/**
 * http://github.com/valums/file-uploader
 * 
 * Multiple file upload component with progress-bar, drag-and-drop. 
 * © 2010 Andrew Valums andrew(at)valums.com 
 * 
 * Licensed under GNU GPL 2 or later, see license.txt.
 *  
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>. 
 */    
    
var qq = qq || {};

/**
 * Class that creates our multiple file upload widget
 */
qq.FileUploader = function(o){
    this._options = {
        // container element DOM node (ex. $(selector)[0] for jQuery users)
        element: null,
        // url of the server-side upload script, should be on the same domain
        action: '/server/upload',
        // additional data to send, name-value pairs
        params: {},
        // ex. ['jpg', 'jpeg', 'png', 'gif'] or []
        allowedExtensions: [],        
        // size limit in bytes, 0 - no limit
        // this option isn't supported in all browsers
        sizeLimit: 0,
        onSubmit: function(id, fileName){},
        onComplete: function(id, fileName, responseJSON){},

        //
        // UI customizations

        template: '<div class="qq-uploader">' + 
                '<div class="qq-upload-drop-area"><span>Drop photos here to upload</span></div>' +
                '<div class="qq-upload-button">Upload a photo</div>' +
                '<ul class="qq-upload-list"></ul>' + 
             '</div>',

        // template for one item in file list
        fileTemplate: '<li>' +
                '<span class="qq-upload-file"></span>' +
                '<span class="qq-upload-spinner"></span>' +
                '<span class="qq-upload-size"></span>' +
                '<a class="qq-upload-cancel" href="#">Cancel</a>' +
                '<span class="qq-upload-failed-text">Failed</span>' +
            '</li>',

        classes: {
            // used to get elements from templates
            button: 'qq-upload-button',
            drop: 'qq-upload-drop-area',
            dropActive: 'qq-upload-drop-area-active',
            list: 'qq-upload-list',
                        
            file: 'qq-upload-file',
            spinner: 'qq-upload-spinner',
            size: 'qq-upload-size',
            cancel: 'qq-upload-cancel',

            // added to list item when upload completes
            // used in css to hide progress spinner
            success: 'qq-upload-success',
            fail: 'qq-upload-fail'
        },
        messages: {
            //serverError: "Some files were not uploaded, please contact support and/or try again.",
            typeError: "{file} has invalid extension. Only {extensions} are allowed.",
            sizeError: "{file} is too large, maximum file size is {sizeLimit}.",
            emptyError: "{file} is empty, please select files again without it."            
        },
        showMessage: function(message){
            alert(message);
        }
    };

    qq.extend(this._options, o);       
    
    this._element = this._options.element;

    if (this._element.nodeType != 1){
        throw new Error('element param of FileUploader should be dom node');
    }
    
    this._element.innerHTML = this._options.template;
    
    // number of files being uploaded
    this._filesInProgress = 0;
    
    // easier access
    this._classes = this._options.classes;
    
    this._handler = this._createUploadHandler();    
    
    this._bindCancelEvent();
    
    var self = this;
    this._button = new qq.UploadButton({
        element: this._getElement('button'),
        multiple: qq.UploadHandlerXhr.isSupported(),
        onChange: function(input){
            self._onInputChange(input);
        }        
    });        
    
    this._setupDragDrop();
};

qq.FileUploader.prototype = {
    setParams: function(params){
        this._options.params = params;
    },
    /**
     * Returns true if some files are being uploaded, false otherwise
     */
    isUploading: function(){
        return !!this._filesInProgress;
    },  
    /**
     * Gets one of the elements listed in this._options.classes
     * 
     * First optional element is root for search,
     * this._element is default value.
     *
     * Usage
     *  1. this._getElement('button');
     *  2. this._getElement(item, 'file'); 
     **/
    _getElement: function(parent, type){                        
        if (typeof parent == 'string'){
            // parent was not passed
            type = parent;
            parent = this._element;                   
        }
        
        var element = qq.getByClass(parent, this._options.classes[type])[0];
        
        if (!element){
            throw new Error('element not found ' + type);
        }
        
