/*
Copyright (c) 2005  Vitaliy Shevchuk (shevit@users.sourceforge.net)

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

*/

AjaxAnywhere.defaultInstanceName = "default";
// constructor;
function AjaxAnywhere() {

    this.id = AjaxAnywhere.defaultInstanceName;
    this.formName = null;

    if (window.XMLHttpRequest) {
        this.req = new XMLHttpRequest();
    } else if (window.ActiveXObject) {
        this.req = new ActiveXObject("Microsoft.XMLHTTP");
    }

}

/**
* Returns a Form object that corresponds to formName property of this AjaxAnywhere class instance.
*/
AjaxAnywhere.prototype.findForm = function () {
    var form;
    if (this.formName != null)
        form = document.forms[this.formName];
    else if (document.forms.length > 0)
        form = document.forms[0];

    if (typeof form != "object")
        alert("AjaxAnywhere error: Form with name [" + this.formName + "] not found");
    return form;
}

/**
* Binds this instance to window object using "AjaxAnywhere."+this.id as a key.
*/
AjaxAnywhere.prototype.bindById = function () {
    var key = "AjaxAnywhere." + this.id;
    window[key] = this;
}

/**
* Finds an instance by id.
*/
AjaxAnywhere.findInstance = function(id) {
    var key = "AjaxAnywhere." + id;
    return window[key];
}

/**
* This function is used to submit all form fields by AJAX resuest to the server.
*/
AjaxAnywhere.prototype.submitAJAX = function(additionalPostData) {

    if (typeof additionalPostData == "undefined")
        additionalPostData = "";

    this.bindById();

    var form = this.findForm();
    var url = form.action;
    if (url == "")
        url = location.href;

    var zones = this.getZonesToReaload(url);

    if (zones == null) {
        if (typeof form.submit_old == "undefined")
            form.submit();
        else
            form.submit_old();
        return;
    }

    this.dropPreviousRequest();

    this.req.open("POST", url, true);
    this.req.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");

    var postData = this.preparePostData();

    if (zones != "")
        postData = '&aazones=' + escape(zones) + "&" + postData + "&" + additionalPostData;
    else
        postData += "&" + additionalPostData;

    this.sendPreparedRequest(postData);

}
/**
* sends a GET request to the server.
*/
AjaxAnywhere.prototype.getAJAX = function(url) {

    this.bindById();

    var zones = this.getZonesToReaload(url);

    this.dropPreviousRequest();

    url += (url.indexOf("?") != -1) ? "&" : "?";

    url += "aa_rand=" + Math.random(); // avoid caching

    if (zones != null && zones != "")
        url += '&aazones=' + escape(zones);

    this.req.open("GET", url, true);

    this.sendPreparedRequest("");
}

/**
* @private
*/
AjaxAnywhere.prototype.sendPreparedRequest = function (postData){
    var callbackKey = this.id + "_callbackFunction";
    if (typeof window[callbackKey] == "undefined")
        window[callbackKey] = new Function("AjaxAnywhere.findInstance(\"" + this.id + "\").callback(); ");
    this.req.onreadystatechange = window[callbackKey];

    this.showLoadingMessage();
    this.req.setRequestHeader("aaxmlrequest","true");
    this.req.send(postData);
}
/**
* Used internally by AjaxAnywhere. Aborts previous request if not completed.
*/
AjaxAnywhere.prototype.dropPreviousRequest = function() {
    if (this.req.readyState != 0 && this.req.readyState != 4) {
        // abort previous request if not completed
        this.req.abort();
        this.handlePrevousRequestAborted();
    }
}

/**
* Internally used to prepare Post data
*/
AjaxAnywhere.prototype.preparePostData = function() {
    var form = this.findForm();
    var result = "";
    for (var i = 0; i < form.elements.length; i++) {
        var el = form.elements[i];
        if (el.tagName.toLowerCase() == "select") {
            for (var j = 0; j < el.options.length; j++) {
                var op = el.options[j];
                if (op.selected)
                    result += "&" + el.name + "=" + escape(op.value);
            }
        } else if (el.type.toLowerCase() == "checkbox" || el.type.toLowerCase() == "radio") {
            if (el.checked)
                result += "&" + el.name + "=" + escape(el.value);
        } else if (el.type.toLowerCase() != "submit" && el.type.toLowerCase() != "button") {
            result += "&" + el.name + "=" + escape(el.value);
        }
    }
    return result;
}

/**
* A callback. internally used
*/
AjaxAnywhere.prototype.callback = function() {

    if (this.req.readyState == 4) {

        this.onBeforeResponseProcessing();
        this.hideLoadingMessage();

        if (this.req.status == 200) {

            var docs = this.req.responseXML.getElementsByTagName("document");
            var redirects = this.req.responseXML.getElementsByTagName("redirect");
            var zones = this.req.responseXML.getElementsByTagName("zone");
            var exceptions = this.req.responseXML.getElementsByTagName("exception");
            var scripts = this.req.responseXML.getElementsByTagName("script");

            if (redirects.length != 0) {
                var newURL = redirects[0].firstChild.data;
                location.href = newURL;
            }
            if (docs.length != 0) {
                var newContent = docs[0].firstChild.data;

