/*  RetroArch - A frontend for libretro.
 *  Copyright (C) 2010-2014 - Hans-Kristian Arntzen
 *  Copyright (C) 2011-2017 - Daniel De Matteis
 *
 *  RetroArch is free software: you can redistribute it and/or modify it under the terms
 *  of the GNU General Public License as published by the Free Software Found-
 *  ation, either version 3 of the License, or (at your option) any later version.
 *
 *  RetroArch 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along with RetroArch.
 *  If not, see <http://www.gnu.org/licenses/>.
 */
#include <stdint.h>
#include <unistd.h>
#include <string.h>
#include <limits.h>
#include <errno.h>

#include <boolean.h>

#include <AvailabilityMacros.h>

#include "../../tasks/tasks_internal.h"

#import <GameController/GameController.h>

#ifndef MAX_MFI_CONTROLLERS
#define MAX_MFI_CONTROLLERS 4
#endif

static uint32_t mfi_buttons[MAX_USERS];
static int16_t  mfi_axes[MAX_USERS][4];

static uint32_t mfi_controllers[MAX_MFI_CONTROLLERS];

static NSMutableArray *mfiControllers;

enum
{
    GCCONTROLLER_PLAYER_INDEX_UNSET = -1,
};

static bool apple_gamecontroller_available(void)
{
    int major, minor;
    get_ios_version(&major, &minor);

    if (major <= 6)
        return false;

    return true;
}

static void apple_gamecontroller_joypad_poll_internal(GCController *controller)
{
    uint32_t slot, pause, select, l3, r3;
    uint32_t *buttons;
    if (!controller)
        return;

    slot               = (uint32_t)controller.playerIndex;
    buttons            = &mfi_buttons[slot];

    /* retain the values from the paused controller handler and pass them through */
    if (@available(iOS 13, *))
    {
        // The menu button can be pressed/unpressed like any other button in iOS 13
        // so no need to passthrough anything
        *buttons = 0;
    }
    else
    {
        // Use the paused controller handler for iOS versions below 13
        pause              = *buttons & (1 << RETRO_DEVICE_ID_JOYPAD_START);
        select             = *buttons & (1 << RETRO_DEVICE_ID_JOYPAD_SELECT);
        l3                 = *buttons & ( 1 << RETRO_DEVICE_ID_JOYPAD_L3 );
        r3                 = *buttons & ( 1 << RETRO_DEVICE_ID_JOYPAD_R3 );
        *buttons           = 0 | pause | select | l3 | r3;
    }
    memset(mfi_axes[slot], 0, sizeof(mfi_axes[0]));

    if (controller.extendedGamepad)
    {
        GCExtendedGamepad *gp = (GCExtendedGamepad *)controller.extendedGamepad;

        *buttons             |= gp.dpad.up.pressed         ? (1 << RETRO_DEVICE_ID_JOYPAD_UP)    : 0;
        *buttons             |= gp.dpad.down.pressed       ? (1 << RETRO_DEVICE_ID_JOYPAD_DOWN)  : 0;
        *buttons             |= gp.dpad.left.pressed       ? (1 << RETRO_DEVICE_ID_JOYPAD_LEFT)  : 0;
        *buttons             |= gp.dpad.right.pressed      ? (1 << RETRO_DEVICE_ID_JOYPAD_RIGHT) : 0;
        *buttons             |= gp.buttonA.pressed         ? (1 << RETRO_DEVICE_ID_JOYPAD_B)     : 0;
        *buttons             |= gp.buttonB.pressed         ? (1 << RETRO_DEVICE_ID_JOYPAD_A)     : 0;
        *buttons             |= gp.buttonX.pressed         ? (1 << RETRO_DEVICE_ID_JOYPAD_Y)     : 0;
        *buttons             |= gp.buttonY.pressed         ? (1 << RETRO_DEVICE_ID_JOYPAD_X)     : 0;
        *buttons             |= gp.leftShoulder.pressed    ? (1 << RETRO_DEVICE_ID_JOYPAD_L)     : 0;
        *buttons             |= gp.rightShoulder.pressed   ? (1 << RETRO_DEVICE_ID_JOYPAD_R)     : 0;
        *buttons             |= gp.leftTrigger.pressed     ? (1 << RETRO_DEVICE_ID_JOYPAD_L2)    : 0;
        *buttons             |= gp.rightTrigger.pressed    ? (1 << RETRO_DEVICE_ID_JOYPAD_R2)    : 0;
#if __IPHONE_OS_VERSION_MAX_ALLOWED >= 120100 || __TV_OS_VERSION_MAX_ALLOWED >= 120100
        if (@available(iOS 12.1, *)) {
            *buttons         |= gp.leftThumbstickButton.pressed ? (1 << RETRO_DEVICE_ID_JOYPAD_L3) : 0;
            *buttons         |= gp.rightThumbstickButton.pressed ? (1 << RETRO_DEVICE_ID_JOYPAD_R3) : 0;
        }
#endif

