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  /**
   * @file FlightTaskAuto.cpp
   */
  
  #include "FlightTaskAuto.hpp"
  #include <mathlib/mathlib.h>
  #include <float.h>
  
  using namespace matrix;
  
  static constexpr float SIGMA_NORM	= 0.001f;
  
  FlightTaskAuto::FlightTaskAuto() :
  	_obstacle_avoidance(this)
  {
  
  }
  
  bool FlightTaskAuto::activate(const vehicle_local_position_setpoint_s &last_setpoint)
  {
  	bool ret = FlightTask::activate(last_setpoint);
  	_position_setpoint = _position;
  	_velocity_setpoint = _velocity;
  	_yaw_setpoint = _yaw_sp_prev = _yaw;
  	_yawspeed_setpoint = 0.0f;
  	_setDefaultConstraints();
  	return ret;
  }
  
  bool FlightTaskAuto::updateInitialize()
  {
  	bool ret = FlightTask::updateInitialize();
  
  	_sub_home_position.update();
  	_sub_vehicle_status.update();
  	_sub_triplet_setpoint.update();
  
  	// require valid reference and valid target
  	ret = ret && _evaluateGlobalReference() && _evaluateTriplets();
  	// require valid position
  	ret = ret && PX4_ISFINITE(_position(0))
  	      && PX4_ISFINITE(_position(1))
  	      && PX4_ISFINITE(_position(2))
  	      && PX4_ISFINITE(_velocity(0))
  	      && PX4_ISFINITE(_velocity(1))
  	      && PX4_ISFINITE(_velocity(2));
  
  	return ret;
  }
  
  bool FlightTaskAuto::updateFinalize()
  {
  	// All the auto FlightTasks have to comply with defined maximum yaw rate
  	// If the FlightTask generates a yaw or a yawrate setpoint that exceeds this value
  	// it will see its setpoint constrained here
  	_limitYawRate();
  	_constraints.want_takeoff = _checkTakeoff();
  	return true;
  }
  
  void FlightTaskAuto::_limitYawRate()
  {
  	const float yawrate_max = math::radians(_param_mpc_yawrauto_max.get());
  
  	_yaw_sp_aligned = true;
  
  	if (PX4_ISFINITE(_yaw_setpoint) && PX4_ISFINITE(_yaw_sp_prev)) {
  		// Limit the rate of change of the yaw setpoint
  		const float dyaw_desired = matrix::wrap_pi(_yaw_setpoint - _yaw_sp_prev);
  		const float dyaw_max = yawrate_max * _deltatime;
  		const float dyaw = math::constrain(dyaw_desired, -dyaw_max, dyaw_max);
  		const float yaw_setpoint_sat = matrix::wrap_pi(_yaw_sp_prev + dyaw);
  
  		// The yaw setpoint is aligned when it is within tolerance
  		_yaw_sp_aligned = fabsf(matrix::wrap_pi(_yaw_setpoint - yaw_setpoint_sat)) < math::radians(_param_mis_yaw_err.get());
  
  		_yaw_setpoint = yaw_setpoint_sat;
  		_yaw_sp_prev = _yaw_setpoint;
  
  		if (!PX4_ISFINITE(_yawspeed_setpoint) && (_deltatime > FLT_EPSILON)) {
  			// Create a feedforward
  			_yawspeed_setpoint = dyaw / _deltatime;
  		}
  	}
  
  	if (PX4_ISFINITE(_yawspeed_setpoint)) {
  		// The yaw setpoint is aligned when its rate is not saturated
  		_yaw_sp_aligned = _yaw_sp_aligned && (fabsf(_yawspeed_setpoint) < yawrate_max);
  
  		_yawspeed_setpoint = math::constrain(_yawspeed_setpoint, -yawrate_max, yawrate_max);
  	}
  }
  
  bool FlightTaskAuto::_evaluateTriplets()
  {
  	// TODO: fix the issues mentioned below
  	// We add here some conditions that are only required because:
  	// 1. navigator continuously sends triplet during mission due to yaw setpoint. This
  	// should be removed in the navigator and only updates if the current setpoint actually has changed.
  	//
  	// 2. navigator should be responsible to send always three valid setpoints. If there is only one setpoint,
  	// then previous will be set to current vehicle position and next will be set equal to setpoint.
  	//
  	// 3. navigator originally only supports gps guided maneuvers. However, it now also supports some flow-specific features
  	// such as land and takeoff. The navigator should use for auto takeoff/land with flow the position in xy at the moment the
  	// takeoff/land was initiated. Until then we do this kind of logic here.
  
