// Copyright (c) 2012- PPSSPP Project.

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, version 2.0 or later versions.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License 2.0 for more details.

// A copy of the GPL 2.0 should have been included with the program.
// If not, see http://www.gnu.org/licenses/

// Official git repository and contact information can be found at
// https://github.com/hrydgard/ppsspp and http://www.ppsspp.org/.

#include "util/text/utf8.h"
#include "file/file_util.h"
#include "Common/FileUtil.h"
#include "Core/FileLoaders/LocalFileLoader.h"

#ifndef _WIN32
#include <fcntl.h>
#endif

LocalFileLoader::LocalFileLoader(const std::string &filename)
	: filesize_(0), filename_(filename) {

#ifndef _WIN32

	fd_ = open(filename.c_str(), O_RDONLY | O_CLOEXEC);
	if (fd_ == -1) {
		return;
	}
	off64_t off = lseek64(fd_, 0, SEEK_END);
	filesize_ = off;
	lseek64(fd_, 0, SEEK_SET);

#else // !_WIN32

	const DWORD access = GENERIC_READ, share = FILE_SHARE_READ, mode = OPEN_EXISTING, flags = FILE_ATTRIBUTE_NORMAL;
#if PPSSPP_PLATFORM(UWP)
	handle_ = CreateFile2(ConvertUTF8ToWString(filename).c_str(), access, share, mode, nullptr);
#else
	handle_ = CreateFile(ConvertUTF8ToWString(filename).c_str(), access, share, nullptr, mode, flags, nullptr);
#endif
	if (handle_ == INVALID_HANDLE_VALUE) {
		return;
	}
	FILE_STANDARD_INFO info;
	if (GetFileInformationByHandleEx(handle_, FileStandardInfo, &info, sizeof(info)) == 0) {
		return;
	}
	filesize_ = info.EndOfFile.QuadPart;

#endif // !_WIN32

}

LocalFileLoader::~LocalFileLoader() {
#ifndef _WIN32
	if (fd_ != -1) {
		close(fd_);
	}
#else
	if (handle_ != INVALID_HANDLE_VALUE) {
		CloseHandle(handle_);
	}
#endif
}

bool LocalFileLoader::Exists() {
	// If we couldn't open it for reading, we say it does not exist.
#ifndef _WIN32
	if (fd_ != -1 || IsDirectory()) {
#else
	if (handle_ != INVALID_HANDLE_VALUE || IsDirectory()) {
#endif
		FileInfo info;
		return getFileInfo(filename_.c_str(), &info);
	}
	return false;
}

bool LocalFileLoader::IsDirectory() {
	FileInfo info;
	if (getFileInfo(filename_.c_str(), &info)) {
		return info.isDirectory;
	}
	return false;
}

s64 LocalFileLoader::FileSize() {
	return filesize_;
}

std::string LocalFileLoader::Path() const {
	return filename_;
}

size_t LocalFileLoader::ReadAt(s64 absolutePos, size_t bytes, size_t count, void *data, Flags flags) {
#ifndef _WIN32
	return pread64(fd_, data, bytes * count, absolutePos) / bytes;
#else
	DWORD read = -1;
	OVERLAPPED offset = { 0 };
	offset.Offset = (DWORD)(absolutePos & 0xffffffff);
	offset.OffsetHigh = (DWORD)((absolutePos & 0xffffffff00000000) >> 32);
	auto result = ReadFile(handle_, data, bytes * count, &read, &offset);
	return result == TRUE ? (size_t)read / bytes : -1;
#endif
}