/*************************************************************************/
/*  joystick_linux.cpp                                                   */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                    http://www.godotengine.org                         */
/*************************************************************************/
/* Copyright (c) 2007-2016 Juan Linietsky, Ariel Manzur.                 */
/*                                                                       */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the       */
/* "Software"), to deal in the Software without restriction, including   */
/* without limitation the rights to use, copy, modify, merge, publish,   */
/* distribute, sublicense, and/or sell copies of the Software, and to    */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions:                                             */
/*                                                                       */
/* The above copyright notice and this permission notice shall be        */
/* included in all copies or substantial portions of the Software.       */
/*                                                                       */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
/*************************************************************************/

//author: Andreas Haas <hondres,  liugam3@gmail.com>
#ifdef JOYDEV_ENABLED

#include "joystick_linux.h"

#include <linux/input.h>
#include <libudev.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>

#define test_bit(nr, addr)  (((1UL << ((nr) % (sizeof(long) * 8))) & ((addr)[(nr) / (sizeof(long) * 8)])) != 0)
#define NBITS(x) ((((x)-1)/(sizeof(long) * 8))+1)

static const char* ignore_str = "/dev/input/js";

joystick_linux::Joystick::Joystick() {
	fd = -1;
	dpad = 0;
	devpath = "";
	for (int i = 0; i < MAX_ABS; i++) {
		abs_info[i] = NULL;
	}
}

joystick_linux::Joystick::~Joystick() {

	for (int i = 0; i < MAX_ABS; i++) {
		if (abs_info[i]) {
			memdelete(abs_info[i]);
		}
	}
}

void joystick_linux::Joystick::reset() {
	dpad        = 0;
	fd          = -1;

	InputDefault::JoyAxis jx;
	jx.min = -1;
	jx.value = 0.0f;
	for (int i=0; i < MAX_ABS; i++) {
		abs_map[i] = -1;
		curr_axis[i] = jx;
	}
}

joystick_linux::joystick_linux(InputDefault *in)
{
	exit_udev = false;
	input = in;
	joy_mutex = Mutex::create();
	joy_thread = Thread::create(joy_thread_func, this);
}

joystick_linux::~joystick_linux() {
	exit_udev = true;
	Thread::wait_to_finish(joy_thread);
	close_joystick();
}

void joystick_linux::joy_thread_func(void *p_user) {

	if (p_user) {
		joystick_linux* joy = (joystick_linux*) p_user;
		joy->run_joystick_thread();
	}
	return;
}

void joystick_linux::run_joystick_thread() {

	udev *_udev = udev_new();
	ERR_FAIL_COND(!_udev);
	enumerate_joysticks(_udev);
	monitor_joysticks(_udev);
	udev_unref(_udev);
}

void joystick_linux::enumerate_joysticks(udev *p_udev) {

	udev_enumerate *enumerate;
	udev_list_entry *devices, *dev_list_entry;
	udev_device *dev;

	enumerate = udev_enumerate_new(p_udev);
	udev_enumerate_add_match_subsystem(enumerate,"input");
	udev_enumerate_add_match_property(enumerate, "ID_INPUT_JOYSTICK", "1");

	udev_enumerate_scan_devices(enumerate);
	devices = udev_enumerate_get_list_entry(enumerate);
	udev_list_entry_foreach(dev_list_entry, devices) {

		const char* path = udev_list_entry_get_name(dev_list_entry);
		dev = udev_device_new_from_syspath(p_udev, path);
		const char* devnode = udev_device_get_devnode(dev);

		if (devnode) {

			String devnode_str = devnode;
			if (devnode_str.find(ignore_str) == -1) {
				joy_mutex->lock();
				open_joystick(devnode);
				joy_mutex->unlock();
			}
		}
		udev_device_unref(dev);
	}
	udev_enumerate_unref(enumerate);
}

void joystick_linux::monitor_joysticks(udev *p_udev) {

	udev_device *dev = NULL;
	udev_monitor *mon = udev_monitor_new_from_netlink(p_udev, "udev");
	udev_monitor_filter_add_match_subsystem_devtype(mon, "input", NULL);
	udev_monitor_enable_receiving(mon);
	int fd = udev_monitor_get_fd(mon);

	while (!exit_udev) {

		fd_set fds;
		struct timeval tv;
		int ret;

		FD_ZERO(&fds);
		FD_SET(fd, &fds);
		tv.tv_sec = 0;
		tv.tv_usec = 0;

		ret = select(fd+1, &fds, NULL, NULL, &tv);

