From 5a28a68c29a34c1200b5202fb0ac2c0f1f421c24 Mon Sep 17 00:00:00 2001
From: ashfame <mail@ashfame.com>
Date: Fri, 27 Dec 2024 11:06:34 +0400
Subject: [PATCH 1/8] change TransformersRegistry class to
 Transformers_Registry

---
 src/plugin/class-engine.php                                   | 2 +-
 src/plugin/class-subjects-controller.php                      | 4 ++--
 ...ansformersregistry.php => class-transformers-registry.php} | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)
 rename src/plugin/{class-transformersregistry.php => class-transformers-registry.php} (99%)

diff --git a/src/plugin/class-engine.php b/src/plugin/class-engine.php
index e8ae2d62..75359d61 100644
--- a/src/plugin/class-engine.php
+++ b/src/plugin/class-engine.php
@@ -9,7 +9,7 @@ class Engine {
 	public function __construct() {
 		require 'enum-subject-type.php';
 
-		require 'class-transformersregistry.php';
+		require 'class-transformers-registry.php';
 		require 'class-post-type-ui.php';
 		require 'class-transformer.php';
 		require 'class-subjects-controller.php';
diff --git a/src/plugin/class-subjects-controller.php b/src/plugin/class-subjects-controller.php
index 636d9e25..a80084f9 100644
--- a/src/plugin/class-subjects-controller.php
+++ b/src/plugin/class-subjects-controller.php
@@ -292,7 +292,7 @@ public function create_item( $request ): WP_REST_Response|WP_Error {
 		update_post_meta( $item['ID'], 'subject_type', $subject_type->value );
 
 		try {
-			TransformersRegistry::handle( $subject_type, Subject::from_post( $item['ID'] ) );
+			Transformers_Registry::handle( $subject_type, Subject::from_post( $item['ID'] ) );
 		} catch ( Exception $e ) {
 			return new WP_Error( $e->getCode(), $e->getMessage() );
 		}
@@ -322,7 +322,7 @@ public function update_item( $request ): WP_REST_Response|WP_Error {
 		$subject_type = $this->get_subject_type( $request );
 
 		try {
-			TransformersRegistry::handle( $subject_type, Subject::from_post( $item['ID'] ) );
+			Transformers_Registry::handle( $subject_type, Subject::from_post( $item['ID'] ) );
 		} catch ( Exception $e ) {
 			return new WP_Error( $e->getCode(), $e->getMessage() );
 		}
diff --git a/src/plugin/class-transformersregistry.php b/src/plugin/class-transformers-registry.php
similarity index 99%
rename from src/plugin/class-transformersregistry.php
rename to src/plugin/class-transformers-registry.php
index e2c22471..49fe442d 100644
--- a/src/plugin/class-transformersregistry.php
+++ b/src/plugin/class-transformers-registry.php
@@ -5,7 +5,7 @@
 use Exception;
 use InvalidArgumentException;
 
-class TransformersRegistry {
+class Transformers_Registry {
 	private static string $user_choice_meta_key_prefix = '_data_liberation_chosen_handler_';
 	private static array $handlers                     = array();
 

From b29316c12e42c5880455675a076e8759f2921ad9 Mon Sep 17 00:00:00 2001
From: ashfame <mail@ashfame.com>
Date: Fri, 27 Dec 2024 12:41:05 +0400
Subject: [PATCH 2/8] design the Ops class as per the desired interface for
 integration

---
 src/plugin/class-engine.php |  3 ++
 src/plugin/class-ops.php    | 65 +++++++++++++++++++++++++++++++++++++
 2 files changed, 68 insertions(+)
 create mode 100644 src/plugin/class-ops.php

diff --git a/src/plugin/class-engine.php b/src/plugin/class-engine.php
index 75359d61..be88660c 100644
--- a/src/plugin/class-engine.php
+++ b/src/plugin/class-engine.php
@@ -17,6 +17,7 @@ public function __construct() {
 		require 'class-schema.php';
 		require 'utils.php';
 		require 'class-subject.php';
+		require 'class-ops.php';
 
