// Copyright (C) 2002-2012 Nikolaus Gebhardt
// This file is part of the "Irrlicht Engine".
// For conditions of distribution and use, see copyright notice in irrlicht.h

#include "CFileSystem.h"
#include "IReadFile.h"
#include "IWriteFile.h"
#include "CZipReader.h"
#include "CFileList.h"
#include "CReadFile.h"
#include "CMemoryFile.h"
#include "CLimitReadFile.h"
#include "CWriteFile.h"
#include "coreutil.h"
#include <list>

#if defined(__STRICT_ANSI__)
#error Compiling with __STRICT_ANSI__ not supported. g++ does set this when compiling with -std=c++11 or -std=c++0x. Use instead -std=gnu++11 or -std=gnu++0x. Or use -U__STRICT_ANSI__ to disable strict ansi.
#endif

#if defined(_IRR_WINDOWS_API_)
#include <direct.h> // for _chdir
#include <io.h>     // for _access
#include <tchar.h>
#elif (defined(_IRR_POSIX_API_) || defined(_IRR_OSX_PLATFORM_) || defined(_IRR_ANDROID_PLATFORM_))
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <climits>
#include <sys/types.h>
#include <dirent.h>
#include <sys/stat.h>
#include <unistd.h>
#elif defined(_IRR_EMSCRIPTEN_PLATFORM_)
#include <unistd.h>
#endif

namespace irr
{
namespace io
{

//! constructor
CFileSystem::CFileSystem()
{
	setFileListSystem(FILESYSTEM_NATIVE);
	//! reset current working directory
	getWorkingDirectory();

	ArchiveLoader.push_back(new CArchiveLoaderZIP(this));
}

//! destructor
CFileSystem::~CFileSystem()
{
	for (auto *it : ArchiveLoader) {
		it->drop();
	}
}

//! opens a file for read access
IReadFile *CFileSystem::createAndOpenFile(const io::path &filename)
{
	if (filename.empty())
		return 0;

	// Create the file using an absolute path so that it matches
	// the scheme used by CNullDriver::getTexture().
	return CReadFile::createReadFile(getAbsolutePath(filename));
}

//! Creates an IReadFile interface for treating memory like a file.
IReadFile *CFileSystem::createMemoryReadFile(const void *memory, s32 len,
		const io::path &fileName, bool deleteMemoryWhenDropped)
{
	if (!memory)
		return 0;
	else
		return new CMemoryReadFile(memory, len, fileName, deleteMemoryWhenDropped);
}

//! Creates an IReadFile interface for reading files inside files
IReadFile *CFileSystem::createLimitReadFile(const io::path &fileName,
		IReadFile *alreadyOpenedFile, long pos, long areaSize)
{
	if (!alreadyOpenedFile)
		return 0;
	else
		return new CLimitReadFile(alreadyOpenedFile, pos, areaSize, fileName);
}

//! Creates an IReadFile interface for treating memory like a file.
IWriteFile *CFileSystem::createMemoryWriteFile(void *memory, s32 len,
		const io::path &fileName, bool deleteMemoryWhenDropped)
{
	if (!memory)
		return 0;
	else
		return new CMemoryWriteFile(memory, len, fileName, deleteMemoryWhenDropped);
}

//! Opens a file for write access.
IWriteFile *CFileSystem::createAndWriteFile(const io::path &filename, bool append)
{
	return CWriteFile::createWriteFile(filename, append);
}

//! Adds an external archive loader to the engine.
void CFileSystem::addArchiveLoader(IArchiveLoader *loader)
{
	if (!loader)
		return;

	loader->grab();
	ArchiveLoader.push_back(loader);
}

//! Returns the total number of archive loaders added.
u32 CFileSystem::getArchiveLoaderCount() const
{
	return ArchiveLoader.size();
}

//! Gets the archive loader by index.
IArchiveLoader *CFileSystem::getArchiveLoader(u32 index) const
{
	if (index < ArchiveLoader.size())
		return ArchiveLoader[index];
	else
		return 0;
}

