package com.ankurm.protocols;

import java.util.Arrays;

/** Latency bookkeeping, kept in one place so the three protocols are measured identically. */
final class Bench {

    private final long[] nanos;
    private int i;

    Bench(int n) {
        this.nanos = new long[n];
    }

    void record(long ns) {
        nanos[i++] = ns;
    }

    /** p50, p99 and mean in microseconds, plus calls per second derived from the mean. */
    String summary(String label) {
        long[] sorted = Arrays.copyOf(nanos, i);
        Arrays.sort(sorted);
        double p50 = sorted[(int) (sorted.length * 0.50)] / 1000.0;
        double p99 = sorted[(int) (sorted.length * 0.99)] / 1000.0;
        double mean = Arrays.stream(sorted).average().orElse(0) / 1000.0;
        return String.format("%-12s n=%-6d p50=%8.1f us  p99=%9.1f us  mean=%8.1f us  ~%,.0f calls/s",
                label, sorted.length, p50, p99, mean, 1_000_000.0 / mean);
    }
}