#!/bin/bash -euE
# librechroot

# Copyright 2010 Nicolás Reynolds
# Copyright 2011 Joshua Haase
# Copyright 2012-2013 Luke Shumaker
#
# This file is part of Parabola.
#
# Parabola 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, either version 3 of the License, or
# (at your option) any later version.
#
# Parabola 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.
#
# You should have received a copy of the GNU General Public License
# along with Parabola. If not, see <http://www.gnu.org/licenses/>.

# HACKING: if a command is added or removed, it must be changed in 3 places:
#   - the usage() text
#   - the commands=() array
#   - the case statement in main()

. $(librelib conf.sh)
load_files chroot

. libremessages
. $(librelib makechrootpkg)

# Because the makechrootpkg.sh library functions don't work with -euE
normshell() (
	set +euE
	"$@"
)

make_empty_repo() {
	local copydir=$1
	mkdir -p "${copydir}/repo"
	bsdtar -czf "${copydir}/repo/repo.db.tar.gz" -T /dev/null
	ln -s "repo.db.tar.gz" "${copydir}/repo/repo.db"
}

cmd=${0##*/}
usage() {
	calculate_directories
	echo "Usage: $cmd [OPTIONS] COMMAND [ARGS...]"
	echo 'Interacts with an archroot (arch chroot).'
	echo ''
	echo 'This is configured with `chroot.conf`, either in'
	echo '`/etc/libretools.d/`, or `$XDG_CONFIG_HOME/libretools/`.'
	echo 'The variables you may set are $CHROOTDIR, $CHROOT, and'
	echo '$CHROOTEXTRAPKG'.
	echo ''
	echo 'There may be multiple chroots; they are stored in $CHROOTDIR.'
	echo ''
	echo 'Each chroot is named; the default is configured with $CHROOT.'
	echo ''
	echo "Each named chroot has a master clean copy (named 'root'), and any"
	echo 'number of other named copies; the copy used by default is the'
	echo "current username (or \$SUDO_USER, or 'copy' if root)."
	echo ''
	echo 'The full path to the chroot copy is "$CHROOTDIR/$CHROOT/$COPY",'
	echo 'unless the copy name is manually specified as an absolute path,'
	echo 'in which case, that path is used.'
	echo ''
	echo 'The current settings for the above varibles are:'
	echo "    CHROOTDIR : ${CHROOTDIR:-ERROR: NO SETTING}"
	echo "    CHROOT    : ${CHROOT:-ERROR: NO SETTING}"
	echo "    COPY      : $COPY"
	echo "    rootdir   : ${rootdir:-ERROR}"
	echo "    copydir   : ${copydir:-ERROR}"
	echo ''
	echo 'If the chroot, or copy does not exist, it will be created'
	echo 'automatically.  A chroot by default contains the packages in the'
	echo 'group "base-devel", and any packages named in $CHROOTEXTRAPKG.'
	echo 'Unless the `-C` or `-M` flags are used, all configuration files'
	echo 'are the stock versions supplied in the packages, not the versions'
	echo 'from your host system.'
	echo ''
	echo 'This command will make the following configuration changes in'
	echo 'the chroot:'
	echo '  - overwrite `/etc/libretools.d/chroot.conf`'
	echo '  - overwrite `/etc/pacman.d/mirrorlist`'
	echo '  - set `CacheDir` in `/etc/pacman.conf`'
	echo 'If a new `pacman.conf` is inserted with the `-C` flag, the change'
	echo "is made after the file is copied in; the \`-C\` flag doesn't stop"
	echo 'the change from being effective.'
	echo ''
	echo 'Creating a copy, deleting a copy, or syncing a copy can be fairly'
	echo 'slow; but are very fast if $CHROOTDIR is on a btrfs partition.'
	echo ''
	echo 'Options:'
	echo '  -n <CHROOT>   Name of the chroot to use'
	echo '  -l <COPY>     Name of, or absolute path to, the copy to use'
	echo '  -N            Disable networking in the chroot'
	echo '  -C <file>     Copy this file to `$copydir/etc/pacman.conf`'
	echo '  -M <file>     Copy this file to `$copydir/etc/makepkg.conf`'
	echo ''
	echo 'Commands:'
	echo '  Create/copy/delete:'
	echo '    noop|make     Do not do anything, but still creates the'
	echo '                  chroot copy if it does not exist'
	echo "    sync          Sync the copy with the clean ('root') copy"
	echo "    delete        delete the chroot copy"
	echo '  Dealing with packages:'
	echo '    install-file FILES...       Like `pacman -U FILES...`'
	echo '    install-name NAMES...       Like `pacman -S NAMES...`'
	echo '    update        Like `pacman -Syu`'
	echo '    clean-pkgs    Remove all packages from the chroot copy that'
	echo '                  are not in base-devel, $CHROOTEXTRAPKG, or'
	echo '                  named as a dependency in the file'
	echo '                  `/build/PKGBUILD` in the chroot copy'
	echo '  Other:'
	echo '    run CMD...    Run CMD in the chroot copy'
	echo '    enter         Enter an interactive shell in the chroot copy'
	echo '    clean-repo    Clean /repo in the chroot copy'
	echo '    help          Show this message'
}
commands=(
	noop make sync delete
	install-file install-name update clean-pkgs
	run enter clean-repo help
)

