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/**
 * @file FlightTaskOrbit.hpp
 *
 * Flight task for orbiting in a circle around a target position
 *
 * @author Matthias Grob <maetugr@gmail.com>
 */

#pragma once

#include "FlightTaskManualAltitudeSmoothVel.hpp"
#include <uORB/Publication.hpp>
#include <uORB/topics/orbit_status.h>
#include "StraightLine.hpp"
#include <lib/slew_rate/SlewRateYaw.hpp>

class FlightTaskOrbit : public FlightTaskManualAltitudeSmoothVel
{
public:
	FlightTaskOrbit();
	virtual ~FlightTaskOrbit() = default;

	bool applyCommandParameters(const vehicle_command_s &command) override;
	bool activate(const vehicle_local_position_setpoint_s &last_setpoint) override;
	bool update() override;

	/**
	 * Check the feasibility of orbit parameters with respect to
	 * centripetal acceleration a = v^2 / r
	 * @param r desired radius
	 * @param v desired velocity
	 * @param a maximal allowed acceleration
	 * @return true on success, false if value not accepted
	 */
	bool checkAcceleration(float r, float v, float a);

protected:
	/**
	 * Send out telemetry information for the log and MAVLink.
	 * @return true on success, false on error
	 */
	bool sendTelemetry();

	/**
	 * Change the radius of the circle.
	 * @param r desired new radius
	 * @return true on success, false if value not accepted
	 */
	bool setRadius(const float r);

	/**
	 * Change the velocity of the vehicle on the circle.
	 * @param v desired new velocity
	 * @return true on success, false if value not accepted
	 */
	bool setVelocity(const float v);

private:
	/** generates setpoints to smoothly reach the closest point on the circle when starting from far away */
	void generate_circle_approach_setpoints(const matrix::Vector2f &center_to_position);
	/** generates xy setpoints to make the vehicle orbit */
	void generate_circle_setpoints(const matrix::Vector2f &center_to_position);
	/** generates yaw setpoints to control the vehicle's heading */
	void generate_circle_yaw_setpoints(const matrix::Vector2f &center_to_position);

	float _r = 0.f; /**< radius with which to orbit the target */
	float _v = 0.f; /**< clockwise tangential velocity for orbiting in m/s */
	matrix::Vector2f _center; /**< local frame coordinates of the center point */

	bool _in_circle_approach = false;
	StraightLine _circle_approach_line;

	// TODO: create/use parameters for limits
	const float _radius_min = 1.f;
	const float _radius_max = 100.f;
	const float _velocity_max = 10.f;
	const float _acceleration_max = 2.f;

	/** yaw behaviour during the orbit flight according to MAVLink's ORBIT_YAW_BEHAVIOUR enum */
	int _yaw_behaviour = orbit_status_s::ORBIT_YAW_BEHAVIOUR_HOLD_FRONT_TO_CIRCLE_CENTER;
	float _initial_heading = 0.f; /**< the heading of the drone when the orbit command was issued */
	SlewRateYaw<float> _slew_rate_yaw;

	uORB::Publication<orbit_status_s> _orbit_status_pub{ORB_ID(orbit_status)};

	DEFINE_PARAMETERS(
		(ParamFloat<px4::params::MPC_XY_CRUISE>) _param_mpc_xy_cruise, /**< cruise speed for circle approach */
		(ParamFloat<px4::params::MPC_YAWRAUTO_MAX>) _param_mpc_yawrauto_max
	)
};