Abstract notion of AMP Actions

amp.php

@@ -21,6 +21,9 @@
 require_once( AMP__DIR__ . '/includes/settings/class-amp-customizer-settings.php' );
 require_once( AMP__DIR__ . '/includes/settings/class-amp-customizer-design-settings.php' );
 
+require_once( AMP__DIR__ . '/includes/actions/class-amp-frontend-actions.php' );
+require_once( AMP__DIR__ . '/includes/actions/class-amp-paired-post-actions.php' );
+
 register_activation_hook( __FILE__, 'amp_activate' );
 function amp_activate() {
 	if ( ! did_action( 'amp_init' ) ) {
@@ -111,13 +114,12 @@ function amp_load_classes() {
 }
 
 function amp_add_frontend_actions() {
-	require_once( AMP__DIR__ . '/includes/amp-frontend-actions.php' );
+	AMP_Frontend_Actions::register_hooks();
 }
 
 function amp_add_post_template_actions() {
-	require_once( AMP__DIR__ . '/includes/amp-post-template-actions.php' );
+	AMP_Paired_Post_Actions::register_hooks();
 	require_once( AMP__DIR__ . '/includes/amp-post-template-functions.php' );
-	amp_post_template_init_hooks();
 }
 
 function amp_prepare_render() {

includes/actions/class-amp-actions.php

@@ -0,0 +1,12 @@
+<?php
+
+abstract class AMP_Actions {
+	public static function add_scripts( $template ) {}
+	public static function add_styles( $template ) {}
+	public static function add_fonts( $template ) {}
+	public static function add_boilerplate_css( $template ) {}
+	public static function add_schemaorg_metadata( $template ) {}
+	public static function add_analytics_scripts( $template ) {}
+	public static function add_analytics_data( $template ) {}
+	public static function add_canonical_link( $template ) {}
+}

includes/actions/class-amp-frontend-actions.php

@@ -0,0 +1,19 @@
+<?php
+// Callbacks for adding AMP-related things to the main theme
+
+require_once( AMP__DIR__ . '/includes/actions/class-amp-actions.php' );
+
+class AMP_Frontend_Actions {
+
+	public static function register_hooks() {
+		add_action( 'wp_head', 'AMP_Frontend_Actions::add_canonical' );
+	}
+
+	public static function add_canonical() {
+		if ( false === apply_filters( 'add_canonical_link', true ) ) {
+			return;
+		}
+		$amp_url = amp_get_permalink( get_queried_object_id() );
+		printf( '<link rel="amphtml" href="%s" />', esc_url( $amp_url ) );
+	}
+}

