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package jdk.jfr.api.event;

import java.time.Duration;

import jdk.jfr.Event;

import jdk.jfr.Recording;

import jdk.test.lib.Asserts;

 * @test

 * @summary Test enable/disable event and verify recording has expected events.

 * @key jfr

 * @library /test/lib

 * @run main/othervm -Xlog:jfr+event+setting=trace jdk.jfr.api.event.TestShouldCommit

 */

public class TestShouldCommit {

    public static void main(String[] args) throws Exception {

        Recording rA = new Recording();

        verifyShouldCommitFalse(); // No active recordings

        rA.start();

        rA.enable(MyEvent.class).withoutThreshold(); // recA=all

        verifyShouldCommitTrue();

        setThreshold(rA, 100); // recA=100

        verifyThreshold(100);

        setThreshold(rA, 200); // recA=200

        verifyThreshold(200);

        Recording rB = new Recording();

        verifyThreshold(200);  // recA=200, recB=not started

        rB.start();

        verifyThreshold(200);  // recA=200, recB=not specified, settings from recA is used.

        setThreshold(rB, 100); // recA=200, recB=100

        verifyThreshold(100);

        setThreshold(rB, 300); // recA=200, recB=300

        verifyThreshold(200);

        rA.disable(MyEvent.class); // recA=disabled, recB=300

        verifyThreshold(300);

        rB.disable(MyEvent.class); // recA=disabled, recB=disabled

        verifyShouldCommitFalse();

        setThreshold(rA, 200); // recA=200, recB=disabled

        verifyThreshold(200);

        rB.enable(MyEvent.class).withoutThreshold(); // recA=200, recB=all

        verifyShouldCommitTrue();

        setThreshold(rB, 100); // recA=200, recB=100

        verifyThreshold(100);

        rB.stop(); // recA=200, recB=stopped

        verifyThreshold(200);

        rA.stop(); // recA=stopped, recB=stopped

        verifyShouldCommitFalse();

        rA.close();

        rB.close();

        verifyShouldCommitFalse();

    }

    private static void setThreshold(Recording r, long millis) {

        r.enable(MyEvent.class).withThreshold(Duration.ofMillis(millis));

    }

    private static void verifyThreshold(long threshold) throws Exception {

        // Create 2 events, with different sleep time between begin() and end()

        // First event ends just before threshold, the other just after.

        verifyThreshold(threshold-5, threshold);

        verifyThreshold(threshold+5, threshold);

    }

    private static void verifyThreshold(long sleepMs, long thresholdMs) throws Exception {

        MyEvent event = new MyEvent();

        long beforeStartNanos = System.nanoTime();

        event.begin();

        long afterStartNanos = System.nanoTime();

        Thread.sleep(sleepMs);

        long beforeStopNanos = System.nanoTime();

        event.end();

        long afterStopNanos = System.nanoTime();

        boolean actualShouldCommit = event.shouldCommit();

        final long safetyMarginNanos = 2000000; // Allow an error of 2 ms. May have to be tuned.

        //Duration of event has been at least minDurationMicros

        long minDurationMicros = (beforeStopNanos - afterStartNanos - safetyMarginNanos) / 1000;

        //Duration of event has been at most maxDurationMicros

        long maxDurationMicros = (afterStopNanos - beforeStartNanos + safetyMarginNanos) / 1000;

        Asserts.assertLessThanOrEqual(minDurationMicros, maxDurationMicros, "Wrong min/max duration. Test error.");

        long thresholdMicros = thresholdMs * 1000;

        Boolean shouldCommit = null;

        if (minDurationMicros > thresholdMicros) {

            shouldCommit = new Boolean(true);  // shouldCommit() must be true

        } else if (maxDurationMicros < thresholdMicros) {

            shouldCommit = new Boolean(false); // shouldCommit() must be false

        } else {

            // Too close to call. No checks are done since we are not sure of expected shouldCommit().

        }

        System.out.printf(

            "threshold=%d, duration=[%d-%d], shouldCommit()=%b, expected=%s%n",

            thresholdMicros, minDurationMicros, maxDurationMicros, actualShouldCommit,

            (shouldCommit!=null ? shouldCommit : "too close to call"));

        try {

            if (shouldCommit != null) {

                Asserts.assertEquals(shouldCommit.booleanValue(), actualShouldCommit, "Wrong shouldCommit()");

            }

        } catch (Exception e) {

            System.out.println("Unexpected value of shouldCommit(). Searching for active threshold...");

            searchThreshold(thresholdMs, 2000+thresholdMs);

            throw e;

        }

    }

    // Sleeps until shouldCommit() is true, or give up. Used for logging.

    private static void searchThreshold(long expectedMs, long maxMs) throws Exception {

        long start = System.nanoTime();

        long stop = start + maxMs * 1000000;

        MyEvent event = new MyEvent();

        event.begin();

        event.end();

        while (!event.shouldCommit() && System.nanoTime() < stop) {

            Thread.sleep(1);

            event.end();

        }

        long durationMicros = (System.nanoTime() - start) / 1000;

        long expectedMicros = expectedMs * 1000;

        System.out.printf("shouldCommit()=%b after %,d ms, expected %,d%n", event.shouldCommit(), durationMicros, expectedMicros);

    }

    private static void verifyShouldCommitFalse() {

        MyEvent event = new MyEvent();

        event.begin();

        event.end();

        Asserts.assertFalse(event.shouldCommit(), "shouldCommit() expected false");

    }

    private static void verifyShouldCommitTrue() {

        MyEvent event = new MyEvent();

        event.begin();

        event.end();

        Asserts.assertTrue(event.shouldCommit(), "shouldCommit() expected true");

    }

    private static class MyEvent extends Event {

    }

}