use-case-example.php

<?php

class CreateUserUseCase {
    public function __construct(Repository $repository) {
    
    }
    
    public function execute(string $username, string $password) {
    
    }
}

//
// READ
//

class Pagination {
    private $limit;
    private $offset;
    
    public function __construct(int $limit, int $offset)
    {
        $this->limitGuard($limit);
        $this->offsetGuard($offset, $limit);
        
        $this->limit = $limit;
        $this->offset = $offset;
    }
    
    public function limit()
    {
        return $this->limit;
    }
    
    public function offset()
    {
        return $this->offset;
    }

    private function limitGuard(int $limit)
    {
        if (!in_array($limit, [10, 20, 30, 40, 50])) {
            throw new InvalidLimitException();
        }
    }
    
    private function offsetGuard(int $offset, int $limit)
    {
        if ($offset % $limit !== 0) {
            throw new InvalidOffsetException();
        }
    }
}

class ResultsList implements JsonSerializable
{
    public $results;
    public $limit;
    public $total;
    public $pagination = [
        'currentPage' => 5,
        'lastPage' => 66
    ];
    
    public function __construct(array $results, int $limit, int $total, int $offset)
    {
        $this->results = $results;
        $this->limit = $limit;
        $this->total = $total;
        $this->pagination['currentPage'] = ceil($total / $offset);
        $this->pagination['lastPage'] = ceil($total / $limit);
    }
    
    public function jsonSerialize()
    {
        return [
            'results' => $this->results,
            'limit' => $this->limit,
            'total' => $this->total,
            'pagination' => $this->pagination
        ];
    }
}

class UserCriteria
{
    private $category;
    
    public function __construct(int $categoryId)
    {
        $this->category = $categoryId;
    }
    
    public function getCategory()
    {
        return $this->category;
    }
}

class UserListingUseCase
{
    public function __construct(DBAL $dbal)
    {
    
    }
    
    public function execute(UserCriteria $criteria, Pagination $pagination) : ResultsList
    {
        $query = $dbal->newQueryBuilder();
        
        if ($criteria->getCategory()) {
            $query->filter('category', $criteria->getCategory());
        }
        
        // set limit
        // set offset
        
        $results = array_map(function($item) {
            return new UserListDto($item);
        }, $query->execute());
        
        return new ResultsList($results, $total, $pagination->limit(), $pagination->offset());
    }
}