  	// Check if triplet is valid. There must be at least a valid altitude.
  
  	if (!_sub_triplet_setpoint.get().current.valid || !PX4_ISFINITE(_sub_triplet_setpoint.get().current.alt)) {
  		// Best we can do is to just set all waypoints to current state
  		_prev_prev_wp = _triplet_prev_wp = _triplet_target = _triplet_next_wp = _position;
  		_type = WaypointType::loiter;
  		_yaw_setpoint = _yaw;
  		_yawspeed_setpoint = NAN;
  		_target_acceptance_radius = _sub_triplet_setpoint.get().current.acceptance_radius;
  		_updateInternalWaypoints();
  		return true;
  	}
  
  	_type = (WaypointType)_sub_triplet_setpoint.get().current.type;
  
  	// Always update cruise speed since that can change without waypoint changes.
  	_mc_cruise_speed = _sub_triplet_setpoint.get().current.cruising_speed;
  
  	if (!PX4_ISFINITE(_mc_cruise_speed) || (_mc_cruise_speed < 0.0f)) {
  		// If no speed is planned use the default cruise speed as limit
  		_mc_cruise_speed = _constraints.speed_xy;
  	}
  
  	// Ensure planned cruise speed is below the maximum such that the smooth trajectory doesn't get capped
  	_mc_cruise_speed = math::min(_mc_cruise_speed, _param_mpc_xy_vel_max.get());
  
  	// Temporary target variable where we save the local reprojection of the latest navigator current triplet.
  	Vector3f tmp_target;
  
  	if (!PX4_ISFINITE(_sub_triplet_setpoint.get().current.lat)
  	    || !PX4_ISFINITE(_sub_triplet_setpoint.get().current.lon)) {
  		// No position provided in xy. Lock position
  		if (!PX4_ISFINITE(_lock_position_xy(0))) {
  			tmp_target(0) = _lock_position_xy(0) = _position(0);
  			tmp_target(1) = _lock_position_xy(1) = _position(1);
  
  		} else {
  			tmp_target(0) = _lock_position_xy(0);
  			tmp_target(1) = _lock_position_xy(1);
  		}
  
  	} else {
  		// reset locked position if current lon and lat are valid
  		_lock_position_xy.setAll(NAN);
  
  		// Convert from global to local frame.
  		map_projection_project(&_reference_position,
  				       _sub_triplet_setpoint.get().current.lat, _sub_triplet_setpoint.get().current.lon, &tmp_target(0), &tmp_target(1));
  	}
  
  	tmp_target(2) = -(_sub_triplet_setpoint.get().current.alt - _reference_altitude);
  
  	// Check if anything has changed. We do that by comparing the temporary target
  	// to the internal _triplet_target.
  	// TODO This is a hack and it would be much better if the navigator only sends out a waypoints once they have changed.
  
  	bool triplet_update = true;
  	const bool prev_next_validity_changed = (_prev_was_valid != _sub_triplet_setpoint.get().previous.valid)
  						|| (_next_was_valid != _sub_triplet_setpoint.get().next.valid);
  
  	if (PX4_ISFINITE(_triplet_target(0))
  	    && PX4_ISFINITE(_triplet_target(1))
  	    && PX4_ISFINITE(_triplet_target(2))
  	    && fabsf(_triplet_target(0) - tmp_target(0)) < 0.001f
  	    && fabsf(_triplet_target(1) - tmp_target(1)) < 0.001f
  	    && fabsf(_triplet_target(2) - tmp_target(2)) < 0.001f
  	    && !prev_next_validity_changed) {
  		// Nothing has changed: just keep old waypoints.
  		triplet_update = false;
  
  	} else {
  		_triplet_target = tmp_target;
  		_target_acceptance_radius = _sub_triplet_setpoint.get().current.acceptance_radius;
  
  		if (!PX4_ISFINITE(_triplet_target(0)) || !PX4_ISFINITE(_triplet_target(1))) {
  			// Horizontal target is not finite.
  			_triplet_target(0) = _position(0);
  			_triplet_target(1) = _position(1);
  		}
  
  		if (!PX4_ISFINITE(_triplet_target(2))) {
  			_triplet_target(2) = _position(2);
  		}
  