        return element;
    },
    _error: function(code, fileName){
        var message = this._options.messages[code];
        message = message.replace('{file}', this._formatFileName(fileName));
        message = message.replace('{extensions}', this._options.allowedExtensions.join(', '));
        message = message.replace('{sizeLimit}', this._formatSize(this._options.sizeLimit));
        this._options.showMessage(message);                
    },
    _formatFileName: function(name){
        if (name.length > 33){
            name = name.slice(0, 19) + '...' + name.slice(-13);    
        }
        return name;
    },
    _isAllowedExtension: function(fileName){
        var ext = (-1 !== fileName.indexOf('.')) ? fileName.replace(/.*[.]/, '').toLowerCase() : '';
        var allowed = this._options.allowedExtensions;
        
        if (!allowed.length){return true;}        
        
        for (var i=0; i<allowed.length; i++){
            if (allowed[i].toLowerCase() == ext){
                return true;
            }    
        }
        
        return false;
    },
    _setupDragDrop: function(){
        var self = this,
            dropArea = this._getElement('drop');                        

        var dz = new qq.UploadDropZone({
            element: dropArea,
            onEnter: function(e){
                qq.addClass(dropArea, self._classes.dropActive);
                e.stopPropagation();
            },
            onLeave: function(e){
                e.stopPropagation();
            },
            onLeaveNotDescendants: function(e){
                qq.removeClass(dropArea, self._classes.dropActive);  
            },
            onDrop: function(e){
                dropArea.style.display = 'none';
                qq.removeClass(dropArea, self._classes.dropActive);
                self._uploadFileList(e.dataTransfer.files);    
            }
        });
                
        dropArea.style.display = 'none';

        qq.attach(document, 'dragenter', function(e){     
            if (!dz._isValidFileDrag(e)) return; 
            
            dropArea.style.display = 'block';            
        });         
        
        qq.attach(document, 'dragleave', function(e){
            if (!dz._isValidFileDrag(e)) return;
            
            var relatedTarget = document.elementFromPoint(e.clientX, e.clientY);

            // only fire when leaving document out
            if ( ! relatedTarget || relatedTarget.nodeName == "HTML"){               
                dropArea.style.display = 'none';                                            
            }
        });                
    },
    _createUploadHandler: function(){
        var self = this,
            handlerClass;        
        
        if(qq.UploadHandlerXhr.isSupported()){           
            handlerClass = 'UploadHandlerXhr';                        
        } else {
            handlerClass = 'UploadHandlerForm';
        }

        var handler = new qq[handlerClass]({
            action: this._options.action,            
            onProgress: function(id, fileName, loaded, total){
                // is only called for xhr upload
                self._updateProgress(id, loaded, total);                    
            },
            onComplete: function(id, fileName, result){
                self._filesInProgress--;

                // mark completed
                var item = self._getItemByFileId(id);                
                qq.remove(self._getElement(item, 'cancel'));
                qq.remove(self._getElement(item, 'spinner'));
                
                if (result.success){
                    qq.addClass(item, self._classes.success);    
                } else {
                    qq.addClass(item, self._classes.fail);
                    
                    if (result.error){
                       self._options.showMessage(result.error); 
                    }
                }
                    
                self._options.onComplete(id, fileName, result);                                
            }
        });

        return handler;
    },
    _onInputChange: function(input){

        if (this._handler instanceof qq.UploadHandlerXhr){     
            
            this._uploadFileList(input.files);       
            
        } else {
             
            if (this._validateFile(input)){                
                this._uploadFile(input);                                    
            }
                      
        }        
        
        this._button.reset();   
    },  
    _uploadFileList: function(files){
        var valid = true;

        var i = files.length;
        while (i--){         
            if (!this._validateFile(files[i])){
                valid = false;
                break;
            }
        }  
        
        if (valid){                                      
            var i = files.length;
            while (i--){ this._uploadFile(files[i]); }  
        }
    },
    _uploadFile: function(fileContainer){            
        var id = this._handler.add(fileContainer);
        var name = this._handler.getName(id);        
        this._options.onSubmit(id, name);        
        this._addToList(id, name);
        this._handler.upload(id, this._options.params);        
    },      
    _validateFile: function(file){
        var name,size;
 
        if (file.value){
            // it is a file input            
            // get input value and remove path to normalize
            name = file.value.replace(/.*(\/|\\)/, "");
        } else {
            // fix missing properties in Safari
            name = file.fileName != null ? file.fileName : file.name;
            size = file.fileSize != null ? file.fileSize : file.size;
        }
                    
        if (! this._isAllowedExtension(name)){            
            this._error('typeError',name);
            return false;
            
