#! /bin/sh

BIN="cryptot"
CIPHER="-c 2"

usage () {
	echo "usage : `basename $0` -(e|d) input_file password [output_file]"
	echo "        -e  : encryption."
	echo "        -d  : decryption."
	echo "              if output_file is omited, output is written to stdout."
}

work () {
	if [ "$1" == "-e" ];then
		echo "encrypt         : $2"
		MODE=""
	else
		echo "decrypt         : $2"
		MODE="-x"
	fi
	echo "use password    : $3"
	if [ $# -eq 4 ]; then
		echo "write output to : $4"
	else
		echo "write output to : stdout"
	fi
	echo "hit Enter to proceed.  type Ctrl-C to abort."
	read -t 5 A
	if [ $? -ne 0 ]; then echo "=> timeout ... operation aborted." && exit; fi
	CMD="${BIN} ${MODE} ${CIPHER} $3"	
	if [ $# -eq 4 ]; then
		cat $2 | ${CMD} > $4
	else
		cat $2 | ${CMD}
	fi
	if [ "$1" == "-e" ];then
		echo "hit Enter to remove $2.  type Ctrl-C to abort."
		read -t 4 A
		if [ $? -ne 0 ]; then echo "=> timeout ... nothing done." && exit; fi
		rm $2 $2~ 2>/dev/null
	fi
}


if [ $# -lt 3 -o $# -gt 4 ]; then usage && exit; fi
if [ ! -f $2 ];then
	echo "$2 isn't a regular file"
	exit
fi
case "$1" in
	"-e"|"-d")
	work $@
	;;
	*)
	echo $CHOICE
	usage;;
esac