<?php
/**
 * Blocks API: WP_Block class
 *
 * @package WordPress
 * @since 5.5.0
 */

/**
 * Class representing a parsed instance of a block.
 *
 * @since 5.5.0
 * @property array $attributes
 */
#[AllowDynamicProperties]
class WP_Block {

	/**
	 * Original parsed array representation of block.
	 *
	 * @since 5.5.0
	 * @var array
	 */
	public $parsed_block;

	/**
	 * Name of block.
	 *
	 * @example "core/paragraph"
	 *
	 * @since 5.5.0
	 * @var string|null
	 */
	public $name;

	/**
	 * Block type associated with the instance.
	 *
	 * @since 5.5.0
	 * @var WP_Block_Type
	 */
	public $block_type;

	/**
	 * Block context values.
	 *
	 * @since 5.5.0
	 * @var array
	 */
	public $context = array();

	/**
	 * All available context of the current hierarchy.
	 *
	 * @since 5.5.0
	 * @var array
	 */
	protected $available_context = array();

	/**
	 * Block type registry.
	 *
	 * @since 5.9.0
	 * @var WP_Block_Type_Registry
	 */
	protected $registry;

	/**
	 * List of inner blocks (of this same class)
	 *
	 * @since 5.5.0
	 * @var WP_Block_List
	 */
	public $inner_blocks = array();

	/**
	 * Resultant HTML from inside block comment delimiters after removing inner
	 * blocks.
	 *
	 * @example "...Just <!-- wp:test /--> testing..." -> "Just testing..."
	 *
	 * @since 5.5.0
	 * @var string
	 */
	public $inner_html = '';

	/**
	 * List of string fragments and null markers where inner blocks were found
	 *
	 * @example array(
	 *   'inner_html'    => 'BeforeInnerAfter',
	 *   'inner_blocks'  => array( block, block ),
	 *   'inner_content' => array( 'Before', null, 'Inner', null, 'After' ),
	 * )
	 *
	 * @since 5.5.0
	 * @var array
	 */
	public $inner_content = array();

	/**
	 * Constructor.
	 *
	 * Populates object properties from the provided block instance argument.
	 *
	 * The given array of context values will not necessarily be available on
	 * the instance itself, but is treated as the full set of values provided by
	 * the block's ancestry. This is assigned to the private `available_context`
	 * property. Only values which are configured to consumed by the block via
	 * its registered type will be assigned to the block's `context` property.
	 *
	 * @since 5.5.0
	 *
	 * @param array                  $block             {
	 *     An associative array of a single parsed block object. See WP_Block_Parser_Block.
	 *
	 *     @type string|null $blockName    Name of block.
	 *     @type array       $attrs        Attributes from block comment delimiters.
	 *     @type array       $innerBlocks  List of inner blocks. An array of arrays that
	 *                                     have the same structure as this one.
	 *     @type string      $innerHTML    HTML from inside block comment delimiters.
	 *     @type array       $innerContent List of string fragments and null markers where inner blocks were found.
	 * }
	 * @param array                  $available_context Optional array of ancestry context values.
	 * @param WP_Block_Type_Registry $registry          Optional block type registry.
	 */
	public function __construct( $block, $available_context = array(), $registry = null ) {
		$this->parsed_block = $block;
		$this->name         = $block['blockName'];

		if ( is_null( $registry ) ) {
			$registry = WP_Block_Type_Registry::get_instance();
		}

		$this->registry = $registry;

		$this->block_type = $registry->get_registered( $this->name );

		$this->available_context = $available_context;

		$this->refresh_context_dependents();
	}

	/**
	 * Updates the context for the current block and its inner blocks.
	 *
	 * The method updates the context of inner blocks, if any, by passing down
	 * any context values the block provides (`provides_context`).
	 *
	 * If the block has inner blocks, the method recursively processes them by creating new instances of `WP_Block`
	 * for each inner block and updating their context based on the block's `provides_context` property.
	 *
	 * @since 6.8.0
	 */
	public function refresh_context_dependents() {
		/*
		 * Merging the `$context` property here is not ideal, but for now needs to happen because of backward compatibility.
		 * Ideally, the `$context` property itself would not be filterable directly and only the `$available_context` would be filterable.
		 * However, this needs to be separately explored whether it's possible without breakage.
		 */
		$this->available_context = array_merge( $this->available_context, $this->context );

		if ( ! empty( $this->block_type->uses_context ) ) {
			foreach ( $this->block_type->uses_context as $context_name ) {
				if ( array_key_exists( $context_name, $this->available_context ) ) {
					$this->context[ $context_name ] = $this->available_context[ $context_name ];
				}
			}
		}

