/*

  Simple DirectMedia Layer

  Copyright (C) 1997-2014 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"

#ifdef SDL_HAPTIC_LINUX

#include "SDL_assert.h"

#include "SDL_haptic.h"

#include "../SDL_syshaptic.h"

#include "SDL_joystick.h"

#include "../../joystick/SDL_sysjoystick.h"     /* For the real SDL_Joystick */

#include "../../joystick/linux/SDL_sysjoystick_c.h"     /* For joystick hwdata */

#include "../../core/linux/SDL_udev.h"

#include <unistd.h>             /* close */

#include <linux/input.h>        /* Force feedback linux stuff. */

#include <fcntl.h>              /* O_RDWR */

#include <limits.h>             /* INT_MAX */

#include <errno.h>              /* errno, strerror */

#include <math.h>               /* atan2 */

#include <sys/stat.h>           /* stat */

/* Just in case. */

#ifndef M_PI

#  define M_PI     3.14159265358979323846

#endif

#define MAX_HAPTICS  32         /* It's doubtful someone has more then 32 evdev */

static int MaybeAddDevice(const char *path);

#if SDL_USE_LIBUDEV

static int MaybeRemoveDevice(const char *path);

void haptic_udev_callback(SDL_UDEV_deviceevent udev_type, int udev_class, const char *devpath);

#endif /* SDL_USE_LIBUDEV */

/*

 * List of available haptic devices.

 */

typedef struct SDL_hapticlist_item

{

    char *fname;                /* Dev path name (like /dev/input/event1) */

    SDL_Haptic *haptic;         /* Associated haptic. */

    struct SDL_hapticlist_item *next;

} SDL_hapticlist_item;

/*

 * Haptic system hardware data.

 */

struct haptic_hwdata

{

    int fd;                     /* File descriptor of the device. */

    char *fname;                /* Points to the name in SDL_hapticlist. */

};

/*

 * Haptic system effect data.

 */

struct haptic_hweffect

{

    struct ff_effect effect;    /* The linux kernel effect structure. */

};

static SDL_hapticlist_item *SDL_hapticlist = NULL;

static SDL_hapticlist_item *SDL_hapticlist_tail = NULL;

static int numhaptics = 0;

#define test_bit(nr, addr) \

   (((1UL << ((nr) & 31)) & (((const unsigned int *) addr)[(nr) >> 5])) != 0)

#define EV_TEST(ev,f) \

   if (test_bit((ev), features)) ret |= (f);

/*

 * Test whether a device has haptic properties.

 * Returns available properties or 0 if there are none.

 */

static int

EV_IsHaptic(int fd)

{

    unsigned int ret;

    unsigned long features[1 + FF_MAX / sizeof(unsigned long)];

    /* Ask device for what it has. */

    ret = 0;

    if (ioctl(fd, EVIOCGBIT(EV_FF, sizeof(features)), features) < 0) {

        return SDL_SetError("Haptic: Unable to get device's features: %s",

                            strerror(errno));

    }

    /* Convert supported features to SDL_HAPTIC platform-neutral features. */

    EV_TEST(FF_CONSTANT, SDL_HAPTIC_CONSTANT);

    EV_TEST(FF_SINE, SDL_HAPTIC_SINE);

    /* !!! FIXME: put this back when we have more bits in 2.1 */

    /* EV_TEST(FF_SQUARE, SDL_HAPTIC_SQUARE); */

    EV_TEST(FF_TRIANGLE, SDL_HAPTIC_TRIANGLE);

    EV_TEST(FF_SAW_UP, SDL_HAPTIC_SAWTOOTHUP);

    EV_TEST(FF_SAW_DOWN, SDL_HAPTIC_SAWTOOTHDOWN);

    EV_TEST(FF_RAMP, SDL_HAPTIC_RAMP);

    EV_TEST(FF_SPRING, SDL_HAPTIC_SPRING);

    EV_TEST(FF_FRICTION, SDL_HAPTIC_FRICTION);

    EV_TEST(FF_DAMPER, SDL_HAPTIC_DAMPER);

    EV_TEST(FF_INERTIA, SDL_HAPTIC_INERTIA);

    EV_TEST(FF_CUSTOM, SDL_HAPTIC_CUSTOM);

    EV_TEST(FF_GAIN, SDL_HAPTIC_GAIN);

    EV_TEST(FF_AUTOCENTER, SDL_HAPTIC_AUTOCENTER);

    EV_TEST(FF_RUMBLE, SDL_HAPTIC_LEFTRIGHT);

    /* Return what it supports. */

    return ret;

}

/*

 * Tests whether a device is a mouse or not.

