#!/bin/bash
# Copyright (c) 2010 Switzernet by Emin Gabrielyan and Oussama Hammami

# CleanIMAPunsync v100604.2
# This script is a complementary to imapsync
# It deletes the folders that exist in the destination server
# but do not exist in the source. The imapsync does not delete 
# folders in the destination server that are not in the source
# If you periodically sync with cron, and frequently rename folders
# on the source server, imapsync would copy each renamed instance
# to the destination and you may endup with multiple copies of the
# same folder on the destination server. This script solves this problem.
# You must run this script periodically, before or after the imapsync.
#
#

ver=100604.a26.sh
prog=cleanimapunsync

workroot=/var/tmp
log=/var/log/$prog.log

function usage
{
  echo
  echo "Celans the IMAP folders on the destination backup server,"
  echo "not existing anymore in the source IMAP server."
  echo
  echo Usage:
  echo
  echo " host1=mail2.switzernet.com user1=support@mail2.switzernet.com pass1=xxxx dir1=\"INBOX/Support/4 Reception/\" \\"
  echo " host2=backup.switzernet.com user2=admin@backup.switzernet.com pass2=yyyy dir2=\"support.INBOX.Support.4 Reception.\" $prog"
  echo
  exit
}

if [ -z "$host1" -o -z "$host2" ]
then
  echo "Error: one or both hosts are unknown"
  usage
fi

if [ -z "$user1" -o -z "$user2" ]
then
  echo "Error: one or both usernames are unknown"
  usage
fi

if [ -z "$pass1" -o -z "$pass2" ]
then
  echo "Error: one or both passwords are unknown"
  usage
fi

if [ -z "$dir1" -o -z "$dir2" ]
then
  echo "Error: one or both root directories are unknown"
  usage
fi


#echo "host1=$host1"
#echo "user1=$user1"
#echo "pass1=$pass1"
#echo "dir1=$dir1"
#echo "host2=$host2"
#echo "user2=$user2"
#echo "pass2=$pass2"
#echo "dir2=$dir2"

out1=a,out1.txt
folders1=b,folders1.txt
list1=c,list1.txt

out2=a,out2.txt
folders2=b,folders2.txt
list2=c,list2.txt

intersect=d,intersect.txt
zombies=e,zombies.txt
deleted=f,deleted.txt

time=`date +%Y%m%d,%H%M%S`
work=${workroot}/$time,$prog,$ver,$$,$RANDOM

cd $workroot

if [ $? -ne 0 ]
then
  echo Error: cannot go into work root $workroot
  exit
fi

mkdir $work

if [ $? -ne 0 ]
then
  echo Error: cannot create work dir $work
  exit
fi

cd $work

if [ $? -ne 0 ]
then
  echo Error: cannot move into work $work
  exit
fi

function imap_list
{

  tag=2000

  (sleep 0.5; echo "1000 login $user $pass"; sleep 0.5; echo "$tag list \"$dir\" *"; sleep 0.5; echo "3000 logout"; sleep 1.5) | telnet $host imap > $out 2>&1

  if [ ! -f $out ]
  then
    echo "`date +%Y-%m-%d\ %H:%M:%S` Error: connection problem, output file $out is not found" >> $log
    exit
  fi

  if grep -qi "^$tag OK LIST completed" $out
  then
    echo ok > /dev/null
  else
    echo "`date +%Y-%m-%d\ %H:%M:%S` Error: connection problem with $user@$host, IMAP list is not obtained or incomplete" >> $log
    exit
  fi

  cat $out | perl -ne 'if(/^\* +LIST +\([^)]*\) +\"[^"]+\" \"([^"]+)\"/){$s=$1; print $s."\n"}' > $folders

  cat $folders | perl -e '$d="'"$dir"'"; $d=~s/\//\\\//g; while(<>){s/^$d//; s/\//./g; s/[,;]/'\''/g; print}' > $list

}

host=$host1 user=$user1 pass=$pass1 dir=$dir1 out=$out1 folders=$folders1 list=$list1 imap_list
host=$host2 user=$user2 pass=$pass2 dir=$dir2 out=$out2 folders=$folders2 list=$list2 imap_list

cat $list1 $list2 | sort | uniq -c | perl -ne 'print $1."\n" if(/^ *2 +(.*)$/)' > $intersect
cat $intersect $list2 | sort | uniq -c | perl -ne 'print $1."\n" if(/^ *1 +(.*)$/)' > $zombies

(
  sleep 0.5
  echo "1000 login $user2 $pass2"
  i=1
  cat $zombies | perl -ne 's/^/</; s/$/>/; print' | while read s
  #The middle pipe adding <> protects fro read's trim
  do
    sleep 0.5
    #The next version of line is without regex side effects as perl eq is used for comparison
    line=`(echo "$s"; cat $list2) | perl -ne '$i++ if($s); s/[\n\r]//g; $s=$_ if(! $i); if("<$_>" eq $s) {print $i; last}'`
    rm="`head -$line $folders2 | tail -1`"
    imap="$((2000+i)) delete \"$rm\""
    echo `date +%Y-%m-%d\ %H:%M:%S` IMAP: $imap >> $log 
    echo $imap
    i=$((i+1))
  done
  sleep 0.5
  echo 3000 logout
  sleep 1.5
) | telnet $host2 imap > $deleted 2>&1

n=`wc -l $zombies | cut -d\  -f1`

err=0
for((i=1;i<=n;i++))
do
  grep -iq "^$((2000+i)) OK Delete completed" $deleted || err=$((err+1))
done

if [ $err -gt 0 ]
then
  echo "`date +%Y-%m-%d\ %H:%M:%S` Error: $err out of $n folders seems are not deleted" >> $log
else
  echo "`date +%Y-%m-%d\ %H:%M:%S` OK: $n folders are deleted" >> $log
fi


rm $out1
rm $folders1
rm $list1

rm $out2
rm $folders2
rm $list2

rm $intersect
rm $zombies
rm $deleted

cd ..
rmdir $work