Declare post type support based on the admin setting and allow overwrite

amp.php

@@ -17,6 +17,7 @@
 
 require_once AMP__DIR__ . '/back-compat/back-compat.php';
 require_once AMP__DIR__ . '/includes/amp-helper-functions.php';
+require_once AMP__DIR__ . '/includes/amp-post-types-support.php';
 require_once AMP__DIR__ . '/includes/admin/functions.php';
 require_once AMP__DIR__ . '/includes/admin/class-amp-customizer.php';
 require_once AMP__DIR__ . '/includes/settings/class-amp-customizer-settings.php';
@@ -54,14 +55,11 @@ function amp_init() {
 		return;
 	}
 
-	define( 'AMP_QUERY_VAR', apply_filters( 'amp_query_var', 'amp' ) );
-
 	do_action( 'amp_init' );
 
 	load_plugin_textdomain( 'amp', false, plugin_basename( AMP__DIR__ ) . '/languages' );
 
 	add_rewrite_endpoint( AMP_QUERY_VAR, EP_PERMALINK );
-	add_post_type_support( 'post', AMP_QUERY_VAR );
 
 	add_filter( 'request', 'amp_force_query_var_value' );
 	add_action( 'wp', 'amp_maybe_add_actions' );
@@ -74,6 +72,19 @@ function amp_init() {
 	}
 }
 
+/**
+ * Define AMP query var.
+ *
+ * This function must be invoked through the 'after_setup_theme' action to allow
+ * the AMP setting to declare the post types support earlier than plugins/theme.
+ *
+ * @since 0.6
+ */
+function define_query_var() {
+	define( 'AMP_QUERY_VAR', apply_filters( 'amp_query_var', 'amp' ) );
+}
+add_action( 'after_setup_theme', 'define_query_var', 7 );
+
 // Make sure the `amp` query var has an explicit value.
 // Avoids issues when filtering the deprecated `query_string` hook.
 function amp_force_query_var_value( $query_vars ) {

includes/amp-helper-functions.php

@@ -18,11 +18,8 @@ function amp_get_permalink( $post_id ) {
 }
 
 function post_supports_amp( $post ) {
-	// Listen to post types settings.
-	$is_enabled_via_setting = (bool) AMP_Settings_Post_Types::get_instance()->get_settings_value( $post->post_type );
-
-	// Because `add_rewrite_endpoint` doesn't let us target specific post_types.
-	if ( ! post_type_supports( $post->post_type, AMP_QUERY_VAR ) && true !== $is_enabled_via_setting ) {
+	// Because `add_rewrite_endpoint` doesn't let us target specific post_types :(.
+	if ( ! post_type_supports( $post->post_type, AMP_QUERY_VAR ) ) {
 		return false;
 	}
 

includes/amp-post-types-support.php

@@ -0,0 +1,35 @@
+<?php
+/**
+ * AMP Post types support.
+ *
+ * @package AMP
+ * @since 0.6
+ */
+
+/**
+ * Declare core post types support.
+ *
+ * @since 0.6
+ */
+function amp_core_post_types_support() {
+	add_post_type_support( 'post', AMP_QUERY_VAR );
+}
+add_action( 'init', 'amp_core_post_types_support' );
+
+/**
+ * Declare custom post types support.
+ *
+ * This function should only be invoked through the 'after_setup_theme' action to
+ * allow plugins/theme to overwrite the post types support.
+ *
+ * @since 0.6
+ */
+function amp_custom_post_types_support() {
+	// Listen to post types settings.
+	foreach ( AMP_Settings_Post_Types::get_instance()->get_settings() as $post_type => $enabled ) {
+		if ( true === $enabled ) {
+			add_post_type_support( $post_type, AMP_QUERY_VAR );
+		}
+	}
+}
+add_action( 'after_setup_theme', 'amp_custom_post_types_support' );

includes/settings/class-amp-settings-post-types.php

@@ -41,13 +41,18 @@ public function __construct() {
 	public function init() {
 		add_action( 'admin_init', array( $this, 'register_settings' ) );
 		add_action( 'update_option_' . AMP_Settings::SETTINGS_KEY, 'flush_rewrite_rules' );
+		add_action( 'amp_settings_screen', array( $this, 'errors' ) );
 	}
 
