/**
 * EGroupware eTemplate2 - JS Widget base class
 *
 * @license http://opensource.org/licenses/gpl-license.php GPL - GNU General Public License
 * @package etemplate
 * @subpackage api
 * @link https://www.egroupware.org
 * @author Andreas Stöckel
 */

/*egw:uses
	jsapi.egw;
	et2_core_xml;
	et2_core_common;
	et2_core_inheritance;
	et2_core_arrayMgr;
*/

import {ClassWithAttributes} from './et2_core_inheritance';
import {et2_arrayMgr, et2_readonlysArrayMgr} from "./et2_core_arrayMgr";

/**
 * The registry contains all XML tag names and the corresponding widget
 * constructor.
 */
var et2_registry = {};
var et2_attribute_registry = {};


/**
 * Registers the widget class defined by the given constructor, registers all its class attributes, and associates it
 * with the types in the _types array.
 *
 * @param {function} _constructor constructor
 * @param {array} _types widget types _constructor wants to register for
 */
export function et2_register_widget(_constructor, _types)
{
	"use strict";

	et2_attribute_registry[_constructor.name] = ClassWithAttributes.buildAttributes(_constructor);
	// Iterate over all given types and register those
	for (var i = 0; i < _types.length; i++)
	{
		var type = _types[i].toLowerCase();

		// Check whether a widget has already been registered for one of the
		// types.
		if (et2_registry[type])
		{
			egw.debug("warn", "Widget class registered for " + type +
				" will be overwritten.");
		}

		et2_registry[type] = _constructor;
	}
}

/**
 * Creates a widget registered for the given tag-name. If "readonly" is listed
 * inside the attributes, et2_createWidget will try to use the "_ro" type of the
 * widget.
 *
 * @param _name is the name of the widget with which it is registered. If the
 * 	widget is not found, an et2_placeholder will be created.
 * @param _attrs is an associative array with attributes. If not passed, it will
 * 	default to an empty object.
 * @param _parent is the parent to which the element will be attached. If _parent
 * 	is not passed, it will default to null. Then you have to attach the element
 * 	to a parent using the addChild or insertChild method.
 */
export function et2_createWidget(_name : string, _attrs : object, _parent? : any) : et2_widget
{
	"use strict";

	if (typeof _attrs == "undefined")
	{
		_attrs = {};
	}

	if (typeof _attrs != "object")
	{
		_attrs = {};
	}

	if (typeof _parent == "undefined")
	{
		_parent = null;
	}

	// Parse the "readonly" and "type" flag for this element here, as they
	// determine which constructor is used
	var nodeName = _attrs["type"] = _name;
	var readonly = _attrs["readonly"] =
		typeof _attrs["readonly"] == "undefined" ? false : _attrs["readonly"];

	// Get the constructor - if the widget is readonly, use the special "_ro"
	// constructor if it is available
	var constructor = typeof et2_registry[nodeName] == "undefined" ?
		et2_placeholder : et2_registry[nodeName];
	if (readonly && typeof et2_registry[nodeName + "_ro"] != "undefined")
	{
		constructor = et2_registry[nodeName + "_ro"];
	}

	// Do an sanity check for the attributes
	ClassWithAttributes.generateAttributeSet(et2_attribute_registry[constructor.name], _attrs);
	// Create the new widget and return it
	return new constructor(_parent, _attrs);
}

export interface WidgetConfig {
	type?: string;
	readonly?: boolean;
	width?: number;
	[propName: string]: any;
}

/**
 * The et2 widget base class.
 *
 * @augments ClassWithAttributes
 */
export class et2_widget extends ClassWithAttributes
{
	static readonly _attributes: any = {
		"id": {
			"name": "ID",
			"type": "string",
			"description": "Unique identifier of the widget"
		},

		"no_lang": {
			"name": "No translation",
			"type": "boolean",
			"default": false,
			"description": "If true, no translations are made for this widget"
		},

