/**

 * $Id$

 *

 * Linux joystick input device support

 *

 * Copyright (c) 2008 Nathan Keynes.

 *

 * This program 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 Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program 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.

 */

#ifndef _GNU_SOURCE

#define _GNU_SOURCE

#endif

#include <sys/types.h>

#include <sys/ioctl.h>

#include <errno.h>

#include <stdio.h>

#include <signal.h>

#include <string.h>

#include <stdlib.h>

#include <unistd.h>

#include <fcntl.h>

#include <dirent.h>

#include <ctype.h>

#include <linux/joystick.h>

#include <glib.h>

#include "lxdream.h"

#include "display.h"

#include "maple/maple.h"

#include "drivers/joy_linux.h"

#define INPUT_PATH "/dev/input"

typedef struct linux_joystick {

    struct input_driver driver;

    const gchar *filename;

    char name[128];

    int fd;

    int button_count, axis_count;

    GIOChannel *channel;

} *linux_joystick_t;

/* Linux joysticks return data in the range -32767 to 32767 - rescale this to 

 * -127 .. 127

 */

#define SCALE_PRESSURE(x) ((x)>>8)

static gboolean linux_joystick_callback( GIOChannel *source, GIOCondition condition, 

                                         gpointer data );

static int linux_joystick_scan();

static linux_joystick_t linux_joystick_new( const gchar *filename, int fd );

static uint16_t linux_joystick_resolve_keysym( input_driver_t dev, const gchar *str );

static gchar *linux_joystick_keysym_for_keycode( input_driver_t dev, uint16_t keycode );

static void linux_joystick_destroy( input_driver_t joy );

static gboolean linux_joystick_install_watch( const gchar *dir );

static void linux_joystick_uninstall_watch( void );

/**

 * Convert keysym to keycode. Keysyms are either Button%d or Axis%d[+-], with buttons

 * numbered 1 .. button_count, then axes from button_count+1 .. button_count + axis_count*2.

 * The first button is Button1. (no Button0)

 * The first axis is Axis1+, then Axis1-, Axis2+ and so forth.

 */

static uint16_t linux_joystick_resolve_keysym( input_driver_t dev, const gchar *str )

{

    linux_joystick_t joy = (linux_joystick_t)dev;

    if( strncasecmp( str, "Button", 6 ) == 0 ){

        unsigned long button = strtoul( str+6, NULL, 10 );

        if( button > joy->button_count ) {

            return 0;

        }

        return (uint16_t)button;

    } else if( strncasecmp( str, "Axis", 4 ) == 0 ) {

        char *endptr;

        unsigned long axis = strtoul( str+4, &endptr, 10 );

        if( axis > joy->axis_count || axis == 0 ) {

            return 0;

        }

        int keycode = ((axis - 1) << 1) + joy->button_count + 1;

        if( *endptr == '-' ) {

            return keycode + 1;

        } else {

            return keycode;

        }

    } else {

        return 0;

    }

}

static gchar *linux_joystick_keysym_for_keycode( input_driver_t dev, uint16_t keycode )

{

    linux_joystick_t joy = (linux_joystick_t)dev;

    if( keycode == 0 ) {

        return NULL;

    }

    if( keycode <= joy->button_count ) {

        return g_strdup_printf( "Button%d", keycode );

    }

    if( keycode <= joy->button_count + joy->axis_count*2 ) {

        int axis = keycode - joy->button_count - 1;

        if( (axis & 1) == 0 ) {

            return g_strdup_printf( "Axis%d+", (axis >> 1)+1 );

        } else {

            return g_strdup_printf( "Axis%d-", (axis >> 1)+1 );

        }

    }

    return NULL;

}

static void linux_joystick_destroy( input_driver_t dev )

{

    linux_joystick_t joy = (linux_joystick_t)dev;

    g_free( (gchar *)joy->filename );

    g_io_channel_shutdown(joy->channel, FALSE, NULL );

    g_io_channel_unref(joy->channel);

    g_free( joy );

}

/**

 * Callback from the GIOChannel whenever data is available, or an error/disconnect

 * occurs.

 *

 * On data, process all pending events and direct them to the input system.

 * On error, close the channel and delete the device.

 */

static gboolean linux_joystick_callback( GIOChannel *source, GIOCondition condition, 

                                         gpointer data )

{

    linux_joystick_t joy = (linux_joystick_t)data;

    if( condition & G_IO_HUP ) {

        INFO( "Joystick '%s' disconnected\n", joy->name );

        input_unregister_device((input_driver_t)joy);

        return FALSE;

    }

    if( condition & G_IO_IN ) {

        struct js_event event;

        while( read( joy->fd, &event, sizeof(event) ) == sizeof(event) ) {

            if( event.type == JS_EVENT_BUTTON ) {

                int keycode = event.number+1;

                if( event.value == 0 ) {

                    input_event_keyup( (input_driver_t)joy, keycode );

                } else {

                    input_event_keydown( (input_driver_t)joy, keycode, MAX_PRESSURE );

