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/**
 * @file data_validator_group.cpp
 *
 * A data validation group to identify anomalies in data streams
 *
 * @author Lorenz Meier <lorenz@px4.io>
 */

#include "data_validator_group.h"
#include <ecl/ecl.h>
#include <cfloat>

DataValidatorGroup::DataValidatorGroup(unsigned siblings) :
	_first(nullptr),
	_curr_best(-1),
	_prev_best(-1),
	_first_failover_time(0),
	_toggle_count(0)
{
	DataValidator *next = _first;

	for (unsigned i = 0; i < siblings; i++) {
		next = new DataValidator(next);
	}

	_first = next;
	_timeout_interval_us = _first->get_timeout();
}

DataValidatorGroup::~DataValidatorGroup()
{
	while (_first) {
		DataValidator* next = _first->sibling();
		delete (_first);
		_first = next;
	}
}

DataValidator *DataValidatorGroup::add_new_validator()
{
	DataValidator *validator = new DataValidator(_first);
	if (!validator) {
		return nullptr;
	}
	_first = validator;
	_first->set_timeout(_timeout_interval_us);
	return _first;
}

void
DataValidatorGroup::set_timeout(uint32_t timeout_interval_us)
{
	DataValidator *next = _first;

	while (next != nullptr) {
		next->set_timeout(timeout_interval_us);
		next = next->sibling();
	}
	_timeout_interval_us = timeout_interval_us;
}

void
DataValidatorGroup::set_equal_value_threshold(uint32_t threshold)
{
	DataValidator *next = _first;

	while (next != nullptr) {
		next->set_equal_value_threshold(threshold);
		next = next->sibling();
	}
}


void
DataValidatorGroup::put(unsigned index, uint64_t timestamp, float val[3], uint64_t error_count, int priority)
{
	DataValidator *next = _first;
	unsigned i = 0;

	while (next != nullptr) {
		if (i == index) {
			next->put(timestamp, val, error_count, priority);
			break;
		}
		next = next->sibling();
		i++;
	}
}

float*
DataValidatorGroup::get_best(uint64_t timestamp, int *index)
{
	DataValidator *next = _first;

	// XXX This should eventually also include voting
	int pre_check_best = _curr_best;
	float pre_check_confidence = 1.0f;
	int pre_check_prio = -1;
	float max_confidence = -1.0f;
	int max_priority = -1000;
	int max_index = -1;
	DataValidator *best = nullptr;

	unsigned i = 0;

	while (next != nullptr) {
		float confidence = next->confidence(timestamp);

		if (static_cast<int>(i) == pre_check_best) {
			pre_check_prio = next->priority();
			pre_check_confidence = confidence;
		}

		/*
		 * Switch if:
		 * 1) the confidence is higher and priority is equal or higher
		 * 2) the confidence is no less than 1% different and the priority is higher
		 */
		if ((((max_confidence < MIN_REGULAR_CONFIDENCE) && (confidence >= MIN_REGULAR_CONFIDENCE)) ||
			(confidence > max_confidence && (next->priority() >= max_priority)) ||
			(fabsf(confidence - max_confidence) < 0.01f && (next->priority() > max_priority))
			) && (confidence > 0.0f)) {
			max_index = i;
			max_confidence = confidence;
			max_priority = next->priority();
			best = next;
		}

		next = next->sibling();
		i++;
	}

	/* the current best sensor is not matching the previous best sensor,
	 * or the only sensor went bad */
	if (max_index != _curr_best || ((max_confidence < FLT_EPSILON) && (_curr_best >= 0))) {

		bool true_failsafe = true;

		/* check whether the switch was a failsafe or preferring a higher priority sensor */
		if (pre_check_prio != -1 && pre_check_prio < max_priority &&
			fabsf(pre_check_confidence - max_confidence) < 0.1f) {
			/* this is not a failover */
			true_failsafe = false;
			/* reset error flags, this is likely a hotplug sensor coming online late */
			best->reset_state();
		}