		$this->refresh_parsed_block_dependents();
	}

	/**
	 * Updates the parsed block content for the current block and its inner blocks.
	 *
	 * This method sets the `inner_html` and `inner_content` properties of the block based on the parsed
	 * block content provided during initialization. It ensures that the block instance reflects the
	 * most up-to-date content for both the inner HTML and any string fragments around inner blocks.
	 *
	 * If the block has inner blocks, this method initializes a new `WP_Block_List` for them, ensuring the
	 * correct content and context are updated for each nested block.
	 *
	 * @since 6.8.0
	 */
	public function refresh_parsed_block_dependents() {
		if ( ! empty( $this->parsed_block['innerBlocks'] ) ) {
			$child_context = $this->available_context;

			if ( ! empty( $this->block_type->provides_context ) ) {
				foreach ( $this->block_type->provides_context as $context_name => $attribute_name ) {
					if ( array_key_exists( $attribute_name, $this->attributes ) ) {
						$child_context[ $context_name ] = $this->attributes[ $attribute_name ];
					}
				}
			}

			$this->inner_blocks = new WP_Block_List( $this->parsed_block['innerBlocks'], $child_context, $this->registry );
		}

		if ( ! empty( $this->parsed_block['innerHTML'] ) ) {
			$this->inner_html = $this->parsed_block['innerHTML'];
		}

		if ( ! empty( $this->parsed_block['innerContent'] ) ) {
			$this->inner_content = $this->parsed_block['innerContent'];
		}
	}

	/**
	 * Returns a value from an inaccessible property.
	 *
	 * This is used to lazily initialize the `attributes` property of a block,
	 * such that it is only prepared with default attributes at the time that
	 * the property is accessed. For all other inaccessible properties, a `null`
	 * value is returned.
	 *
	 * @since 5.5.0
	 *
	 * @param string $name Property name.
	 * @return array|null Prepared attributes, or null.
	 */
	public function __get( $name ) {
		if ( 'attributes' === $name ) {
			$this->attributes = $this->parsed_block['attrs'] ??
				array();

			if ( ! is_null( $this->block_type ) ) {
				$this->attributes = $this->block_type->prepare_attributes_for_render( $this->attributes );
			}

			return $this->attributes;
		}

		return null;
	}

	/**
	 * Processes the block bindings and updates the block attributes with the values from the sources.
	 *
	 * A block might contain bindings in its attributes. Bindings are mappings
	 * between an attribute of the block and a source. A "source" is a function
	 * registered with `register_block_bindings_source()` that defines how to
	 * retrieve a value from outside the block, e.g. from post meta.
	 *
	 * This function will process those bindings and update the block's attributes
	 * with the values coming from the bindings.
	 *
	 * ### Example
	 *
	 * The "bindings" property for an Image block might look like this:
	 *
	 * ```json
	 * {
	 *   "metadata": {
	 *     "bindings": {
	 *       "title": {
	 *         "source": "core/post-meta",
	 *         "args": { "key": "text_custom_field" }
	 *       },
	 *       "url": {
	 *         "source": "core/post-meta",
	 *         "args": { "key": "url_custom_field" }
	 *       }
	 *     }
	 *   }
	 * }
	 * ```
	 *
	 * The above example will replace the `title` and `url` attributes of the Image
	 * block with the values of the `text_custom_field` and `url_custom_field` post meta.
	 *
	 * @since 6.5.0
	 * @since 6.6.0 Handle the `__default` attribute for pattern overrides.
	 * @since 6.7.0 Return any updated bindings metadata in the computed attributes.
	 *
	 * @return array The computed block attributes for the provided block bindings.
	 */
	private function process_block_bindings() {
		$block_type                 = $this->name;
		$parsed_block               = $this->parsed_block;
		$computed_attributes        = array();
		$supported_block_attributes = get_block_bindings_supported_attributes( $block_type );