		/* Check if our file descriptor has received data. */
		if (ret > 0 && FD_ISSET(fd, &fds)) {
			/* Make the call to receive the device.
			   select() ensured that this will not block. */
			dev = udev_monitor_receive_device(mon);

			if (dev && udev_device_get_devnode(dev) != 0) {

				joy_mutex->lock();
				String action = udev_device_get_action(dev);
				const char* devnode = udev_device_get_devnode(dev);
				if (devnode) {

					String devnode_str = devnode;
					if (devnode_str.find(ignore_str) == -1) {

						if (action == "add")
							open_joystick(devnode);
						else if (String(action) == "remove")
							close_joystick(get_joy_from_path(devnode));
					}
				}

				udev_device_unref(dev);
				joy_mutex->unlock();
			}
		}
		usleep(50000);
	}
	//printf("exit udev\n");
	udev_monitor_unref(mon);
}

int joystick_linux::get_free_joy_slot() const {

	for (int i = 0; i < JOYSTICKS_MAX; i++) {

		if (joysticks[i].fd == -1) return i;
	}
	return -1;
}

int joystick_linux::get_joy_from_path(String p_path) const {

	for (int i = 0; i < JOYSTICKS_MAX; i++) {

		if (joysticks[i].devpath == p_path) {
			return i;
		}
	}
	return -2;
}

void joystick_linux::close_joystick(int p_id) {
	if (p_id == -1) {
		for (int i=0; i<JOYSTICKS_MAX; i++) {

			close_joystick(i);
		};
		return;
	}
	else if (p_id < 0) return;

	Joystick &joy = joysticks[p_id];

	if (joy.fd != -1) {

		close(joy.fd);
		joy.fd = -1;
		input->joy_connection_changed(p_id, false, "");
	};
};

static String _hex_str(uint8_t p_byte) {

	static const char* dict = "0123456789abcdef";
	char ret[3];
	ret[2] = 0;

	ret[0] = dict[p_byte>>4];
	ret[1] = dict[p_byte & 0xF];

	return ret;
};

void joystick_linux::setup_joystick_properties(int p_id) {

	Joystick* joy = &joysticks[p_id];

	unsigned long keybit[NBITS(KEY_MAX)] = { 0 };
	unsigned long absbit[NBITS(ABS_MAX)] = { 0 };

	int num_buttons = 0;
	int num_axes = 0;

	if ((ioctl(joy->fd, EVIOCGBIT(EV_KEY, sizeof(keybit)), keybit) < 0) ||
	    (ioctl(joy->fd, EVIOCGBIT(EV_ABS, sizeof(absbit)), absbit) < 0)) {
		return;
	}
	for (int i = BTN_JOYSTICK; i < KEY_MAX; ++i) {

		if (test_bit(i, keybit)) {

			joy->key_map[i] = num_buttons++;
		}
	}
	for (int i = BTN_MISC; i < BTN_JOYSTICK; ++i) {

		if (test_bit(i, keybit)) {

			joy->key_map[i] = num_buttons++;
		}
	}
	for (int i = 0; i < ABS_MISC; ++i) {
		/* Skip hats */
		if (i == ABS_HAT0X) {
			i = ABS_HAT3Y;
			continue;
		}
		if (test_bit(i, absbit)) {

			joy->abs_map[i] = num_axes++;
			joy->abs_info[i] = memnew(input_absinfo);
			if (ioctl(joy->fd, EVIOCGABS(i), joy->abs_info[i]) < 0) {
				memdelete(joy->abs_info[i]);
				joy->abs_info[i] = NULL;
			}
		}
	}
}


void joystick_linux::open_joystick(const char *p_path) {

	int joy_num = get_free_joy_slot();
	int fd = open(p_path, O_RDONLY | O_NONBLOCK);
	if (fd != -1 && joy_num != -1) {

		unsigned long evbit[NBITS(EV_MAX)] = { 0 };
		unsigned long keybit[NBITS(KEY_MAX)] = { 0 };
		unsigned long absbit[NBITS(ABS_MAX)] = { 0 };

