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/**
 * @file followme.cpp
 *
 * Helper class to track and follow a given position
 *
 * @author Jimmy Johnson <catch22@fastmail.net>
 */

#pragma once

#include <controllib/blocks.hpp>
#include <controllib/block/BlockParam.hpp>
#include <lib/mathlib/math/Vector.hpp>
#include <lib/mathlib/math/Matrix.hpp>
#include "navigator_mode.h"
#include "mission_block.h"

class FollowTarget : public MissionBlock
{

public:
	FollowTarget(Navigator *navigator, const char *name);

	FollowTarget(const FollowTarget &) = delete;
	FollowTarget &operator=(const FollowTarget &) = delete;

	~FollowTarget();

	void on_inactive() override;
	void on_activation() override;
	void on_active() override;

private:

	static constexpr int TARGET_TIMEOUT_MS = 2500;
	static constexpr int TARGET_ACCEPTANCE_RADIUS_M = 5;
	static constexpr int INTERPOLATION_PNTS = 20;
	static constexpr float FF_K = .25F;
	static constexpr float OFFSET_M = 8;

	enum FollowTargetState {
		TRACK_POSITION,
		TRACK_VELOCITY,
		SET_WAIT_FOR_TARGET_POSITION,
		WAIT_FOR_TARGET_POSITION
	};

	enum {
		FOLLOW_FROM_RIGHT,
		FOLLOW_FROM_BEHIND,
		FOLLOW_FROM_FRONT,
		FOLLOW_FROM_LEFT
	};

	float _follow_position_matricies[4][9] = {
				 	 	 	 	 	 {1.0F,  -1.0F, 0.0F,
						 	 	 	  1.0F,   1.0F, 0.0F,
									  0.0F,   0.0F, 1.0F}, // follow right

									 {-1.0F,  0.0F, 0.0F,
						 	 	 	   0.0F, -1.0F, 0.0F,
									   0.0F,  0.0F, 1.0F}, // follow behind

									 {1.0F,   0.0F, 0.0F,
							 	 	  0.0F,   1.0F, 0.0F,
									  0.0F,   0.0F, 1.0F}, // follow front

									 {1.0F,   1.0F, 0.0F,
							 	 	 -1.0F,   1.0F, 0.0F,
									  0.0F,   0.0F, 1.0F}}; // follow left side


	Navigator *_navigator;
	control::BlockParamFloat	_param_min_alt;
	control::BlockParamFloat 	_param_tracking_dist;
	control::BlockParamInt 		_param_tracking_side;
	control::BlockParamFloat 	_param_tracking_resp;
	control::BlockParamFloat 	_param_yaw_auto_max;


	FollowTargetState _follow_target_state;
	int _follow_target_position;

	int _follow_target_sub;
	float _step_time_in_ms;
	float _follow_offset;

	uint64_t _target_updates;
	uint64_t _last_update_time;

	math::Vector<3> _current_vel;
	math::Vector<3> _step_vel;
	math::Vector<3> _est_target_vel;
	math::Vector<3> _target_distance;
	math::Vector<3> _target_position_offset;
	math::Vector<3> _target_position_delta;
	math::Vector<3> _filtered_target_position_delta;

	follow_target_s _current_target_motion;
	follow_target_s _previous_target_motion;
	float _yaw_rate;
	float _responsiveness;
	float _yaw_auto_max;
	float _yaw_angle;

	// Mavlink defined motion reporting capabilities

    enum {
        POS = 0,
        VEL = 1,
        ACCEL = 2,
        ATT_RATES = 3
    };

	math::Matrix<3,3> _rot_matrix;
	void track_target_position();
	void track_target_velocity();
	bool target_velocity_valid();
	bool target_position_valid();
	void reset_target_validity();
	void update_position_sp(bool velocity_valid, bool position_valid, float yaw_rate);
	void update_target_motion();
	void update_target_velocity();
};