/**
  * @RDE_HEADER@
  * Small wrapper to automatically start thp_viewer
  * $Id$
  * $HeadURL$
  * $Author$
  * Created by Christian Ehrlicher, SLSE, 2016-02-29
  */

#include <windows.h>
#include <gl/gl.h>
#include <gl/glu.h>

static void* getGLExtensionFuncPtr(const char *funcName, const char *fallbackFuncName)
{
  void* ptr = wglGetProcAddress(funcName);
  if (ptr)
    return ptr;
  return wglGetProcAddress(fallbackFuncName);
}

static int checkOpenGL(HWND hWnd)
{
  HDC hDC = GetDC( hWnd );

  PIXELFORMATDESCRIPTOR pfd;
  ZeroMemory( &pfd, sizeof( pfd ) );
  pfd.nSize = sizeof( pfd );
  pfd.nVersion = 1;
  pfd.dwFlags  = PFD_DRAW_TO_WINDOW |
                 PFD_SUPPORT_OPENGL |
                 PFD_DOUBLEBUFFER   |
                 PFD_SWAP_EXCHANGE;
  pfd.iPixelType = PFD_TYPE_RGBA;
  pfd.cColorBits = 32;
  pfd.cRedBits   = 8;
  pfd.cGreenBits = 8;
  pfd.cBlueBits  = 8;
  pfd.cAlphaBits = 8;
  pfd.cDepthBits = 0;
  pfd.iLayerType = PFD_MAIN_PLANE;
  int iFormat = ChoosePixelFormat( hDC, &pfd );
  if( !SetPixelFormat( hDC, iFormat, &pfd ) ) {
    DWORD dw = GetLastError();
    int ret = MessageBox(NULL,
               L"Your system does not support some mandatory OpenGL Functions.\nThe THP-Viewer may not display all things correct!\nDo you really want to start the THP-viewer?",
               L"THP-Viewer startup",
               MB_ICONWARNING|MB_YESNO);
    if(ret == IDNO) {
      ReleaseDC( hWnd, hDC );
     return 1;
    }
  }

  HGLRC hRC = wglCreateContext( hDC );

  DWORD dw = wglMakeCurrent( hDC, hRC );
  void *_glCompressedTexImage2D = getGLExtensionFuncPtr( "glCompressedTexImage2D", "glCompressedTexImage2DARB" );
  if(!_glCompressedTexImage2D) {
    int ret = MessageBox(NULL,
               L"Your system does not support the mandatory OpenGL Function glCompressedTexImage2D.\nThe THP-Viewer may not display all things correct!\nDo you really want to start the THP-viewer?",
               L"THP-Viewer startup",
               MB_ICONWARNING|MB_YESNO);
    if(ret == IDNO) {
      wglDeleteContext( hRC );
      ReleaseDC( hWnd, hDC );
      return 1;
    }
  }

  wglDeleteContext( hRC );
  ReleaseDC( hWnd, hDC );

  return 0;
}

static int startThpViewer(HINSTANCE hInstance)
{
  TCHAR fn[MAX_PATH*10];
  DWORD len = GetModuleFileName(hInstance, fn, sizeof(fn));
  
  for(int i = len - 1; i >= 0; --i) {
    if(fn[i] == '\\')
      break;
    fn[i] = '\0';
  }
  wcscat(fn, L"thp\\thp_viewer.exe");

  STARTUPINFO si; ZeroMemory(&si, sizeof(si));
  PROCESS_INFORMATION pi; ZeroMemory(&pi, sizeof(pi));
  si.cb = sizeof(si);
  
  DWORD ret = CreateProcess(fn,
                            NULL,   // lpCommandLine
                            NULL,   // lpProcessAttributes
                            NULL,   // lpThreadAttributes
                            NULL,   // bInheritHandles
                            0,      // dwCreationFlags
                            NULL,   // lpEnvironment
                            NULL,   // lpCurrentDirectory
                            &si,    // lpStartupInfo
                            &pi);   // lpProcessInformation

  if(ret == 0) {
    MessageBox(NULL,
               L"Error starting the THP-Viewer!",
               L"THP-Viewer startup",
               MB_ICONWARNING|MB_OK);
    return 1;
  }
  // Wait until child process exits.
  WaitForSingleObject( pi.hProcess, INFINITE );

  // Close process and thread handles. 
  CloseHandle( pi.hProcess );
  CloseHandle( pi.hThread );

  return 0;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
  return DefWindowProc( hWnd, message, wParam, lParam );
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
               LPSTR lpCmdLine, int nCmdShow)
{
  WNDCLASS wc;
  ZeroMemory( &wc, sizeof(wc) );
  // register window class
  wc.style = CS_OWNDC;
  wc.lpfnWndProc = WndProc;
  wc.hInstance = hInstance;
  wc.lpszClassName = L"THP_Viewer_startup";
  RegisterClass( &wc );

  // create main window
  HWND hWnd = CreateWindow(L"THP_Viewer_startup",
                           L"THP-Viewer startup", 
                           WS_CAPTION | WS_POPUPWINDOW,
                           0, 0, 256, 256,
                           NULL, NULL, hInstance, NULL );

  int iRet = checkOpenGL(hWnd);
  if(iRet != 0)
    return iRet;
  return startThpViewer(hInstance);
}