<?php

/**

* Class ReaderThemeLoader.

*

* @package AmpProject\AmpWP

*/

namespace AmpProject\AmpWP;

use AmpProject\AmpWP\Infrastructure\Registerable;

use AmpProject\AmpWP\Infrastructure\Service;

use AMP_Options_Manager;

use AMP_Theme_Support;

use AmpProject\AmpWP\Admin\ReaderThemes;

use WP_Theme;

use WP_Customize_Manager;

/**

* Switches to the designated Reader theme when template mode enabled and when requesting an AMP page.

*

* This class does not implement Conditional because other services need to always be able to access this

* service in order to determine whether or a Reader theme is loaded, and if so, what the previously-active theme was.

*

* @package AmpProject\AmpWP

* @since 2.0

* @internal

*/

final class ReaderThemeLoader implements Service, Registerable {

/**

* Paired routing service.

*

* @var PairedRouting

*/

private $paired_routing;

/**

* Reader theme.

*

* @var WP_Theme|null

*/

private $reader_theme;

/**

* Active theme.

*

* Theme which was active before switching to the Reader theme.

*

* @var WP_Theme

*/

private $active_theme;

/**

* Whether the active theme was overridden with the Reader theme.

*

* @var bool

*/

private $theme_overridden = false;

/**

* ReaderThemeLoader constructor.

*

* @param PairedRouting $paired_routing Paired routing service.

*/

public function __construct( PairedRouting $paired_routing ) {

$this->paired_routing = $paired_routing;

}

/**

* Is Reader mode with a Reader theme selected.

*

* @param array $options Options to check. If omitted, the currently-saved options are used.

* @return bool Whether new Reader mode.

*/

public function is_enabled( $options = null ) {

// If the theme was overridden then we know it is enabled. We can't check get_template() at this point because

// it will be identical to $reader_theme.

if ( $this->is_theme_overridden() ) {

return true;

}

if ( null === $options ) {

$options = AMP_Options_Manager::get_options();

}

// If Reader mode is not enabled, then a Reader theme is definitely not going to be served.

if (

! isset( $options[ Option::THEME_SUPPORT ] )

||

AMP_Theme_Support::READER_MODE_SLUG !== $options[ Option::THEME_SUPPORT ]

) {

return false;

}

// If the Legacy Reader mode is active, then a Reader theme is not going to be served.

if ( ! isset( $options[ Option::READER_THEME ] ) ) {

return false;

}

$reader_theme = $options[ Option::READER_THEME ];

if ( ReaderThemes::DEFAULT_READER_THEME === $reader_theme ) {

return false;

}

// If the Reader theme does not exist, then we cannot switch to the reader theme. The Legacy Reader theme will

// be used as a fallback instead.

if ( ! wp_get_theme( $reader_theme )->exists() ) {

return false;

}

// Lastly, if the active theme is not the same as the reader theme, then we can switch to the reader theme.

// Otherwise, the site should instead be in Transitional mode. Note that get_stylesheet() is used as opposed

// to get_template() because the active theme should be allowed to be a child theme of a Reader theme.

return get_stylesheet() !== $reader_theme;

}

/**

* Whether the active theme was overridden with the reader theme.

*

* @return bool Whether theme overridden.

*/

public function is_theme_overridden() {

return $this->theme_overridden;

}

/**

* Register the service with the system.

*

* @return void

*/

public function register() {

// The following needs to run at plugins_loaded because that is when _wp_customize_include runs. Otherwise, the

// most logical action would be setup_theme.

add_action( 'plugins_loaded', [ $this, 'override_theme' ], 9 );

add_filter( 'wp_prepare_themes_for_js', [ $this, 'filter_wp_prepare_themes_to_indicate_reader_theme' ] );

add_action( 'admin_print_footer_scripts-themes.php', [ $this, 'inject_theme_single_template_modifications' ] );

}

/**

* Filter themes for JS to remove action to delete the selected Reader theme and show a notice.

*

* @param array $prepared_themes Array of theme data.

* @return array Themes.

