HasOneCustomResolver.php

<?php

namespace App\Xxx;

use Illuminate\Database\Eloquent\Builder;
use Illuminate\Database\Eloquent\Collection;
use Illuminate\Database\Eloquent\Relations\HasOne;

/**
 * Class HasOneCustomResolver
 * Eloquent Modelのリレーションとして、テーブルではなく任意のオブジェクトを差し込むためのクラス
 *
 * Eloquent Model側には以下の様にリレーションを定義する。
 * public function childItem() {
 * 
 *     $relation = new HasOneCustomResolver($this->newQuery(), ChildItem::class);
 *     
 *     $resolver = function(Model $parent) {
 *         // よしなに$childItemを生成して返す
 *         return new ChildItem();
 *     };
 *     
 *     $relation->setRelationResolver($resolver);
 *     
 *     return $relation;
 * }
 *
 * @package App\Xxx
 */
class HasOneCustomResolver extends HasOne
{
    protected $query;

    /**
     * @var \Closure
     */
    private $relationResolver;

    public function __construct(Builder $query, string $relatedClass)
    {
        $parent = new $relatedClass;
        parent::__construct($query, $parent, '', '');
    }

    public function setRelationResolver(\Closure $relationResolver)
    {
        $this->relationResolver = $relationResolver;
    }

    /**
     * Set the constraints for an eager load of the relation.
     *
     * @param  array $models
     * @return void
     */
    public function addEagerConstraints(array $models)
    {
        // TODO: Implement addEagerConstraints() method.
    }

    /**
     * Initialize the relation on a set of models.
     *
     * @param  array $models
     * @param  string $relation
     * @return array
     */
    public function initRelation(array $models, $relation)
    {
        return $models;
    }

    /**
     * Match the eagerly loaded results to their parents.
     *
     * @param  array $models
     * @param  \Illuminate\Database\Eloquent\Collection $results
     * @param  string $relation
     * @return array
     */
    public function match(array $models, Collection $results, $relation)
    {
        foreach ($models as $model) {
            $model->setRelation($relation, $this->relationResolver->call($this, $model));
        }

        $children = [];
        foreach ($models as &$model) {
            $children[] = &$model->$relation;
        }

        if (count($models) > 0) {
            $query = $this->getQuery();
            $query->setModel($this->parent);
            $builder = $query->applyScopes();
            $builder->eagerLoadRelations($children);
        }

        return $models;
    }

    /**
     * Get the results of the relationship.
     *
     * @return mixed
     */
    public function getResults()
    {
        // TODO: Implement match() method.
    }

    public function getEager()
    {
        return new Collection([]);
    }
}