#include "DisplayClass.h"
#include "gl.h"

#ifdef _WIN32
#else
#include <iostream>
#include <X11/X.h>
#include <GL/glx.h>
#include <sys/time.h>
#include <unistd.h>
#endif

#define MIN_FRAME_DELTA 16
#define DEFAULT_WIDTH 640
#define DEFAULT_HEIGHT 640

void initGL(bool multisample);
void resize(int width, int height);

void initGL(bool multisample) {
  glClearColor(0.0, 0.0, 0.0, 1.0);
  glClearDepth(1.0);
  glEnable(GL_DEPTH_TEST);
  glDepthFunc(GL_LEQUAL);

  //glEnable(GL_BLEND);
  //glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

#ifndef _WIN32
  if(multisample)
    glEnable(GL_MULTISAMPLE_ARB);
#endif

  resize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
}

void resize(int width, int height)
{
  if(height==0)
  {
    height=1;
  }

  glViewport(0, 0, width, height);

  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  gluPerspective(50.0f,(GLfloat)width/(GLfloat)height, 0.1, 1000);

  glMatrixMode(GL_MODELVIEW);
}


#ifdef _WIN32

bool WGLInit(HINSTANCE hInstance, HWND *hWnd, HDC *hDC, HGLRC *hRC);
void WGLUninit(HWND hWnd, HDC hDC, HGLRC hRC);
LRESULT CALLBACK wndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam);

bool WGLInit(HINSTANCE hInstance, HWND *hWnd, HDC *hDC, HGLRC *hRC) {
  WNDCLASS wc;
  wc.style = CS_HREDRAW | CS_VREDRAW | CS_OWNDC;
  wc.lpfnWndProc = (WNDPROC)wndProc;
  wc.cbClsExtra = 0;
  wc.cbWndExtra = 0;
  wc.hInstance = hInstance;
  wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
  wc.hCursor = LoadCursor(NULL, IDC_ARROW);
  wc.hbrBackground = 0;
  wc.lpszMenuName = 0;
  wc.lpszClassName = "3D";

  if (!RegisterClass(&wc))
  {
    MessageBox(0, "Failed To Register The Window Class.", "ERROR", MB_OK|MB_ICONEXCLAMATION);
    return false;             // Exit And Return FALSE
  }

  DWORD dwExStyle = WS_EX_APPWINDOW | WS_EX_WINDOWEDGE;
  DWORD dwStyle = WS_OVERLAPPEDWINDOW;

  RECT windowRect;
  windowRect.left = 0;
  windowRect.right = DEFAULT_WIDTH;
  windowRect.top = 0;
  windowRect.bottom = DEFAULT_HEIGHT;

  AdjustWindowRectEx(&windowRect, dwStyle, FALSE, dwExStyle);

  *hWnd = CreateWindowEx(dwExStyle, "3D" /* Class Name */, "3D" /* Title*/, WS_CLIPSIBLINGS | WS_CLIPCHILDREN | dwStyle,
                        0, 0, windowRect.right-windowRect.left, windowRect.bottom-windowRect.top, 0, 0, hInstance, 0);
  if(!*hWnd)
  {
    MessageBox(0, "Window Creation Error.", "ERROR", MB_OK|MB_ICONEXCLAMATION);
    return false;
  }

  static PIXELFORMATDESCRIPTOR pfd =
  {
      sizeof(PIXELFORMATDESCRIPTOR), // Size Of This Pixel Format Descriptor
      1,                             // Version Number
      PFD_DRAW_TO_WINDOW |           // Format Must Support Window
      PFD_SUPPORT_OPENGL |           // Format Must Support OpenGL
      PFD_DOUBLEBUFFER,              // Must Support Double Buffering
      PFD_TYPE_RGBA,                 // Request An RGBA Format
      16,                            // Select Our Color Depth
      0, 0, 0, 0, 0, 0,              // Color Bits Ignored
      0,                             // No Alpha Buffer
      0,                             // Shift Bit Ignored
      0,                             // No Accumulation Buffer
      0, 0, 0, 0,                    // Accumulation Bits Ignored
      16,                            // 16Bit Z-Buffer (Depth Buffer)
      0,                             // No Stencil Buffer
      0,                             // No Auxiliary Buffer
      PFD_MAIN_PLANE,                // Main Drawing Layer
      0,                             // Reserved
      0, 0, 0                        // Layer Masks Ignored
  };