*/

public function filter_wp_prepare_themes_to_indicate_reader_theme( $prepared_themes ) {

if ( ! $this->is_enabled() ) {

return $prepared_themes;

}

$reader_theme_obj = $this->get_reader_theme();

if ( ! $reader_theme_obj instanceof WP_Theme ) {

return $prepared_themes;

}

$reader_theme = $reader_theme_obj->get_stylesheet();

if ( isset( $prepared_themes[ $reader_theme ] ) ) {

// Make sure the AMP Reader theme appears right after the active theme in the list.

$stylesheet = get_stylesheet();

if ( isset( $prepared_themes[ $stylesheet ] ) ) {

$prepared_themes = array_merge(

[

$stylesheet => $prepared_themes[ $stylesheet ],

$reader_theme => $prepared_themes[ $reader_theme ],

],

$prepared_themes

);

}

// Prevent Reader theme from being deleted.

unset( $prepared_themes[ $reader_theme ]['actions']['delete'] );

// Make sure the Customize link goes to AMP.

$prepared_themes[ $reader_theme ]['actions']['customize'] = amp_get_customizer_url();

// Force the theme to be styled as Active.

$prepared_themes[ $reader_theme ]['active'] = true;

// Make sure the hacked Backbone template will use the AMP action links.

$prepared_themes[ $reader_theme ]['ampActiveReaderTheme'] = true;

// Add AMP Reader theme notice.

$prepared_themes[ $reader_theme ]['ampReaderThemeNotice'] = sprintf(

wp_kses(

/* translators: placeholder is link to AMP settings screen */

__( 'This has been <a href="%s">selected</a> as the AMP Reader theme.', 'amp' ),

[

'a' => [ 'href' => true ],

]

),

esc_url( add_query_arg( 'page', AMP_Options_Manager::OPTION_NAME, admin_url( 'admin.php' ) ) . '#reader-themes' )

);

}

return $prepared_themes;

}

/**

* Inject new logic into the Backbone templates for rendering a theme lightbox.

*

* This is admittedly hacky, but WordPress doesn't provide a much better option.

*/

public function inject_theme_single_template_modifications() {

if ( ! $this->is_enabled() ) {

return;

}

$reader_theme = $this->get_reader_theme();

if ( ! $reader_theme instanceof WP_Theme ) {

return;

}

?>

<script>

(function( themeSingleTmpl ) {

if ( ! themeSingleTmpl ) {

return;

}

let text = themeSingleTmpl.text;

text = text.replace(

/(?=<p class="theme-description">)/,

`

<# if ( data.ampReaderThemeNotice ) { #>

<div class="notice notice-info notice-alt inline">

<p>{{{ data.ampReaderThemeNotice }}}</p><?php // phpcs:ignore WordPressVIPMinimum.Security.Mustache.OutputNotation -- Contains link and already sanitized with Kses. ?>

</div>

<# } #>

`

);

// Inject our action links.

text = text.replace(

/(<div class="active-theme">)((?:.|\s)+?)(<\/div>)/,

( match, startDiv, actionLinks, endDiv ) => {

return `

${startDiv}

<# if ( data.ampActiveReaderTheme ) { #>

<a href="{{ data.actions.customize }}" class="button button-primary customize load-customize hide-if-no-customize">

<?php esc_html_e( 'Customize', 'default' ); ?>

</a>

<a href="<?php echo esc_url( add_query_arg( 'page', AMP_Options_Manager::OPTION_NAME, admin_url( 'admin.php' ) ) ); ?>" class="button button-secondary">

<?php esc_html_e( 'AMP Settings', 'amp' ); ?>

</a>

<# } else { #>

${actionLinks}

<# } #>

${endDiv}

`;

}

);

themeSingleTmpl.text = text;

})( document.getElementById( 'tmpl-theme-single' ) );

(function ( themeTmpl, ssrThemeNamePrefixElement ) {

// First update the card that was rendered server-side in wp-admin/themes.php.

if ( ssrThemeNamePrefixElement ) {

ssrThemeNamePrefixElement.textContent = <?php echo wp_json_encode( _x( 'Reader:', 'prefix for theme card in list', 'amp' ) ); ?>;

}

// Then update the Mustache template so that future renders will also have the proper prefix.