#if __IPHONE_OS_VERSION_MAX_ALLOWED >= 130000 || __TV_OS_VERSION_MAX_ALLOWED >= 130000
        if (@available(iOS 13, *))
        {
            // Support "Options" button present in PS4 / XBox One controllers
            *buttons         |= gp.buttonOptions.pressed ? (1 << RETRO_DEVICE_ID_JOYPAD_SELECT) : 0;
            
            // Support buttons that aren't supported by older mFi controller via "hotkey" combinations:
            //
            // LS + Menu => Select
            // LT + Menu => L3
            // RT + Menu => R3
            if ( gp.buttonMenu.pressed ) {
                if ( gp.leftShoulder.pressed ) {
                    *buttons     |= 1 << RETRO_DEVICE_ID_JOYPAD_SELECT;
                } else if ( gp.leftTrigger.pressed ) {
                    *buttons     |= 1 << RETRO_DEVICE_ID_JOYPAD_L3;
                } else if ( gp.rightTrigger.pressed ) {
                    *buttons     |= 1 << RETRO_DEVICE_ID_JOYPAD_R3;
                } else {
                    *buttons     |= 1 << RETRO_DEVICE_ID_JOYPAD_START;
                }
            }
        }
#endif

        mfi_axes[slot][0]     = gp.leftThumbstick.xAxis.value * 32767.0f;
        mfi_axes[slot][1]     = gp.leftThumbstick.yAxis.value * 32767.0f;
        mfi_axes[slot][2]     = gp.rightThumbstick.xAxis.value * 32767.0f;
        mfi_axes[slot][3]     = gp.rightThumbstick.yAxis.value * 32767.0f;

    }
    else if (controller.gamepad)
    {
        GCGamepad *gp = (GCGamepad *)controller.gamepad;

        *buttons |= gp.dpad.up.pressed       ? (1 << RETRO_DEVICE_ID_JOYPAD_UP)    : 0;
        *buttons |= gp.dpad.down.pressed     ? (1 << RETRO_DEVICE_ID_JOYPAD_DOWN)  : 0;
        *buttons |= gp.dpad.left.pressed     ? (1 << RETRO_DEVICE_ID_JOYPAD_LEFT)  : 0;
        *buttons |= gp.dpad.right.pressed    ? (1 << RETRO_DEVICE_ID_JOYPAD_RIGHT) : 0;
        *buttons |= gp.buttonA.pressed       ? (1 << RETRO_DEVICE_ID_JOYPAD_B)     : 0;
        *buttons |= gp.buttonB.pressed       ? (1 << RETRO_DEVICE_ID_JOYPAD_A)     : 0;
        *buttons |= gp.buttonX.pressed       ? (1 << RETRO_DEVICE_ID_JOYPAD_Y)     : 0;
        *buttons |= gp.buttonY.pressed       ? (1 << RETRO_DEVICE_ID_JOYPAD_X)     : 0;
        *buttons |= gp.leftShoulder.pressed  ? (1 << RETRO_DEVICE_ID_JOYPAD_L)     : 0;
        *buttons |= gp.rightShoulder.pressed ? (1 << RETRO_DEVICE_ID_JOYPAD_R)     : 0;
    }
}

static void apple_gamecontroller_joypad_poll(void)
{
    if (!apple_gamecontroller_available())
        return;

    for (GCController *controller in [GCController controllers])
        apple_gamecontroller_joypad_poll_internal(controller);
}

static void apple_gamecontroller_joypad_register(GCGamepad *gamepad)
{
    gamepad.valueChangedHandler = ^(GCGamepad *updateGamepad, GCControllerElement *element)
    {
        apple_gamecontroller_joypad_poll_internal(updateGamepad.controller);
    };

    if (@available(iOS 13, *)) {
        // controllerPausedHandler is deprecated in favor of being able to deal with the menu
        // button as any other button
        return;
    } else {
        gamepad.controller.controllerPausedHandler = ^(GCController *controller)
        {
            uint32_t slot      = (uint32_t)controller.playerIndex;
            