		// If the block doesn't have the bindings property, isn't one of the supported
		// block types, or the bindings property is not an array, return the block content.
		if (
			empty( $supported_block_attributes ) ||
			empty( $parsed_block['attrs']['metadata']['bindings'] ) ||
			! is_array( $parsed_block['attrs']['metadata']['bindings'] )
		) {
			return $computed_attributes;
		}

		$bindings = $parsed_block['attrs']['metadata']['bindings'];

		/*
		 * If the default binding is set for pattern overrides, replace it
		 * with a pattern override binding for all supported attributes.
		 */
		if (
			isset( $bindings['__default']['source'] ) &&
			'core/pattern-overrides' === $bindings['__default']['source']
		) {
			$updated_bindings = array();

			/*
			 * Build a binding array of all supported attributes.
			 * Note that this also omits the `__default` attribute from the
			 * resulting array.
			 */
			foreach ( $supported_block_attributes as $attribute_name ) {
				// Retain any non-pattern override bindings that might be present.
				$updated_bindings[ $attribute_name ] = $bindings[ $attribute_name ] ?? array( 'source' => 'core/pattern-overrides' );
			}
			$bindings = $updated_bindings;
			/*
			 * Update the bindings metadata of the computed attributes.
			 * This ensures the block receives the expanded __default binding metadata when it renders.
			 */
			$computed_attributes['metadata'] = array_merge(
				$parsed_block['attrs']['metadata'],
				array( 'bindings' => $bindings )
			);
		}

		foreach ( $bindings as $attribute_name => $block_binding ) {
			// If the attribute is not in the supported list, process next attribute.
			if ( ! in_array( $attribute_name, $supported_block_attributes, true ) ) {
				continue;
			}
			// If no source is provided, or that source is not registered, process next attribute.
			if ( ! isset( $block_binding['source'] ) || ! is_string( $block_binding['source'] ) ) {
				continue;
			}

			$block_binding_source = get_block_bindings_source( $block_binding['source'] );
			if ( null === $block_binding_source ) {
				continue;
			}

			// Adds the necessary context defined by the source.
			if ( ! empty( $block_binding_source->uses_context ) ) {
				foreach ( $block_binding_source->uses_context as $context_name ) {
					if ( array_key_exists( $context_name, $this->available_context ) ) {
						$this->context[ $context_name ] = $this->available_context[ $context_name ];
					}
				}
			}

			$source_args  = ! empty( $block_binding['args'] ) && is_array( $block_binding['args'] ) ? $block_binding['args'] : array();
			$source_value = $block_binding_source->get_value( $source_args, $this, $attribute_name );

			// If the value is not null, process the HTML based on the block and the attribute.
			if ( ! is_null( $source_value ) ) {
				$computed_attributes[ $attribute_name ] = $source_value;
			}
		}

		return $computed_attributes;
	}

	/**
	 * Depending on the block attribute name, replace its value in the HTML based on the value provided.
	 *
	 * @since 6.5.0
	 *
	 * @param string $block_content  Block content.
	 * @param string $attribute_name The attribute name to replace.
	 * @param mixed  $source_value   The value used to replace in the HTML.
	 * @return string The modified block content.
	 */
	private function replace_html( string $block_content, string $attribute_name, $source_value ) {
		$block_type = $this->block_type;
		if ( ! isset( $block_type->attributes[ $attribute_name ]['source'] ) ) {
			return $block_content;
		}

		// Depending on the attribute source, the processing will be different.
		switch ( $block_type->attributes[ $attribute_name ]['source'] ) {
			case 'html':
			case 'rich-text':
				$block_reader = self::get_block_bindings_processor( $block_content );

