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/**
 * @file hover_thrust_estimator.cpp
 *
 * @author Mathieu Bresciani 	<brescianimathieu@gmail.com>
 */

#include "MulticopterHoverThrustEstimator.hpp"

#include <mathlib/mathlib.h>

MulticopterHoverThrustEstimator::MulticopterHoverThrustEstimator() :
	ModuleParams(nullptr),
	WorkItem(MODULE_NAME, px4::wq_configurations::lp_default)
{
	updateParams();
	reset();
}

MulticopterHoverThrustEstimator::~MulticopterHoverThrustEstimator()
{
	perf_free(_cycle_perf);
}

bool MulticopterHoverThrustEstimator::init()
{
	if (!_vehicle_local_position_setpoint_sub.registerCallback()) {
		PX4_ERR("vehicle_local_position_setpoint callback registration failed!");
		return false;
	}

	return true;
}

void MulticopterHoverThrustEstimator::reset()
{
	_hover_thrust_ekf.setHoverThrust(_param_mpc_thr_hover.get());
	_hover_thrust_ekf.setHoverThrustStdDev(_param_hte_ht_err_init.get());
	_hover_thrust_ekf.resetAccelNoise();
}

void MulticopterHoverThrustEstimator::updateParams()
{
	const float ht_err_init_prev = _param_hte_ht_err_init.get();
	ModuleParams::updateParams();

	_hover_thrust_ekf.setProcessNoiseStdDev(_param_hte_ht_noise.get());

	if (fabsf(_param_hte_ht_err_init.get() - ht_err_init_prev) > FLT_EPSILON) {
		_hover_thrust_ekf.setHoverThrustStdDev(_param_hte_ht_err_init.get());
	}

	_hover_thrust_ekf.setAccelInnovGate(_param_hte_acc_gate.get());
}

void MulticopterHoverThrustEstimator::Run()
{
	if (should_exit()) {
		_vehicle_local_position_setpoint_sub.unregisterCallback();
		exit_and_cleanup();
		return;
	}

	// check for parameter updates
	if (_parameter_update_sub.updated()) {
		// clear update
		parameter_update_s pupdate;
		_parameter_update_sub.copy(&pupdate);

		// update parameters from storage
		updateParams();
	}

	perf_begin(_cycle_perf);

	vehicle_land_detected_s vehicle_land_detected;
	vehicle_status_s vehicle_status;
	vehicle_local_position_s local_pos;

	if (_vehicle_land_detected_sub.update(&vehicle_land_detected)) {
		_landed = vehicle_land_detected.landed;
	}

	if (_vehicle_status_sub.update(&vehicle_status)) {
		_armed = (vehicle_status.arming_state == vehicle_status_s::ARMING_STATE_ARMED);
	}

	if (_vehicle_local_pos_sub.update(&local_pos)) {
		// This is only necessary because the landed
		// flag of the land detector does not guarantee that
		// the vehicle does not touch the ground anymore
		// TODO: improve the landed flag
		_in_air = local_pos.dist_bottom > 1.f;
	}

	ZeroOrderHoverThrustEkf::status status{};

	if (_armed && !_landed && _in_air) {
		vehicle_local_position_setpoint_s local_pos_sp;

		if (_vehicle_local_position_setpoint_sub.update(&local_pos_sp)) {

			const hrt_abstime now = hrt_absolute_time();
			const float dt = math::constrain((now - _timestamp_last) / 1e6f, 0.002f, 0.2f);

			_hover_thrust_ekf.predict(dt);

			if (PX4_ISFINITE(local_pos.az) && PX4_ISFINITE(local_pos_sp.thrust[2])) {
				// Inform the hover thrust estimator about the measured vertical
				// acceleration (positive acceleration is up) and the current thrust (positive thrust is up)
				_hover_thrust_ekf.fuseAccZ(-local_pos.az, -local_pos_sp.thrust[2], status);
			}
		}

	} else {
		if (!_armed) {
			reset();
		}

		status.hover_thrust = _hover_thrust_ekf.getHoverThrustEstimate();
		status.hover_thrust_var = _hover_thrust_ekf.getHoverThrustEstimateVar();
		status.accel_noise_var = _hover_thrust_ekf.getAccelNoiseVar();
		status.innov = NAN;
		status.innov_var = NAN;
		status.innov_test_ratio = NAN;
	}

	publishStatus(status);

	perf_end(_cycle_perf);
}

void MulticopterHoverThrustEstimator::publishStatus(ZeroOrderHoverThrustEkf::status &status)
{
	hover_thrust_estimate_s status_msg{};
	status_msg.hover_thrust = status.hover_thrust;
	status_msg.hover_thrust_var = status.hover_thrust_var;
	status_msg.accel_innov = status.innov;
	status_msg.accel_innov_var = status.innov_var;
	status_msg.accel_innov_test_ratio = status.innov_test_ratio;
	status_msg.accel_noise_var = status.accel_noise_var;
	status_msg.timestamp = hrt_absolute_time();
	_hover_thrust_ekf_pub.publish(status_msg);
}

int MulticopterHoverThrustEstimator::task_spawn(int argc, char *argv[])
{
	MulticopterHoverThrustEstimator *instance = new MulticopterHoverThrustEstimator();

	if (instance) {
		_object.store(instance);
		_task_id = task_id_is_work_queue;

		if (instance->init()) {
			return PX4_OK;
		}

	} else {
		PX4_ERR("alloc failed");
	}

	delete instance;
	_object.store(nullptr);
	_task_id = -1;

	return PX4_ERROR;
}

int MulticopterHoverThrustEstimator::custom_command(int argc, char *argv[])
{
	return print_usage("unknown command");
}

int MulticopterHoverThrustEstimator::print_status()
{
	perf_print_counter(_cycle_perf);

	return 0;
}

int MulticopterHoverThrustEstimator::print_usage(const char *reason)
{
	if (reason) {
		PX4_WARN("%s\n", reason);
	}

	PRINT_MODULE_DESCRIPTION(
		R"DESCR_STR(
### Description

)DESCR_STR");

	PRINT_MODULE_USAGE_NAME("mc_hover_thrust_estimator", "estimator");
	PRINT_MODULE_USAGE_COMMAND("start");
	PRINT_MODULE_USAGE_DEFAULT_COMMANDS();

	return 0;
}

extern "C" __EXPORT int mc_hover_thrust_estimator_main(int argc, char *argv[])
{
	return MulticopterHoverThrustEstimator::main(argc, argv);
}