//
// File_WIN32U.cpp
//
// Library: Foundation
// Package: Filesystem
// Module:  File
//
// Copyright (c) 2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier:	BSL-1.0
//


#include "Poco/File_WIN32U.h"
#include "Poco/Exception.h"
#include "Poco/Path.h"
#include "Poco/String.h"
#include "Poco/UnicodeConverter.h"
#include "Poco/UnWindows.h"
#include <vector>


namespace Poco {


class FileHandle
{
public:
	FileHandle(const std::string& path, const std::wstring& upath, DWORD access, DWORD share, DWORD disp)
	{
		_h = ::CreateFileW(upath.c_str(), access, share, 0, disp, 0, 0);
		if (_h == INVALID_HANDLE_VALUE)
		{
			FileImpl::handleLastErrorImpl(path);
		}
	}

	~FileHandle()
	{
		if (_h != INVALID_HANDLE_VALUE) ::CloseHandle(_h);
	}

	HANDLE get() const
	{
		return _h;
	}

private:
	HANDLE _h;
};


namespace {

/// Return cached PATHEXT extensions as a vector of strings.
/// Initialized once at first call.
/// Thread-safe: static initialization is thread-safe in C++11+, and
/// the returned reference remains valid for the lifetime of the program.
const std::vector<std::string>& getPathExtensions()
{
	static const std::vector<std::string> extensions = []()
	{
		std::vector<std::string> result;
		const std::string pathExt = Environment::get("PATHEXT", ".EXE");
		const StringTokenizer st(pathExt, ";",
			StringTokenizer::TOK_IGNORE_EMPTY | StringTokenizer::TOK_TRIM);

		for (const auto& ext : st)
		{
			result.push_back(ext);
		}
		return result;
	}();

	return extensions;
}

} // anonymous namespace


FileImpl::FileImpl()
{
}


FileImpl::FileImpl(const std::string& path): _path(path)
{
	std::string::size_type n = _path.size();
	if (n > 1 && (_path[n - 1] == '\\' || _path[n - 1] == '/') && !((n == 3 && _path[1]==':')))
	{
		_path.resize(n - 1);
	}
	convertPath(_path, _upath);
}


FileImpl::~FileImpl()
{
}


void FileImpl::swapImpl(FileImpl& file)
{
	std::swap(_path, file._path);
	std::swap(_upath, file._upath);
}


void FileImpl::setPathImpl(const std::string& path)
{
	_path = path;
	std::string::size_type n = _path.size();
	if (n > 1 && (_path[n - 1] == '\\' || _path[n - 1] == '/') && !((n == 3 && _path[1]==':')))
	{
		_path.resize(n - 1);
	}
	convertPath(_path, _upath);
}

std::string FileImpl::getExecutablePathImpl() const
{
	if (_path.empty()) return {};

	std::wstring uname;
	UnicodeConverter::toUTF16(_path, uname);

	auto searchPath = [&uname](const WCHAR* ext) -> std::string
	{
		static constexpr std::size_t INITIAL_BUF_LEN {256};
		std::vector<WCHAR> buf(INITIAL_BUF_LEN);
		DWORD len = ::SearchPathW(NULL, uname.c_str(), ext, buf.size(), buf.data(), NULL);
		if (len == 0)
		{
			// Not found
			return {};
		}
		if (len > INITIAL_BUF_LEN)
		{
			// Buffer too small, resize and retry
			buf.resize(len);
			len = ::SearchPathW(NULL, uname.c_str(), ext, buf.size(), buf.data(), NULL);
		}
		if (len == 0)
		{
			// Failure (very unlikely)
			return {};
		}
		std::string result;
		UnicodeConverter::toUTF8(buf.data(), len, result);
		return result;
	};

	// First, try the filename as-is (validate executability to reject non-executable matches)
	std::string result = searchPath(NULL);
	if (!result.empty() && canExecuteImpl(result))
		return result;

