const headings = document.querySelectorAll('h1, h2, h3, h4, h5, h6');
var currentHeading = 0;

document.addEventListener('keydown', function (e) {
	if (e.ctrlKey) return;

	switch (e.code) {
		case 'KeyG':
			currentHeading = (e.shiftKey) ? headings.length - 1 : 0;
			headings[currentHeading].scrollIntoView();
			break;

		case 'KeyJ': case 'KeyL':
			if (typeof presenting != 'undefined' && presenting) showSlide(+1);
			else {
				currentHeading = (headings.length + currentHeading + 1) % headings.length;
				headings[currentHeading].scrollIntoView();
			}
			break;

		case 'KeyK': case 'KeyH':
			if (typeof presenting != 'undefined' && presenting) showSlide(-1);
			else {
				currentHeading = (headings.length + currentHeading - 1) % headings.length;
				headings[currentHeading].scrollIntoView();
			}
			break;

		/* theme-changer.js */

		case 'KeyC':
			themeBtn.click();
			break;

		/* presentation.js */

		// Previous slide
		case 'Backspace': case 'PageUp':
		case 'ArrowLeft': case 'ArrowUp':
			showSlide(-1);
			break;
		// Next slide
		case 'Space': case 'Enter': case 'PageDown':
		
		case 'ArrowRight': case 'ArrowDown':
			showSlide(+1);
			break;
		// Start (toggle) presenting
		case 'KeyP': case 'KeyT':
			presentBtn.click();
			break;
		// Exit presentation
		case 'Escape':
			if (presenting) presentBtn.click();
			break;
		// Go to first slide
		case 'Home':
			showSlide(-slideIndex);
			break;
		// Go to last slide
		case 'End':
			showSlide(-slideIndex -1);
			break;
	}
});