wpmind/modules/api-gateway/includes/Pipeline/RouteMiddleware.php

<?php
/**
 * Route Middleware
 *
 * Pipeline stage that dispatches requests to WPMind's PublicAPI.
 *
 * @package WPMind\Modules\ApiGateway\Pipeline
 * @since 1.0.0
 */

declare(strict_types=1);

namespace WPMind\Modules\ApiGateway\Pipeline;

use WPMind\Modules\ApiGateway\Transform\ModelMapper;
use WPMind\Modules\ApiGateway\Transform\ResponseTransformer;
use WPMind\Modules\ApiGateway\Stream\SseStreamController;
use WPMind\Modules\ApiGateway\SchemaManager;

/**
 * Class RouteMiddleware
 *
 * Reads the internal payload from the context and calls the
 * appropriate PublicAPI method based on the operation type.
 */
final class RouteMiddleware implements GatewayStageInterface {

	/**
	 * Process the gateway request context.
	 *
	 * @param GatewayRequestContext $context Shared request context.
	 */
	public function process( GatewayRequestContext $context ): void {
		if ( $context->has_error() ) {
			return;
		}

		$payload   = $context->get_internal_payload();
		$operation = $payload['operation'] ?? $context->operation();

		match ( $operation ) {
			'chat.completions' => $this->handle_chat( $context, $payload ),
			'embeddings'       => $this->handle_embeddings( $context, $payload ),
			'responses'        => $this->handle_chat( $context, $payload ),
			'models'           => $this->handle_models( $context ),
			'model_detail'     => $this->handle_model_detail( $context ),
			'status'           => $this->handle_status( $context ),
			default            => $context->set_error(
				new \WP_Error(
					'unsupported_operation',
					sprintf( 'Unsupported operation: %s', sanitize_text_field( $operation ) ),
					[ 'status' => 400 ]
				)
			),
		};
	}

	/**
	 * Handle a chat completions request.
	 *
	 * @param GatewayRequestContext $context Pipeline context.
	 * @param array                 $payload Internal payload.
	 */
	private function handle_chat( GatewayRequestContext $context, array $payload ): void {
		$messages = $payload['messages'] ?? [];
		$options  = $payload['options'] ?? [];
		$stream   = $payload['stream'] ?? false;

		// For 'auto' provider, omit provider from options to let WPMind route.
		if ( ( $options['provider'] ?? '' ) === 'auto' ) {
			unset( $options['provider'], $options['model'] );
		}

		if ( $stream ) {
			// Phase 6: SSE streaming via SseStreamController.
			// If slot acquisition fails, the controller sets an error
			// on the context and returns, allowing the pipeline to
			// produce a normal JSON error response.
			$controller = new SseStreamController();
			$controller->serve_chat_stream( $context );

			// If we reach here, slot acquisition failed and the error
			// is already set on the context. The pipeline continues.
			return;
		}

		$api = \WPMind\API\PublicAPI::instance();

		/** @var array|\WP_Error $result */
		$result = $api->chat( $messages, $options );

		if ( is_wp_error( $result ) ) {
			$context->set_error( $result );
			return;
		}

		$context->set_internal_result( $result );
	}

	/**
	 * Handle an embeddings request.
	 *
	 * @param GatewayRequestContext $context Pipeline context.
	 * @param array                 $payload Internal payload.
	 */
	private function handle_embeddings( GatewayRequestContext $context, array $payload ): void {
		$input   = $payload['input'] ?? '';
		$options = $payload['options'] ?? [];

		// For 'auto' provider, omit provider from options.
		if ( ( $options['provider'] ?? '' ) === 'auto' ) {
			unset( $options['provider'], $options['model'] );
		}

		$api = \WPMind\API\PublicAPI::instance();

		/** @var array|\WP_Error $result */
		$result = $api->embed( $input, $options );

		if ( is_wp_error( $result ) ) {
			$context->set_error( $result );
			return;
		}

		$context->set_internal_result( $result );
	}

	/**
	 * Handle a models list request.
	 *
	 * @param GatewayRequestContext $context Pipeline context.
	 */
	private function handle_models( GatewayRequestContext $context ): void {
		$models      = ModelMapper::get_available_models();
		$transformer = new ResponseTransformer();
		$data        = $transformer->transform_models( $models );

		$context->set_internal_result( $data );
	}

	/**
	 * Handle a single model detail request.
	 *
	 * @param GatewayRequestContext $context Pipeline context.
	 */
	private function handle_model_detail( GatewayRequestContext $context ): void {
		$model_id = $context->rest_request()->get_param( 'model_id' );

		if ( $model_id === null || $model_id === '' ) {
			$context->set_error( new \WP_Error(
				'model_not_found',
				'Model ID is required.',
				[ 'status' => 400 ]
			) );
			return;
		}

		$resolved = ModelMapper::resolve( (string) $model_id );

		if ( $resolved === null ) {
			$context->set_error( new \WP_Error(
				'model_not_found',
				sprintf( 'Model "%s" is not available.', sanitize_text_field( (string) $model_id ) ),
				[ 'status' => 404 ]
			) );
			return;
		}

		$context->set_internal_result( [
			'id'       => (string) $model_id,
			'object'   => 'model',
			'created'  => 0,
			'owned_by' => 'wpmind',
		] );
	}

	/**
	 * Handle a gateway status request.
	 *
	 * Returns basic gateway health and configuration info.
	 *
	 * @param GatewayRequestContext $context Pipeline context.
	 */
	private function handle_status( GatewayRequestContext $context ): void {
		$context->set_internal_result( [
			'status'         => 'ok',
			'version'        => '1.0.0',
			'endpoints'      => [
				'/mind/v1/chat/completions',
				'/mind/v1/embeddings',
				'/mind/v1/responses',
				'/mind/v1/models',
				'/mind/v1/models/{model_id}',
				'/mind/v1/status',
			],
			'schema_version' => SchemaManager::get_schema_version(),
		] );
	}
}