/** Statistic collection.
 *
 * @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
 * @copyright 2014-2020, Institute for Automation of Complex Power Systems, EONERC
 * @license GNU General Public License (version 3)
 *
 * VILLASnode
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *********************************************************************************/

#include <cstring>

#include <villas/stats.hpp>
#include <villas/hist.hpp>
#include <villas/timing.h>
#include <villas/node.h>
#include <villas/utils.hpp>
#include <villas/log.h>
#include <villas/node.h>
#include <villas/table.hpp>

using namespace villas;
using namespace villas::utils;

std::unordered_map<Stats::Metric, Stats::MetricDescription> Stats::metrics = {
	{ Stats::Metric::SMPS_SKIPPED, 		{ "skipped",		"samples", "Skipped samples and the distance between them" 		}},
	{ Stats::Metric::SMPS_REORDERED, 	{ "reordered",		"samples", "Reordered samples and the distance between them" 		}},
	{ Stats::Metric::GAP_SAMPLE, 		{ "gap_sent",		"seconds", "Inter-message timestamps (as sent by remote)" 		}},
	{ Stats::Metric::GAP_RECEIVED, 		{ "gap_received",	"seconds", "Inter-message arrival time (as received by this instance)" 	}},
	{ Stats::Metric::OWD, 			{ "owd",		"seconds", "One-way-delay (OWD) of received messages" 			}},
	{ Stats::Metric::AGE, 			{ "age",		"seconds", "Processing time of packets within the from receive to sent" }},
	{ Stats::Metric::RTP_LOSS_FRACTION, 	{ "rtp.loss_fraction",	"percent", "Fraction lost since last RTP SR/RR."			}},
	{ Stats::Metric::RTP_PKTS_LOST, 	{ "rtp.pkts_lost",	"packets", "Cumulative number of packtes lost" 				}},
	{ Stats::Metric::RTP_JITTER, 		{ "rtp.jitter",		"seconds", "Interarrival jitter" 					}},
};

std::unordered_map<Stats::Type, Stats::TypeDescription> Stats::types = {
	{ Stats::Type::LAST,			{ "last",		SignalType::FLOAT }},
	{ Stats::Type::HIGHEST,			{ "highest",		SignalType::FLOAT }},
	{ Stats::Type::LOWEST,			{ "lowest",		SignalType::FLOAT }},
	{ Stats::Type::MEAN,			{ "mean",		SignalType::FLOAT }},
	{ Stats::Type::VAR,			{ "var",		SignalType::FLOAT }},
	{ Stats::Type::STDDEV,			{ "stddev",		SignalType::FLOAT }},
	{ Stats::Type::TOTAL,			{ "total",		SignalType::INTEGER }}
};

std::vector<TableColumn> Stats::columns = {
	{ 10, TableColumn::Alignment::LEFT,  "Node",		"%s"		 },
	{ 10, TableColumn::Alignment::RIGHT, "Recv",		"%ju", "pkts"	 },
	{ 10, TableColumn::Alignment::RIGHT, "Sent",		"%ju", "pkts"	 },
	{ 10, TableColumn::Alignment::RIGHT, "Drop",		"%ju", "pkts"	 },
	{ 10, TableColumn::Alignment::RIGHT, "Skip",		"%ju", "pkts"	 },
	{ 10, TableColumn::Alignment::RIGHT, "OWD last",	"%lf", "secs"	 },
	{ 10, TableColumn::Alignment::RIGHT, "OWD mean",	"%lf", "secs"	 },
	{ 10, TableColumn::Alignment::RIGHT, "Rate last",	"%lf", "pkt/sec" },
	{ 10, TableColumn::Alignment::RIGHT, "Rate mean",	"%lf", "pkt/sec" },
	{ 10, TableColumn::Alignment::RIGHT, "Age mean",	"%lf", "secs"	 },
	{ 10, TableColumn::Alignment::RIGHT, "Age Max",		"%lf", "sec"	 }
};

enum Stats::Format Stats::lookupFormat(const std::string &str)
{
	if      (str == "human")
		return Format::HUMAN;
	else if (str == "json")
		return Format::JSON;
	else if (str == "matlab")
	 	return Format::MATLAB;

	throw std::invalid_argument("Invalid format");
}

enum Stats::Metric Stats::lookupMetric(const std::string &str)
{
	for (auto m : metrics) {
		if (str == m.second.name)
			return m.first;
	}

	throw std::invalid_argument("Invalid metric");
}

enum Stats::Type Stats::lookupType(const std::string &str)
{
	for (auto t : types) {
		if (str == t.second.name)
			return t.first;
	}

