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/**
 * @file gimbal.cpp
 * @author Lorenz Meier <lm@inf.ethz.ch>
 *
 * Driver to control a gimbal - relies on input via telemetry or RC
 * and output via the standardized control group #2 and a mixer.
 */

#include <nuttx/config.h>

#include <sys/types.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdbool.h>
#include <semaphore.h>
#include <string.h>
#include <fcntl.h>
#include <poll.h>
#include <errno.h>
#include <stdio.h>
#include <math.h>
#include <unistd.h>
#include <termios.h>

#include <nuttx/arch.h>
#include <nuttx/wqueue.h>
#include <nuttx/clock.h>

#include <systemlib/perf_counter.h>
#include <systemlib/err.h>

#include <drivers/drv_hrt.h>
#include <drivers/drv_range_finder.h>
#include <drivers/device/device.h>
#include <drivers/device/ringbuffer.h>

#include <uORB/uORB.h>
#include <uORB/topics/vehicle_command.h>
#include <uORB/topics/actuator_controls.h>
#include <uORB/topics/vehicle_attitude.h>

#include <board_config.h>
#include <mathlib/math/test/test.hpp>

/* Configuration Constants */

/* oddly, ERROR is not defined for c++ */
#ifdef ERROR
# undef ERROR
#endif
static const int ERROR = -1;

#ifndef CONFIG_SCHED_WORKQUEUE
# error This requires CONFIG_SCHED_WORKQUEUE.
#endif

#define GIMBAL_DEVICE_PATH	"/dev/gimbal"

#define GIMBAL_UPDATE_INTERVAL (50 * 1000)

#define GIMBALIOCATTCOMPENSATE	1

class Gimbal : public device::CDev
{
public:
	Gimbal();
	virtual ~Gimbal();

	virtual int 			init();

	virtual ssize_t			read(struct file *filp, char *buffer, size_t buflen);
	virtual int			ioctl(struct file *filp, int cmd, unsigned long arg);

	/**
	* Diagnostics - print some basic information about the driver.
	*/
	void				print_info();

protected:
	virtual int			probe();

private:
	float				_min_distance;
	float				_max_distance;
	work_s				_work;
	int				_vehicle_command_sub;
	int				_att_sub;

	bool				_attitude_compensation;
	bool				_initialized;

	orb_advert_t			_actuator_controls_2_topic;

	perf_counter_t			_sample_perf;
	perf_counter_t			_comms_errors;
	perf_counter_t			_buffer_overflows;

	/**
	* Initialise the automatic measurement state machine and start it.
	*
	* @note This function is called at open and error time.  It might make sense
	*       to make it more aggressive about resetting the bus in case of errors.
	*/
	void				start();

	/**
	* Stop the automatic measurement state machine.
	*/
	void				stop();

	/**
	* Perform a poll cycle; collect from the previous measurement
	* and start a new one.
	*/
	void				cycle();

	/**
	* Static trampoline from the workq context; because we don't have a
	* generic workq wrapper yet.
	*
	* @param arg		Instance pointer for the driver that is polling.
	*/
	static void			cycle_trampoline(void *arg);


};

/*
 * Driver 'main' command.
 */
extern "C" __EXPORT int gimbal_main(int argc, char *argv[]);

Gimbal::Gimbal() :
	CDev("Gimbal", GIMBAL_DEVICE_PATH),
	_vehicle_command_sub(-1),
	_att_sub(-1),
	_attitude_compensation(false),
	_initialized(false),
	_actuator_controls_2_topic(-1),
	_sample_perf(perf_alloc(PC_ELAPSED, "gimbal_read")),
	_comms_errors(perf_alloc(PC_COUNT, "gimbal_comms_errors")),
	_buffer_overflows(perf_alloc(PC_COUNT, "gimbal_buffer_overflows"))
{
	// disable debug() calls
	_debug_enabled = false;

