# Movable Type (r) Open Source (C) 2006-2010 Six Apart, Ltd.
# This program is distributed under the terms of the
# GNU General Public License, version 2.
#
# $Id: spamlookup.pm 5151 2010-01-06 07:51:27Z takayama $

# Original copyright (c) 2004-2006, Brad Choate and Tobias Hoellrich

package spamlookup;

use strict;
use MT::JunkFilter qw(ABSTAIN);

sub tborigin {
    my $plugin = shift;
    my ($obj) = @_;

    # only filter TrackBack pings...
    return (ABSTAIN) unless UNIVERSAL::isa($obj, 'MT::TBPing');

    my $domain = extract_domains($obj->source_url, 1);

    my $config = $plugin->get_config_hash('blog:' . $obj->blog_id); # config($plugin);
    my $pingip = $obj->ip;

    if (domain_or_ip_in_whitelist($domain, $pingip, $config->{whitelist})) {
        return (ABSTAIN);
    }

    my $score = int($config->{tborigin_weight}) || 1;
    my $domainip = checkdns($domain);
    if (!$domainip) {
        return (-1 * $score, MT->translate("Failed to resolve IP address for source URL [_1]", $obj->source_url));
    }

    my @domainip = split /\./, $domainip;
    my @pingip = split /\./, $pingip;
    
    my $distance = 4;
    foreach (0..3) {
        if ($domainip[$_] == $pingip[$_]) {
            $distance--; 
        } else {
            last;
        }
    }

    return (ABSTAIN) if $distance < 3;

    # reverse lookup ip address if we can. if it matches to the
    # domain of the source url, then ABSTAIN.

    my $hostname = reversedns($pingip);
    if ($hostname) {
        if (domain_or_ip_in_whitelist($hostname, undef, $config->{whitelist})) {
            return (ABSTAIN);
        }
        $domain = lc $domain;
        $hostname = lc $hostname;
        if ($domain =~ m/\Q$hostname\E$/) {
            return (ABSTAIN);
        }
    }

    # check distance of sender's IP. if it is too far from the
    # source url domain, moderate/junk it.
    if ($config->{tborigin_mode} == 2) {
        $obj->moderate;
        return (0, MT->translate("Moderating: Domain IP does not match ping IP for source URL [_1]; domain IP: [_2]; ping IP: [_3]", $obj->source_url, $domainip, $pingip));
    }

    if ($config->{tborigin_mode} == 1) {
        return (-1 * $score,
            MT->translate("Domain IP does not match ping IP for source URL [_1]; domain IP: [_2]; ping IP: [_3]", $obj->source_url, $domainip, $pingip));
    }

    return (ABSTAIN);
}

sub urls {
    my $plugin = shift;
    my ($obj) = @_;

    my $config = $plugin->get_config_hash('blog:' . $obj->blog_id); # config($plugin);

    # URL tests...

    # count URLs...
    my $nurls = 0;
    my $text = $obj->all_text;
    my @domains = extract_domains($text, 0, \$nurls);

    if ($config->{urlcount_none_mode}) {
        return (int($config->{urlcount_none_weight}) || 1,
            MT->translate("No links are present in feedback")) unless $nurls;
    }

    my $domain;
    if (UNIVERSAL::isa($obj, 'MT::Comment')) {
        $domain = extract_domains($obj->url, 1);
    } elsif (UNIVERSAL::isa($obj, 'MT::TBPing')) {
        $domain = extract_domains($obj->source_url, 1);
    }

    my $pingip = $obj->ip;

    if (domain_or_ip_in_whitelist($nurls == 1 ? $domain : undef, $pingip, $config->{whitelist})) {
        return (ABSTAIN);
    }

    if ($config->{urlcount_junk_mode}) {
        if ($nurls >= $config->{urlcount_junk_limit}) {
            return (-1 * (int($config->{urlcount_junk_weight}) || 1),
                MT->translate("Number of links exceed junk limit ([_1])", $config->{urlcount_junk_limit}));
        }
    }

    if ($config->{urlcount_moderate_mode}) {
        if ($nurls >= $config->{urlcount_moderate_limit}) {
            $obj->moderate;
            return (0,
                MT->translate("Number of links exceed moderation limit ([_1])", $config->{urlcount_moderate_limit}));
        }
    }
    return (ABSTAIN);
}

sub link_memory {
    my $plugin = shift;
    my ($obj) = @_;

    my $config = $plugin->get_config_hash('blog:'.$obj->blog_id); # config($plugin);