 	/**
 	 * Register the current page settings.
 	 */
 	public function register_settings() {
-		register_setting( AMP_Settings::SETTINGS_KEY, AMP_Settings::SETTINGS_KEY );
+		register_setting(
+			AMP_Settings::SETTINGS_KEY,
+			AMP_Settings::SETTINGS_KEY,
+			array( $this, 'validate' )
+		);
 		add_settings_section(
 			$this->section_id,
 			false,
@@ -57,7 +62,7 @@ public function register_settings() {
 		add_settings_field(
 			$this->setting['id'],
 			$this->setting['label'],
-			array( $this, 'render_setting' ),
+			array( $this, 'render' ),
 			AMP_Settings::MENU_SLUG,
 			$this->section_id
 		);
@@ -67,16 +72,24 @@ public function register_settings() {
 	 * Getter for settings value.
 	 *
 	 * @param string $post_type The post type name.
-	 * @return bool Return the setting value.
+	 * @return bool|array Return true if the post type is always on; the setting value otherwise.
 	 */
-	public function get_settings_value( $post_type ) {
-		$settings = get_option( AMP_Settings::SETTINGS_KEY, array() );
+	public function get_settings( $post_type = false ) {
+		$settings = $this->validate( get_option( AMP_Settings::SETTINGS_KEY, array() ) );
+
+		if ( false !== $post_type ) {
+			if ( isset( $settings[ $this->setting['id'] ][ $post_type ] ) ) {
+				return $settings[ $this->setting['id'] ][ $post_type ];
+			}
 
-		if ( isset( $settings[ $this->setting['id'] ][ $post_type ] ) ) {
-			return (bool) $settings[ $this->setting['id'] ][ $post_type ];
+			return false;
 		}
 
-		return false;
+		if ( empty( $settings[ $this->setting['id'] ] ) || ! is_array( $settings[ $this->setting['id'] ] ) ) {
+			return array();
+		}
+
+		return $settings[ $this->setting['id'] ];
 	}
 
 	/**
@@ -102,16 +115,77 @@ public function get_supported_post_types() {
 	 * @param string $post_type The post type name.
 	 * @return object The setting HTML input name attribute.
 	 */
-	public function get_setting_name( $post_type ) {
+	public function get_name_attribute( $post_type ) {
 		$id = $this->setting['id'];
-
 		return AMP_Settings::SETTINGS_KEY . "[{$id}][{$post_type}]";
 	}
 
+	/**
+	 * Check whether the post type should be disabled or not.
+	 *
+	 * Since we can't flag a post type which is not enabled by setting and removed by plugin/theme,
+	 * we can't disable the checkbox but the errors() takes care of this scenario.
+	 *
+	 * @param string $post_type The post type name.
+	 * @return bool True if disabled; false otherwise.
+	 */
+	public function disabled( $post_type ) {
+		$settings = $this->get_settings();
+
+		// Disable if post type support was not added by setting and added by plugin/theme.
+		if ( post_type_supports( $post_type, AMP_QUERY_VAR ) && ! isset( $settings[ $post_type ] ) ) {
+			return true;
+		}
+
+		return false;
+	}
+
+	/**
+	 * Handle errors.
+	 */
+	public function errors() {
+		$settings = $this->get_settings();
+
+		foreach ( $settings as $post_type => $value ) {
+			// Throw error if post type support was added by setting and removed by plugin/theme.
+			if ( true === $value && ! post_type_supports( $post_type, AMP_QUERY_VAR ) ) {
+				$post_type_object = get_post_type_object( $post_type );
+
+				add_settings_error(
+					$post_type,
+					$post_type,
+					sprintf(
+						/* Translators: %s: Post type name. */
+						__( '"%s" could not be activated because support was removed by a plugin or theme', 'amp' ),
+						isset( $post_type_object->label ) ? $post_type_object->label : $post_type
+					)
+				);
+			}
+		}
+	}
+
+	/**
+	 * Validate and sanitize the settings.
+	 *
+	 * @param array $settings The post types settings.
+	 * @return array The post types settings.
+	 */
+	public function validate( $settings ) {
+		if ( ! isset( $settings[ $this->setting['id'] ] ) || ! is_array( $settings[ $this->setting['id'] ] ) ) {
+			return array();
+		}
+
+		foreach ( $settings[ $this->setting['id'] ] as $key => $value ) {
+			$settings[ $this->setting['id'] ][ $key ] = (bool) $value;
+		}
+
+		return $settings;
+	}
+
 	/**
 	 * Setting renderer.
 	 */
-	public function render_setting() {
+	public function render() {
 		require_once AMP__DIR__ . '/templates/admin/settings/fields/checkbox-post-types.php';
 	}
 