  *hDC=GetDC(*hWnd);
  if (!*hDC)
  {
    WGLUninit(*hWnd, 0, 0);
    MessageBox(0, "Can't Create A GL Device Context.", "ERROR", MB_OK|MB_ICONEXCLAMATION);
    return false;
  }

  GLuint pixelFormat = ChoosePixelFormat(*hDC, &pfd);
  if(!pixelFormat)
  {
    WGLUninit(*hWnd, *hDC, 0);
    MessageBox(0, "Can't Find A Suitable PixelFormat.", "ERROR", MB_OK|MB_ICONEXCLAMATION);
    return false;
  }

  if(!SetPixelFormat(*hDC, pixelFormat, &pfd))
  {
    WGLUninit(*hWnd, *hDC, 0);
    MessageBox(0, "Can't Set The PixelFormat.", "ERROR", MB_OK|MB_ICONEXCLAMATION);
    return false;
  }

  *hRC=wglCreateContext(*hDC);
  if(!*hRC)
  {
    WGLUninit(*hWnd, *hDC, 0);
    MessageBox(0, "Can't Create A GL Rendering Context.", "ERROR", MB_OK|MB_ICONEXCLAMATION);
    return false;
  }

  if(!wglMakeCurrent(*hDC, *hRC))
  {
    WGLUninit(*hWnd, *hDC, *hRC);
    MessageBox(0, "Can't Activate The GL Rendering Context.", "ERROR", MB_OK|MB_ICONEXCLAMATION);
    return false;
  }

  ShowWindow(*hWnd, SW_SHOW);
  SetForegroundWindow(*hWnd);
  SetFocus(*hWnd);

  return true;
}

void WGLUninit(HWND hWnd, HDC hDC, HGLRC hRC) {
  wglMakeCurrent(0, 0);

  if(hRC)
    wglDeleteContext(hRC);

  if(hDC)
    ReleaseDC(hWnd, hDC);

  if(hWnd)
    DestroyWindow(hWnd);
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
  HWND hWnd = 0;
  HDC hDC = 0;
  HGLRC hRC = 0;

  if(!WGLInit(hInstance, &hWnd, &hDC, &hRC))
  {
    return 0;
  }

  initGL(false);

  bool running = true;
  MSG msg;

  while(running)
  {
    unsigned long delta = 0;
    unsigned long ticks = GetTickCount();

    while(PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
    {
      if(msg.message == WM_QUIT)
      {
        running = false;
        break;
      }
      else              // If Not, Deal With Window Messages
      {
        TranslateMessage(&msg);       // Translate The Message
        DispatchMessage(&msg);        // Dispatch The Message
      }
    }

    delta = GetTickCount()-ticks;

    if(delta < MIN_FRAME_DELTA) {
      Sleep(MIN_FRAME_DELTA - delta);
      delta = GetTickCount()-ticks;
    }

    ticks += delta;

    static DisplayClass render;
    render.renderScene(delta);
    SwapBuffers(hDC);
  }

  WGLUninit(hWnd, hDC, hRC);
  return msg.wParam;
}

LRESULT CALLBACK wndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam) {
  switch(uMsg) {
    case WM_CLOSE:
      PostQuitMessage(0);
      return 0;

    case WM_SIZE:
      resize(LOWORD(lParam), HIWORD(lParam));
      return 0;

    default:
      return DefWindowProc(hWnd, uMsg, wParam, lParam);
  }
}

#else

bool GLXinit(Display *disp, Atom windele, Window *wnd, GLXContext *gc, bool *multisample) {
  static const int msAttributeList[] = {GLX_RENDER_TYPE, GLX_RGBA_BIT,
                                        GLX_DRAWABLE_TYPE, GLX_WINDOW_BIT,
                                        GLX_X_RENDERABLE, True,
                                        GLX_DOUBLEBUFFER, True,
                                        GLX_DEPTH_SIZE, 1,
                                        GLX_SAMPLE_BUFFERS, 1,
                                        GLX_SAMPLES, 4,
                                        None};

  static const int attributeList[] = {GLX_RENDER_TYPE, GLX_RGBA_BIT,
                                      GLX_DRAWABLE_TYPE, GLX_WINDOW_BIT,
                                      GLX_X_RENDERABLE, True,
                                      GLX_DOUBLEBUFFER, True,
                                      GLX_DEPTH_SIZE, 1,
                                      None};
  
  bool ok = false;
  *multisample = true;

  int nElements;
  GLXFBConfig *fbConfig = glXChooseFBConfig(disp, DefaultScreen(disp), msAttributeList, &nElements);
  if(!fbConfig || !nElements) {
    if(fbConfig) {
      XFree(fbConfig);
    }

