/**
 * @defgroup js_classes_notification
 */
/**
 * @file js/classes/notification/NotificationHelper.js
 *
 * Copyright (c) 2014-2018 Simon Fraser University
 * Copyright (c) 2000-2018 John Willinsky
 * Distributed under the GNU GPL v2. For full terms see the file docs/COPYING.
 *
 * @class NotificationHelper
 * @ingroup js_classes_notification
 *
 * @brief Class that perform notification helper actions.
 */
(function($) {

	/** @type {Object} */
	$.pkp.classes.notification = $.pkp.classes.notification || {};



	/**
	 * @constructor
	 */
	$.pkp.classes.notification.NotificationHelper = function() {
	};


	//
	// Public static helper methods
	//
	/**
	 * Decides which notification will be used: in place or general.
	 * This method finds all notification widgets that are inside of the
	 * handled element of the controller that is handling the current
	 * notify user event (page or modal). We need to make sure that all
	 * notifications will be shown inside the same widget where the notify
	 * user was triggered. Beyond that, we also need to make sure that,
	 * inside some widgets (tabs and accordions, for example) we use the
	 * right notification controller.
	 * To do this, the notification element must follow these rules:
	 *
	 * 1 - the notification element must not have a hidden parent, although
	 * it can be hidden itself.
	 *
	 * 2 - the notification element first widget parent also needs to contain
	 * the element that triggered the notify user event.
	 *
	 * 3 - if the notification element is inside an accordion container, it
	 * will only notify user from events that have the trigger element also
	 * inside the accordion container.
	 *
	 * At the final, if this method find and select more than one
	 * notification element, we get the closest comparing to the element
	 * that triggered the event. If it don't find any visible element, it
	 * bubbles up the event so the site handler can show general
	 * notifications.
	 *
	 * @param {$.pkp.classes.Handler} handler The widget handler that is
	 * handling the notify user event.
	 * @param {HTMLElement|Object} triggerElement The element that triggered the
	 * notify user event.
	 */
	$.pkp.classes.notification.NotificationHelper.redirectNotifyUserEvent =
			function(handler, triggerElement) {

		// Get the selector for a notification element.
		var $notificationSelector = '.pkp_notification',
				$handledElement,
				trivialAlreadyHandled,
				$pageNotificationElements,
				possibleNotificationWidgets,
				i, length,
				notificationsData,
				$accordionContainer,
				$element,
				$elementParents, parentHandler,
				j, parentsLength, $elementParentWidget;


		// Sometimes the notification handler will bubble up
		// the notifyUser event when in place notifications are
		// not visible because of scrolling. When this happens, the
		// trigger element will not be an element, but the notifications
		// data that were shown by the in place but no visible. In those
		// cases, just bubble up again the event until it gets the right
		// handler (the site handler).
		if (triggerElement.content !== undefined) {
			notificationsData = triggerElement;
			handler.getHtmlElement().parent().trigger(
					'notifyUser', [notificationsData]);
			return; // no need to do any other event redirection.
		}

		// Get the html element of the handler.
		$handledElement = handler.getHtmlElement();

		// If the trigger element is inside a grid, let the site
		// handler show TRIVIAL notifications.
		trivialAlreadyHandled = false;
		if (!(handler instanceof $.pkp.controllers.SiteHandler)) {
			if ($(triggerElement).parents('.pkp_controllers_grid').length > 0) {
				$handledElement.parent().trigger('notifyUser');
				trivialAlreadyHandled = true;
			}
		}

		// Find all notification elements inside the handled element.
		$pageNotificationElements = $($notificationSelector, $handledElement);

		// Create a variable to store all possible notification widgets
		// that can notify this event.
		possibleNotificationWidgets = [];

		for (i = 0, length = $pageNotificationElements.length; i < length; i++) {
			$element = $($pageNotificationElements[i]);

			// If it is inside a hidden parent, get next element.
			if ($element.parents(':hidden').length > 0) {
				continue;
			}

			// Find its parent widget.
			// FIXME If we use a class to identify pkp widgets, we can avoid
			// this code duplication from the get handler method in Handler class,
			// unnecessary access to the element data and unnecessary loop.
			$elementParents = $element.parents();
			for (j = 0, parentsLength = $elementParents.length;
					j < parentsLength; j++) {
				parentHandler = $($elementParents[j]).data('pkp.handler');
				if ((parentHandler instanceof $.pkp.classes.Handler)) {
					$elementParentWidget = $($elementParents[j]);
					break;
				}
			}

			// If the element that triggered the event is inside of
			// this widget or is the widget...
			if ($elementParentWidget.has(triggerElement[0]).length ||
					$elementParentWidget[0] === triggerElement[0]) {

				// If it is inside an accordion container, and this accordion container
				// doesn't also contain the element that triggered the event, get other
				// element.
				if ($element.parents('.ui-accordion:first').length > 0) {
					$accordionContainer = $element.parents('.ui-accordion:first');

					if (!$accordionContainer.has(triggerElement[0])) {
						continue;
					}
				}

				// This notification element is able to notify this event.
				possibleNotificationWidgets.push($element);
			}
		}

		// Check if we found a notification element.
		if (possibleNotificationWidgets.length) {

			// Trigger all in place notification widgets found, from the
			// closest to the element that triggered the action to the top.
			for (i = possibleNotificationWidgets.length - 1; i > -1; i--) {
				// Show in place notification to user.
				possibleNotificationWidgets[i].triggerHandler('notifyUser');
			}
		} else {
			if (!trivialAlreadyHandled) {
				// Bubble up the notify user event so the site can handle the
				// general notification.
				handler.getHtmlElement().parent().trigger('notifyUser');
			}
		}
	};


/** @param {jQuery} $ jQuery closure. */
}(jQuery));