 		( function () {
 			new Transformer();
@@ -26,6 +27,8 @@ public function __construct() {
 			new Subjects_Controller( self::STORAGE_POST_TYPE );
 
 			new Storage( self::STORAGE_POST_TYPE );
+
+			Ops::init( self::STORAGE_POST_TYPE );
 		} )();
 	}
 }
diff --git a/src/plugin/class-ops.php b/src/plugin/class-ops.php
new file mode 100644
index 00000000..cd888a98
--- /dev/null
+++ b/src/plugin/class-ops.php
@@ -0,0 +1,65 @@
+<?php
+
+namespace DotOrg\TryWordPress;
+
+use WP_Post;
+
+class Ops {
+	private static string $post_type;
+
+	public static function init( string $post_type ): void {
+		static::$post_type = $post_type;
+	}
+
+	/**
+	 * Register your handler for the specified subject type
+	 *
+	 * @param SubjectType $subject_type Type of subject.
+	 * @param array       $identifier Array containing unique slug and description.
+	 * @param callable    $handler Function that would handle the transformation of subject for the specific subject type.
+	 * @return void
+	 */
+	public static function handle( SubjectType $subject_type, array $identifier, callable $handler ): void {
+		Handlers_Registry::add( $subject_type, $identifier, $handler );
+	}
+
+	/**
+	 * Register your handler for the specified subject type to just observe (read-only) data
+	 *
+	 * @param SubjectType $subject_type Type of subject.
+	 * @param array       $identifier Array containing unique slug and description.
+	 * @param callable    $handler Function that would handle the transformation of subject for the specific subject type.
+	 * @return void
+	 */
+	public static function observe( SubjectType $subject_type, array $identifier, callable $handler ): void {
+		Observers_Registry::add( $subject_type, $identifier, $handler );
+	}
+
+	/**
+	 * Loops over all liberated_post posts for the specified subject_type
+	 *
+	 * @TODO: pagination support
+	 *
+	 * @param SubjectType $subject_type Type of subject.
+	 * @return Subject[]
+	 */
+	public static function loop( SubjectType $subject_type ): array {
+		$args  = array(
+			'post_type'      => static::$post_type,
+			'post_status'    => 'publish',
+			'posts_per_page' => -1,
+			// @phpcs:ignore
+			'meta_query'     => array(
+				'key'     => 'subject_type',
+				'value'   => $subject_type->value,
+				'compare' => '=',
+			),
+		);
+		$posts = get_posts( $args );
+
+		return array_map(
+			fn( WP_Post $post ) => Subject::from_post( $post->ID ),
+			$posts
+		);
+	}
+}

From 8254fa4170f3ef6e59e410b674ecc9d8584733e6 Mon Sep 17 00:00:00 2001
From: ashfame <mail@ashfame.com>
Date: Fri, 27 Dec 2024 12:47:17 +0400
Subject: [PATCH 3/8] rename Transformers_Registry to Handlers_Registry

---
 src/plugin/class-engine.php                                   | 2 +-
 ...-transformers-registry.php => class-handlers-registry.php} | 2 +-
 src/plugin/class-subjects-controller.php                      | 4 ++--
 3 files changed, 4 insertions(+), 4 deletions(-)
 rename src/plugin/{class-transformers-registry.php => class-handlers-registry.php} (99%)

diff --git a/src/plugin/class-engine.php b/src/plugin/class-engine.php
index be88660c..898da322 100644
--- a/src/plugin/class-engine.php
+++ b/src/plugin/class-engine.php
@@ -9,7 +9,7 @@ class Engine {
 	public function __construct() {
 		require 'enum-subject-type.php';
 
