var Stream = require('stream');
var sockjs = require('sockjs-client');
var resolve = require('url').resolve;
var parse = require('url').parse;

module.exports = function (u, cb) {
    var uri = parse(u).protocol ? u : resolve(window.location.href, u);
    
    var stream = new Stream;
    stream.readable = true;
    stream.writable = true;
    
    var ready = false;
    var buffer = [];
    
    var sock = sockjs(uri);
    stream.sock = sock;
    
    stream.write = function (msg) {
        if (!ready || buffer.length) buffer.push(msg)
        else sock.send(msg)
    };
    
    stream.end = function (msg) {
        if (msg !== undefined) stream.write(msg);
        if (!ready) {
            stream._ended = true;
            return;
        }
        stream.writable = false;
        sock.close();
    };
    
    stream.destroy = function () {
        stream._ended = true;
        stream.writable = stream.readable = false;
        buffer.length = 0
        sock.close();
    };
    
    sock.onopen = function () {
        if (typeof cb === 'function') cb();
        ready = true;
        for (var i = 0; i < buffer.length; i++) {
            sock.send(buffer[i]);
        }
        buffer = [];
        stream.emit('connect');
        if (stream._ended) stream.end();
    };
    
    sock.onmessage = function (e) {
        stream.emit('data', e.data);
    };
    
    sock.onclose = function () {
        stream.emit('end');
        stream.writable = false;
        stream.readable = false;
    };
    
    return stream;
};