/**
 * http://github.com/Valums-File-Uploader/file-uploader
 *
 * Multiple file upload component with progress-bar, drag-and-drop.
 *
 * Have ideas for improving this JS for the general community?
 * Submit your changes at: https://github.com/Valums-File-Uploader/file-uploader
 *
 * VERSION 2.0 beta
 * Original version 1.0 © 2010 Andrew Valums ( andrew(at)valums.com )
 *
 * Licensed under MIT license, GNU GPL 2 or later, GNU LGPL 2 or later, see license.txt.
 */

//
// Helper functions
//

var qq = qq || {};

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

/**
 * Searches for a given element in the array, returns -1 if it is not present.
 * @param {Number} [from] The index at which to begin the search
 */
qq.indexOf = function(arr, elt, from){
	if (arr.indexOf) return arr.indexOf(elt, from);

	from = from || 0;
	var len = arr.length;

	if (from < 0) from += len;

	for (; from < len; from++){
		if (from in arr && arr[from] === elt){
			return from;
		}
	}
	return -1;
};

qq.getUniqueId = (function(){
	var id = 0;
	return function(){ return id++; };
})();

//
// Browsers and platforms detection

qq.ie       = function(){ return navigator.userAgent.indexOf('MSIE') != -1; }
qq.safari   = function(){ return navigator.vendor != undefined && navigator.vendor.indexOf("Apple") != -1; }
qq.chrome   = function(){ return navigator.vendor != undefined && navigator.vendor.indexOf('Google') != -1; }
qq.firefox  = function(){ return (navigator.userAgent.indexOf('Mozilla') != -1 && navigator.vendor != undefined && navigator.vendor == ''); }
qq.windows  = function(){ return navigator.platform == "Win32"; }

//
// Events

/** Returns the function which detaches attached event */
qq.attach = function(element, type, fn){
	if (element.addEventListener){
		element.addEventListener(type, fn, false);
	} else if (element.attachEvent){
		element.attachEvent('on' + type, fn);
	}
	return function() {
		qq.detach(element, 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()
 *
 * how to use:
 *
 *    `qq.obj2url({a:'b',c:'d'},'http://any.url/upload?otherParam=value');`
 *
 * will result in:
 *
 *    `http://any.url/upload?otherParam=value&a=b&c=d`
 *
 * @param  Object JSON-Object
 * @param  String current querystring-part
 * @return String encoded querystring
 */
qq.obj2url = function(obj, temp, prefixDone){
	var uristrings = [],
			prefix = '&',
			add = function(nextObj, i){
				var nextTemp = temp
						? (/\[\]$/.test(temp)) // prevent double-encoding
						? temp
						: temp+'['+i+']'
						: i;
				if ((nextTemp != 'undefined') && (i != 'undefined')) {
					uristrings.push(
							(typeof nextObj === 'object')
									? qq.obj2url(nextObj, nextTemp, true)
									: (Object.prototype.toString.call(nextObj) === '[object Function]')
									? encodeURIComponent(nextTemp) + '=' + encodeURIComponent(nextObj())
									: encodeURIComponent(nextTemp) + '=' + encodeURIComponent(nextObj)
					);
				}
			};

	if (!prefixDone && temp) {
		prefix = (/\?/.test(temp)) ? (/\?$/.test(temp)) ? '' : '&' : '?';
		uristrings.push(temp);
		uristrings.push(qq.obj2url(obj));
	} else if ((Object.prototype.toString.call(obj) === '[object Array]') && (typeof obj != 'undefined') ) {
		// 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 ((typeof 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(prefix)
			.replace(/^&/, '')
			.replace(/%20/g, '+');
};

//
//
// Uploader Classes
//
//

var qq = qq || {};

