#! /bin/bash
# Usage: aes.sh (enc|dec) filename
#	enc filename will encrypt the file, saving it to filename.aes
#	dec filename will decrypt the file, striping the .aes from the filename, or just the filename.

ACTION=$1
FILENAME=$2

if [ "$ACTION" = "enc" -o "$ACTION" = "dec" ]; then
	if [ "$ACTION" = "enc" -a -e "$FILENAME" ]; then
		openssl enc -in "$FILENAME" -out "$FILENAME.aes" -e -aes256 #Encrypt the file.
	elif [ "$ACTION" = "dec" -a -e "$FILENAME" ]; then
		openssl enc -in "$FILENAME" -out "${FILENAME%.*}" -d -aes256 #Decrypt the file.
	elif [ ! -e "$FILENAME" ]; then
		echo -e "Usage: `basename "$0"` (enc|dec) filename"
		echo -e "\tThe file, \"$FILENAME\", does not exist."
	else
		echo -e "Usage: `basename "$0"` (enc|dec) filename"
		echo -e "\tYou need to specify to encrypt(enc) or decrypt(dec)."
	fi
else
	if [ -z "$ACTION" -a -z "$FILENAME" ]; then
		echo -e "Usage: `basename "$0"` (enc|dec) filename"
		echo -e "\t(enc|dec): 'enc' encrypts filename."
		echo -e "\t           'dec' decrypts filename."
		echo -e "\tfilename: path of file to perform operation on."
	elif [ "$ACTION" != "enc" -a "$ACTION" != "dec" ]; then
		echo -e "Usage: `basename "$0"` (enc|dec) filename"
		echo -e "\tYou need to specify to encrypt(enc) or decrypt(dec)."
	elif [ -n "$ACTION" -a -z "$FILENAME" ]; then 
		echo -e "Usage: `basename "$0"` (enc|dec) filename"
		echo -e "\tYou must supply a file to process."
	elif [ ! -e "$FILENAME" ]; then
		echo -e "Usage: `basename "$0"` (enc|dec) filename"
		echo -e "\tThe file, \"$FILENAME\", does not exist."
	else
		echo -e "Unknown error: you should never see me!"
		echo -e "\t\$1(Action): $ACTION"
		echo -e "\t\$2(Filename): $FILENAME"
	fi
fi

exit 0