/**
 * Simulates an XMLHttpRequest object's methods and properties but is backed by a
 * {@link Ext.ux.ajax.Simlet} instance that provides the data.
 */
Ext.define('Ext.ux.ajax.SimXhr', {
    readyState: 0,

    mgr: null,
    simlet: null,

    constructor: function(config) {
        var me = this;

        Ext.apply(me, config);
        me.requestHeaders = {};
    },

    abort: function() {
        var me = this;

        if (me.timer) {
            Ext.undefer(me.timer);
            me.timer = null;
        }

        me.aborted = true;
    },

    getAllResponseHeaders: function() {
        var headers = [];

        if (Ext.isObject(this.responseHeaders)) {
            Ext.Object.each(this.responseHeaders, function(name, value) {
                headers.push(name + ': ' + value);
            });
        }

        return headers.join('\x0d\x0a');
    },

    getResponseHeader: function(header) {
        var headers = this.responseHeaders;

        return (headers && headers[header]) || null;
    },

    open: function(method, url, async, user, password) {
        var me = this;

        me.method = method;
        me.url = url;
        me.async = async !== false;
        me.user = user;
        me.password = password;

        me.setReadyState(1);
    },

    overrideMimeType: function(mimeType) {
        this.mimeType = mimeType;
    },

    schedule: function() {
        var me = this,
            delay = me.simlet.delay || me.mgr.delay;

        if (delay) {
            me.timer = Ext.defer(function() {
                me.onTick();
            }, delay);
        }
        else {
            me.onTick();
        }
    },

    send: function(body) {
        var me = this;

        me.body = body;

        if (me.async) {
            me.schedule();
        }
        else {
            me.onComplete();
        }
    },

    setReadyState: function(state) {
        var me = this;

        if (me.readyState !== state) {
            me.readyState = state;
            me.onreadystatechange();
        }
    },

    setRequestHeader: function(header, value) {
        this.requestHeaders[header] = value;
    },

    // handlers

    onreadystatechange: Ext.emptyFn,

    onComplete: function() {
        var me = this,
            callback, text;

        me.readyState = 4;
        Ext.apply(me, me.simlet.exec(me));

        callback = me.jsonpCallback;

        if (callback) {
            text = callback + '(' + me.responseText + ')';

            eval(text);
        }
    },

    onTick: function() {
        var me = this;

        me.timer = null;
        me.onComplete();

        if (me.onreadystatechange) {
            me.onreadystatechange();
        }
    }
});