/**
 * Creates upload button, validates upload, but doesn't create file list or dd.
 */
qq.FileUploaderBasic = function(o){
	var that = this;
	this._options = {
		// set to true to see the server response
		debug: false,
		action: '/server/upload',
		params: {},
		customHeaders: {},
		button: null,
		multiple: true,
		maxConnections: 3,
		disableCancelForFormUploads: false,
		autoUpload: true,
		// validation
		allowedExtensions: [],
		acceptFiles: null,		// comma separated string of mime-types for browser to display in browse dialog
		sizeLimit: 0,
		minSizeLimit: 0,
		// events
		// return false to cancel submit
		onSubmit: function(id, fileName){},
		onComplete: function(id, fileName, responseJSON){},
		onCancel: function(id, fileName){},
		onUpload: function(id, fileName, xhr){},
		onProgress: function(id, fileName, loaded, total){
			if (loaded === total) {
				var item = that._getItemByFileId(id);
				var cancelLink = that._find(item, 'cancel');
				cancelLink.style.display = 'none';
			}
		},
		onError: function(id, fileName, xhr) {},
		// messages
		messages: {
			typeError: "{file} has an invalid extension. Only {extensions} {isAre} allowed.",
			sizeError: "{file} is too large, maximum file size is {sizeLimit}.",
			minSizeError: "{file} is too small, minimum file size is {minSizeLimit}.",
			emptyError: "{file} is empty, please select files again without it.",
			noFilesError: "No files to upload.",
			onLeave: "The files are being uploaded, if you leave now the upload will be cancelled."
		},
		showMessage: function(message){
			alert(message);
		},
		inputName: 'qqfile',
		extraDropzones : []
	};
	qq.extend(this._options, o);
	qq.extend(this, qq.DisposeSupport);

	// number of files being uploaded
	this._filesInProgress = 0;

	this._storedFiles = [];

	this._handler = this._createUploadHandler();

	if (this._options.button){
		this._button = this._createUploadButton(this._options.button);
	}

	this._preventLeaveInProgress();
};

qq.FileUploaderBasic.prototype = {
	setParams: function(params){
		this._options.params = params;
	},
	getInProgress: function(){
		return this._filesInProgress;
	},
	uploadStoredFiles: function(){
		for (var i = 0; i < this._storedFiles.length; i++) {
			var item = this._getItemByFileId(this._storedFiles[i]);
			this._find(item, 'spinner').style.display = "";
			this._filesInProgress++;
			this._handler.upload(this._storedFiles[i], this._options.params);
		}
	},
	clearStoredFiles: function(){
		this._storedFiles = [];
	},
	_createUploadButton: function(element){
		var self = this;

		var button = new qq.UploadButton({
			element: element,
			multiple: this._options.multiple && qq.UploadHandlerXhr.isSupported(),
			acceptFiles: this._options.acceptFiles,
			onChange: function(input){
				self._onInputChange(input);
			}
		});

		this.addDisposer(function() { button.dispose(); });
		return button;
	},
	_createUploadHandler: function(){
		var self = this,
				handlerClass;

		if(qq.UploadHandlerXhr.isSupported()){
			handlerClass = 'UploadHandlerXhr';
		} else {
			handlerClass = 'UploadHandlerForm';
		}

		var handler = new qq[handlerClass]({
			debug: this._options.debug,
			action: this._options.action,
			encoding: this._options.encoding,
			maxConnections: this._options.maxConnections,
			customHeaders: this._options.customHeaders,
			inputName: this._options.inputName,
			extraDropzones: this._options.extraDropzones,
            demoMode: this._options.demoMode,
			onProgress: function(id, fileName, loaded, total){
				self._onProgress(id, fileName, loaded, total);
				self._options.onProgress(id, fileName, loaded, total);
			},
			onComplete: function(id, fileName, result){
				self._onComplete(id, fileName, result);
				self._options.onComplete(id, fileName, result);
			},
			onCancel: function(id, fileName){
				self._onCancel(id, fileName);
				self._options.onCancel(id, fileName);
			},
			onError: self._options.onError,
			onUpload: function(id, fileName, xhr){
				self._onUpload(id, fileName, xhr);
				self._options.onUpload(id, fileName, xhr);
			}
		});

