// example: registerScriptLink('LoQutus.BreadCrumb', '~sitecollection/siteassets/js/breadcrumb.js', 'Adds a breadcrumb navigation across the site collection');
// example: removeScriptLink('LoQutus.BreadCrumb', null, null, true);

function onError(sender, args) {
    console.log('Error: ' + args.get_message());
}

function registerScriptLink(id, url, description) {

	var ctx = SP.ClientContext.get_current(),
            site = ctx.get_site(),
            userActions = site.get_userCustomActions();

	ctx.load(userActions);
	ctx.executeQueryAsync(
		function () {
			var userActionsEnumerator = userActions.getEnumerator(),
				userAction,
				found;
			while (userActionsEnumerator.moveNext() && !found) {
				userAction = userActionsEnumerator.get_current();
				if (userAction.get_title() === id) {
					found = true;

				}
			}

			if (!found) {
				console.log('Creating new UserCustomAction');
				userAction = userActions.add();
			}

			userAction.set_title(id);
			userAction.set_sequence(2);
			userAction.set_location('ScriptLink');
			userAction.set_scriptSrc(url);
			userAction.set_description(description);
			userAction.update();
			ctx.executeQueryAsync(
				function () {
					console.log('UserCustomAction has been saved');
				},
				onError
			);
		},
		onError
	);
}

function removeScriptLink(id) {
	var ctx = SP.ClientContext.get_current(),
            site = ctx.get_site(),
            userActions = site.get_userCustomActions();

	ctx.load(userActions);
	ctx.executeQueryAsync(
		function () {
			var userActionsEnumerator = userActions.getEnumerator(),
				userAction,
				found;
			while (userActionsEnumerator.moveNext() && !found) {
				userAction = userActionsEnumerator.get_current();
				if (userAction.get_title() === id) {
					found = true;

				}
			}

			if (found) {
				userAction.deleteObject();
				ctx.executeQueryAsync(
					function () {
						console.log('UserCustomAction has been deleted');
					},
					onError
				);
			} else {
				console.log('UserCustomAction not found');
			}
		},
		onError
	);
}