#!/usr/bin/perl
use warnings;
use strict;

use JSON::XS;
use EV;
use Scalar::Util qw/weaken/;
use HTML::Entities qw/encode_entities/;
use URI::Escape qw/uri_unescape/;

my $clients = 0;
my @handles;
my @timers;

my @html_hdrs = (
    'Content-Type' => 'text/html; charset=UTF-8',
    'Cache-Control' => 'no-cache, no-store, private',
    'Pragma' => 'no-cache',
);

sub show_chat {
    my ($r,$client) = @_;

    $r->send_response(200, \@html_hdrs, <<EOHTML);

Chat!

EOHTML
}

sub show_form {
    my ($r, $client, $nick) = @_;
    $r->send_response(200, \@html_hdrs, <<EOHTML);

Chat!

    Nick: 
    Say: 

EOHTML
}

sub start_stream {
    my ($r, $client) = @_;
    my $w = $r->start_streaming(200, \@html_hdrs);
    $handles[$client] = $w;
    weaken $w;
    $timers[$client] = EV::timer 1,1,sub {
        $w->write('') if $w;
    };
    $w->write(<<EOH);

Hello! (connection $client)
EOH
}

sub broadcast {
    my $kv = shift;
    my $client = $kv->{client};

    $kv->{nick} ||= "anon$client";
    $kv->{nick} = encode_entities(uri_unescape($kv->{nick}));

    $kv->{say} ||= '*wants to say something*';
    $kv->{say} = encode_entities(uri_unescape($kv->{say}));

    my $msg = \"<p><b>$kv->{nick}</b>: $kv->{say}</p>";
    warn $$msg."\n";

    for my $i (1 .. $clients) {
        my $w = $handles[$i];
        next unless $w;
        eval { $w->write($msg) };
        if ($@) { warn $@; $handles[$i] = undef }
    }
}

my $app = sub {
    my $r = shift;
    my $env = $r->env;
    my $path = $env->{PATH_INFO};
    if ($path eq '/post' && $env->{REQUEST_METHOD} eq 'POST') {
        my $input = delete $env->{'psgi.input'};
        my $body = '';
        $input->read($body, $env->{CONTENT_LENGTH});
        my %kv = map { split('=',$_,2) } split('&',$body);
        my $t; $t = EV::timer 0.00001, 0, sub{
            broadcast(\%kv);
            undef $t;
        };
        show_form($r,$kv{client},$kv{nick});
    }
    elsif ($path =~ m{^/form/(\d+)$}) {
        my $client = $1;
        show_form($r,$client,'');
    }
    elsif ($path =~ m{^/chat/(\d+)$}) {
        my $client = $1;
        start_stream($r,$client);
    }
    else {
        my $client = ++$clients;
        show_chat($r,$client);
    }
};