	// Try each PATHEXT extension via SearchPathW
	const auto& extensions = getPathExtensions();

	for (const auto& ext : extensions)
	{
		std::wstring wExt;
		UnicodeConverter::toUTF16(ext, wExt);
		result = searchPath(wExt.c_str());
		// SearchPathW ignores the extension when the filename contains
		// a path separator; verify the result actually has the extension.
		if (!result.empty() && icompare(result, result.size() - ext.size(), ext.size(), ext) == 0)
			return result;
	}

	return {};
}


bool FileImpl::existsImpl() const
{
	poco_assert (!_path.empty());

	DWORD attr = ::GetFileAttributesW(_upath.c_str());
	if (attr == INVALID_FILE_ATTRIBUTES)
	{
		switch (::GetLastError())
		{
		case ERROR_FILE_NOT_FOUND:
		case ERROR_PATH_NOT_FOUND:
		case ERROR_INVALID_DRIVE:
			return false;
		default:
			handleLastErrorImpl(_path);
		}
	}
	return true;
}


bool FileImpl::canReadImpl() const
{
	poco_assert (!_path.empty());

	DWORD attr = ::GetFileAttributesW(_upath.c_str());
	if (attr == INVALID_FILE_ATTRIBUTES)
	{
		switch (::GetLastError())
		{
		case ERROR_ACCESS_DENIED:
			return false;
		default:
			handleLastErrorImpl(_path);
		}
	}
	return true;
}


bool FileImpl::canWriteImpl() const
{
	poco_assert (!_path.empty());

	DWORD attr = ::GetFileAttributesW(_upath.c_str());
	if (attr == INVALID_FILE_ATTRIBUTES)
		handleLastErrorImpl(_path);
	return (attr & FILE_ATTRIBUTE_READONLY) == 0;
}


bool FileImpl::canExecuteImpl(const std::string& absolutePath) const
{
	Path p(absolutePath);
	std::string ext = p.getExtension();
	if (ext.empty()) return false;

	const auto& extensions = getPathExtensions();

	std::string dotExt = "." + ext;
	for (const auto& entry : extensions)
	{
		if (icompare(dotExt, entry) == 0)
			return true;
	}

	return false;
}


bool FileImpl::isFileImpl() const
{
	return !isDirectoryImpl() && !isDeviceImpl();
}


bool FileImpl::isDirectoryImpl() const
{
	poco_assert (!_path.empty());

	DWORD attr = ::GetFileAttributesW(_upath.c_str());
	if (attr == INVALID_FILE_ATTRIBUTES)
		handleLastErrorImpl(_path);
	return (attr & FILE_ATTRIBUTE_DIRECTORY) != 0;
}


bool FileImpl::isLinkImpl() const
{
	poco_assert (!_path.empty());

	DWORD attr = ::GetFileAttributesW(_upath.c_str());
	if (attr == INVALID_FILE_ATTRIBUTES)
		handleLastErrorImpl(_path);
	return (attr & FILE_ATTRIBUTE_DIRECTORY) == 0 && (attr & FILE_ATTRIBUTE_REPARSE_POINT) != 0;
}


bool FileImpl::isDeviceImpl() const
{
	return
		_path.compare(0, 4, "\\\\.\\") == 0 ||
		icompare(_path, "CON") == 0 ||
		icompare(_path, "PRN") == 0 ||
		icompare(_path, "AUX") == 0 ||
		icompare(_path, "NUL") == 0 ||
		( (icompare(_path, 0, 3, "LPT") == 0 || icompare(_path, 0, 3, "COM") == 0) &&
		   _path.size() == 4 &&
		   _path[3] > 0x30   &&
		   isdigit(_path[3])
		);
}


bool FileImpl::isHiddenImpl() const
{
	poco_assert (!_path.empty());

	DWORD attr = ::GetFileAttributesW(_upath.c_str());
	if (attr == INVALID_FILE_ATTRIBUTES)
		handleLastErrorImpl(_path);
	return (attr & FILE_ATTRIBUTE_HIDDEN) != 0;
}


Timestamp FileImpl::createdImpl() const
{
	poco_assert (!_path.empty());

