solidtime/app/Http/Requests/V1/Member/MemberMergeIntoRequest.php

<?php

declare(strict_types=1);

namespace App\Http\Requests\V1\Member;

use App\Http\Requests\V1\BaseFormRequest;
use App\Models\Member;
use App\Models\Organization;
use Illuminate\Contracts\Validation\ValidationRule;
use Illuminate\Database\Eloquent\Builder;
use Korridor\LaravelModelValidationRules\Rules\ExistsEloquent;

/**
 * @property Organization $organization
 */
class MemberMergeIntoRequest extends BaseFormRequest
{
    /**
     * Get the validation rules that apply to the request.
     *
     * @return array<string, array<string|ValidationRule|\Illuminate\Contracts\Validation\Rule>>
     */
    public function rules(): array
    {
        return [
            // ID of the member to which the data should be transferred (destination)
            'member_id' => [
                'string',
                ExistsEloquent::make(Member::class, null, function (Builder $builder): Builder {
                    /** @var Builder<Member> $builder */
                    return $builder->whereBelongsTo($this->organization, 'organization');
                })->uuid(),
            ],
        ];
    }

    public function getMemberId(): string
    {
        return (string) $this->input('member_id');
    }
}