		return handler;
	},
	_preventLeaveInProgress: function(){
		var self = this;

		this._attach(window, 'beforeunload', function(e){
			if (!self._filesInProgress){return;}

			var e = e || window.event;
			// for ie, ff
			e.returnValue = self._options.messages.onLeave;
			// for webkit
			return self._options.messages.onLeave;
		});
	},
	_onSubmit: function(id, fileName){
		if (this._options.autoUpload) {
			this._filesInProgress++;
		}
	},
	_onProgress: function(id, fileName, loaded, total){
	},
	_onComplete: function(id, fileName, result){
		this._filesInProgress--;
		if (result.error){
			this._options.showMessage(result.error);
		}
	},
	_onCancel: function(id, fileName){
		if (this._options.autoUpload) {
			this._filesInProgress--;
		}
	},
	_onUpload: function(id, fileName, xhr){
	},
	_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){
		if (files.length > 0) {
			for (var i=0; i<files.length; i++){
				if ( !this._validateFile(files[i])){
					return;
				}
			}

			for (var i=0; i<files.length; i++){
				this._uploadFile(files[i]);
			}
		}
		else {
			this._error('noFilesError', "");
		}
	},
	_uploadFile: function(fileContainer){
		var id = this._handler.add(fileContainer);
		var fileName = this._handler.getName(id);

		if (this._options.onSubmit(id, fileName) !== false){
			this._onSubmit(id, fileName);
			if (this._options.autoUpload) {
				this._handler.upload(id, this._options.params);
			}
			else {
				var item = this._getItemByFileId(id);
				this._find(item, 'spinner').style.display = "none";
				this._storedFiles.push(id);
			}
		}
	},
	_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 4 and firefox 11.0a2
			name = (file.fileName !== null && file.fileName !== undefined) ? file.fileName : file.name;
			size = (file.fileSize !== null && file.fileSize !== undefined) ? 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;

		} else if (size && size < this._options.minSizeLimit){
			this._error('minSizeError', name);
			return false;
		}

		return true;
	},
	_error: function(code, fileName){
		var message = this._options.messages[code];
		function r(name, replacement){ message = message.replace(name, replacement); }

		var extensions = this._options.allowedExtensions.join(', ');

		r('{file}', this._formatFileName(fileName));
		r('{extensions}', extensions);
		r('{sizeLimit}', this._formatSize(this._options.sizeLimit));
		r('{minSizeLimit}', this._formatSize(this._options.minSizeLimit));
		r('{isAre}', extensions.indexOf(",") != -1 ? "are" : "is");

		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;
	},
	_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];
	}
};


/**
 * Class that creates upload widget with drag-and-drop and file list
 * @inherits qq.FileUploaderBasic
 */
qq.FileUploader = function(o){
	// call parent constructor
	qq.FileUploaderBasic.apply(this, arguments);

	// additional options
	qq.extend(this._options, {
		element: null,
		// if set, will be used instead of qq-upload-list in template
		listElement: null,
		dragText: 'Drop files here to upload',
		uploadButtonText: 'Upload a file',
		cancelButtonText: 'Cancel',
		failUploadText: 'Upload failed',

		template: '<div class="qq-uploader">' +
				'<div class="qq-upload-drop-area"><span>{dragText}</span></div>' +
				'<div class="qq-upload-button">{uploadButtonText}</div>' +
				'<ul class="qq-upload-list"></ul>' +
				'</div>',

		// template for one item in file list
		fileTemplate: '<li>' +
				'<span class="qq-progress-bar"></span>' +
				'<span class="qq-upload-spinner"></span>' +
				'<span class="qq-upload-finished"></span>' +
				'<span class="qq-upload-file"></span>' +
				'<span class="qq-upload-size"></span>' +
				'<a class="qq-upload-cancel" href="#">{cancelButtonText}</a>' +
				'<span class="qq-upload-failed-text">{failUploadtext}</span>' +
				'</li>',