		/**
		 * Ignore the "span" property by default - it is read by the grid and
		 * other widgets.
		 */
		"span": {
			"ignore": true
		},

		/**
		 * Ignore the "type" tag - it is read by the "createElementFromNode"
		 * function and passed as second parameter of the widget constructor
		 */
		"type": {
			"name": "Widget type",
			"type": "string",
			"ignore": true,
			"description": "What kind of widget this is"
		},

		/**
		 * Ignore the readonly tag by default - its also read by the
		 * "createElementFromNode" function.
		 */
		"readonly": {
			"ignore": true
		},

		/**
		 * Widget's attributes
		 */
		attributes: {
			"name": "Widget attributes",
			"type": "any",
			"ignore": true,
			"description": "Object of widget attributes"
		}
	};

	// Set the legacyOptions array to the names of the properties the "options"
	// attribute defines.
	public static readonly legacyOptions: string[] = [];

	private _type: string;
	id: string;
	supportedWidgetClasses : any[];
	options: WidgetConfig;
	readonly: boolean;

	/**
	 * Widget constructor
	 *
	 * To implement the attributes inheritance and overriding each extending class/widget needs to call:
	 *
	 * 	super(_parent, _attrs, ClassWithAttributes.extendAttributes(et2_DOMWidget._attributes, _child || {}));
	 *
	 * @param _parent is the parent object from the XML tree which contains this
	 * 	object. The default constructor always adds the new instance to the
	 * 	children list of the given parent object. _parent may be NULL.
	 * @param _attrs is an associative array of attributes.
	 * @param _child attributes object from the child
	 */
	constructor(_parent?, _attrs? : WidgetConfig, _child? : object)
	{
		super();	// because we in the top of the widget hierarchy
		this.attributes = ClassWithAttributes.extendAttributes(et2_widget._attributes, _child || {});

		// Check whether all attributes are available
		if (typeof _parent == "undefined") {
			_parent = null;
		}

		if (typeof _attrs == "undefined") {
			_attrs = {};
		}

		if (_attrs.attributes) {
			jQuery.extend(_attrs, _attrs.attributes);
		}
		// Initialize all important parameters
		this._mgrs = {};
		this._inst = null;
		this._children = [];
		this._type = _attrs["type"];
		this.id = _attrs["id"];

		// Add this widget to the given parent widget
		if (_parent != null) {
			_parent.addChild(this);
		}

		// The supported widget classes array defines a whitelist for all widget
		// classes or interfaces child widgets have to support.
		this.supportedWidgetClasses = [et2_widget];

		if (_attrs["id"]) {
			// Create a namespace for this object
			if (this._createNamespace()) {
				this.checkCreateNamespace(_attrs);
			}
		}

		if (this.id) {
			//this.id = this.id.replace(/\[/g,'&#x5B;').replace(/]/g,'&#x5D;');
		}

		// Add all attributes hidden in the content arrays to the attributes
		// parameter
		this.transformAttributes(_attrs);

		// Create a local copy of the options object
		this.options = et2_cloneObject(_attrs);
	}

	/**
	 * The destroy function destroys all children of the widget, removes itself
	 * from the parents children list.
	 * In all classes derrived from et2_widget ALWAYS override the destroy
	 * function and remove ALL references to other objects. Also remember to
	 * unbind ANY event this widget created and to remove all DOM-Nodes it
	 * created.
	 */
	destroy()
	{
		// Call the destructor of all children
		for (var i = this._children.length - 1; i >= 0; i--) {
			this._children[i].destroy();
		}

		// Remove this element from the parent, if it exists
		if (typeof this._parent != "undefined" && this._parent !== null) {
			this._parent.removeChild(this);
		}