//! Returns the string of the current working directory
const io::path &CFileSystem::getWorkingDirectory()
{
	EFileSystemType type = FileSystemType;

	if (type != FILESYSTEM_NATIVE) {
		type = FILESYSTEM_VIRTUAL;
	} else {
#if defined(_IRR_WINDOWS_API_)
		fschar_t tmp[_MAX_PATH];
		_getcwd(tmp, _MAX_PATH);
		WorkingDirectory[FILESYSTEM_NATIVE] = tmp;
		WorkingDirectory[FILESYSTEM_NATIVE].replace('\\', '/');
#endif

#if (defined(_IRR_POSIX_API_) || defined(_IRR_OSX_PLATFORM_))

		// getting the CWD is rather complex as we do not know the size
		// so try it until the call was successful
		// Note that neither the first nor the second parameter may be 0 according to POSIX

		u32 pathSize = 256;
		char *tmpPath = new char[pathSize];
		while ((pathSize < (1 << 16)) && !(getcwd(tmpPath, pathSize))) {
			delete[] tmpPath;
			pathSize *= 2;
			tmpPath = new char[pathSize];
		}
		if (tmpPath) {
			WorkingDirectory[FILESYSTEM_NATIVE] = tmpPath;
			delete[] tmpPath;
		}
#endif

		WorkingDirectory[type].validate();
	}

	return WorkingDirectory[type];
}

//! Changes the current Working Directory to the given string.
bool CFileSystem::changeWorkingDirectoryTo(const io::path &newDirectory)
{
	bool success = false;

	if (FileSystemType != FILESYSTEM_NATIVE) {
		WorkingDirectory[FILESYSTEM_VIRTUAL] = newDirectory;
		// is this empty string constant really intended?
		flattenFilename(WorkingDirectory[FILESYSTEM_VIRTUAL], _IRR_TEXT(""));
		success = true;
	} else {
		WorkingDirectory[FILESYSTEM_NATIVE] = newDirectory;

#if defined(_MSC_VER)
		success = (_chdir(newDirectory.c_str()) == 0);
#else
		success = (chdir(newDirectory.c_str()) == 0);
#endif
	}

	return success;
}

io::path CFileSystem::getAbsolutePath(const io::path &filename) const
{
	if (filename.empty())
		return filename;
#if defined(_IRR_WINDOWS_API_)
	fschar_t *p = 0;
	fschar_t fpath[_MAX_PATH];
	p = _fullpath(fpath, filename.c_str(), _MAX_PATH);
	core::stringc tmp(p);
	tmp.replace('\\', '/');
	return tmp;
#elif (defined(_IRR_POSIX_API_) || defined(_IRR_OSX_PLATFORM_))
	c8 *p = 0;
	c8 fpath[4096];
	fpath[0] = 0;
	p = realpath(filename.c_str(), fpath);
	if (!p) {
		// content in fpath is unclear at this point
		if (!fpath[0]) { // seems like fpath wasn't altered, use our best guess
			io::path tmp(filename);
			return flattenFilename(tmp);
		} else
			return io::path(fpath);
	}
	if (filename[filename.size() - 1] == '/')
		return io::path(p) + _IRR_TEXT("/");
	else
		return io::path(p);
#else
	return io::path(filename);
#endif
}

//! returns the directory part of a filename, i.e. all until the first
//! slash or backslash, excluding it. If no directory path is prefixed, a '.'
//! is returned.
io::path CFileSystem::getFileDir(const io::path &filename) const
{
	// find last forward or backslash
	s32 lastSlash = filename.findLast('/');
	const s32 lastBackSlash = filename.findLast('\\');
	lastSlash = lastSlash > lastBackSlash ? lastSlash : lastBackSlash;

	if ((u32)lastSlash < filename.size())
		return filename.subString(0, lastSlash);
	else
		return _IRR_TEXT(".");
}

