#pragma region CPL License
/*
Nuclex Native Framework
Copyright (C) 2002-2023 Nuclex Development Labs

This library is free software; you can redistribute it and/or
modify it under the terms of the IBM Common Public License as
published by the IBM Corporation; either version 1.0 of the
License, or (at your option) any later version.

This library 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
IBM Common Public License for more details.

You should have received a copy of the IBM Common Public
License along with this library
*/
#pragma endregion // CPL License

#ifndef NUCLEX_PLATFORM_HARDWARE_WINDOWSREGISTRYCPUINFOREADER_H
#define NUCLEX_PLATFORM_HARDWARE_WINDOWSREGISTRYCPUINFOREADER_H

#include "Nuclex/Platform/Config.h"

#if defined(NUCLEX_PLATFORM_WINDOWS)

#include <string> // for std::string
#include <cstddef> // for std::size_t
#include <memory> // for std::shared_ptr

namespace Nuclex { namespace Platform { namespace Tasks {

  // ------------------------------------------------------------------------------------------- //

  class CancellationWatcher;

  // ------------------------------------------------------------------------------------------- //

}}} // namespace Nuclex::Platform::Tasks

namespace Nuclex { namespace Platform { namespace Hardware {

  // ------------------------------------------------------------------------------------------- //

  /// <summary>Reads processor names and base frequencies from the Windows registry</summary>
  /// <remarks>
  ///   <para>
  ///     The location this information is pulled from
  ///     (HKLM\HARDWARE\DESCRIPTION\System\CentralProcessor\<n>\) is not an officially
  ///     documented place to find it. So future Windows versions could theoretically
  ///     stop storing it there or place random dummy data in its place. Theoretically.
  ///   </para>
  ///   <para>
  ///     There are applications out in the wild that access this registry path, there are
  ///     StackOverflow posts recommending it and Wine/Proton provide the information here,
  ///     too, so practically, we're pretty safe. And just in case, we do paranoid checking
  ///     for anything that looks off and fall back to the officially sanctioned way to
  ///     query for this information (COM + WMI, *barf*).
  ///   </para>
  /// </remarks>
  class WindowsRegistryCpuInfoReader {

    /// <summary>
    ///   Signature for the callback function invoked by <see cref="TryQueryCpuInfos" />
    /// </summary>
    public: typedef void CallbackFunction(
      void *userPointer,
      std::size_t processorIndex,
      const std::string &name,
      double frequencyInMhz
    );

    /// <summary>
    ///   Attempts to read informations about processors from the Windows registry
    /// </summary>
    /// <param name="processorCount">Number of processors to query</param>
    /// <param name="userPointer">Will be passed to the callback unmodified</param>
    /// <param name="callback">
    ///   Callback that will be invoked for each processor, provided with the
    ///   user pointer, processor index, processor name and base frequency in GHz
    /// </param>
    /// <param name="canceller">Allows the enumeration to be cancelled early</param>
    /// <returns>
    ///   True if all informations were in the expected place, complete and in
    ///   the expected format and the callback was invoked for each processor.
    /// </returns>
    public: static bool TryReadCpuInfos(
      std::size_t processorCount,
      void *userPointer,
      CallbackFunction *callback,
      const std::shared_ptr<const Tasks::CancellationWatcher> &canceller
    );

  };

  // ------------------------------------------------------------------------------------------- //

}}} // namespace Nuclex::Platform::Hardware

#endif // defined(NUCLEX_PLATFORM_WINDOWS)

#endif // NUCLEX_PLATFORM_HARDWARE_WINDOWSREGISTRYCPUINFOREADER_H