#!@TERMUX_PREFIX@/bin/bash
set -e -u

export PREFIX=@TERMUX_PREFIX@

msg() {
	echo "$*" >&2
}

show_usage() {
	msg
	msg "Usage: termux-restore [input file]"
	msg
	msg "Script for restoring Termux installation directory (\$PREFIX)"
	msg "from the given TAR archive."
	msg
	msg "It is expected that backup file was made by 'termux-backup'."
	msg "Restoring procedure will erase all files in \$PREFIX directory"
	msg "that are not present in the given backup file. Be careful."
	msg
	msg "Backup contents may be supplied via stdin by specifying input"
	msg "file as '-'. Note that piped TAR archive must be uncompressed."
	msg
}

if [ $# -lt 1 ]; then
	msg
	msg "[!] Input file path is not specified."
	show_usage
	exit 1
fi

if [ $# -gt 1 ]; then
	shift 1
	msg
	msg "[!] Got extra arguments: $*"
	show_usage
	exit 1
fi

case "$1" in
	-\?|-h|--help|--usage) show_usage; exit 0;;
	*) BACKUP_FILE_PATH=$1;;
esac

if [ "$BACKUP_FILE_PATH" != "-" ] && [ ! -e "$BACKUP_FILE_PATH" ]; then
	msg
	msg "[!] File '$BACKUP_FILE_PATH' does not exist."
	msg
	exit 1
else
	if [ "$BACKUP_FILE_PATH" != "-" ] && [ ! -f "$BACKUP_FILE_PATH" ]; then
		msg
		msg "[!] Path '$BACKUP_FILE_PATH' is not a regular file."
		msg
		exit 1
	fi
fi

# Ensure that prefix doesn't contain read-only files.
find "@TERMUX_PREFIX@" -type d -print0 | xargs -0 -r chmod u+rwx
find "@TERMUX_PREFIX@" -type f -print0 | xargs -0 -r chmod u+rw

# --recursive-unlink is added intentionally to delete all orphan/extra files
# in $PREFIX. It must be restored to a clean state as in backup tarball.
tar -x -C "@TERMUX_BASE_DIR@" -f "$BACKUP_FILE_PATH" \
	--recursive-unlink --preserve-permissions ./usr