/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002  Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public
    License along with this library; if not, write to the Free
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    Sam Lantinga
    slouken@libsdl.org
*/

/* SDL joystick driver for Darwin / MacOS X, based on the IOKit HID API */
/* Written 2001 by Max Horn */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <ctype.h>
#include <sys/errno.h>
#include <sysexits.h>
#include <mach/mach.h>
#include <mach/mach_error.h>
#include <IOKit/IOKitLib.h>
#include <IOKit/IOCFPlugIn.h>
#ifdef MACOS_10_0_4
#include <IOKit/hidsystem/IOHIDUsageTables.h>
#else
/* The header was moved here in MacOS X 10.1 */
#include <Kernel/IOKit/hidsystem/IOHIDUsageTables.h>
#endif
#include <IOKit/hid/IOHIDLib.h>
#include <IOKit/hid/IOHIDKeys.h>
#include <CoreFoundation/CoreFoundation.h>
#include <Carbon/Carbon.h> /* for NewPtrClear, DisposePtr */

#include "SDL_error.h"
#include "SDL_joystick.h"
#include "SDL_sysjoystick.h"
#include "SDL_joystick_c.h"

struct recElement
{
    IOHIDElementCookie cookie; // unique value which identifies element, will 
                               // NOT change
    long min;                  // reported min value possible
    long max;                  // reported max value possible
/*
    TODO: maybe should handle the following stuff somehow?

    long scaledMin;            // reported scaled min value possible
    long scaledMax;            // reported scaled max value possible
    long size;                 // size in bits of data return from element
    Boolean relative;          // are reports relative to last report (deltas)
    Boolean wrapping;          // does element wrap around (one value higher 
                               //                           than max is min)
    Boolean nonLinear;         // are the values reported non-linear relative 
                               // to element movement
    Boolean preferredState;    // does element have a preferred state 
                               // (such as a button)
    Boolean nullState;         // does element have null state
*/

    /* runtime variables used for auto-calibration */
    long minReport;            // min returned value
    long maxReport;            // max returned value
    
    struct recElement * pNext; // next element in list
};
typedef struct recElement recElement;

struct joystick_hwdata
{
    IOHIDDeviceInterface ** interface;  // interface to device, 
                                        // NULL = no interface

    char product[256];                  // name of product
    long usage;                         // usage page from IOUSBHID Parser.h 
                                        // which defines general usage
    long usagePage;                     // usage within above page from IOUSBHID Parser.h which defines specific usage

    long axes;                          // number of axis (calculated, not reported by device)
    long buttons;                       // number of buttons (calculated, not reported by device)
    long hats;                          // number of hat switches (calculated, not reported by device)
    long elements;                      // number of total elements (shouldbe total of above) (calculated, not reported by device)

    recElement* firstAxis;
    recElement* firstButton;
    recElement* firstHat;

    struct joystick_hwdata* pNext;            // next device
};
typedef struct joystick_hwdata recDevice;


/* Linked list of all available devices */
static recDevice *gpDeviceList = NULL;


void HIDReportErrorNum (char * strError, long numError)
{
    SDL_SetError(strError);
}

static void HIDGetCollectionElements (CFMutableDictionaryRef deviceProperties, recDevice *pDevice);

/* returns current value for element, polling element
 * will return 0 on error conditions which should be accounted for by application
 */

SInt32 HIDGetElementValue (recDevice *pDevice, recElement *pElement)
{
    IOReturn result = kIOReturnSuccess;
    IOHIDEventStruct hidEvent;
    hidEvent.value = 0;
    
    if (NULL != pDevice && NULL != pElement && NULL != pDevice->interface)
    {
        result = (*(pDevice->interface))->getElementValue(pDevice->interface, pElement->cookie, &hidEvent);
        if (kIOReturnSuccess == result)
        {
            /* record min and max for auto calibration */
            if (hidEvent.value < pElement->minReport) {
#ifdef DEBUG
                                fprintf(stderr,"minReport old value %ld\n",pElement->minReport);
#endif
                pElement->minReport = hidEvent.value;
#ifdef DEBUG
                                fprintf(stderr,"minReport new value %ld\n",pElement->minReport);
#endif
                        }
            if (hidEvent.value > pElement->maxReport) {
#ifdef DEBUG
                                fprintf(stderr,"maxReport old value %ld\n",pElement->maxReport);
#endif
                pElement->maxReport = hidEvent.value;
#ifdef DEBUG
                                fprintf(stderr,"maxReport new value %ld\n",pElement->maxReport);
#endif
                        }

