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/**
 * @file ObstacleAvoidance.cpp
 */

#include "ObstacleAvoidance.hpp"
#include "bezier/BezierN.hpp"

using namespace matrix;
using namespace time_literals;

/** Timeout in us for trajectory data to get considered invalid */
static constexpr uint64_t TRAJECTORY_STREAM_TIMEOUT_US = 500_ms;
/** If Flighttask fails, keep 0.5 seconds the current setpoint before going into failsafe land */
static constexpr uint64_t TIME_BEFORE_FAILSAFE = 500_ms;
static constexpr uint64_t Z_PROGRESS_TIMEOUT_US = 2_s;

ObstacleAvoidance::ObstacleAvoidance(ModuleParams *parent) :
	ModuleParams(parent)
{
	_desired_waypoint = empty_trajectory_waypoint;
	_failsafe_position.setNaN();
	_avoidance_point_not_valid_hysteresis.set_hysteresis_time_from(false, TIME_BEFORE_FAILSAFE);
	_no_progress_z_hysteresis.set_hysteresis_time_from(false, Z_PROGRESS_TIMEOUT_US);

}

void ObstacleAvoidance::injectAvoidanceSetpoints(Vector3f &pos_sp, Vector3f &vel_sp, float &yaw_sp,
		float &yaw_speed_sp)
{
	_sub_vehicle_status.update();
	_sub_vehicle_trajectory_waypoint.update();
	_sub_vehicle_trajectory_bezier.update();

	const auto &wp_msg = _sub_vehicle_trajectory_waypoint.get();
	const auto &bezier_msg = _sub_vehicle_trajectory_bezier.get();

	const bool avoidance_data_timeout =
		hrt_elapsed_time((hrt_abstime *)&wp_msg.timestamp) > TRAJECTORY_STREAM_TIMEOUT_US &&
		hrt_elapsed_time((hrt_abstime *)&bezier_msg.timestamp) > hrt_abstime(bezier_msg.control_points[bezier_msg.bezier_order -
							1].delta * 1e6f);

	const bool avoidance_point_valid = wp_msg.waypoints[vehicle_trajectory_waypoint_s::POINT_0].point_valid;
	const bool avoidance_bezier_valid = bezier_msg.bezier_order > 0;

	_avoidance_point_not_valid_hysteresis.set_state_and_update(!avoidance_point_valid
			&& !avoidance_bezier_valid, hrt_absolute_time());

	const bool avoidance_invalid = (avoidance_data_timeout || _avoidance_point_not_valid_hysteresis.get_state());

	if ((_sub_vehicle_status.get().nav_state == vehicle_status_s::NAVIGATION_STATE_AUTO_LOITER) && avoidance_invalid) {
		// if in nav_state LOITER and avoidance isn't healthy, don't inject setpoints from avoidance system
		return;
	}

	if (avoidance_invalid) {
		PX4_WARN("Obstacle Avoidance system failed, loitering");
		_publishVehicleCmdDoLoiter();

		if (!PX4_ISFINITE(_failsafe_position(0)) || !PX4_ISFINITE(_failsafe_position(1))
		    || !PX4_ISFINITE(_failsafe_position(2))) {
			// save vehicle position when entering failsafe
			_failsafe_position = _position;
		}

		pos_sp = _failsafe_position;
		vel_sp.setNaN();
		yaw_sp = NAN;
		yaw_speed_sp = NAN;
		return;

	} else {
		_failsafe_position.setNaN();
	}

	if (avoidance_point_valid) {
		const auto &point0 = wp_msg.waypoints[vehicle_trajectory_waypoint_s::POINT_0];
		pos_sp = Vector3f(point0.position);
		vel_sp = Vector3f(point0.velocity);

		if (!_ext_yaw_active) {
			// inject yaw setpoints only if weathervane isn't active
			yaw_sp =  point0.yaw;
			yaw_speed_sp = point0.yaw_speed;
		}