  		// If _triplet_target has updated, update also _triplet_prev_wp and _triplet_next_wp.
  		_prev_prev_wp = _triplet_prev_wp;
  
  		if (_isFinite(_sub_triplet_setpoint.get().previous) && _sub_triplet_setpoint.get().previous.valid) {
  			map_projection_project(&_reference_position, _sub_triplet_setpoint.get().previous.lat,
  					       _sub_triplet_setpoint.get().previous.lon, &_triplet_prev_wp(0), &_triplet_prev_wp(1));
  			_triplet_prev_wp(2) = -(_sub_triplet_setpoint.get().previous.alt - _reference_altitude);
  
  		} else {
  			_triplet_prev_wp = _position;
  		}
  
  		_prev_was_valid = _sub_triplet_setpoint.get().previous.valid;
  
  		if (_type == WaypointType::loiter) {
  			_triplet_next_wp = _triplet_target;
  
  		} else if (_isFinite(_sub_triplet_setpoint.get().next) && _sub_triplet_setpoint.get().next.valid) {
  			map_projection_project(&_reference_position, _sub_triplet_setpoint.get().next.lat,
  					       _sub_triplet_setpoint.get().next.lon, &_triplet_next_wp(0), &_triplet_next_wp(1));
  			_triplet_next_wp(2) = -(_sub_triplet_setpoint.get().next.alt - _reference_altitude);
  
  		} else {
  			_triplet_next_wp = _triplet_target;
  		}
  
  		_next_was_valid = _sub_triplet_setpoint.get().next.valid;
  	}
  
  	if (_ext_yaw_handler != nullptr) {
  		// activation/deactivation of weather vane is based on parameter WV_EN and setting of navigator (allow_weather_vane)
  		(_param_wv_en.get() && !_sub_triplet_setpoint.get().current.disable_weather_vane) ?	_ext_yaw_handler->activate() :
  		_ext_yaw_handler->deactivate();
  	}
  
  	// Calculate the current vehicle state and check if it has updated.
  	State previous_state = _current_state;
  	_current_state = _getCurrentState();
  
  	if (triplet_update || (_current_state != previous_state) || _current_state == State::offtrack) {
  		_updateInternalWaypoints();
  		_mission_gear = _sub_triplet_setpoint.get().current.landing_gear;
  		_yaw_lock = false;
  	}
  
  	if (_param_com_obs_avoid.get()
  	    && _sub_vehicle_status.get().vehicle_type == vehicle_status_s::VEHICLE_TYPE_ROTARY_WING) {
  		_obstacle_avoidance.updateAvoidanceDesiredWaypoints(_triplet_target, _yaw_setpoint, _yawspeed_setpoint,
  				_triplet_next_wp,
  				_sub_triplet_setpoint.get().next.yaw,
  				_sub_triplet_setpoint.get().next.yawspeed_valid ? _sub_triplet_setpoint.get().next.yawspeed : (float)NAN,
  				_ext_yaw_handler != nullptr && _ext_yaw_handler->is_active(), _sub_triplet_setpoint.get().current.type);
  		_obstacle_avoidance.checkAvoidanceProgress(_position, _triplet_prev_wp, _target_acceptance_radius, _closest_pt);
  	}
  
  	// set heading
  	if (_ext_yaw_handler != nullptr && _ext_yaw_handler->is_active()) {
  		_yaw_setpoint = _yaw;
  		// use the yawrate setpoint from WV only if not moving lateral (velocity setpoint below half of _param_mpc_xy_cruise)
  		// otherwise, keep heading constant (as output from WV is not according to wind in this case)
  		bool vehicle_is_moving_lateral = _velocity_setpoint.xy().longerThan(_param_mpc_xy_cruise.get() / 2.0f);
  
  		if (vehicle_is_moving_lateral) {
  			_yawspeed_setpoint = 0.0f;
  
  		} else {
  			_yawspeed_setpoint = _ext_yaw_handler->get_weathervane_yawrate();
  		}
  
  
  
