/*
    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
*/

#ifdef SAVE_RCSID
static char rcsid =
 "@(#) $Id$";
#endif

/* This is the system specific header for the SDL joystick API */

#include <stdio.h>		/* For the definition of NULL */
#include <stdlib.h>		/* For getenv() prototype */
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <limits.h>		/* For the definition of PATH_MAX */

#include <linux/joystick.h>
#ifdef USE_INPUT_EVENTS
#include <linux/input.h>
#endif

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

/* Define this if you want to map axes to hats and trackballs */
#define FANCY_HATS_AND_BALLS

#ifdef FANCY_HATS_AND_BALLS
/* Special joystick configurations:
	'JoystickName' Naxes Nhats Nballs
 */
static const char *special_joysticks[] = {
	"'MadCatz Panther XL' 3 2 1", /* We don't handle a rudder (axis 8) */
	"'SideWinder Precision Pro' 4 1 0",
	"'SideWinder 3D Pro' 4 1 0",
	"'Microsoft SideWinder 3D Pro' 4 1 0",
	"'Microsoft SideWinder Dual Strike USB version 1.0' 2 1 0",
	"'WingMan Interceptor' 3 3 0",
	/* WingMan Extreme Analog - not recognized by default
	"'Analog 3-axis 4-button joystick' 2 1 0",
	*/
	"'WingMan Extreme Digital 3D' 4 1 0",
	"'Analog 2-axis 4-button 1-hat FCS joystick' 2 1 0",
	NULL
};
#else
#undef USE_INPUT_EVENTS
#endif

/* The maximum number of joysticks we'll detect */
#define MAX_JOYSTICKS	32

/* A list of available joysticks */
static char *SDL_joylist[MAX_JOYSTICKS];

/* The private structure used to keep track of a joystick */
struct joystick_hwdata {
	int fd;
	/* The current linux joystick driver maps hats to two axes */
	int analog_hat;		/* Well, except for analog hats */
	struct hwdata_hat {
		int axis[2];
	} *hats;
	/* The current linux joystick driver maps balls to two axes */
	struct hwdata_ball {
		int axis[2];
	} *balls;

	/* Support for the Linux 2.4 unified input interface */
	SDL_bool is_hid;
#ifdef USE_INPUT_EVENTS
	Uint8 key_map[KEY_MAX-BTN_MISC];
	Uint8 abs_map[ABS_MAX];
	struct axis_correct {
		int used;
		int coef[3];
	} abs_correct[ABS_MAX];
#endif
};

static char *mystrdup(const char *string)
{
	char *newstring;

	newstring = (char *)malloc(strlen(string)+1);
	if ( newstring ) {
		strcpy(newstring, string);
	}
	return(newstring);
}

#ifdef USE_INPUT_EVENTS
#define test_bit(nr, addr) \
	(((1UL << ((nr) & 31)) & (((const unsigned int *) addr)[(nr) >> 5])) != 0)

static int EV_IsJoystick(int fd)
{
	unsigned long evbit[40];
	unsigned long keybit[40];
	unsigned long absbit[40];

	if ( (ioctl(fd, EVIOCGBIT(0, sizeof(evbit)), evbit) < 0) ||
	     (ioctl(fd, EVIOCGBIT(EV_KEY, sizeof(keybit)), keybit) < 0) ||
	     (ioctl(fd, EVIOCGBIT(EV_ABS, sizeof(absbit)), absbit) < 0) ) {
		return(0);
	}
	if (!(test_bit(EV_KEY, evbit) && test_bit(EV_ABS, evbit) &&
	      test_bit(ABS_X, absbit) && test_bit(ABS_Y, absbit) &&
	     (test_bit(BTN_TRIGGER, keybit) || test_bit(BTN_A, keybit) || test_bit(BTN_1, keybit)))) return 0;
	return(1);
}