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

			// added to list item <li> when upload completes
			// used in css to hide progress spinner
			success: 'qq-upload-success',
			fail: 'qq-upload-fail',

			successIcon: null,
			failIcon: null
		}
	});
	// overwrite options with user supplied
	qq.extend(this._options, o);

	// overwrite the upload button text if any
	// same for the Cancel button and Fail message text
	this._options.template     = this._options.template.replace(/\{dragText\}/g, this._options.dragText);
	this._options.template     = this._options.template.replace(/\{uploadButtonText\}/g, this._options.uploadButtonText);
	this._options.fileTemplate = this._options.fileTemplate.replace(/\{cancelButtonText\}/g, this._options.cancelButtonText);
	this._options.fileTemplate = this._options.fileTemplate.replace(/\{failUploadtext\}/g, this._options.failUploadText);

	this._element = this._options.element;
	this._element.innerHTML = this._options.template;
	this._listElement = this._options.listElement || this._find(this._element, 'list');

	this._classes = this._options.classes;

	this._button = this._createUploadButton(this._find(this._element, 'button'));

	this._bindCancelEvent();
	this._setupDragDrop();
};

// inherit from Basic Uploader
qq.extend(qq.FileUploader.prototype, qq.FileUploaderBasic.prototype);

qq.extend(qq.FileUploader.prototype, {
    clearStoredFiles: function() {
        qq.FileUploaderBasic.prototype.clearStoredFiles.apply(this, arguments);
        this._listElement.innerHTML = "";
    },
	addExtraDropzone: function(element){
		this._setupExtraDropzone(element);
	},
	removeExtraDropzone: function(element){
		var dzs = this._options.extraDropzones;
		for(var i in dzs) if (dzs[i] === element) return this._options.extraDropzones.splice(i,1);
	},
	_leaving_document_out: function(e){
		return ((qq.chrome() || (qq.safari() && qq.windows())) && e.clientX == 0 && e.clientY == 0) // null coords for Chrome and Safari Windows
				|| (qq.firefox() && !e.relatedTarget); // null e.relatedTarget for Firefox
	},
	/**
	 * Gets one of the elements listed in this._options.classes
	 **/
	_find: function(parent, type){
		var element = qq.getByClass(parent, this._options.classes[type])[0];
		if (!element){
			throw new Error('element not found ' + type);
		}

		return element;
	},
	_setupExtraDropzone: function(element){
		this._options.extraDropzones.push(element);
		this._setupDropzone(element);
	},
	_setupDropzone: function(dropArea){
		var self = this;

		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);
			}
		});

		this.addDisposer(function() { dz.dispose(); });

		dropArea.style.display = 'none';
	},
	_setupDragDrop: function(){
		var dropArea = this._find(this._element, 'drop');
		var self = this;
		this._options.extraDropzones.push(dropArea);

		var dropzones = this._options.extraDropzones;
		var i;
		for (i=0; i < dropzones.length; i++){
			this._setupDropzone(dropzones[i]);
		}

		// IE <= 9 does not support the File API used for drag+drop uploads
		// Any volunteers to enable & test this for IE10?
		if (!qq.ie()) {
			this._attach(document, 'dragenter', function(e){
				if (qq.hasClass(dropArea, self._classes.dropDisabled)) return;

				dropArea.style.display = 'block';
				for (i=0; i < dropzones.length; i++){ dropzones[i].style.display = 'block'; }

