• File: class-wp-interactivity-api.php
  • Full Path: /home/u505525515/domains/medineeestates.com/public_html/wp-includes/interactivity-api/class-wp-interactivity-api.php
  • Date Modified: 05/25/2026 6:29 AM
  • File size: 49.42 KB
  • MIME-type: text/x-php
  • Charset: utf-8
<?php
/**
 * Interactivity API: WP_Interactivity_API class.
 *
 * @package WordPress
 * @subpackage Interactivity API
 * @since 6.5.0
 */

/**
 * Class used to process the Interactivity API on the server.
 *
 * @since 6.5.0
 */
final class WP_Interactivity_API {
    /**
     * Holds the mapping of directive attribute names to their processor methods.
     *
     * @since 6.5.0
     * @var array
     */
    private static $directive_processors = array(
        'data-wp-interactive'   => 'data_wp_interactive_processor',
        'data-wp-router-region' => 'data_wp_router_region_processor',
        'data-wp-context'       => 'data_wp_context_processor',
        'data-wp-bind'          => 'data_wp_bind_processor',
        'data-wp-class'         => 'data_wp_class_processor',
        'data-wp-style'         => 'data_wp_style_processor',
        'data-wp-text'          => 'data_wp_text_processor',
        /*
         * `data-wp-each` needs to be processed in the last place because it moves
         * the cursor to the end of the processed items to prevent them to be
         * processed twice.
         */
        'data-wp-each'          => 'data_wp_each_processor',
    );

    /**
     * Holds the initial state of the different Interactivity API stores.
     *
     * This state is used during the server directive processing. Then, it is
     * serialized and sent to the client as part of the interactivity data to be
     * recovered during the hydration of the client interactivity stores.
     *
     * @since 6.5.0
     * @var array
     */
    private $state_data = array();

    /**
     * Holds the configuration required by the different Interactivity API stores.
     *
     * This configuration is serialized and sent to the client as part of the
     * interactivity data and can be accessed by the client interactivity stores.
     *
     * @since 6.5.0
     * @var array
     */
    private $config_data = array();

    /**
     * Keeps track of all derived state closures accessed during server-side rendering.
     *
     * This data is serialized and sent to the client as part of the interactivity
     * data, and is handled later in the client to support derived state props that
     * are lazily hydrated.
     *
     * @since 6.9.0
     * @var array
     */
    private $derived_state_closures = array();

    /**
     * Flag that indicates whether the `data-wp-router-region` directive has
     * been found in the HTML and processed.
     *
     * The value is saved in a private property of the WP_Interactivity_API
     * instance instead of using a static variable inside the processor
     * function, which would hold the same value for all instances
     * independently of whether they have processed any
     * `data-wp-router-region` directive or not.
     *
     * @since 6.5.0
     * @var bool
     */
    private $has_processed_router_region = false;

    /**
     * Set of script modules that can be loaded after client-side navigation.
     *
     * @since 6.9.0
     * @var array<string, true>
     */
    private $script_modules_that_can_load_on_client_navigation = array();

    /**
     * Stack of namespaces defined by `data-wp-interactive` directives, in
     * the order they are processed.
     *
     * This is only available during directive processing, otherwise it is `null`.
     *
     * @since 6.6.0
     * @var array<string>|null
     */
    private $namespace_stack = null;

    /**
     * Stack of contexts defined by `data-wp-context` directives, in
     * the order they are processed.
     *
     * This is only available during directive processing, otherwise it is `null`.
     *
     * @since 6.6.0
     * @var array<array<mixed>>|null
     */
    private $context_stack = null;

    /**
     * Representation in array format of the element currently being processed.
     *
     * This is only available during directive processing, otherwise it is `null`.
     *
     * @since 6.7.0
     * @var array{attributes: array<string, string|bool>}|null
     */
    private $current_element = null;

    /**
     * Gets and/or sets the initial state of an Interactivity API store for a
     * given namespace.
     *
     * If state for that store namespace already exists, it merges the new
     * provided state with the existing one.
     *
     * When no namespace is specified, it returns the state defined for the
     * current value in the internal namespace stack during a `process_directives` call.
     *
     * @since 6.5.0
     * @since 6.6.0 The `$store_namespace` param is optional.
     *
     * @param string $store_namespace Optional. The unique store namespace identifier.
     * @param array  $state           Optional. The array that will be merged with the existing state for the specified
     *                                store namespace.
     * @return array The current state for the specified store namespace. This will be the updated state if a $state
     *               argument was provided.
     */
    public function state( ?string $store_namespace = null, ?array $state = null ): array {
        if ( ! $store_namespace ) {
            if ( $state ) {
                _doing_it_wrong(
                    __METHOD__,
                    __( 'The namespace is required when state data is passed.' ),
                    '6.6.0'
                );
                return array();
            }
            if ( null !== $store_namespace ) {
                _doing_it_wrong(
                    __METHOD__,
                    __( 'The namespace should be a non-empty string.' ),
                    '6.6.0'
                );
                return array();
            }
            if ( null === $this->namespace_stack ) {
                _doing_it_wrong(
                    __METHOD__,
                    __( 'The namespace can only be omitted during directive processing.' ),
                    '6.6.0'
                );
                return array();
            }

            $store_namespace = end( $this->namespace_stack );
        }
        if ( ! isset( $this->state_data[ $store_namespace ] ) ) {
            $this->state_data[ $store_namespace ] = array();
        }
        if ( is_array( $state ) ) {
            $this->state_data[ $store_namespace ] = array_replace_recursive(
                $this->state_data[ $store_namespace ],
                $state
            );
        }
        return $this->state_data[ $store_namespace ];
    }

    /**
     * Gets and/or sets the configuration of the Interactivity API for a given
     * store namespace.
     *
     * If configuration for that store namespace exists, it merges the new
     * provided configuration with the existing one.
     *
     * @since 6.5.0
     *
     * @param string $store_namespace The unique store namespace identifier.
     * @param array  $config          Optional. The array that will be merged with the existing configuration for the
     *                                specified store namespace.
     * @return array The configuration for the specified store namespace. This will be the updated configuration if a
     *               $config argument was provided.
     */
    public function config( string $store_namespace, array $config = array() ): array {
        if ( ! isset( $this->config_data[ $store_namespace ] ) ) {
            $this->config_data[ $store_namespace ] = array();
        }
        if ( is_array( $config ) ) {
            $this->config_data[ $store_namespace ] = array_replace_recursive(
                $this->config_data[ $store_namespace ],
                $config
            );
        }
        return $this->config_data[ $store_namespace ];
    }

