/*

  Simple DirectMedia Layer

  Copyright (C) 1997-2016 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_internal.h"

/* This is the iOS implementation of the SDL joystick API */

#include "SDL_sysjoystick_c.h"

/* needed for SDL_IPHONE_MAX_GFORCE macro */

#include "SDL_config_iphoneos.h"

#include "SDL_joystick.h"

#include "SDL_hints.h"

#include "SDL_stdinc.h"

#include "../SDL_sysjoystick.h"

#include "../SDL_joystick_c.h"

#import <CoreMotion/CoreMotion.h>

#ifdef SDL_JOYSTICK_MFI

#import <GameController/GameController.h>

static id connectObserver = nil;

static id disconnectObserver = nil;

#endif /* SDL_JOYSTICK_MFI */

static const char *accelerometerName = "iOS Accelerometer";

static CMMotionManager *motionManager = nil;

static SDL_JoystickDeviceItem *deviceList = NULL;

static int numjoysticks = 0;

static SDL_JoystickID instancecounter = 0;

static SDL_JoystickDeviceItem *

GetDeviceForIndex(int device_index)

{

    SDL_JoystickDeviceItem *device = deviceList;

    int i = 0;

    while (i < device_index) {

        if (device == NULL) {

            return NULL;

        }

        device = device->next;

        i++;

    }

    return device;

}

static void

SDL_SYS_AddMFIJoystickDevice(SDL_JoystickDeviceItem *device, GCController *controller)

{

#ifdef SDL_JOYSTICK_MFI

    const char *name = NULL;

    /* Explicitly retain the controller because SDL_JoystickDeviceItem is a

     * struct, and ARC doesn't work with structs. */

    device->controller = (__bridge GCController *) CFBridgingRetain(controller);

    if (controller.vendorName) {

        name = controller.vendorName.UTF8String;

    }

    if (!name) {

        name = "MFi Gamepad";

    }

    device->name = SDL_strdup(name);

    device->guid.data[0] = 'M';

    device->guid.data[1] = 'F';

    device->guid.data[2] = 'i';

    device->guid.data[3] = 'G';

    device->guid.data[4] = 'a';

    device->guid.data[5] = 'm';

    device->guid.data[6] = 'e';

    device->guid.data[7] = 'p';

    device->guid.data[8] = 'a';

    device->guid.data[9] = 'd';

    if (controller.extendedGamepad) {

        device->guid.data[10] = 1;

    } else if (controller.gamepad) {

        device->guid.data[10] = 2;

    }

    if (controller.extendedGamepad) {

        device->naxes = 6; /* 2 thumbsticks and 2 triggers */

        device->nhats = 1; /* d-pad */

        device->nbuttons = 7; /* ABXY, shoulder buttons, pause button */

    } else if (controller.gamepad) {

        device->naxes = 0; /* no traditional analog inputs */

        device->nhats = 1; /* d-pad */

        device->nbuttons = 7; /* ABXY, shoulder buttons, pause button */

    }

    /* TODO: Handle micro profiles on tvOS. */

    /* This will be set when the first button press of the controller is

     * detected. */

    controller.playerIndex = -1;

#endif

}

static void

SDL_SYS_AddJoystickDevice(GCController *controller, SDL_bool accelerometer)

{

    SDL_JoystickDeviceItem *device = deviceList;

    while (device != NULL) {

        if (device->controller == controller) {

            return;

        }

        device = device->next;

    }

    device = (SDL_JoystickDeviceItem *) SDL_malloc(sizeof(SDL_JoystickDeviceItem));

    if (device == NULL) {

        return;

    }

    SDL_zerop(device);

    device->accelerometer = accelerometer;

    device->instance_id = instancecounter++;

    if (accelerometer) {

        device->name = SDL_strdup(accelerometerName);

        device->naxes = 3; /* Device acceleration in the x, y, and z axes. */

        device->nhats = 0;

        device->nbuttons = 0;

