/** Statistic collection.
 *
 * @file
 * @author Steffen Vogel <post@steffenvogel.de>
 * @copyright 2014-2022, Institute for Automation of Complex Power Systems, EONERC
 * @license Apache 2.0
 *********************************************************************************/

#pragma once

#include <cstdint>
#include <jansson.h>

#include <unordered_map>
#include <memory>
#include <string>

#include <villas/common.hpp>
#include <villas/hist.hpp>
#include <villas/table.hpp>
#include <villas/signal.hpp>
#include <villas/log.hpp>

namespace villas {
namespace node {

/* Forward declarations */
struct Sample;
class Node;

}

class Stats {

public:
	using Ptr = std::shared_ptr<Stats>;

	enum class Format {
		HUMAN,
		JSON,
		MATLAB
	};

	enum class Metric {
		SMPS_SKIPPED,		/**< Counter for skipped samples due to hooks. */
		SMPS_REORDERED,		/**< Counter for reordered samples. */

		/* Timings */
		GAP_SAMPLE,		/**< Histogram for inter sample timestamps (as sent by remote). */
		GAP_RECEIVED,		/**< Histogram for inter sample arrival time (as seen by this instance). */
		OWD,			/**< Histogram for one-way-delay (OWD) of received samples. */
		AGE,			/**< Processing time of packets within VILLASnode. */
		SIGNAL_COUNT,		/**< Number of signals per sample. */

		/* RTP metrics */
		RTP_LOSS_FRACTION,	/**< Fraction lost since last RTP SR/RR. */
		RTP_PKTS_LOST,		/**< Cumul. no. pkts lost. */
		RTP_JITTER		/**< Interarrival jitter. */
	};

	enum class Type {
		LAST,
		HIGHEST,
		LOWEST,
		MEAN,
		VAR,
		STDDEV,
		TOTAL
	};

protected:
	std::unordered_map<Metric, villas::Hist> histograms;

	struct MetricDescription {
		const char *name;
		const char *unit;
		const char *desc;
	};

	struct TypeDescription {
		const char *name;
		enum node::SignalType signal_type;
	};

	static std::shared_ptr<Table> table;

	static void setupTable();

	Logger logger;

public:

	Stats(int buckets, int warmup);

	static
	enum Format lookupFormat(const std::string &str);

	static
	enum Metric lookupMetric(const std::string &str);

	static
	enum Type lookupType(const std::string &str);

	void update(enum Metric id, double val);

	void reset();

	json_t * toJson() const;

	static
	void printHeader(enum Format fmt);

	void printPeriodic(FILE *f, enum Format fmt, node::Node *n) const;

	void print(FILE *f, enum Format fmt, int verbose) const;

	union node::SignalData getValue(enum Metric sm, enum Type st) const;

	const Hist & getHistogram(enum Metric sm) const;

	static std::unordered_map<Metric, MetricDescription> metrics;
	static std::unordered_map<Type, TypeDescription> types;
	static std::vector<TableColumn> columns;
};

} // namespace villas