    /**
     * Prints the serialized client-side interactivity data.
     *
     * Encodes the config and initial state into JSON and prints them inside a
     * script tag of type "application/json". Once in the browser, the state will
     * be parsed and used to hydrate the client-side interactivity stores and the
     * configuration will be available using a `getConfig` utility.
     *
     * @since 6.5.0
     *
     * @deprecated 6.7.0 Client data passing is handled by the {@see "script_module_data_{$module_id}"} filter.
     */
    public function print_client_interactivity_data() {
        _deprecated_function( __METHOD__, '6.7.0' );
    }

    /**
     * Set client-side interactivity-router data.
     *
     * Once in the browser, the state will be parsed and used to hydrate the client-side
     * interactivity stores and the configuration will be available using a `getConfig` utility.
     *
     * @since 6.7.0
     *
     * @param array $data Data to filter.
     * @return array Data for the Interactivity Router script module.
     */
    public function filter_script_module_interactivity_router_data( array $data ): array {
        if ( ! isset( $data['i18n'] ) ) {
            $data['i18n'] = array();
        }
        $data['i18n']['loading'] = __( 'Loading page, please wait.' );
        $data['i18n']['loaded']  = __( 'Page Loaded.' );
        return $data;
    }

    /**
     * Set client-side interactivity data.
     *
     * Once in the browser, the state will be parsed and used to hydrate the client-side
     * interactivity stores and the configuration will be available using a `getConfig` utility.
     *
     * @since 6.7.0
     * @since 6.9.0 Serializes derived state props accessed during directive processing.
     *
     * @param array $data Data to filter.
     * @return array Data for the Interactivity API script module.
     */
    public function filter_script_module_interactivity_data( array $data ): array {
        if (
            empty( $this->state_data ) &&
            empty( $this->config_data ) &&
            empty( $this->derived_state_closures )
        ) {
            return $data;
        }

        $config = array();
        foreach ( $this->config_data as $key => $value ) {
            if ( ! empty( $value ) ) {
                $config[ $key ] = $value;
            }
        }
        if ( ! empty( $config ) ) {
            $data['config'] = $config;
        }

        $state = array();
        foreach ( $this->state_data as $key => $value ) {
            if ( ! empty( $value ) ) {
                $state[ $key ] = $value;
            }
        }
        if ( ! empty( $state ) ) {
            $data['state'] = $state;
        }

        $derived_props = array();
        foreach ( $this->derived_state_closures as $key => $value ) {
            if ( ! empty( $value ) ) {
                $derived_props[ $key ] = $value;
            }
        }
        if ( ! empty( $derived_props ) ) {
            $data['derivedStateClosures'] = $derived_props;
        }

        return $data;
    }

    /**
     * Returns the latest value on the context stack with the passed namespace.
     *
     * When the namespace is omitted, it uses the current namespace on the
     * namespace stack during a `process_directives` call.
     *
     * @since 6.6.0
     *
     * @param string $store_namespace Optional. The unique store namespace identifier.
     */
    public function get_context( ?string $store_namespace = null ): array {
        if ( null === $this->context_stack ) {
            _doing_it_wrong(
                __METHOD__,
                __( 'The context can only be read during directive processing.' ),
                '6.6.0'
            );
            return array();
        }

        if ( ! $store_namespace ) {
            if ( null !== $store_namespace ) {
                _doing_it_wrong(
                    __METHOD__,
                    __( 'The namespace should be a non-empty string.' ),
                    '6.6.0'
                );
                return array();
            }

            $store_namespace = end( $this->namespace_stack );
        }

        $context = end( $this->context_stack );

        return ( $store_namespace && $context && isset( $context[ $store_namespace ] ) )
            ? $context[ $store_namespace ]
            : array();
    }

    /**
     * Returns an array representation of the current element being processed.
     *
     * The returned array contains a copy of the element attributes.
     *
     * @since 6.7.0
     *
     * @return array{attributes: array<string, string|bool>}|null Current element.
     */
    public function get_element(): ?array {
        if ( null === $this->current_element ) {
            _doing_it_wrong(
                __METHOD__,
                __( 'The element can only be read during directive processing.' ),
                '6.7.0'
            );
        }

        return $this->current_element;
    }

    /**
     * Registers the `@wordpress/interactivity` script modules.
     *
     * @deprecated 6.7.0 Script Modules registration is handled by {@see wp_default_script_modules()}.
     *
     * @since 6.5.0
     */
    public function register_script_modules() {
        _deprecated_function( __METHOD__, '6.7.0', 'wp_default_script_modules' );
    }

    /**
     * Adds the necessary hooks for the Interactivity API.
     *
     * @since 6.5.0
     * @since 6.9.0 Adds support for client-side navigation in script modules.
     */
    public function add_hooks() {
        add_filter( 'script_module_data_@wordpress/interactivity', array( $this, 'filter_script_module_interactivity_data' ) );
        add_filter( 'script_module_data_@wordpress/interactivity-router', array( $this, 'filter_script_module_interactivity_router_data' ) );
        add_filter( 'wp_script_attributes', array( $this, 'add_load_on_client_navigation_attribute_to_script_modules' ), 10, 1 );
    }

    /**
     * Adds the `data-wp-router-options` attribute to script modules that
     * support client-side navigation.
     *
     * This method filters the script attributes to include loading instructions
     * for the Interactivity API router, indicating which modules can be loaded
     * during client-side navigation.
     *
     * @since 6.9.0
     *
     * @param array<string, string|true>|mixed $attributes The script tag attributes.
     * @return array The modified script tag attributes.
     */
    public function add_load_on_client_navigation_attribute_to_script_modules( $attributes ) {
        if (
            is_array( $attributes ) &&
            isset( $attributes['type'], $attributes['id'] ) &&
            'module' === $attributes['type'] &&
            array_key_exists(
                preg_replace( '/-js-module$/', '', $attributes['id'] ),
                $this->script_modules_that_can_load_on_client_navigation
            )
        ) {
            $attributes['data-wp-router-options'] = wp_json_encode( array( 'loadOnClientNavigation' => true ) );
        }
        return $attributes;
    }