    *multisample = false;
    fbConfig = glXChooseFBConfig(disp, DefaultScreen(disp), attributeList, &nElements);
  }

  if(fbConfig && nElements) {
    XVisualInfo *vi = glXGetVisualFromFBConfig(disp, *fbConfig);

    if(vi) {
      Colormap cmap = XCreateColormap(disp, RootWindow(disp, vi->screen), vi->visual, AllocNone);
      XSetWindowAttributes swa;
      swa.colormap = cmap;
      swa.border_pixel = 0;
      swa.event_mask = /*PointerMotionMask | KeyPressMask | KeyReleaseMask | ButtonPressMask | ButtonReleaseMask*/0;

      *wnd = XCreateWindow(disp, RootWindow(disp, vi->screen), 0, 0, DEFAULT_WIDTH, DEFAULT_HEIGHT, 0, vi->depth, InputOutput,
          vi->visual, CWBorderPixel|CWColormap|CWEventMask, &swa);

      XClassHint chint;
      chint.res_name = const_cast<char*>("3D");
      chint.res_class = const_cast<char*>("3d");
      XSetClassHint(disp, *wnd, &chint);

      char *str = const_cast<char*>("3D");
      XTextProperty name;
      if(XStringListToTextProperty(&str, 1, &name) != 0)
      {
        XSetWMName(disp, *wnd, &name);
        XFree(name.value);
      }

      XSetWMProtocols(disp, *wnd, &windele, 1);

      XMapWindow(disp, *wnd);

      *gc = glXCreateContext(disp, vi, NULL, True);

      glXMakeCurrent(disp, *wnd, *gc);

      ok = true;

      XFree(vi);
    }
  }

  if(fbConfig)
    XFree(fbConfig);

  XSync(disp, 0);

  return ok;
}

int main() {
  Display *disp = XOpenDisplay(0);
  Atom windele = XInternAtom(disp, "WM_DELETE_WINDOW", False);
  Window wnd;
  GLXContext gc;

  bool multisample;
  if(!GLXinit(disp, windele, &wnd, &gc, &multisample))
    return 1;
  initGL(multisample);

  GLint samples;
  glGetIntegerv(GL_SAMPLES, &samples);
  std::cerr << "Using " << samples << " samples" << std::endl;

  bool running = true;
  
  unsigned long delta = 0;
  unsigned long frames = 0, tocks = 0;
  
  struct timeval tv;
  gettimeofday(&tv, NULL);
  unsigned long ticks = tv.tv_usec;

  while(running) {
    while(XPending(disp)) {
      XEvent event;
      XNextEvent(disp, &event);
      switch(event.type) {
        case ClientMessage:
          if(static_cast<Atom>(event.xclient.data.l[0]) == windele)
            running = false;
          break;
      }
    }

    if(!running) break;

    static DisplayClass render;
    render.renderScene(delta);

    glXSwapBuffers(disp, wnd);
    XSync(disp, 0);

    gettimeofday(&tv, NULL);
    delta = ((tv.tv_usec + 1000000 - ticks)%1000000)/1000;

    if(delta < MIN_FRAME_DELTA) {
      usleep((MIN_FRAME_DELTA-delta)*1000);

      gettimeofday(&tv, NULL);
      delta = ((tv.tv_usec + 1000000 - ticks)%1000000)/1000;
    }

    ticks = (ticks + delta*1000) % 1000000;

    frames++;
    tocks += delta*1000;
    if(tocks > 1000000) {
      std::cerr << frames << std::endl;
      frames = 0;
      tocks -= 1000000;
    }
  }

  XDestroyWindow(disp, wnd);
  glXDestroyContext(disp, gc);
  XCloseDisplay(disp);

  return 0;
}

#endif