	} else if (avoidance_bezier_valid) {

		float yaw = NAN, yaw_speed = NAN;
		_generateBezierSetpoints(pos_sp, vel_sp, yaw, yaw_speed);

		if (!_ext_yaw_active) {
			// inject yaw setpoints only if weathervane isn't active
			yaw_sp =  yaw;
			yaw_speed_sp = yaw_speed;
		}
	}
}

void ObstacleAvoidance::_generateBezierSetpoints(matrix::Vector3f &position, matrix::Vector3f &velocity,
		float &yaw, float &yaw_velocity)
{
	const auto &msg =  _sub_vehicle_trajectory_bezier.get();
	int bezier_order = msg.bezier_order;
	matrix::Vector3f bezier_points[bezier_order];
	float bezier_yaws[bezier_order];

	for (int i = 0; i < bezier_order; i++) {
		bezier_points[i] = Vector3f(msg.control_points[i].position);
		bezier_yaws[i] = msg.control_points[i].yaw;
	}

	const float duration_s = msg.control_points[bezier_order - 1].delta;
	const hrt_abstime now = hrt_absolute_time();
	const hrt_abstime start = msg.timestamp;
	const hrt_abstime end = start + hrt_abstime(duration_s * 1e6f);

	float T = NAN;

	if (bezier::calculateT(start, end, now, T) &&
	    bezier::calculateBezierPosVel(bezier_points, bezier_order, T, position, velocity) &&
	    bezier::calculateBezierYaw(bezier_yaws, bezier_order, T, yaw, yaw_velocity)
	   ) {
		// translate bezier velocities T [0;1] into real velocities m/s
		yaw_velocity /= duration_s;
		velocity /= duration_s;

	} else {
		PX4_WARN("Obstacle Avoidance system failed, bad trajectory");
	}
}


void ObstacleAvoidance::updateAvoidanceDesiredWaypoints(const Vector3f &curr_wp, const float curr_yaw,
		const float curr_yawspeed, const Vector3f &next_wp, const float next_yaw, const float next_yawspeed,
		const bool ext_yaw_active, const int wp_type)
{
	_desired_waypoint.timestamp = hrt_absolute_time();
	_desired_waypoint.type = vehicle_trajectory_waypoint_s::MAV_TRAJECTORY_REPRESENTATION_WAYPOINTS;
	_curr_wp = curr_wp;
	_ext_yaw_active = ext_yaw_active;

	curr_wp.copyTo(_desired_waypoint.waypoints[vehicle_trajectory_waypoint_s::POINT_1].position);
	Vector3f(NAN, NAN, NAN).copyTo(_desired_waypoint.waypoints[vehicle_trajectory_waypoint_s::POINT_1].velocity);
	Vector3f(NAN, NAN, NAN).copyTo(_desired_waypoint.waypoints[vehicle_trajectory_waypoint_s::POINT_1].acceleration);

	_desired_waypoint.waypoints[vehicle_trajectory_waypoint_s::POINT_1].yaw = curr_yaw;
	_desired_waypoint.waypoints[vehicle_trajectory_waypoint_s::POINT_1].yaw_speed = curr_yawspeed;
	_desired_waypoint.waypoints[vehicle_trajectory_waypoint_s::POINT_1].point_valid = true;
	_desired_waypoint.waypoints[vehicle_trajectory_waypoint_s::POINT_1].type = wp_type;

	next_wp.copyTo(_desired_waypoint.waypoints[vehicle_trajectory_waypoint_s::POINT_2].position);
	Vector3f(NAN, NAN, NAN).copyTo(_desired_waypoint.waypoints[vehicle_trajectory_waypoint_s::POINT_2].velocity);
	Vector3f(NAN, NAN, NAN).copyTo(_desired_waypoint.waypoints[vehicle_trajectory_waypoint_s::POINT_2].acceleration);

