page.php

<?php
 
namespace Bitrix\Main\Engine\Response\DataType;
 
use Bitrix\Main\Type\Contract\Arrayable;
 
final class Page implements Arrayable, \IteratorAggregate, \ArrayAccess, \JsonSerializable
{
    private $id;
    private $items = [];
 
    private $totalCount;
    private $calculatedTotalCount;
 
    public function __construct($id, $items, $totalCount)
    {
        $data = [];
        if (!is_array($items) && $items instanceof \Traversable)
        {
            foreach ($items as $item)
            {
                $data[] = $item;
            }
        }
        else
        {
            $data = $items;
        }
 
        $this->id = $id;
        $this->items = $data;
        $this->totalCount = $totalCount;
    }
 
    public function getTotalCount()
    {
        if ($this->totalCount instanceof \Closure)
        {
            $this->calculatedTotalCount = call_user_func($this->totalCount);
        }
        else
        {
            $this->calculatedTotalCount = $this->totalCount;
        }
 
        return $this->calculatedTotalCount;
    }
 
 
    public function getId()
    {
        return $this->id;
    }
 
    public function getItems()
    {
        return $this->items;
    }
 
    public function getIterator()
    {
        return new \ArrayIterator($this->items);
    }
 
    public function offsetExists($offset)
    {
        return isset($this->items[$offset]) || array_key_exists($offset, $this->items);
    }
 
    #[\ReturnTypeWillChange]
    public function offsetGet($offset)
    {
        if (isset($this->items[$offset]) || array_key_exists($offset, $this->items))
        {
            return $this->items[$offset];
        }
 
        return null;
    }
 
    public function offsetSet($offset, $value): void
    {
        if($offset === null)
        {
            $this->items[] = $value;
        }
        else
        {
            $this->items[$offset] = $value;
        }
    }
 
    public function offsetUnset($offset): void
    {
        unset($this->items[$offset]);
    }
 
    public function jsonSerialize(): array
    {
        return $this->toArray();
    }
 
    public function toArray()
    {
        return [
            $this->id => $this->items
        ];
    }
}