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#include "DifferentialPosControl.hpp"

using namespace time_literals;

DifferentialPosControl::DifferentialPosControl(ModuleParams *parent) : ModuleParams(parent)
{
	_differential_velocity_setpoint_pub.advertise();
	_rover_position_setpoint_pub.advertise();
	_pure_pursuit_status_pub.advertise();

	// Initially set to NaN to indicate that the rover has no position setpoint
	_rover_position_setpoint.position_ned[0] = NAN;
	_rover_position_setpoint.position_ned[1] = NAN;

	updateParams();
}

void DifferentialPosControl::updateParams()
{
	ModuleParams::updateParams();
	_max_yaw_rate = _param_ro_yaw_rate_limit.get() * M_DEG_TO_RAD_F;
}

void DifferentialPosControl::updatePosControl()
{
	const hrt_abstime timestamp_prev = _timestamp;
	_timestamp = hrt_absolute_time();
	_dt = math::constrain(_timestamp - timestamp_prev, 1_ms, 5000_ms) * 1e-6f;

	updateSubscriptions();

	if (_vehicle_control_mode.flag_control_position_enabled && _vehicle_control_mode.flag_armed && runSanityChecks()) {
		if (_vehicle_control_mode.flag_control_offboard_enabled) {
			generatePositionSetpoint();
		}

		generateVelocitySetpoint();

	}

}

void DifferentialPosControl::updateSubscriptions()
{
	if (_vehicle_control_mode_sub.updated()) {
		_vehicle_control_mode_sub.copy(&_vehicle_control_mode);
	}

	if (_vehicle_attitude_sub.updated()) {
		vehicle_attitude_s vehicle_attitude{};
		_vehicle_attitude_sub.copy(&vehicle_attitude);
		_vehicle_attitude_quaternion = matrix::Quatf(vehicle_attitude.q);
		_vehicle_yaw = matrix::Eulerf(_vehicle_attitude_quaternion).psi();
	}

	if (_vehicle_local_position_sub.updated()) {
		vehicle_local_position_s vehicle_local_position{};
		_vehicle_local_position_sub.copy(&vehicle_local_position);

		if (!_global_ned_proj_ref.isInitialized()
		    || (_global_ned_proj_ref.getProjectionReferenceTimestamp() != vehicle_local_position.ref_timestamp)) {
			_global_ned_proj_ref.initReference(vehicle_local_position.ref_lat, vehicle_local_position.ref_lon,
							   vehicle_local_position.ref_timestamp);
		}

		_curr_pos_ned = Vector2f(vehicle_local_position.x, vehicle_local_position.y);
		Vector3f velocity_ned(vehicle_local_position.vx, vehicle_local_position.vy, vehicle_local_position.vz);
		Vector3f velocity_xyz = _vehicle_attitude_quaternion.rotateVectorInverse(velocity_ned);
		Vector2f velocity_2d = Vector2f(velocity_xyz(0), velocity_xyz(1));
		_vehicle_speed = velocity_2d.norm() > _param_ro_speed_th.get() ? sign(velocity_2d(0)) * velocity_2d.norm() : 0.f;
	}

}

void DifferentialPosControl::generatePositionSetpoint()
{
	if (_offboard_control_mode_sub.updated()) {
		_offboard_control_mode_sub.copy(&_offboard_control_mode);
	}

	if (!_offboard_control_mode.position) {
		return;
	}

	trajectory_setpoint_s trajectory_setpoint{};
	_trajectory_setpoint_sub.copy(&trajectory_setpoint);

	// Translate trajectory setpoint to rover position setpoint
	rover_position_setpoint_s rover_position_setpoint{};
	rover_position_setpoint.timestamp = _timestamp;
	rover_position_setpoint.position_ned[0] = trajectory_setpoint.position[0];
	rover_position_setpoint.position_ned[1] = trajectory_setpoint.position[1];
	rover_position_setpoint.cruising_speed = _param_ro_speed_limit.get();
	rover_position_setpoint.yaw = NAN;
	_rover_position_setpoint_pub.publish(rover_position_setpoint);

