import java.net.URI;
import java.net.http.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.concurrent.atomic.*;

/** Closed-loop load: THREADS threads, WARMUP seconds discarded, then MEASURE seconds recorded. */
public class Load {
    public static void main(String[] a) throws Exception {
        int port = Integer.parseInt(a[0]), warmup = Integer.parseInt(a[1]), measure = Integer.parseInt(a[2]), threads = Integer.parseInt(a[3]);
        HttpClient c = HttpClient.newBuilder().version(HttpClient.Version.HTTP_1_1).build();
        HttpRequest rq = HttpRequest.newBuilder(URI.create("http://localhost:" + port + "/quote?n=200")).build();
        long start = System.nanoTime();
        long measureFrom = start + warmup * 1_000_000_000L, end = measureFrom + measure * 1_000_000_000L;
        List<long[]> perThread = new CopyOnWriteArrayList<>();
        ExecutorService ex = Executors.newFixedThreadPool(threads);
        List<Future<?>> fs = new ArrayList<>();
        for (int t = 0; t < threads; t++) fs.add(ex.submit(() -> {
            long[] buf = new long[2_000_000]; int n = 0;
            try {
                while (true) {
                    long s = System.nanoTime();
                    if (s >= end) break;
                    c.send(rq, HttpResponse.BodyHandlers.discarding());
                    long e = System.nanoTime();
                    if (s >= measureFrom && n < buf.length) buf[n++] = e - s;
                }
            } catch (Exception e) { throw new RuntimeException(e); }
            perThread.add(Arrays.copyOf(buf, n));
            return null;
        }));
        for (Future<?> f : fs) f.get();
        ex.shutdown();
        long total = 0; for (long[] b : perThread) total += b.length;
        long[] all = new long[(int) total]; int p = 0;
        for (long[] b : perThread) { System.arraycopy(b, 0, all, p, b.length); p += b.length; }
        Arrays.sort(all);
        System.out.printf("requests=%d throughput=%.0f req/s p50=%.2f ms p99=%.2f ms p99.9=%.2f ms max=%.2f ms%n",
            total, total / (double) measure, all[(int) (total * 0.50)] / 1e6, all[(int) (total * 0.99)] / 1e6,
            all[(int) (total * 0.999)] / 1e6, all[(int) total - 1] / 1e6);
    }
}