	throw std::invalid_argument("Invalid type");
}

Stats::Stats(int buckets, int warmup)
{
	for (auto m : metrics) {
		histograms.emplace(
			std::piecewise_construct,
          		std::forward_as_tuple(m.first),
          		std::forward_as_tuple(buckets, warmup)
		);
	}
}

void Stats::update(enum Metric m, double val)
{
	histograms[m].put(val);
}

void Stats::reset()
{
	for (auto m : metrics)
		histograms[m.first].reset();
}

json_t * Stats::toJson() const
{
	json_t *obj = json_object();

	for (auto m : metrics) {
		const Hist &h = histograms.at(m.first);

		json_object_set_new(obj, m.second.name, h.toJson());
	}

	return obj;
}

void Stats::printHeader(enum Format fmt)
{
	switch (fmt) {
		case Format::HUMAN:
			setupTable();
			table->header();
			break;

		default: { }
	}
}

void Stats::setupTable()
{
	if (!table)
		table = std::make_shared<Table>(columns);
}

void Stats::printPeriodic(FILE *f, enum Format fmt, struct node *n) const
{
	switch (fmt) {
		case Format::HUMAN:
			setupTable();
			table->row(11,
				node_name_short(n),
				(uintmax_t)    histograms.at(Metric::OWD).getTotal(),
				(uintmax_t)    histograms.at(Metric::AGE).getTotal(),
				(uintmax_t)    histograms.at(Metric::SMPS_REORDERED).getTotal(),
				(uintmax_t)    histograms.at(Metric::SMPS_SKIPPED).getTotal(),
				(double)       histograms.at(Metric::OWD).getLast(),
				(double)       histograms.at(Metric::OWD).getMean(),
				(double) 1.0 / histograms.at(Metric::GAP_RECEIVED).getLast(),
				(double) 1.0 / histograms.at(Metric::GAP_RECEIVED).getMean(),
				(double)       histograms.at(Metric::AGE).getMean(),
				(double)       histograms.at(Metric::AGE).getHighest()
			);
			break;

		case Format::JSON: {
			json_t *json_stats = json_pack("{ s: s, s: i, s: i, s: i, s: i, s: f, s: f, s: f, s: f, s: f, s: f }",
				"node", node_name(n),
				"recv",            histograms.at(Metric::OWD).getTotal(),
				"sent",            histograms.at(Metric::AGE).getTotal(),
				"dropped",         histograms.at(Metric::SMPS_REORDERED).getTotal(),
				"skipped",         histograms.at(Metric::SMPS_SKIPPED).getTotal(),
				"owd_last",  1.0 / histograms.at(Metric::OWD).getLast(),
				"owd_mean",  1.0 / histograms.at(Metric::OWD).getMean(),
				"rate_last", 1.0 / histograms.at(Metric::GAP_SAMPLE).getLast(),
				"rate_mean", 1.0 / histograms.at(Metric::GAP_SAMPLE).getMean(),
				"age_mean",        histograms.at(Metric::AGE).getMean(),
				"age_max",         histograms.at(Metric::AGE).getHighest()
			);
			json_dumpf(json_stats, f, 0);
			break;
		}

		default: { }
	}
}

void Stats::print(FILE *f, enum Format fmt, int verbose) const
{
	switch (fmt) {
		case Format::HUMAN:
			for (auto m : metrics) {
				info("%s: %s", m.second.name, m.second.desc);
				histograms.at(m.first).print(verbose);
			}
			break;

		case Format::JSON:
			json_dumpf(toJson(), f, 0);
			fflush(f);
			break;

		default: { }
	}
}

union signal_data Stats::getValue(enum Metric sm, enum Type st) const
{
	const Hist &h = histograms.at(sm);
	union signal_data d;

	switch (st) {
		case Type::TOTAL:
			d.i = h.getTotal();
			break;

		case Type::LAST:
			d.f = h.getLast();
			break;

		case Type::HIGHEST:
			d.f = h.getHighest();
			break;

		case Type::LOWEST:
			d.f = h.getLowest();
			break;

		case Type::MEAN:
			d.f = h.getMean();
			break;

		case Type::STDDEV:
			d.f = h.getStddev();
			break;

		case Type::VAR:
			d.f = h.getVar();
			break;

		default:
			d.f = -1;
	}

	return d;
}

const Hist & Stats::getHistogram(enum Metric sm) const
{
	return histograms.at(sm);
}

std::shared_ptr<Table> Stats::table = std::shared_ptr<Table>();