null 2>&1
if [ ${?} -ne 0 ]; then
    echo "'xbps-install' command is missing."
fi
type xbps-query >/dev/null 2>&1
if [ ${?} -ne 0 ]; then
    echo "'xbps-query' command is missing."
fi

if [ -z "${rootfs_path}" ]; then
    rootfs_path="${path}/rootfs"
fi
config_path="${path}"

revert() {
    echo "Interrupted, cleaning up"
    lxc-destroy -n "${name}"
    rm -rf "${path:?}/${name}"
    rm -rf "${default_path:?}/${name}"
    exit 1
}
trap revert SIGHUP SIGINT SIGTERM

copy_configuration
if [ $? -ne 0 ]; then
    echo "Failed to write configuration file"
    rm -rf "${config_path}"
    exit 1
fi

if [ ${#additional_packages[@]} -gt 0 ]; then
    split_string "${additional_packages}"
    base_packages+=(${result[@]})
fi

mkdir -p "${rootfs_path}"
install_void
if [ ${?} -ne 0 ]; then
    echo "Failed to install Void Linux"
    rm -rf "${config_path}" "${path}"
    exit 1
fi



if [ -n "${root_passwd}" ]; then
    echo "root:${root_passwd}" | chroot "${rootfs_path}" chpasswd
fi

cat << EOF
Void Linux Container ${name} has been successfully created. The configuration is
stored in ${config_path}/config. Please refer to https://wiki.voidlinux.eu for
information regarding Void Linux.
EOF