#endif /* USE_INPUT_EVENTS */

/* Function to scan the system for joysticks */
int SDL_SYS_JoystickInit(void)
{
	/* The base path of the joystick devices */
	const char *joydev_pattern[] = {
		"/dev/js%d",
#ifdef USE_INPUT_EVENTS
		"/dev/input/event%d",
#endif
		"/dev/input/js%d"
	};
	int numjoysticks;
	int i, j, done;
	int fd;
	char path[PATH_MAX];
	dev_t dev_nums[MAX_JOYSTICKS];  /* major/minor device numbers */
	struct stat sb;
	int n, duplicate;

	numjoysticks = 0;

	/* First see if the user specified a joystick to use */
	if ( getenv("SDL_JOYSTICK_DEVICE") != NULL ) {
		strncpy(path, getenv("SDL_JOYSTICK_DEVICE"), sizeof(path));
		path[sizeof(path)-1] = '\0';
		if ( stat(path, &sb) == 0 ) {
			fd = open(path, O_RDONLY, 0);
			if ( fd >= 0 ) {
				/* Assume the user knows what they're doing. */
				SDL_joylist[numjoysticks] = mystrdup(path);
				if ( SDL_joylist[numjoysticks] ) {
					dev_nums[numjoysticks] = sb.st_rdev;
					++numjoysticks;
				}
				close(fd);
			}
		}
	}
	for ( i=0; i<SDL_TABLESIZE(joydev_pattern); ++i ) {
		done = 0;
		for ( j=0; (j < MAX_JOYSTICKS) && !done; ++j ) {
			sprintf(path, joydev_pattern[i], j);

			/* rcg06302000 replaced access(F_OK) call with stat().
			 * stat() will fail if the file doesn't exist, so it's
			 * equivalent behaviour.
			 */
			if ( stat(path, &sb) == 0 ) {
				/* Check to make sure it's not already in list.
				 * This happens when we see a stick via symlink.
				 */
				duplicate = 0;
				for (n=0; (n<numjoysticks) && !duplicate; ++n) {
					if ( sb.st_rdev == dev_nums[n] ) {
						duplicate = 1;
					}
				}
				if (duplicate) {
					continue;
				}

				fd = open(path, O_RDONLY, 0);
				if ( fd < 0 ) {
					continue;
				}
#ifdef USE_INPUT_EVENTS
#ifdef DEBUG_INPUT_EVENTS
				printf("Checking %s\n", path);
#endif
				if ( (i > 0) && ! EV_IsJoystick(fd) ) {
					close(fd);
					continue;
				}
#endif
				close(fd);

				/* We're fine, add this joystick */
				SDL_joylist[numjoysticks] = mystrdup(path);
				if ( SDL_joylist[numjoysticks] ) {
					dev_nums[numjoysticks] = sb.st_rdev;
					++numjoysticks;
				}
			} else {
				done = 1;
			}
		}
        /* This is a special case...
           If we're looking at the /dev/input event devices, and we found
           at least one, then we don't want to look at the input joystick
           devices, since they're built on top of devices that we've already
           seen, so we're done.
         */
        if ( i > 0 && j > 0 ) {
            done = 1;
        }
	}
	return(numjoysticks);
}

/* Function to get the device-dependent name of a joystick */
const char *SDL_SYS_JoystickName(int index)
{
	int fd;
	static char namebuf[128];
	char *name;

	name = NULL;
	fd = open(SDL_joylist[index], O_RDONLY, 0);
	if ( fd >= 0 ) {
		if ( 
#ifdef USE_INPUT_EVENTS
		     (ioctl(fd, EVIOCGNAME(sizeof(namebuf)), namebuf) <= 0) &&
#endif
		     (ioctl(fd, JSIOCGNAME(sizeof(namebuf)), namebuf) <= 0) ) {
			name = SDL_joylist[index];
		} else {
			name = namebuf;
		}
		close(fd);
	}
	return name;
}