-		require 'class-transformers-registry.php';
+		require 'class-handlers-registry.php';
 		require 'class-post-type-ui.php';
 		require 'class-transformer.php';
 		require 'class-subjects-controller.php';
diff --git a/src/plugin/class-transformers-registry.php b/src/plugin/class-handlers-registry.php
similarity index 99%
rename from src/plugin/class-transformers-registry.php
rename to src/plugin/class-handlers-registry.php
index 49fe442d..93742259 100644
--- a/src/plugin/class-transformers-registry.php
+++ b/src/plugin/class-handlers-registry.php
@@ -5,7 +5,7 @@
 use Exception;
 use InvalidArgumentException;
 
-class Transformers_Registry {
+class Handlers_Registry {
 	private static string $user_choice_meta_key_prefix = '_data_liberation_chosen_handler_';
 	private static array $handlers                     = array();
 
diff --git a/src/plugin/class-subjects-controller.php b/src/plugin/class-subjects-controller.php
index a80084f9..7b3f85cf 100644
--- a/src/plugin/class-subjects-controller.php
+++ b/src/plugin/class-subjects-controller.php
@@ -292,7 +292,7 @@ public function create_item( $request ): WP_REST_Response|WP_Error {
 		update_post_meta( $item['ID'], 'subject_type', $subject_type->value );
 
 		try {
-			Transformers_Registry::handle( $subject_type, Subject::from_post( $item['ID'] ) );
+			Handlers_Registry::handle( $subject_type, Subject::from_post( $item['ID'] ) );
 		} catch ( Exception $e ) {
 			return new WP_Error( $e->getCode(), $e->getMessage() );
 		}
@@ -322,7 +322,7 @@ public function update_item( $request ): WP_REST_Response|WP_Error {
 		$subject_type = $this->get_subject_type( $request );
 
 		try {
-			Transformers_Registry::handle( $subject_type, Subject::from_post( $item['ID'] ) );
+			Handlers_Registry::handle( $subject_type, Subject::from_post( $item['ID'] ) );
 		} catch ( Exception $e ) {
 			return new WP_Error( $e->getCode(), $e->getMessage() );
 		}

From dfc2928e80744e9b20ac8e90c10640ca0ab55320 Mon Sep 17 00:00:00 2001
From: ashfame <mail@ashfame.com>
Date: Fri, 27 Dec 2024 12:47:30 +0400
Subject: [PATCH 4/8] add Observers_Registry class

---
 src/plugin/class-observers-registry.php | 77 +++++++++++++++++++++++++
 1 file changed, 77 insertions(+)
 create mode 100644 src/plugin/class-observers-registry.php

diff --git a/src/plugin/class-observers-registry.php b/src/plugin/class-observers-registry.php
new file mode 100644
index 00000000..bacbb310
--- /dev/null
+++ b/src/plugin/class-observers-registry.php
@@ -0,0 +1,77 @@
+<?php
+
+namespace DotOrg\TryWordPress;
+
+use Exception;
+use InvalidArgumentException;
+
+class Observers_Registry {
+	private static array $observers = array();
+
+	/**
+	 * Add a observer for a specific subject type
+	 *
+	 * @param SubjectType $type The subject type for which observer should be registered.
+	 * @param array       $identifier Array containing unique slug and description.
+	 * @param callable    $observer The observer function.
+	 * @return void
+	 * @throws InvalidArgumentException If observer is not callable.
+	 */
+	public static function add( SubjectType $type, array $identifier, callable $observer ): void {
+		if ( ! is_callable( $observer ) ) {
+			throw new InvalidArgumentException( 'observer must be callable' );
+		}
+
+		if ( ! isset( $identifier['slug'] ) ) {
+			throw new InvalidArgumentException( 'Identifier slug must be defined' );
+		}
+
+		if ( ! isset( self::$observers[ $type->value ] ) ) {
+			self::$observers[ $type->value ] = array();
+		}
+
+		self::$observers[ $type->value ][ $identifier['slug'] ] = array(
+			'slug'        => $identifier['slug'],
+			'description' => $identifier['description'],
+			'observer'    => $observer,
+		);
+	}
+
+	/**
+	 * Check if observers exist for a type
+	 *
+	 * @param SubjectType $type The subject type to check for.
+	 * @return bool True if observers exist
+	 */
+	public static function has( SubjectType $type ): bool {
+		return isset( self::$observers[ $type->value ] ) && ! empty( self::$observers[ $type->value ] );
+	}
+
+	/**
+	 * Execute all observers for a type
+	 *
+	 * @param SubjectType $type The subject type to handle.
+	 * @param Subject     $subject Data to pass to observers.
+	 * @return void
+	 */
+	public static function observe( SubjectType $type, Subject $subject ): void {
+		if ( ! self::has( $type ) ) {
+			return;
+		}
+		foreach ( self::$observers[ $type->value ] as $registered_observer ) {
+			$registered_observer['observer']( $subject );
+		}
+	}
+
+	/**
+	 * Remove all observers for a type
+	 *
+	 * @param SubjectType $type The type to clear observers for.
+	 * @return void
+	 */
+	public static function clear( SubjectType $type ): void {
+		if ( isset( self::$observers[ $type->value ] ) ) {
+			unset( self::$observers[ $type->value ] );
+		}
+	}
+}