	WIN32_FILE_ATTRIBUTE_DATA fad;
	if (::GetFileAttributesExW(_upath.c_str(), GetFileExInfoStandard, &fad) == 0)
		handleLastErrorImpl(_path);
	return Timestamp::fromFileTimeNP(fad.ftCreationTime.dwLowDateTime, fad.ftCreationTime.dwHighDateTime);
}


Timestamp FileImpl::getLastModifiedImpl() const
{
	poco_assert (!_path.empty());

	WIN32_FILE_ATTRIBUTE_DATA fad;
	if (::GetFileAttributesExW(_upath.c_str(), GetFileExInfoStandard, &fad) == 0)
		handleLastErrorImpl(_path);
	return Timestamp::fromFileTimeNP(fad.ftLastWriteTime.dwLowDateTime, fad.ftLastWriteTime.dwHighDateTime);
}


void FileImpl::setLastModifiedImpl(const Timestamp& ts)
{
	poco_assert (!_path.empty());

	UInt32 low;
	UInt32 high;
	ts.toFileTimeNP(low, high);
	FILETIME ft;
	ft.dwLowDateTime  = low;
	ft.dwHighDateTime = high;
	FileHandle fh(_path, _upath, FILE_WRITE_ATTRIBUTES, FILE_SHARE_READ | FILE_SHARE_WRITE, OPEN_EXISTING);
	if (::SetFileTime(fh.get(), 0, &ft, &ft) == 0)
		handleLastErrorImpl(_path);
}


FileImpl::FileSizeImpl FileImpl::getSizeImpl() const
{
	poco_assert (!_path.empty());

	WIN32_FILE_ATTRIBUTE_DATA fad;
	if (::GetFileAttributesExW(_upath.c_str(), GetFileExInfoStandard, &fad) == 0)
		handleLastErrorImpl(_path);
	LARGE_INTEGER li;
	li.LowPart  = fad.nFileSizeLow;
	li.HighPart = fad.nFileSizeHigh;
	return li.QuadPart;
}


void FileImpl::setSizeImpl(FileSizeImpl size)
{
	poco_assert (!_path.empty());

	FileHandle fh(_path, _upath, GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, OPEN_EXISTING);
	LARGE_INTEGER li;
	li.QuadPart = size;
	if (::SetFilePointer(fh.get(), li.LowPart, &li.HighPart, FILE_BEGIN) == INVALID_SET_FILE_POINTER)
		handleLastErrorImpl(_path);
	if (::SetEndOfFile(fh.get()) == 0)
		handleLastErrorImpl(_path);
}


void FileImpl::setWriteableImpl(bool flag)
{
	poco_assert (!_path.empty());

	DWORD attr = ::GetFileAttributesW(_upath.c_str());
	if (attr == -1)
		handleLastErrorImpl(_path);
	if (flag)
		attr &= ~FILE_ATTRIBUTE_READONLY;
	else
		attr |= FILE_ATTRIBUTE_READONLY;
	if (::SetFileAttributesW(_upath.c_str(), attr) == 0)
		handleLastErrorImpl(_path);
}


void FileImpl::setExecutableImpl(bool flag)
{
	// not supported
}


void FileImpl::copyToImpl(const std::string& path, int options) const
{
	poco_assert (!_path.empty());

	std::wstring upath;
	convertPath(path, upath);
	if (::CopyFileW(_upath.c_str(), upath.c_str(), (options & OPT_FAIL_ON_OVERWRITE_IMPL) != 0) == 0)
	{
		// CopyFileW() function cannot copy Alternate Data Streams
		FileHandle fhIn(_path, _upath, GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE, OPEN_EXISTING);
		FileHandle fhOut(path, upath, GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, 
			((options & OPT_FAIL_ON_OVERWRITE_IMPL) != 0) ? CREATE_NEW : OPEN_ALWAYS);
		char buf[65536];
		DWORD dwRead = sizeof(buf), dwWritten = 0;
		while (dwRead == sizeof(buf))
		{
			if (!ReadFile(fhIn.get(), buf, sizeof(buf), &dwRead, nullptr))
				handleLastErrorImpl(_path);
			if (!WriteFile(fhOut.get(), buf, dwRead, &dwWritten, nullptr))
				handleLastErrorImpl(_path);
		}
		SetEndOfFile(fhOut.get());
	}
}