}

void DifferentialPosControl::generateVelocitySetpoint()
{
	if (_vehicle_control_mode.flag_control_manual_enabled && _vehicle_control_mode.flag_control_position_enabled) {
		manualPositionMode();

	} else if (_vehicle_control_mode.flag_control_auto_enabled) {
		autoPositionMode();

	} else if (_rover_position_setpoint_sub.copy(&_rover_position_setpoint)
		   && PX4_ISFINITE(_rover_position_setpoint.position_ned[0]) && PX4_ISFINITE(_rover_position_setpoint.position_ned[1])) {
		goToPositionMode();
	}

}

void DifferentialPosControl::manualPositionMode()
{
	manual_control_setpoint_s manual_control_setpoint{};
	_manual_control_setpoint_sub.copy(&manual_control_setpoint);

	const float speed_setpoint = math::interpolate<float>(manual_control_setpoint.throttle,
				     -1.f, 1.f, -_param_ro_speed_limit.get(), _param_ro_speed_limit.get());
	const float bearing_scaling = math::min(_max_yaw_rate / _param_ro_yaw_p.get(),
						_param_rd_trans_drv_trn.get() - FLT_EPSILON);
	const float bearing_delta = math::interpolate<float>(math::deadzone(manual_control_setpoint.roll,
				    _param_ro_yaw_stick_dz.get()), -1.f, 1.f, -bearing_scaling, bearing_scaling);

	if (fabsf(speed_setpoint) < FLT_EPSILON) { // Turn on spot
		_course_control = false;
		const float bearing_setpoint = matrix::wrap_pi(_vehicle_yaw + bearing_delta);
		differential_velocity_setpoint_s differential_velocity_setpoint{};
		differential_velocity_setpoint.timestamp = _timestamp;
		differential_velocity_setpoint.speed = 0.f;
		differential_velocity_setpoint.bearing = bearing_setpoint;
		_differential_velocity_setpoint_pub.publish(differential_velocity_setpoint);

	} else if (fabsf(bearing_delta) > FLT_EPSILON) { // Closed loop yaw rate control
		_course_control = false;
		const float bearing_setpoint = matrix::wrap_pi(_vehicle_yaw + bearing_delta);
		differential_velocity_setpoint_s differential_velocity_setpoint{};
		differential_velocity_setpoint.timestamp = _timestamp;
		differential_velocity_setpoint.speed = speed_setpoint;
		differential_velocity_setpoint.bearing = bearing_setpoint;
		_differential_velocity_setpoint_pub.publish(differential_velocity_setpoint);

	} else { // Course control if the steering input is zero (keep driving on a straight line)
		if (!_course_control) {
			_pos_ctl_course_direction = Vector2f(cos(_vehicle_yaw), sin(_vehicle_yaw));
			_pos_ctl_start_position_ned = _curr_pos_ned;
			_course_control = true;
		}

		// Construct a 'target waypoint' for course control s.t. it is never within the maximum lookahead of the rover
		const Vector2f start_to_curr_pos = _curr_pos_ned - _pos_ctl_start_position_ned;
		const float vector_scaling = fabsf(start_to_curr_pos * _pos_ctl_course_direction) + _param_pp_lookahd_max.get();
		const Vector2f target_waypoint_ned = _pos_ctl_start_position_ned + sign(speed_setpoint) *
						     vector_scaling * _pos_ctl_course_direction;
		pure_pursuit_status_s pure_pursuit_status{};
		pure_pursuit_status.timestamp = _timestamp;
		const float bearing_setpoint = PurePursuit::calcTargetBearing(pure_pursuit_status, _param_pp_lookahd_gain.get(),
					       _param_pp_lookahd_max.get(), _param_pp_lookahd_min.get(), target_waypoint_ned, _pos_ctl_start_position_ned,
					       _curr_pos_ned, fabsf(speed_setpoint));
		_pure_pursuit_status_pub.publish(pure_pursuit_status);
		differential_velocity_setpoint_s differential_velocity_setpoint{};
		differential_velocity_setpoint.timestamp = _timestamp;
		differential_velocity_setpoint.speed = speed_setpoint;
		differential_velocity_setpoint.bearing = speed_setpoint > -FLT_EPSILON ? bearing_setpoint : matrix::wrap_pi(
					bearing_setpoint + M_PI_F);
		_differential_velocity_setpoint_pub.publish(differential_velocity_setpoint);
	}
}