                //cleanup ressources
                delete this.req;

                document.close();
                document.write(newContent);
                document.close();
            }
            if (zones.length != 0) {
                for (var i = 0; i < zones.length; i++) {
                    var zoneNode = zones[i];
                    var name = zoneNode.getAttribute("name");
                    var fc = zoneNode.firstChild;
                    if (fc == null)
                        continue;

                    var html = fc.data;
                    var zoneHolder = document.getElementById("aazone." + name);
                    if (typeof(zoneHolder) != "undefined") {
                        zoneHolder.innerHTML = html;
                    }

                }
            }
            if (exceptions.length != 0) {
                var e = exceptions[0];
                var type = e.getAttribute("type");
                var stackTrace = e.firstChild.data;
                this.handleException(type, stackTrace);
            }

            if (scripts.length != 0) {
                for (var i = 0; i < scripts.length; i++) {
                    var script = scripts[i].firstChild;
                    if (script != null) {
                        script = script.data;
                        if (script.indexOf("document.write") != -1) {
                            this.handleException("document.write", "This script contains document.write(), which is not compatible with AjaxAnywhere : \n\n" + script);
                        } else {
                            eval(script);
                        }
                    }
                }

                var globals = this.getGlobalScriptsDeclarationsList(script);
                if (globals != null)
                    for (var i in globals) {
                        var objName = globals[i];
                        try {
                            window[objName] = eval(objName);
                        } catch(e) {
                        }
                    }
            }

        } else {
            if (this.req.status != 0)
                this.handleHttpErrorCode(this.req.status);
        }
        this.onAfterResponseProcessing();

    }


}

/**
*  Default sample loading message shuw function. Overrride it if you like.
*/
AjaxAnywhere.prototype.showLoadingMessage = function() {

    var div = document.getElementById("AA_" + this.id + "_loading_div");
    if (div == null) {
        div = document.createElement("DIV");

        document.body.appendChild(div);
        div.id = "AA_" + this.id + "_loading_div";

        div.innerHTML = "Loading...";
        div.style.position = "absolute";
        div.style.border = "1 solid black";
        div.style.color = "white";
        div.style.backgroundColor = "red";
        div.style.padding = "0px 5px";
        div.style.top = 0;
        div.style.right = 0;
        div.style.fontSize = "12px";
    }

    div.style.display = "";
}

/**
*  Default sample loading message hide function. Overrride it if you like.
*/
AjaxAnywhere.prototype.hideLoadingMessage = function() {
    var div = document.getElementById("AA_" + this.id + "_loading_div");
    if (div != null)
        div.style.display = "none";

}

/**
* This function is used to facilitatte AjaxAnywhere integration with existing projects/frameworks.
* It substitutes default Form.sumbit().
* The new implementation calls AjaxAnywhere.isFormSubmitByAjax() function to find out if the form
* should be submitted in traditional way or by AjaxAnywhere.
*/
AjaxAnywhere.prototype.substituteFormSubmitFunction = function() {

    this.bindById();

    var form = this.findForm();

    form.submit_old = form.submit;
    var code = "var ajax = AjaxAnywhere.findInstance(\"" + this.id + "\"); " +
               "if (typeof ajax !='object' || ! ajax.isFormSubmitByAjax() ) " +
               "ajax.findForm().submit_old();" +
               " else " +
               "ajax.submitAJAX();"
    form.submit = new Function(code);

}
/**
* Override this function if you use AjaxAnywhere.substituteFormSubmitFunction() to
* dynamically inform AjaxAnywhere of the method you want to use for the form submission.
*/
AjaxAnywhere.prototype.isFormSubmitByAjax = function () {
    return true;
}

/**
*   If an exception is throws on the server-side during AJAX request, it will be processed
* by this function. The default implementation is alert(stackTrace);
* Override it if you need.
*/
AjaxAnywhere.prototype.handleException = function(type, details) {
    alert(details);
}
/**
*   If an HTTP Error code returned during AJAX request, it will be processed
* by this function. The default implementation is alert(code);
* Override it if you need.
*/
AjaxAnywhere.prototype.handleHttpErrorCode = function(code) {
    alert("AjaxAnywhere default error handler. XMLHttpRequest HTTP Error code:" + code);
}

/**
* Override it if you need.
*/
AjaxAnywhere.prototype.handlePrevousRequestAborted = function() {
    alert("AjaxAnywhere default error handler. INFO: previous AJAX request dropped")
}


/**
*   If the HTML received in responce to AJAX request contains JavaScript that defines new
* functions/variables, they must be propagated to the proper context. Override this method
* to return the Array of function/variable names.
*/
AjaxAnywhere.prototype.getGlobalScriptsDeclarationsList = function(script) {
    return null;
}

/**
* This function should be overridden by AjaxAnywhere user to implement client-side
* determination of zones to reload.
*
* @Returns a comma separated list of zones to reload, or "document.all" to reload
* the whole page. Return null if the form must be submitted in traditional way
*
*
*/
AjaxAnywhere.prototype.getZonesToReaload = function(url) {
    return "";
}

/**
* Override this method to implement a custom action
*/
AjaxAnywhere.prototype.onRequestSent = function () {
};
/**
* Override this method to implement a custom action
*/
AjaxAnywhere.prototype.onBeforeResponseProcessing = function () {
};
/**
* Override this method to implement a custom action
*/
AjaxAnywhere.prototype.onAfterResponseProcessing = function () {
};


// default instance.
ajaxAnywhere = new AjaxAnywhere();
ajaxAnywhere.bindById();