//! returns the base part of a filename, i.e. all except for the directory
//! part. If no directory path is prefixed, the full name is returned.
io::path CFileSystem::getFileBasename(const io::path &filename, bool keepExtension) const
{
	// find last forward or backslash
	s32 lastSlash = filename.findLast('/');
	const s32 lastBackSlash = filename.findLast('\\');
	lastSlash = core::max_(lastSlash, lastBackSlash);

	// get number of chars after last dot
	s32 end = 0;
	if (!keepExtension) {
		// take care to search only after last slash to check only for
		// dots in the filename
		end = filename.findLast('.');
		if (end == -1 || end < lastSlash)
			end = 0;
		else
			end = filename.size() - end;
	}

	if ((u32)lastSlash < filename.size())
		return filename.subString(lastSlash + 1, filename.size() - lastSlash - 1 - end);
	else if (end != 0)
		return filename.subString(0, filename.size() - end);
	else
		return filename;
}

//! flatten a path and file name for example: "/you/me/../." becomes "/you"
io::path &CFileSystem::flattenFilename(io::path &directory, const io::path &root) const
{
	directory.replace('\\', '/');
	if (directory.lastChar() != '/')
		directory.append('/');

	io::path dir;
	io::path subdir;

	s32 lastpos = 0;
	s32 pos = 0;
	bool lastWasRealDir = false;

	while ((pos = directory.findNext('/', lastpos)) >= 0) {
		subdir = directory.subString(lastpos, pos - lastpos + 1);

		if (subdir == _IRR_TEXT("../")) {
			if (lastWasRealDir) {
				deletePathFromPath(dir, 2);
				lastWasRealDir = (dir.size() != 0);
			} else {
				dir.append(subdir);
				lastWasRealDir = false;
			}
		} else if (subdir == _IRR_TEXT("/")) {
			dir = root;
		} else if (subdir != _IRR_TEXT("./")) {
			dir.append(subdir);
			lastWasRealDir = true;
		}

		lastpos = pos + 1;
	}
	directory = dir;
	return directory;
}

//! Get the relative filename, relative to the given directory
path CFileSystem::getRelativeFilename(const path &filename, const path &directory) const
{
	if (filename.empty() || directory.empty())
		return filename;

	io::path path1, file, ext;
	core::splitFilename(getAbsolutePath(filename), &path1, &file, &ext);
	io::path path2(getAbsolutePath(directory));
	std::list<io::path> list1, list2;
	path1.split(list1, _IRR_TEXT("/\\"), 2);
	path2.split(list2, _IRR_TEXT("/\\"), 2);
	std::list<io::path>::const_iterator it1, it2;
	it1 = list1.begin();
	it2 = list2.begin();

#if defined(_IRR_WINDOWS_API_)
	fschar_t partition1 = 0, partition2 = 0;
	io::path prefix1, prefix2;
	if (it1 != list1.end())
		prefix1 = *it1;
	if (it2 != list2.end())
		prefix2 = *it2;
	if (prefix1.size() > 1 && prefix1[1] == _IRR_TEXT(':'))
		partition1 = core::locale_lower(prefix1[0]);
	if (prefix2.size() > 1 && prefix2[1] == _IRR_TEXT(':'))
		partition2 = core::locale_lower(prefix2[0]);

	// must have the same prefix or we can't resolve it to a relative filename
	if (partition1 != partition2) {
		return filename;
	}
#endif

	for (; it1 != list1.end() && it2 != list2.end()
#if defined(_IRR_WINDOWS_API_)
			&& (io::path(*it1).make_lower() == io::path(*it2).make_lower())
#else
			&& (*it1 == *it2)
#endif
					;) {
		++it1;
		++it2;
	}
	path1 = _IRR_TEXT("");
	for (; it2 != list2.end(); ++it2)
		path1 += _IRR_TEXT("../");
	while (it1 != list1.end()) {
		path1 += *it1++;
		path1 += _IRR_TEXT('/');
	}
	path1 += file;
	if (ext.size()) {
		path1 += _IRR_TEXT('.');
		path1 += ext;
	}
	return path1;
}

