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/**
 * @file fake_height_control.cpp
 * Control functions for ekf fake height fusion
 */

#include "ekf.h"

void Ekf::controlFakeHgtFusion()
{
	auto &aid_src = _aid_src_fake_hgt;

	// If we aren't doing any aiding, fake position measurements at the last known vertical position to constrain drift
	const bool fake_hgt_data_ready = !isVerticalAidingActive()
					 && isTimedOut(aid_src.time_last_fuse, (uint64_t)2e5); // Fuse fake height at a limited rate

	if (fake_hgt_data_ready) {

		const float obs_var = sq(_params.pos_noaid_noise);
		const float innov_gate = 3.f;

		updateVerticalPositionAidSrcStatus(_time_delayed_us, _last_known_pos(2), obs_var, innov_gate, aid_src);


		const bool continuing_conditions_passing = !isVerticalAidingActive();
		const bool starting_conditions_passing = continuing_conditions_passing
				&& _vertical_velocity_deadreckon_time_exceeded
				&& _vertical_position_deadreckon_time_exceeded;

		if (_control_status.flags.fake_hgt) {
			if (continuing_conditions_passing) {

				// always protect against extreme values that could result in a NaN
				if (aid_src.test_ratio < sq(100.0f / innov_gate)) {
					fuseVerticalPosition(aid_src);
				}

				const bool is_fusion_failing = isTimedOut(aid_src.time_last_fuse, (uint64_t)4e5);

				if (is_fusion_failing) {
					resetFakeHgtFusion();
				}

			} else {
				stopFakeHgtFusion();
			}

		} else {
			if (starting_conditions_passing) {
				ECL_INFO("start fake height fusion");
				_control_status.flags.fake_hgt = true;
				resetFakeHgtFusion();
			}
		}

	} else if (_control_status.flags.fake_hgt && isVerticalAidingActive()) {
		stopFakeHgtFusion();
	}
}

void Ekf::resetFakeHgtFusion()
{
	ECL_INFO("reset fake height fusion");
	_last_known_pos(2) = _state.pos(2);

	resetVerticalVelocityToZero();
	resetHeightToLastKnown();

	_aid_src_fake_hgt.time_last_fuse = _time_delayed_us;
}

void Ekf::resetHeightToLastKnown()
{
	_information_events.flags.reset_pos_to_last_known = true;
	ECL_INFO("reset height to last known (%.3f)", (double)_last_known_pos(2));
	resetVerticalPositionTo(_last_known_pos(2), sq(_params.pos_noaid_noise));
}

void Ekf::stopFakeHgtFusion()
{
	if (_control_status.flags.fake_hgt) {
		ECL_INFO("stop fake height fusion");
		_control_status.flags.fake_hgt = false;

		resetEstimatorAidStatus(_aid_src_fake_hgt);
	}
}