#!/bin/bash
#
# Script to add/delete users or change their passwords for
# Dovecot/Postfix using Virtual Users

USAGE="Usage: $0 OPTION EMAIL [BASEDIR]\n\nOptions:\n\t-a: add user\n\t-d: delete user\n\t-c: change password"

if [ ! -n "$2" ]
then
	echo -e $USAGE
	exit 1
fi

USERNAME=$(echo "$2" | cut -f1 -d@);
DOMAIN=$(echo "$2" | cut -f2 -d@);
MAIL_REGEX="^[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,4}$"

if [[ ! "$2" =~ $MAIL_REGEX ]]; then
	echo "ERROR: Invalid email address."
	exit 2
fi
ADDRESS=$2

if [ -n "$3" ]
then
	if [ ! -d "$3" ]; then
		echo -e $USAGE
		echo "ERROR: BASEDIR must be a valid directory!"
		echo "I would have tried $(postconf | grep ^virtual_mailbox_base | cut -f3 -d' ')"
		exit 2
	else
		BASEDIR="$3"
	fi
else
	BASEDIR="$(postconf | grep ^virtual_mailbox_base | cut -f3 -d' ')"
fi

VMAILBOX="/etc/postfix/vmailbox"
PASSWD="$BASEDIR/$DOMAIN/passwd"
SHADOW="$BASEDIR/$DOMAIN/shadow"

[ -d "$BASEDIR/$DOMAIN" ] || (mkdir "$BASEDIR/$DOMAIN" && chown vmail:vmail "$BASEDIR/$DOMAIN")
[ -f "$VMAILBOX" ] || (touch $VMAILBOX && echo "Warning: $VMAILBOX not existent. Creating it.")

case $(echo $1 | cut -f2 -d-) in
	# Add user
	'a')
		grep_ret=1
		paths=("$PASSWD" "$SHADOW")
		for p in $paths; do
			grep "$USERNAME:" $p > /dev/null 2>&1
			grep_ret=$(($grep_ret && $?))
		done
		grep "$ADDRESS" $VMAILBOX > /dev/null 2>&1
		if [ 1 -ne $(($grep_ret && $?)) ]; then
			echo "ERROR: User $ADDRESS already exists."
			exit 3
		fi
		if [ -f $VMAILBOX ]
		then	    
			echo "Adding Postfix user configuration..."	   	    
			echo $ADDRESS $DOMAIN/$USERNAME/ >> $VMAILBOX
			postmap $VMAILBOX

			if [ $? -eq 0 ]
			then			       
				echo "Adding Dovecot user configuration..."
				echo $USERNAME::5000:5000::$BASEDIR/$DOMAIN/$USERNAME >> $PASSWD
				echo $USERNAME":"$(doveadm pw -s SHA512-CRYPT) >> $SHADOW
				chown vmail:vmail $PASSWD && chmod 600 $PASSWD
				chown vmail:vmail $SHADOW && chmod 600 $SHADOW
				/etc/init.d/postfix reload
			fi

		fi
		;;

	# Delete user
	'd')	
		echo "Deleting user $ADDRESS. Remove user's mail directory? [y/n]: "
		sed -i "/$ADDRESS.*/d" $VMAILBOX
		postmap $VMAILBOX
		sed -i "/$USERNAME.*/d" $PASSWD
		sed -i "/$USERNAME.*/d" $SHADOW
		rm -rI "$BASEDIR/$DOMAIN/$USERNAME" > /dev/null 2>&1
		if [ ! -s $SHADOW ] && [ ! -s $PASSWD ] && [ $(find $BASEDIR/$DOMAIN -maxdepth 0 -type d 2>/dev/null) ]; then
			echo "Remove empty directory $BASEDIR/$DOMAIN? [y/n]: "
			rm -rI "$BASEDIR/$DOMAIN" > /dev/null 2>&1
		fi
		/etc/init.d/postfix reload
		;;

	# Change user's password
	'c')
		echo "Changing password for $ADDRESS"
		sed -i "s#$USERNAME:.*#$USERNAME:$(doveadm pw -s SHA512-CRYPT)#" $SHADOW
		;;

	*)
		echo -e $USAGE
		;;

esac

exit 0