/*

 * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

#include "WinSysInfo.h"

#include "FileUtils.h"

#include "WinErrorHandling.h"

namespace SysInfo {

tstring getTempDir() {

    std::vector<TCHAR> buffer(MAX_PATH);

    DWORD res = GetTempPath(static_cast<DWORD>(buffer.size()), buffer.data());

    if (res > buffer.size()) {

        buffer.resize(res);

        GetTempPath(static_cast<DWORD>(buffer.size()), buffer.data());

    }

    return FileUtils::removeTrailingSlash(buffer.data());

}

namespace {

template <class Func>

tstring getSystemDirImpl(Func func, const std::string& label) {

    std::vector<TCHAR> buffer(MAX_PATH);

    for (int i=0; i<2; i++) {

        DWORD res = func(buffer.data(), static_cast<DWORD>(buffer.size()));

        if (!res) {

            JP_THROW(SysError(label + " failed", func));

        }

        if (res < buffer.size()) {

            return FileUtils::removeTrailingSlash(buffer.data());

        }

        buffer.resize(res + 1);

    }

    JP_THROW("Unexpected reply from" + label);

}

} // namespace

tstring getSystem32Dir() {

    return getSystemDirImpl(GetSystemDirectory, "GetSystemDirectory");

}

tstring getWIPath() {

    return FileUtils::mkpath() << getSystem32Dir() << _T("msiexec.exe");

}

namespace {

tstring getModulePath(HMODULE h)

{

    std::vector<TCHAR> buf(MAX_PATH);

    DWORD len = 0;

    while (true) {

        len = GetModuleFileName(h, buf.data(), (DWORD)buf.size());

        if (len < buf.size()) {

            break;

        }

        // buffer is too small, increase it

        buf.resize(buf.size() * 2);

    }

    if (len == 0) {

        // error occured

        JP_THROW(SysError("GetModuleFileName failed", GetModuleFileName));

    }

    return tstring(buf.begin(), buf.begin() + len);

}

} // namespace

tstring getProcessModulePath() {

    return getModulePath(NULL);

}

HMODULE getCurrentModuleHandle()

{

    // get module handle for the address of this function

    LPCWSTR address = reinterpret_cast<LPCWSTR>(getCurrentModuleHandle);

    HMODULE hmodule = NULL;

    if (!GetModuleHandleExW(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS | GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,

                            address, &hmodule))

    {

        JP_THROW(SysError(tstrings::any() << "GetModuleHandleExW failed", GetModuleHandleExW));

    }

    return hmodule;

}

tstring getCurrentModulePath()

{

    return getModulePath(getCurrentModuleHandle());

}

namespace {

tstring getEnvVariableImpl(const tstring& name, bool* errorOccured=0) {

    std::vector<TCHAR> buf(10);

    SetLastError(ERROR_SUCCESS);

    const DWORD size = GetEnvironmentVariable(name.c_str(), buf.data(),

                                                            DWORD(buf.size()));

    if (GetLastError() == ERROR_ENVVAR_NOT_FOUND) {

        if (errorOccured) {

            *errorOccured = true;

            return tstring();

        }

        JP_THROW(SysError(tstrings::any() << "GetEnvironmentVariable("

            << name << ") failed. Variable not set", GetEnvironmentVariable));

    }

    if (size > buf.size()) {

        buf.resize(size);

        GetEnvironmentVariable(name.c_str(), buf.data(), DWORD(buf.size()));

        if (GetLastError() != ERROR_SUCCESS) {

            if (errorOccured) {

                *errorOccured = true;

                return tstring();

            }

            JP_THROW(SysError(tstrings::any() << "GetEnvironmentVariable("

                            << name << ") failed", GetEnvironmentVariable));

        }

    }

    if (errorOccured) {

        *errorOccured = false;

    }

    return tstring(buf.data());

}

} // namespace

tstring getEnvVariable(const tstring& name) {

    return getEnvVariableImpl(name);

}

tstring getEnvVariable(const std::nothrow_t&, const tstring& name,

                                                    const tstring& defValue) {

    bool errorOccured = false;

    const tstring reply = getEnvVariableImpl(name, &errorOccured);

    if (errorOccured) {

        return defValue;

    }

    return reply;

}

bool isEnvVariableSet(const tstring& name) {

    TCHAR unused[1];

    SetLastError(ERROR_SUCCESS);

    GetEnvironmentVariable(name.c_str(), unused, _countof(unused));

    return GetLastError() != ERROR_ENVVAR_NOT_FOUND;

}

} // end of namespace SysInfo