// Simple Apple OpenGL framework

#ifdef __APPLE__

#include <Carbon/Carbon.h>
#include <AGL/agl.h>
#include <OpenGL/gl.h>
#include <OpenGL/glu.h>
#include <OpenGL/glext.h>

static AGLContext setupAGL(WindowRef window)
{
    if ((Ptr) kUnresolvedCFragSymbolAddress == (Ptr) aglChoosePixelFormat)
        return 0;

    GLint attributes[] = { AGL_RGBA, AGL_DOUBLEBUFFER, AGL_DEPTH_SIZE, 16, AGL_NONE };

    AGLPixelFormat format = aglChoosePixelFormat(NULL, 0, attributes);
    if (!format)
        return 0;

    AGLContext context = aglCreateContext(format, 0);
    if (!context)
        return 0;

    aglDestroyPixelFormat(format);

    aglSetDrawable(context, GetWindowPort(window));

    aglSetCurrentContext(context);

    return context;
}

static void cleanupAGL(AGLContext context)
{
    glFlush();
    aglSetDrawable(context, 0);
    aglSetCurrentContext(0);
    aglDestroyContext(context);
}

WindowRef window;
AGLContext context;

static pascal OSErr quitEventHandler(const AppleEvent *appleEvt, AppleEvent *reply, SInt32 refcon)
{
    onQuit();
    return false;
}

bool openDisplay(const char title[], int width, int height)
{
    // create window

    Rect rect;
    rect.top = 100;
    rect.left = 100;
    rect.bottom = rect.top + height;
    rect.right = rect.left + width;

    // todo: center window and adjust client area to match width/height

    OSErr result = CreateNewWindow( kDocumentWindowClass,
                                    (kWindowStandardDocumentAttributes |
                                     kWindowStandardHandlerAttribute) &
                                    ~kWindowResizableAttribute,
                                    &rect, &window);

    if (result!=noErr)
        return false;

    // set window title

    SetWindowTitleWithCFString(window, CFStringCreateWithCString(0, title, CFStringGetSystemEncoding()));

    // initialize apple opengl

    context = setupAGL(window);

    if (!context)
        return false;

    // show the window

    ShowWindow(window);

    // install quit event handler

    AEInstallEventHandler(kCoreEventClass, kAEQuitApplication, NewAEEventHandlerUPP(quitEventHandler), 0, false);

    return true;
}

void updateDisplay(void)
{
    // process pending events

    // todo: process all available events instead of one per update!

    EventRecord event;

    if (WaitNextEvent(everyEvent, &event, 1, NULL))
    {
        switch (event.what)
        {
            case mouseDown:
            {
                WindowRef window;

                SInt16 part = FindWindow(event.where, &window);

                if (window)
                    SelectWindow(window);

                switch (part)
                {
                    case inMenuBar:
                        MenuSelect(event.where);
                        break;
                }
            }
            break;

            case keyDown:
            case autoKey:
            {
                SInt8 key = event.message & charCodeMask;

                if (key==27)
                    onQuit();
            }
            break;
        }
    }

    aglSwapBuffers(context);
}

void closeDisplay(void)
{
    cleanupAGL(context);
    context = 0;

    DisposeWindow((WindowPtr) window);
    window = 0;
}

float time()
{
    static UInt64 start = 0;

    if (start==0)
    {
        Microseconds((UnsignedWide*)&start);
        return 0.0f;
    }

    UInt64 counter = 0;
    Microseconds((UnsignedWide*)&counter);
    return (counter - start) / 1000000.0f;
}

#endif