  	} else if (_type == WaypointType::follow_target && _sub_triplet_setpoint.get().current.yawspeed_valid) {
  		_yawspeed_setpoint = _sub_triplet_setpoint.get().current.yawspeed;
  		_yaw_setpoint = NAN;
  
  	} else {
  		if ((_type != WaypointType::takeoff || _sub_triplet_setpoint.get().current.disable_weather_vane)
  		    && _sub_triplet_setpoint.get().current.yaw_valid) {
  			// Use the yaw computed in Navigator except during takeoff because
  			// Navigator is not handling the yaw reset properly.
  			// But: use if from Navigator during takeoff if disable_weather_vane is true,
  			// because we're then aligning to the transition waypoint.
  			// TODO: fix in navigator
  			_yaw_setpoint = _sub_triplet_setpoint.get().current.yaw;
  
  		} else {
  			_set_heading_from_mode();
  		}
  
  		_yawspeed_setpoint = NAN;
  	}
  
  	return true;
  }
  
  void FlightTaskAuto::_set_heading_from_mode()
  {
  
  	Vector2f v; // Vector that points towards desired location
  
  	switch (_param_mpc_yaw_mode.get()) {
  
  	case 0: // Heading points towards the current waypoint.
  	case 4: // Same as 0 but yaw first and then go
  		v = Vector2f(_target) - Vector2f(_position);
  		break;
  
  	case 1: // Heading points towards home.
  		if (_sub_home_position.get().valid_lpos) {
  			v = Vector2f(&_sub_home_position.get().x) - Vector2f(_position);
  		}
  
  		break;
  
  	case 2: // Heading point away from home.
  		if (_sub_home_position.get().valid_lpos) {
  			v = Vector2f(_position) - Vector2f(&_sub_home_position.get().x);
  		}
  
  		break;
  
  	case 3: // Along trajectory.
  		// The heading depends on the kind of setpoint generation. This needs to be implemented
  		// in the subclasses where the velocity setpoints are generated.
  		v.setAll(NAN);
  		break;
  	}
  
  	if (PX4_ISFINITE(v.length())) {
  		// We only adjust yaw if vehicle is outside of acceptance radius. Once we enter acceptance
  		// radius, lock yaw to current yaw.
  		// This prevents excessive yawing.
  		if (!_yaw_lock) {
  			if (v.length() < _target_acceptance_radius) {
  				_yaw_setpoint = _yaw;
  				_yaw_lock = true;
  
  			} else {
  				_compute_heading_from_2D_vector(_yaw_setpoint, v);
  			}
  		}
  
  	} else {
  		_yaw_lock = false;
  		_yaw_setpoint = NAN;
  	}
  }
  
  bool FlightTaskAuto::_isFinite(const position_setpoint_s &sp)
  {
  	return (PX4_ISFINITE(sp.lat) && PX4_ISFINITE(sp.lon) && PX4_ISFINITE(sp.alt));
  }
  
  bool FlightTaskAuto::_evaluateGlobalReference()
  {
  	// check if reference has changed and update.
  	// Only update if reference timestamp has changed AND no valid reference altitude
  	// is available.
  	// TODO: this needs to be revisited and needs a more clear implementation
  	if (_sub_vehicle_local_position.get().ref_timestamp == _time_stamp_reference && PX4_ISFINITE(_reference_altitude)) {
  		// don't need to update anything
  		return true;
  	}
  
  	double ref_lat = _sub_vehicle_local_position.get().ref_lat;
  	double ref_lon = _sub_vehicle_local_position.get().ref_lon;
  	_reference_altitude = _sub_vehicle_local_position.get().ref_alt;
  
  	if (!_sub_vehicle_local_position.get().z_global) {
  		// we have no valid global altitude
  		// set global reference to local reference
  		_reference_altitude = 0.0f;
  	}
  
  	if (!_sub_vehicle_local_position.get().xy_global) {
  		// we have no valid global alt/lat
  		// set global reference to local reference
  		ref_lat = 0.0;
  		ref_lon = 0.0;
  	}
  
  	// init projection
  	map_projection_init(&_reference_position, ref_lat, ref_lon);
  