		// Free the array managers if they belong to this widget
		for (var key in this._mgrs) {
			if (this._mgrs[key] && this._mgrs[key].owner == this) {
				this._mgrs[key].destroy();
			}
		}
	}

	getType() : string
	{
		return this._type;
	}

	setType(_type : string)
	{
		this._type = _type;
	}

	/**
	 * Creates a copy of this widget. The parameters given are passed to the
	 * constructor of the copied object. If the parameters are omitted, _parent
	 * is defaulted to null
	 *
	 * @param {et2_widget} _parent parent to set for clone, default null
	 */
	clone(_parent)
	{
		// Default _parent to null
		if (typeof _parent == "undefined") {
			_parent = null;
		}

		// Create the copy
		var copy = new (<typeof et2_widget>this.constructor)(_parent, this.options);

		// Assign this element to the copy
		copy.assign(this);

		return copy;
	}

	assign(_obj)
	{
		if (typeof _obj._children == "undefined") {
			this.egw().debug("log", "Foo!");
		}

		// Create a clone of all child elements of the given object
		for (var i = 0; i < _obj._children.length; i++) {
			_obj._children[i].clone(this);
		}

		// Copy a reference to the content array manager
		this.setArrayMgrs(_obj.mgrs);
	}

	private _parent: et2_widget;

	/**
	 * Returns the parent widget of this widget
	 */
	getParent() : et2_widget | null
	{
		return this._parent;
	}

	protected _children = [];

	/**
	 * Returns the list of children of this widget.
	 */
	getChildren() : et2_widget[]
	{
		return this._children;
	}

	/**
	 * Returns the base widget
	 */
	getRoot() : et2_widget
	{
		if (this._parent != null) {
			return this._parent.getRoot();
		} else {
			return this;
		}
	}

	/**
	 * Inserts an child at the end of the list.
	 *
	 * @param _node is the node which should be added. It has to be an instance
	 * 	of et2_widget
	 */
	addChild(_node : et2_widget)
	{
		this.insertChild(_node, this._children.length);
	}

	/**
	 * Inserts a child at the given index.
	 *
	 * @param _node is the node which should be added. It has to be an instance
	 * 	of et2_widget
	 * @param _idx is the position at which the element should be added.
	 */
	insertChild(_node : et2_widget, _idx: number)
	{
		// Check whether the node is one of the supported widget classes.
		if (this.isOfSupportedWidgetClass(_node)) {
			// Remove the node from its original parent
			if (_node._parent) {
				_node._parent.removeChild(_node);
			}

			_node._parent = this;
			this._children.splice(_idx, 0, _node);
		} else {
			this.egw().debug("error", "Widget " + _node._type + " is not supported by this widget class", this);
//			throw("Widget is not supported by this widget class!");
		}
	}

	/**
	 * Removes the child but does not destroy it.
	 *
	 * @param {et2_widget} _node child to remove
	 */
	removeChild(_node)
	{
		// Retrieve the child from the child list
		var idx = this._children.indexOf(_node);

		if (idx >= 0) {
			// This element is no longer parent of the child
			_node._parent = null;

			this._children.splice(idx, 1);
		}
	}

	/**
	 * Searches an element by id in the tree, descending into the child levels.
	 *
	 * @param _id is the id you're searching for
	 */
	getWidgetById(_id) : et2_widget | null
	{
		if (this.id == _id) {
			return this;
		}
		if (!this._children) return null;

		for (var i = 0; i < this._children.length; i++) {
			var elem = this._children[i].getWidgetById(_id);

			if (elem != null) {
				return elem;
			}
		}
		if (this.id && _id.indexOf('[') > -1 && this._children.length) {
			var ids = (new et2_arrayMgr()).explodeKey(_id);
			var widget : et2_widget = this;
			for (var i = 0; i < ids.length && widget !== null; i++) {
				widget = widget.getWidgetById(ids[i]);
			}
			return widget;
		}

		return null;
	}

	/**
	 * Function which allows iterating over the complete widget tree.
	 *
	 * @param _callback is the function which should be called for each widget
	 * @param _context is the context in which the function should be executed
	 * @param _type is an optional parameter which specifies a class/interface
	 * 	the elements have to be instanceOf.
	 */
	iterateOver(_callback, _context, _type?)
	{
		if (typeof _type == "undefined") {
			_type = et2_widget;
		}

		if (this.isInTree() && this.instanceOf(_type)) {
			_callback.call(_context, this);
		}

		for (var i = 0; i < this._children.length; i++) {
			this._children[i].iterateOver(_callback, _context, _type);
		}
	}

