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/**
 * @file wind.cpp
 * Helper functions for wind states
 */

#include "ekf.h"
#include <ekf_derivation/generated/compute_wind_init_and_cov_from_wind_speed_and_direction.h>

void Ekf::resetWindToExternalObservation(float wind_speed, float wind_direction, float wind_speed_accuracy,
		float wind_direction_accuracy)
{
	if (!_control_status.flags.in_air) {

		const float wind_speed_constrained = math::max(wind_speed, 0.0f);
		const float wind_direction_var = sq(wind_direction_accuracy);
		const float wind_speed_var = sq(wind_speed_accuracy);

		Vector2f wind;
		Vector2f wind_var;

		sym::ComputeWindInitAndCovFromWindSpeedAndDirection(wind_speed_constrained, wind_direction, wind_speed_var,
				wind_direction_var, &wind, &wind_var);

		ECL_INFO("reset wind states to external observation");
		_information_events.flags.reset_wind_to_ext_obs = true;
		_external_wind_init = true;

		resetWindTo(wind, wind_var);

	}
}

void Ekf::resetWindTo(const Vector2f &wind, const Vector2f &wind_var)
{
	_state.wind_vel = wind;

	if (PX4_ISFINITE(wind_var(0))) {
		P.uncorrelateCovarianceSetVariance<1>(State::wind_vel.idx,
						      math::min(sq(_params.initial_wind_uncertainty), wind_var(0)));
	}

	if (PX4_ISFINITE(wind_var(1))) {
		P.uncorrelateCovarianceSetVariance<1>(State::wind_vel.idx + 1,
						      math::min(sq(_params.initial_wind_uncertainty), wind_var(1)));
	}
}

void Ekf::resetWindCov()
{
	// start with a small initial uncertainty to improve the initial estimate
	P.uncorrelateCovarianceSetVariance<State::wind_vel.dof>(State::wind_vel.idx, sq(_params.initial_wind_uncertainty));
}

void Ekf::resetWindToZero()
{
	ECL_INFO("reset wind to zero");
	_state.wind_vel.setZero();
	resetWindCov();
}