		/* if we're no initialized, initialize the bookkeeping but do not count a failsafe */
		if (_curr_best < 0) {
			_prev_best = max_index;
		} else {
			/* we were initialized before, this is a real failsafe */
			_prev_best = pre_check_best;

			if (true_failsafe) {
				_toggle_count++;

				/* if this is the first time, log when we failed */
				if (_first_failover_time == 0) {
					_first_failover_time = timestamp;
				}
			}
		}

		/* for all cases we want to keep a record of the best index */
		_curr_best = max_index;
	}
	*index = max_index;
	return (best) ? best->value() : nullptr;
}

float
DataValidatorGroup::get_vibration_factor(uint64_t timestamp)
{
	DataValidator *next = _first;

	float vibe = 0.0f;

	/* find the best RMS value of a non-timed out sensor */
	while (next != nullptr) {

		if (next->confidence(timestamp) > 0.5f) {
			float* rms = next->rms();

			for (unsigned j = 0; j < 3; j++) {
				if (rms[j] > vibe) {
					vibe = rms[j];
				}
			}
		}

		next = next->sibling();
	}

	return vibe;
}

float
DataValidatorGroup::get_vibration_offset(uint64_t timestamp, int axis)
{
	DataValidator *next = _first;

	float vibe = -1.0f;

	/* find the best vibration value of a non-timed out sensor */
	while (next != nullptr) {

		if (next->confidence(timestamp) > 0.5f) {
			float* vibration_offset = next->vibration_offset();

			if (vibe < 0.0f || vibration_offset[axis] < vibe) {
				vibe = vibration_offset[axis];
			}
		}

		next = next->sibling();
	}

	return vibe;
}

void
DataValidatorGroup::print()
{
	/* print the group's state */
	ECL_INFO("validator: best: %d, prev best: %d, failsafe: %s (%u events)",
		_curr_best, _prev_best, (_toggle_count > 0) ? "YES" : "NO",
		_toggle_count);

	DataValidator *next = _first;
	unsigned i = 0;

	while (next != nullptr) {
		if (next->used()) {
			uint32_t flags = next->state();

			ECL_INFO("sensor #%u, prio: %d, state:%s%s%s%s%s%s", i, next->priority(),
			((flags & DataValidator::ERROR_FLAG_NO_DATA) ? " OFF" : ""),
			((flags & DataValidator::ERROR_FLAG_STALE_DATA) ? " STALE" : ""),
			((flags & DataValidator::ERROR_FLAG_TIMEOUT) ? " TOUT" : ""),
			((flags & DataValidator::ERROR_FLAG_HIGH_ERRCOUNT) ? " ECNT" : ""),
			((flags & DataValidator::ERROR_FLAG_HIGH_ERRDENSITY) ? " EDNST" : ""),
			((flags == DataValidator::ERROR_FLAG_NO_ERROR) ? " OK" : ""));

			next->print();
		}
		next = next->sibling();
		i++;
	}
}

unsigned
DataValidatorGroup::failover_count()
{
	return _toggle_count;
}

int
DataValidatorGroup::failover_index()
{
	DataValidator *next = _first;
	unsigned i = 0;

	while (next != nullptr) {
		if (next->used() && (next->state() != DataValidator::ERROR_FLAG_NO_ERROR) && (i == (unsigned)_prev_best)) {
			return i;
		}
		next = next->sibling();
		i++;
	}
	return -1;
}

uint32_t
DataValidatorGroup::failover_state()
{
	DataValidator *next = _first;
	unsigned i = 0;

	while (next != nullptr) {
		if (next->used() && (next->state() != DataValidator::ERROR_FLAG_NO_ERROR) && (i == (unsigned)_prev_best)) {
			return next->state();
		}
		next = next->sibling();
		i++;
	}
	return DataValidator::ERROR_FLAG_NO_ERROR;
}