namespace App\Entity;

use ApiPlatform\Metadata\GetCollection;
use App\State\BookCollectionProvider;
use Doctrine\ORM\Mapping as ORM;

#[ORM\Entity]
#[GetCollection(
    output: BookOutput::class,
    provider: BookCollectionProvider::class,
)]
class Book
{
    #[ORM\Id]
    #[ORM\GeneratedValue]
    #[ORM\Column]
    public ?int $id = null;

    #[ORM\Column(length: 255)]
    public ?string $name = null;
}

namespace App\Entity;

final class BookOutput
{
    public ?int $id = null;
    public ?string $name = null;
    public string $isbn = 'some-hardcoded-isbn';
}

namespace App\State;

use ApiPlatform\Doctrine\Orm\State\CollectionProvider;
use ApiPlatform\Metadata\Operation;
use ApiPlatform\State\ProviderInterface;
use App\Entity\BookOutput;
use Generator;

final readonly class BookCollectionProvider implements ProviderInterface
{
    public function __construct(
        private CollectionProvider $collectionProvider,
    ) {
    }

    public function provide(Operation $operation, array $uriVariables = [], array $context = []): Generator
    {
        $results = $this->collectionProvider->provide($operation, $uriVariables, $context);

        foreach ($results as $book) {
            $output = new BookOutput();
            $output->id = $book->id;
            $output->name = $book->name;

            yield $output;
        }
    }
}