<?php
/**
* Copyright © Magento, Inc. All rights reserved.
* See COPYING.txt for license details.
*/
namespace Magento\Framework\App\Http;

use Magento\Framework\App\ObjectManager;
use Magento\Framework\Serialize\Serializer\Json;

/**
* Context data for requests
*/
class Context
{
/**
* Currency cache context
*/
const CONTEXT_CURRENCY = 'current_currency';

/**
* Data storage
*
* @var array
*/
protected $data = [];

/**
* @var array
*/
protected $default = [];

/**
* @var Json
*/
private $serializer;

/**
* @param array $data
* @param array $default
* @param Json|null $serializer
*/
public function __construct(array $data = [], array $default = [], Json $serializer = null)
{
$this->data = $data;
$this->default = $default;
$this->serializer = $serializer ?: ObjectManager::getInstance()->get(Json::class);
}

/**
* Data setter
*
* @param string $name
* @param mixed $value
* @param mixed $default
* @return \Magento\Framework\App\Http\Context
*/
public function setValue($name, $value, $default)
{
if ($default !== null) {
$this->default[$name] = $default;
}
$this->data[$name] = $value;
return $this;
}

/**
* Unset data from vary array
*
* @param string $name
* @return null
*/
public function unsValue($name)
{
unset($this->data[$name]);
return $this;
}

/**
* Data getter
*
* @param string $name
* @return mixed|null
*/
public function getValue($name)
{
return $this->data[$name] ?? ($this->default[$name] ?? null);
}

/**
* Return all data
*
* @return array
*/
public function getData()
{
$data = [];
foreach ($this->data as $name => $value) {
if ($value && $value != $this->default[$name]) {
$data[$name] = $value;
}
}
return $data;
}

/**
* Return vary string to be used as a part of page cache identifier
*
* @return string|null
*/
public function getVaryString()
{
$data = $this->getData();
if (!empty($data)) {
ksort($data);
return sha1($this->serializer->serialize($data));
}
return null;
}

/**
* Get data and default data in "key-value" format
*
* @return array
*/
public function toArray()
{
return [
'data' => $this->data,
'default' => $this->default
];
}
}