//! Sets the current file systen type
EFileSystemType CFileSystem::setFileListSystem(EFileSystemType listType)
{
	EFileSystemType current = FileSystemType;
	FileSystemType = listType;
	return current;
}

//! Creates a list of files and directories in the current working directory
IFileList *CFileSystem::createFileList()
{
	CFileList *r = 0;
	io::path Path = getWorkingDirectory();
	Path.replace('\\', '/');
	if (!Path.empty() && Path.lastChar() != '/')
		Path.append('/');

	//! Construct from native filesystem
	if (FileSystemType == FILESYSTEM_NATIVE) {
// --------------------------------------------
//! Windows version
#ifdef _IRR_WINDOWS_API_

		r = new CFileList(Path, true, false);

		// intptr_t is optional but supported by MinGW since 2007 or earlier.
		intptr_t hFile;
		struct _tfinddata_t c_file;
		if ((hFile = _tfindfirst(_T("*"), &c_file)) != (intptr_t)(-1L)) {
			do {
				r->addItem(Path + c_file.name, 0, c_file.size, (_A_SUBDIR & c_file.attrib) != 0, 0);
			} while (_tfindnext(hFile, &c_file) == 0);

			_findclose(hFile);
		}

#endif

// --------------------------------------------
//! Linux version
#if (defined(_IRR_POSIX_API_) || defined(_IRR_OSX_PLATFORM_))

		r = new CFileList(Path, false, false);

		r->addItem(Path + _IRR_TEXT(".."), 0, 0, true, 0);

		//! We use the POSIX compliant methods instead of scandir
		DIR *dirHandle = opendir(Path.c_str());
		if (dirHandle) {
			struct dirent *dirEntry;
			while ((dirEntry = readdir(dirHandle))) {
				u32 size = 0;
				bool isDirectory = false;

				if ((strcmp(dirEntry->d_name, ".") == 0) ||
						(strcmp(dirEntry->d_name, "..") == 0)) {
					continue;
				}
				struct stat buf;
				if (stat(dirEntry->d_name, &buf) == 0) {
					size = buf.st_size;
					isDirectory = S_ISDIR(buf.st_mode);
				}
#if !defined(_IRR_SOLARIS_PLATFORM_) && !defined(__CYGWIN__) && !defined(__HAIKU__)
				// only available on some systems
				else {
					isDirectory = dirEntry->d_type == DT_DIR;
				}
#endif

				r->addItem(Path + dirEntry->d_name, 0, size, isDirectory, 0);
			}
			closedir(dirHandle);
		}
#endif
	} else {
		//! create file list for the virtual filesystem
		r = new CFileList(Path, false, false);

		//! add relative navigation
		SFileListEntry e2;
		SFileListEntry e3;

		//! PWD
		r->addItem(Path + _IRR_TEXT("."), 0, 0, true, 0);

		//! parent
		r->addItem(Path + _IRR_TEXT(".."), 0, 0, true, 0);
	}

	if (r)
		r->sort();
	return r;
}

//! Creates an empty filelist
IFileList *CFileSystem::createEmptyFileList(const io::path &path, bool ignoreCase, bool ignorePaths)
{
	return new CFileList(path, ignoreCase, ignorePaths);
}

//! determines if a file exists and would be able to be opened.
bool CFileSystem::existFile(const io::path &filename) const
{
#if defined(_MSC_VER)
	return (_access(filename.c_str(), 0) != -1);
#elif defined(F_OK)
	return (access(filename.c_str(), F_OK) != -1);
#else
	return (access(filename.c_str(), 0) != -1);
#endif
}

//! creates a filesystem which is able to open files from the ordinary file system,
//! and out of zipfiles, which are able to be added to the filesystem.
IFileSystem *createFileSystem()
{
	return new CFileSystem();
}

} // end namespace irr
} // end namespace io