    /**
     * Marks a script module as compatible with client-side navigation.
     *
     * This method registers a script module to be loaded during client-side
     * navigation in the Interactivity API router. Script modules marked with
     * this method will have the `loadOnClientNavigation` option enabled in the
     * `data-wp-router-options` directive.
     *
     * @since 6.9.0
     *
     * @param string $script_module_id The script module identifier.
     */
    public function add_client_navigation_support_to_script_module( string $script_module_id ) {
        $this->script_modules_that_can_load_on_client_navigation[ $script_module_id ] = true;
    }

    /**
     * Processes the interactivity directives contained within the HTML content
     * and updates the markup accordingly.
     *
     * @since 6.5.0
     *
     * @param string $html The HTML content to process.
     * @return string The processed HTML content. It returns the original content when the HTML contains unbalanced tags.
     */
    public function process_directives( string $html ): string {
        if ( ! str_contains( $html, 'data-wp-' ) ) {
            return $html;
        }

        $this->namespace_stack = array();
        $this->context_stack   = array();

        $result = $this->_process_directives( $html );

        $this->namespace_stack = null;
        $this->context_stack   = null;

        return $result ?? $html;
    }

    /**
     * Processes the interactivity directives contained within the HTML content
     * and updates the markup accordingly.
     *
     * It uses the WP_Interactivity_API instance's context and namespace stacks,
     * which are shared between all calls.
     *
     * This method returns null if the HTML contains unbalanced tags.
     *
     * @since 6.6.0
     *
     * @param string $html The HTML content to process.
     * @return string|null The processed HTML content. It returns null when the HTML contains unbalanced tags.
     */
    private function _process_directives( string $html ) {
        $p          = new WP_Interactivity_API_Directives_Processor( $html );
        $tag_stack  = array();
        $unbalanced = false;

        $directive_processor_prefixes          = array_keys( self::$directive_processors );
        $directive_processor_prefixes_reversed = array_reverse( $directive_processor_prefixes );

        /*
         * Save the current size for each stack to restore them in case
         * the processing finds unbalanced tags.
         */
        $namespace_stack_size = count( $this->namespace_stack );
        $context_stack_size   = count( $this->context_stack );

        while ( $p->next_tag( array( 'tag_closers' => 'visit' ) ) ) {
            $tag_name = $p->get_tag();

            /*
             * Directives inside SVG and MATH tags are not processed,
             * as they are not compatible with the Tag Processor yet.
             * We still process the rest of the HTML.
             */
            if ( 'SVG' === $tag_name || 'MATH' === $tag_name ) {
                if ( $p->get_attribute_names_with_prefix( 'data-wp-' ) ) {
                    /* translators: 1: SVG or MATH HTML tag, 2: Namespace of the interactive block. */
                    $message = sprintf( __( 'Interactivity directives were detected on an incompatible %1$s tag when processing "%2$s". These directives will be ignored in the server side render.' ), $tag_name, end( $this->namespace_stack ) );
                    _doing_it_wrong( __METHOD__, $message, '6.6.0' );
                }
                $p->skip_to_tag_closer();
                continue;
            }

            if ( $p->is_tag_closer() ) {
                list( $opening_tag_name, $directives_prefixes ) = ! empty( $tag_stack ) ? end( $tag_stack ) : array( null, null );

                if ( 0 === count( $tag_stack ) || $opening_tag_name !== $tag_name ) {

                    /*
                     * If the tag stack is empty or the matching opening tag is not the
                     * same than the closing tag, it means the HTML is unbalanced and it
                     * stops processing it.
                     */
                    $unbalanced = true;
                    break;
                } else {
                    // Remove the last tag from the stack.
                    array_pop( $tag_stack );
                }
            } else {
                $each_child_attrs = $p->get_attribute_names_with_prefix( 'data-wp-each-child' );
                if ( null === $each_child_attrs ) {
                    continue;
                }

                if ( 0 !== count( $each_child_attrs ) ) {
                    /*
                     * If the tag has a `data-wp-each-child` directive, jump to its closer
                     * tag because those tags have already been processed.
                     */
                    $p->next_balanced_tag_closer_tag();
                    continue;
                } else {
                    $directives_prefixes = array();

                    // Checks if there is a server directive processor registered for each directive.
                    foreach ( $p->get_attribute_names_with_prefix( 'data-wp-' ) as $attribute_name ) {
                        $parsed_directive = $this->parse_directive_name( $attribute_name );
                        if ( empty( $parsed_directive ) ) {
                            continue;
                        }
                        $directive_prefix = 'data-wp-' . $parsed_directive['prefix'];
                        if ( array_key_exists( $directive_prefix, self::$directive_processors ) ) {
                            $directives_prefixes[] = $directive_prefix;
                        }
                    }

                    /*
                     * If this tag will visit its closer tag, it adds it to the tag stack
                     * so it can process its closing tag and check for unbalanced tags.
                     */
                    if ( $p->has_and_visits_its_closer_tag() ) {
                        $tag_stack[] = array( $tag_name, $directives_prefixes );
                    }
                }
            }
            /*
             * If the matching opener tag didn't have any directives, it can skip the
             * processing.
             */
            if ( 0 === count( $directives_prefixes ) ) {
                continue;
            }

            // Directive processing might be different depending on if it is entering the tag or exiting it.
            $modes = array(
                'enter' => ! $p->is_tag_closer(),
                'exit'  => $p->is_tag_closer() || ! $p->has_and_visits_its_closer_tag(),
            );

            // Get the element attributes to include them in the element representation.
            $element_attrs = array();
            $attr_names    = $p->get_attribute_names_with_prefix( '' ) ?? array();

            foreach ( $attr_names as $name ) {
                $element_attrs[ $name ] = $p->get_attribute( $name );
            }

            // Assign the current element right before running its directive processors.
            $this->current_element = array(
                'attributes' => $element_attrs,
            );

            foreach ( $modes as $mode => $should_run ) {
                if ( ! $should_run ) {
                    continue;
                }

