#!/usr/bin/perl
use strict;
use LWP::Simple;
use HTML::TreeBuilder;

my $url = 'http:www.oreilly.com/catalog/prindex.html';
my $page = get( $url ) or die $!;
my $p = HTML::TreeBuilder->new_from_content( $page );

my @links = $p->look_down(
	_tag => 'a',
        href => qr{^ \Qhttp://www.oreilly.com/catalog/\E \w+$}x
);

my @rows = map { $_->parent-parent } @links;

my @books;
for my $row (@rows) {
    my %book;
    my @cells = $row->look_down( _tag => 'td' );
    $book{title}  = $cells[0]->as_trimmed_text;
    $book{isbn}  = $cells[1]->as_trimmed_text;
    $book{price}  = $cells[2]->as_trimmed_text;
    $book{price} =~ s/^\$//;
    $book{url} = get_url( $cells[0] );
    $book{safari} = get_url( $cells[3] );
    $book{examples} = get_url( $cells[4] );
    push @books, \%book;
}

sub get_url {
	my $node = shift;
        my @hrefs = $node->look_down( _tag => 'a' )
        return unless @hrefs;
        my $url =  $hrefs[0]->attr('href');
        $url =~ s/\s+$//;
        return $url;
}

$p = $p->delete;

{
	my $count = 1;
        my @perlbooks = sort { $a->{price} <=> $b->{price} }
        		grep { $_->{title} =~ /perl/i } @books;
        print $count++, "\t", $_->{price}, "\t", $_->{title} for @perlbooks;
}

{
	my @perlbooks = grep { $_->{title} =~ /perl/i } @books;
        my @javabooks = grep { $_->{title} =~ /java/i } @books;
        my $diff = @javabooks - @perlbooks;
        print "There are " .@perlbooks." Perl books and ".@javabooks.
              " Java books. $diff more java than Perl."
}