<?php

/**

 * Customize API: WP_Customize_Selective_Refresh class

 *

 * @package WordPress

 * @subpackage Customize

 * @since 4.5.0

 */

/**

 * Core Customizer class for implementing selective refresh.

 *

 * @since 4.5.0

 */

final class WP_Customize_Selective_Refresh {

	/**

	 * Query var used in requests to render partials.

	 *

	 * @since 4.5.0

	 */

	const RENDER_QUERY_VAR = 'wp_customize_render_partials';

	/**

	 * Customize manager.

	 *

	 * @since 4.5.0

	 * @var WP_Customize_Manager

	 */

	public $manager;

	/**

	 * Registered instances of WP_Customize_Partial.

	 *

	 * @since 4.5.0

	 * @var WP_Customize_Partial[]

	 */

	protected $partials = array();

	/**

	 * Log of errors triggered when partials are rendered.

	 *

	 * @since 4.5.0

	 * @var array

	 */

	protected $triggered_errors = array();

	/**

	 * Keep track of the current partial being rendered.

	 *

	 * @since 4.5.0

	 * @var string

	 */

	protected $current_partial_id;

	/**

	 * Plugin bootstrap for Partial Refresh functionality.

	 *

	 * @since 4.5.0

	 *

	 * @param WP_Customize_Manager $manager Manager instance.

	 */

	public function __construct( WP_Customize_Manager $manager ) {

		$this->manager = $manager;

		require_once( ABSPATH . WPINC . '/customize/class-wp-customize-partial.php' );

		add_action( 'customize_preview_init', array( $this, 'init_preview' ) );

	}

	/**

	 * Retrieves the registered partials.

	 *

	 * @since 4.5.0

	 *

	 * @return array Partials.

	 */

	public function partials() {

		return $this->partials;

	}

	/**

	 * Adds a partial.

	 *

	 * @since 4.5.0

	 *

	 * @param WP_Customize_Partial|string $id   Customize Partial object, or Panel ID.

	 * @param array                       $args {

	 *  Optional. Array of properties for the new Partials object. Default empty array.

	 *

	 *  @type string   $type                  Type of the partial to be created.

	 *  @type string   $selector              The jQuery selector to find the container element for the partial, that is, a partial's placement.

	 *  @type array    $settings              IDs for settings tied to the partial.

	 *  @type string   $primary_setting       The ID for the setting that this partial is primarily responsible for

	 *                                        rendering. If not supplied, it will default to the ID of the first setting.

	 *  @type string   $capability            Capability required to edit this partial.

	 *                                        Normally this is empty and the capability is derived from the capabilities

	 *                                        of the associated `$settings`.

	 *  @type callable $render_callback       Render callback.

	 *                                        Callback is called with one argument, the instance of WP_Customize_Partial.

	 *                                        The callback can either echo the partial or return the partial as a string,

	 *                                        or return false if error.

	 *  @type bool     $container_inclusive   Whether the container element is included in the partial, or if only

	 *                                        the contents are rendered.

	 *  @type bool     $fallback_refresh      Whether to refresh the entire preview in case a partial cannot be refreshed.

	 *                                        A partial render is considered a failure if the render_callback returns

	 *                                        false.

	 * }

	 * @return WP_Customize_Partial             The instance of the panel that was added.

	 */

	public function add_partial( $id, $args = array() ) {

		if ( $id instanceof WP_Customize_Partial ) {

			$partial = $id;

		} else {

			$class = 'WP_Customize_Partial';

			/** This filter is documented in wp-includes/customize/class-wp-customize-selective-refresh.php */

			$args = apply_filters( 'customize_dynamic_partial_args', $args, $id );

			/** This filter is documented in wp-includes/customize/class-wp-customize-selective-refresh.php */

			$class = apply_filters( 'customize_dynamic_partial_class', $class, $id, $args );

			$partial = new $class( $this, $id, $args );

		}

		$this->partials[ $partial->id ] = $partial;

		return $partial;

	}

	/**

	 * Retrieves a partial.

	 *

	 * @since 4.5.0

	 *

	 * @param string $id Customize Partial ID.

	 * @return WP_Customize_Partial|null The partial, if set. Otherwise null.

	 */

	public function get_partial( $id ) {

		if ( isset( $this->partials[ $id ] ) ) {

			return $this->partials[ $id ];

		} else {

			return null;

		}

	}

	/**

	 * Removes a partial.

	 *

	 * @since 4.5.0

	 *

	 * @param string $id Customize Partial ID.

	 */

	public function remove_partial( $id ) {

		unset( $this->partials[ $id ] );

	}

	/**

	 * Initializes the Customizer preview.