        }
    }

    // auto user scale
    return hidEvent.value;
}

/* similiar to HIDGetElementValue, but auto-calibrates the value before returning it */

SInt32 HIDCalibratedValue (recDevice *pDevice, recElement *pElement)
{
    float deviceScale = pElement->max - pElement->min;
    float readScale = pElement->maxReport - pElement->minReport;
    SInt32 value = HIDGetElementValue(pDevice, pElement);
    if (readScale == 0)
        return value; // no scaling at all
    else
        return ((value - pElement->minReport) * deviceScale / readScale) + pElement->min;
}

/* similiar to HIDCalibratedValue but calibrates to an arbitrary scale instead of the elements default scale */

SInt32 HIDScaledCalibratedValue (recDevice *pDevice, recElement *pElement, long min, long max)
{
    float deviceScale = max - min;
    float readScale = pElement->maxReport - pElement->minReport;
    SInt32 value = HIDGetElementValue(pDevice, pElement);
    if (readScale == 0)
        return value; // no scaling at all
    else
        return ((value - pElement->minReport) * deviceScale / readScale) + min;
}

/* Create and open an interface to device, required prior to extracting values or building queues.
 * Note: appliction now owns the device and must close and release it prior to exiting
 */

IOReturn HIDCreateOpenDeviceInterface (io_object_t hidDevice, recDevice *pDevice)
{
    IOReturn result = kIOReturnSuccess;
    HRESULT plugInResult = S_OK;
    SInt32 score = 0;
    IOCFPlugInInterface ** ppPlugInInterface = NULL;
    
    if (NULL == pDevice->interface)
    {
        result = IOCreatePlugInInterfaceForService (hidDevice, kIOHIDDeviceUserClientTypeID,
                                                    kIOCFPlugInInterfaceID, &ppPlugInInterface, &score);
        if (kIOReturnSuccess == result)
        {
            // Call a method of the intermediate plug-in to create the device interface
            plugInResult = (*ppPlugInInterface)->QueryInterface (ppPlugInInterface,
                                CFUUIDGetUUIDBytes (kIOHIDDeviceInterfaceID), (void *) &(pDevice->interface));
            if (S_OK != plugInResult)
                HIDReportErrorNum ("CouldnŐt query HID class device interface from plugInInterface", plugInResult);
            (*ppPlugInInterface)->Release (ppPlugInInterface);
        }
        else
            HIDReportErrorNum ("Failed to create **plugInInterface via IOCreatePlugInInterfaceForService.", result);
    }
    if (NULL != pDevice->interface)
    {
        result = (*(pDevice->interface))->open (pDevice->interface, 0);
        if (kIOReturnSuccess != result)
            HIDReportErrorNum ("Failed to open pDevice->interface via open.", result);
    }
    return result;
}

/* Closes and releases interface to device, should be done prior to exting application
 * Note: will have no affect if device or interface do not exist
 * application will "own" the device if interface is not closed
 * (device may have to be plug and re-plugged in different location to get it working again without a restart)
 */

IOReturn HIDCloseReleaseInterface (recDevice *pDevice)
{
    IOReturn result = kIOReturnSuccess;
    
    if ((NULL != pDevice) && (NULL != pDevice->interface))
    {
        // close the interface
        result = (*(pDevice->interface))->close (pDevice->interface);
        if (kIOReturnNotOpen == result)
        {
            //  do nothing as device was not opened, thus can't be closed
        }
        else if (kIOReturnSuccess != result)
            HIDReportErrorNum ("Failed to close IOHIDDeviceInterface.", result);
        //release the interface
        result = (*(pDevice->interface))->Release (pDevice->interface);
        if (kIOReturnSuccess != result)
            HIDReportErrorNum ("Failed to release IOHIDDeviceInterface.", result);
        pDevice->interface = NULL;
    }    
    return result;
}