                /*
                 * Sorts the attributes by the order of the `directives_processor` array
                 * and checks what directives are present in this element.
                 */
                $existing_directives_prefixes = array_intersect(
                    'enter' === $mode ? $directive_processor_prefixes : $directive_processor_prefixes_reversed,
                    $directives_prefixes
                );
                foreach ( $existing_directives_prefixes as $directive_prefix ) {
                    $func = is_array( self::$directive_processors[ $directive_prefix ] )
                        ? self::$directive_processors[ $directive_prefix ]
                        : array( $this, self::$directive_processors[ $directive_prefix ] );

                    call_user_func_array( $func, array( $p, $mode, &$tag_stack ) );
                }
            }

            // Clear the current element.
            $this->current_element = null;
        }

        if ( $unbalanced ) {
            // Reset the namespace and context stacks to their previous values.
            array_splice( $this->namespace_stack, $namespace_stack_size );
            array_splice( $this->context_stack, $context_stack_size );
        }

        /*
         * It returns null if the HTML is unbalanced because unbalanced HTML is
         * not safe to process. In that case, the Interactivity API runtime will
         * update the HTML on the client side during the hydration. It will display
         * a notice to the developer in the console to inform them about the issue.
         */
        if ( $unbalanced || 0 < count( $tag_stack ) ) {
            return null;
        }

        return $p->get_updated_html();
    }

    /**
     * Evaluates the reference path passed to a directive based on the current
     * store namespace, state and context.
     *
     * @since 6.5.0
     * @since 6.6.0 The function now adds a warning when the namespace is null, falsy, or the directive value is empty.
     * @since 6.6.0 Removed `default_namespace` and `context` arguments.
     * @since 6.6.0 Add support for derived state.
     * @since 6.9.0 Receive $entry as an argument instead of the directive value string.
     *
     * @param array $entry An array containing a whole directive entry with its namespace, value, suffix, or unique ID.
     * @return mixed|null The result of the evaluation. Null if the reference path doesn't exist or the namespace is falsy.
     */
    private function evaluate( $entry ) {
        $context                               = end( $this->context_stack );
        ['namespace' => $ns, 'value' => $path] = $entry;

        if ( ! $ns || ! $path ) {
            /* translators: %s: The directive value referenced. */
            $message = sprintf( __( 'Namespace or reference path cannot be empty. Directive value referenced: %s' ), json_encode( $entry ) );
            _doing_it_wrong( __METHOD__, $message, '6.6.0' );
            return null;
        }

        $store = array(
            'state'   => $this->state_data[ $ns ] ?? array(),
            'context' => $context[ $ns ] ?? array(),
        );

        // Checks if the reference path is preceded by a negation operator (!).
        $should_negate_value = '!' === $path[0];
        $path                = $should_negate_value ? substr( $path, 1 ) : $path;

        // Extracts the value from the store using the reference path.
        $path_segments = explode( '.', $path );
        $current       = $store;
        foreach ( $path_segments as $index => $path_segment ) {
            /*
             * Special case for numeric arrays and strings. Add length
             * property mimicking JavaScript behavior.
             *
             * @since 6.8.0
             */
            if ( 'length' === $path_segment ) {
                if ( is_array( $current ) && array_is_list( $current ) ) {
                    $current = count( $current );
                    break;
                }

                if ( is_string( $current ) ) {
                    /*
                     * Differences in encoding between PHP strings and
                     * JavaScript mean that it's complicated to calculate
                     * the string length JavaScript would see from PHP.
                     * `strlen` is a reasonable approximation.
                     *
                     * Users that desire a more precise length likely have
                     * more precise needs than "bytelength" and should
                     * implement their own length calculation in derived
                     * state taking into account encoding and their desired
                     * output (codepoints, graphemes, bytes, etc.).
                     */
                    $current = strlen( $current );
                    break;
                }
            }

            if ( ( is_array( $current ) || $current instanceof ArrayAccess ) && isset( $current[ $path_segment ] ) ) {
                $current = $current[ $path_segment ];
            } elseif ( is_object( $current ) && isset( $current->$path_segment ) ) {
                $current = $current->$path_segment;
            } else {
                $current = null;
                break;
            }

            if ( $current instanceof Closure ) {
                /*
                 * This state getter's namespace is added to the stack so that
                 * `state()` or `get_config()` read that namespace when called
                 * without specifying one.
                 */
                array_push( $this->namespace_stack, $ns );
                try {
                    $current = $current();

                    /*
                     * Tracks derived state properties that are accessed during
                     * rendering.
                     *
                     * @since 6.9.0
                     */
                    $this->derived_state_closures[ $ns ] = $this->derived_state_closures[ $ns ] ?? array();

                    // Builds path for the current property and add it to tracking if not already present.
                    $current_path = implode( '.', array_slice( $path_segments, 0, $index + 1 ) );
                    if ( ! in_array( $current_path, $this->derived_state_closures[ $ns ], true ) ) {
                        $this->derived_state_closures[ $ns ][] = $current_path;
                    }
                } catch ( Throwable $e ) {
                    _doing_it_wrong(
                        __METHOD__,
                        sprintf(
                            /* translators: 1: Path pointing to an Interactivity API state property, 2: Namespace for an Interactivity API store. */
                            __( 'Uncaught error executing a derived state callback with path "%1$s" and namespace "%2$s".' ),
                            $path,
                            $ns
                        ),
                        '6.6.0'
                    );
                    return null;
                } finally {
                    // Remove the property's namespace from the stack.
                    array_pop( $this->namespace_stack );
                }
            }
        }

        // Returns the opposite if it contains a negation operator (!).
        return $should_negate_value ? ! $current : $current;
    }

    /**
     * Parse the directive name to extract the following parts:
     * - Prefix: The main directive name without "data-wp-".
     * - Suffix: An optional suffix used during directive processing, extracted after the first double hyphen "--".
     * - Unique ID: An optional unique identifier, extracted after the first triple hyphen "---".
     *
     * This function has an equivalent version for the client side.
     * See `parseDirectiveName` in https://github.com/WordPress/gutenberg/blob/trunk/packages/interactivity/src/vdom.ts.:
     *
     * See examples in the function unit tests `test_parse_directive_name`.
     *
     * @since 6.9.0
     *
     * @param string $directive_name The directive attribute name.
     * @return array An array containing the directive prefix, optional suffix, and optional unique ID.
     */
    private function parse_directive_name( string $directive_name ): ?array {
        // Remove the first 8 characters (assumes "data-wp-" prefix)
        $name = substr( $directive_name, 8 );