	/**
	 * Returns true if the widget currently resides in the visible part of the
	 * widget tree. E.g. Templates which have been cloned are not in the visible
	 * part of the widget tree.
	 *
	 * @param _sender
	 * @param {boolean} _vis can be used by widgets overwriting this function - simply
	 * 	write
	 * 		return this._super(inTree);
	 *	when calling this function the _vis parameter does not have to be supplied.
	 */
	isInTree(_sender?, _vis? : boolean)
	{
		if (typeof _vis == "undefined") {
			_vis = true;
		}

		if (this._parent) {
			return _vis && this._parent.isInTree(this);
		}

		return _vis;
	}

	isOfSupportedWidgetClass(_obj)
	{
		for (var i = 0; i < this.supportedWidgetClasses.length; i++) {
			if (_obj instanceof this.supportedWidgetClasses[i]) {
				return true;
			}
		}
		return false;
	}

	/**
	 * The parseXMLAttrs function takes an XML DOM attributes object
	 * and adds the given attributes to the _target associative array. This
	 * function also parses the legacyOptions.
	 *
	 * @param _attrsObj is the XML DOM attributes object
	 * @param {object} _target is the object to which the attributes should be written.
	 * @param {et2_widget} _proto prototype with attributes and legacyOptions attribute
	 */
	parseXMLAttrs(_attrsObj, _target, _proto)
	{
		// Check whether the attributes object is really existing, if not abort
		if (typeof _attrsObj == "undefined") {
			return;
		}

		// Iterate over the given attributes and parse them
		var mgr = this.getArrayMgr("content");
		for (var i = 0; i < _attrsObj.length; i++) {
			var attrName = _attrsObj[i].name;
			var attrValue = _attrsObj[i].value;

			// Special handling for the legacy options
			if (attrName == "options" && _proto.constructor.legacyOptions && _proto.constructor.legacyOptions.length > 0) {
				let legacy = _proto.constructor.legacyOptions || [];
				let attrs = et2_attribute_registry[Object.getPrototypeOf(_proto).constructor.name] || {};
				// Check for modifications on legacy options here.  Normal modifications
				// are handled in widget constructor, but it's too late for legacy options then
				if (_target.id && this.getArrayMgr("modifications").getEntry(_target.id)) {
					var mod : any = this.getArrayMgr("modifications").getEntry(_target.id);
					if (typeof mod.options != "undefined") attrValue = _attrsObj[i].value = mod.options;
				}
				// expand legacyOptions with content
				if (attrValue.charAt(0) == '@' || attrValue.indexOf('$') != -1) {
					attrValue = mgr.expandName(attrValue);
				}

				// Parse the legacy options (as a string, other types not allowed)
				var splitted = et2_csvSplit(attrValue + "");

				for (var j = 0; j < splitted.length && j < legacy.length; j++) {
					// Blank = not set, unless there's more legacy options provided after
					if (splitted[j].trim().length === 0 && legacy.length >= splitted.length) continue;

					// Check to make sure we don't overwrite a current option with a legacy option
					if (typeof _target[legacy[j]] === "undefined") {
						attrValue = splitted[j];

						/**
						If more legacy options than expected, stuff them all in the last legacy option
						Some legacy options take a comma separated list.
						 */
						if (j == legacy.length - 1 && splitted.length > legacy.length) {
							attrValue = splitted.slice(j);
						}

						var attr = et2_attribute_registry[_proto.constructor.name][legacy[j]] || {};

