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

use Magento\Framework\App\Filesystem\DirectoryList;
use Magento\Framework\Config\File\ConfigFilePool;
use Magento\Framework\Exception\FileSystemException;
use Magento\Framework\Filesystem\DriverPool;

/**
* Allows to read configurations from different config files.
*
* @see Reader The reader for merged configurations
*/
class FileReader
{
/**
* The list of directories.
*
* @var DirectoryList
*/
private $dirList;

/**
* The pool of config files.
*
* @var ConfigFilePool
*/
private $configFilePool;

/**
* The pool of stream drivers.
*
* @var DriverPool
*/
private $driverPool;

/**
* @param DirectoryList $dirList The list of directories
* @param DriverPool $driverPool The pool of config files
* @param ConfigFilePool $configFilePool The pool of stream drivers
*/
public function __construct(
DirectoryList $dirList,
DriverPool $driverPool,
ConfigFilePool $configFilePool
) {
$this->dirList = $dirList;
$this->configFilePool = $configFilePool;
$this->driverPool = $driverPool;
}

/**
* Loads the configuration file.
*
* @param string $fileKey The file key
* @return array The configurations array
* @throws FileSystemException If file can not be read
* @throws \Exception If file key is not correct
*/
public function load($fileKey)
{
$path = $this->dirList->getPath(DirectoryList::CONFIG);
$fileDriver = $this->driverPool->getDriver(DriverPool::FILE);
$filePath = $path . '/' . $this->configFilePool->getPath($fileKey);

if ($fileDriver->isExists($filePath)) {
return include $filePath;
}

return [];
}
}