if ( themeTmpl ) {

themeTmpl.text = themeTmpl.text.replace(

/(<div class="theme-id-container">)(\s*<# if)/,

function ( match, startDiv ) {

return `

${startDiv}

<# if ( data.ampActiveReaderTheme ) { #>

<h2 class="theme-name" id="{{ data.id }}-name">

<span><?php echo esc_html( _x( 'Reader:', 'prefix for theme card in list', 'amp' ) ); ?></span> {{ data.name }}

</h2>

<# } else if

`;

}

);

}

}) (

document.getElementById( 'tmpl-theme' ),

document.querySelector( <?php echo wp_json_encode( sprintf( '#%s-name > span', $reader_theme->get_stylesheet() ) ); ?> )

);

</script>

<?php

}

/**

* Get reader theme.

*

* If the Reader template mode is enabled

*

* @return WP_Theme|null Theme if selected and no errors.

*/

public function get_reader_theme() {

if ( $this->reader_theme instanceof WP_Theme ) {

return $this->reader_theme;

}

$reader_theme_slug = AMP_Options_Manager::get_option( Option::READER_THEME );

if ( ! $reader_theme_slug ) {

return null;

}

$reader_theme = wp_get_theme( $reader_theme_slug );

if ( $reader_theme->errors() ) {

return null;

}

return $reader_theme;

}

/**

* Get active theme.

*

* The theme that was active before switching to the Reader theme.

*

* @return WP_Theme WP_Theme instance.

*/

public function get_active_theme() {

return $this->active_theme;

}

/**

* Switch theme if in Reader mode, a Reader theme was selected, and the AMP query var is present.

*

* Note that AMP_Theme_Support will redirect to the non-AMP version if AMP is not available for the query.

*

* @see WP_Customize_Manager::start_previewing_theme() which provides for much of the inspiration here.

* @see switch_theme() which ensures the new theme includes the old theme's theme mods.

*/

public function override_theme() {

$this->theme_overridden = false;

if ( ! $this->is_enabled() || ! $this->paired_routing->has_endpoint() ) {

return;

}

$theme = $this->get_reader_theme();

if ( ! $theme instanceof WP_Theme ) {

return;

}

$this->active_theme = wp_get_theme();

$this->reader_theme = $theme;

$this->theme_overridden = true;

$get_template = function () {

return $this->reader_theme->get_template();

};

$get_stylesheet = function () {

return $this->reader_theme->get_stylesheet();

};

add_filter( 'stylesheet', $get_stylesheet );

add_filter( 'template', $get_template );

add_filter(

'pre_option_current_theme',

function () {

return $this->reader_theme->display( 'Name' );

}

);

// @link: https://core.trac.wordpress.org/ticket/20027

add_filter( 'pre_option_stylesheet', $get_stylesheet );

add_filter( 'pre_option_template', $get_template );

// Handle custom theme roots.

add_filter(

'pre_option_stylesheet_root',

function () {

return get_raw_theme_root( $this->reader_theme->get_stylesheet(), true );

}

);

add_filter(

'pre_option_template_root',

function () {

return get_raw_theme_root( $this->reader_theme->get_template(), true );

}

);

$this->disable_widgets();

add_filter( 'customize_previewable_devices', [ $this, 'customize_previewable_devices' ] );

add_action( 'customize_register', [ $this, 'remove_customizer_themes_panel' ], 11 );

}

/**

* Disable widgets.

*/

public function disable_widgets() {

add_filter( 'sidebars_widgets', '__return_empty_array', PHP_INT_MAX );

add_filter(

'customize_loaded_components',

static function ( $components ) {

return array_diff( $components, [ 'widgets' ] );

}

);

remove_theme_support( 'widgets-block-editor' );

}

/**

* Make tablet (smartphone) the default device when opening AMP Customizer.

*

* @param array $devices Devices.

* @return array Devices.

*/

public function customize_previewable_devices( $devices ) {

if ( isset( $devices['tablet'] ) ) {

unset( $devices['desktop']['default'] );

$devices['tablet']['default'] = true;

}

return $devices;

}

/**

* Remove themes panel from AMP Customizer.

*

* @param WP_Customize_Manager $wp_customize Customize manager.

*/

public function remove_customizer_themes_panel( WP_Customize_Manager $wp_customize ) {

$wp_customize->remove_panel( 'themes' );

}

}