class LiteYTEmbed extends HTMLElement {
	connectedCallback() {
		this.videoId = this.getAttribute('videoid');

		let playBtnEl = this.querySelector('.lty-playbtn');
		this.playLabel = (playBtnEl && playBtnEl.textContent.trim()) || this.getAttribute('playlabel') || 'Play';
		if (!this.style.backgroundImage) {
		  this.style.backgroundImage = `url("https://i.ytimg.com/vi/${this.videoId}/hqdefault.jpg")`;
		}
		if (!playBtnEl) {
			playBtnEl = document.createElement('button');
			playBtnEl.type = 'button';
			playBtnEl.classList.add('lty-playbtn');
			this.append(playBtnEl);
		}
		if (!playBtnEl.textContent) {
			const playBtnLabelEl = document.createElement('span');
			playBtnLabelEl.className = 'lyt-visually-hidden';
			playBtnLabelEl.textContent = this.playLabel;
			playBtnEl.append(playBtnLabelEl);
		}
		this.addEventListener('pointerover', LiteYTEmbed.warmConnections, {once: true});
		this.addEventListener('click', this.addIframe);
	}
	static addPrefetch(kind, url, as) {
		const linkEl = document.createElement('link');
		linkEl.rel = kind;
		linkEl.href = url;
		if (as) {
			linkEl.as = as;
		}
		document.head.append(linkEl);
	}
	static warmConnections() {
		if (LiteYTEmbed.preconnected) return;

		LiteYTEmbed.addPrefetch('preconnect', 'https://www.youtube-nocookie.com');
		LiteYTEmbed.addPrefetch('preconnect', 'https://www.google.com');
		LiteYTEmbed.addPrefetch('preconnect', 'https://googleads.g.doubleclick.net');
		LiteYTEmbed.addPrefetch('preconnect', 'https://static.doubleclick.net');

		LiteYTEmbed.preconnected = true;
	}

	addIframe() {
		if (this.classList.contains('lyt-activated')) return;
		this.classList.add('lyt-activated');

		const params = new URLSearchParams(this.getAttribute('params') || []);
		params.append('autoplay', '1');

		const iframeEl = document.createElement('iframe');
		iframeEl.width = 560;
		iframeEl.height = 315;
		iframeEl.sandbox = 'allow-scripts allow-same-origin allow-popups';
		iframeEl.title = this.playLabel;
		iframeEl.allow = 'accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture';
		iframeEl.allowFullscreen = true;
		iframeEl.src = `https://www.youtube-nocookie.com/embed/${encodeURIComponent(this.videoId)}?${params.toString()}`;
		this.append(iframeEl);
		iframeEl.focus();
	}
}
customElements.define('lite-youtube', LiteYTEmbed);