<?php

namespace Box\Spout\Common\Helper;

use Box\Spout\Common\Exception\IOException;

/**
 * Class FileSystemHelper
 * This class provides helper functions to help with the file system operations
 * like files/folders creation & deletion
 *
 * @package Box\Spout\Common\Helper
 */
class FileSystemHelper {

	/** @var string Real path of the base folder where all the I/O can occur */
	protected $baseFolderRealPath;

	/**
	 * @param string $baseFolderPath The path of the base folder where all the I/O can occur
	 */
	public function __construct( $baseFolderPath ) {
		$this->baseFolderRealPath = realpath( $baseFolderPath );
	}

	/**
	 * Creates an empty folder with the given name under the given parent folder.
	 *
	 * @param string $parentFolderPath The parent folder path under which the folder is going to be created
	 * @param string $folderName The name of the folder to create
	 * @return string Path of the created folder
	 * @throws \Box\Spout\Common\Exception\IOException If unable to create the folder or if the folder path is not inside of the base folder
	 */
	public function createFolder( $parentFolderPath, $folderName ) {
		$this->throwIfOperationNotInBaseFolder( $parentFolderPath );

		$folderPath = $parentFolderPath . '/' . $folderName;

		$wasCreationSuccessful = mkdir( $folderPath, 0777, true );
		if ( ! $wasCreationSuccessful ) {
			throw new IOException( "Unable to create folder: $folderPath" );
		}

		return $folderPath;
	}

	/**
	 * Creates a file with the given name and content in the given folder.
	 * The parent folder must exist.
	 *
	 * @param string $parentFolderPath The parent folder path where the file is going to be created
	 * @param string $fileName The name of the file to create
	 * @param string $fileContents The contents of the file to create
	 * @return string Path of the created file
	 * @throws \Box\Spout\Common\Exception\IOException If unable to create the file or if the file path is not inside of the base folder
	 */
	public function createFileWithContents( $parentFolderPath, $fileName, $fileContents ) {
		 $this->throwIfOperationNotInBaseFolder( $parentFolderPath );

		$filePath = $parentFolderPath . '/' . $fileName;

		$wasCreationSuccessful = file_put_contents( $filePath, $fileContents );
		if ( $wasCreationSuccessful === false ) {
			throw new IOException( "Unable to create file: $filePath" );
		}

		return $filePath;
	}

	/**
	 * Delete the file at the given path
	 *
	 * @param string $filePath Path of the file to delete
	 * @return void
	 * @throws \Box\Spout\Common\Exception\IOException If the file path is not inside of the base folder
	 */
	public function deleteFile( $filePath ) {
		$this->throwIfOperationNotInBaseFolder( $filePath );

		if ( file_exists( $filePath ) && is_file( $filePath ) ) {
			unlink( $filePath );
		}
	}

	/**
	 * Delete the folder at the given path as well as all its contents
	 *
	 * @param string $folderPath Path of the folder to delete
	 * @return void
	 * @throws \Box\Spout\Common\Exception\IOException If the folder path is not inside of the base folder
	 */
	public function deleteFolderRecursively( $folderPath ) {
		$this->throwIfOperationNotInBaseFolder( $folderPath );

		$itemIterator = new \RecursiveIteratorIterator(
			new \RecursiveDirectoryIterator( $folderPath, \RecursiveDirectoryIterator::SKIP_DOTS ),
			\RecursiveIteratorIterator::CHILD_FIRST
		);

		foreach ( $itemIterator as $item ) {
			if ( $item->isDir() ) {
				rmdir( $item->getPathname() );
			} else {
				unlink( $item->getPathname() );
			}
		}

		rmdir( $folderPath );
	}

	/**
	 * All I/O operations must occur inside the base folder, for security reasons.
	 * This function will throw an exception if the folder where the I/O operation
	 * should occur is not inside the base folder.
	 *
	 * @param string $operationFolderPath The path of the folder where the I/O operation should occur
	 * @return void
	 * @throws \Box\Spout\Common\Exception\IOException If the folder where the I/O operation should occur is not inside the base folder
	 */
	protected function throwIfOperationNotInBaseFolder( $operationFolderPath ) {
		$operationFolderRealPath = realpath( $operationFolderPath );
		$isInBaseFolder          = ( strpos( $operationFolderRealPath, $this->baseFolderRealPath ) === 0 );
		if ( ! $isInBaseFolder ) {
			throw new IOException( "Cannot perform I/O operation outside of the base folder: {$this->baseFolderRealPath}" );
		}
	}
}