			});
		}
		this._attach(document, 'dragleave', function(e){
			var relatedTarget = document.elementFromPoint(e.clientX, e.clientY);
			// only fire when leaving document out
			if (qq.FileUploader.prototype._leaving_document_out(e)) {
				for (i=0; i < dropzones.length; i++){ dropzones[i].style.display = 'none'; }
			}
		});
		qq.attach(document, 'drop', function(e){
			for (i=0; i < dropzones.length; i++){ dropzones[i].style.display = 'none'; }
			e.preventDefault();
		});
	},
	_onSubmit: function(id, fileName){
		qq.FileUploaderBasic.prototype._onSubmit.apply(this, arguments);
		this._addToList(id, fileName);
	},
	// Update the progress bar & percentage as the file is uploaded
	_onProgress: function(id, fileName, loaded, total){
		qq.FileUploaderBasic.prototype._onProgress.apply(this, arguments);

		var item = this._getItemByFileId(id);
		var size = this._find(item, 'size');
		size.style.display = 'inline';

		var text;
		var percent = Math.round(loaded / total * 100);

		if (loaded != total) {
			// If still uploading, display percentage
			text = percent + '% from ' + this._formatSize(total);
		} else {
			// If complete, just display final size
			text = this._formatSize(total);
		}

		// Update progress bar <span> tag
		this._find(item, 'progressBar').style.width = percent + '%';

		qq.setText(size, text);
	},
	_onComplete: function(id, fileName, result){
		qq.FileUploaderBasic.prototype._onComplete.apply(this, arguments);

		// mark completed
		var item = this._getItemByFileId(id);
		if (!this._options.disableCancelForFormUploads || qq.UploadHandlerXhr.isSupported()) {
			qq.remove(this._find(item, 'cancel'));
		}
		qq.remove(this._find(item, 'spinner'));

		if (result.success){
			qq.addClass(item, this._classes.success);
			if (this._classes.successIcon) {
				this._find(item, 'finished').style.display = "inline-block";
				qq.addClass(item, this._classes.successIcon)
			}
		} else {
			var errorReason = result.reason ? result.reason : "Unknown error";
			qq.addClass(item, this._classes.fail);
			if (this._classes.failIcon) {
				this._find(item, 'finished').style.display = "inline-block";
				qq.addClass(item, this._classes.failIcon)
			}
			item.title = errorReason;
		}
	},
	_addToList: function(id, fileName){
		var item = qq.toElement(this._options.fileTemplate);
		if (this._options.disableCancelForFormUploads && !qq.UploadHandlerXhr.isSupported()) {
			var cancelLink = this._find(item, 'cancel');
			qq.remove(cancelLink);
		}
		item.qqFileId = id;

		var fileElement = this._find(item, 'file');
		qq.setText(fileElement, this._formatFileName(fileName));
		this._find(item, 'size').style.display = 'none';
		if (!this._options.multiple) this._clearList();
		this._listElement.appendChild(item);
	},
	_clearList: function(){
		this._listElement.innerHTML = '';
	},
	_getItemByFileId: function(id){
		var item = this._listElement.firstChild;

		// there can't be txt nodes in dynamically created list
		// and we can  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._listElement;

		this._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);
	qq.extend(this, qq.DisposeSupport);

	this._element = this._options.element;

	this._disableDropOutside();
	this._attachEvents();
};

qq.UploadDropZone.prototype = {
	_dragover_should_be_canceled: function(){
		return qq.safari() || (qq.firefox() && qq.windows());
	},
	_disableDropOutside: function(e){
		// run only once for all instances
		if (!qq.UploadDropZone.dropOutsideDisabled ){

			// for these cases we need to catch onDrop to reset dropArea
			if (this._dragover_should_be_canceled){
				qq.attach(document, 'dragover', function(e){
					e.preventDefault();
				});
			} else {
				qq.attach(document, 'dragover', function(e){
					if (e.dataTransfer){
						e.dataTransfer.dropEffect = 'none';
						e.preventDefault();
					}
				});
			}

			qq.UploadDropZone.dropOutsideDisabled = true;
		}
	},
	_attachEvents: function(){
		var self = this;

		self._attach(self._element, 'dragover', function(e){
			if (!self._isValidFileDrag(e)) return;

			var effect = qq.ie() ? null : 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();
		});

		self._attach(self._element, 'dragenter', function(e){
			if (!self._isValidFileDrag(e)) return;