        } else if (size === 0){            
            this._error('emptyError',name);
            return false;
                                                     
        } else if (size && this._options.sizeLimit && size > this._options.sizeLimit){            
            this._error('sizeError',name);
            return false;            
        }
        
        return true;                
    },
    _addToList: function(id, fileName){
        var item = qq.toElement(this._options.fileTemplate);                
        item.qqFileId = id;

        var fileElement = this._getElement(item, 'file');        
        qq.setText(fileElement, this._formatFileName(fileName));
        this._getElement(item, 'size').style.display = 'none';        

        this._getElement('list').appendChild(item);

        this._filesInProgress++;
    },
    _updateProgress: function(id, loaded, total){
        var item = this._getItemByFileId(id);
        var size = this._getElement(item, 'size');
        size.style.display = 'inline';
        
        var text; 
        if (loaded != total){
            text = Math.round(loaded / total * 100) + '% from ' + this._formatSize(total);
        } else {                                   
            text = this._formatSize(total);
        }          
        
        qq.setText(size, text);
    },
    _formatSize: function(bytes){
        var i = -1;                                    
        do {
            bytes = bytes / 1024;
            i++;  
        } while (bytes > 99);
        
        return Math.max(bytes, 0.1).toFixed(1) + ['kB', 'MB', 'GB', 'TB', 'PB', 'EB'][i];          
    },
    _getItemByFileId: function(id){
        var item = this._getElement('list').firstChild;
        
        // there can't be text nodes in our dynamically created list
        // because of that we can safely use nextSibling
        while (item){            
            if (item.qqFileId == id){
                return item;
            }
            
            item = item.nextSibling;
        }          
    },
    /**
     * delegate click event for cancel link 
     **/
    _bindCancelEvent: function(){
        var self = this,
            list = this._getElement('list');            
        
        qq.attach(list, 'click', function(e){
            e = e || window.event;
            var target = e.target || e.srcElement;

            if (qq.hasClass(target, self._classes.cancel)){
                qq.preventDefault(e);

                var item = target.parentNode;
                self._handler.cancel(item.qqFileId);
                qq.remove(item);
            }
        });

    }    
};

qq.UploadDropZone = function(o){
    this._options = {
        element: null,  
        onEnter: function(e){},
        onLeave: function(e){},  
        // is not fired when leaving element by hovering descendants   
        onLeaveNotDescendants: function(e){},   
        onDrop: function(e){}                       
    };
    qq.extend(this._options, o); 
    
    this._element = this._options.element;
    
    this._disableDropOutside();
    this._attachEvents();   
};

qq.UploadDropZone.prototype = {
    _disableDropOutside: function(e){
        // run only once for all instances
        if (!qq.UploadDropZone.dropOutsideDisabled ){

            qq.attach(document, 'dragover', function(e){
                e.dataTransfer.dropEffect = 'none';
                e.preventDefault();            
            });
            
            qq.UploadDropZone.dropOutsideDisabled = true; 
        }        
    },
    _attachEvents: function(){
        var self = this;              
                  
        qq.attach(self._element, 'dragover', function(e){
            if (!self._isValidFileDrag(e)) return;
            
            var effect = e.dataTransfer.effectAllowed;
            if (effect == 'move' || effect == 'linkMove'){
                e.dataTransfer.dropEffect = 'move'; // for FF (only move allowed)    
            } else {                    
                e.dataTransfer.dropEffect = 'copy'; // for Chrome
            }
                                                     
            e.stopPropagation();
            e.preventDefault();                                                                    
        });
        