void FileImpl::renameToImpl(const std::string& path, int options)
{
	poco_assert (!_path.empty());

	std::wstring upath;
	convertPath(path, upath);
	if (options & OPT_FAIL_ON_OVERWRITE_IMPL) {
		if (::MoveFileExW(_upath.c_str(), upath.c_str(), 0) == 0)
			handleLastErrorImpl(_path);
	} else {
		if (::MoveFileExW(_upath.c_str(), upath.c_str(), MOVEFILE_REPLACE_EXISTING) == 0)
			handleLastErrorImpl(_path);
	}
}


void FileImpl::linkToImpl(const std::string& path, int type) const
{
	poco_assert (!_path.empty());

	std::wstring upath;
	convertPath(path, upath);

	if (type == 0)
	{
		if (::CreateHardLinkW(upath.c_str(), _upath.c_str(), nullptr) == 0)
			handleLastErrorImpl(_path);
	}
	else
	{
#if _WIN32_WINNT >= 0x0600 && defined(SYMBOLIC_LINK_FLAG_DIRECTORY)
		DWORD flags = 0;
		if (isDirectoryImpl()) flags |= SYMBOLIC_LINK_FLAG_DIRECTORY;
#ifdef SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE
		flags |= SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE;
#endif
		if (::CreateSymbolicLinkW(upath.c_str(), _upath.c_str(), flags) == 0)
			handleLastErrorImpl(_path);
#else
		throw Poco::NotImplementedException("Symbolic link support not available in used version of the Windows SDK");
#endif
	}
}


void FileImpl::removeImpl()
{
	poco_assert (!_path.empty());

	if (isDirectoryImpl())
	{
		if (::RemoveDirectoryW(_upath.c_str()) == 0)
			handleLastErrorImpl(_path);
	}
	else
	{
		if (::DeleteFileW(_upath.c_str()) == 0)
			handleLastErrorImpl(_path);
	}
}


bool FileImpl::createFileImpl(bool createDirectories)
{
	poco_assert (!_path.empty());

	if(createDirectories) {
		Path p(_path);
		p.makeDirectory();
	}

	HANDLE hFile = ::CreateFileW(_upath.c_str(), GENERIC_WRITE, 0, 0, CREATE_NEW, 0, 0);
	if (hFile != INVALID_HANDLE_VALUE)
	{
		::CloseHandle(hFile);
		return true;
	}
	else if (::GetLastError() == ERROR_FILE_EXISTS)
		return false;
	else
		handleLastErrorImpl(_path);
	return false;
}


bool FileImpl::createDirectoryImpl()
{
	poco_assert (!_path.empty());

	if (existsImpl() && isDirectoryImpl())
		return false;
	if (::CreateDirectoryW(_upath.c_str(), 0) == 0)
		handleLastErrorImpl(_path);
	return true;
}


FileImpl::FileSizeImpl FileImpl::totalSpaceImpl() const
{
	poco_assert(!_path.empty());

	ULARGE_INTEGER space;
	if (!::GetDiskFreeSpaceExW(_upath.c_str(), nullptr, &space, nullptr))
		handleLastErrorImpl(_path);
	return space.QuadPart;
}


FileImpl::FileSizeImpl FileImpl::usableSpaceImpl() const
{
	poco_assert(!_path.empty());

	ULARGE_INTEGER space;
	if (!::GetDiskFreeSpaceExW(_upath.c_str(), &space, nullptr, nullptr))
		handleLastErrorImpl(_path);
	return space.QuadPart;
}


FileImpl::FileSizeImpl FileImpl::freeSpaceImpl() const
{
	poco_assert(!_path.empty());