void DifferentialPosControl::autoPositionMode()
{
	if (_position_setpoint_triplet_sub.updated()) {
		position_setpoint_triplet_s position_setpoint_triplet{};
		_position_setpoint_triplet_sub.copy(&position_setpoint_triplet);
		_curr_wp_type = position_setpoint_triplet.current.type;

		RoverControl::globalToLocalSetpointTriplet(_curr_wp_ned, _prev_wp_ned, _next_wp_ned, position_setpoint_triplet,
				_curr_pos_ned, _global_ned_proj_ref);

		_waypoint_transition_angle = RoverControl::calcWaypointTransitionAngle(_prev_wp_ned, _curr_wp_ned, _next_wp_ned);

		// Waypoint cruising speed
		_cruising_speed = position_setpoint_triplet.current.cruising_speed > 0.f ? math::constrain(
					  position_setpoint_triplet.current.cruising_speed, 0.f, _param_ro_speed_limit.get()) : _param_ro_speed_limit.get();
	}

	// Distances to waypoints
	const float distance_to_curr_wp = sqrt(powf(_curr_pos_ned(0) - _curr_wp_ned(0),
					       2) + powf(_curr_pos_ned(1) - _curr_wp_ned(1), 2));

	// Check stopping conditions
	bool auto_stop{false};

	if (_curr_wp_type == position_setpoint_s::SETPOINT_TYPE_LAND
	    || _curr_wp_type == position_setpoint_s::SETPOINT_TYPE_IDLE
	    || !_next_wp_ned.isAllFinite()) { // Check stopping conditions
		auto_stop = distance_to_curr_wp < _param_nav_acc_rad.get();
	}

	if (auto_stop) {
		differential_velocity_setpoint_s differential_velocity_setpoint{};
		differential_velocity_setpoint.timestamp = _timestamp;
		differential_velocity_setpoint.speed = 0.f;
		differential_velocity_setpoint.bearing = _vehicle_yaw;
		_differential_velocity_setpoint_pub.publish(differential_velocity_setpoint);

	} else {
		const float speed_setpoint = calcSpeedSetpoint(_cruising_speed, distance_to_curr_wp, _param_ro_decel_limit.get(),
					     _param_ro_jerk_limit.get(), _waypoint_transition_angle, _param_ro_speed_limit.get(), _param_rd_trans_drv_trn.get(),
					     _param_rd_miss_spd_gain.get(), _curr_wp_type);
		pure_pursuit_status_s pure_pursuit_status{};
		pure_pursuit_status.timestamp = _timestamp;
		const float bearing_setpoint = PurePursuit::calcTargetBearing(pure_pursuit_status, _param_pp_lookahd_gain.get(),
					       _param_pp_lookahd_max.get(), _param_pp_lookahd_min.get(), _curr_wp_ned, _prev_wp_ned, _curr_pos_ned,
					       fabsf(speed_setpoint));
		_pure_pursuit_status_pub.publish(pure_pursuit_status);
		differential_velocity_setpoint_s differential_velocity_setpoint{};
		differential_velocity_setpoint.timestamp = _timestamp;
		differential_velocity_setpoint.speed = speed_setpoint;
		differential_velocity_setpoint.bearing = bearing_setpoint;
		_differential_velocity_setpoint_pub.publish(differential_velocity_setpoint);
	}

