package net.minecraft.util.profiling.jfr.stats;

import java.time.Duration;
import java.util.Comparator;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import net.minecraft.util.profiling.jfr.Percentiles;
import org.jspecify.annotations.Nullable;

public record TimedStatSummary<T extends TimedStat>(
	T fastest, T slowest, @Nullable T secondSlowest, int count, Map<Integer, Double> percentilesNanos, Duration totalDuration
) {
	public static <T extends TimedStat> Optional<TimedStatSummary<T>> summary(final List<T> values) {
		if (values.isEmpty()) {
			return Optional.empty();
		} else {
			List<T> sorted = values.stream().sorted(Comparator.comparing(TimedStat::duration)).toList();
			Duration totalDuration = (Duration)sorted.stream().map(TimedStat::duration).reduce(Duration::plus).orElse(Duration.ZERO);
			T fastest = (T)sorted.getFirst();
			T slowest = (T)sorted.getLast();
			T secondSlowest = (T)(sorted.size() > 1 ? sorted.get(sorted.size() - 2) : null);
			int count = sorted.size();
			Map<Integer, Double> percentilesNanos = Percentiles.evaluate(sorted.stream().mapToLong(it -> it.duration().toNanos()).toArray());
			return Optional.of(new TimedStatSummary(fastest, slowest, secondSlowest, count, percentilesNanos, totalDuration));
		}
	}
}