        qq.attach(self._element, 'dragenter', function(e){
            if (!self._isValidFileDrag(e)) return;
                        
            self._options.onEnter(e);
        });
        
        qq.attach(self._element, 'dragleave', function(e){
            if (!self._isValidFileDrag(e)) return;
            
            self._options.onLeave(e);
            
            var relatedTarget = document.elementFromPoint(e.clientX, e.clientY);                      
            // do not fire when moving a mouse over a descendant
            if (qq.contains(this, relatedTarget)) return;
                        
            self._options.onLeaveNotDescendants(e); 
        });
                
        qq.attach(self._element, 'drop', function(e){
            if (!self._isValidFileDrag(e)) return;
            
            e.preventDefault();
            self._options.onDrop(e);
        });          
    },
    _isValidFileDrag: function(e){
        var dt = e.dataTransfer,
            // do not check dt.types.contains in webkit, because it crashes safari 4            
            isWebkit = navigator.userAgent.indexOf("AppleWebKit") > -1;                        

        // dt.effectAllowed is none in Safari 5
        // dt.types.contains check is for firefox            
        return dt && dt.effectAllowed != 'none' && 
            (dt.files || (!isWebkit && dt.types.contains && dt.types.contains('Files')));
        
    }        
}; 

qq.UploadButton = function(o){
    this._options = {
        element: null,  
        // if set to true adds multiple attribute to file input      
        multiple: false,
        // name attribute of file input
        name: 'file',
        onChange: function(input){},
        hoverClass: 'qq-upload-button-hover',
        focusClass: 'qq-upload-button-focus'                       
    };
    
    qq.extend(this._options, o);
        
    this._element = this._options.element;
    
    // make button suitable container for input
    qq.css(this._element, {
        position: 'relative',
        overflow: 'hidden',
        // Make sure browse button is in the right side
        // in Internet Explorer
        direction: 'ltr'
    });   
    
    this._input = this._createInput();
};

qq.UploadButton.prototype = {
    /* returns file input element */    
    getInput: function(){
        return this._input;
    },
    /* cleans/recreates the file input */
    reset: function(){
        if (this._input.parentNode){
            qq.remove(this._input);    
        }                
        
        qq.removeClass(this._element, this._options.focusClass);
        this._input = this._createInput();
    },    
    _createInput: function(){                
        var input = document.createElement("input");
        
        if (this._options.multiple){
            input.setAttribute("multiple", "multiple");
        }
                
        input.setAttribute("type", "file");
        input.setAttribute("name", this._options.name);
        
        qq.css(input, {
            position: 'absolute',
            // in Opera only 'browse' button
            // is clickable and it is located at
            // the right side of the input
            right: 0,
            top: 0,
            fontFamily: 'Arial',
            // when button is big it becomes visible in IE8 on SOME PCs
            // probably related to http://social.msdn.microsoft.com/forums/en-US/iewebdevelopment/thread/29d0b0e7-4326-4b3e-823c-51420d4cf253
            // 4 persons reported this, the max values that worked for them were 243, 236, 236, 118
            fontSize: '118px',
            margin: 0,
            padding: 0,
            cursor: 'pointer',
            opacity: 0
        });
        
        this._element.appendChild(input);

        var self = this;
        qq.attach(input, 'change', function(){
            self._options.onChange(input);
        });
                
        qq.attach(input, 'mouseover', function(){
            qq.addClass(self._element, self._options.hoverClass);
        });
        qq.attach(input, 'mouseout', function(){
            qq.removeClass(self._element, self._options.hoverClass);
        });
        qq.attach(input, 'focus', function(){
            qq.addClass(self._element, self._options.focusClass);
        });
        qq.attach(input, 'blur', function(){
            qq.removeClass(self._element, self._options.focusClass);
        });

        // IE and Opera, unfortunately have 2 tab stops on file input
        // which is unacceptable in our case, disable keyboard access
        if (window.attachEvent){
            // it is IE or Opera
            input.setAttribute('tabIndex', "-1");
        }

        return input;            
    }        
};