			self._options.onEnter(e);
		});

		self._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);
		});

		self._attach(self._element, 'drop', function(e){
			if (!self._isValidFileDrag(e)) return;

			e.preventDefault();
			self._options.onDrop(e);
		});
	},
	_isValidFileDrag: function(e){
		// e.dataTransfer currently causing IE errors
		// IE9 does NOT support file API, so drag-and-drop is not possible
		// IE10 should work, but currently has not been tested - any volunteers?
		if (qq.ie()) return false;

		var dt = e.dataTransfer,
		// do not check dt.types.contains in webkit, because it crashes safari 4
				isSafari = qq.safari();

		// dt.effectAllowed is none in Safari 5
		// dt.types.contains check is for firefox
		return dt && dt.effectAllowed != 'none' &&
				(dt.files || (!isSafari && 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,
		acceptFiles: null,
		// 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);
	qq.extend(this, qq.DisposeSupport);

	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");
		}

		if (this._options.acceptFiles) input.setAttribute("accept", this._options.acceptFiles);

		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',
			// 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;
		this._attach(input, 'change', function(){
			self._options.onChange(input);
		});

		this._attach(input, 'mouseover', function(){
			qq.addClass(self._element, self._options.hoverClass);
		});
		this._attach(input, 'mouseout', function(){
			qq.removeClass(self._element, self._options.hoverClass);
		});
		this._attach(input, 'focus', function(){
			qq.addClass(self._element, self._options.focusClass);
		});
		this._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, uploading itself is handled by child classes
 */
qq.UploadHandlerAbstract = function(o){
	// Default options, can be overridden by the user
	this._options = {
		debug: false,
		action: '/upload.php',
		// maximum number of concurrent uploads
		maxConnections: 999,
		onProgress: function(id, fileName, loaded, total){},
		onComplete: function(id, fileName, response){},
		onCancel: function(id, fileName){},
		onUpload: function(id, fileName, xhr){}
	};
	qq.extend(this._options, o);

	this._queue = [];
	// params for files in queue
	this._params = [];
};
qq.UploadHandlerAbstract.prototype = {
	log: function(str){
		if (this._options.debug && window.console) console.log('[uploader] ' + str);
	},
	/**
	 * Adds file or file input to the queue
	 * @returns id
	 **/
	add: function(file){},
	/**
	 * Sends the file identified by id and additional query params to the server
	 */
	upload: function(id, params){
		var len = this._queue.push(id);

		var copy = {};
		qq.extend(copy, params);
		this._params[id] = copy;

		// if too many active uploads, wait...
		if (len <= this._options.maxConnections){
			this._upload(id, this._params[id]);
		}
	},
	/**
	 * Cancels file upload by id
	 */
	cancel: function(id){
		this._cancel(id);
		this._dequeue(id);
	},
	/**
	 * Cancells all uploads
	 */
	cancelAll: function(){
		for (var i=0; i<this._queue.length; i++){
			this._cancel(this._queue[i]);
		}
		this._queue = [];
	},
	/**
	 * Returns name of the file identified by id
	 */
	getName: function(id){},
	/**
	 * Returns size of the file identified by id
	 */
	getSize: function(id){},
	/**
	 * Returns id of files being uploaded or
	 * waiting for their turn
	 */
	getQueue: function(){
		return this._queue;
	},
	/**
	 * Actual upload method
	 */
	_upload: function(id){},
	/**
	 * Actual cancel method
	 */
	_cancel: function(id){},
	/**
	 * Removes element from queue, starts upload of next
	 */
	_dequeue: function(id){
		var i = qq.indexOf(this._queue, id);
		this._queue.splice(i, 1);

		var max = this._options.maxConnections;

		if (this._queue.length >= max && i < max){
			var nextId = this._queue[max-1];
			this._upload(nextId, this._params[nextId]);
		}
	}
};

