package VROOM::Search::Google;

use strict;

use VROOM::Search qw(escape_query unescape_sequence);
use Time::HiRes   qw(gettimeofday);

@VROOM::Search::Google::ISA = qw(VROOM::Search);

sub prepare_request
{
    my $self   = shift;
    my $query  = escape_query(shift);
    my $params = shift;
    my $uri    = 'http://www.google.com';

    $params->{baseurl} = $uri unless defined $params->{baseurl};
    $params->{hl}      = 'en' unless defined $params->{hl};

    $self->{baseurl} = $uri = $params->{baseurl};

    $uri .= '/search?q='.$query;

    while (my ($name, $value) = each %$params) {
	next if $name =~ /baseurl/;
	$uri .= '&'.$name.'='.$value;
    }

    $self->{initime} = $self->{endtime} = [gettimeofday];

    $self->{request} = new HTTP::Request(GET => $uri);
}

sub store_results
{
    my $self = shift;
    my $res  = shift;

    $self->{endtime} = [gettimeofday];

    if ($res->code != 200) {
	$self->{request} = undef;
	return undef;
    }

    #
    # Google doesn't return Content-Length, 
    # so ($res->headers)->content_length will be zero. We're forced to
    # use Perl function - length.
    #
    $self->{fetch}++;
    $self->{pgsize} += length($res->content);

    #
    # If we reach here, HTTP response is OK. Proceed to parse the html
    # document for search results
    #
    my ($HIT, $ENTRY, $NEXT) = (0, 1, 2);
    my $rank   = $self->count;
    my $hits   = 0;
    my $wish   = $HIT;
    my $result = undef;
    
    foreach (split(/(<p>|\n|<\/div>)/i, $res->content)) {
        next if /^$/;			# short circuit for blank lines
	last if $wish == $NEXT;
	
	if ($self->count == $self->maximum) {
	    $self->{request} = undef;
	    return $hits;
	}

	#print "#################################################\n";
	#print $_, "\n";

	#
	# Ah,found some results. Get approximate results and wish to 
        # see the title/url of the first result.
	# 
	if ($wish == $HIT && /Results.*?of.*?([0-9,]+).*?\./i) {
	    my $count = $1;
	    $self->approximate($count);
	    $wish = $ENTRY;
	}
	#
	# Extract the url/title and wish to have abstract text
	#
	elsif ($wish == $ENTRY && 
	       /^<a href=(.*?)>(.*?)<\/a><br><font.*?>(.*?)$/i) {
	    
	    my $url      = $1;
	    my $title    = $2;
	    my $abstract = $3;

	    $url    =~ s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg;
	    $url    =~ s/(^http:\/\/|\/(index.htm|index.html)*$)//g;
	    $title  =~ s/<.*?>//g;
 
	    $result = new VROOM::Search::Result;
	    $result->url($url);
	    $result->title(unescape_sequence($title));
	    $result->text(unescape_sequence($abstract));
	    $result->rank(++$rank);
	    $result->engine('Google');

	    $self->add_result($result);
	    $self->{pool}->insert($result) if $self->{pool};
	    $hits++;
        }
	#
	# Extract the url for the next page
	#
	elsif ($wish == $ENTRY && 
	       /<td nowrap><a href=(.*?)>.*?<span.*?>Next<\/span><\/a>/i) {

	    $self->{request}->uri($self->{baseurl}.$1);

	    $wish = $NEXT;
	}
    }

    #
    # This is important. It signals the search agent not to fetch more pages.
    #
    $self->{request} = undef if $wish != $NEXT;


    return $hits;
    
}

1;

__END__