<?php namespace GermanAirlinesVa\Graphql\Classes;

use Closure;
use Nuwave\Lighthouse\Schema\Values\FieldValue;
use GraphQL\Type\Definition\ResolveInfo;
use Cms\Classes\CodeParser;
use Nuwave\Lighthouse\Schema\ResolverProvider as LighthouseResolverProvider;

class ResolverProvider extends LighthouseResolverProvider
{
  /**
   * Provide a field resolver in case no resolver directive is defined for a field.
   *
   * @param  \Nuwave\Lighthouse\Schema\Values\FieldValue  $fieldValue
   * @return \Closure
   */
  public function provideResolver(FieldValue $fieldValue): Closure
  {
    return function ($root, array $args, $context, ResolveInfo $resolveInfo) use ($fieldValue) {
      $fieldName = $fieldValue->getFieldName();
      // use local graph resolver in code section if existent
      if ($graphObj = $context->source->findGraph($fieldName)) {
        /* @var $graphObj \GermanAirlinesVa\Graphql\Classes\Graph */
        $parser = new CodeParser($graphObj);
        $codeObj = $parser->source($graphObj, null, new GraphController($graphObj, $args));
        $resolveMethod = 'resolve' . studly_case($fieldName);

        if (method_exists($codeObj, $resolveMethod)) {
          return $codeObj->$resolveMethod($root, $args, $context, $resolveInfo);
        }
      }

      // default resolver
      return parent::provideResolver($fieldValue)($root, $args, $context, $resolveInfo);
    };
  }
}