        // Check for invalid characters (anything not a-z, 0-9, -, or _)
        if ( preg_match( '/[^a-z0-9\-_]/i', $name ) ) {
            return null;
        }

        // Find the first occurrence of '--' to separate the prefix
        $suffix_index = strpos( $name, '--' );

        if ( false === $suffix_index ) {
            return array(
                'prefix'    => $name,
                'suffix'    => null,
                'unique_id' => null,
            );
        }

        $prefix    = substr( $name, 0, $suffix_index );
        $remaining = substr( $name, $suffix_index );

        // If remaining starts with '---' but not '----', it's a unique_id
        if ( '---' === substr( $remaining, 0, 3 ) && '-' !== ( $remaining[3] ?? '' ) ) {
            return array(
                'prefix'    => $prefix,
                'suffix'    => null,
                'unique_id' => '---' !== $remaining ? substr( $remaining, 3 ) : null,
            );
        }

        // Otherwise, remove the first two dashes for a potential suffix
        $suffix = substr( $remaining, 2 );

        // Look for '---' in the suffix for a unique_id
        $unique_id_index = strpos( $suffix, '---' );

        if ( false !== $unique_id_index && '-' !== ( $suffix[ $unique_id_index + 3 ] ?? '' ) ) {
            $unique_id = substr( $suffix, $unique_id_index + 3 );
            $suffix    = substr( $suffix, 0, $unique_id_index );
            return array(
                'prefix'    => $prefix,
                'suffix'    => empty( $suffix ) ? null : $suffix,
                'unique_id' => empty( $unique_id ) ? null : $unique_id,
            );
        }

        return array(
            'prefix'    => $prefix,
            'suffix'    => empty( $suffix ) ? null : $suffix,
            'unique_id' => null,
        );
    }

    /**
     * Parses and extracts the namespace and reference path from the given
     * directive attribute value.
     *
     * If the value doesn't contain an explicit namespace, it returns the
     * default one. If the value contains a JSON object instead of a reference
     * path, the function tries to parse it and return the resulting array. If
     * the value contains strings that represent booleans ("true" and "false"),
     * numbers ("1" and "1.2") or "null", the function also transform them to
     * regular booleans, numbers and `null`.
     *
     * Example:
     *
     *     extract_directive_value( 'actions.foo', 'myPlugin' )                      => array( 'myPlugin', 'actions.foo' )
     *     extract_directive_value( 'otherPlugin::actions.foo', 'myPlugin' )         => array( 'otherPlugin', 'actions.foo' )
     *     extract_directive_value( '{ "isOpen": false }', 'myPlugin' )              => array( 'myPlugin', array( 'isOpen' => false ) )
     *     extract_directive_value( 'otherPlugin::{ "isOpen": false }', 'myPlugin' ) => array( 'otherPlugin', array( 'isOpen' => false ) )
     *
     * @since 6.5.0
     *
     * @param string|true $directive_value   The directive attribute value. It can be `true` when it's a boolean
     *                                       attribute.
     * @param string|null $default_namespace Optional. The default namespace if none is explicitly defined.
     * @return array An array containing the namespace in the first item and the JSON, the reference path, or null on the
     *               second item.
     */
    private function extract_directive_value( $directive_value, $default_namespace = null ): array {
        if ( empty( $directive_value ) || is_bool( $directive_value ) ) {
            return array( $default_namespace, null );
        }

        // Replaces the value and namespace if there is a namespace in the value.
        if ( 1 === preg_match( '/^([\w\-_\/]+)::./', $directive_value ) ) {
            list($default_namespace, $directive_value) = explode( '::', $directive_value, 2 );
        }

        /*
         * Tries to decode the value as a JSON object. If it fails and the value
         * isn't `null`, it returns the value as it is. Otherwise, it returns the
         * decoded JSON or null for the string `null`.
         */
        $decoded_json = json_decode( $directive_value, true );
        if ( null !== $decoded_json || 'null' === $directive_value ) {
            $directive_value = $decoded_json;
        }

        return array( $default_namespace, $directive_value );
    }

    /**
     * Parse the HTML element and get all the valid directives with the given prefix.
     *
     * @since 6.9.0
     *
     * @param WP_Interactivity_API_Directives_Processor $p      The directives processor instance.
     * @param string                                    $prefix The directive prefix to filter by.
     * @return array An array of entries containing the directive namespace, value, suffix, and unique ID.
     */
    private function get_directive_entries( WP_Interactivity_API_Directives_Processor $p, string $prefix ) {
        $directive_attributes = $p->get_attribute_names_with_prefix( 'data-wp-' . $prefix );
        $entries              = array();
        foreach ( $directive_attributes as $attribute_name ) {
            [ 'prefix' => $attr_prefix, 'suffix' => $suffix, 'unique_id' => $unique_id] = $this->parse_directive_name( $attribute_name );
            // Ensure it is the desired directive.
            if ( $prefix !== $attr_prefix ) {
                continue;
            }
            list( $namespace, $value ) = $this->extract_directive_value( $p->get_attribute( $attribute_name ), end( $this->namespace_stack ) );
            $entries[]                 = array(
                'namespace' => $namespace,
                'value'     => $value,
                'suffix'    => $suffix,
                'unique_id' => $unique_id,
            );
        }
        // Sort directive entries to ensure stable ordering with the client.
        // Put nulls first, then sort by suffix and finally by uniqueIds.
        usort(
            $entries,
            function ( $a, $b ) {
                $a_suffix = $a['suffix'] ?? '';
                $b_suffix = $b['suffix'] ?? '';
                if ( $a_suffix !== $b_suffix ) {
                    return $a_suffix <=> $b_suffix;
                }
                $a_id = $a['unique_id'] ?? '';
                $b_id = $b['unique_id'] ?? '';
                return $a_id <=> $b_id;
            }
        );
        return $entries;
    }

    /**
     * Transforms a kebab-case string to camelCase.
     *
     * @since 6.5.0
     *
     * @param string $str The kebab-case string to transform to camelCase.
     * @return string The transformed camelCase string.
     */
    private function kebab_to_camel_case( string $str ): string {
        return lcfirst(
            preg_replace_callback(
                '/(-)([a-z])/',
                function ( $matches ) {
                    return strtoupper( $matches[2] );
                },
                strtolower( rtrim( $str, '-' ) )
            )
        );
    }