    if ($config->{priorurl_mode}) {
        # this lookup is only effective on SQL databases since the
        # comment_url column is unindexed.
        if (!UNIVERSAL::isa(MT::Object->driver, 'MT::ObjectDriver::DBM')) {
            if (UNIVERSAL::isa($obj, 'MT::Comment')) {
                my @textdomains = extract_domains($obj->text);
                if (!@textdomains) {
                    my $url = $obj->url || '';
                    $url =~ s/^\s+|\s+$//gs;
                    if ($url =~ m!https?://\w+!) { # valid url requirement...
                        require MT::Comment;
                        my $terms = { url => $url,
                            blog_id => $obj->blog_id,
                            visible => 1 };
                        my $args;
                        if (my $grey = $config->{priorurl_greyperiod}) {
                            my $ts = time;
                            $ts -= $grey * (24 * 60 * 60);
                            require MT::Util;
                            $ts = MT::Util::epoch2ts($obj->blog_id, $ts);
                            $terms->{created_on} = [undef, $ts];
                            $args->{range_incl}{created_on} = 1;
                        }
                        my $c = MT::Comment->load($terms, $args);
                        if ($c) {
                            return ((int($config->{priorurl_weight}) || 1),
                                MT->translate("Link was previously published (comment id [_1]).", $c->id));
                        }
                    }
                }
            } elsif (UNIVERSAL::isa($obj, 'MT::TBPing')) {
                my $url = $obj->source_url || '';
                $url =~ s/^\s+|\s+$//gs;
                my $terms = { source_url => $url,
                    blog_id => $obj->blog_id,
                    visible => 1 };
                my $args;
                if ($config->{priorurl_greyperiod_mode}) {
                    my $grey = $config->{priorurl_greyperiod};
                    my $ts = time;
                    $ts -= $grey * (24 * 60 * 60);
                    require MT::Util;
                    $ts = MT::Util::epoch2ts($obj->blog_id, $ts);
                    $terms->{created_on} = [undef, $ts];
                    $args->{range_incl}{created_on} = 1;
                }
                my $t = MT::TBPing->load($terms, $args);
                if ($t) {
                    return ((int($config->{priorurl_weight}) || 1),
                        MT->translate("Link was previously published (TrackBack id [_1]).", $t->id));
                }
            }
        }
    }
    return (ABSTAIN);
}

sub email_memory {
    my $plugin = shift;
    my ($obj) = @_;

    my $config = $plugin->get_config_hash('blog:'. $obj->blog_id);

    if ($config->{prioremail_mode}) {
        # this lookup is only effective on SQL databases since the
        # comment_url collumn is unindexed.
        if (UNIVERSAL::isa($obj, 'MT::Comment')) {
            my $email = $obj->email;
            $email =~ s/^\s+|\s+$//gs;
            if ($email =~ m/\w+@\w+/) {
                require MT::Comment;
                my $terms = { email => $email,
                    blog_id => $obj->blog_id,
                    visible => 1 };
                my $args;
                if ($config->{prioremail_greyperiod}) {
                    my $grey = $config->{prioremail_greyperiod};
                    my $ts = time;
                    $ts -= $grey * (24 * 60 * 60);
                    require MT::Util;
                    $ts = MT::Util::epoch2ts($obj->blog_id, $ts);
                    $terms->{created_on} = [undef, $ts];
                    $args->{range_incl}{created_on} = 1;
                }
                my $c = MT::Comment->load($terms, $args);
                if ($c) {
                    return ((int($config->{prioremail_weight}) || 1),
                        MT->translate("E-mail was previously published (comment id [_1]).", $c->id));
                }
            }
        }
    }

    return (ABSTAIN);
}

sub wordfilter {
    my $plugin = shift;
    my ($obj) = @_;

    my $config = $plugin->get_config_hash('blog:'. $obj->blog_id);

    my $text = '';
    if (UNIVERSAL::isa($obj, 'MT::Comment')) {
        # Comment
        $text = join "\n",
            "name:". ($obj->author || ''),
            "email:" . ($obj->email || ''),
            "url:" . ($obj->url || ''),
            "text:" . ($obj->text || '');
    } else {
        # TrackBack ping
        $text = join "\n",
            "blog:". ($obj->blog_name || ''),
            "title:" . ($obj->title || ''),
            "url:" . ($obj->source_url || ''),
            "text:" . ($obj->excerpt || '');
    }

    my $decodedtext = decode_entities($text);
    $decodedtext = '' if $text eq $decodedtext;

    if ($config->{wordlist_junk}) {
        my @matches = wordlist_match($text, $config->{wordlist_junk});
        if (@matches && $decodedtext) {
            @matches = wordlist_match($decodedtext, $config->{wordlist_junk});
        }
        if (@matches) {
            my $total_score = 0;
            my @log;
            foreach (@matches) {
                my ($patt, $match, $score) = @$_;
                $total_score += $score;
                push @log, MT->translate("Word Filter match on '[_1]': '[_2]'.", $patt, $match);
            }
            return (-1 * ($total_score || 1), \@log);
        }
    }

