/**
 * Keeps the widget as tall as its content.
 *
 * The framed page posts its height whenever it changes; we accept the message
 * only when it comes from the Piazza in Festa origin and from a window that is
 * one of our own iframes, then set the height. Nothing else leaves or enters
 * the page.
 */
(function () {
	'use strict';

	var cfg = window.pinfestaCfg || {};
	var origin = cfg.origin || '';

	if (!origin) {
		return;
	}

	window.addEventListener('message', function (event) {
		if (event.origin !== origin) {
			return;
		}

		var data = event.data;

		if (!data || data.tipo !== 'piazzainfesta:altezza') {
			return;
		}

		var altezza = parseInt(data.altezza, 10);

		if (!altezza || altezza < 1) {
			return;
		}

		var frames = document.querySelectorAll('iframe.pinfesta-embed');

		for (var i = 0; i < frames.length; i++) {
			if (frames[i].contentWindow === event.source) {
				frames[i].style.height = altezza + 2 + 'px';
			}
		}
	});
})();