/**
 * Class for uploading files using form and iframe
 */
qq.UploadHandlerForm = function(o){
    this._options = {
        // URL of the server-side upload script,
        // should be on the same domain to get response
        action: '/upload',
        // fires for each file, when iframe finishes loading
        onComplete: function(id, fileName, response){}
    };
    qq.extend(this._options, o);
       
    this._inputs = {};
};
qq.UploadHandlerForm.prototype = {
    /**
     * Adds file input to the queue
     * Returns id to use with upload, cancel
     **/    
    add: function(fileInput){
        fileInput.setAttribute('name', 'qqfile');
        var id = 'qq-upload-handler-iframe' + qq.getUniqueId();       
        
        this._inputs[id] = fileInput;
        
        // remove file input from DOM
        if (fileInput.parentNode){
            qq.remove(fileInput);
        }
                
        return id;
    },
    /**
     * Sends the file identified by id and additional query params to the server
     * @param {Object} params name-value string pairs
     */
    upload: function(id, params){                        
        var input = this._inputs[id];
        
        if (!input){
            throw new Error('file with passed id was not added, or already uploaded or cancelled');
        }                
        
        var fileName = this.getName(id);
                
        var iframe = this._createIframe(id);
        var form = this._createForm(iframe, params);
        form.appendChild(input);

        var self = this;
        this._attachLoadEvent(iframe, function(){            
            self._options.onComplete(id, fileName, self._getIframeContentJSON(iframe));
            
            delete self._inputs[id];
            // timeout added to fix busy state in FF3.6
            setTimeout(function(){
                qq.remove(iframe);
            }, 1);
        });

        form.submit();        
        qq.remove(form);        
        
        return id;
    },
    cancel: function(id){        
        if (id in this._inputs){
            delete this._inputs[id];
        }        

        var iframe = document.getElementById(id);
        if (iframe){
            // to cancel request set src to something else
            // we use src="javascript:false;" because it doesn't
            // trigger ie6 prompt on https
            iframe.setAttribute('src', 'javascript:false;');

            qq.remove(iframe);
        }
    },
    getName: function(id){
        // get input value and remove path to normalize
        return this._inputs[id].value.replace(/.*(\/|\\)/, "");
    },  
    _attachLoadEvent: function(iframe, callback){
        qq.attach(iframe, 'load', function(){
            // when we remove iframe from dom
            // the request stops, but in IE load
            // event fires
            if (!iframe.parentNode){
                return;
            }

            // fixing Opera 10.53
            if (iframe.contentDocument &&
                iframe.contentDocument.body &&
                iframe.contentDocument.body.innerHTML == "false"){
                // In Opera event is fired second time
                // when body.innerHTML changed from false
                // to server response approx. after 1 sec
                // when we upload file with iframe
                return;
            }

            callback();
        });
    },
    /**
     * Returns json object received by iframe from server.
     */
    _getIframeContentJSON: function(iframe){
        // iframe.contentWindow.document - for IE<7
        var doc = iframe.contentDocument ? iframe.contentDocument: iframe.contentWindow.document,
            response;

        try{
            response = eval("(" + doc.body.innerHTML + ")");
        } catch(err){
            response = {};
        }

        return response;
    },
    /**
     * Creates iframe with unique name
     */
    _createIframe: function(id){
        // We can't use following code as the name attribute
        // won't be properly registered in IE6, and new window
        // on form submit will open
        // var iframe = document.createElement('iframe');
        // iframe.setAttribute('name', id);

        var iframe = qq.toElement('<iframe src="javascript:false;" name="' + id + '" />');
        // src="javascript:false;" removes ie6 prompt on https

        iframe.setAttribute('id', id);

        iframe.style.display = 'none';
        document.body.appendChild(iframe);

        return iframe;
    },
    /**
     * Creates form, that will be submitted to iframe
     */
    _createForm: function(iframe, params){
        // We can't use the following code in IE6
        // var form = document.createElement('form');
        // form.setAttribute('method', 'post');
        // form.setAttribute('enctype', 'multipart/form-data');
        // Because in this case file won't be attached to request
        var form = qq.toElement('<form method="post" enctype="multipart/form-data"></form>');

        var queryString = '?' + qq.obj2url(params);

        form.setAttribute('action', this._options.action + queryString);
        form.setAttribute('target', iframe.name);
        form.style.display = 'none';
        document.body.appendChild(form);

        return form;
    }
};

