<?php

/**

 * Script Modules API: WP_Script_Modules class.

 *

 * Native support for ES Modules and Import Maps.

 *

 * @package WordPress

 * @subpackage Script Modules

 */

/**

 * Core class used to register script modules.

 *

 * @since 6.5.0

 */

class WP_Script_Modules {

	/**

	 * Holds the registered script modules, keyed by script module identifier.

	 *

	 * @since 6.5.0

	 * @var array[]

	 */

	private $registered = array();

	/**

	 * Holds the script module identifiers that were enqueued before registered.

	 *

	 * @since 6.5.0

	 * @var array<string, true>

	 */

	private $enqueued_before_registered = array();

	/**

	 * Registers the script module if no script module with that script module

	 * identifier has already been registered.

	 *

	 * @since 6.5.0

	 *

	 * @param string            $id       The identifier of the script module. Should be unique. It will be used in the

	 *                                    final import map.

	 * @param string            $src      Optional. Full URL of the script module, or path of the script module relative

	 *                                    to the WordPress root directory. If it is provided and the script module has

	 *                                    not been registered yet, it will be registered.

	 * @param array             $deps     {

	 *                                        Optional. List of dependencies.

	 *

	 *                                        @type string|array ...$0 {

	 *                                            An array of script module identifiers of the dependencies of this script

	 *                                            module. The dependencies can be strings or arrays. If they are arrays,

	 *                                            they need an `id` key with the script module identifier, and can contain

	 *                                            an `import` key with either `static` or `dynamic`. By default,

	 *                                            dependencies that don't contain an `import` key are considered static.

	 *

	 *                                            @type string $id     The script module identifier.

	 *                                            @type string $import Optional. Import type. May be either `static` or

	 *                                                                 `dynamic`. Defaults to `static`.

	 *                                        }

	 *                                    }

	 * @param string|false|null $version  Optional. String specifying the script module version number. Defaults to false.

	 *                                    It is added to the URL as a query string for cache busting purposes. If $version

	 *                                    is set to false, the version number is the currently installed WordPress version.

	 *                                    If $version is set to null, no version is added.

	 */

	public function register( string $id, string $src, array $deps = array(), $version = false ) {

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

			$dependencies = array();

			foreach ( $deps as $dependency ) {

				if ( is_array( $dependency ) ) {

					if ( ! isset( $dependency['id'] ) ) {

						_doing_it_wrong( __METHOD__, __( 'Missing required id key in entry among dependencies array.' ), '6.5.0' );

						continue;

					}

					$dependencies[] = array(

						'id'     => $dependency['id'],

						'import' => isset( $dependency['import'] ) && 'dynamic' === $dependency['import'] ? 'dynamic' : 'static',

					);

				} elseif ( is_string( $dependency ) ) {

					$dependencies[] = array(

						'id'     => $dependency,

						'import' => 'static',

					);

				} else {

					_doing_it_wrong( __METHOD__, __( 'Entries in dependencies array must be either strings or arrays with an id key.' ), '6.5.0' );

				}

			}

			$this->registered[ $id ] = array(

				'src'          => $src,

				'version'      => $version,

				'enqueue'      => isset( $this->enqueued_before_registered[ $id ] ),

				'dependencies' => $dependencies,

			);

		}

	}

	/**

	 * Marks the script module to be enqueued in the page.

	 *

	 * If a src is provided and the script module has not been registered yet, it

	 * will be registered.

	 *

	 * @since 6.5.0

	 *

	 * @param string            $id       The identifier of the script module. Should be unique. It will be used in the

	 *                                    final import map.

	 * @param string            $src      Optional. Full URL of the script module, or path of the script module relative

	 *                                    to the WordPress root directory. If it is provided and the script module has

	 *                                    not been registered yet, it will be registered.

	 * @param array             $deps     {

	 *                                        Optional. List of dependencies.

	 *

	 *                                        @type string|array ...$0 {

	 *                                            An array of script module identifiers of the dependencies of this script

	 *                                            module. The dependencies can be strings or arrays. If they are arrays,

	 *                                            they need an `id` key with the script module identifier, and can contain

	 *                                            an `import` key with either `static` or `dynamic`. By default,

	 *                                            dependencies that don't contain an `import` key are considered static.