#ifdef FANCY_HATS_AND_BALLS

static int allocate_hatdata(SDL_Joystick *joystick)
{
	int i;

	joystick->hwdata->hats = (struct hwdata_hat *)malloc(
		joystick->nhats * sizeof(struct hwdata_hat));
	if ( joystick->hwdata->hats == NULL ) {
		return(-1);
	}
	for ( i=0; i<joystick->nhats; ++i ) {
		joystick->hwdata->hats[i].axis[0] = 1;
		joystick->hwdata->hats[i].axis[1] = 1;
	}
	return(0);
}

static int allocate_balldata(SDL_Joystick *joystick)
{
	int i;

	joystick->hwdata->balls = (struct hwdata_ball *)malloc(
		joystick->nballs * sizeof(struct hwdata_ball));
	if ( joystick->hwdata->balls == NULL ) {
		return(-1);
	}
	for ( i=0; i<joystick->nballs; ++i ) {
		joystick->hwdata->balls[i].axis[0] = 0;
		joystick->hwdata->balls[i].axis[1] = 0;
	}
	return(0);
}

static SDL_bool ConfigJoystick(SDL_Joystick *joystick,
			const char *name, const char *config)
{
	char cfg_name[128];
	SDL_bool handled;

	if ( config == NULL ) {
		return(SDL_FALSE);
	}
	strcpy(cfg_name, "");
	if ( *config == '\'' ) {
		sscanf(config, "'%[^']s'", cfg_name);
		config += strlen(cfg_name)+2;
	} else {
		sscanf(config, "%s", cfg_name);
		config += strlen(cfg_name);
	}
	handled = SDL_FALSE;
	if ( strcmp(cfg_name, name) == 0 ) {
		/* Get the number of axes, hats and balls for this joystick */
		int joystick_axes = joystick->naxes;
		sscanf(config, "%d %d %d", 
			&joystick->naxes, &joystick->nhats, &joystick->nballs);

		/* Allocate the extra data for mapping them */
		if ( joystick->nhats > 0 ) {
			/* HACK: Analog hats map to only one axis */
			if (joystick_axes == (joystick->naxes+joystick->nhats)){
				joystick->hwdata->analog_hat = 1;
			} else {
				if ( allocate_hatdata(joystick) < 0 ) {
					joystick->nhats = 0;
				}
				joystick->hwdata->analog_hat = 0;
			}
		}
		if ( joystick->nballs > 0 ) {
			if ( allocate_balldata(joystick) < 0 ) {
				joystick->nballs = 0;
			}
		}
		handled = SDL_TRUE;
	}
	return(handled);
}

#ifdef USE_INPUT_EVENTS

static SDL_bool EV_ConfigJoystick(SDL_Joystick *joystick, int fd)
{
	int i;
	unsigned long keybit[40];
	unsigned long absbit[40];
	unsigned long relbit[40];

	/* See if this device uses the new unified event API */
	if ( (ioctl(fd, EVIOCGBIT(EV_KEY, sizeof(keybit)), keybit) >= 0) &&
	     (ioctl(fd, EVIOCGBIT(EV_ABS, sizeof(absbit)), absbit) >= 0) &&
	     (ioctl(fd, EVIOCGBIT(EV_REL, sizeof(relbit)), relbit) >= 0) ) {
		joystick->hwdata->is_hid = SDL_TRUE;

		/* Get the number of buttons, axes, and other thingamajigs */
		for ( i=BTN_JOYSTICK; i < KEY_MAX; ++i ) {
			if ( test_bit(i, keybit) ) {
#ifdef DEBUG_INPUT_EVENTS
				printf("Joystick has button: 0x%x\n", i);
#endif
				joystick->hwdata->key_map[i-BTN_MISC] =
						joystick->nbuttons;
				++joystick->nbuttons;
			}
		}
		for ( i=BTN_MISC; i < BTN_JOYSTICK; ++i ) {
			if ( test_bit(i, keybit) ) {
#ifdef DEBUG_INPUT_EVENTS
				printf("Joystick has button: 0x%x\n", i);
#endif
				joystick->hwdata->key_map[i-BTN_MISC] =
						joystick->nbuttons;
				++joystick->nbuttons;
			}
		}
		for ( i=0; i<ABS_MAX; ++i ) {
			/* Skip hats */
			if ( i == ABS_HAT0X ) {
				i = ABS_HAT3Y;
				continue;
			}
			if ( test_bit(i, absbit) ) {
				int values[5];