/* extracts actual specific element information from each element CF dictionary entry */

static void HIDGetElementInfo (CFTypeRef refElement, recElement *pElement)
{
    long number;
    CFTypeRef refType;

    refType = CFDictionaryGetValue (refElement, CFSTR(kIOHIDElementCookieKey));
    if (refType && CFNumberGetValue (refType, kCFNumberLongType, &number))
        pElement->cookie = (IOHIDElementCookie) number;
    refType = CFDictionaryGetValue (refElement, CFSTR(kIOHIDElementMinKey));
    if (refType && CFNumberGetValue (refType, kCFNumberLongType, &number)) {
        pElement->min = number;
        pElement->minReport = pElement->min;
        }
    refType = CFDictionaryGetValue (refElement, CFSTR(kIOHIDElementMaxKey));
    if (refType && CFNumberGetValue (refType, kCFNumberLongType, &number)) {
        pElement->max = number;
        pElement->maxReport = pElement->max;
        }
/*
    TODO: maybe should handle the following stuff somehow?

    refType = CFDictionaryGetValue (refElement, CFSTR(kIOHIDElementScaledMinKey));
    if (refType && CFNumberGetValue (refType, kCFNumberLongType, &number))
        pElement->scaledMin = number;
    refType = CFDictionaryGetValue (refElement, CFSTR(kIOHIDElementScaledMaxKey));
    if (refType && CFNumberGetValue (refType, kCFNumberLongType, &number))
        pElement->scaledMax = number;
    refType = CFDictionaryGetValue (refElement, CFSTR(kIOHIDElementSizeKey));
    if (refType && CFNumberGetValue (refType, kCFNumberLongType, &number))
        pElement->size = number;
    refType = CFDictionaryGetValue (refElement, CFSTR(kIOHIDElementIsRelativeKey));
    if (refType)
        pElement->relative = CFBooleanGetValue (refType);
    refType = CFDictionaryGetValue (refElement, CFSTR(kIOHIDElementIsWrappingKey));
    if (refType)
        pElement->wrapping = CFBooleanGetValue (refType);
    refType = CFDictionaryGetValue (refElement, CFSTR(kIOHIDElementIsNonLinearKey));
    if (refType)
        pElement->nonLinear = CFBooleanGetValue (refType);
    refType = CFDictionaryGetValue (refElement, CFSTR(kIOHIDElementHasPreferedStateKey));
    if (refType)
        pElement->preferredState = CFBooleanGetValue (refType);
    refType = CFDictionaryGetValue (refElement, CFSTR(kIOHIDElementHasNullStateKey));
    if (refType)
        pElement->nullState = CFBooleanGetValue (refType);
*/
}            

/* examines CF dictionary vlaue in device element hierarchy to determine if it is element of interest or a collection of more elements
 * if element of interest allocate storage, add to list and retrieve element specific info
 * if collection then pass on to deconstruction collection into additional individual elements
 */

static void HIDAddElement (CFTypeRef refElement, recDevice* pDevice)
{
    recElement* element = NULL;
    recElement** headElement = NULL;
    long elementType, usagePage, usage;
    CFTypeRef refElementType = CFDictionaryGetValue (refElement, CFSTR(kIOHIDElementTypeKey));
    CFTypeRef refUsagePage = CFDictionaryGetValue (refElement, CFSTR(kIOHIDElementUsagePageKey));
    CFTypeRef refUsage = CFDictionaryGetValue (refElement, CFSTR(kIOHIDElementUsageKey));


    if ((refElementType) && (CFNumberGetValue (refElementType, kCFNumberLongType, &elementType)))
    {
        /* look at types of interest */
        if ((elementType == kIOHIDElementTypeInput_Misc) || (elementType == kIOHIDElementTypeInput_Button) ||
            (elementType == kIOHIDElementTypeInput_Axis))
        {
            if (refUsagePage && CFNumberGetValue (refUsagePage, kCFNumberLongType, &usagePage) &&
                refUsage && CFNumberGetValue (refUsage, kCFNumberLongType, &usage))
            {
                switch (usagePage) /* only interested in kHIDPage_GenericDesktop and kHIDPage_Button */
                {
                    case kHIDPage_GenericDesktop:
                        {
                            switch (usage) /* look at usage to determine function */
                            {
                                case kHIDUsage_GD_X:
                                case kHIDUsage_GD_Y:
                                case kHIDUsage_GD_Z:
                                case kHIDUsage_GD_Rx:
                                case kHIDUsage_GD_Ry:
                                case kHIDUsage_GD_Rz:
                                    element = (recElement *) NewPtrClear (sizeof (recElement));
                                    if (element)
                                    {
                                        pDevice->axes++;
                                        headElement = &(pDevice->firstAxis);
                                    }
                                break;
                                case kHIDUsage_GD_Hatswitch:
                                    element = (recElement *) NewPtrClear (sizeof (recElement));
                                    if (element)
                                    {
                                        pDevice->hats++;
                                        headElement = &(pDevice->firstHat);
                                    }
                                break;
                            }                            
                        }
                        break;
                    case kHIDPage_Button:
                        element = (recElement *) NewPtrClear (sizeof (recElement));
                        if (element)
                        {
                            pDevice->buttons++;
                            headElement = &(pDevice->firstButton);
                        }
                        break;
                    default:
                        break;
                }
            }
        }
        else if (kIOHIDElementTypeCollection == elementType)
            HIDGetCollectionElements ((CFMutableDictionaryRef) refElement, pDevice);
    }