    /**
     * Processes the `data-wp-interactive` directive.
     *
     * It adds the default store namespace defined in the directive value to the
     * stack so that it's available for the nested interactivity elements.
     *
     * @since 6.5.0
     *
     * @param WP_Interactivity_API_Directives_Processor $p    The directives processor instance.
     * @param string                                    $mode Whether the processing is entering or exiting the tag.
     */
    private function data_wp_interactive_processor( WP_Interactivity_API_Directives_Processor $p, string $mode ) {
        // When exiting tags, it removes the last namespace from the stack.
        if ( 'exit' === $mode ) {
            array_pop( $this->namespace_stack );
            return;
        }

        // Tries to decode the `data-wp-interactive` attribute value.
        $attribute_value = $p->get_attribute( 'data-wp-interactive' );

        /*
         * Pushes the newly defined namespace or the current one if the
         * `data-wp-interactive` definition was invalid or does not contain a
         * namespace. It does so because the function pops out the current namespace
         * from the stack whenever it finds a `data-wp-interactive`'s closing tag,
         * independently of whether the previous `data-wp-interactive` definition
         * contained a valid namespace.
         */
        $new_namespace = null;
        if ( is_string( $attribute_value ) && ! empty( $attribute_value ) ) {
            $decoded_json = json_decode( $attribute_value, true );
            if ( is_array( $decoded_json ) ) {
                $new_namespace = $decoded_json['namespace'] ?? null;
            } else {
                $new_namespace = $attribute_value;
            }
        }
        $this->namespace_stack[] = ( $new_namespace && 1 === preg_match( '/^([\w\-_\/]+)/', $new_namespace ) )
            ? $new_namespace
            : end( $this->namespace_stack );
    }

    /**
     * Processes the `data-wp-context` directive.
     *
     * It adds the context defined in the directive value to the stack so that
     * it's available for the nested interactivity elements.
     *
     * @since 6.5.0
     *
     * @param WP_Interactivity_API_Directives_Processor $p               The directives processor instance.
     * @param string                                    $mode            Whether the processing is entering or exiting the tag.
     */
    private function data_wp_context_processor( WP_Interactivity_API_Directives_Processor $p, string $mode ) {
        // When exiting tags, it removes the last context from the stack.
        if ( 'exit' === $mode ) {
            array_pop( $this->context_stack );
            return;
        }

        $entries = $this->get_directive_entries( $p, 'context' );
        $context = end( $this->context_stack ) !== false ? end( $this->context_stack ) : array();
        foreach ( $entries as $entry ) {
            if ( null !== $entry['suffix'] ) {
                continue;
            }

            $context = array_replace_recursive(
                $context,
                array( $entry['namespace'] => is_array( $entry['value'] ) ? $entry['value'] : array() )
            );
        }
        $this->context_stack[] = $context;
    }

    /**
     * Processes the `data-wp-bind` directive.
     *
     * It updates or removes the bound attributes based on the evaluation of its
     * associated reference.
     *
     * @since 6.5.0
     *
     * @param WP_Interactivity_API_Directives_Processor $p               The directives processor instance.
     * @param string                                    $mode            Whether the processing is entering or exiting the tag.
     */
    private function data_wp_bind_processor( WP_Interactivity_API_Directives_Processor $p, string $mode ) {
        if ( 'enter' === $mode ) {
            $entries = $this->get_directive_entries( $p, 'bind' );
            foreach ( $entries as $entry ) {
                if ( empty( $entry['suffix'] ) || null !== $entry['unique_id'] ) {
                        continue;
                }

                // Skip if the suffix is an event handler.
                if ( str_starts_with( $entry['suffix'], 'on' ) ) {
                    _doing_it_wrong(
                        __METHOD__,
                        sprintf(
                            /* translators: %s: The directive, e.g. data-wp-on--click. */
                            __( 'Binding event handler attributes is not supported. Please use "%s" instead.' ),
                            esc_attr( 'data-wp-on--' . substr( $entry['suffix'], 2 ) )
                        ),
                        '6.9.2'
                    );
                    continue;
                }

                $result = $this->evaluate( $entry );

                if (
                    null !== $result &&
                    (
                        false !== $result ||
                        ( strlen( $entry['suffix'] ) > 5 && '-' === $entry['suffix'][4] )
                    )
                ) {
                    /*
                     * If the result of the evaluation is a boolean and the attribute is
                     * `aria-` or `data-, convert it to a string "true" or "false". It
                     * follows the exact same logic as Preact because it needs to
                     * replicate what Preact will later do in the client:
                     * https://github.com/preactjs/preact/blob/ea49f7a0f9d1ff2c98c0bdd66aa0cbc583055246/src/diff/props.js#L131C24-L136
                     */
                    if (
                        is_bool( $result ) &&
                        ( strlen( $entry['suffix'] ) > 5 && '-' === $entry['suffix'][4] )
                    ) {
                        $result = $result ? 'true' : 'false';
                    }
                    $p->set_attribute( $entry['suffix'], $result );
                } else {
                    $p->remove_attribute( $entry['suffix'] );
                }
            }
        }
    }

    /**
     * Processes the `data-wp-class` directive.
     *
     * It adds or removes CSS classes in the current HTML element based on the
     * evaluation of its associated references.
     *
     * @since 6.5.0
     *
     * @param WP_Interactivity_API_Directives_Processor $p               The directives processor instance.
     * @param string                                    $mode            Whether the processing is entering or exiting the tag.
     */
    private function data_wp_class_processor( WP_Interactivity_API_Directives_Processor $p, string $mode ) {
        if ( 'enter' === $mode ) {
            $all_class_directives = $p->get_attribute_names_with_prefix( 'data-wp-class--' );
            $entries              = $this->get_directive_entries( $p, 'class' );
            foreach ( $entries as $entry ) {
                if ( empty( $entry['suffix'] ) ) {
                    continue;
                }
                $class_name = isset( $entry['unique_id'] ) && $entry['unique_id']
                    ? "{$entry['suffix']}---{$entry['unique_id']}"
                    : $entry['suffix'];

                if ( empty( $class_name ) ) {
                    return;
                }

                $result = $this->evaluate( $entry );

                if ( $result ) {
                    $p->add_class( $class_name );
                } else {
                    $p->remove_class( $class_name );
                }
            }
        }
    }