						// If the attribute is marked as boolean, parse the
						// expression as bool expression.
						if (attr.type == "boolean") {
							attrValue = mgr.parseBoolExpression(attrValue);
						} else if (typeof attrValue != "object") {
							attrValue = mgr.expandName(attrValue);
						}
						_target[legacy[j]] = attrValue;
					}
				}
			} else if (attrName == "readonly" && typeof _target[attrName] != "undefined") {
				// do NOT overwrite already evaluated readonly attribute
			} else {
				let attrs = et2_attribute_registry[_proto.constructor.name] || {};
				if (mgr != null && typeof attrs[attrName] != "undefined") {
					var attr = attrs[attrName];

					// If the attribute is marked as boolean, parse the
					// expression as bool expression.
					if (attr.type == "boolean") {
						attrValue = mgr.parseBoolExpression(attrValue);
					} else {
						attrValue = mgr.expandName(attrValue);
					}
				}

				// Set the attribute
				_target[attrName] = attrValue;
			}
		}
	}

	/**
	 * Apply the "modifications" to the element and translate attributes marked
	 * with "translate: true"
	 *
	 * @param {object} _attrs
	 */
	transformAttributes(_attrs)
	{

		// Apply the content of the modifications array
		if (this.id) {
			if (typeof this.id != "string") {
				console.log(this.id);
			}

			if (this.getArrayMgr("modifications")) {
				var data = this.getArrayMgr("modifications").getEntry(this.id);

				// Check for already inside namespace
				if (this._createNamespace() && this.getArrayMgr("modifications").perspectiveData.owner == this) {
					data = this.getArrayMgr("modifications").data;
				}
				if (typeof data === 'object') {
					for (var key in data) {
						_attrs[key] = data[key];
					}
				}
			}
		}

		// Translate the attributes
		for (var key in _attrs) {
			if (_attrs[key] && typeof this.attributes[key] != "undefined") {
				if (this.attributes[key].translate === true ||
					(this.attributes[key].translate === "!no_lang" && !_attrs["no_lang"])) {
					_attrs[key] = this.egw().lang(_attrs[key]);
				}
			}
		}
	}

	/**
	 * Create a et2_widget from an XML node.
	 *
	 * First the type and attributes are read from the node.  Then the readonly & modifications
	 * arrays are checked for changes specific to the loaded data.  Then the appropriate
	 * constructor is called.  After the constructor returns, the widget has a chance to
	 * further initialize itself from the XML node when the widget's loadFromXML() method
	 * is called with the node.
	 *
	 * @param _node XML node to read
	 * @param _name XML node name
	 *
	 * @return et2_widget
	 */
	createElementFromNode(_node, _name?)
	{
		var attributes = {};

		// Parse the "readonly" and "type" flag for this element here, as they
		// determine which constructor is used
		var _nodeName = attributes["type"] = _node.getAttribute("type") ?
			_node.getAttribute("type") : _node.nodeName.toLowerCase();
		var readonly = attributes["readonly"] = this.getArrayMgr("readonlys") ?
			(<any>this.getArrayMgr("readonlys")).isReadOnly(
				_node.getAttribute("id"), _node.getAttribute("readonly"),
				typeof this.readonly !== 'undefined' ? this.readonly : this.options.readonly) : false;

		// Check to see if modifications change type
		var modifications = this.getArrayMgr("modifications");
		if (modifications && _node.getAttribute("id")) {
			var entry : any = modifications.getEntry(_node.getAttribute("id"));
			if (entry == null) {
				// Try again, but skip the fancy stuff
				// TODO: Figure out why the getEntry() call doesn't always work
				var entry = modifications.data[_node.getAttribute("id")];
				if (entry) {
					this.egw().debug("warn", "getEntry(" + _node.getAttribute("id") + ") failed, but the data is there.", modifications, entry);
				} else {
					// Try the root, in case a namespace got missed
					entry = modifications.getRoot().getEntry(_node.getAttribute("id"));
				}
			}
			if (entry && entry.type && typeof entry.type === 'string') {
				_nodeName = attributes["type"] = entry.type;
			}
			entry = null;
		}