    if (element && headElement) /* add to list */
    {
        pDevice->elements++;
        if (NULL == *headElement)
            *headElement = element;
        else
        {
            recElement *elementPrevious, *elementCurrent;
            elementCurrent = *headElement;
            while (elementCurrent)
            {
                elementPrevious = elementCurrent;
                elementCurrent = elementPrevious->pNext;
            }
            elementPrevious->pNext = element;
        }
        element->pNext = NULL;
        HIDGetElementInfo (refElement, element);
    }
}

/* collects information from each array member in device element list (each array memeber = element) */

static void HIDGetElementsCFArrayHandler (const void * value, void * parameter)
{
    if (CFGetTypeID (value) == CFDictionaryGetTypeID ())
        HIDAddElement ((CFTypeRef) value, (recDevice *) parameter);
}

/* handles retrieval of element information from arrays of elements in device IO registry information */

static void HIDGetElements (CFTypeRef refElementCurrent, recDevice *pDevice)
{
    CFTypeID type = CFGetTypeID (refElementCurrent);
    if (type == CFArrayGetTypeID()) /* if element is an array */
    {
        CFRange range = {0, CFArrayGetCount (refElementCurrent)};
        /* CountElementsCFArrayHandler called for each array member */
        CFArrayApplyFunction (refElementCurrent, range, HIDGetElementsCFArrayHandler, pDevice);
    }
}            

/* handles extracting element information from element collection CF types
 * used from top level element decoding and hierarchy deconstruction to flatten device element list
 */

static void HIDGetCollectionElements (CFMutableDictionaryRef deviceProperties, recDevice *pDevice)
{
    CFTypeRef refElementTop = CFDictionaryGetValue (deviceProperties, CFSTR(kIOHIDElementKey));
    if (refElementTop)
        HIDGetElements (refElementTop, pDevice);
}

/* use top level element usage page and usage to discern device usage page and usage setting appropriate vlaues in device record */

static void HIDTopLevelElementHandler (const void * value, void * parameter)
{
    CFTypeRef refCF = 0;
    if (CFGetTypeID (value) != CFDictionaryGetTypeID ())
        return;
    refCF = CFDictionaryGetValue (value, CFSTR(kIOHIDElementUsagePageKey));
    if (!CFNumberGetValue (refCF, kCFNumberLongType, &((recDevice *) parameter)->usagePage))
        SDL_SetError ("CFNumberGetValue error retrieving pDevice->usagePage.");
    refCF = CFDictionaryGetValue (value, CFSTR(kIOHIDElementUsageKey));
    if (!CFNumberGetValue (refCF, kCFNumberLongType, &((recDevice *) parameter)->usage))
        SDL_SetError ("CFNumberGetValue error retrieving pDevice->usage.");
}

/* extracts device info from CF dictionary records in IO registry */

static void HIDGetDeviceInfo (io_object_t hidDevice, CFMutableDictionaryRef hidProperties, recDevice *pDevice)
{
    CFMutableDictionaryRef usbProperties = 0;
    io_registry_entry_t parent1, parent2;
    
