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/**
 * @file FlightTask.hpp
 *
 * Abstract base class for different advanced flight tasks like orbit, follow me, ...
 *
 * @author Matthias Grob <maetugr@gmail.com>
 */

#pragma once

#include <px4_module_params.h>
#include <drivers/drv_hrt.h>
#include <matrix/matrix/math.hpp>
#include <uORB/Subscription.hpp>
#include <uORB/topics/vehicle_local_position.h>
#include <uORB/topics/vehicle_local_position_setpoint.h>
#include <uORB/topics/vehicle_command.h>
#include <uORB/topics/vehicle_constraints.h>
#include <uORB/topics/vehicle_attitude.h>
#include "SubscriptionArray.hpp"

class FlightTask : public ModuleParams
{
public:
	FlightTask() :
		ModuleParams(nullptr)
	{
		_resetSetpoints();
		_constraints = empty_constraints;
	}

	virtual ~FlightTask() = default;

	/**
	 * Initialize the uORB subscriptions using an array
	 * @return true on success, false on error
	 */
	virtual bool initializeSubscriptions(SubscriptionArray &subscription_array);

	/**
	 * Call once on the event where you switch to the task
	 * @return true on success, false on error
	 */
	virtual bool activate();

	/**
	 * To be called to adopt parameters from an arrived vehicle command
	 * @return true if accepted, false if declined
	 */
	virtual bool applyCommandParameters(const vehicle_command_s &command) { return true; };

	/**
	 * Call before activate() or update()
	 * to initialize time and input data
	 * @return true on success, false on error
	 */
	virtual bool updateInitialize();

	/**
	 * To be called regularly in the control loop cycle to execute the task
	 * @return true on success, false on error
	 */
	virtual bool update() = 0;

	/**
	 * Get the output data
	 */
	const vehicle_local_position_setpoint_s getPositionSetpoint();

	/**
	 * Get vehicle constraints.
	 * The constraints can vary with task.
	 * @return constraints
	 */
	const vehicle_constraints_s getConstraints() {return _constraints;};

	/**
	 * Empty setpoint.
	 * All setpoints are set to NAN.
	 */
	static const vehicle_local_position_setpoint_s empty_setpoint;

	/**
	 * Empty constraints.
	 * All constraints are set to NAN.
	 */
	static const vehicle_constraints_s empty_constraints;

	/**
	 * Call this whenever a parameter update notification is received (parameter_update uORB message)
	 */
	void handleParameterUpdate()
	{
		updateParams();
	}

protected:

	uORB::Subscription<vehicle_local_position_s> *_sub_vehicle_local_position{nullptr};
	uORB::Subscription<vehicle_attitude_s> *_sub_attitude{nullptr};
	uint8_t _heading_reset_counter{0}; /**< estimator heading reset */

	/**
	 * Reset all setpoints to NAN
	 */
	void _resetSetpoints();

	/*
	 * Check and update local position
	 */
	bool _evaluateVehicleLocalPosition();

	/**
	 * Set constraints to default values
	 */
	virtual void  _setDefaultConstraints();

	/* Time abstraction */
	static constexpr uint64_t _timeout = 500000; /**< maximal time in us before a loop or data times out */
	float _time = 0; /**< passed time in seconds since the task was activated */
	float _deltatime = 0; /**< passed time in seconds since the task was last updated */
	hrt_abstime _time_stamp_activate = 0; /**< time stamp when task was activated */
	hrt_abstime _time_stamp_current = 0; /**< time stamp at the beginning of the current task update */
	hrt_abstime _time_stamp_last = 0; /**< time stamp when task was last updated */

	/* Current vehicle state */
	matrix::Vector3f _position; /**< current vehicle position */
	matrix::Vector3f _velocity; /**< current vehicle velocity */
	float _yaw = 0.f; /**< current vehicle yaw heading */
	float _dist_to_bottom = 0.0f; /**< current height above ground level */

	/**
	 * Setpoints which the position controller has to execute.
	 * Setpoints that are set to NAN are not controlled. Not all setpoints can be set at the same time.
	 * If more than one type of setpoint is set, then order of control is a as follow: position, velocity,
	 * acceleration, thrust. The exception is _position_setpoint together with _velocity_setpoint, where the
	 * _velocity_setpoint is used as feedforward.
	 * _acceleration_setpoint is currently not supported.
	 */
	matrix::Vector3f _position_setpoint;
	matrix::Vector3f _velocity_setpoint;
	matrix::Vector3f _acceleration_setpoint;
	matrix::Vector3f _thrust_setpoint;
	float _yaw_setpoint;
	float _yawspeed_setpoint;

	/**
	 * Vehicle constraints.
	 * The constraints can vary with tasks.
	 */
	vehicle_constraints_s _constraints;

	DEFINE_PARAMETERS_CUSTOM_PARENT(ModuleParams,
					(ParamFloat<px4::params::MPC_XY_VEL_MAX>) MPC_XY_VEL_MAX,
					(ParamFloat<px4::params::MPC_Z_VEL_MAX_DN>) MPC_Z_VEL_MAX_DN,
					(ParamFloat<px4::params::MPC_Z_VEL_MAX_UP>) MPC_Z_VEL_MAX_UP,
					(ParamFloat<px4::params::MPC_TILTMAX_AIR>) MPC_TILTMAX_AIR
				       )
};