/**
 * Class for uploading files using form and iframe
 * @inherits qq.UploadHandlerAbstract
 */
qq.UploadHandlerForm = function(o){
	qq.UploadHandlerAbstract.apply(this, arguments);

	this._inputs = {};
	this._detach_load_events = {};
};
// @inherits qq.UploadHandlerAbstract
qq.extend(qq.UploadHandlerForm.prototype, qq.UploadHandlerAbstract.prototype);

qq.extend(qq.UploadHandlerForm.prototype, {
	add: function(fileInput){
		fileInput.setAttribute('name', this._options.inputName);
		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;
	},
	getName: function(id){
		// get input value and remove path to normalize
		return this._inputs[id].value.replace(/.*(\/|\\)/, "");
	},
	_cancel: function(id){
		this._options.onCancel(id, this.getName(id));

		delete this._inputs[id];
		delete this._detach_load_events[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);
		}
	},
	_upload: function(id, params){
		this._options.onUpload(id, this.getName(id), false);
		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.log('iframe loaded');

			var response = self._getIframeContentJSON(iframe);

			self._options.onComplete(id, fileName, response);
			self._dequeue(id);

			delete self._inputs[id];
			// timeout added to fix busy state in FF3.6
			setTimeout(function(){
				self._detach_load_events[id]();
				delete self._detach_load_events[id];
				qq.remove(iframe);
			}, 1);
		});

		form.submit();
		qq.remove(form);

		return id;
	},
	_attachLoadEvent: function(iframe, callback){
		this._detach_load_events[iframe.id] = qq.attach(iframe, 'load', function(){
			// when we remove iframe from dom
			// the request stops, but in IE load
			// event fires
			if (!iframe.parentNode){
				return;
			}

			try {
				// 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;
				}
			}
			catch (error) {
				//IE may throw an "access is denied" error when attempting to access contentDocument on the iframe in some cases
			}

			callback();
		});
	},
	/**
	 * Returns json object received by iframe from server.
	 */
	_getIframeContentJSON: function(iframe){
		//IE may throw an "access is denied" error when attempting to access contentDocument on the iframe in some cases
		try {
			// iframe.contentWindow.document - for IE<7
			var doc = iframe.contentDocument ? iframe.contentDocument: iframe.contentWindow.document,
				response;

			var innerHTML = doc.body.innerHTML;
			this.log("converting iframe's innerHTML to JSON");
			this.log("innerHTML = " + innerHTML);
			//plain text response may be wrapped in <pre> tag
			if (innerHTML.slice(0, 5).toLowerCase() == '<pre>' && innerHTML.slice(-6).toLowerCase() == '</pre>') {
			  innerHTML = doc.body.firstChild.firstChild.nodeValue;
			}
	        response = eval("(" + innerHTML + ")");
		} catch(err){
			response = {success: false};
		}

		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 protocol = this._options.demoMode ? "GET" : "POST"
		var form = qq.toElement('<form method="' + protocol + '" enctype="multipart/form-data"></form>');

		var queryString = qq.obj2url(params, this._options.action);

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

		return form;
	}
});

/**
 * Class for uploading files using xhr
 * @inherits qq.UploadHandlerAbstract
 */
qq.UploadHandlerXhr = function(o){
	qq.UploadHandlerAbstract.apply(this, arguments);

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

	// current loaded size in bytes for each file
	this._loaded = [];
};

// static method
qq.UploadHandlerXhr.isSupported = function(){
	var input = document.createElement('input');
	input.type = 'file';

	return (
			'multiple' in input &&
					typeof File != "undefined" &&
					typeof FormData != "undefined" &&
					typeof (new XMLHttpRequest()).upload != "undefined" );
};

