#!/bin/bash
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 2 of the License.
#
# This program 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 General Public License for more details.

# m4_include(lib/common.sh)

source @libdir@/functions.sh

CHROOT_VERSION='v3'

RUN=''
NOCOPY='n'

working_dir=''
branch='stable'

APPNAME=$(basename "${0}")

# check for systemd running on build system
if [[ -d /run/systemd ]];then
	nosystemd=false
else
	nosystemd=true
fi

# usage: usage <exitvalue>
usage() {
	echo "Usage: ${APPNAME} [options] working-dir [package-list | app]"
	echo ' options:'
	echo '    -r <app>      Run "app" within the context of the chroot'
	echo '    -u            Update the chroot via pacman'
	echo '    -C <file>     Location of a pacman config file'
	echo '    -M <file>     Location of a makepkg config file'
	echo '    -S <file>     Location of a pacman-mirrors config file'
	echo '    -n            Do not copy config files into the chroot'
	echo '    -c <dir>      Set pacman cache'
	echo '    -b <branch>   Set repository branch'
	echo '    -x            Use classic chroot instead of systemd-nspawn'
	echo '    -h            This message'
	exit 1
}

while getopts 'r:ufnxhC:M:S:c:b:' arg; do
	case "${arg}" in
		r) RUN="$OPTARG" ;;
		u) RUN='pacman -Syu --noconfirm' ;;
		C) pac_conf="$OPTARG" ;;
		M) makepkg_conf="$OPTARG" ;;
		n) NOCOPY='y' ;;
		c) cache_dir="$OPTARG" ;;
		b) branch="$OPTARG" ;;
		S) mirrors_conf="$OPTARG" ;;
		x) nosystemd=true ;;
		h|?) usage ;;
		*) error "invalid argument '${arg}'"; usage ;;
	esac
done

if (( $EUID != 0 )); then
	die 'This script must be run as root.'
fi

shift $(($OPTIND - 1))

if [[ -z $RUN ]] && (( $# < 2 )); then
	die 'You must specify a directory and one or more packages.'
elif (( $# < 1 )); then
	die 'You must specify a directory.'
fi

working_dir="$(readlink -f ${1})"
shift 1

#WORKDIR=${working_dir}

[[ -z $working_dir ]] && die 'Please specify a working directory.'

if [[ -z $cache_dir ]]; then
	cache_dirs=($(pacman -v $cache_conf 2>&1 | grep '^Cache Dirs:' | sed 's/Cache Dirs:\s*//g'))
else
	cache_dirs=(${cache_dir})
fi

# Get host mirror
host_mirror=$(pacman -Sddp extra/devtools 2>/dev/null | sed -E "s#(.*/)(.*/)extra/.*#\1${branch}/\$repo/\$arch#")
if echo "${host_mirror}" | grep -q 'file://'; then
	host_mirror_path=$(echo "${host_mirror}" | sed -E 's#file://(/.*)/\$repo/\$arch#\1#g')
fi

# {{{ functions
build_mount_args() {
	local p
	declare -g mount_args=()

	if [[ -n $host_mirror_path ]]; then
		printf -v p '%q' "$host_mirror_path"
		mount_args+=(--bind-ro="$p")
	fi

	printf -v p '%q' "${cache_dirs[0]}"
	mount_args+=(--bind="$p")

	for cache_dir in ${cache_dirs[@]:1}; do
		printf -v p '%q' "$cache_dir"
		mount_args+=(--bind-ro="$p")
	done
}

copy_hostconf () {
	cp -a /etc/pacman.d/gnupg "${working_dir}/etc/pacman.d"
	echo "Server = ${host_mirror}" > ${working_dir}/etc/pacman.d/mirrorlist
	sed -i -e "s|^.*Branch=.*|Branch=${branch}|" ${working_dir}/etc/pacman-mirrors.conf

	if [[ -n $pac_conf && $NOCOPY = 'n' ]]; then
		cp ${pac_conf} ${working_dir}/etc/pacman.conf
	fi

	if [[ -n $makepkg_conf && $NOCOPY = 'n' ]]; then
		cp ${makepkg_conf} ${working_dir}/etc/makepkg.conf
	fi

	if [[ -n $mirrors_conf && $NOCOPY = 'n' ]]; then
		cp ${mirrors_conf} ${working_dir}/etc/pacman-mirrors.conf
		sed -i -e "s|^.*Branch=.*|Branch=${branch}|" ${working_dir}/etc/pacman-mirrors.conf
	fi

	sed -r "s|^#?\\s*CacheDir.+|CacheDir = $(echo -n ${cache_dirs[@]})|g" -i ${working_dir}/etc/pacman.conf
}

chroot_lock () {
	# Only reopen the FD if it wasn't handed to us
	if [[ $(readlink -f /dev/fd/9) != "${working_dir}.lock" ]]; then
	  exec 9>"${working_dir}.lock"
	fi

