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/**
 * @file MulticopterLandDetector.h
 * Land detection implementation for multicopters.
 *
 * @author Johan Jansen <jnsn.johan@gmail.com>
 * @author Morten Lysgaard <morten@lysgaard.no>
 * @author Julian Oes <julian@oes.ch>
 */

#pragma once

#include "LandDetector.h"

#include <systemlib/param/param.h>
#include <uORB/topics/vehicle_local_position.h>
#include <uORB/topics/vehicle_local_position_setpoint.h>
#include <uORB/topics/vehicle_attitude.h>
#include <uORB/topics/actuator_controls.h>
#include <uORB/topics/actuator_controls.h>
#include <uORB/topics/battery_status.h>
#include <uORB/topics/parameter_update.h>
#include <uORB/topics/sensor_bias.h>
#include <uORB/topics/vehicle_attitude.h>
#include <uORB/topics/vehicle_control_mode.h>
#include <uORB/topics/vehicle_local_position.h>

namespace land_detector
{

class MulticopterLandDetector : public LandDetector
{
public:
	MulticopterLandDetector();

protected:
	void _initialize_topics() override;
	void _update_params() override;
	void _update_topics() override;

	bool _get_landed_state() override;
	bool _get_ground_contact_state() override;
	bool _get_maybe_landed_state() override;
	bool _get_freefall_state() override;

	float _get_max_altitude() override;
private:

	/** Time in us that landing conditions have to hold before triggering a land. */
	static constexpr uint64_t LAND_DETECTOR_TRIGGER_TIME_US = 300000;

	/** Time in us that almost landing conditions have to hold before triggering almost landed . */
	static constexpr uint64_t MAYBE_LAND_DETECTOR_TRIGGER_TIME_US = 250000;

	/** Time in us that ground contact condition have to hold before triggering contact ground */
	static constexpr uint64_t GROUND_CONTACT_TRIGGER_TIME_US = 350000;

	/** Time interval in us in which wider acceptance thresholds are used after landed. */
	static constexpr uint64_t LAND_DETECTOR_LAND_PHASE_TIME_US = 2000000;

	/**
	* @brief Handles for interesting parameters
	**/
	struct {
		param_t maxClimbRate;
		param_t maxVelocity;
		param_t maxRotation;
		param_t minThrottle;
		param_t hoverThrottle;
		param_t throttleRange;
		param_t minManThrottle;
		param_t freefall_acc_threshold;
		param_t freefall_trigger_time;
		param_t altitude_max;
		param_t landSpeed;
	} _paramHandle{};

	struct {
		float maxClimbRate;
		float maxVelocity;
		float maxRotation_rad_s;
		float minThrottle;
		float hoverThrottle;
		float throttleRange;
		float minManThrottle;
		float freefall_acc_threshold;
		float freefall_trigger_time;
		float altitude_max;
		float landSpeed;
	} _params{};

	int _vehicleLocalPositionSub{-1};
	int _vehicleLocalPositionSetpointSub{-1};
	int _actuatorsSub{-1};
	int _attitudeSub{-1};
	int _sensor_bias_sub{-1};
	int _vehicle_control_mode_sub{-1};
	int _battery_sub{-1};

	vehicle_local_position_s				_vehicleLocalPosition {};
	vehicle_local_position_setpoint_s	_vehicleLocalPositionSetpoint {};
	actuator_controls_s					_actuators {};
	vehicle_attitude_s					_vehicleAttitude {};
	sensor_bias_s					_sensors {};
	vehicle_control_mode_s				_control_mode {};
	battery_status_s						_battery {};

	uint64_t _min_trust_start{0};		///< timestamp when minimum trust was applied first
	uint64_t _landed_time{0};

	/* get control mode dependent pilot throttle threshold with which we should quit landed state and take off */
	float _get_takeoff_throttle();
	bool _has_altitude_lock();
	bool _has_position_lock();
	bool _has_minimal_thrust();
	bool _has_low_thrust();
	bool _is_climb_rate_enabled();
};


} // namespace land_detector