    if ($config->{wordlist_moderate}) {
        my @matches = wordlist_match($text, $config->{wordlist_moderate});
        if (!@matches && $decodedtext) {
            @matches = wordlist_match($decodedtext, $config->{wordlist_moderate});
        }
        if (@matches) {
            my @log;
            foreach (@matches) {
                my ($patt, $match, $score) = @$_;
                push @log, MT->translate("Moderating for Word Filter match on '[_1]': '[_2]'.", $patt, $match);
            }
            $obj->moderate;
            return (0, \@log);
        }
    }

    return (ABSTAIN);
}

sub domainbl {
    my $plugin = shift;
    my ($obj) = @_;

    my $config = $plugin->get_config_hash('blog:' . $obj->blog_id); # config($plugin);
    return (ABSTAIN) unless $config->{domainbl_mode};

    my @domainbl_service = split /\s*,?\s+/, $config->{domainbl_service};
    return (ABSTAIN) unless @domainbl_service;

    my $text = $obj->all_text;
    my @domains = extract_domains($text);
    my $remote_ip = $obj->ip;

    if (domain_or_ip_in_whitelist(\@domains, $remote_ip, $config->{whitelist})) {
        return (ABSTAIN);
    }

    foreach my $domain (@domains) {
        next if $domain !~ m/\./;  # ignore domain if it is just a single word
        if ($domain =~ m/^(\d+)\.(\d+)\.(\d+)\.(\d+)$/) {
            $domain = "$4.$3.$2.$1";
        }
        foreach my $service (@domainbl_service) {
            $service =~ s/^\.//;
            $service =~ s/^\s+|\s+$//gs;
            if (checkdns("$domain.$service.")) {
                my $log = MT->translate("domain '[_1]' found on service [_2]", $domain, $service);
                if ($config->{domainbl_mode} == 2) {
                    $obj->moderate;
                    return (0, $log);
                } else {
                    return (-1 * (int($config->{domainbl_weight}) || 1), $log);
                }
            }
        }
    }
    return (ABSTAIN);
}

sub ipbl {
    my $plugin = shift;
    my ($obj) = @_;

    return (ABSTAIN) unless $obj->ip;

    my $config = $plugin->get_config_hash('blog:'. $obj->blog_id); # config($plugin);
    return (ABSTAIN) unless $config->{ipbl_mode};

    my $remote_ip = $obj->ip;

    if (domain_or_ip_in_whitelist(undef, $remote_ip, $config->{whitelist})) {
        return (ABSTAIN);
    }

    my ($a, $b, $c, $d) = split /\./, $remote_ip;
    return (ABSTAIN) unless $a && $b && $c &&$d;

    my @ipbl_service = split /\s*,?\s+/, $config->{ipbl_service};
    return (ABSTAIN) unless @ipbl_service;

    foreach my $service (@ipbl_service) {
        $service =~ s/^\.//;
        $service =~ s/^\s+|\s+$//gs;
        if (checkdns("$d.$c.$b.$a.$service.")) {
            my $log = MT->translate("[_1] found on service [_2]", $remote_ip, $service);
            if ($config->{ipbl_mode} == 2) {
                $obj->moderate;
                return (0, $log);
            } else {
                return (-1 * (int($config->{ipbl_weight}) || 1), $log);
            }
        }
    }
    return (ABSTAIN);
}

## Utility functions... not methods

sub checkdns {
    my ($name) = @_;
    if ($name =~ m/^\d+\.\d+\.\d+\.\d+$/) {
        return $name;
    }
    require MT::Request;
    my $cache = MT::Request->instance->cache('checkdns_cache') || {};
    return $cache->{$name} if exists $cache->{$name};
    my $iaddr = gethostbyname($name);
    return 0 unless $iaddr;
    require Socket;
    my $ip = Socket::inet_ntoa($iaddr);
    $cache->{$name} = $ip;
    MT::Request->instance->cache('checkdns_cache', $cache);
    return $ip ? $ip : undef;
}

sub reversedns {
    my ($ip) = @_;
    require MT::Request;
    my $cache = MT::Request->instance->cache('reversedns_cache') || {};
    return $cache->{$ip} if exists $cache->{$ip};
    require Socket;
    my $iaddr = Socket::inet_aton($ip);
    my $name = gethostbyaddr($iaddr, Socket::AF_INET());
    return undef unless $name;
    $cache->{$ip} = $name;
    MT::Request->instance->cache('reversedns_cache', $cache);
    return $name;
}

sub extract_domains {
    my ($str, $mode, $total) = @_;

