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/**
 * @file data_validator.h
 *
 * A data validation class to identify anomalies in data streams
 *
 * @author Lorenz Meier <lorenz@px4.io>
 */

#pragma once

#include <cmath>
#include <stdint.h>

class DataValidator
{
public:
	static const unsigned dimensions = 3;

	DataValidator() = default;
	~DataValidator() = default;

	/**
	 * Put an item into the validator.
	 *
	 * @param val		Item to put
	 */
	void			put(uint64_t timestamp, float val, uint64_t error_count, int priority);

	/**
	 * Put a 3D item into the validator.
	 *
	 * @param val		Item to put
	 */
	void			put(uint64_t timestamp, const float val[dimensions], uint64_t error_count, int priority);

	/**
	 * Get the next sibling in the group
	 *
	 * @return		the next sibling
	 */
	DataValidator		*sibling() { return _sibling; }

	/**
	 * Set the sibling to the next node in the group
	 *
	 */
	void			setSibling(DataValidator *new_sibling) { _sibling = new_sibling; }

	/**
	 * Get the confidence of this validator
	 * @return		the confidence between 0 and 1
	 */
	float			confidence(uint64_t timestamp);

	/**
	 * Get the error count of this validator
	 * @return		the error count
	 */
	uint64_t		error_count() const { return _error_count; }

	/**
	 * Get the values of this validator
	 * @return		the stored value
	 */
	float			*value() { return _value; }

	/**
	 * Get the used status of this validator
	 * @return		true if this validator ever saw data
	 */
	bool			used() const { return (_time_last > 0); }

	/**
	 * Get the priority of this validator
	 * @return		the stored priority
	 */
	int			priority() const { return _priority; }

	/**
	 * Get the error state of this validator
	 * @return		the bitmask with the error status
	 */
	uint32_t		state() const { return _error_mask; }

	/**
	 * Reset the error state of this validator
	 */
	void			reset_state() { _error_mask = ERROR_FLAG_NO_ERROR; }

	/**
	 * Get the RMS values of this validator
	 * @return		the stored RMS
	 */
	float			*rms() { return _rms; }

	/**
	 * Get the vibration offset
	 * @return		the stored vibration offset
	 */
	float			*vibration_offset() { return _vibe; }

	/**
	 * Print the validator value
	 *
	 */
	void			print();

	/**
	 * Set the timeout value
	 *
	 * @param timeout_interval_us The timeout interval in microseconds
	 */
	void			set_timeout(uint32_t timeout_interval_us) { _timeout_interval = timeout_interval_us; }

	/**
	 * Set the equal count threshold
	 *
	 * @param threshold The number of equal values before considering the sensor stale
	 */
	void			set_equal_value_threshold(uint32_t threshold) { _value_equal_count_threshold = threshold; }

	/**
	 * Get the timeout value
	 *
	 * @return The timeout interval in microseconds
	 */
	uint32_t		get_timeout() const { return _timeout_interval; }

	/**
	 * Data validator error states
	 */
	static constexpr uint32_t ERROR_FLAG_NO_ERROR      	= (0x00000000U);
	static constexpr uint32_t ERROR_FLAG_NO_DATA       	= (0x00000001U);
	static constexpr uint32_t ERROR_FLAG_STALE_DATA    	= (0x00000001U << 1);
	static constexpr uint32_t ERROR_FLAG_TIMEOUT 	   	= (0x00000001U << 2);
	static constexpr uint32_t ERROR_FLAG_HIGH_ERRCOUNT 	= (0x00000001U << 3);
	static constexpr uint32_t ERROR_FLAG_HIGH_ERRDENSITY 	= (0x00000001U << 4);

private:
	uint32_t _error_mask{ERROR_FLAG_NO_ERROR};	/**< sensor error state */

	uint32_t _timeout_interval{20000};		/**< interval in which the datastream times out in us */

	uint64_t _time_last{0};				/**< last timestamp */
	uint64_t _event_count{0};			/**< total data counter */
	uint64_t _error_count{0};			/**< error count */

	int _error_density{0};				/**< ratio between successful reads and errors */

	int _priority{0};				/**< sensor nominal priority */

	float _mean[dimensions] {};			/**< mean of value */
	float _lp[dimensions] {};			/**< low pass value */
	float _M2[dimensions] {};			/**< RMS component value */
	float _rms[dimensions] {};			/**< root mean square error */
	float _value[dimensions] {};			/**< last value */
	float _vibe[dimensions] {};			/**< vibration level, in sensor unit */

	unsigned _value_equal_count{0};			/**< equal values in a row */
	unsigned _value_equal_count_threshold{VALUE_EQUAL_COUNT_DEFAULT};	/**< when to consider an equal count as a problem */

	DataValidator *_sibling{nullptr};		/**< sibling in the group */

	static const constexpr unsigned NORETURN_ERRCOUNT = 10000;	/**< if the error count reaches this value, return sensor as invalid */
	static const constexpr float ERROR_DENSITY_WINDOW = 100.0f; 	/**< window in measurement counts for errors */
	static const constexpr unsigned VALUE_EQUAL_COUNT_DEFAULT = 100;	/**< if the sensor value is the same (accumulated also between axes) this many times, flag it */

	/* we don't want this class to be copied */
	DataValidator(const DataValidator &) = delete;
	DataValidator operator=(const DataValidator &) = delete;
};