 */

static int

EV_IsMouse(int fd)

{

    unsigned long argp[40];

    /* Ask for supported features. */

    if (ioctl(fd, EVIOCGBIT(EV_KEY, sizeof(argp)), argp) < 0) {

        return -1;

    }

    /* Currently we only test for BTN_MOUSE which can give fake positives. */

    if (test_bit(BTN_MOUSE, argp) != 0) {

        return 1;

    }

    return 0;

}

/*

 * Initializes the haptic subsystem by finding available devices.

 */

int

SDL_SYS_HapticInit(void)

{

    const char joydev_pattern[] = "/dev/input/event%d";

    char path[PATH_MAX];

    int i, j;

    /*

     * Limit amount of checks to MAX_HAPTICS since we may or may not have

     * permission to some or all devices.

     */

    i = 0;

    for (j = 0; j < MAX_HAPTICS; ++j) {

        snprintf(path, PATH_MAX, joydev_pattern, i++);

        MaybeAddDevice(path);

    }

#if SDL_USE_LIBUDEV

    if (SDL_UDEV_Init() < 0) {

        return SDL_SetError("Could not initialize UDEV");

    }

    if ( SDL_UDEV_AddCallback(haptic_udev_callback) < 0) {

        SDL_UDEV_Quit();

        return SDL_SetError("Could not setup haptic <-> udev callback");

    }

#endif /* SDL_USE_LIBUDEV */

    return numhaptics;

}

int

SDL_SYS_NumHaptics()

{

    return numhaptics;

}

static SDL_hapticlist_item *

HapticByDevIndex(int device_index)

{

    SDL_hapticlist_item *item = SDL_hapticlist;

    if ((device_index < 0) || (device_index >= numhaptics)) {

        return NULL;

    }

    while (device_index > 0) {

        SDL_assert(item != NULL);

        --device_index;

        item = item->next;

    }

    return item;

}

#if SDL_USE_LIBUDEV

void haptic_udev_callback(SDL_UDEV_deviceevent udev_type, int udev_class, const char *devpath)

{

    if (devpath == NULL || !(udev_class & SDL_UDEV_DEVICE_JOYSTICK)) {

        return;

    }

    switch( udev_type )

    {

        case SDL_UDEV_DEVICEADDED:

            MaybeAddDevice(devpath);

            break;

        case SDL_UDEV_DEVICEREMOVED:

            MaybeRemoveDevice(devpath);

            break;

        default:

            break;

    }

}

#endif /* SDL_USE_LIBUDEV */

static int

MaybeAddDevice(const char *path)

{

    dev_t dev_nums[MAX_HAPTICS];

    struct stat sb;

    int fd;

    int k;

    int duplicate;

    int success;

    SDL_hapticlist_item *item;

    if (path == NULL) {

        return -1;

    }

    /* check to see if file exists */

    if (stat(path, &sb) != 0) {

        return -1;

    }

    /* check for duplicates */

    duplicate = 0;

    for (k = 0; (k < numhaptics) && !duplicate; ++k) {

        if (sb.st_rdev == dev_nums[k]) {

            duplicate = 1;

        }

    }

    if (duplicate) {

        return -1;

    }

    /* try to open */

    fd = open(path, O_RDWR, 0);

    if (fd < 0) {

        return -1;

    }

#ifdef DEBUG_INPUT_EVENTS

    printf("Checking %s\n", path);

#endif

    /* see if it works */

    success = EV_IsHaptic(fd);

    close(fd);

    if (success <= 0) {

        return -1;

    }

    item = (SDL_hapticlist_item *) SDL_calloc(1, sizeof (SDL_hapticlist_item));

    if (item == NULL) {

        return -1;

    }

    item->fname = SDL_strdup(path);

    if ( (item->fname == NULL) ) {

        SDL_free(item->fname);

        SDL_free(item);

        return -1;

    }

    /* TODO: should we add instance IDs? */

    if (SDL_hapticlist_tail == NULL) {

        SDL_hapticlist = SDL_hapticlist_tail = item;

    } else {

        SDL_hapticlist_tail->next = item;

        SDL_hapticlist_tail = item;

    }

    dev_nums[numhaptics] = sb.st_rdev;

    ++numhaptics;

    /* !!! TODO: Send a haptic add event? */

    return numhaptics;

}

#if SDL_USE_LIBUDEV

static int

MaybeRemoveDevice(const char* path)

{

    SDL_hapticlist_item *item;

    SDL_hapticlist_item *prev = NULL;

    if (path == NULL) {

        return -1;

    }

    for (item = SDL_hapticlist; item != NULL; item = item->next) {

        /* found it, remove it. */

        if (SDL_strcmp(path, item->fname) == 0) {

            const int retval = item->haptic ? item->haptic->index : -1;

            if (prev != NULL) {

                prev->next = item->next;