	 *

	 *                                            @type string $id     The script module identifier.

	 *                                            @type string $import Optional. Import type. May be either `static` or

	 *                                                                 `dynamic`. Defaults to `static`.

	 *                                        }

	 *                                    }

	 * @param string|false|null $version  Optional. String specifying the script module version number. Defaults to false.

	 *                                    It is added to the URL as a query string for cache busting purposes. If $version

	 *                                    is set to false, the version number is the currently installed WordPress version.

	 *                                    If $version is set to null, no version is added.

	 */

	public function enqueue( string $id, string $src = '', array $deps = array(), $version = false ) {

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

			$this->registered[ $id ]['enqueue'] = true;

		} elseif ( $src ) {

			$this->register( $id, $src, $deps, $version );

			$this->registered[ $id ]['enqueue'] = true;

		} else {

			$this->enqueued_before_registered[ $id ] = true;

		}

	}

	/**

	 * Unmarks the script module so it will no longer be enqueued in the page.

	 *

	 * @since 6.5.0

	 *

	 * @param string $id The identifier of the script module.

	 */

	public function dequeue( string $id ) {

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

			$this->registered[ $id ]['enqueue'] = false;

		}

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

	}

	/**

	 * Removes a registered script module.

	 *

	 * @since 6.5.0

	 *

	 * @param string $id The identifier of the script module.

	 */

	public function deregister( string $id ) {

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

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

	}

	/**

	 * Adds the hooks to print the import map, enqueued script modules and script

	 * module preloads.

	 *

	 * In classic themes, the script modules used by the blocks are not yet known

	 * when the `wp_head` actions is fired, so it needs to print everything in the

	 * footer.

	 *

	 * @since 6.5.0

	 */

	public function add_hooks() {

		$position = wp_is_block_theme() ? 'wp_head' : 'wp_footer';

		add_action( $position, array( $this, 'print_import_map' ) );

		add_action( $position, array( $this, 'print_enqueued_script_modules' ) );

		add_action( $position, array( $this, 'print_script_module_preloads' ) );

		add_action( 'admin_print_footer_scripts', array( $this, 'print_import_map' ) );

		add_action( 'admin_print_footer_scripts', array( $this, 'print_enqueued_script_modules' ) );

		add_action( 'admin_print_footer_scripts', array( $this, 'print_script_module_preloads' ) );

	}

	/**

	 * Prints the enqueued script modules using script tags with type="module"

	 * attributes.

	 *

	 * @since 6.5.0

	 */

	public function print_enqueued_script_modules() {

		foreach ( $this->get_marked_for_enqueue() as $id => $script_module ) {

			wp_print_script_tag(

				array(

					'type' => 'module',

					'src'  => $this->get_src( $id ),

					'id'   => $id . '-js-module',

				)

			);

		}

	}

	/**

	 * Prints the the static dependencies of the enqueued script modules using

	 * link tags with rel="modulepreload" attributes.

	 *

	 * If a script module is marked for enqueue, it will not be preloaded.

	 *

	 * @since 6.5.0

	 */

	public function print_script_module_preloads() {

		foreach ( $this->get_dependencies( array_keys( $this->get_marked_for_enqueue() ), array( 'static' ) ) as $id => $script_module ) {

			// Don't preload if it's marked for enqueue.

			if ( true !== $script_module['enqueue'] ) {

				echo sprintf(

					'<link rel="modulepreload" href="%s" id="%s">',

					esc_url( $this->get_src( $id ) ),

					esc_attr( $id . '-js-modulepreload' )

				);

			}

		}

	}

	/**

	 * Prints the import map using a script tag with a type="importmap" attribute.

	 *

	 * @since 6.5.0

	 *

	 * @global WP_Scripts $wp_scripts The WP_Scripts object for printing the polyfill.