	ULARGE_INTEGER space;
	if (!::GetDiskFreeSpaceExW(_upath.c_str(), nullptr, nullptr, &space))
		handleLastErrorImpl(_path);
	return space.QuadPart;
}


void FileImpl::handleLastErrorImpl(const std::string& path)
{
	DWORD err = ::GetLastError();
	switch (err)
	{
	case ERROR_FILE_NOT_FOUND:
		throw FileNotFoundException(path, err);
	case ERROR_PATH_NOT_FOUND:
	case ERROR_BAD_NETPATH:
	case ERROR_CANT_RESOLVE_FILENAME:
	case ERROR_INVALID_DRIVE:
		throw PathNotFoundException(path, err);
	case ERROR_NOT_READY:
		throw FileNotReadyException(path, err);
	case ERROR_ACCESS_DENIED:
		throw FileAccessDeniedException(path, err);
	case ERROR_ALREADY_EXISTS:
	case ERROR_FILE_EXISTS:
		throw FileExistsException(path, err);
	case ERROR_INVALID_NAME:
	case ERROR_DIRECTORY:
	case ERROR_FILENAME_EXCED_RANGE:
	case ERROR_BAD_PATHNAME:
		throw PathSyntaxException(path, err);
	case ERROR_FILE_READ_ONLY:
		throw FileReadOnlyException(path, err);
	case ERROR_CANNOT_MAKE:
		throw CreateFileException(path, err);
	case ERROR_DIR_NOT_EMPTY:
		throw DirectoryNotEmptyException(path, err);
	case ERROR_WRITE_FAULT:
		throw WriteFileException(path, err);
	case ERROR_READ_FAULT:
		throw ReadFileException(path, err);
	case ERROR_SHARING_VIOLATION:
		throw FileException("sharing violation", path, err);
	case ERROR_LOCK_VIOLATION:
		throw FileException("lock violation", path, err);
	case ERROR_HANDLE_EOF:
		throw ReadFileException("EOF reached", path, err);
	case ERROR_HANDLE_DISK_FULL:
	case ERROR_DISK_FULL:
		throw WriteFileException("disk is full", path, err);
	case ERROR_NEGATIVE_SEEK:
		throw FileException("negative seek", path, err);
	default:
		throw FileException(path, err);
	}
}


void FileImpl::convertPath(const std::string& utf8Path, std::wstring& utf16Path)
{
	UnicodeConverter::toUTF16(utf8Path, utf16Path);
	if (utf16Path.length() > 0 && utf16Path.back() == L':')
	{
		// If the path only has disk letter, we must make sure it ends with backslash!
		// Or it will be failed to call Windows API ::GetFileAttributesW().
		// For example:
		//   DWORD dw = ::GetFileAttributesW(L"\\\\?\\C:"); // dw == -1
		utf16Path.push_back(L'\\');
	}
	if (utf16Path.size() > MAX_PATH - 12) // Note: CreateDirectory has a limit of MAX_PATH - 12 (room for 8.3 file name)
	{
		if (utf16Path[0] == '\\' || utf16Path[1] == ':')
		{
			if (utf16Path.compare(0, 4, L"\\\\?\\", 4) != 0)
			{
				if (utf16Path[1] == '\\')
					//	Starting with  "\\\\server\\etc\\etc..."
					//	Form resulting "\\\\?\\UNC\\server\\etc\\etc..."
					utf16Path.insert(1, L"\\?\\UNC", 6);
				else
					//	Starting with  "C:\\etc\\etc..."
					//	Form resulting "\\\\?\\C:\\etc\\etc..."
					utf16Path.insert(0, L"\\\\?\\", 4);
			}
		}
	}
	else
	{
		if (utf16Path.compare(0, 8, L"\\\\?\\UNC\\", 8) == 0)
		{
			utf16Path.erase(1, 6);	// leave "\\\\" at beginning
		}
		else
		if (utf16Path.compare(0, 4, L"\\\\?\\", 4) == 0)
		{
			utf16Path.erase(0, 4);
		}
	}
}

} // namespace Poco
