// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0

#include "registryaccess.h"

#include <QApplication>

#include <QDir>
#include <QTextStream>

namespace RegistryAccess {

static QString winErrorMessage(unsigned long error)
{
    QString rc = QString::fromLatin1("#%1: ").arg(error);
    char16_t *lpMsgBuf;

    const int len = FormatMessage(
            FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
            nullptr, error, 0, (LPTSTR)&lpMsgBuf, 0, nullptr);
    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, nullptr, &type, nullptr, &size);
    if (rc != ERROR_SUCCESS) {
        *errorMessage = msgRegistryOperationFailed("read", valueName, msgFunctionFailed("RegQueryValueEx1", rc));
        return false;
    }
    auto dataC = new BYTE[size + 1];
    // Will be Utf16 in case of a string
    rc = RegQueryValueEx(handle, valueName, nullptr, &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 char16_t *>(data.data()));
    return true;
}

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

    REGSAM accessRights = KEY_READ;
    if (readWrite)
         accessRights |= KEY_SET_VALUE;
    switch (mode) {
    case RegistryAccess::DefaultAccessMode:
        break;
    case RegistryAccess::Registry32Mode:
        accessRights |= KEY_WOW64_32KEY;
        break;
    case RegistryAccess::Registry64Mode:
        accessRights |= KEY_WOW64_64KEY;
        break;
    }
    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