	// work_cancel in the dtor will explode if we don't do this...
	memset(&_work, 0, sizeof(_work));
}

Gimbal::~Gimbal()
{
	/* make sure we are truly inactive */
	stop();

	::close(_actuator_controls_2_topic);
	::close(_vehicle_command_sub);
}

int
Gimbal::init()
{
	int ret = ERROR;

	/* do regular cdev init */
	if (CDev::init() != OK) {
		goto out;
	}

	start();
	ret = OK;

out:
	return ret;
}

int
Gimbal::probe()
{
	return OK;
}

int
Gimbal::ioctl(struct file *filp, int cmd, unsigned long arg)
{
	switch (cmd) {

	case GIMBALIOCATTCOMPENSATE:
		_attitude_compensation = (arg != 0);
		return OK;

	default:
		/* give it to the superclass */
		return CDev::ioctl(filp, cmd, arg);
	}
}

ssize_t
Gimbal::read(struct file *filp, char *buffer, size_t buflen)
{
	return 0;
}

void
Gimbal::start()
{

	/* schedule a cycle to start things */
	work_queue(LPWORK, &_work, (worker_t)&Gimbal::cycle_trampoline, this, 1);
}

void
Gimbal::stop()
{
	work_cancel(LPWORK, &_work);
}

void
Gimbal::cycle_trampoline(void *arg)
{
	Gimbal *dev = static_cast<Gimbal *>(arg);

	dev->cycle();
}

void
Gimbal::cycle()
{

	if (!_initialized) {
		/* get a subscription handle on the vehicle command topic */
		_vehicle_command_sub = orb_subscribe(ORB_ID(vehicle_command));

		/* get a publication handle on actuator output topic */
		struct actuator_controls_s zero_report;
		memset(&zero_report, 0, sizeof(zero_report));
		zero_report.timestamp = hrt_absolute_time();
		_actuator_controls_2_topic = orb_advertise(ORB_ID(actuator_controls_2), &zero_report);

		if (_actuator_controls_2_topic < 0) {
			warnx("advert err");
		}

		_initialized = true;
	}

	bool	updated = false;

	perf_begin(_sample_perf);

	float roll = 0.0f;
	float pitch = 0.0f;


	if (_attitude_compensation) {
		if (_att_sub < 0) {
			_att_sub = orb_subscribe(ORB_ID(vehicle_attitude));
		}

		vehicle_attitude_s att;

		orb_copy(ORB_ID(vehicle_attitude), _att_sub, &att);

		roll = -att.roll;
		pitch = -att.pitch;

		updated = true;

	}

	struct vehicle_command_s cmd;

	bool cmd_updated;

	orb_check(_vehicle_command_sub, &cmd_updated);

	if (cmd_updated) {

		orb_copy(ORB_ID(vehicle_command), _vehicle_command_sub, &cmd);

		//debug("cmd: %d, param1: %8.4f param2: %8.4f", (double)cmd.command, (double)cmd.param1, (double)cmd.param2);

		if (cmd.command == VEHICLE_CMD_DO_MOUNT_CONTROL && equal(cmd.param7, VEHICLE_MOUNT_MODE_MAVLINK_TARGETING)) {

			/* Convert to range -1 ... 1, which corresponds to -180deg ... 180deg */
			roll += 1.0f / M_PI_F * M_DEG_TO_RAD_F * cmd.param1;
			pitch += 1.0f / M_PI_F * M_DEG_TO_RAD_F * cmd.param2;

			updated = true;

		}

		// XXX change this to the real quaternion command
		if (cmd.command == VEHICLE_CMD_DO_MOUNT_CONTROL_QUAT && equal(cmd.param7, VEHICLE_MOUNT_MODE_MAVLINK_TARGETING)) {

			/* Convert to range -1 ... 1, which corresponds to -180deg ... 180deg */
			roll += 1.0f / M_PI_F * M_DEG_TO_RAD_F * cmd.param1;
			pitch += 1.0f / M_PI_F * M_DEG_TO_RAD_F * cmd.param2;

			updated = true;

