#!/bin/bash
# License: GNU GPLv2
#
# 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)
m4_include(lib/archroot.sh)

working_dir=''

files=()

usage() {
	echo "Usage: ${0##*/} [options] working-dir [systemd-nspawn arguments]"
	echo "A wrapper around systemd-nspawn. Provides support for pacman."
	echo
	echo ' options:'
	echo '    -C <file>     Location of a pacman config file'
	echo '    -M <file>     Location of a makepkg config file'
	echo '    -c <dir>      Set pacman cache'
	echo '    -f <file>     Copy file from the host to the chroot'
	echo '    -s            Do not run setarch'
	echo '    -h            This message'
	exit 1
}

while getopts 'hC:M:c:f:s' arg; do
	case "$arg" in
		C) pac_conf="$OPTARG" ;;
		M) makepkg_conf="$OPTARG" ;;
		c) cache_dir="$OPTARG" ;;
		f) files+=("$OPTARG") ;;
		s) nosetarch=1 ;;
		h|?) usage ;;
		*) error "invalid argument '%s'" "$arg"; usage ;;
	esac
done
shift $((OPTIND - 1))

(( $# < 1 )) && die 'You must specify a directory.'
check_root

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

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

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

# shellcheck disable=2016
host_mirror=$(pacman --cachedir /doesnt/exist -Sddp extra/devtools 2>/dev/null | sed -r 's#(.*/)extra/os/.*#\1$repo/os/$arch#')
# shellcheck disable=2016
[[ $host_mirror == *file://* ]] && host_mirror_path=$(echo "$host_mirror" | sed -r 's#file://(/.*)/\$repo/os/\$arch#\1#g')

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

	if [[ -n $host_mirror_path ]]; then
		mount_args+=("--bind-ro=$host_mirror_path")
	fi

	mount_args+=("--bind=${cache_dirs[0]}")

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

copy_hostconf () {
	cp -a /etc/pacman.d/gnupg "$working_dir/etc/pacman.d"
	echo "Server = $host_mirror" >"$working_dir/etc/pacman.d/mirrorlist"

	[[ -n $pac_conf ]] && cp "$pac_conf" "$working_dir/etc/pacman.conf"
	[[ -n $makepkg_conf ]] && cp "$makepkg_conf" "$working_dir/etc/makepkg.conf"

	local file
	for file in "${files[@]}"; do
		mkdir -p "$(dirname "$working_dir$file")"
		cp -T "$file" "$working_dir$file"
	done

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

umask 0022

# Sanity check
if [[ ! -f "$working_dir/.arch-chroot" ]]; then
	die "'%s' does not appear to be an Arch chroot." "$working_dir"
elif [[ $(cat "$working_dir/.arch-chroot") != "$CHROOT_VERSION" ]]; then
	die "chroot '%s' is not at version %s. Please rebuild." "$working_dir" "$CHROOT_VERSION"
fi

build_mount_args
copy_hostconf

eval "$(grep '^CARCH=' "$working_dir/etc/makepkg.conf")"

[[ -z $nosetarch ]] || unset CARCH

exec ${CARCH:+setarch "$CARCH"} systemd-nspawn -q \
	-D "$working_dir" \
	-E "PATH=/usr/local/sbin:/usr/local/bin:/usr/bin" \
	--register=no --keep-unit --as-pid2 \
	"${mount_args[@]}" \
	"$@"