    /**
     * Processes the `data-wp-style` directive.
     *
     * It updates the style attribute value of the current HTML element based on
     * the evaluation of its associated references.
     *
     * @since 6.5.0
     *
     * @param WP_Interactivity_API_Directives_Processor $p               The directives processor instance.
     * @param string                                    $mode            Whether the processing is entering or exiting the tag.
     */
    private function data_wp_style_processor( WP_Interactivity_API_Directives_Processor $p, string $mode ) {
        if ( 'enter' === $mode ) {
            $entries = $this->get_directive_entries( $p, 'style' );
            foreach ( $entries as $entry ) {
                $style_property = $entry['suffix'];
                if ( empty( $style_property ) || null !== $entry['unique_id'] ) {
                    continue;
                }

                $style_property_value  = $this->evaluate( $entry );
                $style_attribute_value = $p->get_attribute( 'style' );
                $style_attribute_value = ( $style_attribute_value && ! is_bool( $style_attribute_value ) ) ? $style_attribute_value : '';

                /*
                 * Checks first if the style property is not falsy and the style
                 * attribute value is not empty because if it is, it doesn't need to
                 * update the attribute value.
                 */
                if ( $style_property_value || $style_attribute_value ) {
                    $style_attribute_value = $this->merge_style_property( $style_attribute_value, $style_property, $style_property_value );
                    /*
                     * If the style attribute value is not empty, it sets it. Otherwise,
                     * it removes it.
                     */
                    if ( ! empty( $style_attribute_value ) ) {
                        $p->set_attribute( 'style', $style_attribute_value );
                    } else {
                        $p->remove_attribute( 'style' );
                    }
                }
            }
        }
    }

    /**
     * Merges an individual style property in the `style` attribute of an HTML
     * element, updating or removing the property when necessary.
     *
     * If a property is modified, the old one is removed and the new one is added
     * at the end of the list.
     *
     * @since 6.5.0
     *
     * Example:
     *
     *     merge_style_property( 'color:green;', 'color', 'red' )      => 'color:red;'
     *     merge_style_property( 'background:green;', 'color', 'red' ) => 'background:green;color:red;'
     *     merge_style_property( 'color:green;', 'color', null )       => ''
     *
     * @param string            $style_attribute_value The current style attribute value.
     * @param string            $style_property_name   The style property name to set.
     * @param string|false|null $style_property_value  The value to set for the style property. With false, null or an
     *                                                 empty string, it removes the style property.
     * @return string The new style attribute value after the specified property has been added, updated or removed.
     */
    private function merge_style_property( string $style_attribute_value, string $style_property_name, $style_property_value ): string {
        $style_assignments    = explode( ';', $style_attribute_value );
        $result               = array();
        $style_property_value = ! empty( $style_property_value ) ? rtrim( trim( $style_property_value ), ';' ) : null;
        $new_style_property   = $style_property_value ? $style_property_name . ':' . $style_property_value . ';' : '';

        // Generates an array with all the properties but the modified one.
        foreach ( $style_assignments as $style_assignment ) {
            if ( empty( trim( $style_assignment ) ) ) {
                continue;
            }
            list( $name, $value ) = explode( ':', $style_assignment );
            if ( trim( $name ) !== $style_property_name ) {
                $result[] = trim( $name ) . ':' . trim( $value ) . ';';
            }
        }

        // Adds the new/modified property at the end of the list.
        $result[] = $new_style_property;

        return implode( '', $result );
    }

    /**
     * Processes the `data-wp-text` directive.
     *
     * It updates the inner content of the current HTML element based on the
     * evaluation of its associated reference.
     *
     * @since 6.5.0
     *
     * @param WP_Interactivity_API_Directives_Processor $p               The directives processor instance.
     * @param string                                    $mode            Whether the processing is entering or exiting the tag.
     */
    private function data_wp_text_processor( WP_Interactivity_API_Directives_Processor $p, string $mode ) {
        if ( 'enter' === $mode ) {
            $entries     = $this->get_directive_entries( $p, 'text' );
            $valid_entry = null;
            // Get the first valid `data-wp-text` entry without suffix or unique ID.
            foreach ( $entries as $entry ) {
                if ( null === $entry['suffix'] && null === $entry['unique_id'] && ! empty( $entry['value'] ) ) {
                    $valid_entry = $entry;
                    break;
                }
            }
            if ( null === $valid_entry ) {
                return;
            }
            $result = $this->evaluate( $valid_entry );

            /*
             * Follows the same logic as Preact in the client and only changes the
             * content if the value is a string or a number. Otherwise, it removes the
             * content.
             */
            if ( is_string( $result ) || is_numeric( $result ) ) {
                $p->set_content_between_balanced_tags( esc_html( $result ) );
            } else {
                $p->set_content_between_balanced_tags( '' );
            }
        }
    }

    /**
     * Returns the CSS styles for animating the top loading bar in the router.
     *
     * @since 6.5.0
     *
     * @return string The CSS styles for the router's top loading bar animation.
     */
    private function get_router_animation_styles(): string {
        return <<<CSS
            .wp-interactivity-router-loading-bar {
                position: fixed;
                top: 0;
                left: 0;
                margin: 0;
                padding: 0;
                width: 100vw;
                max-width: 100vw !important;
                height: 4px;
                background-color: #000;
                opacity: 0
            }
            .wp-interactivity-router-loading-bar.start-animation {
                animation: wp-interactivity-router-loading-bar-start-animation 30s cubic-bezier(0.03, 0.5, 0, 1) forwards
            }
            .wp-interactivity-router-loading-bar.finish-animation {
                animation: wp-interactivity-router-loading-bar-finish-animation 300ms ease-in
            }
            @keyframes wp-interactivity-router-loading-bar-start-animation {
                0% { transform: scaleX(0); transform-origin: 0 0; opacity: 1 }
                100% { transform: scaleX(1); transform-origin: 0 0; opacity: 1 }
            }
            @keyframes wp-interactivity-router-loading-bar-finish-animation {
                0% { opacity: 1 }
                50% { opacity: 1 }
                100% { opacity: 0 }
            }
CSS;
    }