	 *

	 * @since 4.5.0

	 */

	public function init_preview() {

		add_action( 'template_redirect', array( $this, 'handle_render_partials_request' ) );

		add_action( 'wp_enqueue_scripts', array( $this, 'enqueue_preview_scripts' ) );

	}

	/**

	 * Enqueues preview scripts.

	 *

	 * @since 4.5.0

	 */

	public function enqueue_preview_scripts() {

		wp_enqueue_script( 'customize-selective-refresh' );

		add_action( 'wp_footer', array( $this, 'export_preview_data' ), 1000 );

	}

	/**

	 * Exports data in preview after it has finished rendering so that partials can be added at runtime.

	 *

	 * @since 4.5.0

	 */

	public function export_preview_data() {

		$partials = array();

		foreach ( $this->partials() as $partial ) {

			if ( $partial->check_capabilities() ) {

				$partials[ $partial->id ] = $partial->json();

			}

		}

		$switched_locale = switch_to_locale( get_user_locale() );

			'shiftClickToEdit' => __( 'Shift-click to edit this element.' ),

			/* translators: %s: document.write() */

			'badDocumentWrite' => sprintf( __( '%s is forbidden' ), 'document.write()' ),

		);

		if ( $switched_locale ) {

			restore_previous_locale();

		}

		$exports = array(

			'partials'       => $partials,

			'renderQueryVar' => self::RENDER_QUERY_VAR,

			'l10n'           => $l10n,

		);

		// Export data to JS.

		echo sprintf( '<script>var _customizePartialRefreshExports = %s;</script>', wp_json_encode( $exports ) );

	}

	/**

	 * Registers dynamically-created partials.

	 *

	 * @since 4.5.0

	 *

	 * @see WP_Customize_Manager::add_dynamic_settings()

	 *

	 */

	public function add_dynamic_partials( $partial_ids ) {

		$new_partials = array();

		foreach ( $partial_ids as $partial_id ) {

			// Skip partials already created.

			$partial = $this->get_partial( $partial_id );

			if ( $partial ) {

				continue;

			}

			$partial_class = 'WP_Customize_Partial';

			/**

			 * Filters a dynamic partial's constructor arguments.

			 *

			 * For a dynamic partial to be registered, this filter must be employed

			 * to override the default false value with an array of args to pass to

			 * the WP_Customize_Partial constructor.

			 *

			 * @since 4.5.0

			 *

			 * @param false|array $partial_args The arguments to the WP_Customize_Partial constructor.

			 * @param string      $partial_id   ID for dynamic partial.

			 */

			$partial_args = apply_filters( 'customize_dynamic_partial_args', $partial_args, $partial_id );

			if ( false === $partial_args ) {

				continue;

			}

			/**

			 * Filters the class used to construct partials.

			 *

			 * Allow non-statically created partials to be constructed with custom WP_Customize_Partial subclass.

			 *

			 * @since 4.5.0

			 *

			 * @param string $partial_class WP_Customize_Partial or a subclass.

			 * @param string $partial_id    ID for dynamic partial.

			 * @param array  $partial_args  The arguments to the WP_Customize_Partial constructor.

			 */

			$partial_class = apply_filters( 'customize_dynamic_partial_class', $partial_class, $partial_id, $partial_args );

			$partial = new $partial_class( $this, $partial_id, $partial_args );

			$this->add_partial( $partial );

			$new_partials[] = $partial;

		}

		return $new_partials;

	}

	/**

	 * Checks whether the request is for rendering partials.

	 *

	 * Note that this will not consider whether the request is authorized or valid,

	 * just that essentially the route is a match.

	 *

	 * @since 4.5.0

	 *

	 * @return bool Whether the request is for rendering partials.

	 */

	public function is_render_partials_request() {

		return ! empty( $_POST[ self::RENDER_QUERY_VAR ] );

	}

	/**

	 * Handles PHP errors triggered during rendering the partials.

	 *

	 * These errors will be relayed back to the client in the Ajax response.

	 *

	 * @since 4.5.0

	 *

	 * @param int    $errno   Error number.

	 * @param string $errstr  Error string.

	 * @param string $errfile Error file.

	 * @param string $errline Error line.

	 * @return true Always true.

	 */

	public function handle_error( $errno, $errstr, $errfile = null, $errline = null ) {

		$this->triggered_errors[] = array(

			'partial'      => $this->current_partial_id,

			'error_number' => $errno,

			'error_string' => $errstr,

			'error_file'   => $errfile,

			'error_line'   => $errline,

		);

		return true;

	}

	/**

	 * Handles the Ajax request to return the rendered partials for the requested placements.