            // Support buttons that aren't supported by the mFi controller via "hotkey" combinations:
            //
            // LS + Menu => Select
            // LT + Menu => L3
            // RT + Menu => R3
            // Note that these are just button presses, and it does not simulate holding down the button
            if ( controller.gamepad.leftShoulder.pressed || controller.extendedGamepad.leftShoulder.pressed ) {
                mfi_buttons[slot] &= ~(1 << RETRO_DEVICE_ID_JOYPAD_START);
                mfi_buttons[slot] &= ~(1 << RETRO_DEVICE_ID_JOYPAD_L);
                mfi_buttons[slot] |= (1 << RETRO_DEVICE_ID_JOYPAD_SELECT);
                dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.1 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
                    mfi_buttons[slot] &= ~(1 << RETRO_DEVICE_ID_JOYPAD_SELECT);
                });
                return;
            }
            if ( controller.extendedGamepad.leftTrigger.pressed ) {
                mfi_buttons[slot] &= ~(1 << RETRO_DEVICE_ID_JOYPAD_L2);
                mfi_buttons[slot] &= ~(1 << RETRO_DEVICE_ID_JOYPAD_START);
                mfi_buttons[slot] |= (1 << RETRO_DEVICE_ID_JOYPAD_L3);
                dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.1 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
                    mfi_buttons[slot] &= ~(1 << RETRO_DEVICE_ID_JOYPAD_L3);
                });
                return;
            }
            if ( controller.extendedGamepad.rightTrigger.pressed ) {
                mfi_buttons[slot] &= ~(1 << RETRO_DEVICE_ID_JOYPAD_R2);
                mfi_buttons[slot] &= ~(1 << RETRO_DEVICE_ID_JOYPAD_START);
                mfi_buttons[slot] |= (1 << RETRO_DEVICE_ID_JOYPAD_R3);
                dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.1 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
                    mfi_buttons[slot] &= ~(1 << RETRO_DEVICE_ID_JOYPAD_R3);
                });
                return;
            }
            
            mfi_buttons[slot] |= (1 << RETRO_DEVICE_ID_JOYPAD_START);
            
            dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.1 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
                mfi_buttons[slot] &= ~(1 << RETRO_DEVICE_ID_JOYPAD_START);
            });
            
        };
    }
}

static void mfi_joypad_autodetect_add(unsigned autoconf_pad)
{
    input_autoconfigure_connect("mFi Controller", NULL, mfi_joypad.ident, autoconf_pad, 0, 0);
}

static void apple_gamecontroller_joypad_connect(GCController *controller)
{
    signed desired_index = (int32_t)controller.playerIndex;
    desired_index        = (desired_index >= 0 && desired_index < MAX_MFI_CONTROLLERS)
    ? desired_index : 0;

    /* prevent same controller getting set twice */
    if ( [mfiControllers containsObject:controller] ) {
        return;
    }
    if (mfi_controllers[desired_index] != (uint32_t)controller.hash)
    {
        /* desired slot is unused, take it */
        if (!mfi_controllers[desired_index])
        {
            controller.playerIndex = desired_index;
            mfi_controllers[desired_index] = (uint32_t)controller.hash;
        }
        else
        {
            /* find a new slot for this controller that's unused */
            unsigned i;

            for (i = 0; i < MAX_MFI_CONTROLLERS; ++i)
            {
                if (mfi_controllers[i])
                    continue;

                mfi_controllers[i] = (uint32_t)controller.hash;
                controller.playerIndex = i;
                break;
            }
        }