includes/actions/class-amp-paired-post-actions.php

@@ -0,0 +1,106 @@
+<?php
+
+require_once( AMP__DIR__ . '/includes/actions/class-amp-actions.php' );
+
+class AMP_Paired_Post_Actions extends AMP_Actions {
+
+	public static function register_hooks() {
+		add_action( 'amp_post_template_head', 'AMP_Paired_Post_Actions::add_title' );
+		add_action( 'amp_post_template_head', 'AMP_Paired_Post_Actions::add_canonical_link' );
+		add_action( 'amp_post_template_head', 'AMP_Paired_Post_Actions::add_scripts' );
+		add_action( 'amp_post_template_head', 'AMP_Paired_Post_Actions::add_fonts' );
+		add_action( 'amp_post_template_head', 'AMP_Paired_Post_Actions::add_boilerplate_css' );
+		add_action( 'amp_post_template_head', 'AMP_Paired_Post_Actions::add_schemaorg_metadata' );
+		add_action( 'amp_post_template_css', 'AMP_Paired_Post_Actions::add_styles', 99 );
+		add_action( 'amp_post_template_data', 'AMP_Paired_Post_Actions::add_analytics_scripts' );
+		add_action( 'amp_post_template_footer', 'AMP_Paired_Post_Actions::add_analytics_data' );
+	}
+
+	public static function add_title( $amp_template ) {
+		?>
+		<title><?php echo esc_html( $amp_template->get( 'document_title' ) ); ?></title>
+		<?php
+	}
+
+	public static function add_canonical_link( $amp_template ) {
+		?>
+		<link rel="canonical" href="<?php echo esc_url( $amp_template->get( 'canonical_url' ) ); ?>" />
+		<?php
+	}
+
+	public static function add_scripts( $amp_template ) {
+		$scripts = $amp_template->get( 'amp_component_scripts', array() );
+		foreach ( $scripts as $element => $script ) :
+			$custom_type = ($element == 'amp-mustache') ? 'template' : 'element'; ?>
+			<script custom-<?php echo esc_attr( $custom_type ); ?>="<?php echo esc_attr( $element ); ?>" src="<?php echo esc_url( $script ); ?>" async></script>
+		<?php endforeach; ?>
+		<script src="<?php echo esc_url( $amp_template->get( 'amp_runtime_script' ) ); ?>" async></script>
+		<?php
+	}
+
+	public static function add_fonts( $amp_template ) {
+		$font_urls = $amp_template->get( 'font_urls', array() );
+		foreach ( $font_urls as $slug => $url ) : ?>
+			<link rel="stylesheet" href="<?php echo esc_url( $url ); ?>">
+		<?php endforeach;
+	}
+
+	public static function add_boilerplate_css( $amp_template ) {
+		?>
+		<style amp-boilerplate>body{-webkit-animation:-amp-start 8s steps(1,end) 0s 1 normal both;-moz-animation:-amp-start 8s steps(1,end) 0s 1 normal both;-ms-animation:-amp-start 8s steps(1,end) 0s 1 normal both;animation:-amp-start 8s steps(1,end) 0s 1 normal both}@-webkit-keyframes -amp-start{from{visibility:hidden}to{visibility:visible}}@-moz-keyframes -amp-start{from{visibility:hidden}to{visibility:visible}}@-ms-keyframes -amp-start{from{visibility:hidden}to{visibility:visible}}@-o-keyframes -amp-start{from{visibility:hidden}to{visibility:visible}}@keyframes -amp-start{from{visibility:hidden}to{visibility:visible}}</style><noscript><style amp-boilerplate>body{-webkit-animation:none;-moz-animation:none;-ms-animation:none;animation:none}</style></noscript>
+		<?php
+	}
+
+	public static function add_schemaorg_metadata( $amp_template ) {
+		$metadata = $amp_template->get( 'metadata' );
+		if ( empty( $metadata ) ) {
+			return;
+		}
+		?>
+		<script type="application/ld+json"><?php echo wp_json_encode( $metadata ); ?></script>
+		<?php
+	}
+
+	public static function add_styles( $amp_template ) {
+		$styles = $amp_template->get( 'post_amp_styles' );
+		if ( ! empty( $styles ) ) {
+			echo '/* Inline styles */' . PHP_EOL;
+			foreach ( $styles as $selector => $declarations ) {
+				$declarations = implode( ';', $declarations ) . ';';
+				printf( '%1$s{%2$s}', $selector, $declarations );
+			}
+		}
+	}
+
+	public static function add_analytics_scripts( $data ) {
+		if ( ! empty( $data['amp_analytics'] ) ) {
+			$data['amp_component_scripts']['amp-analytics'] = 'https://cdn.ampproject.org/v0/amp-analytics-0.1.js';
+		}
+		return $data;
+	}
+
+	public static  function add_analytics_data( $amp_template ) {
+		$analytics_entries = $amp_template->get( 'amp_analytics' );
+		if ( empty( $analytics_entries ) ) {
+			return;
+		}
+
+		foreach ( $analytics_entries as $id => $analytics_entry ) {
+			if ( ! isset( $analytics_entry['type'], $analytics_entry['attributes'], $analytics_entry['config_data'] ) ) {
+				_doing_it_wrong( __FUNCTION__, sprintf( esc_html__( 'Analytics entry for %s is missing one of the following keys: `type`, `attributes`, or `config_data` (array keys: %s)', 'amp' ), esc_html( $id ), esc_html( implode( ', ', array_keys( $analytics_entry ) ) ) ), '0.3.2' );
+				continue;
+			}
+
+			$script_element = AMP_HTML_Utils::build_tag( 'script', array(
+				'type' => 'application/json',
+			), wp_json_encode( $analytics_entry['config_data'] ) );
+
+			$amp_analytics_attr = array_merge( array(
+				'id' => $id,
+				'type' => $analytics_entry['type'],
+			), $analytics_entry['attributes'] );
+
+			echo AMP_HTML_Utils::build_tag( 'amp-analytics', $amp_analytics_attr, $script_element );
+		}
+	}
+}