    /* Mac OS X currently is not mirroring all USB properties to HID page so need to look at USB device page also
     * get dictionary for usb properties: step up two levels and get CF dictionary for USB properties
     */
    if ((KERN_SUCCESS == IORegistryEntryGetParentEntry (hidDevice, kIOServicePlane, &parent1)) &&
        (KERN_SUCCESS == IORegistryEntryGetParentEntry (parent1, kIOServicePlane, &parent2)) &&
        (KERN_SUCCESS == IORegistryEntryCreateCFProperties (parent2, &usbProperties, kCFAllocatorDefault, kNilOptions)))
    {
        if (usbProperties)
        {
            CFTypeRef refCF = 0;
            /* get device info
             * try hid dictionary first, if fail then go to usb dictionary
             */
            
            
            /* get product name */
            refCF = CFDictionaryGetValue (hidProperties, CFSTR(kIOHIDProductKey));
            if (!refCF)
                refCF = CFDictionaryGetValue (usbProperties, CFSTR("USB Product Name"));
            if (refCF)
            {
                if (!CFStringGetCString (refCF, pDevice->product, 256, CFStringGetSystemEncoding ()))
                    SDL_SetError ("CFStringGetCString error retrieving pDevice->product.");
            }
            
            /* get usage page and usage */
            refCF = CFDictionaryGetValue (hidProperties, CFSTR(kIOHIDPrimaryUsagePageKey));
            if (refCF)
            {
                if (!CFNumberGetValue (refCF, kCFNumberLongType, &pDevice->usagePage))
                    SDL_SetError ("CFNumberGetValue error retrieving pDevice->usagePage.");
                refCF = CFDictionaryGetValue (hidProperties, CFSTR(kIOHIDPrimaryUsageKey));
                if (refCF)
                    if (!CFNumberGetValue (refCF, kCFNumberLongType, &pDevice->usage))
                        SDL_SetError ("CFNumberGetValue error retrieving pDevice->usage.");
            }

            if (NULL == refCF) /* get top level element HID usage page or usage */
            {
                /* use top level element instead */
                CFTypeRef refCFTopElement = 0;
                refCFTopElement = CFDictionaryGetValue (hidProperties, CFSTR(kIOHIDElementKey));
                {
                    /* refCFTopElement points to an array of element dictionaries */
                    CFRange range = {0, CFArrayGetCount (refCFTopElement)};
                    CFArrayApplyFunction (refCFTopElement, range, HIDTopLevelElementHandler, pDevice);
                }
            }

            CFRelease (usbProperties);
        }
        else
            SDL_SetError ("IORegistryEntryCreateCFProperties failed to create usbProperties.");

        if (kIOReturnSuccess != IOObjectRelease (parent2))
            SDL_SetError ("IOObjectRelease error with parent2.");
        if (kIOReturnSuccess != IOObjectRelease (parent1))
            SDL_SetError ("IOObjectRelease error with parent1.");
    }
}


static recDevice *HIDBuildDevice (io_object_t hidDevice)
{
    recDevice *pDevice = (recDevice *) NewPtrClear (sizeof (recDevice));
    if (pDevice)
    {
        /* get dictionary for HID properties */
        CFMutableDictionaryRef hidProperties = 0;
        kern_return_t result = IORegistryEntryCreateCFProperties (hidDevice, &hidProperties, kCFAllocatorDefault, kNilOptions);
        if ((result == KERN_SUCCESS) && hidProperties)
        {
            /* create device interface */
            result = HIDCreateOpenDeviceInterface (hidDevice, pDevice);
            if (kIOReturnSuccess == result)
            {
                HIDGetDeviceInfo (hidDevice, hidProperties, pDevice); /* hidDevice used to find parents in registry tree */
                HIDGetCollectionElements (hidProperties, pDevice);
            }
            else
            {
                DisposePtr((Ptr)pDevice);
                pDevice = NULL;
            }
            CFRelease (hidProperties);
        }
        else
        {
            DisposePtr((Ptr)pDevice);
            pDevice = NULL;
        }
    }
    return pDevice;
}

/* disposes of the element list associated with a device and the memory associated with the list
 */

static void HIDDisposeElementList (recElement **elementList)
{
    recElement *pElement = *elementList;
    while (pElement)
    {
        recElement *pElementNext = pElement->pNext;
        DisposePtr ((Ptr) pElement);
        pElement = pElementNext;
    }
    *elementList = NULL;
}