/**
 * Class for uploading files using xhr
 */
qq.UploadHandlerXhr = function(o){
    this._options = {
        // url of the server-side upload script,
        // should be on the same domain
        action: '/upload',
        onProgress: function(id, fileName, loaded, total){},
        onComplete: function(id, fileName, response){}
    };
    qq.extend(this._options, o);

    this._files = [];
    this._xhrs = [];
};

// static method
qq.UploadHandlerXhr.isSupported = function(){
    var input = document.createElement('input');
    input.type = 'file';        
    
    return (
        'multiple' in input &&
        typeof File != "undefined" &&
        typeof (new XMLHttpRequest()).upload != "undefined" );       
};

qq.UploadHandlerXhr.prototype = {
    /**
     * Adds file to the queue
     * Returns id to use with upload, cancel
     **/    
    add: function(file){
        return this._files.push(file) - 1;        
    },
    /**
     * Sends the file identified by id and additional query params to the server
     * @param {Object} params name-value string pairs
     */    
    upload: function(id, params){
        var file = this._files[id],
            name = this.getName(id),
            size = this.getSize(id);
        
        if (!file){
            throw new Error('file with passed id was not added, or already uploaded or cancelled');   
        }
                        
        var xhr = this._xhrs[id] = new XMLHttpRequest();
        var self = this;
                                        
        xhr.upload.onprogress = function(e){
            if (e.lengthComputable){
                self._options.onProgress(id, name, e.loaded, e.total);
            }
        };

        xhr.onreadystatechange = function(){
            // the request was aborted/cancelled
            if (!self._files[id]){
                return;
            }
            
            if (xhr.readyState == 4){
                                
                self._options.onProgress(id, name, size, size);
                
                if (xhr.status == 200){
                    var response;
                    
                    try {
                        response = eval("(" + xhr.responseText + ")");
                    } catch(err){
                        response = {};
                    }
                    
                    self._options.onComplete(id, name, response);
                        
                } else {                   
                    self._options.onComplete(id, name, {});
                }
                
                self._files[id] = null;
                self._xhrs[id] = null;                
            }
        };

        // build query string
        var queryString = '?qqfile=' + encodeURIComponent(name) + '&' + qq.obj2url(params);

        xhr.open("POST", this._options.action + queryString, true);
        xhr.setRequestHeader("X-Requested-With", "XMLHttpRequest");
        xhr.setRequestHeader("X-File-Name", encodeURIComponent(name));
        xhr.setRequestHeader("Content-Type", "application/octet-stream");
        xhr.send(file);

    },
    cancel: function(id){
        this._files[id] = null;
        
        if (this._xhrs[id]){
            this._xhrs[id].abort();
            this._xhrs[id] = null;                                   
        }
    },
    getName: function(id){
        // fix missing name in Safari 4
        var file = this._files[id];
        return file.fileName != null ? file.fileName : file.name;       
    },
    getSize: function(id){
        // fix missing size in Safari 4
        var file = this._files[id];
        return file.fileSize != null ? file.fileSize : file.size;
    }
};

//
// Helper functions
//

var qq = qq || {};

//
// Useful generic functions

/**
 * Adds all missing properties from obj2 to obj1
 */
qq.extend = function(obj1, obj2){
    for (var prop in obj2){
        obj1[prop] = obj2[prop];
    }
};

/**
 * @return {Number} unique id
 */
qq.getUniqueId = (function(){
    var id = 0;
    return function(){
        return id++;
    };
})();

//
// Events

qq.attach = function(element, type, fn){
    if (element.addEventListener){
        element.addEventListener(type, fn, false);
    } else if (element.attachEvent){
        element.attachEvent('on' + type, fn);
    }
};
qq.detach = function(element, type, fn){
    if (element.removeEventListener){
        element.removeEventListener(type, fn, false);
    } else if (element.attachEvent){
        element.detachEvent('on' + type, fn);
    }
};

qq.preventDefault = function(e){
    if (e.preventDefault){
        e.preventDefault();
    } else{
        e.returnValue = false;
    }
};
//
// Node manipulations

