#!/usr/bin/perl -w

######################################################################
#
# cyrus2dovecot
#
# V E R S I O N :
# 0.1
#
# A U T H O R :
# Jan Trukenmüller
# http://trukenmueller.de
#
# L O C A T I O N :
# http://trukenmueller.de/cyrus2dovecot
#
# W H A T :
# This script converts a CYRUS mail directory into a DOVECOT mail
# directory.
# Perhaps the resulting mail directory can also be used with other
# allpications using the 'Maildir' format, but I only tested it with
# Dovecot.
#
# F E A T U R E S :
# - The conversion works even if the cyrus server is offline - e.g.
#   because it is broken and cannot be started any more. The cyrus
#   databases may also be broken, because they are not needed. Only
#   the mail directory and it's plaintext mail files are used for
#   the conversion.
# - The complete mail directory and all subdirectories are converted
#   in a single run.
#
# B U G S :
# - All the converted Mails are marked as unread.
# - Only one Mail account can be converted at a time
# - probably a lot more...
#
# R E Q U R E M E N T S :
# This script runs on a Gentoo Linux system with Cyrus 2.2.12 and
# Dovecot 1.0_rc29. It should also run on other UNIX-like systems.
# A Perl interpreter is also required.
#
# I N S T A L L A T I O N :
# Copy the script to a good looking place inside your file system,
# e.g. /usr/local/bin. Than make it executable.
#
# U S A G E :
# cyrus2dovecot <src-dir> <target-dir>
#     <src-dir> is the directory of your cyrus mailbox,
#     <target-dir> is the directory of dovecot
# E X A M P L E :
# cyrus2dovecot /var/spool/imap/j/user/joe /home/joe/Maildir
#
# O W N   R I S K :
# You can use this script at your own risk. The author does not take
# the responsibility for any damage the script may cause directly or
# indirectly.
#
# L I C E N C E :
# Well, there is no licence.
# Anyone may freely use, modify and redistribute this script.
# However, if you make any changes I would appreciate if you inform
# me about what you changed and why you did it.
#
# W H Y :
# The Cyrus server I used is broken and does not start any more. This
# was the right time for me to switch to another IMAP server. I
# decided to use Dovecot.
# In order to convert my mails I tried out two programs:
# cyrus2courier (http://www.madness.at/projects/#c2c) and
# cyrus2maildir.py (http://www.majid.info/mylos/weblog/2006/03/08-1.html)
# Both did not work for me. Perhaps they need the Cyrus IMAP server
# working, or at least a consistend Cyrus database - I don't know,
# because I didn't look so deep into the code.
# So I wrote this conversion script to be independent from a working
# Cyrus server.
#
# This script was the work of one evening. Time to go to bed now.
#
######################################################################

use strict;

my $src = shift || "";
my $target = shift || "";

usage('') unless( $src && $target );
usage("Source directory does not exist: $src") unless( -e $src );
system "mkdir '" . $target . "'" unless -e $target;
usage("Cannot create target directory: $target") unless( -e $target );
system "mkdir '" . "$target/cur" . "'" unless -e "$target/cur";
system "mkdir '" . "$target/new" . "'" unless -e "$target/new";
system "mkdir '" . "$target/tmp" . "'" unless -e "$target/tmp";

convert_dir( $src, $target, '.INBOX', '' );

sub usage{
	my $msg = shift;
	if($msg){
		print "\nERROR: $msg\n\n";
	}
	print "\tusage:
	\t$0 <Source-Directory> <Target-Directory>
	example:
	\t$0 /var/spool/imap/j/user/joe /home/joe/Maildir\n\n";
	exit 1;
}

sub convert_dir{
	my $s = shift;		# source directory
	my $t = shift;		# root of the target directory
	my $sub = shift;	# subdirectory under $t
	my $dh = shift;		# directory handle
	$dh .= 'x';
	no strict 'refs';
	opendir $dh, $s or die "Can't open $s for reading: $!\n";
	while (my $file = readdir $dh){
		next if $file =~ /^\.{1,2}$/; # ignore '.' and '..'
		if( -d "$s/$file" ){
			# It's a directory.
			system "mkdir '" . "$t/$sub.$file" . "'" unless -e "$t/$sub.$file";
			usage("Cannot create target directory: $t/$sub.$file") unless( -e "$t/$sub.$file" );
			system "mkdir '" . "$t/$sub.$file/cur" . "'" unless -e "$t/$sub.$file/cur";
			system "mkdir '" . "$t/$sub.$file/new" . "'" unless -e "$t/$sub.$file/new";
			system "mkdir '" . "$t/$sub.$file/tmp" . "'" unless -e "$t/$sub.$file/tmp";
			system "echo '" . substr( $sub, 1 ) . ".$file' >> $t/subscriptions";
			# recursion
			convert_dir("$s/$file", $t, "$sub.$file", $dh);
		}else{
			# It's a normal file.
			next if $file =~ /^cyrus\.(cache|header|index)$/; # ignore cyrus' binary files
			if( $sub eq '.INBOX' ){
				system "cp '$s/$file' '$t/cur'";
			}else{
				system "cp '$s/$file' '$t/$sub/cur'";
			}
		}
	}
	closedir $dh;
}