/* disposes of a single device, closing and releaseing interface, freeing memory fro device and elements, setting device pointer to NULL
 * all your device no longer belong to us... (i.e., you do not 'own' the device anymore)
 */

static recDevice *HIDDisposeDevice (recDevice **ppDevice)
{
    kern_return_t result = KERN_SUCCESS;
    recDevice *pDeviceNext = NULL;
    if (*ppDevice)
    {
        // save next device prior to disposing of this device
        pDeviceNext = (*ppDevice)->pNext;
        
        /* free element lists */
        HIDDisposeElementList (&(*ppDevice)->firstAxis);
        HIDDisposeElementList (&(*ppDevice)->firstButton);
        HIDDisposeElementList (&(*ppDevice)->firstHat);
        
        result = HIDCloseReleaseInterface (*ppDevice); /* function sanity checks interface value (now application does not own device) */
        if (kIOReturnSuccess != result)
            HIDReportErrorNum ("HIDCloseReleaseInterface failed when trying to dipose device.", result);
        DisposePtr ((Ptr)*ppDevice);
        *ppDevice = NULL;
    }
    return pDeviceNext;
}


/* Function to scan the system for joysticks.
 * Joystick 0 should be the system default joystick.
 * This function should return the number of available joysticks, or -1
 * on an unrecoverable fatal error.
 */
int SDL_SYS_JoystickInit(void)
{
    IOReturn result = kIOReturnSuccess;
    mach_port_t masterPort = NULL;
    io_iterator_t hidObjectIterator = NULL;
    CFMutableDictionaryRef hidMatchDictionary = NULL;
    recDevice *device, *lastDevice;
    io_object_t ioHIDDeviceObject = NULL;
    
    SDL_numjoysticks = 0;
    
    if (NULL != gpDeviceList)
    {
        SDL_SetError("Joystick: Device list already inited.");
        return -1;
    }
    
    result = IOMasterPort (bootstrap_port, &masterPort);
    if (kIOReturnSuccess != result)
    {
        SDL_SetError("Joystick: IOMasterPort error with bootstrap_port.");
        return -1;
    }

    /* Set up a matching dictionary to search I/O Registry by class name for all HID class devices. */
    hidMatchDictionary = IOServiceMatching (kIOHIDDeviceKey);
    if ((hidMatchDictionary != NULL))
    {
        /* Add key for device type (joystick, in this case) to refine the matching dictionary. */
        
        /* NOTE: we now perform this filtering later
        UInt32 usagePage = kHIDPage_GenericDesktop;
        UInt32 usage = kHIDUsage_GD_Joystick;
        CFNumberRef refUsage = NULL, refUsagePage = NULL;

        refUsage = CFNumberCreate (kCFAllocatorDefault, kCFNumberIntType, &usage);
        CFDictionarySetValue (hidMatchDictionary, CFSTR (kIOHIDPrimaryUsageKey), refUsage);
        refUsagePage = CFNumberCreate (kCFAllocatorDefault, kCFNumberIntType, &usagePage);
        CFDictionarySetValue (hidMatchDictionary, CFSTR (kIOHIDPrimaryUsagePageKey), refUsagePage);
        */
    }
    else
    {
        SDL_SetError("Joystick: Failed to get HID CFMutableDictionaryRef via IOServiceMatching.");
        return -1;
    }
    
    /*/ Now search I/O Registry for matching devices. */
    result = IOServiceGetMatchingServices (masterPort, hidMatchDictionary, &hidObjectIterator);
    /* Check for errors */
    if (kIOReturnSuccess != result)
    {
        SDL_SetError("Joystick: Couldn't create a HID object iterator.");
        return -1;
    }
    if (NULL == hidObjectIterator) /* there are no joysticks */
    {
        gpDeviceList = NULL;
        SDL_numjoysticks = 0;
        return 0;
    }
    /* IOServiceGetMatchingServices consumes a reference to the dictionary, so we don't need to release the dictionary ref. */

    /* build flat linked list of devices from device iterator */

    gpDeviceList = lastDevice = NULL;
    
    while ((ioHIDDeviceObject = IOIteratorNext (hidObjectIterator)))
    {
        /* build a device record */
        device = HIDBuildDevice (ioHIDDeviceObject);
        if (!device)
            continue;