		// if _nodeName / type-attribute contains something to expand (eg. type="@${row}[type]"),
		// we need to expand it now as it defines the constructor and by that attributes parsed via parseXMLAttrs!
		if (_nodeName.charAt(0) == '@' || _nodeName.indexOf('$') >= 0) {
			_nodeName = attributes["type"] = this.getArrayMgr('content').expandName(_nodeName);
		}

		// Get the constructor - if the widget is readonly, use the special "_ro"
		// constructor if it is available
		var constructor = typeof et2_registry[_nodeName] == "undefined" ?
			et2_placeholder : et2_registry[_nodeName];
		if (readonly === true && typeof et2_registry[_nodeName + "_ro"] != "undefined") {
			constructor = et2_registry[_nodeName + "_ro"];
		}

		// Parse the attributes from the given XML attributes object
		this.parseXMLAttrs(_node.attributes, attributes, constructor.prototype);

		// Do an sanity check for the attributes
		ClassWithAttributes.generateAttributeSet(et2_attribute_registry[constructor.name], attributes);

		// Creates the new widget, passes this widget as an instance and
		// passes the widgetType. Then it goes on loading the XML for it.
		var widget = new constructor(this, attributes);

		// Load the widget itself from XML
		widget.loadFromXML(_node);

		return widget;
	}

	/**
	 * Loads the widget tree from an XML node
	 *
	 * @param _node xml node
	 */
	loadFromXML(_node)
	{
		// Load the child nodes.
		for (var i = 0; i < _node.childNodes.length; i++) {
			var node = _node.childNodes[i];
			var widgetType = node.nodeName.toLowerCase();

			if (widgetType == "#comment") {
				continue;
			}

			if (widgetType == "#text") {
				if (node.data.replace(/^\s+|\s+$/g, '')) {
					this.loadContent(node.data);
				}
				continue;
			}

			// Create the new element
			this.createElementFromNode(node);
		}
	}

	/**
	 * Called whenever textNodes are loaded from the XML tree
	 *
	 * @param _content
	 */
	loadContent(_content)
	{
	}

	/**
	 * Called when loading the widget (sub-tree) is finished. First when this
	 * function is called, the DOM-Tree is created. loadingFinished is
	 * recursively called for all child elements. Do not directly override this
	 * function but the doLoadingFinished function which is executed before
	 * descending deeper into the DOM-Tree.
	 *
	 * Some widgets (template) do not load immediately because they request
	 * additional resources via AJAX.  They will return a Deferred Promise object.
	 * If you call loadingFinished(promises) after creating such a widget
	 * programmatically, you might need to wait for it to fully complete its
	 * loading before proceeding.  In that case use:
	 * <code>
	 * var promises = [];
	 * widget.loadingFinished(promises);
	 * jQuery.when.apply(null, promises).done( doneCallback );
	 * </code>
	 * @see {@link http://api.jquery.com/category/deferred-object/|jQuery Deferred}
	 *
	 * @param {Promise[]} promises List of promises from widgets that are not done.  Pass an empty array, it will be filled if needed.
	 */
	loadingFinished(promises?)
	{
		// Call all availble setters
		this.initAttributes(this.options);

