(function() {
	const observeSelector = '.js-onscreen';
	// TODO - will the form ID ever change?
	const observedNodes = document.querySelectorAll(observeSelector);
	let observedCount = 0;
	let observedTotal = !!observeSelector ? observedNodes.length : 0;

	window.addEventListener('DOMContentLoaded', event => {
		// TODO this selector needs to be robuts
		const enquiryForm = document.querySelector('#wpcf7-f1041-o1 > form');
		const intersectionSupport = !!window.IntersectionObserver;

		function updateObservedCount() {
			observedCount++;
			if (observedCount >= observedTotal) {
				document.body.classList.add('observe-done');
			}
		}

		function onScreenHandler(entries) {
			entries.forEach(entry => {
				if (entry.intersectionRatio > 0) {
					entry.target.classList.add('is-showing', 'has-shown');
				} else {
					entry.target.classList.remove('is-showing');
				}
			});
		}

		if (enquiryForm) {
			enquiryForm.action = '__URL__';
		}

		document.body.classList.add('rwavw-custom');

		observedNodes.forEach(el => {
			if (intersectionSupport) {
				const options = {
					rootMargin: '0px',
					threshold: [0, 1],
				};
				const observer = new IntersectionObserver(onScreenHandler, options);
				observer.observe(el);
				el.classList.add('is-observed');
			}
			updateObservedCount();
		});
	});
})();