#!/bin/bash

MAILID=$1
[ -z "$MAILID" ] && echo "Usage : $0 [mailid]" && exit 1

DEBUG=0
[ "$2" == "-d" ] && DEBUG=1

MAX_LOG=9

HOSTNAME=$( hostname -f )

function search_user () {
	MAILID=$1
	MAILLOG=$2
	[ ! -f "$MAILLOG" ] && MAILLOG=$MAILLOG.gz
	[ -f "$MAILLOG" ] && zgrep $MAILID $MAILLOG|grep 'sasl_username='|sed 's/^.*sasl_username=//'
}

function search_user_from_mailid() {
	MAILID=$1
	[ $DEBUG -eq 1 ] && echo "Search username from Mail ID $MAILID ..."
	res=$( search_user $MAILID /var/log/mail.log )
	if [ -n "$res" ]
	then
		echo "$res"
		exit 0
	else
		[ $DEBUG -eq 1 ] && echo "Not found from log file /var/log/mail.log. Try with archive (Max : $MAX_LOG)"
		for i in $( seq 1 $MAX_LOG )
		do
			res=$( search_user $MAILID /var/log/mail.log.$i )
			if [ -n "$res" ]
			then
				echo "$res"
				exit 0
			else
				[ $DEBUG -eq 1 ] && echo "Not found from log file /var/log/mail.log.$i"
			fi
		done
		[ $DEBUG -eq 1 ] && echo "Not found in archive (Max : $MAX_LOG)"
	fi
}

if [ $( mailq|egrep -c ^$MAILID ) -ne 0 ]
then
	[ $DEBUG -eq 1 ] && echo "Mail $MAILID still in mailq. Try to detect original mail ID ..."
	ORIGMAILID=$( postcat -q "$MAILID" |grep "by $HOSTNAME"|tail -n 1|sed 's/^.*by .* with.* id \([A-Z0-9]*\).*$/\1/' )
	if [ -n "$ORIGMAILID" ]
	then
		if [ "$ORIGMAILID" != "$MAILID" ]
		then
			[ $DEBUG -eq 1 ] && echo "Original mail ID : $ORIGMAILID"
			search_user_from_mailid "$ORIGMAILID"
			[ $DEBUG -eq 1 ] && echo "User not found from original mail ID"
			exit 1
		else
			[ $DEBUG -eq 1 ] && echo "Mail ID and original mail ID are equals"
		fi
	else
		[ $DEBUG -eq 1 ] && echo "Fail to detect original mail ID. Continue with mail ID in parameter"
	fi
fi

search_user_from_mailid "$MAILID"
[ -n "$ORIGMAILID" ] && echo "User not found" && exit 1

[ $DEBUG -eq 1 ] && echo "User not found. Try to detect original mail ID with message ID in log"

MSGID=$( mailid_to_messageid "$MAILID" )

if [ -z "$MSGID" ]
then
	[ $DEBUG -eq 1 ] && echo "Message ID not found from log."
	exit 1
fi

[ $DEBUG -eq 1 ] && echo "Message ID found : $MSGID. Try to detect original mail ID with this message ID"

ORIGMAILID=$( messageid_to_original_mailid "$MSGID" )

if [ -z "$ORIGMAILID" ]
then
	[ $DEBUG -eq 1 ] && echo "Original mail ID not found from message ID"
	exit 1
fi

search_user_from_mailid "$ORIGMAILID"
[ $DEBUG -eq 1 ] && echo "Username not found from original mail ID"

exit 1