	 */

	public function print_import_map() {

		$import_map = $this->get_import_map();

		if ( ! empty( $import_map['imports'] ) ) {

			global $wp_scripts;

			if ( isset( $wp_scripts ) ) {

				wp_print_inline_script_tag(

					wp_get_script_polyfill(

						$wp_scripts,

						array(

							'HTMLScriptElement.supports && HTMLScriptElement.supports("importmap")' => 'wp-polyfill-importmap',

						)

					),

					array(

						'id' => 'wp-load-polyfill-importmap',

					)

				);

			}

			wp_print_inline_script_tag(

				wp_json_encode( $import_map, JSON_HEX_TAG | JSON_HEX_AMP ),

				array(

					'type' => 'importmap',

					'id'   => 'wp-importmap',

				)

			);

		}

	}

	/**

	 * Returns the import map array.

	 *

	 * @since 6.5.0

	 *

	 * @return array Array with an `imports` key mapping to an array of script module identifiers and their respective

	 *               URLs, including the version query.

	 */

	private function get_import_map(): array {

		$imports = array();

		foreach ( $this->get_dependencies( array_keys( $this->get_marked_for_enqueue() ) ) as $id => $script_module ) {

			$imports[ $id ] = $this->get_src( $id );

		}

		return array( 'imports' => $imports );

	}

	/**

	 * Retrieves the list of script modules marked for enqueue.

	 *

	 * @since 6.5.0

	 *

	 * @return array[] Script modules marked for enqueue, keyed by script module identifier.

	 */

	private function get_marked_for_enqueue(): array {

		$enqueued = array();

		foreach ( $this->registered as $id => $script_module ) {

			if ( true === $script_module['enqueue'] ) {

				$enqueued[ $id ] = $script_module;

			}

		}

		return $enqueued;

	}

	/**

	 * Retrieves all the dependencies for the given script module identifiers,

	 * filtered by import types.

	 *

	 * It will consolidate an array containing a set of unique dependencies based

	 * on the requested import types: 'static', 'dynamic', or both. This method is

	 * recursive and also retrieves dependencies of the dependencies.

	 *

	 * @since 6.5.0

	 *

	 * @param string[] $ids          The identifiers of the script modules for which to gather dependencies.

	 * @param string[] $import_types Optional. Import types of dependencies to retrieve: 'static', 'dynamic', or both.

	 *                               Default is both.

	 * @return array[] List of dependencies, keyed by script module identifier.

	 */

	private function get_dependencies( array $ids, array $import_types = array( 'static', 'dynamic' ) ) {

		return array_reduce(

			$ids,

			function ( $dependency_script_modules, $id ) use ( $import_types ) {

				$dependencies = array();

				foreach ( $this->registered[ $id ]['dependencies'] as $dependency ) {

					if (

					in_array( $dependency['import'], $import_types, true ) &&

					isset( $this->registered[ $dependency['id'] ] ) &&

					! isset( $dependency_script_modules[ $dependency['id'] ] )

					) {

						$dependencies[ $dependency['id'] ] = $this->registered[ $dependency['id'] ];

					}

				}

				return array_merge( $dependency_script_modules, $dependencies, $this->get_dependencies( array_keys( $dependencies ), $import_types ) );

			},

			array()

		);

	}

	/**

	 * Gets the versioned URL for a script module src.

	 *

	 * If $version is set to false, the version number is the currently installed

	 * WordPress version. If $version is set to null, no version is added.

	 * Otherwise, the string passed in $version is used.

	 *

	 * @since 6.5.0

	 *

	 * @param string $id The script module identifier.

	 * @return string The script module src with a version if relevant.

	 */

	private function get_src( string $id ): string {

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

			return '';

		}

		$script_module = $this->registered[ $id ];

		$src           = $script_module['src'];

		if ( false === $script_module['version'] ) {

			$src = add_query_arg( 'ver', get_bloginfo( 'version' ), $src );

		} elseif ( null !== $script_module['version'] ) {

			$src = add_query_arg( 'ver', $script_module['version'], $src );

		}

		/**

		 * Filters the script module source.

		 *

		 * @since 6.5.0

		 *

		 * @param string $src Module source URL.

		 * @param string $id  Module identifier.

		 */

		$src = apply_filters( 'script_module_loader_src', $src, $id );

		return $src;

	}

}