		// Make sure promises is defined to avoid errors.
		// We'll warn (below) if programmer should have passed it.
		if (typeof promises == "undefined") {
			promises = [];
			var warn_if_deferred = true;
		}

		var loadChildren = function () {
			// Descend recursively into the tree
			for (var i = 0; i < this._children.length; i++) {
				try {
					this._children[i].loadingFinished(promises);
				} catch (e) {
					egw.debug("error", "There was an error with a widget:\nError:%o\nProblem widget:%o", e.valueOf(), this._children[i], e.stack);
				}
			}
		};

		var result = this.doLoadingFinished();
		if (typeof result == "boolean" && result) {
			// Simple widget finishes nicely
			loadChildren.apply(this, arguments);
		} else if (typeof result == "object" && result.done) {
			// Warn if list was not provided
			if (warn_if_deferred) {
				// Might not be a problem, but if you need the widget to be really loaded, it could be
				egw.debug("warn", "Loading was deferred for widget %o, but creator is not checking.  Pass a list to loadingFinished().", this);
			}
			// Widget is waiting.  Add to the list
			promises.push(result);
			// Fihish loading when it's finished
			result.done(jQuery.proxy(loadChildren, this));
		}
	}

	/**
	 * The initAttributes function sets the attributes to their default
	 * values. The attributes are not overwritten, which means, that the
	 * default is only set, if either a setter exists or this[propName] does
	 * not exist yet.
	 *
	 * Overwritten here to compile legacy JS code in attributes of type "js"
	 *
	 * @param {object} _attrs
	 */
	initAttributes(_attrs)
	{
		for (var key in _attrs) {
			if (typeof this.attributes[key] != "undefined" && !this.attributes[key].ignore && !(_attrs[key] == undefined)) {
				var val = _attrs[key];
				// compile string values of attribute type "js" to functions
				if (this.attributes[key].type == 'js' && typeof _attrs[key] == 'string') {
					val = et2_compileLegacyJS(val, this,
						this.instanceOf(et2_inputWidget) ? (<et2_inputWidget><unknown>this).getInputNode() :
							(this.implements(et2_IDOMNode) ? (<et2_IDOMNode><unknown>this).getDOMNode() : null));
				}
				this.setAttribute(key, val, false);
			}
		}
	}

	/**
	 * Does specific post-processing after the widget is loaded.  Most widgets should not
	 * need to do anything here, it should all be done before.
	 *
	 * @return {boolean|Promise} True if the widget is fully loaded, false to avoid procesing children,
	 * or a Promise if loading is not actually finished (eg. waiting for AJAX)
	 *
	 * @see {@link http://api.jquery.com/deferred.promise/|jQuery Promise}
	 */
	doLoadingFinished() : JQueryPromise<any> | boolean
	{
		return true;
	}

	private _egw: IegwAppLocal;

	/**
	 * The egw function returns the instance of the client side api belonging
	 * to this widget tree. The api instance can be set in the "container"
	 * widget using the setApiInstance function.
	 */
	egw() : IegwAppLocal
	{
		// The _egw property is not set
		if (typeof this._egw === 'undefined') {
			if (this._parent != null) {
				return this._parent.egw();
			}

			// Get the window this object belongs to
			var wnd = null;
			if (this.implements(et2_IDOMNode)) {
				var node = (<et2_IDOMNode><unknown>this).getDOMNode();
				if (node && node.ownerDocument) {
					wnd = node.ownerDocument.parentNode || node.ownerDocument.defaultView;
				}
			}

			// If we're the root object, return the phpgwapi API instance
			return egw('phpgwapi', wnd);
		}

		return this._egw;
	}

	/**
	 * Sets the client side api instance. It can be retrieved by the widget tree
	 * by using the "egw()" function.
	 *
	 * @param {IegwAppLocal} _egw egw object to set
	 */
	setApiInstance(_egw : IegwAppLocal)
	{
		this._egw = _egw;
	}

	protected _mgrs = {};

	/**
	 * Sets all array manager objects - this function can be used to set the
	 * root array managers of the container object.
	 *
	 * @param {object} _mgrs
	 */
	setArrayMgrs(_mgrs)
	{
		this._mgrs = et2_cloneObject(_mgrs);
	}

