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/**
 * @fileOverview HttpStreamModel Module
 * @version 1.0
 */

define(['jquery'], function($) {

    require(['bind']);

    'use strict';

    var url;

    var HttpStreamModel = {

        XHR_READY_STATE_REQUEST_RECEIVED: 2,
        listeners: [],

        setUrl: function(url) {
          url = url;  
        },

        openStream: function() {

            if (typeof window.XDomainRequest === 'undefined') {
                this._openStreamXHR();
            } else {
                this._openStreamXDR();
            }
        },

        /**
         * Legacy IE
         */
        _openStreamXDR: function() {
            try {
                var xdr = new XDomainRequest();
                xdr.open("GET", url);
                xdr.send();

                xdr.onload = function() {
                    // ... would only get here if the connection closes
                };

                xdr.onerror = function() {
                    // error handline
                };

                xdr.onprogress = function() {
                    this.setResponse(xdr.responseText);
                    this.parseResponse();
                    this.notifyListeners();
                }.bind(this);
            } catch (e) {
                this.log("[XDR] Exception: " + e);
            }

        },

        /**
         * Modern Browsers
         */
        _openStreamXHR: function() {
            var xhr = new XMLHttpRequest();

            xhr.onload = function() {
                // since our connection doesn't close, there's nothing to handle here
            };

            xhr.onerror = function() {
                // error handling
            };

            xhr.onreadystatechange = function() {
                try {
                    if (xhr.readyState > this.XHR_READY_STATE_REQUEST_RECEIVED) {
                        this.setResponse(xhr.responseText);
                        this.parseResponse();
                        this.notifyListeners();
                    }
                }
                catch (e){
                    // exception handling
                }
            }.bind(this);

            xhr.open("GET", url, true);
            xhr.send("Making request...");

        },

        setResponse: function(response) {
            this.response = response;
        },

        /**
         * The feed is not valid json, so we need to treat it as text, parse out the last object, and decode it to
         * an object
         */
        parseResponse: function() {
            var lastObjectIndex = this.response.lastIndexOf("{");
            var substring = $.trim(this.response.substring(lastObjectIndex)).replace(/(\r\n|\n|\r)/gm, "");
            if (substring.length) {
                try {
                    var latest = $.parseJSON(substring);
                    if (typeof latest !== 'undefined') {
                        this.latest = latest;
                    }
                } catch (e) {
                    // silent
                }

            }
        },

        notifyListeners: function() {
            if (typeof this.latest !== 'undefined') {
                for (var listener in this.listeners) {
                    if (typeof this.listeners[listener] === 'function') {
                        this.listeners[listener](this.latest);
                    }
                }
            }
        },

        addListener: function(listener) {
            if (typeof listener === 'function') {
                this.listeners.push(listener);
            }
        },

        log: function(msg) {
            if (window.XDomainRequest) {
                alert(msg);
            } else {
                console.log(msg);
            }
        }
    };

    return HttpStreamModel;
});