        /* Use the accelerometer name as a GUID. */

        SDL_memcpy(&device->guid.data, device->name, SDL_min(sizeof(SDL_JoystickGUID), SDL_strlen(device->name)));

    } else if (controller) {

        SDL_SYS_AddMFIJoystickDevice(device, controller);

    }

    if (deviceList == NULL) {

        deviceList = device;

    } else {

        SDL_JoystickDeviceItem *lastdevice = deviceList;

        while (lastdevice->next != NULL) {

            lastdevice = lastdevice->next;

        }

        lastdevice->next = device;

    }

    ++numjoysticks;

}

static SDL_JoystickDeviceItem *

SDL_SYS_RemoveJoystickDevice(SDL_JoystickDeviceItem *device)

{

    SDL_JoystickDeviceItem *prev = NULL;

    SDL_JoystickDeviceItem *next = NULL;

    SDL_JoystickDeviceItem *item = deviceList;

    if (device == NULL) {

        return NULL;

    }

    next = device->next;

    while (item != NULL) {

        if (item == device) {

            break;

        }

        prev = item;

        item = item->next;

    }

    /* Unlink the device item from the device list. */

    if (prev) {

        prev->next = device->next;

    } else if (device == deviceList) {

        deviceList = device->next;

    }

    if (device->joystick) {

        device->joystick->hwdata = NULL;

    }

#ifdef SDL_JOYSTICK_MFI

    @autoreleasepool {

        if (device->controller) {

            /* The controller was explicitly retained in the struct, so it

             * should be explicitly released before freeing the struct. */

            GCController *controller = CFBridgingRelease((__bridge CFTypeRef)(device->controller));

            controller.controllerPausedHandler = nil;

            device->controller = nil;

        }

    }

#endif /* SDL_JOYSTICK_MFI */

    --numjoysticks;

    SDL_free(device->name);

    SDL_free(device);

    return next;

}

/* Function to scan the system for joysticks.

 * Joystick 0 should be the system default joystick.

 * It should return 0, or -1 on an unrecoverable fatal error.

 */

int

SDL_SYS_JoystickInit(void)

{

    @autoreleasepool {

        NSNotificationCenter *center = [NSNotificationCenter defaultCenter];

        const char *hint = SDL_GetHint(SDL_HINT_ACCELEROMETER_AS_JOYSTICK);

        if (!hint || SDL_atoi(hint)) {

            /* Default behavior, accelerometer as joystick */

            SDL_SYS_AddJoystickDevice(nil, SDL_TRUE);

        }

#ifdef SDL_JOYSTICK_MFI

        /* GameController.framework was added in iOS 7. */

        if (![GCController class]) {

            return numjoysticks;

        }

        for (GCController *controller in [GCController controllers]) {

            SDL_SYS_AddJoystickDevice(controller, SDL_FALSE);

        }

        connectObserver = [center addObserverForName:GCControllerDidConnectNotification

                                              object:nil

                                               queue:nil

                                          usingBlock:^(NSNotification *note) {

                                              GCController *controller = note.object;

                                              SDL_SYS_AddJoystickDevice(controller, SDL_FALSE);

                                          }];

        disconnectObserver = [center addObserverForName:GCControllerDidDisconnectNotification

                                                 object:nil

                                                  queue:nil

                                             usingBlock:^(NSNotification *note) {

                                                 GCController *controller = note.object;

                                                 SDL_JoystickDeviceItem *device = deviceList;

                                                 while (device != NULL) {

                                                     if (device->controller == controller) {

                                                         SDL_SYS_RemoveJoystickDevice(device);

                                                         break;

                                                     }

                                                     device = device->next;

                                                 }

                                             }];

#endif /* SDL_JOYSTICK_MFI */

    }

    return numjoysticks;

}

int SDL_SYS_NumJoysticks()

{

    return numjoysticks;

