/*************************************************************************/
/*  joystick_linux.cpp                                                   */
/*************************************************************************/
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/* Copyright (c) 2007-2016 Juan Linietsky, Ariel Manzur.                 */
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//author: Andreas Haas <hondres,  liugam3@gmail.com>
#ifdef JOYDEV_ENABLED

#include "joystick_linux.h"
#include "print_string.h"

#include <libevdev/libevdev.h>
#include <libudev.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <cstring>

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

joystick_linux::Joystick::Joystick() {
	fd = -1;
	dpad = 0;
	dev = NULL;
	devpath = "";
}

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 != NULL && strstr(devnode, ignore_str) == NULL) {
			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();
				const char* action = udev_device_get_action(dev);
				const char* devnode = udev_device_get_devnode(dev);

				if (strstr(devnode, ignore_str) == NULL) {

					if (strcmp(action, "add") == 0)
						open_joystick(devnode);

					else if (strcmp(action, "remove") == 0)
						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) {

		libevdev_free(joy.dev);
		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];
	libevdev* dev = joy->dev;

	int num_buttons = 0;
	int num_axes = 0;

	for (int i = BTN_JOYSTICK; i < KEY_MAX; ++i) {

		if (libevdev_has_event_code(dev, EV_KEY, i)) {

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

		if (libevdev_has_event_code(dev, EV_KEY, i)) {

			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 (libevdev_has_event_code(dev, EV_ABS, i)) {

			joy->abs_map[i] = num_axes++;
		}
	}
}

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) {

		int rc = libevdev_new_from_fd(fd, &joysticks[joy_num].dev);
		if (rc < 0) {

			fprintf(stderr, "Failed to init libevdev (%s)\n", strerror(-rc));
			return;
		}

		libevdev *dev = joysticks[joy_num].dev;

		//check if the device supports basic gamepad events, prevents certain keyboards from
		//being detected as joysticks
		if (libevdev_has_event_type(dev, EV_ABS) && libevdev_has_event_type(dev, EV_KEY) &&
				(libevdev_has_event_code(dev, EV_KEY, BTN_A) || libevdev_has_event_code(dev, EV_KEY, BTN_THUMBL) || libevdev_has_event_code(dev, EV_KEY, BTN_TOP))) {

			char uid[128];
			String name = libevdev_get_name(dev);
			uint16_t bus = __bswap_16(libevdev_get_id_bustype(dev));
			uint16_t vendor = __bswap_16(libevdev_get_id_vendor(dev));
			uint16_t product = __bswap_16(libevdev_get_id_product(dev));
			uint16_t version = __bswap_16(libevdev_get_id_version(dev));

			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", bus, 0);
			if (vendor && product && 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);

			}
		}
		else {
			//device is not a gamepad, clean up
			libevdev_free(dev);
			close(fd);
		}
	}
}

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 ev;
		Joystick* joy = &joysticks[i];
		libevdev* dev = joy->dev;
		int rc = 1;

		rc = libevdev_next_event(dev, LIBEVDEV_READ_FLAG_NORMAL, &ev);

		if (rc < 0 && rc != -EAGAIN) {
			continue;
		}

		while (rc == LIBEVDEV_READ_STATUS_SYNC || rc == LIBEVDEV_READ_STATUS_SUCCESS) {

			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) {
						InputDefault::JoyAxis value = axis_correct(libevdev_get_abs_info(dev, ev.code), ev.value);
						joy->curr_axis[joy->abs_map[ev.code]] = value;
					}
					break;
				}
				break;
			}
			rc = libevdev_next_event(dev, LIBEVDEV_READ_FLAG_NORMAL, &ev);
		}
		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