/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2012 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/
#include "SDL_config.h"

#ifdef SDL_JOYSTICK_IOKIT

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

#include <unistd.h>
#include <ctype.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 Mac OS 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 */

/* For force feedback testing. */
#include <ForceFeedback/ForceFeedback.h>
#include <ForceFeedback/ForceFeedbackConstants.h>

#include "SDL_joystick.h"
#include "../SDL_sysjoystick.h"
#include "../SDL_joystick_c.h"
#include "SDL_sysjoystick_c.h"


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


static 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
 */

static 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)
                pElement->minReport = hidEvent.value;
            if (hidEvent.value > pElement->maxReport)
                pElement->maxReport = hidEvent.value;
        }
    }

    /* auto user scale */
    return hidEvent.value;
}

static 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;
}


static void
HIDRemovalCallback(void *target, IOReturn result, void *refcon, void *sender)
{
    recDevice *device = (recDevice *) refcon;
    device->removed = 1;
    device->uncentered = 1;
}



/* 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
 */

static 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);
        else
            (*(pDevice->interface))->setRemovalCallback(pDevice->interface,
                                                        HIDRemovalCallback,
                                                        pDevice, pDevice);

    }
    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)
 */

static 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->minReport = pElement->min = number;
    pElement->maxReport = pElement->min;
    refType = CFDictionaryGetValue(refElement, CFSTR(kIOHIDElementMaxKey));
    if (refType && CFNumberGetValue(refType, kCFNumberLongType, &number))
        pElement->maxReport = pElement->max = number;
/*
	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:
                        case kHIDUsage_GD_Slider:
                        case kHIDUsage_GD_Dial:
                        case kHIDUsage_GD_Wheel:
                            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 */
        recElement *elementPrevious = NULL;
        recElement *elementCurrent = *headElement;
        while (elementCurrent && usage >= elementCurrent->usage) {
            elementPrevious = elementCurrent;
            elementCurrent = elementCurrent->pNext;
        }
        if (elementPrevious) {
            elementPrevious->pNext = element;
        } else {
            *headElement = element;
        }
        element->usagePage = usagePage;
        element->usage = usage;
        element->pNext = elementCurrent;
        HIDGetElementInfo(refElement, element);
        pDevice->elements++;
    }
}

/* 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 posible io_service_t */
        if ((*ppDevice)->ffservice) {
            IOObjectRelease((*ppDevice)->ffservice);
            (*ppDevice)->ffservice = 0;
        }

        /* 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 = 0;
    io_iterator_t hidObjectIterator = 0;
    CFMutableDictionaryRef hidMatchDictionary = NULL;
    recDevice *device, *lastDevice;
    io_object_t ioHIDDeviceObject = 0;

    SDL_numjoysticks = 0;

    if (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) {
        /* 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 (!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;

        /* Filter device list to non-keyboard/mouse stuff */
        if ((device->usagePage != kHIDPage_GenericDesktop) ||
            ((device->usage != kHIDUsage_GD_Joystick &&
              device->usage != kHIDUsage_GD_GamePad &&
              device->usage != kHIDUsage_GD_MultiAxisController))) {

            /* release memory for the device */
            HIDDisposeDevice(&device);
            DisposePtr((Ptr) device);
            continue;
        }

        /* We have to do some storage of the io_service_t for
         * SDL_HapticOpenFromJoystick */
        if (FFIsForceFeedback(ioHIDDeviceObject) == FF_OK) {
            device->ffservice = ioHIDDeviceObject;
        } else {
            device->ffservice = 0;
        }

        /* 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, range;
    int i;

    if (device->removed) {      /* device was unplugged; ignore it. */
        if (device->uncentered) {
            device->uncentered = 0;

            /* Tell the app that everything is centered/unpressed... */
            for (i = 0; i < device->axes; i++)
                SDL_PrivateJoystickAxis(joystick, i, 0);

            for (i = 0; i < device->buttons; i++)
                SDL_PrivateJoystickButton(joystick, i, 0);

            for (i = 0; i < device->hats; i++)
                SDL_PrivateJoystickHat(joystick, i, SDL_HAT_CENTERED);
        }

        return;
    }

    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 > 1)          /* handle pressure-sensitive buttons */
            value = 1;
        if (value != joystick->buttons[i])
            SDL_PrivateJoystickButton(joystick, i, value);
        element = element->pNext;
        ++i;
    }

    element = device->firstHat;
    i = 0;
    while (element) {
        Uint8 pos = 0;

        range = (element->max - element->min + 1);
        value = HIDGetElementValue(device, element) - element->min;
        if (range == 4)         /* 4 position hatswitch - scale up value */
            value *= 2;
        else if (range != 8)    /* Neither a 4 nor 8 positions - fall back to default position (centered) */
            value = -1;
        switch (value) {
        case 0:
            pos = SDL_HAT_UP;
            break;
        case 1:
            pos = SDL_HAT_RIGHTUP;
            break;
        case 2:
            pos = SDL_HAT_RIGHT;
            break;
        case 3:
            pos = SDL_HAT_RIGHTDOWN;
            break;
        case 4:
            pos = SDL_HAT_DOWN;
            break;
        case 5:
            pos = SDL_HAT_LEFTDOWN;
            break;
        case 6:
            pos = SDL_HAT_LEFT;
            break;
        case 7:
            pos = SDL_HAT_LEFTUP;
            break;
        default:
            /* Every other value is mapped to center. We do that because some
             * joysticks use 8 and some 15 for this value, and apparently
             * there are even more variants out there - so we try to be generous.
             */
            pos = SDL_HAT_CENTERED;
            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);
}

#endif /* SDL_JOYSTICK_IOKIT */
/* vi: set ts=4 sw=4 expandtab: */
