#! /perl/bin/perl -w

use strict;
use CGI();
use CGI::Carp qw(fatalsToBrowser warningsToBrowser);
use LWP::Simple;
use XML::Parser;

use vars qw(
	$q
	$TITLE
	$URL
	$NODETYPE_TITLES
	$NODETYPES_TO_SHOW_FIRST
	$NODETYPES_TO_IGNORE
	$SHOW_AUTHOR
	$xml_source_link
	$nodes_by_type $current_node $current_node_char
	$authors
	$info
);

main();

sub main {
	init();
	get_and_parse_xml();
	print
		  $q->header
		, $q->start_html({-title => $TITLE})
		, $q->h1($TITLE)
		, $q->i($info->{cdata})
		, (' ' x 4) . $xml_source_link
	;
	nodes_to_html();
	ignored_nodes_html();
	print $q->end_html;
}

sub init {
	$| = 1;
	$q = CGI->new;
	$URL = "http://www.perlmonks.org/index.pl?node=Newest%20Nodes%20XML%20Generator";
	$xml_source_link = $q->a({-href => "view-source:$URL"}, 'View the XML Source');
	$TITLE = "Perl Monks - Newest Nodes via XML";
	$NODETYPE_TITLES = {
		  perlquestion => "Questions"
		, perlmeditation => "Meditations"
		, user => "Users"
		, note => "Notes"
		, sourcecode => "Code"
		, CUFP => "Cool Uses For Perl"
		, poem => "Poetry"
		, perltutorial => "Tutorials"
		, modulereview => "Module Reviews"
		, obfuscated => "Obfuscation"
		, "categorized question" => "Categorized Questions"
		, "categorized answer" => "Categorized Answers"
		, "monkdiscuss" => "Discussion"
	};
	$NODETYPES_TO_SHOW_FIRST = [
		  "perlquestion"
		, "perlmeditation"
		, "monkdiscuss"
		, "CUFP"
		, "sourcecode"
		, "modulereview"
		, "poem"
		, "categorized question"
		, "categorized answer"
	];
	$NODETYPES_TO_IGNORE = [
		  "user"
		, "note"
		, "obfuscated"
	];
	$SHOW_AUTHOR = 1;
	$nodes_by_type = {};
	$authors = {};
}

####
# subs for parsing xml, handling tags, etc.
####

sub get_and_parse_xml {
	my $xml = get($URL) || die " couldn't get xml";
	my $p = XML::Parser->new (
		Handlers =>{
		Start => \&start_tag,
        End   => \&end_tag,
        Char  => \&char_data
    },) || die "Couldn't create new Parser";
	eval { $p->parse($xml) };
	die "couldn't parse: $@" if $@;
}
sub start_tag {
	my ($p, $el, %attrs) = @_;
	$current_node = {};
	%$current_node = %attrs;
	$current_node_char = '';
}
sub end_tag {
	my ($p, $el) = @_;
	$current_node->{cdata} = $current_node_char;
	INFO_tag() if $el eq 'INFO';
	NODE_tag() if $el eq 'NODE';
	AUTHOR_tag() if $el eq 'AUTHOR';
}
sub char_data {
	my ($p, $string) = @_;
	$current_node_char .= $string;
}
sub INFO_tag {
	$info = $current_node;
}
sub NODE_tag {
	my $nodetype = $current_node->{nodetype};
	push(@{$nodes_by_type->{$nodetype}}, $current_node);	
}
sub AUTHOR_tag {
	my $author_id = $current_node->{node_id};
	my $author_name = $current_node->{cdata};
	$authors->{$author_id} = $author_name;
}

###
# subs for taking parsed nodes and generating html
####

sub nodes_to_html {
	my $html = '';
	foreach my $nodetype (@$NODETYPES_TO_SHOW_FIRST) {
		$html .= html_by_type($nodetype);
		delete $nodes_by_type->{$nodetype};
	}
	foreach my $nodetype (@$NODETYPES_TO_IGNORE) {
		delete $nodes_by_type->{$nodetype};
	}
	foreach my $nodetype (keys %$nodes_by_type) {
		$html .= html_by_type($nodetype);
	}
}

sub html_by_type {
	my $nodetype = shift;
	print $q->h2( node_title($nodetype) );
	my $nodes = $nodes_by_type->{$nodetype} || [];
	unless (@$nodes) {
		print $q->ul($q->li('No nodes') );
		return;
	}
	my $url_base = 'http://www.perlmonks.org/?node_id=';
	print '<ul>';
	foreach my $node (@$nodes) {
		my $link = $q->a({-href => "$url_base$node->{node_id}"}, $node->{cdata});
		my $node_text = $q->li($link);
		my $author = $authors->{$node->{author_user}};
		$node_text .= ('&nbsp;' x 2) . $q->small(" by $author") if $SHOW_AUTHOR;
		print $node_text;
	}
	print '</ul>';
}

sub ignored_nodes_html {
	my $html = '';
	foreach my $ignore_type (@$NODETYPES_TO_IGNORE) {
		$html .= $q->li( node_title($ignore_type) );
	}
	return unless $html;
	print $q->h2('Ignored Node Types')
		, $q->ul($html)
	;
}

sub node_title { $NODETYPE_TITLES->{$_[0]} || $_[0] }