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/**
 * @file mission_feasibility_checker.cpp
 * Provides checks if mission is feasible given the navigation capabilities
 *
 * @author Lorenz Meier <lm@inf.ethz.ch>
 * @author Thomas Gubler <thomasgubler@student.ethz.ch>
 * @author Sander Smeets <sander@droneslab.com>
 * @author Nuno Marques <nuno.marques@dronesolutions.io>
 */

#include "mission_feasibility_checker.h"

#include "mission_block.h"
#include "navigator.h"

#include <drivers/drv_pwm_output.h>
#include <lib/geo/geo.h>
#include <lib/mathlib/mathlib.h>
#include <systemlib/mavlink_log.h>
#include <uORB/Subscription.hpp>
#include <px4_platform_common/events.h>

bool
MissionFeasibilityChecker::checkMissionFeasible(const mission_s &mission)
{
	// Reset warning flag
	_navigator->get_mission_result()->warning = false;

	// first check if we have a valid position
	const bool home_valid = _navigator->home_global_position_valid();
	const bool home_alt_valid = _navigator->home_alt_valid();

	// trivial case: A mission with length zero cannot be valid
	if ((int)mission.count <= 0) {
		return false;
	}

	if (!home_alt_valid) {
		mavlink_log_info(_navigator->get_mavlink_log_pub(), "Not yet ready for mission, no position lock.\t");
		events::send(events::ID("navigator_mis_no_pos_lock"), events::Log::Info, "Not yet ready for mission, no position lock");
		return false;
	}

	bool failed = false;

	for (size_t i = 0; i < mission.count; i++) {
		struct mission_item_s missionitem = {};

		bool success = _dataman_client.readSync((dm_item_t)mission.mission_dataman_id, i,
							reinterpret_cast<uint8_t *>(&missionitem),
							sizeof(mission_item_s));

		if (!success) {
			_navigator->get_mission_result()->warning = true;
			/* not supposed to happen unless the datamanager can't access the SD card, etc. */
			return false;
		}

		if (!_feasibility_checker.processNextItem(missionitem, i, mission.count)) {
			failed = true;
			break;
		}

	}

	failed |= _feasibility_checker.someCheckFailed();

	failed |= !checkMissionAgainstGeofence(mission, _navigator->get_home_position()->alt, home_valid);

	_navigator->get_mission_result()->warning = failed;

	return !failed;
}

bool
MissionFeasibilityChecker::checkMissionAgainstGeofence(const mission_s &mission, float home_alt, bool home_valid)
{
	if (_navigator->get_geofence().isHomeRequired() && !home_valid) {
		mavlink_log_critical(_navigator->get_mavlink_log_pub(), "Geofence requires valid home position\t");
		events::send(events::ID("navigator_mis_geofence_no_home"), {events::Log::Error, events::LogInternal::Info},
			     "Geofence requires a valid home position");
		return false;
	}

	/* Check if all mission items are inside the geofence (if we have a valid geofence) */
	if (_navigator->get_geofence().valid()) {
		for (size_t i = 0; i < mission.count; i++) {
			struct mission_item_s missionitem = {};

			bool success = _dataman_client.readSync((dm_item_t)mission.mission_dataman_id, i,
								reinterpret_cast<uint8_t *>(&missionitem),
								sizeof(mission_item_s));

			if (!success) {
				/* not supposed to happen unless the datamanager can't access the SD card, etc. */
				return false;
			}

			if (missionitem.altitude_is_relative && !home_valid) {
				mavlink_log_critical(_navigator->get_mavlink_log_pub(), "Geofence requires valid home position\t");
				events::send(events::ID("navigator_mis_geofence_no_home2"), {events::Log::Error, events::LogInternal::Info},
					     "Geofence requires a valid home position");
				return false;
			}

			// Geofence function checks against home altitude amsl
			missionitem.altitude = missionitem.altitude_is_relative ? missionitem.altitude + home_alt : missionitem.altitude;

			if (MissionBlock::item_contains_position(missionitem) && !_navigator->get_geofence().checkPointAgainstAllGeofences(
				    missionitem.lat, missionitem.lon, missionitem.altitude)) {

				mavlink_log_critical(_navigator->get_mavlink_log_pub(), "Geofence violation for waypoint %zu\t", i + 1);
				events::send<int16_t>(events::ID("navigator_mis_geofence_violation"), {events::Log::Error, events::LogInternal::Info},
						      "Geofence violation for waypoint {1}",
						      i + 1);
				return false;
			}
		}
	}

	return true;
}