#!/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)

# umask might have been changed in /etc/profile
# ensure that sane default is set again
umask 0022

working_dir=''

files=()
mount_args=()

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="$OPTARG" ;;
		c) cache_dirs+=("$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.'

pacconf_cmd=$(command -v pacman-conf || command -v pacconf)

if (( ${#cache_dirs[@]} == 0 )); then
	mapfile -t cache_dirs < <($pacconf_cmd --config "${pac_conf:-$working_dir/etc/pacman.conf}" CacheDir)
fi

# shellcheck disable=2016
host_mirrors=($($pacconf_cmd --config "${pac_conf:-$working_dir/etc/pacman.conf}" --repo extra Server 2> /dev/null | sed -r 's#(.*/)extra/os/.*#\1$repo/os/$arch#;t;s#(.*/)[^/]+/extra(/?)$#\1$arch/$repo\2#'))

for host_mirror in "${host_mirrors[@]}"; do
	if [[ $host_mirror == *file://* ]]; then
		host_mirror=$(echo "$host_mirror" | sed -r 's#file://(/.*)/\$repo/os/\$arch#\1#g')
		for m in "$host_mirror"/pool/*/; do
			in_array "$m" "${cache_dirs[@]}" || cache_dirs+=("$m")
		done
	fi
done

while read -r line; do
	mapfile -t lines < <($pacconf_cmd --config "${pac_conf:-$working_dir/etc/pacman.conf}" \
		--repo $line Server | sed -r 's#(.*/)[^/]+/os/.+#\1#')
	for line in "${lines[@]}"; do
		if [[ $line = file://* ]]; then
			line=${line#file://}
			in_array "$line" "${cache_dirs[@]}" || cache_dirs+=("$line")
		fi
	done
done < <($pacconf_cmd --config "${pac_conf:-$working_dir/etc/pacman.conf}" --repo-list)

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

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

# {{{ functions
copy_hostconf () {
	unshare --fork --pid gpg --homedir "$working_dir"/etc/pacman.d/gnupg/ --no-permission-warning --quiet --batch --import --import-options import-local-sigs "$(pacman-conf GpgDir)"/pubring.gpg >/dev/null 2>&1
	pacman-key --gpgdir "$working_dir"/etc/pacman.d/gnupg/ --import-trustdb "$(pacman-conf GpgDir)" >/dev/null 2>&1

	printf 'Server = %s\n' "${host_mirrors[@]}" | \
		tee "$working_dir/etc/pacman.d/mirrorlist" > \
		"$working_dir/etc/pacman.d/mirrorlist32"

	[[ -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 = ${cache_dirs[*]}|g" -i "$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

copy_hostconf

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

[[ -z $nosetarch ]] || unset CARCH
if [[ -f "@pkgdatadir@/setarch-aliases.d/${CARCH}" ]]; then
	read -r set_arch < "@pkgdatadir@/setarch-aliases.d/${CARCH}"
else
	set_arch="${CARCH}"
fi

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