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

export PREFIX=@TERMUX_PREFIX@

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

show_usage() {
	msg
	msg "Usage: termux-backup [output file]"
	msg
	msg "Script for backing up Termux installation directory, \$PREFIX."
	msg "It WILL NOT backup your home directory."
	msg
	msg "Backup is performed as TAR archive. Compression is determined"
	msg "by output file extension. If file name is '-', then tarball is"
	msg "written to stdout and is uncompressed."
	msg
}

if [ $# -lt 1 ]; then
	msg
	msg "[!] Output 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

if [ ! -d "$PREFIX" ]; then
	msg "[!] $PREFIX: directory does not exist."
	exit 1
fi

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

if [ "$BACKUP_FILE_PATH" != "-" ]; then
	CAN_AUTOCOMPRESS=yes
	if [ -e "$BACKUP_FILE_PATH" ]; then
		msg
		msg "[!] Refusing to overwrite already existing file '$BACKUP_FILE_PATH'."
		msg
		exit 1
	fi
else
	CAN_AUTOCOMPRESS=
fi

tar --warning=no-file-ignored -f "$BACKUP_FILE_PATH" \
	-c ${CAN_AUTOCOMPRESS+--auto-compress} \
	-C "@TERMUX_BASE_DIR@" ./usr