	_desired_waypoint.waypoints[vehicle_trajectory_waypoint_s::POINT_2].yaw = next_yaw;
	_desired_waypoint.waypoints[vehicle_trajectory_waypoint_s::POINT_2].yaw_speed = next_yawspeed;
	_desired_waypoint.waypoints[vehicle_trajectory_waypoint_s::POINT_2].point_valid = true;
}

void ObstacleAvoidance::updateAvoidanceDesiredSetpoints(const Vector3f &pos_sp, const Vector3f &vel_sp, const int type)
{
	pos_sp.copyTo(_desired_waypoint.waypoints[vehicle_trajectory_waypoint_s::POINT_0].position);
	vel_sp.copyTo(_desired_waypoint.waypoints[vehicle_trajectory_waypoint_s::POINT_0].velocity);
	_desired_waypoint.waypoints[vehicle_trajectory_waypoint_s::POINT_0].type = type;
	_desired_waypoint.waypoints[vehicle_trajectory_waypoint_s::POINT_0].point_valid = true;

	_pub_traj_wp_avoidance_desired.publish(_desired_waypoint);

	_desired_waypoint = empty_trajectory_waypoint;
}

void ObstacleAvoidance::checkAvoidanceProgress(const Vector3f &pos, const Vector3f &prev_wp,
		float target_acceptance_radius, const Vector2f &closest_pt)
{
	_position = pos;
	position_controller_status_s pos_control_status = {};
	pos_control_status.timestamp = hrt_absolute_time();

	// vector from previous triplet to current target
	Vector2f prev_to_target = Vector2f(_curr_wp - prev_wp);
	// vector from previous triplet to the vehicle projected position on the line previous-target triplet
	Vector2f prev_to_closest_pt = closest_pt - Vector2f(prev_wp);
	// fraction of the previous-tagerget line that has been flown
	const float prev_curr_travelled = prev_to_closest_pt.length() / prev_to_target.length();

	Vector2f pos_to_target = Vector2f(_curr_wp - _position);

	if (prev_curr_travelled > 1.0f) {
		// if the vehicle projected position on the line previous-target is past the target waypoint,
		// increase the target acceptance radius such that navigator will update the triplets
		pos_control_status.acceptance_radius = pos_to_target.length() + 0.5f;
	}

	const float pos_to_target_z = fabsf(_curr_wp(2) - _position(2));

	bool no_progress_z = (pos_to_target_z > _prev_pos_to_target_z);
	_no_progress_z_hysteresis.set_state_and_update(no_progress_z, hrt_absolute_time());

	if (pos_to_target.length() < target_acceptance_radius && pos_to_target_z > _param_nav_mc_alt_rad.get()
	    && _no_progress_z_hysteresis.get_state()) {
		// vehicle above or below the target waypoint
		pos_control_status.altitude_acceptance = pos_to_target_z + 0.5f;
	}

	_prev_pos_to_target_z = pos_to_target_z;

	// do not check for waypoints yaw acceptance in navigator
	pos_control_status.yaw_acceptance = NAN;

	_pub_pos_control_status.publish(pos_control_status);
}

void ObstacleAvoidance::_publishVehicleCmdDoLoiter()
{
	vehicle_command_s command{};
	command.timestamp = hrt_absolute_time();
	command.command = vehicle_command_s::VEHICLE_CMD_DO_SET_MODE;
	command.param1 = (float)1; // base mode
	command.param3 = (float)0; // sub mode
	command.target_system = 1;
	command.target_component = 1;
	command.source_system = 1;
	command.source_component = 1;
	command.confirmation = false;
	command.from_external = false;
	command.param2 = (float)PX4_CUSTOM_MAIN_MODE_AUTO;
	command.param3 = (float)PX4_CUSTOM_SUB_MODE_AUTO_LOITER;

	// publish the vehicle command
	_pub_vehicle_command.publish(command);
}