#!/usr/bin/perl

# MC extfs for (possibly compressed) Berkeley style mailbox files
# Peter Daum <gator@cs.tu-berlin.de> (Jan 1998, mc-4.1.24)

$zcat="zcat";                 # gunzip to stdout
$bzcat="bzip2 -dc";           # bunzip2 to stdout
$file="file";                 # "file" command
$TZ='GMT';                    # default timezone (for Date module)

if (eval "require Date::Parse") { # fancy date parsing available?
    import Date::Parse;
    $parse_date= 
	sub {
	    local $_ =localtime(str2time($_[0],$TZ));
	    s/^... (.+) (\d\d:\d\d):\d\d (\d\d\d\d)$/$1 $3 $2/;
	    return $_;
	}
} else {			# use "light" version
    $parse_date= sub {
	# assumes something like: Mon, 5 Jan 1998 16:08:19 +0200 (GMT+0200)
	# if you have mails with another date format, add it here
	if (/(\d\d?) ([A-Z][a-z][a-z]) (\d\d\d\d) (\d\d?:\d\d)/) {
	    return "$2 $1 $3 $4";
	}
	# Y2K bug.
	# Date: Mon, 27 Mar 100 16:30:47 +0000 (GMT)
	if (/(\d\d?) ([A-Z][a-z][a-z]) (1?\d\d) (\d\d?:\d\d)/) {
	    $correct_year = 1900 + $3;
	    if ($correct_year < 1970) {
		$correct_year += 100;
	    }
	    return "$2 $1 $correct_year $4";
	}
	# AOLMail(SM).
	# Date: Sat Jul 01 10:06:06 2000
	if (/([A-Z][a-z][a-z]) (\d\d?) (\d\d?:\d\d)(:\d\d)? (\d\d\d\d)/) {
	    return "$1 $2 $5 $3";
	}
	# Fallback
	return "Jan 1 1980 00:00";
    }
}

sub process_header {
    while (<IN>) {
	s/\r$//;
	last if /^$/;
	die "unexpected EOF\n" if eof;
	if (/^Date:\s(.*)$/) {
	    $date=&$parse_date($1);
	} elsif (/^Subject:\s(.*)$/) {
	    $subj=$1;
	    $subj=~ s/^(re:\s?)+//gi;  # no leading Re:
	    $subj=~ tr/a-zA-Z0-9//cd; # strip all "special" characters
	} elsif (/^From:\s.*?(\w+)\@/) {
	    $from=$1;
	} elsif (/^To:\s.*?(\w+)\@/) {
	    $to=$1;
	}
    }
}

sub print_dir_line {
    $from=$to if ($from eq $user); # otherwise, it would look pretty boring
    printf "-r-------- 1 $< $< %d %s %3.3d_%.16s\n", 
    $line, $date, $msg_nr, "${from}_${subj}";
}

sub mailfs_list {
    my $blank = 1;
    $user=$ENV{USER}||getlogin||getpwuid($<) || "nobody";
    
    while(1) {
	$_=<IN>;
	s/\r$//;
	if (!defined($_)) {	# EOF
	    print_dir_line; 
	    exit 0;
	}
	if($blank && /^From /) { # Start of header
	    print_dir_line unless (!$msg_nr);
	    $msg_nr++;
	    ($from,$to,$subj,$date)=("none","none","none", "01-01-80");
	    process_header;
	    $line=$blank= 0;
	} else {
	    $line++;
	    $blank= /^$/;
	}
    }
}

sub mailfs_copyout {
    my($source,$dest)=@_;
    exit 1 unless (open STDOUT, ">$dest");
    ($nr)= ($source =~ /^(\d+)/); # extract message number from "filename"
    
    my $blank = 1;
    while(<IN>) {
	s/\r$//;
	if($blank && /^From /) {
	    $msg_nr++;
	    exit(0) if ($msg_nr > $nr);
	    $blank= 0;
	} else {
	    $blank= /^$/;
	}
	print if ($msg_nr == $nr);
    }
}

# main {
$msg_nr=0;
$cmd=shift;
$mbox_name=shift;
$_=`$file $mbox_name`;

if (/gzip/) {
    exit 1 unless (open IN, "$zcat $mbox_name|");
} elsif (/bzip/) {
    exit 1 unless (open IN, "$bzcat $mbox_name|");
} else {
    exit 1 unless (open IN, "<$mbox_name");
}

umask 077;

if($cmd eq "list") { &mailfs_list; exit 0; }
elsif($cmd eq "copyout") { &mailfs_copyout(@ARGV); exit 0; }

exit 1;