    $mode ||= 0;
    # unmunge so we can see encoded urls as well
    $str = lc decode_entities($str);
    my @urls;
    my %seen;
    while ($str =~ m!(?:ht(?:tp)?s?:)?//(?:[a-z0-9\-\.\+:]+@)?([a-z0-9\.\-]+)!gi) {
        my $domain = $1;
        $domain =~ s/^\s+//s;
        $domain =~ s/\s+$//s;
        $domain =~ s/^www\.//s;
        next unless $domain;
        next unless $domain =~ m/\./;
        my @parts = split /\./, $domain;
        next unless @parts;
        if (($domain =~ m/^\d+\.\d+\.\d+\.\d+$/) || ($domain =~ m/^\d+$/)) {
            $$total++ if(defined($total));
            next if $seen{$domain};
            $seen{$domain} = 1;
            push @urls, $domain;
            next;
        }
        return $domain if $mode == 1;
        $$total++ if(defined($total));
        next if $seen{$domain};
        if ($mode == 0) {  # default mode, replicate for all subdomains
            my $last = $#parts;
            my $start = length($parts[$last]) < 3 ? 2 : 1;
            if ($start > $last) {
                $seen{$domain} = 1;
                push @urls, $domain;
            }
            foreach (my $i = $start; $i <= $last; $i++) {
                my $partial = join '.', @parts[$last - $i .. $last];
                next if $seen{$partial};
                $seen{$partial} = 1;
                push @urls, $partial;
            }
        } else {
            $seen{$domain} = 1;
            push @urls, $domain;
        }
    }

    @urls;
}

sub decode_entities {
    my ($str) = @_;
    if (eval { require HTML::Entities; 1 }) {
        return HTML::Entities::decode($str);
    } else {
        # yanked from HTML::Entities, since some users don't have the module
        my $c;
        for ($str) {
            s/(&\#(\d+);?)/$2 < 256 ? chr($2) : $1/eg;
            s/(&\#[xX]([0-9a-fA-F]+);?)/$c = hex($2); $c < 256 ? chr($c) : $1/eg;
        }
        $str;
    }
}

sub wordlist_match {
    my ($text, $patterns) = @_;

    $text ||= '';
    my @patt = split /[\r\n]+/, $patterns;
    my @matches;
    foreach my $patt (@patt) {
        next if $patt =~ m/^#/;
        my $score = 1;
        if ($patt =~ m/^(.*?) (\d+(?:\.\d+)?) *$/) {
            $patt = $1;
            $score = $2;
        }
        $patt =~ s/(^ +| +$)//g;
        next if $patt eq '';

        my $re_opt = MT::ConfigMgr->instance->DefaultLanguage eq 'ja' ? '' : '\b';
        if ($patt =~ m!^/!) {
            my $re = $patt;
            my ($opt) = $re =~ m!/([^/]*)$!;
            $re =~ s!^/!!;
            $re =~ s!/[^/]*$!!;
            if ($opt) {
                # increment any internal backreferences (\1),
                # since we're wrapping the whole expression in
                # a capturing group
                $re =~ s/ \\(\d+) / '\\' . ($1 + 1) /gex;

                $re = '(?' . $opt . ':' . $re . ')';
            }
            $re = eval { qr/($re)/ };
            $re = $re_opt . quotemeta($patt) . $re_opt if $@;
            push @matches, [ $patt, $1, int($score) ] if $text =~ m/($re)/;
        } else {
            my $re = $re_opt . quotemeta($patt) . $re_opt;
            push @matches, [ $patt, $1, int($score) ] if $text =~ m/($re)/i;
        }
    }
    @matches;
}

sub domain_or_ip_in_whitelist {
    my ($domain, $ip, $whitelist) = @_;

    if (ref $domain eq 'ARRAY') {
        my %domains;
        foreach my $domain (@$domain) {
            my @whitelist = split /\r?\n/, $whitelist;
            foreach my $whiteitem (@whitelist) {
                next if $whiteitem =~ m/^#/;
                if ($whiteitem =~ m/^\d{1,3}\.(?:\d{1,3}\.(?:\d{1,3}\.(?:\d{1,3})?)?)?$/) {
                    return 1 if defined $ip && ($ip =~ m/^\Q$whiteitem\E/);
                } elsif ($whiteitem =~ m/\w/) {
                    next if defined $domain && ($domain =~ m/\Q$whiteitem\E$/i);
                    $domains{$domain} = 1;
                }
            }
        }
        @$domain = keys %domains;
        return 0;
    }

    $whitelist ||= '';
    my @whitelist = split /\r?\n/, $whitelist;
    foreach my $whiteitem (@whitelist) {
        next if $whiteitem =~ m/^#/;
        if ($whiteitem =~ m/^\d{1,3}\.(?:\d{1,3}\.(?:\d{1,3}\.(?:\d{1,3})?)?)?$/) {
            return 1 if defined $ip && ($ip =~ m/^\Q$whiteitem\E/);
        } elsif ($whiteitem =~ m/\w/) {
            return 1 if defined $domain && ($domain =~ m/\Q$whiteitem\E$/i);
        }
    }

    return 0;
}

1;