	 *

	 * @since 4.5.0

	 */

	public function handle_render_partials_request() {

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

			return;

		}

		/*

		 * Note that is_customize_preview() returning true will entail that the

		 * user passed the 'customize' capability check and the nonce check, since

		 * WP_Customize_Manager::setup_theme() is where the previewing flag is set.

		 */

		if ( ! is_customize_preview() ) {

			wp_send_json_error( 'expected_customize_preview', 403 );

		} elseif ( ! isset( $_POST['partials'] ) ) {

			wp_send_json_error( 'missing_partials', 400 );

		}

		// Ensure that doing selective refresh on 404 template doesn't result in fallback rendering behavior (full refreshes).

		status_header( 200 );

		$partials = json_decode( wp_unslash( $_POST['partials'] ), true );

		if ( ! is_array( $partials ) ) {

			wp_send_json_error( 'malformed_partials' );

		}

		$this->add_dynamic_partials( array_keys( $partials ) );

		/**

		 * Fires immediately before partials are rendered.

		 *

		 * Plugins may do things like call wp_enqueue_scripts() and gather a list of the scripts

		 * and styles which may get enqueued in the response.

		 *

		 * @since 4.5.0

		 *

		 * @param WP_Customize_Selective_Refresh $this     Selective refresh component.

		 * @param array                          $partials Placements' context data for the partials rendered in the request.

		 *                                                 The array is keyed by partial ID, with each item being an array of

		 *                                                 the placements' context data.

		 */

		do_action( 'customize_render_partials_before', $this, $partials );

		set_error_handler( array( $this, 'handle_error' ), error_reporting() );

		$contents = array();

		foreach ( $partials as $partial_id => $container_contexts ) {

			$this->current_partial_id = $partial_id;

			if ( ! is_array( $container_contexts ) ) {

				wp_send_json_error( 'malformed_container_contexts' );

			}

			$partial = $this->get_partial( $partial_id );

			if ( ! $partial || ! $partial->check_capabilities() ) {

				$contents[ $partial_id ] = null;

				continue;

			}

			$contents[ $partial_id ] = array();

			// @todo The array should include not only the contents, but also whether the container is included?

			if ( empty( $container_contexts ) ) {

				// Since there are no container contexts, render just once.

				$contents[ $partial_id ][] = $partial->render( null );

			} else {

				foreach ( $container_contexts as $container_context ) {

					$contents[ $partial_id ][] = $partial->render( $container_context );

				}

			}

		}

		$this->current_partial_id = null;

		restore_error_handler();

		/**

		 * Fires immediately after partials are rendered.

		 *

		 * Plugins may do things like call wp_footer() to scrape scripts output and return them

		 * via the {@see 'customize_render_partials_response'} filter.

		 *

		 * @since 4.5.0

		 *

		 * @param WP_Customize_Selective_Refresh $this     Selective refresh component.

		 * @param array                          $partials Placements' context data for the partials rendered in the request.

		 *                                                 The array is keyed by partial ID, with each item being an array of

		 *                                                 the placements' context data.

		 */

		do_action( 'customize_render_partials_after', $this, $partials );

		$response = array(

			'contents' => $contents,

		);

		if ( defined( 'WP_DEBUG_DISPLAY' ) && WP_DEBUG_DISPLAY ) {

			$response['errors'] = $this->triggered_errors;

		}

		$response['setting_validities'] = $exported_setting_validities;

		/**

		 * Filters the response from rendering the partials.

		 *

		 * Plugins may use this filter to inject `$scripts` and `$styles`, which are dependencies

		 * for the partials being rendered. The response data will be available to the client via

		 * the `render-partials-response` JS event, so the client can then inject the scripts and

		 * styles into the DOM if they have not already been enqueued there.

		 *

		 * If plugins do this, they'll need to take care for any scripts that do `document.write()`

		 * and make sure that these are not injected, or else to override the function to no-op,

		 * or else the page will be destroyed.

		 *

		 * Plugins should be aware that `$scripts` and `$styles` may eventually be included by

		 * default in the response.

		 *

		 * @since 4.5.0

		 *

		 * @param array $response {

		 *     Response.

		 *

		 *     @type array $contents Associative array mapping a partial ID its corresponding array of contents

		 *                           for the containers requested.

		 *     @type array $errors   List of errors triggered during rendering of partials, if `WP_DEBUG_DISPLAY`

		 *                           is enabled.

		 * }

		 * @param WP_Customize_Selective_Refresh $this     Selective refresh component.

		 * @param array                          $partials Placements' context data for the partials rendered in the request.

		 *                                                 The array is keyed by partial ID, with each item being an array of

		 *                                                 the placements' context data.

		 */

		$response = apply_filters( 'customize_render_partials_response', $response, $this, $partials );