            } else {

                SDL_assert(SDL_hapticlist == item);

                SDL_hapticlist = item->next;

            }

            if (item == SDL_hapticlist_tail) {

                SDL_hapticlist_tail = prev;

            }

            /* Need to decrement the haptic count */

            --numhaptics;

            /* !!! TODO: Send a haptic remove event? */

            SDL_free(item->fname);

            SDL_free(item);

            return retval;

        }

        prev = item;

    }

    return -1;

}

#endif /* SDL_USE_LIBUDEV */

/*

 * Gets the name from a file descriptor.

 */

static const char *

SDL_SYS_HapticNameFromFD(int fd)

{

    static char namebuf[128];

    /* We use the evdev name ioctl. */

    if (ioctl(fd, EVIOCGNAME(sizeof(namebuf)), namebuf) <= 0) {

        return NULL;

    }

    return namebuf;

}

/*

 * Return the name of a haptic device, does not need to be opened.

 */

const char *

SDL_SYS_HapticName(int index)

{

    SDL_hapticlist_item *item;

    int fd;

    const char *name;

    item = HapticByDevIndex(index);

    /* Open the haptic device. */

    name = NULL;

    fd = open(item->fname, O_RDONLY, 0);

    if (fd >= 0) {

        name = SDL_SYS_HapticNameFromFD(fd);

        if (name == NULL) {

            /* No name found, return device character device */

            name = item->fname;

        }

    }

    close(fd);

    return name;

}

/*

 * Opens the haptic device from the file descriptor.

 */

static int

SDL_SYS_HapticOpenFromFD(SDL_Haptic * haptic, int fd)

{

    /* Allocate the hwdata */

    haptic->hwdata = (struct haptic_hwdata *)

        SDL_malloc(sizeof(*haptic->hwdata));

    if (haptic->hwdata == NULL) {

        SDL_OutOfMemory();

        goto open_err;

    }

    SDL_memset(haptic->hwdata, 0, sizeof(*haptic->hwdata));

    /* Set the data. */

    haptic->hwdata->fd = fd;

    haptic->supported = EV_IsHaptic(fd);

    haptic->naxes = 2;          /* Hardcoded for now, not sure if it's possible to find out. */

    /* Set the effects */

    if (ioctl(fd, EVIOCGEFFECTS, &haptic->neffects) < 0) {

        SDL_SetError("Haptic: Unable to query device memory: %s",

                     strerror(errno));

        goto open_err;

    }

    haptic->nplaying = haptic->neffects;        /* Linux makes no distinction. */

    haptic->effects = (struct haptic_effect *)

        SDL_malloc(sizeof(struct haptic_effect) * haptic->neffects);

    if (haptic->effects == NULL) {

        SDL_OutOfMemory();

        goto open_err;

    }

    /* Clear the memory */

    SDL_memset(haptic->effects, 0,

               sizeof(struct haptic_effect) * haptic->neffects);

    return 0;

    /* Error handling */

  open_err:

    close(fd);

    if (haptic->hwdata != NULL) {

        free(haptic->hwdata);

        haptic->hwdata = NULL;

    }

    return -1;

}

/*

 * Opens a haptic device for usage.

 */

int

SDL_SYS_HapticOpen(SDL_Haptic * haptic)

{

    int fd;

    int ret;

    SDL_hapticlist_item *item;

    item = HapticByDevIndex(haptic->index);

    /* Open the character device */

    fd = open(item->fname, O_RDWR, 0);

    if (fd < 0) {

        return SDL_SetError("Haptic: Unable to open %s: %s",

                            item->fname, strerror(errno));

    }

    /* Try to create the haptic. */

    ret = SDL_SYS_HapticOpenFromFD(haptic, fd); /* Already closes on error. */

    if (ret < 0) {

        return -1;

    }

    /* Set the fname. */

    haptic->hwdata->fname = item->fname;

    return 0;

}

/*

 * Opens a haptic device from first mouse it finds for usage.

 */

int

SDL_SYS_HapticMouse(void)

{

    int fd;

    int device_index = 0;

    SDL_hapticlist_item *item;

    for (item = SDL_hapticlist; item; item = item->next) {

        /* Open the device. */

        fd = open(item->fname, O_RDWR, 0);

        if (fd < 0) {

            return SDL_SetError("Haptic: Unable to open %s: %s",

                                item->fname, strerror(errno));

        }

        /* Is it a mouse? */

        if (EV_IsMouse(fd)) {

            close(fd);

            return device_index;

        }

        close(fd);