// @inherits qq.UploadHandlerAbstract
qq.extend(qq.UploadHandlerXhr.prototype, qq.UploadHandlerAbstract.prototype)

qq.extend(qq.UploadHandlerXhr.prototype, {
	/**
	 * Adds file to the queue
	 * Returns id to use with upload, cancel
	 **/
	add: function(file){
		if (!(file instanceof File)){
			throw new Error('Passed obj in not a File (in qq.UploadHandlerXhr)');
		}

		return this._files.push(file) - 1;
	},
	getName: function(id){
		var file = this._files[id];
		// fix missing name in Safari 4
		//NOTE: fixed missing name firefox 11.0a2 file.fileName is actually undefined
		return (file.fileName !== null && file.fileName !== undefined) ? file.fileName : file.name;
	},
	getSize: function(id){
		var file = this._files[id];
		return file.fileSize != null ? file.fileSize : file.size;
	},
	/**
	 * Returns uploaded bytes for file identified by id
	 */
	getLoaded: function(id){
		return this._loaded[id] || 0;
	},
	/**
	 * Sends the file identified by id and additional query params to the server
	 * @param {Object} params name-value string pairs
	 */
	_upload: function(id, params){
		this._options.onUpload(id, this.getName(id), true);

		var file = this._files[id],
				name = this.getName(id),
				size = this.getSize(id);

		this._loaded[id] = 0;

		var xhr = this._xhrs[id] = new XMLHttpRequest();
		var self = this;

		xhr.upload.onprogress = function(e){
			if (e.lengthComputable){
				self._loaded[id] = e.loaded;
				self._options.onProgress(id, name, e.loaded, e.total);
			}
		};

		xhr.onreadystatechange = function(){
			if (xhr.readyState == 4){
				self._onComplete(id, xhr);
			}
		};

		// build query string
		params = params || {};
		params[this._options.inputName] = name;
		var queryString = qq.obj2url(params, this._options.action);

        var protocol = this._options.demoMode ? "GET" : "POST";
        xhr.open(protocol, queryString, true);
		xhr.setRequestHeader("X-Requested-With", "XMLHttpRequest");
		xhr.setRequestHeader("X-File-Name", encodeURIComponent(name));
		if (this._options.encoding == 'multipart') {
			var formData = new FormData();
			formData.append(name, file);
			file = formData;
		} else {
			xhr.setRequestHeader("Content-Type", "application/octet-stream");
			//NOTE: return mime type in xhr works on chrome 16.0.9 firefox 11.0a2
			xhr.setRequestHeader("X-Mime-Type",file.type );
		}
		for (key in this._options.customHeaders){
			xhr.setRequestHeader(key, this._options.customHeaders[key]);
		};
		xhr.send(file);
	},
	_onComplete: function(id, xhr){
		// the request was aborted/cancelled
		if (!this._files[id]) return;

		var name = this.getName(id);
		var size = this.getSize(id);

		this._options.onProgress(id, name, size, size);

		if (xhr.status == 200){
			this.log("xhr - server response received");
			this.log("responseText = " + xhr.responseText);

			var response;

			try {
				response = eval("(" + xhr.responseText + ")");
			} catch(err){
				response = {};
			}

			this._options.onComplete(id, name, response);

		} else {
			this._options.onError(id, name, xhr);
			this._options.onComplete(id, name, {});
		}

		this._files[id] = null;
		this._xhrs[id] = null;
		this._dequeue(id);
	},
	_cancel: function(id){
		this._options.onCancel(id, this.getName(id));

		this._files[id] = null;

		if (this._xhrs[id]){
			this._xhrs[id].abort();
			this._xhrs[id] = null;
		}
	}
});

/**
 * A generic module which supports object disposing in dispose() method.
 * */
qq.DisposeSupport = {
	_disposers: [],

	/** Run all registered disposers */
	dispose: function() {
		var disposer;
		while (disposer = this._disposers.shift()) {
			disposer();
		}
	},

	/** Add disposer to the collection */
	addDisposer: function(disposeFunction) {
		this._disposers.push(disposeFunction);
	},

	/** Attach event handler and register de-attacher as a disposer */
	_attach: function() {
		this.addDisposer(qq.attach.apply(this, arguments));
	}
};