From c74f353d7752a48a76c93533b4ad0b4562285a34 Mon Sep 17 00:00:00 2001
From: ashfame <mail@ashfame.com>
Date: Fri, 27 Dec 2024 12:47:58 +0400
Subject: [PATCH 5/8] remove clear method from both Handlers and Observers
 registry

---
 src/plugin/class-handlers-registry.php  | 12 ------------
 src/plugin/class-observers-registry.php | 12 ------------
 2 files changed, 24 deletions(-)

diff --git a/src/plugin/class-handlers-registry.php b/src/plugin/class-handlers-registry.php
index 93742259..6c51c8bc 100644
--- a/src/plugin/class-handlers-registry.php
+++ b/src/plugin/class-handlers-registry.php
@@ -90,18 +90,6 @@ public static function handle( SubjectType $type, Subject $subject ): void {
 		}
 	}
 
-	/**
-	 * Remove all handlers for a type
-	 *
-	 * @param SubjectType $type The type to clear handlers for.
-	 * @return void
-	 */
-	public static function clear( SubjectType $type ): void {
-		if ( isset( self::$handlers[ $type->value ] ) ) {
-			unset( self::$handlers[ $type->value ] );
-		}
-	}
-
 	/**
 	 * Set user choice for what transformer to run for a subject type when multiples are registered
 	 *
diff --git a/src/plugin/class-observers-registry.php b/src/plugin/class-observers-registry.php
index bacbb310..38cdddc4 100644
--- a/src/plugin/class-observers-registry.php
+++ b/src/plugin/class-observers-registry.php
@@ -62,16 +62,4 @@ public static function observe( SubjectType $type, Subject $subject ): void {
 			$registered_observer['observer']( $subject );
 		}
 	}
-
-	/**
-	 * Remove all observers for a type
-	 *
-	 * @param SubjectType $type The type to clear observers for.
-	 * @return void
-	 */
-	public static function clear( SubjectType $type ): void {
-		if ( isset( self::$observers[ $type->value ] ) ) {
-			unset( self::$observers[ $type->value ] );
-		}
-	}
 }

From c06eeee33afcbe8a7c8c772a33043a8385fc0239 Mon Sep 17 00:00:00 2001
From: ashfame <mail@ashfame.com>
Date: Fri, 27 Dec 2024 12:52:47 +0400
Subject: [PATCH 6/8] announce subject to Observers registry before Handlers
 registry