				ioctl(fd, EVIOCGABS(i), values);
#ifdef DEBUG_INPUT_EVENTS
				printf("Joystick has absolute axis: %x\n", i);
				printf("Values = { %d, %d, %d, %d, %d }\n",
					values[0], values[1],
					values[2], values[3], values[4]);
#endif /* DEBUG_INPUT_EVENTS */
				joystick->hwdata->abs_map[i] = joystick->naxes;
				if ( values[1] == values[2] ) {
				    joystick->hwdata->abs_correct[i].used = 0;
				} else {
				    joystick->hwdata->abs_correct[i].used = 1;
				    joystick->hwdata->abs_correct[i].coef[0] =
					(values[2] + values[1]) / 2 - values[4];
				    joystick->hwdata->abs_correct[i].coef[1] =
					(values[2] + values[1]) / 2 + values[4];
				    joystick->hwdata->abs_correct[i].coef[2] =
					(1 << 29) / ((values[2] - values[1]) / 2 - 2 * values[4]);
				}
				++joystick->naxes;
			}
		}
		for ( i=ABS_HAT0X; i <= ABS_HAT3Y; i += 2 ) {
			if ( test_bit(i, absbit) || test_bit(i+1, absbit) ) {
#ifdef DEBUG_INPUT_EVENTS
				printf("Joystick has hat %d\n",(i-ABS_HAT0X)/2);
#endif
				++joystick->nhats;
			}
		}
		if ( test_bit(REL_X, relbit) || test_bit(REL_Y, relbit) ) {
			++joystick->nballs;
		}

		/* Allocate data to keep track of these thingamajigs */
		if ( joystick->nhats > 0 ) {
			if ( allocate_hatdata(joystick) < 0 ) {
				joystick->nhats = 0;
			}
		}
		if ( joystick->nballs > 0 ) {
			if ( allocate_balldata(joystick) < 0 ) {
				joystick->nballs = 0;
			}
		}
	}
	return(joystick->hwdata->is_hid);
}

#endif /* USE_INPUT_EVENTS */

#endif /* FANCY_HATS_AND_BALLS */

/* 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)
{
#ifdef FANCY_HATS_AND_BALLS
	const char *name;
	int i;
#endif
	int fd;
	unsigned char n;

	/* Open the joystick and set the joystick file descriptor */
	fd = open(SDL_joylist[joystick->index], O_RDONLY, 0);
	if ( fd < 0 ) {
		SDL_SetError("Unable to open %s\n",
		             SDL_joylist[joystick->index]);
		return(-1);
	}
	joystick->hwdata = (struct joystick_hwdata *)
	                   malloc(sizeof(*joystick->hwdata));
	if ( joystick->hwdata == NULL ) {
		SDL_OutOfMemory();
		close(fd);
		return(-1);
	}
	memset(joystick->hwdata, 0, sizeof(*joystick->hwdata));
	joystick->hwdata->fd = fd;

	/* Set the joystick to non-blocking read mode */
	fcntl(fd, F_SETFL, O_NONBLOCK);