		}
	}

	if (updated) {

		struct actuator_controls_s controls;

		/* fill in the final control values */
		controls.timestamp = hrt_absolute_time();
		controls.control[0] = roll;
		controls.control[1] = pitch;

		/* publish it */
		orb_publish(ORB_ID(actuator_controls_2), _actuator_controls_2_topic, &controls);

	}

	/* notify anyone waiting for data */
	poll_notify(POLLIN);

	perf_end(_sample_perf);

	/* schedule a fresh cycle call when the measurement is done */
	work_queue(LPWORK,
		   &_work,
		   (worker_t)&Gimbal::cycle_trampoline,
		   this,
		   USEC2TICK(GIMBAL_UPDATE_INTERVAL));
}

void
Gimbal::print_info()
{
	perf_print_counter(_sample_perf);
	perf_print_counter(_comms_errors);
	perf_print_counter(_buffer_overflows);
}

/**
 * Local functions in support of the shell command.
 */
namespace gimbal
{

/* oddly, ERROR is not defined for c++ */
#ifdef ERROR
# undef ERROR
#endif
const int ERROR = -1;

Gimbal	*g_dev;

void	start();
void	stop();
void	test();
void	reset();
void	info();

/**
 * Start the driver.
 */
void
start()
{
	if (g_dev != nullptr) {
		errx(1, "already started");
	}

	/* create the driver */
	g_dev = new Gimbal();

	if (g_dev == nullptr) {
		goto fail;
	}

	if (OK != g_dev->init()) {
		goto fail;
	}

	exit(0);

fail:

	if (g_dev != nullptr) {
		delete g_dev;
		g_dev = nullptr;
	}

	errx(1, "driver start failed");
}

/**
 * Stop the driver
 */
void stop()
{
	if (g_dev != nullptr) {
		delete g_dev;
		g_dev = nullptr;

	} else {
		errx(1, "driver not running");
	}

	exit(0);
}

/**
 * Perform some basic functional tests on the driver;
 * make sure we can collect data from the sensor in polled
 * and automatic modes.
 */
void
test()
{
	int fd = open(GIMBAL_DEVICE_PATH, O_RDONLY);

	if (ioctl(fd, GIMBALIOCATTCOMPENSATE, 1) < 0) {
		err(1, "failed enabling compensation");
	}

	errx(0, "PASS");
}

/**
 * Reset the driver.
 */
void
reset()
{
	int fd = open(GIMBAL_DEVICE_PATH, O_RDONLY);

	if (fd < 0) {
		err(1, "failed ");
	}

	// if (ioctl(fd, GIMBALIOCATTCOMPENSATE, 1) < 0) {
	// 	err(1, "failed enabling compensation");
	// }

	exit(0);
}

/**
 * Print a little info about the driver.
 */
void
info()
{
	if (g_dev == nullptr) {
		errx(1, "driver not running");
	}

	printf("state @ %p\n", g_dev);
	g_dev->print_info();

	exit(0);
}

} // namespace

int
gimbal_main(int argc, char *argv[])
{
	/*
	 * Start/load the driver.
	 */
	if (!strcmp(argv[1], "start")) {
		gimbal::start();
	}

	/*
	 * Stop the driver
	 */
	if (!strcmp(argv[1], "stop")) {
		gimbal::stop();
	}

	/*
	 * Test the driver/device.
	 */
	if (!strcmp(argv[1], "test")) {
		gimbal::test();
	}

	/*
	 * Reset the driver.
	 */
	if (!strcmp(argv[1], "reset")) {
		gimbal::reset();
	}

	/*
	 * Print driver information.
	 */
	if (!strcmp(argv[1], "info") || !strcmp(argv[1], "status")) {
		gimbal::info();
	}

	errx(1, "unrecognized command, try 'start', 'test', 'reset' or 'info'");
}