---
 src/plugin/class-subjects-controller.php | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/plugin/class-subjects-controller.php b/src/plugin/class-subjects-controller.php
index 7b3f85cf..4f144b6c 100644
--- a/src/plugin/class-subjects-controller.php
+++ b/src/plugin/class-subjects-controller.php
@@ -292,7 +292,7 @@ public function create_item( $request ): WP_REST_Response|WP_Error {
 		update_post_meta( $item['ID'], 'subject_type', $subject_type->value );
 
 		try {
-			Handlers_Registry::handle( $subject_type, Subject::from_post( $item['ID'] ) );
+			$this->announce_subject( $subject_type, Subject::from_post( $item['ID'] ) );
 		} catch ( Exception $e ) {
 			return new WP_Error( $e->getCode(), $e->getMessage() );
 		}
@@ -322,7 +322,7 @@ public function update_item( $request ): WP_REST_Response|WP_Error {
 		$subject_type = $this->get_subject_type( $request );
 
 		try {
-			Handlers_Registry::handle( $subject_type, Subject::from_post( $item['ID'] ) );
+			$this->announce_subject( $subject_type, Subject::from_post( $item['ID'] ) );
 		} catch ( Exception $e ) {
 			return new WP_Error( $e->getCode(), $e->getMessage() );
 		}
@@ -465,4 +465,16 @@ private function get_subject_type( $request ): SubjectType {
 		preg_match( '/\/subjects\/([^\/]+)/', $request->get_route(), $matches );
 		return SubjectType::tryFrom( $matches[1] );
 	}
+
+	/**
+	 * Announce subject to Observers_Registry & Handlers_Registry
+	 *
+	 * @param SubjectType $subject_type Type of subject to announce.
+	 * @param Subject     $subject Subject instance to announce.
+	 * @throws Exception Handlers_Registry::handle can throw an exception.
+	 */
+	private function announce_subject( SubjectType $subject_type, Subject $subject ): void {
+		Observers_Registry::observe( $subject_type, $subject );
+		Handlers_Registry::handle( $subject_type, $subject );
+	}
 }

From 04a090225fe1e11f50050f57def10421c33211c7 Mon Sep 17 00:00:00 2001
From: ashfame <mail@ashfame.com>
Date: Fri, 27 Dec 2024 13:18:09 +0400
Subject: [PATCH 7/8] have our transformers also use Ops class

---
 src/plugin/class-transformer.php | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/plugin/class-transformer.php b/src/plugin/class-transformer.php
index 22a8ac80..81f9ae82 100644
--- a/src/plugin/class-transformer.php
+++ b/src/plugin/class-transformer.php
@@ -7,7 +7,7 @@ class Transformer {
 	public const string META_KEY_LIBERATED_OUTPUT = '_data_liberation_output';
 
 	public function __construct() {
-		TransformersRegistry::add(
+		Ops::handle(
 			SubjectType::BLOGPOST,
 			array(
 				'slug'        => 'try_wordpress',
@@ -19,7 +19,7 @@ public function __construct() {
 			)
 		);
 
-		TransformersRegistry::add(
+		Ops::handle(
 			SubjectType::PAGE,
 			array(
 				'slug'        => 'try_wordpress',

From af1ebce4730401d3c8c3aaed12671584ff272346 Mon Sep 17 00:00:00 2001
From: ashfame <mail@ashfame.com>
Date: Fri, 27 Dec 2024 13:27:27 +0400
Subject: [PATCH 8/8] load observers registry + reorder require calls

---
 src/plugin/class-engine.php | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/src/plugin/class-engine.php b/src/plugin/class-engine.php
index 898da322..a88e6840 100644
--- a/src/plugin/class-engine.php
+++ b/src/plugin/class-engine.php
@@ -8,17 +8,22 @@ class Engine {
 
 	public function __construct() {
 		require 'enum-subject-type.php';
+		require 'class-subject.php';
+		require 'class-schema.php';
 
 		require 'class-handlers-registry.php';
-		require 'class-post-type-ui.php';
-		require 'class-transformer.php';
+		require 'class-observers-registry.php';
+
 		require 'class-subjects-controller.php';
+
 		require 'class-storage.php';
-		require 'class-schema.php';
-		require 'utils.php';
-		require 'class-subject.php';
+
+		require 'class-post-type-ui.php';
+		require 'class-transformer.php';
 		require 'class-ops.php';
 
+		require 'utils.php';
+
 		( function () {
 			new Transformer();
 			new Post_Type_UI( self::STORAGE_POST_TYPE );