/****************************************************************************
**
** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of Qt Creator.
**
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia.  For licensing terms and
** conditions see http://qt.digia.com/licensing.  For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Digia gives you certain additional
** rights.  These rights are described in the Digia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
****************************************************************************/

#include "registryaccess.h"

#include <QApplication>

#include <QDir>
#include <QTextStream>

namespace RegistryAccess {

static QString winErrorMessage(unsigned long error)
{
    QString rc = QString::fromLatin1("#%1: ").arg(error);
    ushort *lpMsgBuf;

    const int len = FormatMessage(
            FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
            NULL, error, 0, (LPTSTR)&lpMsgBuf, 0, NULL);
    if (len) {
       rc = QString::fromUtf16(lpMsgBuf, len);
        LocalFree(lpMsgBuf);
    } else {
        rc += QString::fromLatin1("<unknown error>");
    }
    return rc;
}

QString msgFunctionFailed(const char *f, unsigned long error)
{
    return QString::fromLatin1("'%1' failed: %2").arg(QLatin1String(f), winErrorMessage(error));
}

static bool registryReadBinaryKey(HKEY handle, // HKEY_LOCAL_MACHINE, etc.
                                  const WCHAR *valueName,
                                  QByteArray *data,
                                  QString *errorMessage)
{
    data->clear();
    DWORD type;
    DWORD size;
    // get size and retrieve
    LONG rc = RegQueryValueEx(handle, valueName, 0, &type, 0, &size);
    if (rc != ERROR_SUCCESS) {
        *errorMessage = msgRegistryOperationFailed("read", valueName, msgFunctionFailed("RegQueryValueEx1", rc));
        return false;
    }
    BYTE *dataC = new BYTE[size + 1];
    // Will be Utf16 in case of a string
    rc = RegQueryValueEx(handle, valueName, 0, &type, dataC, &size);
    if (rc != ERROR_SUCCESS) {
        *errorMessage = msgRegistryOperationFailed("read", valueName, msgFunctionFailed("RegQueryValueEx2", rc));
        return false;
    }
    *data = QByteArray(reinterpret_cast<const char*>(dataC), size);
    delete [] dataC;
    return true;
}

bool registryReadStringKey(HKEY handle, // HKEY_LOCAL_MACHINE, etc.
                           const WCHAR *valueName,
                           QString *s,
                           QString *errorMessage)
{
    QByteArray data;
    if (!registryReadBinaryKey(handle, valueName, &data, errorMessage))
        return false;
    data += '\0';
    data += '\0';
    *s = QString::fromUtf16(reinterpret_cast<const unsigned short*>(data.data()));
    return true;
}

bool openRegistryKey(HKEY category, // HKEY_LOCAL_MACHINE, etc.
                     const WCHAR *key,
                     bool readWrite,
                     HKEY *keyHandle,
                     QString *errorMessage)
{
    Q_UNUSED(debuggerRegistryKeyC);  // avoid warning from MinGW

    REGSAM accessRights = KEY_READ;
    if (readWrite)
         accessRights |= KEY_SET_VALUE;
    const LONG rc = RegOpenKeyEx(category, key, 0, accessRights, keyHandle);
    if (rc != ERROR_SUCCESS) {
        *errorMessage = msgFunctionFailed("RegOpenKeyEx", rc);
        if (readWrite)
            *errorMessage += QLatin1String("You need administrator privileges to edit the registry.");
        return false;
    }
    return true;
}

// Installation helpers: Format the debugger call with placeholders for PID and event
// '"[path]\qtcdebugger" [-wow] %ld %ld'.

QString debuggerCall(const QString &additionalOption)
{
    QString rc;
    QTextStream str(&rc);
    str << '"' << QDir::toNativeSeparators(QApplication::applicationDirPath() + QLatin1Char('/')
                                           + QLatin1String(debuggerApplicationFileC) + QLatin1String(".exe")) << '"';
    if (!additionalOption.isEmpty())
        str << ' ' << additionalOption;
    str << " %ld %ld";
    return rc;
}

bool isRegistered(HKEY handle, const QString &call, QString *errorMessage, QString *oldDebugger)
{
    QString registeredDebugger;
    registryReadStringKey(handle, debuggerRegistryValueNameC, &registeredDebugger, errorMessage);
    if (oldDebugger)
        *oldDebugger = registeredDebugger;
    return !registeredDebugger.compare(call, Qt::CaseInsensitive);
}

} // namespace RegistryAccess