		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;
		}

		//check if the device supports basic gamepad events, prevents certain keyboards from
		//being detected as joysticks
		if (!(test_bit(EV_KEY, evbit) && test_bit(EV_ABS, evbit) &&
		    ((test_bit(ABS_X, absbit) || test_bit(ABS_Y, absbit)) ||
		     (test_bit(BTN_A, keybit) || test_bit(BTN_THUMBL, keybit))))) {
			close(fd);
			return;
		}

		char uid[128];
		char namebuf[128];
		String name = "";
		input_id inpid;
		if (ioctl(fd, EVIOCGNAME(sizeof(namebuf)), namebuf) >= 0) {
			name = namebuf;
		}

		if (ioctl(fd, EVIOCGID, &inpid) < 0) {
			close(fd);
			return;
		}

		joysticks[joy_num].reset();

		Joystick &joy = joysticks[joy_num];
		joy.fd = fd;
		joy.devpath = String(p_path);
		setup_joystick_properties(joy_num);
		sprintf(uid, "%04x%04x", __bswap_16(inpid.bustype), 0);
		if (inpid.vendor && inpid.product && inpid.version) {

			uint16_t vendor = __bswap_16(inpid.vendor);
			uint16_t product = __bswap_16(inpid.product);
			uint16_t version = __bswap_16(inpid.version);

			sprintf(uid + String(uid).length(), "%04x%04x%04x%04x%04x%04x", vendor,0,product,0,version,0);
			input->joy_connection_changed(joy_num, true, name, uid);
		}
		else {
			String uidname = uid;
			int uidlen = MIN(name.length(), 11);
			for (int i=0; i<uidlen; i++) {

				uidname = uidname + _hex_str(name[i]);
			}
			uidname += "00";
			input->joy_connection_changed(joy_num, true, name, uidname);
		}
	}
}

InputDefault::JoyAxis joystick_linux::axis_correct(const input_absinfo *p_abs, int p_value) const {

	int min = p_abs->minimum;
	int max = p_abs->maximum;
	InputDefault::JoyAxis jx;

	if (min < 0) {
		jx.min = -1;
		if (p_value < 0) {
			jx.value = (float) -p_value / min;
		}
		jx.value = (float) p_value / max;
	}
	if (min == 0) {
		jx.min = 0;
		jx.value = 0.0f + (float) p_value / max;
	}
	return jx;
}

uint32_t joystick_linux::process_joysticks(uint32_t p_event_id) {

	if (joy_mutex->try_lock() != OK) {
		return p_event_id;
	}
	for (int i=0; i<JOYSTICKS_MAX; i++) {

		if (joysticks[i].fd == -1) continue;

		input_event events[32];
		Joystick* joy = &joysticks[i];

		int len;

		while ((len = read(joy->fd, events, (sizeof events))) > 0) {
			len /= sizeof(events[0]);
			for (int j = 0; j < len; j++) {

				input_event &ev = events[j];
				switch (ev.type) {
				case EV_KEY:
					p_event_id = input->joy_button(p_event_id, i, joy->key_map[ev.code], ev.value);
					break;

				case EV_ABS:

					switch (ev.code) {
					case ABS_HAT0X:
						if (ev.value != 0) {
							if (ev.value < 0) joy->dpad |= InputDefault::HAT_MASK_LEFT;
							else              joy->dpad |= InputDefault::HAT_MASK_RIGHT;
						}
						else joy->dpad &= ~(InputDefault::HAT_MASK_LEFT | InputDefault::HAT_MASK_RIGHT);

						p_event_id = input->joy_hat(p_event_id, i, joy->dpad);
						break;

					case ABS_HAT0Y:
						if (ev.value != 0) {
							if (ev.value < 0) joy->dpad |= InputDefault::HAT_MASK_UP;
							else              joy->dpad |= InputDefault::HAT_MASK_DOWN;
						}
						else joy->dpad &= ~(InputDefault::HAT_MASK_UP | InputDefault::HAT_MASK_DOWN);

						p_event_id = input->joy_hat(p_event_id, i, joy->dpad);
						break;

					default:
						if (joy->abs_map[ev.code] != -1 && joy->abs_info[ev.code]) {
							InputDefault::JoyAxis value = axis_correct(joy->abs_info[ev.code], ev.value);
							joy->curr_axis[joy->abs_map[ev.code]] = value;
						}
						break;
					}
					break;
				}
			}
		}
		for (int j = 0; j < MAX_ABS; j++) {
			int index = joy->abs_map[j];
			if (index != -1) {
				p_event_id = input->joy_axis(p_event_id, i, index, joy->curr_axis[index]);
			}
		}
	}
	joy_mutex->unlock();
	return p_event_id;
}
#endif