introduce TransformersRegistry class to use in registration of transf…

…ormers

src/plugin/class-transformersregistry.php

@@ -0,0 +1,78 @@
+<?php
+
+namespace DotOrg\TryWordPress;
+
+use InvalidArgumentException;
+
+class TransformersRegistry {
+	private static array $handlers = array();
+
+	/**
+	 * Add a handler for a specific subject type
+	 *
+	 * @param string   $type The subject type to handle.
+	 * @param array    $identifier Array containing unique slug and description.
+	 * @param callable $handler The handler function.
+	 * @return void
+	 * @throws InvalidArgumentException If handler is not callable.
+	 */
+	public static function add( string $type, array $identifier, callable $handler ): void {
+		if ( ! is_callable( $handler ) ) {
+			throw new InvalidArgumentException( 'Handler must be callable' );
+		}
+
+		if ( ! isset( $identifier['slug'] ) ) {
+			throw new InvalidArgumentException( 'Identifier slug must be defined' );
+		}
+
+		if ( ! isset( self::$handlers[ $type ] ) ) {
+			self::$handlers[ $type ] = array();
+		}
+
+		self::$handlers[ $type ][] = $handler;
+	}
+
+	/**
+	 * Check if handlers exist for a type
+	 *
+	 * @param string $type The type to check.
+	 * @return bool True if handlers exist
+	 */
+	public static function has( string $type ): bool {
+		return isset( self::$handlers[ $type ] ) && ! empty( self::$handlers[ $type ] );
+	}
+
+	/**
+	 * Execute all handlers for a type
+	 *
+	 * @TODO: Invoke this function at the right place in code
+	 *
+	 * @param string     $type The type to handle.
+	 * @param mixed|null $data Data to pass to handlers.
+	 * @return array Results from all handlers
+	 */
+	public static function handle( string $type, mixed $data = null ): array {
+		if ( ! self::has( $type ) ) {
+			return array();
+		}
+
+		$results = array();
+		foreach ( self::$handlers[ $type ] as $handler ) {
+			$results[] = $handler( $data );
+		}
+
+		return $results;
+	}
+
+	/**
+	 * Remove all handlers for a type
+	 *
+	 * @param string $type The type to clear handlers for.
+	 * @return void
+	 */
+	public static function clear( string $type ): void {
+		if ( isset( self::$handlers[ $type ] ) ) {
+			unset( self::$handlers[ $type ] );
+		}
+	}
+}