Attainly/backend/app/Element/EloquentElementRepository.php

<?php

namespace App\Element;

use App\Set\Set;
use App\Set\SetRepository;
use DomainException;
use RuntimeException;

class EloquentElementRepository implements ElementRepository
{
    public function __construct(
        private SetRepository $setRepository,
    ) {}

    public function create(CreateElementDto $dto): Element
    {
        $this->validateParentSet($dto);
        $position = $this->nextPosition(
            $dto->set,
            $dto->parentElement,
        );
        $model = ElementModel::create([
            'set_id' => $dto->set->getId(),
            'name' => $dto->name,
            'kind' => $dto->kind,
            'parent_element_id' => $dto->parentElement?->getId(),
            'position' => $position,
        ]);

        return new Element(
            id: $model->id,
            name: $model->name,
            kind: $model->kind,
            set: $dto->set,
            parentElement: $dto->parentElement,
            position: $model->position,
        );
    }

    public function find(int $id): ?Element
    {
        $model = ElementModel::find($id);

        return $model === null ? null : $this->toDomain($model);
    }

    public function findTopLevelBySet(Set $set): array
    {
        $models = ElementModel::query()
            ->where('set_id', $set->getId())
            ->whereNull('parent_element_id')
            ->orderBy('position')
            ->orderBy('id')
            ->get();
        $elements = [];

        foreach ($models as $model) {
            $elements[] = $this->toDomainWithRelations(
                model: $model,
                set: $set,
                parentElement: null,
            );
        }

        return $elements;
    }

    public function findByParentElement(Element $parentElement): array
    {
        $models = ElementModel::query()
            ->where('set_id', $parentElement->getSet()->getId())
            ->where('parent_element_id', $parentElement->getId())
            ->orderBy('position')
            ->orderBy('id')
            ->get();
        $elements = [];

        foreach ($models as $model) {
            $elements[] = $this->toDomainWithRelations(
                model: $model,
                set: $parentElement->getSet(),
                parentElement: $parentElement,
            );
        }

        return $elements;
    }

    /**
     * @throws DomainException
     */
    private function validateParentSet(CreateElementDto $dto): void
    {
        $parentElement = $dto->parentElement;
        if ($parentElement === null) {
            return;
        }

        if ($parentElement->getSet()->getId() !== $dto->set->getId()) {
            throw new DomainException(
                'parent element must belong to the same set',
            );
        }
    }

    private function nextPosition(
        Set $set,
        ?Element $parentElement,
    ): int {
        $query = ElementModel::query()
            ->where('set_id', $set->getId());
        if ($parentElement === null) {
            $query->whereNull('parent_element_id');
        } else {
            $query->where('parent_element_id', $parentElement->getId());
        }

        $currentMaximum = $query->max('position');
        if ($currentMaximum === null) {
            return 1;
        }

        return (int) $currentMaximum + 1;
    }

    private function toDomain(ElementModel $model): Element
    {
        $set = $this->findSet($model->set_id);

        $parentElement = null;
        if ($model->parent_element_id !== null) {
            $parentElement = $this->find($model->parent_element_id);
            if ($parentElement === null) {
                throw new RuntimeException('element parent not found');
            }
        }

        return $this->toDomainWithRelations(
            model: $model,
            set: $set,
            parentElement: $parentElement,
        );
    }

    private function toDomainWithRelations(
        ElementModel $model,
        Set $set,
        ?Element $parentElement,
    ): Element {
        return new Element(
            id: $model->id,
            name: $model->name,
            kind: $model->kind,
            set: $set,
            parentElement: $parentElement,
            position: $model->position,
        );
    }

    private function findSet(int $id): Set
    {
        foreach ($this->setRepository->all() as $set) {
            if ($set->getId() === $id) {
                return $set;
            }
        }

        throw new RuntimeException('element set not found');
    }
}