	/* Get the number of buttons and axes on the joystick */
#ifdef USE_INPUT_EVENTS
	if ( ! EV_ConfigJoystick(joystick, fd) )
#endif
	{
		if ( ioctl(fd, JSIOCGAXES, &n) < 0 ) {
			joystick->naxes = 2;
		} else {
			joystick->naxes = n;
		}
		if ( ioctl(fd, JSIOCGBUTTONS, &n) < 0 ) {
			joystick->nbuttons = 2;
		} else {
			joystick->nbuttons = n;
		}
#ifdef FANCY_HATS_AND_BALLS
		/* Check for special joystick support */
		name = SDL_SYS_JoystickName(joystick->index);
		for ( i=0; special_joysticks[i]; ++i ) {
			if (ConfigJoystick(joystick,name,special_joysticks[i])){
				break;
			}
		}
		if ( special_joysticks[i] == NULL ) {
			ConfigJoystick(joystick, name,
					getenv("SDL_LINUX_JOYSTICK"));
		}
#endif /* FANCY_HATS_AND_BALLS */
	}
	return(0);
}

static __inline__
void HandleHat(SDL_Joystick *stick, Uint8 hat, int axis, int value)
{
	struct hwdata_hat *the_hat;
	const Uint8 position_map[3][3] = {
		{ SDL_HAT_LEFTUP, SDL_HAT_UP, SDL_HAT_RIGHTUP },
		{ SDL_HAT_LEFT, SDL_HAT_CENTERED, SDL_HAT_RIGHT },
		{ SDL_HAT_LEFTDOWN, SDL_HAT_DOWN, SDL_HAT_RIGHTDOWN }
	};

	the_hat = &stick->hwdata->hats[hat];
	if ( value < 0 ) {
		value = 0;
	} else
	if ( value == 0 ) {
		value = 1;
	} else
	if ( value > 0 ) {
		value = 2;
	}
	if ( value != the_hat->axis[axis] ) {
		the_hat->axis[axis] = value;
		SDL_PrivateJoystickHat(stick, hat,
			position_map[the_hat->axis[1]][the_hat->axis[0]]);
	}
}

/* This was necessary for the Wingman Extreme Analog joystick */
static __inline__
void HandleAnalogHat(SDL_Joystick *stick, Uint8 hat, int value)
{
	const Uint8 position_map[] = {
		SDL_HAT_UP,
		SDL_HAT_RIGHT,
		SDL_HAT_DOWN,
		SDL_HAT_LEFT,
		SDL_HAT_CENTERED
	};
	SDL_PrivateJoystickHat(stick, hat, position_map[(value/16000)+2]);
}

static __inline__
void HandleBall(SDL_Joystick *stick, Uint8 ball, int axis, int value)
{
	stick->hwdata->balls[ball].axis[axis] += value;
}

/* 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.
 */
static __inline__ void JS_HandleEvents(SDL_Joystick *joystick)
{
	struct js_event events[32];
	int i, len;
	Uint8 other_axis;

	while ((len=read(joystick->hwdata->fd, events, (sizeof events))) > 0) {
		len /= sizeof(events[0]);
		for ( i=0; i<len; ++i ) {
			switch (events[i].type & ~JS_EVENT_INIT) {
			    case JS_EVENT_AXIS:
				if ( events[i].number < joystick->naxes ) {
					SDL_PrivateJoystickAxis(joystick,
				           events[i].number, events[i].value);
					break;
				}
				events[i].number -= joystick->naxes;
				if ( joystick->hwdata->analog_hat ) {
					other_axis = events[i].number;
					if ( other_axis < joystick->nhats ) {
						HandleAnalogHat(joystick, other_axis,
							events[i].value);
						break;
					}
				} else {
					other_axis = (events[i].number / 2);
					if ( other_axis < joystick->nhats ) {
						HandleHat(joystick, other_axis,
							events[i].number%2,
							events[i].value);
						break;
					}
				}
				events[i].number -= joystick->nhats*2;
				other_axis = (events[i].number / 2);
				if ( other_axis < joystick->nballs ) {
					HandleBall(joystick, other_axis,
						events[i].number%2,
						events[i].value);
					break;
				}
				break;
			    case JS_EVENT_BUTTON:
				SDL_PrivateJoystickButton(joystick,
				           events[i].number, events[i].value);
				break;
			    default:
				/* ?? */
				break;
			}
		}
	}
}
#ifdef USE_INPUT_EVENTS
static __inline__ int EV_AxisCorrect(SDL_Joystick *joystick, int which, int value)
{
	struct axis_correct *correct;