/**
 * Insert node a before node b.
 */
qq.insertBefore = function(a, b){
    b.parentNode.insertBefore(a, b);
};
qq.remove = function(element){
    element.parentNode.removeChild(element);
};

qq.contains = function(parent, descendant){       
    // compareposition returns false in this case
    if (parent == descendant) return true;
    
    if (parent.contains){
        return parent.contains(descendant);
    } else {
        return !!(descendant.compareDocumentPosition(parent) & 8);
    }
};

/**
 * Creates and returns element from html string
 * Uses innerHTML to create an element
 */
qq.toElement = (function(){
    var div = document.createElement('div');
    return function(html){
        div.innerHTML = html;
        var element = div.firstChild;
        div.removeChild(element);
        return element;
    };
})();

//
// Node properties and attributes

/**
 * Sets styles for an element.
 * Fixes opacity in IE6-8.
 */
qq.css = function(element, styles){
    if (styles.opacity != null){
        if (typeof element.style.opacity != 'string' && typeof(element.filters) != 'undefined'){
            styles.filter = 'alpha(opacity=' + Math.round(100 * styles.opacity) + ')';
        }
    }
    qq.extend(element.style, styles);
};
qq.hasClass = function(element, name){
    var re = new RegExp('(^| )' + name + '( |$)');
    return re.test(element.className);
};
qq.addClass = function(element, name){
    if (!qq.hasClass(element, name)){
        element.className += ' ' + name;
    }
};
qq.removeClass = function(element, name){
    var re = new RegExp('(^| )' + name + '( |$)');
    element.className = element.className.replace(re, ' ').replace(/^\s+|\s+$/g, "");
};
qq.setText = function(element, text){
    element.innerText = text;
    element.textContent = text;
};

//
// Selecting elements

qq.children = function(element){
    var children = [],
    child = element.firstChild;

    while (child){
        if (child.nodeType == 1){
            children.push(child);
        }
        child = child.nextSibling;
    }

    return children;
};

qq.getByClass = function(element, className){
    if (element.querySelectorAll){
        return element.querySelectorAll('.' + className);
    }

    var result = [];
    var candidates = element.getElementsByTagName("*");
    var len = candidates.length;

    for (var i = 0; i < len; i++){
        if (qq.hasClass(candidates[i], className)){
            result.push(candidates[i]);
        }
    }
    return result;
};

/**
 * obj2url() takes a json-object as argument and generates
 * a querystring. pretty much like jQuery.param()
 *
 * @param  Object JSON-Object
 * @param  String current querystring-part
 * @return String encoded querystring
 */
qq.obj2url = function(obj, temp){   
    var uristrings = [],
        add = function(nextObj, i){
            
            var nextTemp = temp 
              ? (/\[\]$/.test(temp)) // prevent double-encoding
                  ? temp
                  : temp+'['+i+']'
              : i;
              
          uristrings.push(typeof nextObj === 'object' 
              ? qq.obj2url(nextObj, nextTemp)
              : (Object.prototype.toString.call(nextObj) === '[object Function]')
                  ? encodeURIComponent(nextTemp) + '=' + encodeURIComponent(nextObj())
                  : encodeURIComponent(nextTemp) + '=' + encodeURIComponent(nextObj));
        };
        
    if (Object.prototype.toString.call(obj) === '[object Array]'){ 
        // we wont use a for-in-loop on an array (performance)
        for (var i = 0, len = obj.length; i < len; ++i){
            add(obj[i], i);
        }
        
    } else if ((obj !== undefined) && 
               (obj !== null) && 
               (typeof obj === "object")){
                   
        // for anything else but a scalar, we will use for-in-loop
        for (var i in obj){
            add(obj[i], i);
        }
    } else {
        uristrings.push(encodeURIComponent(temp) + '=' + encodeURIComponent(obj));
    }
    
    return uristrings.join('&').replace(/%20/g, '+');
};