Util.ts

///
/// Copyright OmniFaces
///
/// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
/// the License. You may obtain a copy of the License at
///
///     https://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
/// an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
/// specific language governing permissions and limitations under the License.
///

import { VIEW_STATE_PARAM } from "./OmniFaces";

/**
 * Utility scripts.
 * 
 * @author Bauke Scholtz
 * @since 2.2
 */
export module Util {

	// "Constant" fields ----------------------------------------------------------------------------------------------

	const ERROR_MISSING_FORM = "OmniFaces: Cannot find a JSF form in the document. Please add one.";

	// Public static functions ----------------------------------------------------------------------------------------

	/**
	 * Add given event listener on the given events to the given target.
	 * @param target Target to add event listener to.
	 * @param events Space separated string of event names.
	 * @param listener The event listener.
	 */
	export function addEventListener(target: EventTarget, events: string, listener: Function) {
		handleEventListener(target, "addEventListener", events, listener);
	}

	/**
	 * Remove given event listener on the given events from the given target.
	 * @param target Target to remove event listener from.
	 * @param events Space separated string of event names.
	 * @param listener The event listener.
	 */
	export function removeEventListener(target: EventTarget, events: string, listener: Function) {
		handleEventListener(target, "removeEventListener", events, listener);
	}

	/**
	 * Register the given function as window onload listener function.
	 * @param listener The function to be invoked during window load event.
	 */
	export function addOnloadListener(listener: Function) {
		if (window.jQuery) {
			window.jQuery(listener);
		}
		else if (document.readyState === "complete") {
			setTimeout(listener);
		}
		else {
			addEventListener(window, "load", listener);
		}
	}

	/**
	 * Add submit listener to the document and all synchronous JSF submit handler functions.
	 * @param listener The listener to invoke before the (synchronous) submit.
	 */
	export function addSubmitListener(listener: Function) {
		addEventListener(document, "submit", listener); // Invoke given listener on any (propagated!) submit event (e.g. h:commandLink and p:commandButton ajax=false).

		if (window.mojarra) {
			decorateFacesSubmit(window.mojarra, window.faces ? "cljs" : "jsfcljs", listener); // Decorate Mojarra h:commandLink submit handler to invoke given listener first.
		}

		if (window.myfaces) {
 			decorateFacesSubmit(window.myfaces.oam, "submitForm", listener); // Decorate MyFaces h:commandLink submit handler to invoke given listener first.
		}

		if (window.PrimeFaces) {
 			decorateFacesSubmit(window.PrimeFaces, "addSubmitParam", listener); // Decorate PrimeFaces p:commandLink ajax=false submit handler to invoke given listener first.
		}
	}

	/**
	 * If given function is actually not a function, then try to interpret it as name of a global function.
	 * If it still doesn't resolve to anything, then return a NOOP function.
	 * @param fn Can be function, or string representing function name, or undefined.
	 */
	export function resolveFunction(fn: any) {
		return (typeof fn !== "function") && (fn = window[fn] || function(){}), fn;
	}

	/**
	 * Get the first JSF form containing view state param from the current document.
	 * @return The first JSF form of the current document.
	 */
	export function getFacesForm(): HTMLFormElement | null {
		for (var i = 0; i < document.forms.length; i++) {
			const form = document.forms[i];

			if (form[VIEW_STATE_PARAM]) {
				return form;
			}
		}

		const faces = window.faces || window.jsf;

		if ((!faces || faces.getProjectStage() == "Development") && window.console && console.error) {
			console.error(ERROR_MISSING_FORM);
		}

		return null;
	}

	/**
	 * Update a parameter in given query string in application/x-www-url-encoded format.
	 * @param query The query string.
	 * @param name The name of the parameter to update. If it doesn't exist, then it will be added.
	 * @param value The value of the parameter to update. If it is falsey, then it will be removed.
	 */
	export function updateParameter(query: string, name: string, value: string) {
		const re = new RegExp("(^|[?&#])" + name + "=.*?([&#]|$)", "i");

		if (value) {
			const parameter = name + "=" + encodeURIComponent(value);

			if (!query) {
				query = parameter;
			}
			else if (query.match(re)) {
				query = query.replace(re, "$1" + parameter + "$2");
			}
			else {
				query += "&" + parameter;
			}
		}
		else {
			query = query.replace(re, "$2");
		}

		if (query.charAt(0) == "&") {
			query = query.substring(1);
		}

		return query;
	}

	/**
	 * Load a script.
	 * @param url Required; The URL of the script.
	 * @param crossorigin Optional; The crossorigin of the script. Defaults to "anonymous".
	 * @param integrity Optional; The integrity of the script. Defaults to "".
	 * @param begin Optional; Function to invoke before deferred script is loaded.
	 * @param success Optional; Function to invoke after deferred script is successfully loaded.
	 * @param error Optional; Function to invoke when loading of deferred script failed.
	 * @param complete Optional; Function to invoke after deferred script is loaded, regardless of its success/error outcome.
	 */
	export function loadScript(url: string, crossorigin: string, integrity: string, begin: Function, success: Function, error: Function, complete: Function) {
		const beginFunction = resolveFunction(begin);
		const successFunction = resolveFunction(success);
		const errorFunction = resolveFunction(error);
		const completeFunction = resolveFunction(complete);

		const script = document.createElement("script");
		const head = document.head || document.documentElement;

		script.async = true;
		script.src = url;
		script.setAttribute("crossorigin", crossorigin || "anonymous");
		script.setAttribute("integrity", integrity || "");

		script.onerror = function() {
			errorFunction();
			completeFunction();
		}

		script.onload = function() {
			successFunction();
			completeFunction();
		}

		addOnloadListener(function() {
			beginFunction();
			head.insertBefore(script, null); // IE6 has trouble with appendChild.
		});
	}

	// Private static functions ---------------------------------------------------------------------------------------

	/**
	 * Handle the given target via the given function names to add or remove the given event listener on the given events.
	 * @param target Target to be altered.
	 * @param functionName Standard (W3C) event handler function name to invoke on the given target.
	 * @param events Space separated string of event names.
	 * @param listener The event listener to be added or removed on the given target via given functions.
	 */
	function handleEventListener(target: any, functionName: string, events: string, listener: Function) {
		const eventParts = events.replace(/^\s+|\s+$/g, "").split(/\s+/);

		for (let event of eventParts) {
			if (target[functionName]) {
				target[functionName](event, listener);
			}
		}
	}

	/**
	 * Decorate the JavaScript based submit function of the JSF implementation to invoke the given listener first.
	 * @param {object} facesImpl The JSF implementation script object holding the submit function.
	 * @param {string} functionName The name of the JSF submit function to decorate.
	 * @param {Function} listener The listener to invoke before the JSF submit function.
	 */
	function decorateFacesSubmit(facesImpl: any, functionName: string, listener: Function) {
		const submitFunction = facesImpl[functionName];

		if (submitFunction) {
			facesImpl[functionName] = function() {
				listener();
				return submitFunction.apply(this, arguments);
			};
		}
	}
}