/**
 * Build the live regions markup.
 *
 * @param {'polite'|'assertive'} [ariaLive] Value for the 'aria-live' attribute; default: 'polite'.
 *
 * @return The ARIA live region HTML element.
 */
export default function addContainer(
	ariaLive: string = 'polite'
): HTMLDivElement {
	const container = document.createElement( 'div' );
	container.id = `a11y-speak-${ ariaLive }`;
	container.className = 'a11y-speak-region';

	container.setAttribute(
		'style',
		'position:absolute;' +
			'margin:-1px;' +
			'padding:0;' +
			'height:1px;' +
			'width:1px;' +
			'overflow:hidden;' +
			'clip-path:inset(50%);' +
			'border:0;' +
			'word-wrap:normal !important;' +
			'word-break:normal !important;'
	);
	container.setAttribute( 'aria-live', ariaLive );
	container.setAttribute( 'aria-relevant', 'additions text' );
	container.setAttribute( 'aria-atomic', 'true' );

	const { body } = document;
	if ( body ) {
		body.appendChild( container );
	}

	return container;
}