#include <windows.h>
#include <Wingdi.h>
#include <GL/gl.h>

#include "example.h"

const char g_szClassName[] = "OpenGLWindowClass";

HDC hdc;
HGLRC hglrc;
HWND hwnd;
int done = 0;

int screenw, screenh;

void SysShutdown (void)
{
    done = 1;
    exampleFinish();
    wglMakeCurrent(hdc, NULL);
    wglDeleteContext(hglrc);
    PostQuitMessage(0);
}

void setPixelFormat()
{
    PIXELFORMATDESCRIPTOR pfd =
    {
        sizeof(PIXELFORMATDESCRIPTOR),
        1,
        PFD_DRAW_TO_WINDOW|PFD_SUPPORT_OPENGL|PFD_DOUBLEBUFFER,
        PFD_TYPE_RGBA,
        32,
        0,0,0,0,0,0,0,0,0,0,0,0,0, // useles parameters
        16,
        0,0,0,0,0,0,0
    };
    int indexPixelFormat = ChoosePixelFormat(hdc, &pfd);
    SetPixelFormat(hdc, indexPixelFormat, &pfd);
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    switch(msg)
    {
        case WM_CREATE:
            if ((hdc = GetDC(hwnd)) == NULL)	// get device context
            {
                MessageBox(hwnd, "Failed to Get the Window Device Context", "Device Context Error", MB_OK);
                SysShutdown();
                break;
            }
            setPixelFormat();
            if ((hglrc = wglCreateContext(hdc)) == NULL)
            {
                MessageBox(hwnd, "Failed to Create the OpenGL Rendering Context", "OpenGL Rendering Context Error", MB_OK);
                SysShutdown();
                break;
            }
            if (!wglMakeCurrent(hdc, hglrc))
            {
                MessageBox(hwnd, "Failed to make OpenGL Rendering Context current", "OpenGL Rendering Context Error", MB_OK);
                SysShutdown();
                break;
            }
            glDisable(GL_DEPTH_TEST);
            glDisable(GL_CULL_FACE);
            if (!exampleInit())
            {
                SysShutdown();
                break;
            }
            break;
        
        case WM_SIZE:
            screenw = LOWORD(lParam);
            screenh = HIWORD(lParam);
            break;
        
        case WM_PAINT:
            glClearColor(1.0, 1.0, 1.0, 1.0);
            glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
            glViewport(0, 0, screenw, screenh);
            
            glMatrixMode(GL_PROJECTION);
            glLoadIdentity();
            glOrtho(0, screenw, screenh, 0, -10, 10);
            glMatrixMode(GL_MODELVIEW);
            glLoadIdentity();
            
            if (!exampleRender(screenw, screenh))
                SysShutdown();
            
            SwapBuffers(hdc);
            break;
        
        case WM_CLOSE:
            SysShutdown();
            DestroyWindow(hwnd);
            break;
            
        case WM_DESTROY:
            SysShutdown();
            PostQuitMessage(0);
            break;
            
        default:
            return DefWindowProc(hwnd, msg, wParam, lParam);
    }
    return 0;
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    WNDCLASSEX wc;
    MSG Msg;

    wc.cbSize        = sizeof(WNDCLASSEX);
    wc.style         = 0;
    wc.lpfnWndProc   = WndProc;
    wc.cbClsExtra    = 0;
    wc.cbWndExtra    = 0;
    wc.hInstance     = hInstance;
    wc.hIcon         = LoadIcon(NULL, IDI_APPLICATION);
    wc.hCursor       = LoadCursor(NULL, IDC_ARROW);
    wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
    wc.lpszMenuName  = NULL;
    wc.lpszClassName = g_szClassName;
    wc.hIconSm       = LoadIcon(NULL, IDI_APPLICATION);

    if(!RegisterClassEx(&wc))
    {
        MessageBox(NULL, "Window Registration Failed!", "Error!",
            MB_ICONEXCLAMATION | MB_OK);
        return 0;
    }

    if ((hwnd = CreateWindowEx(
        WS_EX_CLIENTEDGE,
        g_szClassName,
        "libTextSuite example",
        WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT, 640, 480,
        NULL, NULL, hInstance, NULL)) == NULL)
    {
        MessageBox(NULL, "Window Creation Failed!", "Error!", MB_ICONEXCLAMATION | MB_OK);
        return 0;
    }
    
    ShowWindow(hwnd, nCmdShow);
    UpdateWindow(hwnd);
        
    while(GetMessage(&Msg, NULL, 0, 0) > 0 && done == 0)
    {
        TranslateMessage(&Msg);
        DispatchMessage(&Msg);
    }
    return Msg.wParam;
}