}

float DifferentialPosControl::calcSpeedSetpoint(const float cruising_speed, const float distance_to_curr_wp,
		const float max_decel, const float max_jerk, const float waypoint_transition_angle, const float max_speed,
		const float trans_drv_trn, const float miss_spd_gain, int curr_wp_type)
{
	// Upcoming stop
	if (max_decel > FLT_EPSILON && max_jerk > FLT_EPSILON && (!PX4_ISFINITE(waypoint_transition_angle)
			|| _waypoint_transition_angle < M_PI_F - trans_drv_trn || curr_wp_type == position_setpoint_s::SETPOINT_TYPE_LAND
			|| curr_wp_type == position_setpoint_s::SETPOINT_TYPE_IDLE)) {
		const float straight_line_speed = math::trajectory::computeMaxSpeedFromDistance(max_jerk,
						  max_decel, distance_to_curr_wp, 0.f);
		return math::min(straight_line_speed, cruising_speed);
	}

	// Straight line speed
	if (max_jerk > FLT_EPSILON && max_decel > FLT_EPSILON && miss_spd_gain > FLT_EPSILON) {
		const float speed_reduction = math::constrain(miss_spd_gain * math::interpolate(M_PI_F - _waypoint_transition_angle,
					      0.f, M_PI_F, 0.f, 1.f), 0.f, 1.f);
		const float straight_line_speed = math::trajectory::computeMaxSpeedFromDistance(max_jerk, max_decel,
						  distance_to_curr_wp,
						  max_speed * (1.f - speed_reduction));
		return math::min(straight_line_speed, cruising_speed);
	}

	return cruising_speed; // Fallthrough

}

void DifferentialPosControl::goToPositionMode()
{
	const Vector2f target_waypoint_ned(_rover_position_setpoint.position_ned[0], _rover_position_setpoint.position_ned[1]);
	const float distance_to_target = (target_waypoint_ned - _curr_pos_ned).norm();

	if (distance_to_target > _param_nav_acc_rad.get()) {
		float speed_setpoint = math::trajectory::computeMaxSpeedFromDistance(_param_ro_jerk_limit.get(),
				       _param_ro_decel_limit.get(), distance_to_target, 0.f);
		const float max_speed = PX4_ISFINITE(_rover_position_setpoint.cruising_speed) ?
					_rover_position_setpoint.cruising_speed :
					_param_ro_speed_limit.get();
		speed_setpoint = math::min(speed_setpoint, max_speed);
		pure_pursuit_status_s pure_pursuit_status{};
		pure_pursuit_status.timestamp = _timestamp;
		const float bearing_setpoint = PurePursuit::calcTargetBearing(pure_pursuit_status, _param_pp_lookahd_gain.get(),
					       _param_pp_lookahd_max.get(), _param_pp_lookahd_min.get(), target_waypoint_ned, _curr_pos_ned,
					       _curr_pos_ned, fabsf(speed_setpoint));
		_pure_pursuit_status_pub.publish(pure_pursuit_status);
		differential_velocity_setpoint_s differential_velocity_setpoint{};
		differential_velocity_setpoint.timestamp = _timestamp;
		differential_velocity_setpoint.speed = speed_setpoint;
		differential_velocity_setpoint.bearing = bearing_setpoint;
		_differential_velocity_setpoint_pub.publish(differential_velocity_setpoint);

	} else {
		differential_velocity_setpoint_s differential_velocity_setpoint{};
		differential_velocity_setpoint.timestamp = _timestamp;
		differential_velocity_setpoint.speed = 0.f;
		differential_velocity_setpoint.bearing = _vehicle_yaw;
		_differential_velocity_setpoint_pub.publish(differential_velocity_setpoint);
	}
}

bool DifferentialPosControl::runSanityChecks()
{
	bool ret = true;

	if (_param_ro_yaw_rate_limit.get() < FLT_EPSILON) {
		ret = false;
	}

	if (_param_ro_speed_limit.get() < FLT_EPSILON) {
		ret = false;
	}

	_prev_param_check_passed = ret;
	return ret;
}