//********************************** Banshee Engine (www.banshee3d.com) **************************************************//
//**************** Copyright (c) 2016 Marko Pintera (marko.pintera@gmail.com). All rights reserved. **********************//
#pragma once

#include "BsPrerequisitesUtil.h"

namespace BansheeEngine
{
	/** @addtogroup Filesystem
	 *  @{
	 */

	/** Utility class for dealing with files. */
	class BS_UTILITY_EXPORT FileSystem
	{
	public:
		/**
		 * Opens a file and returns a data stream capable of reading or writing to that file.
		 *
		 * @param[in]	fullPath	Full path to a file.
		 * @param[in]	readOnly	(optional) If true, returned stream will only be readable.
		 */
		static SPtr<DataStream> openFile(const Path& fullPath, bool readOnly = true);

		/**
		 * Opens a file and returns a data stream capable of reading and writing to that file. If file doesn't exist new
		 * one will be created.
		 *
		 * @param[in]	fullPath	Full path to a file.
		 */
		static SPtr<DataStream> createAndOpenFile(const Path& fullPath);

		/**
		 * Returns the size of a file in bytes.
		 *
		 * @param[in]	fullPath	Full path to a file.
		 */
		static UINT64 getFileSize(const Path& fullPath);

		/**
		 * Deletes a file or a folder at the specified path.
		 *
		 * @param[in]	fullPath   	Full path to a file or a folder..
		 * @param[in]	recursively	(optional) If true, folders will have their contents deleted as well. Otherwise an
		 *							exception will be thrown for non-empty folders.
		 */
		static void remove(const Path& fullPath, bool recursively = true);

		/**
		 * Moves a file or a folder from one to another path. This can also be used as a rename operation.
		 *
		 * @param[in]	oldPath			 	Full path to the old file/folder.
		 * @param[in]	newPath			 	Full path to the new file/folder.
		 * @param[in]	overwriteExisting	(optional) If true, any existing file/folder at the new location will be
		 *									overwritten, otherwise an exception will be thrown if a file/folder already exists.
		 */
		static void move(const Path& oldPath, const Path& newPath, bool overwriteExisting = true);

		/**
		 * Makes a copy of a file or a folder in the specified path.
		 *
		 * @param[in]	oldPath			 	Full path to the old file/folder.
		 * @param[in]	newPath			 	Full path to the new file/folder.
		 * @param[in]	overwriteExisting	(optional) If true, any existing file/folder at the new location will be
		 *									overwritten, otherwise an exception will be thrown if a file/folder already exists.
		 */
		static void copy(const Path& oldPath, const Path& newPath, bool overwriteExisting = true);

		/**
		 * Creates a folder at the specified path.
		 *
		 * @param[in]	fullPath	Full path to a full folder to create.
		 */
		static void createDir(const Path& fullPath);

		/**
		 * Returns true if a file or a folder exists at the specified path.
		 *
		 * @param[in]	fullPath	Full path to a file or folder.
		 */
		static bool exists(const Path& fullPath);

		/**
		 * Returns true if a file exists at the specified path.
		 *
		 * @param[in]	fullPath	Full path to a file or folder.
		 */
		static bool isFile(const Path& fullPath);

		/**
		 * Returns true if a folder exists at the specified path.
		 *
		 * @param[in]	fullPath	Full path to a file or folder.
		 */
		static bool isDirectory(const Path& fullPath);

		/**
		 * Returns all files or folders located in the specified folder.
		 *
		 * @param[in]	dirPath			Full path to the folder to retrieve children files/folders from.
		 * @param[out]	files	   		Full paths to all files located directly in specified folder.
		 * @param[out]	directories		Full paths to all folders located directly in specified folder.
		 */
		static void getChildren(const Path& dirPath, Vector<Path>& files, Vector<Path>& directories);

		/**
		 * Iterates over all files and directories in the specified folder and calls the provided callback when a
		 * file/folder is iterated over.
		 *
		 * @param[in]	dirPath			Directory over which to iterate
		 * @param[in]	fileCallback	Callback to call whenever a file is found. If callback returns false iteration stops. Can be null.
		 * @param[in]	dirCallback		Callback to call whenever a directory is found. If callback returns false iteration stops. Can be null.
		 * @param[in]	recursive		If false then only the direct children of the provided folder will be iterated over,
		 *								and if true then child directories will be recursively visited as well.
		 * @return						True if iteration finished iterating over all files/folders, or false if it was
		 *								interrupted by a callback returning false.
		 */
		static bool iterate(const Path& dirPath, std::function<bool(const Path&)> fileCallback,
			std::function<bool(const Path&)> dirCallback = nullptr, bool recursive = true);

		/**
		 * Returns the last modified time of a file or a folder at the specified path.
		 *
		 * @param[in]	fullPath	Full path to a file or a folder.
		 */
		static std::time_t getLastModifiedTime(const Path& fullPath);

		/** Returns the path to the currently working directory. */
		static Path getWorkingDirectoryPath();

		/** Returns the path to a directory where temporary files may be stored. */
		static Path getTempDirectoryPath();

	private:
		/** Copy a single file. Internal function used by copy(). */
		static void copyFile(const Path& oldPath, const Path& newPath);
		/** Remove a single file. Internal function used by remove(). */
		static void removeFile(const Path& path);
		/** Move a single file. Internal function used by move(). */
		static void moveFile(const Path& oldPath, const Path& newPath);

	};

	/** @} */
}