}

void SDL_SYS_JoystickDetect()

{

}

/* Function to get the device-dependent name of a joystick */

const char *

SDL_SYS_JoystickNameForDeviceIndex(int device_index)

{

    SDL_JoystickDeviceItem *device = GetDeviceForIndex(device_index);

    return device ? device->name : "Unknown";

}

/* Function to perform the mapping from device index to the instance id for this index */

SDL_JoystickID SDL_SYS_GetInstanceIdOfDeviceIndex(int device_index)

{

    SDL_JoystickDeviceItem *device = GetDeviceForIndex(device_index);

    return device ? device->instance_id : 0;

}

/* Function to open a joystick for use.

   The joystick to open is specified by the device index.

   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, int device_index)

{

    SDL_JoystickDeviceItem *device = GetDeviceForIndex(device_index);

    if (device == NULL) {

        return SDL_SetError("Could not open Joystick: no hardware device for the specified index");

    }

    joystick->hwdata = device;

    joystick->instance_id = device->instance_id;

    joystick->naxes = device->naxes;

    joystick->nhats = device->nhats;

    joystick->nbuttons = device->nbuttons;

    joystick->nballs = 0;

    device->joystick = joystick;

    @autoreleasepool {

        if (device->accelerometer) {

            if (motionManager == nil) {

                motionManager = [[CMMotionManager alloc] init];

            }

            /* Shorter times between updates can significantly increase CPU usage. */

            motionManager.accelerometerUpdateInterval = 0.1;

            [motionManager startAccelerometerUpdates];

        } else {

#ifdef SDL_JOYSTICK_MFI

            GCController *controller = device->controller;

            controller.controllerPausedHandler = ^(GCController *c) {

                if (joystick->hwdata) {

                    ++joystick->hwdata->num_pause_presses;

                }

            };

#endif /* SDL_JOYSTICK_MFI */

        }

    }

    return 0;

}

/* Function to determine if this joystick is attached to the system right now */

SDL_bool

SDL_SYS_JoystickAttached(SDL_Joystick *joystick)

{

    return joystick->hwdata != NULL;

}

static void

SDL_SYS_AccelerometerUpdate(SDL_Joystick * joystick)

{

    const float maxgforce = SDL_IPHONE_MAX_GFORCE;

    const SInt16 maxsint16 = 0x7FFF;

    CMAcceleration accel;

    @autoreleasepool {

        if (!motionManager.isAccelerometerActive) {

            return;

        }

        accel = motionManager.accelerometerData.acceleration;

    }

    /*

     Convert accelerometer data from floating point to Sint16, which is what

     the joystick system expects.

     To do the conversion, the data is first clamped onto the interval

     [-SDL_IPHONE_MAX_G_FORCE, SDL_IPHONE_MAX_G_FORCE], then the data is multiplied

     by MAX_SINT16 so that it is mapped to the full range of an Sint16.

     You can customize the clamped range of this function by modifying the

     SDL_IPHONE_MAX_GFORCE macro in SDL_config_iphoneos.h.

     Once converted to Sint16, the accelerometer data no longer has coherent

     units. You can convert the data back to units of g-force by multiplying

     it in your application's code by SDL_IPHONE_MAX_GFORCE / 0x7FFF.

     */

    /* clamp the data */

    accel.x = SDL_min(SDL_max(accel.x, -maxgforce), maxgforce);

    accel.y = SDL_min(SDL_max(accel.y, -maxgforce), maxgforce);

    accel.z = SDL_min(SDL_max(accel.z, -maxgforce), maxgforce);

    /* pass in data mapped to range of SInt16 */

    SDL_PrivateJoystickAxis(joystick, 0,  (accel.x / maxgforce) * maxsint16);

    SDL_PrivateJoystickAxis(joystick, 1, -(accel.y / maxgforce) * maxsint16);