    /**
     * Deprecated.
     *
     * @since 6.5.0
     * @deprecated 6.7.0 Use {@see WP_Interactivity_API::print_router_markup} instead.
     */
    public function print_router_loading_and_screen_reader_markup() {
        _deprecated_function( __METHOD__, '6.7.0', 'WP_Interactivity_API::print_router_markup' );

        // Call the new method.
        $this->print_router_markup();
    }

    /**
     * Outputs markup for the @wordpress/interactivity-router script module.
     *
     * This method prints a div element representing a loading bar visible during
     * navigation.
     *
     * @since 6.7.0
     */
    public function print_router_markup() {
        echo <<<HTML
            <div
                class="wp-interactivity-router-loading-bar"
                data-wp-interactive="core/router/private"
                data-wp-class--start-animation="state.navigation.hasStarted"
                data-wp-class--finish-animation="state.navigation.hasFinished"
            ></div>
HTML;
    }

    /**
     * Processes the `data-wp-router-region` directive.
     *
     * It renders in the footer a set of HTML elements to notify users about
     * client-side navigations. More concretely, the elements added are 1) a
     * top loading bar to visually inform that a navigation is in progress
     * and 2) an `aria-live` region for accessible navigation announcements.
     *
     * @since 6.5.0
     *
     * @param WP_Interactivity_API_Directives_Processor $p               The directives processor instance.
     * @param string                                    $mode            Whether the processing is entering or exiting the tag.
     */
    private function data_wp_router_region_processor( WP_Interactivity_API_Directives_Processor $p, string $mode ) {
        if ( 'enter' === $mode && ! $this->has_processed_router_region ) {
            $this->has_processed_router_region = true;

            // Initializes the `state.url` property from the server.
            $this->state(
                'core/router',
                array(
                    'url' => get_self_link(),
                )
            );

            // Enqueues as an inline style.
            wp_register_style( 'wp-interactivity-router-animations', false );
            wp_add_inline_style( 'wp-interactivity-router-animations', $this->get_router_animation_styles() );
            wp_enqueue_style( 'wp-interactivity-router-animations' );

            // Adds the necessary markup to the footer.
            add_action( 'wp_footer', array( $this, 'print_router_markup' ) );
        }
    }

    /**
     * Processes the `data-wp-each` directive.
     *
     * This directive gets an array passed as reference and iterates over it
     * generating new content for each item based on the inner markup of the
     * `template` tag.
     *
     * @since 6.5.0
     * @since 6.9.0 Include the list path in the rendered `data-wp-each-child` directives.
     *
     * @param WP_Interactivity_API_Directives_Processor $p               The directives processor instance.
     * @param string                                    $mode            Whether the processing is entering or exiting the tag.
     * @param array                                     $tag_stack       The reference to the tag stack.
     */
    private function data_wp_each_processor( WP_Interactivity_API_Directives_Processor $p, string $mode, array &$tag_stack ) {
        if ( 'enter' === $mode && 'TEMPLATE' === $p->get_tag() ) {
            $entries = $this->get_directive_entries( $p, 'each' );
            if ( count( $entries ) > 1 || empty( $entries ) ) {
                // There should be only one `data-wp-each` directive per template tag.
                return;
            }
            $entry = $entries[0];
            if ( null !== $entry['unique_id'] ) {
                return;
            }
            $item_name = isset( $entry['suffix'] ) ? $this->kebab_to_camel_case( $entry['suffix'] ) : 'item';
            $result    = $this->evaluate( $entry );

            // Gets the content between the template tags and leaves the cursor in the closer tag.
            $inner_content = $p->get_content_between_balanced_template_tags();

            // Checks if there is a manual server-side directive processing.
            $template_end = 'data-wp-each: template end';
            $p->set_bookmark( $template_end );
            $p->next_tag();
            $manual_sdp = $p->get_attribute( 'data-wp-each-child' );
            $p->seek( $template_end ); // Rewinds to the template closer tag.
            $p->release_bookmark( $template_end );

            /*
             * It doesn't process in these situations:
             * - Manual server-side directive processing.
             * - Empty or non-array values.
             * - Associative arrays because those are deserialized as objects in JS.
             * - Templates that contain top-level texts because those texts can't be
             *   identified and removed in the client.
             */
            if (
                $manual_sdp ||
                empty( $result ) ||
                ! is_array( $result ) ||
                ! array_is_list( $result ) ||
                ! str_starts_with( trim( $inner_content ), '<' ) ||
                ! str_ends_with( trim( $inner_content ), '>' )
            ) {
                array_pop( $tag_stack );
                return;
            }

            // Processes the inner content for each item of the array.
            $processed_content = '';
            foreach ( $result as $item ) {
                // Creates a new context that includes the current item of the array.
                $this->context_stack[] = array_replace_recursive(
                    end( $this->context_stack ) !== false ? end( $this->context_stack ) : array(),
                    array( $entry['namespace'] => array( $item_name => $item ) )
                );

                // Processes the inner content with the new context.
                $processed_item = $this->_process_directives( $inner_content );

                if ( null === $processed_item ) {
                    // If the HTML is unbalanced, stop processing it.
                    array_pop( $this->context_stack );
                    return;
                }

                /*
                 * Adds the `data-wp-each-child` directive to each top-level tag
                 * rendered by this `data-wp-each` directive. The value is the
                 * `data-wp-each` directive's namespace and path.
                 *
                 * Nested `data-wp-each` directives could render
                 * `data-wp-each-child` elements at the top level as well, and
                 * they should be overwritten.
                 *
                 * @since 6.9.0
                 */
                $i = new WP_Interactivity_API_Directives_Processor( $processed_item );
                while ( $i->next_tag() ) {
                    $i->set_attribute( 'data-wp-each-child', $entry['namespace'] . '::' . $entry['value'] );
                    $i->next_balanced_tag_closer_tag();
                }
                $processed_content .= $i->get_updated_html();

                // Removes the current context from the stack.
                array_pop( $this->context_stack );
            }

            // Appends the processed content after the tag closer of the template.
            $p->append_content_after_template_tag_closer( $processed_content );

            // Pops the last tag because it skipped the closing tag of the template tag.
            array_pop( $tag_stack );
        }
    }
}