amp.php

<?php
/**
 * AMP functionality
 *
 * @package      EAStarter
 * @author       Bill Erickson
 * @since        1.0.0
 * @license      GPL-2.0+
 **/

/**
 * Is AMP?
 *
 * Conditional tag
 *
 * @return bool Whether AMP.
 */
function ea_is_amp() {
	return function_exists( 'is_amp_endpoint' ) && is_amp_endpoint();
}

/**
 * Generate a class attribute and an AMP class attribute binding.
 *
 * @param string $default Default class value.
 * @param string $active  Value when the state enabled.
 * @param string $state   State variable to toggle based on.
 * @return string HTML attributes.
 */
function ea_amp_class( $default, $active, $state ) {
	$output = '';
	if ( ea_is_amp() ) {
		$output .= sprintf(
			' [class]="%s"',
			esc_attr(
				sprintf(
					'%s ? %s : %s',
					wp_json_encode( $state ),
					wp_json_encode( $default . ' ' . $active ),
					wp_json_encode( $default )
				)
			)
		);
	}
	$output .= sprintf( ' class="%s"', esc_attr( $default ) );

	return $output;
}

/**
 * Add the AMP toggle 'on' attribute.
 *
 * @param string $state State to toggle.
 * @return string The 'on' attribute.
 */
function ea_amp_toggle( $state ) {
	if ( ! ea_is_amp() ) {
		return '';
	}

	return sprintf(
		' on="%s',
		esc_attr(
			sprintf(
				'tap:AMP.setState({ %s: ! %s })',
				esc_js( $state ),
				esc_js( $state )
			)
		)
	);
}

/**
 * AMP Nav Dropdown toggle and class attributes.
 *
 * @param string $theme_location Theme location.
 * @param int    $depth          Depth.
 * @return string The class and on attributes.
 */
function ea_amp_nav_dropdown( $theme_location = '', $depth = 0 ) {

	$key = 'nav';
	if ( ! empty( $theme_location ) ) {
		$key .= ucwords( $theme_location );
	}

	global $submenu_index;
	$submenu_index ++;
	$key .= 'SubmenuExpanded' . $submenu_index;

	if ( 1 < $depth ) {
		$key .= 'Depth' . $depth;
	}

	return ea_amp_toggle( $key ) . ea_amp_class( 'submenu-expand', 'expanded', $key );
}