#!/usr/bin/perl
use warnings;
use strict;
use File::Copy;
use File::Slurp;
chdir or die "cannot chdir to home directory: $!";

# Just hope there are no magic chars in these filenames.
my $todo = 'mail/new_mail';
my $todo_filtered = 'mail/new_mail_not_obvious_spam';
my $tagged = 'mail/new_mail_tagged';
#my $notspam = 'mail/new_mail_notspam';
#my $spam = 'mail/new_mail_spam';
my $inbox = 'mail/inbox';
#my $inbox_spam = 'mail/inbox_spam';
my $delivery = '.email';
my $spam_to_learn = 'mail/spam';
my $spam_learned = 'mail/spam_learned';
my $ham_to_learn = 'mail/ham';
my $ham_learned = 'mail/ham_learned';

START:
foreach ($todo, $tagged) { die "$_ already exists" if -e }

sub append( $$ ) {
    my ($from, $to) = @_;
    my $got = read_file $from;
    local *APPEND;
    open APPEND, '>>', $to
      or die "cannot open $to for appending: $!";
    print APPEND $got or die "cannot write to $to: $!";
    close APPEND or die "cannot close $to: $!";
}

if (0) {
my $sa_update = 'sa-update';
print "running $sa_update\n";
if (system($sa_update)) {
    # Copied from perlfunc(1).  Is there a CPAN module to do this?
    if ($? == -1) {
	die "failed to run $sa_update: $!\n";
    }
    elsif ($? & 127) {
	die(sprintf("$sa_update died with signal %d, %s coredump\n",
		    ($? & 127), ($? & 128) ? 'with' : 'without'));
    }
    else {
	my $exit_status = $? >> 8;
	if ($exit_status == 1) {
	    print "no updates\n";
	}
	else {
	    die "$sa_update failed with exit status $exit_status\n";
	}
    }
}
else {
    print "downloaded updates ok\n";
}
}

my @learn = ([ $spam_to_learn, '--report', $spam_learned ],
	     [ $ham_to_learn, '--revoke', $ham_learned ]);
foreach (@learn) {
    my ($in, $flag, $out) = @$_;
    next if not -e $in;
    print "learning from $in\n";
    system('spamassassin', '--progress', $flag, '--mbox', $in)
      && die "spamassassin $flag failed";
    print "done $in, appending it to $out\n";
    append $in, $out;
    print "unlinking $in\n";
    unlink $in or die "cannot unlink $in: $!";
}

if (not -e $delivery) {
    print "$delivery not there, no new mail to process\n";
    exit;
}

print "moving $delivery to $todo\n";
move $delivery, $todo or die "cannot move $delivery to $todo: $!";

my $grepmail_not_spam = "grepmail -vh 'X-Spam-Status: Yes'";
my $grepmail_spam = "grepmail -h 'X-Spam-Status: Yes'";
print "filtering out messages in $todo already marked as spam and writing to $todo_filtered\n";
system("$grepmail_not_spam $todo >$todo_filtered")
  && die 'grepmail failed';
print "spam-checking $todo_filtered and writing to $tagged\n";
system("spamassassin --progress --mbox $todo_filtered >$tagged")
  && die 'spamassassin failed';
#print "filtering non-spam messages from $tagged to $notspam\n";
#system("$grepmail_not_spam $tagged >$notspam")
#  && die 'grepmail failed';
#print "filtering spam messages from $tagged to $spam\n";
#system("$grepmail_spam $tagged >$spam")
#  && die 'grepmail failed';
#die 'size mismatch' if (-s $notspam) + (-s $spam) != -s $tagged;
#print "appending $notspam to $inbox\n";
#append $notspam, $inbox;
#print "appending $spam to $inbox_spam\n";
#append $spam, $inbox_spam;
#my @to_unlink = ($todo, $todo_filtered, $tagged, $notspam, $spam);

print "appending $tagged to $inbox\n";
append $tagged, $inbox;
my @to_unlink = ($todo, $todo_filtered, $tagged);

print "unlinking @to_unlink\n";
unlink @to_unlink or die "cannot unlink @to_unlink: $!";

goto START;