  	// check if everything is still finite
  	return PX4_ISFINITE(_reference_altitude) && PX4_ISFINITE(ref_lat) && PX4_ISFINITE(ref_lon);
  }
  
  void FlightTaskAuto::_setDefaultConstraints()
  {
  	FlightTask::_setDefaultConstraints();
  
  	// only adjust limits if the new limit is lower
  	if (_constraints.speed_xy >= _param_mpc_xy_cruise.get()) {
  		_constraints.speed_xy = _param_mpc_xy_cruise.get();
  	}
  }
  
  Vector2f FlightTaskAuto::_getTargetVelocityXY()
  {
  	// guard against any bad velocity values
  	const float vx = _sub_triplet_setpoint.get().current.vx;
  	const float vy = _sub_triplet_setpoint.get().current.vy;
  	bool velocity_valid = PX4_ISFINITE(vx) && PX4_ISFINITE(vy) &&
  			      _sub_triplet_setpoint.get().current.velocity_valid;
  
  	if (velocity_valid) {
  		return Vector2f(vx, vy);
  
  	} else {
  		// just return zero speed
  		return Vector2f{};
  	}
  }
  
  State FlightTaskAuto::_getCurrentState()
  {
  	// Calculate the vehicle current state based on the Navigator triplets and the current position.
  	Vector2f u_prev_to_target = Vector2f(_triplet_target - _triplet_prev_wp).unit_or_zero();
  	Vector2f pos_to_target(_triplet_target - _position);
  	Vector2f prev_to_pos(_position - _triplet_prev_wp);
  	// Calculate the closest point to the vehicle position on the line prev_wp - target
  	_closest_pt = Vector2f(_triplet_prev_wp) + u_prev_to_target * (prev_to_pos * u_prev_to_target);
  
  	State return_state = State::none;
  
  	if (u_prev_to_target * pos_to_target < 0.0f) {
  		// Target is behind.
  		return_state = State::target_behind;
  
  	} else if (u_prev_to_target * prev_to_pos < 0.0f && prev_to_pos.length() > _target_acceptance_radius) {
  		// Current position is more than cruise speed in front of previous setpoint.
  		return_state = State::previous_infront;
  
  	} else if (Vector2f(Vector2f(_position) - _closest_pt).length() > _target_acceptance_radius) {
  		// Vehicle is more than cruise speed off track.
  		return_state = State::offtrack;
  
  	}
  
  	return return_state;
  }
  
  void FlightTaskAuto::_updateInternalWaypoints()
  {
  	// The internal Waypoints might differ from _triplet_prev_wp, _triplet_target and _triplet_next_wp.
  	// The cases where it differs:
  	// 1. The vehicle already passed the target -> go straight to target
  	// 2. The vehicle is more than cruise speed in front of previous waypoint -> go straight to previous waypoint
  	// 3. The vehicle is more than cruise speed from track -> go straight to closest point on track
  	switch (_current_state) {
  	case State::target_behind:
  		_target = _triplet_target;
  		_prev_wp = _position;
  		_next_wp = _triplet_next_wp;
  		break;
  
  	case State::previous_infront:
  		_next_wp = _triplet_target;
  		_target = _triplet_prev_wp;
  		_prev_wp = _position;
  		break;
  
  	case State::offtrack:
  		_next_wp = _triplet_target;
  		_target = matrix::Vector3f(_closest_pt(0), _closest_pt(1), _triplet_target(2));
  		_prev_wp = _position;
  		break;
  
  	case State::none:
  		_target = _triplet_target;
  		_prev_wp = _triplet_prev_wp;
  		_next_wp = _triplet_next_wp;
  		break;
  
  	default:
  		break;
  
  	}
  }
  
  bool FlightTaskAuto::_compute_heading_from_2D_vector(float &heading, Vector2f v)
  {
  	if (PX4_ISFINITE(v.length()) && v.length() > SIGMA_NORM) {
  		v.normalize();
  		// To find yaw: take dot product of x = (1,0) and v
  		// and multiply by the sign given of cross product of x and v.
  		// Dot product: (x(0)*v(0)+(x(1)*v(1)) = v(0)
  		// Cross product: x(0)*v(1) - v(0)*x(1) = v(1)
  		heading =  sign(v(1)) * wrap_pi(acosf(v(0)));
  		return true;
  	}
  
  	// heading unknown and therefore do not change heading
  	return false;
  }
  