/*=========================================================================

  Program:   Visualization Toolkit

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

Initial version and concept gratefully provided by Klaus Steinhorst

Returns 0 if the system supports OpenGL 3.2 or later.

If provided a -v argument then it will display a message box
with additional system information.

=========================================================================*/

#include <iostream>
#include <sstream>
#include <string>
#include <vector>

#include <windows.h>

#include <GL/gl.h>

class CheckOpenGLVersion
{
public:
  CheckOpenGLVersion(HINSTANCE hInstance);
  bool hasVersion_3_2();
  std::string version;
  std::string renderer;
  std::string vendor;

private:
  HINSTANCE hInstance;
  PIXELFORMATDESCRIPTOR pixelFormatDescriptor;
  int glMajorVersion = 1;
  int glMinorVersion = 0;
};

typedef HGLRC(WINAPI* PFNWGLCREATECONTEXTATTRIBSARBPROC)(
  HDC hDC, HGLRC hShareContext, const int* attribList);
#define WGL_CONTEXT_MAJOR_VERSION_ARB 0x2091
#define WGL_CONTEXT_MINOR_VERSION_ARB 0x2092
#define WGL_CONTEXT_FLAGS_ARB 0x2094
#define GL_MAJOR_VERSION 0x821B
#define GL_MINOR_VERSION 0x821C

CheckOpenGLVersion::CheckOpenGLVersion(HINSTANCE hInst)
  : hInstance(hInst)
{
  pixelFormatDescriptor = { sizeof(PIXELFORMATDESCRIPTOR), 1,
    PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER, // Flags
    PFD_TYPE_RGBA, // The kind of framebuffer. RGBA or palette.
    32,            // Colordepth of the framebuffer.
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    24, // Number of bits for the depthbuffer
    8,  // Number of bits for the stencilbuffer
    0,  // Number of Aux buffers in the framebuffer.
    PFD_MAIN_PLANE, 0, 0, 0, 0 };

  WNDCLASSA wc = { 0 };
  wc.lpfnWndProc = DefWindowProc;
  wc.hInstance = hInstance;
  wc.hbrBackground = reinterpret_cast<HBRUSH>(COLOR_BACKGROUND);
  wc.lpszClassName = "oglversioncheck";
  wc.style = CS_OWNDC;
  if (!RegisterClass(&wc))
  {
    return;
  }
  HWND windowHandle = CreateWindowA(wc.lpszClassName, "openglversioncheck", WS_OVERLAPPEDWINDOW, 0,
    0, 640, 480, 0, 0, this->hInstance, 0);

  if (windowHandle != nullptr)
  {
    HDC ourWindowHandleToDeviceContext = GetDC(windowHandle);

    int letWindowsChooseThisPixelFormat;
    letWindowsChooseThisPixelFormat =
      ChoosePixelFormat(ourWindowHandleToDeviceContext, &this->pixelFormatDescriptor);
    SetPixelFormat(ourWindowHandleToDeviceContext, letWindowsChooseThisPixelFormat,
      &this->pixelFormatDescriptor);

    HGLRC ourOpenGLRenderingContext = wglCreateContext(ourWindowHandleToDeviceContext);

    wglMakeCurrent(ourWindowHandleToDeviceContext, ourOpenGLRenderingContext);

    this->version = std::string(reinterpret_cast<const char*>(glGetString(GL_VERSION)));
    this->renderer = std::string(reinterpret_cast<const char*>(glGetString(GL_RENDERER)));
    this->vendor = std::string(reinterpret_cast<const char*>(glGetString(GL_VENDOR)));

    // create a context
    PFNWGLCREATECONTEXTATTRIBSARBPROC wglCreateContextAttribsARB =
      reinterpret_cast<PFNWGLCREATECONTEXTATTRIBSARBPROC>(
        wglGetProcAddress("wglCreateContextAttribsARB"));
    if (wglCreateContextAttribsARB)
    {
      // we believe that these later versions are all compatible with
      // OpenGL 3.2 so get a more recent context if we can.
      int attemptedVersions[] = { 4, 5, 4, 4, 4, 3, 4, 2, 4, 1, 4, 0, 3, 3, 3, 2 };
      int iContextAttribs[] = {
        WGL_CONTEXT_MAJOR_VERSION_ARB, 3, WGL_CONTEXT_MINOR_VERSION_ARB, 2, WGL_CONTEXT_FLAGS_ARB,
        0,
        0 // End of attributes list
      };
      HGLRC contextId = nullptr;
      for (int i = 0; i < 8 && !contextId; i++)
      {
        iContextAttribs[1] = attemptedVersions[i * 2];
        iContextAttribs[3] = attemptedVersions[i * 2 + 1];
        contextId = wglCreateContextAttribsARB(ourWindowHandleToDeviceContext, 0, iContextAttribs);
      }
      if (contextId)
      {
        wglMakeCurrent(ourWindowHandleToDeviceContext, contextId);

        glGetIntegerv(GL_MAJOR_VERSION, &this->glMajorVersion);
        glGetIntegerv(GL_MINOR_VERSION, &this->glMinorVersion);

        wglDeleteContext(contextId);
        contextId = nullptr;
      }
    }

    wglDeleteContext(ourOpenGLRenderingContext);
  }
}

bool CheckOpenGLVersion::hasVersion_3_2()
{
  // version string should have format "4.5.0 <vendorstuff>"
  // so it is enough to parse the 0th and 2nd char
  int majorCheck = 3;
  int minorCheck = 2;

  if (this->glMajorVersion > majorCheck)
  {
    return true;
  }

  if (this->glMajorVersion == majorCheck && this->glMinorVersion >= minorCheck)
  {
    return true;
  }

  return false;
}

int CALLBACK WinMain(_In_ HINSTANCE hInstance, _In_ HINSTANCE /*hPrevInstance*/,
  _In_ LPSTR lpCmdLine, _In_ int /*nCmdShow*/)
{
  CheckOpenGLVersion checker(hInstance);

  bool result = checker.hasVersion_3_2();

  std::string cline = lpCmdLine;
  if (cline.find("-v") != std::string::npos)
  {
    std::ostringstream toString;
    toString << "A working 3.2 version of OpenGL was " << (!result ? " not" : "")
             << " found from version " << checker.version << " with renderer " << checker.renderer
             << " from vendor " << checker.vendor;
    MessageBox(nullptr, toString.str().c_str(), "VTK OpenGL Version Test", MB_OK);
  }

  PostQuitMessage(0);

  return (result ? 0 : 1);
}