    SDL_PrivateJoystickAxis(joystick, 2,  (accel.z / maxgforce) * maxsint16);

}

#ifdef SDL_JOYSTICK_MFI

static Uint8

SDL_SYS_MFIJoystickHatStateForDPad(GCControllerDirectionPad *dpad)

{

    Uint8 hat = 0;

    if (dpad.up.isPressed) {

        hat |= SDL_HAT_UP;

    } else if (dpad.down.isPressed) {

        hat |= SDL_HAT_DOWN;

    }

    if (dpad.left.isPressed) {

        hat |= SDL_HAT_LEFT;

    } else if (dpad.right.isPressed) {

        hat |= SDL_HAT_RIGHT;

    }

    if (hat == 0) {

        return SDL_HAT_CENTERED;

    }

    return hat;

}

#endif

static void

SDL_SYS_MFIJoystickUpdate(SDL_Joystick * joystick)

{

#ifdef SDL_JOYSTICK_MFI

    @autoreleasepool {

        GCController *controller = joystick->hwdata->controller;

        Uint8 hatstate = SDL_HAT_CENTERED;

        int i;

        int updateplayerindex = 0;

        if (controller.extendedGamepad) {

            GCExtendedGamepad *gamepad = controller.extendedGamepad;

            /* Axis order matches the XInput Windows mappings. */

            Sint16 axes[] = {

                (Sint16) (gamepad.leftThumbstick.xAxis.value * 32767),

                (Sint16) (gamepad.leftThumbstick.yAxis.value * -32767),

                (Sint16) ((gamepad.leftTrigger.value * 65535) - 32768),

                (Sint16) (gamepad.rightThumbstick.xAxis.value * 32767),

                (Sint16) (gamepad.rightThumbstick.yAxis.value * -32767),

                (Sint16) ((gamepad.rightTrigger.value * 65535) - 32768),

            };

            /* Button order matches the XInput Windows mappings. */

            Uint8 buttons[] = {

                gamepad.buttonA.isPressed, gamepad.buttonB.isPressed,

                gamepad.buttonX.isPressed, gamepad.buttonY.isPressed,

                gamepad.leftShoulder.isPressed,

                gamepad.rightShoulder.isPressed,

            };

            hatstate = SDL_SYS_MFIJoystickHatStateForDPad(gamepad.dpad);

            for (i = 0; i < SDL_arraysize(axes); i++) {

                /* The triggers (axes 2 and 5) are resting at -32768 but SDL

                 * initializes its values to 0. We only want to make sure the

                 * player index is up to date if the user actually moves an axis. */

                if ((i != 2 && i != 5) || axes[i] != -32768) {

                    updateplayerindex |= (joystick->axes[i] != axes[i]);

                }

                SDL_PrivateJoystickAxis(joystick, i, axes[i]);

            }

            for (i = 0; i < SDL_arraysize(buttons); i++) {

                updateplayerindex |= (joystick->buttons[i] != buttons[i]);

                SDL_PrivateJoystickButton(joystick, i, buttons[i]);

            }

        } else if (controller.gamepad) {

            GCGamepad *gamepad = controller.gamepad;

            /* Button order matches the XInput Windows mappings. */

            Uint8 buttons[] = {

                gamepad.buttonA.isPressed, gamepad.buttonB.isPressed,

                gamepad.buttonX.isPressed, gamepad.buttonY.isPressed,

                gamepad.leftShoulder.isPressed,

                gamepad.rightShoulder.isPressed,

            };

            hatstate = SDL_SYS_MFIJoystickHatStateForDPad(gamepad.dpad);

            for (i = 0; i < SDL_arraysize(buttons); i++) {

                updateplayerindex |= (joystick->buttons[i] != buttons[i]);

                SDL_PrivateJoystickButton(joystick, i, buttons[i]);

            }

        }

        /* TODO: Handle micro profiles on tvOS. */

        if (joystick->nhats > 0) {