Migrate Block Patterns Registration to jetpack-mu-wpcom (#34162)

Co-authored-by: Miguel <miguel.san.segundo@automattic.com>

Committed via a GitHub action: https://github.com/Automattic/jetpack/actions/runs/6977731794

vendor/automattic/jetpack-mu-wpcom/CHANGELOG.md

@@ -11,6 +11,7 @@ This is an alpha version! The changes listed here are not final.
 
 ### Added
 - Add dynamic titles to task lists
+- Migrate Block Patterns
 
 ### Changed
 - Code Modernization: Replace usage of strpos() with str_contains()

vendor/automattic/jetpack-mu-wpcom/src/class-jetpack-mu-wpcom.php

@@ -66,6 +66,8 @@ public static function load_features() {
 		require_once __DIR__ . '/features/100-year-plan/locked-mode.php';
 
 		require_once __DIR__ . '/features/media/heif-support.php';
+
+		require_once __DIR__ . '/features/block-patterns/block-patterns.php';
 	}
 
 	/**

vendor/automattic/jetpack-mu-wpcom/src/features/block-patterns/README.md

@@ -0,0 +1,13 @@
+# Block Patterns
+
+## Adding a new pattern
+
+Please add any new block pattern to the `patterns` folder within this module.
+Every file in that folder gets automatically included registered as a block pattern.
+
+There are two ways to add a new pattern, depending on whether it contains text or images that need to be localized:
+
+1. A json file for static block patterns.
+1. A php file for dynamic block patterns that need localization.
+
+Please refer the Image and Description pattern as an example for a dynamic pattern that needs translation.

vendor/automattic/jetpack-mu-wpcom/src/features/block-patterns/block-patterns.php

@@ -0,0 +1,77 @@
+<?php
+/**
+ * Load block patterns from the API.
+ *
+ * @package automattic/jetpack-mu-wpcom
+ */
+
+/**
+ * Re-register some core patterns to push them down in the inserter list.
+ * The reason is that Dotcom curate the pattern list based on their look.
+ */
+function wpcom_reorder_curated_core_patterns() {
+	$pattern_names = array( 'core/social-links-shared-background-color' );
+	foreach ( $pattern_names as $pattern_name ) {
+		$pattern = \WP_Block_Patterns_Registry::get_instance()->get_registered( $pattern_name );
+		if ( $pattern ) {
+			unregister_block_pattern( $pattern_name );
+			register_block_pattern(
+				$pattern_name,
+				$pattern
+			);
+		}
+	}
+}
+
+/**
+ * Return a function that loads and register block patterns from the API. This
+ * function can be registered to the `rest_dispatch_request` filter.
+ *
+ * @param Function $register_patterns_func A function that when called will
+ * register the relevant block patterns in the registry.
+ */
+function register_patterns_on_api_request( $register_patterns_func ) {
+	/**
+	 * Load editing toolkit block patterns from the API.
+	 *
+	 * It will only register the patterns for certain allowed requests and
+	 * return early otherwise.
+	 *
+	 * @param mixed           $response
+	 * @param WP_REST_Request $request
+	 */
+	return function ( $response, $request ) use ( $register_patterns_func ) {
+		/**
+		 * Do nothing if it is loaded in the ETK.
+		 */
+		if ( class_exists( 'A8C\FSE\Block_Patterns_From_API' ) ) {
+			return $response;
+		}
+
+		$route = $request->get_route();
+		// Matches either /wp/v2/sites/123/block-patterns/patterns or /wp/v2/block-patterns/patterns
+		// to handle the API format of both WordPress.com and WordPress core.
+		$request_allowed = preg_match( '/^\/wp\/v2\/(sites\/[0-9]+\/)?block\-patterns\/(patterns|categories)$/', $route );
+
+		if ( ! $request_allowed || ! apply_filters( 'a8c_enable_block_patterns_api', false ) ) {
+			return $response;
+		}
+
+		$register_patterns_func();
+
+		wpcom_reorder_curated_core_patterns();
+
+		return $response;
+	};
+}
+add_filter(
+	'rest_dispatch_request',
+	register_patterns_on_api_request(
+		function () {
+			require_once __DIR__ . '/class-wpcom-block-patterns-from-api.php';
+			( new Wpcom_Block_Patterns_From_Api() )->register_patterns();
+		}
+	),
+	11,
+	2
+);