				// TODO: Support for CSS selectors whenever they are ready in the HTML API.
				// In the meantime, support comma-separated selectors by exploding them into an array.
				$selectors = explode( ',', $block_type->attributes[ $attribute_name ]['selector'] );
				// Add a bookmark to the first tag to be able to iterate over the selectors.
				$block_reader->next_tag();
				$block_reader->set_bookmark( 'iterate-selectors' );

				foreach ( $selectors as $selector ) {
					// If the parent tag, or any of its children, matches the selector, replace the HTML.
					if ( strcasecmp( $block_reader->get_tag(), $selector ) === 0 || $block_reader->next_tag(
						array(
							'tag_name' => $selector,
						)
					) ) {
						// TODO: Use `WP_HTML_Processor::set_inner_html` method once it's available.
						$block_reader->release_bookmark( 'iterate-selectors' );
						$block_reader->replace_rich_text( wp_kses_post( $source_value ) );
						return $block_reader->get_updated_html();
					} else {
						$block_reader->seek( 'iterate-selectors' );
					}
				}
				$block_reader->release_bookmark( 'iterate-selectors' );
				return $block_content;

			case 'attribute':
				$amended_content = new WP_HTML_Tag_Processor( $block_content );
				if ( ! $amended_content->next_tag(
					array(
						// TODO: build the query from CSS selector.
						'tag_name' => $block_type->attributes[ $attribute_name ]['selector'],
					)
				) ) {
					return $block_content;
				}
				$amended_content->set_attribute( $block_type->attributes[ $attribute_name ]['attribute'], $source_value );
				return $amended_content->get_updated_html();

			default:
				return $block_content;
		}
	}

	private static function get_block_bindings_processor( string $block_content ) {
		$internal_processor_class = new class('', WP_HTML_Processor::CONSTRUCTOR_UNLOCK_CODE) extends WP_HTML_Processor {
			/**
			 * Replace the rich text content between a tag opener and matching closer.
			 *
			 * When stopped on a tag opener, replace the content enclosed by it and its
			 * matching closer with the provided rich text.
			 *
			 * @param string $rich_text The rich text to replace the original content with.
			 * @return bool True on success.
			 */
			public function replace_rich_text( $rich_text ) {
				if ( $this->is_tag_closer() || ! $this->expects_closer() ) {
					return false;
				}

				$depth    = $this->get_current_depth();
				$tag_name = $this->get_tag();

				$this->set_bookmark( '_wp_block_bindings' );
				// The bookmark names are prefixed with `_` so the key below has an extra `_`.
				$tag_opener = $this->bookmarks['__wp_block_bindings'];
				$start      = $tag_opener->start + $tag_opener->length;

				// Find matching tag closer.
				while ( $this->next_token() && $this->get_current_depth() >= $depth ) {
				}

				if ( ! $this->is_tag_closer() || $tag_name !== $this->get_tag() ) {
					return false;
				}

				$this->set_bookmark( '_wp_block_bindings' );
				$tag_closer = $this->bookmarks['__wp_block_bindings'];
				$end        = $tag_closer->start;

				$this->lexical_updates[] = new WP_HTML_Text_Replacement(
					$start,
					$end - $start,
					$rich_text
				);

				return true;
			}
		};

		return $internal_processor_class::create_fragment( $block_content );
	}

	/**
	 * Generates the render output for the block.
	 *
	 * @since 5.5.0
	 * @since 6.5.0 Added block bindings processing.
	 *
	 * @global WP_Post $post Global post object.
	 *
	 * @param array $options {
	 *     Optional options object.
	 *
	 *     @type bool $dynamic Defaults to 'true'. Optionally set to false to avoid using the block's render_callback.
	 * }
	 * @return string Rendered block output.
	 */
	public function render( $options = array() ) {
		global $post;

		$before_wp_enqueue_scripts_count = did_action( 'wp_enqueue_scripts' );

		// Capture the current assets queues.
		$before_styles_queue         = wp_styles()->queue;
		$before_scripts_queue        = wp_scripts()->queue;
		$before_script_modules_queue = wp_script_modules()->get_queue();