	# Lock the chroot. Take note of the FD number.
	if ! flock -n 9; then
		stat_busy "Locking chroot"
		flock 9
		stat_done
	fi
}

# track_mount() {
# 	if [[ -z $CHROOT_ACTIVE_MOUNTS ]]; then
# 	  CHROOT_ACTIVE_MOUNTS=()
# 	  trap 'chroot_umount' EXIT
# 	fi
#
# 	mount "$@" && CHROOT_ACTIVE_MOUNTS=("$2" "${CHROOT_ACTIVE_MOUNTS[@]}")
# }
#
# mount_conditionally() {
# 	local cond=$1; shift
# 	if eval "$cond"; then
# 	  track_mount "$@"
# 	fi
# }
#
# api_fs_mount_build() {
# 	mount_conditionally "! mountpoint -q '$1'" "$1" "$1" --bind &&
# 	track_mount proc "$1/proc" -t proc -o nosuid,noexec,nodev &&
# 	track_mount sys "$1/sys" -t sysfs -o nosuid,noexec,nodev,ro &&
# 	track_mount udev "$1/dev" -t devtmpfs -o mode=0755,nosuid &&
# 	track_mount devpts "$1/dev/pts" -t devpts -o mode=0620,gid=5,nosuid,noexec &&
# 	track_mount shm "$1/dev/shm" -t tmpfs -o mode=1777,nosuid,nodev &&
# 	track_mount run "$1/run" -t tmpfs -o nosuid,nodev,mode=0755 &&
# 	track_mount tmp "$1/tmp" -t tmpfs -o mode=1777,strictatime,nodev,nosuid
# 	track_mount /etc/resolv.conf "$1/etc/resolv.conf" --bind
# 	track_mount ${cache_dirs[0]} "$1/${cache_dirs[0]}" --bind
# }
#
# chroot_umount() {
# 	umount "${CHROOT_ACTIVE_MOUNTS[@]}"
# }

chroot_run() {
	local dir=$1
	shift
	if ${nosystemd};then
		chroot "${dir}" "${@}"
	else
		systemd-nspawn -D "${dir}" "${mount_args[@]}" -- ${@} 2>/dev/null
	fi
}

# }}}

umask 0022

if [[ -n $RUN ]]; then
	# run chroot {{{
	#Sanity check
	if [[ ! -f "${working_dir}/.manjaro-chroot" ]]; then
		die "'${working_dir}' does not appear to be a Manjaro chroot."
	elif [[ $(cat "${working_dir}/.manjaro-chroot") != ${CHROOT_VERSION} ]]; then
		die "'${working_dir}' is not compatible with ${APPNAME} version ${CHROOT_VERSION}. Please rebuild."
	fi

	chroot_lock
	if ${nosystemd};then
		api_fs_mount "${working_dir}"
		track_mount /etc/resolv.conf "${working_dir}/etc/resolv.conf" --bind
		track_mount ${cache_dirs[0]} "${working_dir}/${cache_dirs[0]}" --bind
	else
		build_mount_args
	fi
	copy_hostconf

	chroot_run "${working_dir}" ${RUN}

	# }}}
else
	# {{{ build chroot
	if [[ -e $working_dir ]]; then
		die "Working directory '${working_dir}' already exists"
	fi

	mkdir -p "${working_dir}"

	if [[ "$(stat -f -c %T "${working_dir}")" == btrfs ]]; then
		rmdir "${working_dir}"
		if ! btrfs subvolume create "${working_dir}"; then
			die "Couldn't create subvolume for '${working_dir}'"
		fi
		chmod 0755 "${working_dir}"
	fi

	chroot_lock

	pacargs=("${cache_dirs[@]/#/--cachedir=}")
	if [[ -n $pac_conf ]]; then
		pacargs+=("--config=${pac_conf}")
	fi

	if ! basestrap -GMcd "${working_dir}" "${pacargs[@]}" "$@"; then
		die 'Failed to install all packages'
	fi

	printf '%s.UTF-8 UTF-8\n' en_US de_DE > "${working_dir}/etc/locale.gen"
	chroot_run "${working_dir}" locale-gen
	echo 'LANG=C' > "${working_dir}/etc/locale.conf"

	copy_hostconf

	echo "${CHROOT_VERSION}" > "${working_dir}/.manjaro-chroot"
	# }}}
fi