# set $rootdir and $copydir; blank them on error
calculate_directories() {
	# Don't assume that CHROOTDIR or CHROOT are set,
	# but assume that COPY is set.

	if [[ -n ${CHROOTDIR:-} ]] && [[ -n ${CHROOT:-} ]]; then
		rootdir="${CHROOTDIR}/${CHROOT}/root"
	else
		rootdir=''
	fi

	if [[ ${COPY:0:1} = / ]]; then
		copydir=$COPY
	elif [[ -n ${CHROOTDIR:-} ]] && [[ -n ${CHROOT:-} ]]; then
		copydir="${CHROOTDIR}/${CHROOT}/${COPY}"
	else
		copydir=''
	fi
}

# Globals: $CHROOTDIR, $CHROOT, $COPY, $rootdir and $copydir
main() {
	COPY=$LIBREUSER
	[[ $COPY != root ]] || COPY=copy

	local mode=enter
	local archroot_args=()
	while getopts 'n:l:NC:M:' arg; do
		case $arg in
			n) CHROOT=$OPTARG;;
			l) COPY=$OPTARG;;
			N)
				# We do this so that it carries through to
				# chroot_* functions
				archroot() {
					$(which archroot) -N "$@"
				}
				;;
			C|M) archroot_args+=(-$arg "$OPTARG");;
			*) usage >/dev/stderr; return 1;;
		esac
	done
	shift $(($OPTIND - 1))
	if [[ $# -lt 1 ]]; then
		error "Must specify a command"
		usage >/dev/stderr
		return 1
	fi
	mode=$1
	if ! in_array "$mode" "${commands[@]}"; then
		error "Unrecognized command: \`$mode'"
		usage >/dev/stderr
		return 1
	fi
	shift

	if [[ $mode == help ]]; then
		usage
		return 0
	fi

	check_vars chroot CHROOTDIR CHROOT
	calculate_directories

	########################################################################

	if (( EUID )); then
		error "This program must be run as root."
		return 1
	fi

	umask 0022

	# Keep this lock as long as we are running
	# Note that '9' is the same FD number as in (mk)archroot
	lock_open_write 9 "$copydir" \
		"Waiting for existing lock on chroot copy to be released: [$COPY]"

	if [[ ! -d $rootdir ]]; then
		msg "Creating 'root' copy for chroot [$CHROOT]"
		set +u # if archroot_args is empty, it counts as unbound
		archroot "${archroot_args[@]}" -m "$rootdir" base-devel
		set -u
		make_empty_repo "$rootdir"
	fi

	if [[ ! -d $copydir ]] || [[ $mode == sync ]]; then
		msg "Syncing copy [$COPY] with root copy"
		normshell chroot_sync "$CHROOTDIR/$CHROOT" "$COPY"
	fi

	mkdir -p "$copydir/etc/libretools.d"
	{
		if [[ -n ${CHROOTEXTRAPKG[@]:-} ]]; then
			printf 'CHROOTEXTRAPKG=('
			printf "'%s' " "${CHROOTEXTRAPKG[@]}"
			printf ')\n'
		else
			printf 'CHROOTEXTRAPKG=()\n'
		fi
	} > "$copydir"/etc/libretools.d/chroot.conf

	if [[ $mode != delete ]]; then
		# "touch" the chroot first
		# this will
		#  - overwrite \`/etc/pacman.d/mirrorlist'"
		#  - set \`CacheDir' in \`/etc/pacman.conf'"
		#  - apply -C or -M flags
		set +u # if archroot_args is empty, it counts as unbound
		archroot "${archroot_args[@]}" -r "$copydir" true
		set -u
	fi

	########################################################################

	case "$mode" in
		# Creat/copy/delete
		noop|make|sync) :;;
		delete)
			if [[ -d $copydir ]]; then
				normshell chroot_delete "$copydir"
			fi
			;;

		# Dealing with packages
		install-file)
			normshell chroot_install_pkgs      "$copydir" "$@"
			normshell chroot_add_to_local_repo "$copydir" "$@"
			;;
		install-name) archroot -r "$copydir" pacman -Sy "$@";;
		update) archroot -u "$copydir";;
		clean-pkgs)
			trap "rm -f '$copydir'/clean '$copydir'/chrootexec" EXIT
			cp -a "$(which chcleanup)"  "$copydir/clean"
			echo '#!/bin/bash'        > "$copydir/chrootexec"
			echo 'mkdir /build'      >> "$copydir/chrootexec"
			echo 'cd /build; /clean' >> "$copydir/chrootexec"
			chmod 755 "$copydir/chrootexec"
			archroot -r "$copydir" /chrootexec
			;;

		# Other
		run)   archroot -r "$copydir" "$@";;
		enter) archroot -r "$copydir" bash;;
		clean-repo)
			rm -rf "${copydir}/repo/*"
			make_empty_repo "$copydir"
			;;
	esac
}

main "$@"