		/*
		 * There can be only one root interactive block at a time because the rendered HTML of that block contains
		 * the rendered HTML of all its inner blocks, including any interactive block.
		 */
		static $root_interactive_block = null;
		/**
		 * Filters whether Interactivity API should process directives.
		 *
		 * @since 6.6.0
		 *
		 * @param bool $enabled Whether the directives processing is enabled.
		 */
		$interactivity_process_directives_enabled = apply_filters( 'interactivity_process_directives', true );
		if (
			$interactivity_process_directives_enabled && null === $root_interactive_block && (
				( isset( $this->block_type->supports['interactivity'] ) && true === $this->block_type->supports['interactivity'] ) ||
				! empty( $this->block_type->supports['interactivity']['interactive'] )
			)
		) {
			$root_interactive_block = $this;
		}

		$options = wp_parse_args(
			$options,
			array(
				'dynamic' => true,
			)
		);

		// Process the block bindings and get attributes updated with the values from the sources.
		$computed_attributes = $this->process_block_bindings();
		if ( ! empty( $computed_attributes ) ) {
			// Merge the computed attributes with the original attributes.
			$this->attributes = array_merge( $this->attributes, $computed_attributes );
		}

		$is_dynamic    = $options['dynamic'] && $this->name && null !== $this->block_type && $this->block_type->is_dynamic();
		$block_content = '';

		if ( ! $options['dynamic'] || empty( $this->block_type->skip_inner_blocks ) ) {
			$index = 0;

			foreach ( $this->inner_content as $chunk ) {
				if ( is_string( $chunk ) ) {
					$block_content .= $chunk;
				} else {
					$inner_block  = $this->inner_blocks[ $index ];
					$parent_block = $this;

					/** This filter is documented in wp-includes/blocks.php */
					$pre_render = apply_filters( 'pre_render_block', null, $inner_block->parsed_block, $parent_block );

					if ( ! is_null( $pre_render ) ) {
						$block_content .= $pre_render;
					} else {
						$source_block        = $inner_block->parsed_block;
						$inner_block_context = $inner_block->context;

						/** This filter is documented in wp-includes/blocks.php */
						$inner_block->parsed_block = apply_filters( 'render_block_data', $inner_block->parsed_block, $source_block, $parent_block );

						/** This filter is documented in wp-includes/blocks.php */
						$inner_block->context = apply_filters( 'render_block_context', $inner_block->context, $inner_block->parsed_block, $parent_block );

						/*
						 * The `refresh_context_dependents()` method already calls `refresh_parsed_block_dependents()`.
						 * Therefore the second condition is irrelevant if the first one is satisfied.
						 */
						if ( $inner_block->context !== $inner_block_context ) {
							$inner_block->refresh_context_dependents();
						} elseif ( $inner_block->parsed_block !== $source_block ) {
							$inner_block->refresh_parsed_block_dependents();
						}

						$block_content .= $inner_block->render();
					}

					++$index;
				}
			}
		}

		if ( ! empty( $computed_attributes ) && ! empty( $block_content ) ) {
			foreach ( $computed_attributes as $attribute_name => $source_value ) {
				$block_content = $this->replace_html( $block_content, $attribute_name, $source_value );
			}
		}

		if ( $is_dynamic ) {
			$global_post = $post;
			$parent      = WP_Block_Supports::$block_to_render;

			WP_Block_Supports::$block_to_render = $this->parsed_block;

			$block_content = (string) call_user_func( $this->block_type->render_callback, $this->attributes, $block_content, $this );

			WP_Block_Supports::$block_to_render = $parent;

			$post = $global_post;
		}

		if ( ( ! empty( $this->block_type->script_handles ) ) ) {
			foreach ( $this->block_type->script_handles as $script_handle ) {
				wp_enqueue_script( $script_handle );
			}
		}

		if ( ! empty( $this->block_type->view_script_handles ) ) {
			foreach ( $this->block_type->view_script_handles as $view_script_handle ) {
				wp_enqueue_script( $view_script_handle );
			}
		}

		if ( ! empty( $this->block_type->view_script_module_ids ) ) {
			foreach ( $this->block_type->view_script_module_ids as $view_script_module_id ) {
				wp_enqueue_script_module( $view_script_module_id );
			}
		}