        [mfiControllers addObject:controller];
        // move any non-game controllers (like the siri remote) to the end
        if ( mfiControllers.count > 1 ) {
            NSInteger connectedNonGameControllerIndex = NSNotFound;
            NSUInteger index = 0;
            for (GCController *connectedController in mfiControllers) {
                if ( connectedController.gamepad == nil && connectedController.extendedGamepad == nil ) {
                    connectedNonGameControllerIndex = index;
                }
                index++;
            }
            if ( connectedNonGameControllerIndex != NSNotFound ) {
                GCController *nonGameController = [mfiControllers objectAtIndex:connectedNonGameControllerIndex];
                [mfiControllers removeObjectAtIndex:connectedNonGameControllerIndex];
                [mfiControllers addObject:nonGameController];
            }
            int newPlayerIndex = 0;
            for (GCController *gc in mfiControllers) {
                gc.playerIndex = newPlayerIndex++;
            }
        }

        apple_gamecontroller_joypad_register(controller.gamepad);
        mfi_joypad_autodetect_add(controller.playerIndex);
    }
}

static void apple_gamecontroller_joypad_disconnect(GCController* controller)
{
    signed pad = (int32_t)controller.playerIndex;

    if (pad == GCCONTROLLER_PLAYER_INDEX_UNSET)
        return;

    mfi_controllers[pad] = 0;
    if ( [mfiControllers containsObject:controller] )
    {
        [mfiControllers removeObject:controller];
        input_autoconfigure_disconnect(pad, mfi_joypad.ident);
    }
}

bool apple_gamecontroller_joypad_init(void *data)
{
    static bool inited = false;
    if (inited)
        return true;
    if (!apple_gamecontroller_available())
        return false;
    mfiControllers = [[NSMutableArray alloc] initWithCapacity:MAX_MFI_CONTROLLERS];
#ifdef __IPHONE_7_0
    [[NSNotificationCenter defaultCenter] addObserverForName:GCControllerDidConnectNotification
                                                      object:nil
                                                       queue:[NSOperationQueue mainQueue]
                                                  usingBlock:^(NSNotification *note)
     {
         apple_gamecontroller_joypad_connect([note object]);
     }];
    [[NSNotificationCenter defaultCenter] addObserverForName:GCControllerDidDisconnectNotification
                                                      object:nil
                                                       queue:[NSOperationQueue mainQueue]
                                                  usingBlock:^(NSNotification *note)
     {
         apple_gamecontroller_joypad_disconnect([note object]);
     } ];
#endif

    return true;
}

static void apple_gamecontroller_joypad_destroy(void)
{
}

static bool apple_gamecontroller_joypad_button(unsigned port, uint16_t joykey)
{
    /* Check hat. */
    if (GET_HAT_DIR(joykey))
        return false;
    /* Check the button. */
    if ((port < MAX_USERS) && (joykey < 32))
        return ((mfi_buttons[port] & (1 << joykey)) != 0);

    return false;
}

static void apple_gamecontroller_joypad_get_buttons(unsigned port,
                                                    input_bits_t *state)
{
    BITS_COPY16_PTR(state, mfi_buttons[port]);
}

static int16_t apple_gamecontroller_joypad_axis(unsigned port, uint32_t joyaxis)
{
    int16_t val   = 0;
    int16_t axis = -1;
    bool is_neg  = false;
    bool is_pos  = false;

    if (joyaxis == AXIS_NONE)
        return 0;

    if (AXIS_NEG_GET(joyaxis) < 4)
    {
        axis  = AXIS_NEG_GET(joyaxis);
        is_neg = true;
    }
    else if(AXIS_POS_GET(joyaxis) < 4)
    {
        axis  = AXIS_POS_GET(joyaxis);
        is_pos = true;
    }

    switch (axis)
    {
        case 0:
            val = mfi_axes[port][0];
            break;
        case 1:
            val = mfi_axes[port][1];
            break;
        case 2:
            val = mfi_axes[port][2];
            break;
        case 3:
            val = mfi_axes[port][3];
            break;
    }

    if (is_neg && val > 0)
        val = 0;
    else if (is_pos && val < 0)
        val = 0;

    return val;
}

static bool apple_gamecontroller_joypad_query_pad(unsigned pad)
{
    return pad < MAX_USERS;
}

static const char *apple_gamecontroller_joypad_name(unsigned pad)
{
    if (pad >= MAX_USERS)
        return NULL;

    return "mFi Controller";
}

input_device_driver_t mfi_joypad = {
    apple_gamecontroller_joypad_init,
    apple_gamecontroller_joypad_query_pad,
    apple_gamecontroller_joypad_destroy,
    apple_gamecontroller_joypad_button,
    apple_gamecontroller_joypad_get_buttons,
    apple_gamecontroller_joypad_axis,
    apple_gamecontroller_joypad_poll,
    NULL,
    apple_gamecontroller_joypad_name,
    "mfi",
};