includes/settings/class-amp-settings.php

@@ -63,6 +63,12 @@ public function render_screen() {
 			return;
 		}
 
+		/**
+		 * Fires before the AMP settings screen is rendered.
+		 *
+		 * @since 0.6
+		 */
+		do_action( 'amp_settings_screen' );
 		include_once AMP__DIR__ . '/templates/admin/settings/screen.php';
 	}
 

templates/admin/settings/fields/checkbox-post-types.php

@@ -13,7 +13,7 @@
 <fieldset>
 	<?php foreach ( $this->get_supported_post_types() as $post_type ) : ?>
 		<label>
-			<input type="checkbox" value="1" name="<?php echo esc_attr( $this->get_setting_name( $post_type->name ) ); ?>"<?php checked( true, (bool) $this->get_settings_value( $post_type->name ) || post_type_supports( $post_type->name, AMP_QUERY_VAR ) ); ?><?php disabled( true, post_type_supports( $post_type->name, AMP_QUERY_VAR ) ); ?>> <?php echo esc_html( $post_type->label ); ?>
+			<input type="checkbox" value="1" name="<?php echo esc_attr( $this->get_name_attribute( $post_type->name ) ); ?>"<?php checked( true, post_type_supports( $post_type->name, AMP_QUERY_VAR ) ); ?><?php disabled( true, $this->disabled( $post_type->name ) ); ?>> <?php echo esc_html( $post_type->label ); ?>
 		</label>
 		<br>
 	<?php endforeach; ?>

tests/test-amp-post-types-support.php

@@ -0,0 +1,45 @@
+<?php
+/**
+ * Tests for Post Types Support.
+ *
+ * @package AMP
+ * @since 0.6
+ */
+
+/**
+ * Tests for Post Types Support.
+ */
+class Test_AMP_Post_Types_Support extends WP_UnitTestCase {
+
+	/**
+	 * Test amp_core_post_types_support.
+	 *
+	 * @see amp_core_post_types_support()
+	 */
+	public function test_init() {
+		amp_core_post_types_support();
+		$this->assertTrue( post_type_supports( 'post', AMP_QUERY_VAR ) );
+		remove_post_type_support( 'post', AMP_QUERY_VAR );
+	}
+
+	/**
+	 * Test amp_custom_post_types_support.
+	 *
+	 * @see amp_custom_post_types_support()
+	 */
+	public function test_amp_custom_post_types_support() {
+		update_option( AMP_Settings::SETTINGS_KEY, array(
+			'post_types_support' => array(
+				'foo' => true,
+				'bar' => true,
+			),
+		) );
+		amp_custom_post_types_support();
+		$this->assertTrue( post_type_supports( 'foo', AMP_QUERY_VAR ) );
+		$this->assertTrue( post_type_supports( 'bar', AMP_QUERY_VAR ) );
+		delete_option( AMP_Settings::SETTINGS_KEY );
+		remove_post_type_support( 'foo', AMP_QUERY_VAR );
+		remove_post_type_support( 'bar', AMP_QUERY_VAR );
+	}
+
+}