	/**
	 * Returns an associative array containing the top-most array managers.
	 *
	 * @param _mgrs is used internally and should not be supplied.
	 */
	getArrayMgrs(_mgrs? : object)
	{
		if (typeof _mgrs == "undefined") {
			_mgrs = {};
		}

		// Add all managers of this object to the result, if they have not already
		// been set in the result
		for (var key in this._mgrs) {
			if (typeof _mgrs[key] == "undefined") {
				_mgrs[key] = this._mgrs[key];
			}
		}

		// Recursively applies this function to the parent widget
		if (this._parent) {
			this._parent.getArrayMgrs(_mgrs);
		}

		return _mgrs;
	}

	/**
	 * Sets the array manager for the given part
	 *
	 * @param {string} _part which array mgr to set
	 * @param {object} _mgr
	 */
	setArrayMgr(_part : string, _mgr : et2_arrayMgr)
	{
		this._mgrs[_part] = _mgr;
	}

	/**
	 * Returns the array manager object for the given part
	 *
	 * @param {string} managed_array_type name of array mgr to return
	 */
	getArrayMgr(managed_array_type : string) : et2_arrayMgr | null
	{
		if (this._mgrs && typeof this._mgrs[managed_array_type] != "undefined") {
			return this._mgrs[managed_array_type];
		} else if (this._parent) {
			return this._parent.getArrayMgr(managed_array_type);
		}

		return null;
	}

	/**
	 * Checks whether a namespace exists for this element in the content array.
	 * If yes, an own perspective of the content array is created. If not, the
	 * parent content manager is used.
	 *
	 * Constructor attributes are passed in case a child needs to make decisions
	 */
	checkCreateNamespace(_attrs? : any)
	{
		// Get the content manager
		var mgrs = this.getArrayMgrs();

		for (var key in mgrs) {
			var mgr = mgrs[key];

			// Get the original content manager if we have already created a
			// perspective for this node
			if (typeof this._mgrs[key] != "undefined" && mgr.perspectiveData.owner == this) {
				mgr = mgr.parentMgr;
			}

			// Check whether the manager has a namespace for the id of this object
			var entry = mgr.getEntry(this.id);
			if (typeof entry === 'object' && entry !== null || this.id) {
				// The content manager has an own node for this object, so
				// create an own perspective.
				this._mgrs[key] = mgr.openPerspective(this, this.id);
			} else {
				// The current content manager does not have an own namespace for
				// this element, so use the content manager of the parent.
				delete (this._mgrs[key]);
			}
		}
	}

	/**
	 * Widgets that do support a namespace should override and return true.
	 *
	 * Since a private attribute doesn't get instanciated properly before it's needed,
	 * we use a method so we can get what we need while still in the constructor.
	 *
	 * @private
	 */
	protected _createNamespace() : boolean
	{
		return false;
	}

	/**
	 * This is used and therefore it we can not (yet) make it private
	 *
	 * @deprecated use this.getInstanceMgr()
	 */
	_inst = null;

	/**
	 * Sets the instance manager object (of type etemplate2, see etemplate2.js)
	 *
	 * @param {etemplate2} _inst
	 */
	setInstanceManager(_inst)
	{
		this._inst = _inst;
	}

	/**
	 * Returns the instance manager
	 *
	 * @return {etemplate2}
	 */
	getInstanceManager()
	{
		if (this._inst != null) {
			return this._inst;
		} else if (this._parent) {
			return this._parent.getInstanceManager();
		}

		return null;
	}

	/**
	 * Returns the path into the data array.  By default, array manager takes care of
	 * this, but some extensions need to override this
	 */
	getPath()
	{
		var path = this.getArrayMgr("content").getPath();

		// Prevent namespaced widgets with value from going an extra layer deep
		if (this.id && this._createNamespace() && path[path.length - 1] == this.id) path.pop();

		return path;
	}
}