	correct = &joystick->hwdata->abs_correct[which];
	if ( correct->used ) {
		if ( value > correct->coef[0] ) {
			if ( value < correct->coef[1] ) {
				return 0;
			}
			value -= correct->coef[1];
		} else {
			value -= correct->coef[0];
		}
		value *= correct->coef[2];
		value >>= 14;
	}
	/* Clamp and return */
	if ( value < -32767 ) {
		value = -32767;
	} else
	if ( value > 32767 ) {
		value = 32767;
	}
	return value;
}

static __inline__ void EV_HandleEvents(SDL_Joystick *joystick)
{
	struct input_event events[32];
	int i, len;
	int code;

	while ((len=read(joystick->hwdata->fd, events, (sizeof events))) > 0) {
		len /= sizeof(events[0]);
		for ( i=0; i<len; ++i ) {
			code = events[i].code;
			switch (events[i].type) {
			    case EV_KEY:
				if ( code >= BTN_MISC ) {
					code -= BTN_MISC;
					SDL_PrivateJoystickButton(joystick,
				           joystick->hwdata->key_map[code],
					   events[i].value);
				}
				break;
			    case EV_ABS:
				switch (code) {
				    case ABS_HAT0X:
				    case ABS_HAT0Y:
				    case ABS_HAT1X:
				    case ABS_HAT1Y:
				    case ABS_HAT2X:
				    case ABS_HAT2Y:
				    case ABS_HAT3X:
				    case ABS_HAT3Y:
					code -= ABS_HAT0X;
					HandleHat(joystick, code/2, code%2,
							events[i].value);
					break;
				    default:
					events[i].value = EV_AxisCorrect(joystick, code, events[i].value);
					SDL_PrivateJoystickAxis(joystick,
				           joystick->hwdata->abs_map[code],
					   events[i].value);
					break;
				}
				break;
			    case EV_REL:
				switch (code) {
				    case REL_X:
				    case REL_Y:
					code -= REL_X;
					HandleBall(joystick, code/2, code%2,
							events[i].value);
					break;
				    default:
					break;
				}
				break;
			    default:
				break;
			}
		}
	}
}
#endif /* USE_INPUT_EVENTS */

void SDL_SYS_JoystickUpdate(SDL_Joystick *joystick)
{
	int i;
	
#ifdef USE_INPUT_EVENTS
	if ( joystick->hwdata->is_hid )
		EV_HandleEvents(joystick);
	else
#endif
		JS_HandleEvents(joystick);

	/* Deliver ball motion updates */
	for ( i=0; i<joystick->nballs; ++i ) {
		int xrel, yrel;

		xrel = joystick->hwdata->balls[i].axis[0];
		yrel = joystick->hwdata->balls[i].axis[1];
		if ( xrel || yrel ) {
			joystick->hwdata->balls[i].axis[0] = 0;
			joystick->hwdata->balls[i].axis[1] = 0;
			SDL_PrivateJoystickBall(joystick, (Uint8)i, xrel, yrel);
		}
	}
}

/* Function to close a joystick after use */
void SDL_SYS_JoystickClose(SDL_Joystick *joystick)
{
	if ( joystick->hwdata ) {
		close(joystick->hwdata->fd);
		if ( joystick->hwdata->hats ) {
			free(joystick->hwdata->hats);
		}
		if ( joystick->hwdata->balls ) {
			free(joystick->hwdata->balls);
		}
		free(joystick->hwdata);
		joystick->hwdata = NULL;
	}
}

/* Function to perform any system-specific joystick related cleanup */
void SDL_SYS_JoystickQuit(void)
{
	int i;

	for ( i=0; SDL_joylist[i]; ++i ) {
		free(SDL_joylist[i]);
	}
	SDL_joylist[0] = NULL;
}