#!/usr/bin/perl -w
use strict;
# vim: sw=4 et ts=4

# how to use:
#
#   google   "some words, and more words"
#   will google this:  "some words" "and more words"
#
$|=1;
use HTTP::Request::Common qw(POST GET);
use LWP::Simple;
use LWP::UserAgent;
use Getopt::Long;
sub usage {
    return <<__EOF__
Usage: google [-c] [-a] "search string1,word2" "search string2,word3"
  will do 2 google queries: ( quotes are always added )
  "search string1" "word2"
  "search string2" "word3"
options:
   -a  return all result pages, instead of only the first 100 results.
   -c  just print the count
   -v  verbose: print query
__EOF__
}
my $allpages;
my $countonly;
my $verbose;
GetOptions(
    "a"=>\$allpages,
    "c"=>\$countonly,
    "v"=>\$verbose,
) or die usage();

my $ua= LWP::UserAgent->new();
$ua->agent("Mozilla/4.75 [en] (X11; U; Linux 2.2.17 i686)");

binmode STDOUT, ":utf8";

for my $query (@ARGV) {
    my $pagenr=0;
    my $empty=0;
    my %urls;
    while ($pagenr==0 || $allpages && $empty<2) {
        my $googlehtml;
        if ($query eq "-") {
            if ($pagenr==0) {
                $googlehtml= join "\n", <>;
            }
            else {
                $googlehtml= "";
            }
        }
        else {
            $googlehtml = QueryGoogle($query, $pagenr);
        }
        if ($countonly) {
            printf("%12d %s\n", ParseCount($googlehtml), $query);
        }
        else {
            my $result= ParseGoogle($googlehtml);

            my $oldcount=scalar keys %urls;
            $urls{$_->{url}}++ for @$result;
            my $newcount=scalar keys %urls;

            PrintResult($result) if ($oldcount!=$newcount);

            $empty= ($oldcount!=$newcount) ? 0 : $empty+1;
        }
        $pagenr++;
    }
    if (!$countonly) {
        printf("\n\ntotal %d pages\n", $pagenr);
    }
}

exit(0);

sub uniq {
    my ($list)= @_;
    my %ref;
    $ref{$_}++ for (@$list);
    return [keys %ref];
}

sub QueryGoogle {
    my ($query, $pagenr)= @_;
    $query= join " ", map { (/^\w+:/)?$_:"\"$_\""  } split /\s*,\s*/, $query;

    $query=~ s/[&?%+]/sprintf("%%%02x", ord($&))/egs;
    $query =~ s/ /+/gs;

    $query =~ s/,\s*/"+"/g;
    my $num= $countonly ? 10 : 100;
    if ($pagenr==0 && $verbose) {
        print "query: $query\n";
    }
    my $pagerq= GET sprintf("http://www.google.com/search?q=%s&num=${num}&hl=en&safe=off&btnG=Search&start=%d", $query, $pagenr*100);
#    print $pagerq->as_string;
    my $rp= $ua->request($pagerq);

    return $rp->content;
}
sub GetQuery {
    my ($parts, $qid)= @_;

    my $query="";

    for my $part (@$parts) {
        my $n_choices= scalar @$part;
        my $choice= $qid%$n_choices;
        $qid= int($qid/$n_choices);
        $query .= $part->[$choice];
    }
    return $query;
}

sub getTotalChoices {
    my ($parts)= @_;
    my $total= 1;
    for my $part (@$parts) {
        my $n_choices= scalar @$part;
        $total *= $n_choices;
    }
    return $total;
}

sub ParseGoogle {
    my ($html)= @_;

    my @result;
    my @parts= split(/<br><div|<p>/, $html);
    for my $part (@parts) {
        next if ($part !~ /href/);
        #next if ($part =~ /Did you mean(?: to search for)?:.*\/search/);
        #next if ($part =~ /Category:.*href=.*directory.google.com/);
        #next if ($part =~ /Result.*?Search took.*?second/i);
        return [] if ($part =~ /<br>Your search - <b>.*?<\/b> - did not match any documents/is);
        my ($url)= ($part =~ /<a href="(.*?)"/is);
        next if $url =~ /google.com\/accounts\/Login/;
        my ($title)= ($part =~ /(?:class=l>|<a[^>]+>)(.*?)<\/a>/is);
        $title =~ s/\s+/ /gs if ($title);
        $title =~ s/\s+</</gs if ($title);
        $title =~ s/>\s+/>/gs if ($title);
        my ($desc)= ($part =~ /<td class="j\s*\w*">\s*<font size="?-1"?>(.*?)(?:<span class=a>|<font color="green">)/is);
        $desc =~ s/\s+/ /gs if ($desc);
        $desc =~ s/\s+</</gs if ($desc);
        $desc =~ s/>\s+/>/gs if ($desc);

        push @result, {url=>$url, title=>decodehtml($title), desc=>decodehtml($desc)};
    }
    return \@result;
}
sub ParseCount {
    my ($html)= @_;
#    print $html;
    if ($html=~/swrnum=(\d+)"/i) {
        return $1;
    }
    elsif ($html =~ /of about\s*<b>(.*?)<\/b>/) {
        my $n= $1;
        $n =~ s/,//g;
        return $n;
    }
    return 0;
}
sub decodehtml {
    my $str= shift;
    return "" unless defined $str;
    $str =~ s/<\/?b>//gi;
    $str =~ s/<br>\r*/\n\t/gi;
    $str =~ s/<span class=f>.*?<\/a>//; # strips 'view as html'
    $str =~ s/\t$//;
    $str =~ s/&lt;/</g;
    $str =~ s/&gt;/>/g;
    $str =~ s/&quot;/"/g;
    $str =~ s/&#(\d+);/chr($1)/ge;
    $str =~ s/&amp;/&/g;
    return $str;
}
sub PrintResult {
    my ($results) = @_;
    for my $r (@$results) {
        print "$r->{url}\n\t$r->{title}\n\t$r->{desc}\n";
    }
}