		/*
		 * For Core blocks, these styles are only enqueued if `wp_should_load_separate_core_block_assets()` returns
		 * true. Otherwise these `wp_enqueue_style()` calls will not have any effect, as the Core blocks are relying on
		 * the combined 'wp-block-library' stylesheet instead, which is unconditionally enqueued.
		 */
		if ( ( ! empty( $this->block_type->style_handles ) ) ) {
			foreach ( $this->block_type->style_handles as $style_handle ) {
				wp_enqueue_style( $style_handle );
			}
		}

		if ( ( ! empty( $this->block_type->view_style_handles ) ) ) {
			foreach ( $this->block_type->view_style_handles as $view_style_handle ) {
				wp_enqueue_style( $view_style_handle );
			}
		}

		/**
		 * Filters the content of a single block.
		 *
		 * @since 5.0.0
		 * @since 5.9.0 The `$instance` parameter was added.
		 *
		 * @param string   $block_content The block content.
		 * @param array    $block         The full block, including name and attributes.
		 * @param WP_Block $instance      The block instance.
		 */
		$block_content = apply_filters( 'render_block', $block_content, $this->parsed_block, $this );

		/**
		 * Filters the content of a single block.
		 *
		 * The dynamic portion of the hook name, `$name`, refers to
		 * the block name, e.g. "core/paragraph".
		 *
		 * @since 5.7.0
		 * @since 5.9.0 The `$instance` parameter was added.
		 *
		 * @param string   $block_content The block content.
		 * @param array    $block         The full block, including name and attributes.
		 * @param WP_Block $instance      The block instance.
		 */
		$block_content = apply_filters( "render_block_{$this->name}", $block_content, $this->parsed_block, $this );

		if ( $root_interactive_block === $this ) {
			// The root interactive block has finished rendering. Time to process directives.
			$block_content          = wp_interactivity_process_directives( $block_content );
			$root_interactive_block = null;
		}

		// Capture the new assets enqueued during rendering, and restore the queues the state prior to rendering.
		$after_styles_queue         = wp_styles()->queue;
		$after_scripts_queue        = wp_scripts()->queue;
		$after_script_modules_queue = wp_script_modules()->get_queue();

		/*
		 * As a very special case, a dynamic block may in fact include a call to wp_head() (and thus wp_enqueue_scripts()),
		 * in which all of its enqueued assets are targeting wp_footer. In this case, nothing would be printed, but this
		 * shouldn't indicate that the just-enqueued assets should be dequeued due to it being an empty block.
		 */
		$just_did_wp_enqueue_scripts = ( did_action( 'wp_enqueue_scripts' ) !== $before_wp_enqueue_scripts_count );

		$has_new_styles         = ( $before_styles_queue !== $after_styles_queue );
		$has_new_scripts        = ( $before_scripts_queue !== $after_scripts_queue );
		$has_new_script_modules = ( $before_script_modules_queue !== $after_script_modules_queue );

		// Dequeue the newly enqueued assets with the existing assets if the rendered block was empty & wp_enqueue_scripts did not fire.
		if (
			! $just_did_wp_enqueue_scripts &&
			( $has_new_styles || $has_new_scripts || $has_new_script_modules ) &&
			(
				trim( $block_content ) === '' &&
				/**
				 * Filters whether to enqueue assets for a block which has no rendered content.
				 *
				 * @since 6.9.0
				 *
				 * @param bool   $enqueue    Whether to enqueue assets.
				 * @param string $block_name Block name.
				 */
				! (bool) apply_filters( 'enqueue_empty_block_content_assets', false, $this->name )
			)
		) {
			foreach ( array_diff( $after_styles_queue, $before_styles_queue ) as $handle ) {
				wp_dequeue_style( $handle );
			}
			foreach ( array_diff( $after_scripts_queue, $before_scripts_queue ) as $handle ) {
				wp_dequeue_script( $handle );
			}
			foreach ( array_diff( $after_script_modules_queue, $before_script_modules_queue ) as $handle ) {
				wp_dequeue_script_module( $handle );
			}
		}

		return $block_content;
	}
}