        /* dump device object, it is no longer needed */
        result = IOObjectRelease (ioHIDDeviceObject);
//        if (KERN_SUCCESS != result)
//            HIDReportErrorNum ("IOObjectRelease error with ioHIDDeviceObject.", result);

        /* Filter device list to non-keyboard/mouse stuff */ 
        if ( device->usagePage == kHIDPage_GenericDesktop &&
             (device->usage == kHIDUsage_GD_Keyboard ||
              device->usage == kHIDUsage_GD_Mouse)) {
            
            /* release memory for the device */
            HIDDisposeDevice (&device);
            DisposePtr((Ptr)device);
            continue;
        }
        
        /* Add device to the end of the list */
        if (lastDevice)
            lastDevice->pNext = device;
        else
            gpDeviceList = device;
        lastDevice = device;
    }
    result = IOObjectRelease (hidObjectIterator); /* release the iterator */

    /* Count the total number of devices we found */
    device = gpDeviceList;
    while (device)
    {
        SDL_numjoysticks++;
        device = device->pNext;
    }
    
    return SDL_numjoysticks;
}

/* Function to get the device-dependent name of a joystick */
const char *SDL_SYS_JoystickName(int index)
{
    recDevice *device = gpDeviceList;
    
    for (; index > 0; index--)
        device = device->pNext;

    return device->product;
}

/* Function to open a joystick for use.
 * The joystick to open is specified by the index field of the joystick.
 * This should fill the nbuttons and naxes fields of the joystick structure.
 * It returns 0, or -1 if there is an error.
 */
int SDL_SYS_JoystickOpen(SDL_Joystick *joystick)
{
    recDevice *device = gpDeviceList;
    int index;
    
    for (index = joystick->index; index > 0; index--)
        device = device->pNext;

    joystick->hwdata = device;
    joystick->name = device->product;

    joystick->naxes = device->axes;
    joystick->nhats = device->hats;
    joystick->nballs = 0;
    joystick->nbuttons = device->buttons;

    return 0;
}

/* Function to update the state of a joystick - called as a device poll.
 * This function shouldn't update the joystick structure directly,
 * but instead should call SDL_PrivateJoystick*() to deliver events
 * and update joystick device state.
 */
void SDL_SYS_JoystickUpdate(SDL_Joystick *joystick)
{
    recDevice *device = joystick->hwdata;
    recElement *element;
    SInt32 value;
    int i;
    
    element = device->firstAxis;
    i = 0;
    while (element)
    {
        value = HIDScaledCalibratedValue(device, element, -32768, 32767);
        if ( value != joystick->axes[i] )
            SDL_PrivateJoystickAxis(joystick, i, value);
        element = element->pNext;
        ++i;
    }
    
    element = device->firstButton;
    i = 0;
    while (element)
    {
        value = HIDGetElementValue(device, element);
        if ( value != joystick->buttons[i] )
            SDL_PrivateJoystickButton(joystick, i, value);
        element = element->pNext;
        ++i;
    }
    
    element = device->firstHat;
    i = 0;
    while (element)
    {
        Uint8 pos = 0;

        value = HIDGetElementValue(device, element);
        switch(value)
        {
            case 0:
                pos = SDL_HAT_CENTERED;
                break;
            case 1:
                pos = SDL_HAT_UP;
                break;
            case 2:
                pos = SDL_HAT_RIGHTUP;
                break;
            case 3:
                pos = SDL_HAT_RIGHT;
                break;
            case 4:
                pos = SDL_HAT_RIGHTDOWN;
                break;
            case 5:
                pos = SDL_HAT_DOWN;
                break;
            case 6:
                pos = SDL_HAT_LEFTDOWN;
                break;
            case 7:
                pos = SDL_HAT_LEFT;
                break;
            case 8:
                pos = SDL_HAT_LEFTUP;
                break;
        }
        if ( pos != joystick->hats[i] )
            SDL_PrivateJoystickHat(joystick, i, pos);
        element = element->pNext;
        ++i;
    }
    
    return;
}

/* Function to close a joystick after use */
void SDL_SYS_JoystickClose(SDL_Joystick *joystick)
{
    /* Should we do anything here? */
    return;
}

/* Function to perform any system-specific joystick related cleanup */
void SDL_SYS_JoystickQuit(void)
{
    while (NULL != gpDeviceList)
        gpDeviceList = HIDDisposeDevice (&gpDeviceList);
}