                }

            } else if( event.type == JS_EVENT_AXIS ) {

                int keycode = (event.number*2) + joy->button_count + 1;

                if( event.value == 0 ) {

                    input_event_keyup( (input_driver_t)joy, keycode );

                    input_event_keyup( (input_driver_t)joy, keycode+1 );

                } else if( event.value < 0 ) {

                    input_event_keyup( (input_driver_t)joy, keycode );

                    input_event_keydown( (input_driver_t)joy, keycode+1, SCALE_PRESSURE(-event.value) );

                } else {

                    input_event_keyup( (input_driver_t)joy, keycode+1 );

                    input_event_keydown( (input_driver_t)joy, keycode, SCALE_PRESSURE(event.value) );

                }

            }

        }

    }

    return TRUE;

}

/**

 * Create a new joystick device structure given filename and (open) file

 * descriptor. The joystick is automatically added to the watch list.

 * @return The new joystick, or NULL if an error occurred.

 */

static linux_joystick_t linux_joystick_new( const gchar *filename, int fd )

{

    linux_joystick_t joy = g_malloc0(sizeof(struct linux_joystick));

    joy->filename = filename;

    joy->fd = fd;

    joy->name[0] = '\0';

    joy->driver.resolve_keysym = linux_joystick_resolve_keysym;

    joy->driver.get_keysym_for_keycode = linux_joystick_keysym_for_keycode;

    joy->driver.destroy = linux_joystick_destroy;

    char *p = strrchr(filename, '/');

    if( p == NULL ) {

        joy->driver.id = filename;

    } else {

        joy->driver.id = p+1;

    }

    if( ioctl( fd, JSIOCGNAME(128), joy->name ) == -1 ||

            ioctl( fd, JSIOCGAXES, &joy->axis_count ) == -1 || 

            ioctl( fd, JSIOCGBUTTONS, &joy->button_count ) == -1 ) {

        ERROR( "Error reading joystick data from %s (%s)\n", filename, strerror(errno) );

        g_free(joy);

        return NULL;

    }

    joy->channel = g_io_channel_unix_new(fd);

    g_io_add_watch( joy->channel, G_IO_IN|G_IO_ERR|G_IO_HUP, linux_joystick_callback, joy );

    return joy;

}

static int linux_joystick_scan()

{

    int joysticks = 0;

    struct dirent *ent;

    DIR *dir = opendir(INPUT_PATH);

    if( dir == NULL ) {

        return 0;

    }

    while( (ent = readdir(dir)) != NULL ) {

        if( ent->d_name[0] == 'j' && ent->d_name[1] == 's' &&

                isdigit(ent->d_name[2]) && !input_has_device(ent->d_name) ) {

            gchar *name = g_strdup_printf( "%s/%s", INPUT_PATH, ent->d_name );

            int fd = open(name, O_RDONLY|O_NONBLOCK);

            if( fd == -1 ) {

                g_free( name );

            } else {

                linux_joystick_t joy = linux_joystick_new( name, fd );

                input_register_device( (input_driver_t)joy, (joy->axis_count*2) + joy->button_count );

                INFO( "Attached joystick %s named '%s', (%d buttons, %d axes)", 

                      joy->driver.id, joy->name, joy->button_count, joy->axis_count );

                joysticks++;

            }

        }

    }

    closedir(dir);

    return joysticks;

}

gboolean linux_joystick_init()

{

    if( !linux_joystick_install_watch(INPUT_PATH) ) {

        return FALSE;

    }

    linux_joystick_scan();

    return TRUE;

}

void linux_joystick_shutdown(void)

{

    linux_joystick_uninstall_watch();

}

/*************************** dnotify support **********************/

static volatile int need_input_rescan = 0;

static int watch_dir_fd;

static gboolean gtk_loop_check_input(gpointer data)

{

    if( need_input_rescan == 1 ) {

        need_input_rescan = 0;

        int js = linux_joystick_scan();

        if( js > 0 ) {

            maple_reattach_all();

        }

    }

    return need_input_rescan != 2;

}

static void dnotify_handler(int sig )

{

    need_input_rescan = 1;

}

static gboolean linux_joystick_install_watch( const gchar *dir )

{

    int fd = open( dir, O_RDONLY|O_NONBLOCK );

    if( fd == -1 ) {

        return FALSE;

    }

    signal( SIGRTMIN+1, dnotify_handler );

    fcntl(fd, F_SETSIG, SIGRTMIN + 1);

    if( fcntl(fd, F_NOTIFY, DN_CREATE|DN_MULTISHOT) == -1 ) {

        close(fd);

        return FALSE;

    }

    watch_dir_fd = fd;

    g_timeout_add( 500, gtk_loop_check_input, NULL );

    return TRUE;

}

static void linux_joystick_uninstall_watch(void)

{

    signal( SIGRTMIN+1, SIG_IGN );

    close( watch_dir_fd );

    need_input_rescan = 2;

}