#!/usr/local/bin/perl

# 2007-07-22 v0.01
# License : Same as Perl
# Sample : http://blog.bulkneets.net/misc/ustream/channel2json.pl

use strict;
use CGI;
use LWP::UserAgent;
use Cache::FileCache;
use URI::Fetch;
use JSON::Syck;

my $q = CGI->new;

my $cache = Cache::FileCache->new({
    'cache_root' => '.cache',
    'namespace'  => 'ustream2json',
    'default_expires_in' => 3600
});

my $channel_name = $q->param("channel_name");
# $channel_name = "yappo,mala";
my @channels = split(/,/, $channel_name);

if (scalar @channels > 30){
    output_json($q, "too large");
}

my %result = map {
    $_ => channel2usc($_) 
} map {
    $_=~s{http://www.ustream.tv/channel/}{}; $_ 
} @channels;

output_json($q, \%result);

sub channel2usc {
    my $channel = shift;
    my $url = "http://www.ustream.tv/channel/" . $channel;
    my $ua = LWP::UserAgent->new;
    $ua->agent('ustream2json/0.01');
    
    my $res = URI::Fetch->fetch(
        $url,
        UserAgent => $ua,
        Cache     => $cache,
        NoNetwork => 3600
    );

    return undef unless $res->is_success;
    my $content = $res->content;
    $content =~m{src="http://www.ustream.tv/([^"]*?).usc"};
    return $1 ? $1 : undef;
}

sub output_json {
    my ($q, $obj) = @_;
    print $q->header(
        "-type" => "text/javascript",
        "-charset" => 'utf-8'
    );
    my $json = JSON::Syck::Dump($obj);
    if(defined (my $p = $q->param('callback'))){
        $json = "$p($json);" if($p =~ /[a-zA-Z0-9\.\_\[\]]/);
    }
    print $json;
}