<?php
declare(strict_types=1);
namespace Flownative\Example\GraphQL;

final class QueryResolver
{
    /**
     * @param $_
     * @param array $arguments
     * @return array
     */
    public function ping($_, array $arguments): array
    {
        return [
            'pong' => time()
        ];
    }
}

<?php
declare(strict_types=1);
namespace Flownative\Example\GraphQL;

use Flownative\GraphQL\EndpointInterface;
use GraphQL\Executor\ExecutionResult;
use GraphQL\GraphQL;
use GraphQL\Type\Schema;

final class Endpoint implements EndpointInterface
{
    /**
     * @var QueryResolver
     */
    protected $queryResolver;

    /**
     * @param QueryResolver $queryResolver
     */
    public function __construct(QueryResolver $queryResolver)
    {
        $this->queryResolver = $queryResolver;
    }

    /**
     * @return string
     */
    public static function getPath(): string
    {
        return '/api/graphql';
    }

    /**
     * @return string
     */
    public function getSchemaUri(): string
    {
        return 'resource://Flownative.Example/Private/GraphQL/schema.graphql';
    }

    /**
     * @param Schema $schema
     * @param array $input
     * @return ExecutionResult
     */
    public function executeQuery(Schema $schema, array $input): ExecutionResult
    {
        return GraphQL::executeQuery(
            $schema,
            $input['query'],
            $this->getRootValue(),
            null,
            $input['variables'] ?? null,
        );
    }

    /**
     * @return mixed
     */
    private function getRootValue(): array
    {
        $queryResolver = $this->queryResolver;
        return [
            'ping' => static function ($rootValue, array $args, $context) use ($queryResolver) {
                return $queryResolver->ping($rootValue, $args);
            }
        ];
    }

    /**
     * @return callable|null
     */
    public function getTypeConfigDecorator(): ?callable
    {
        return null;
    }
}