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package jdk.jfr.event.oldobject;

import java.time.Instant;

import java.util.List;

import jdk.jfr.Event;

import jdk.jfr.Recording;

import jdk.jfr.consumer.RecordedClass;

import jdk.jfr.consumer.RecordedClassLoader;

import jdk.jfr.consumer.RecordedEvent;

import jdk.jfr.consumer.RecordedFrame;

import jdk.jfr.consumer.RecordedStackTrace;

import jdk.jfr.consumer.RecordedThread;

import jdk.jfr.internal.test.WhiteBox;

import jdk.test.lib.Asserts;

import jdk.test.lib.jfr.EventNames;

import jdk.test.lib.jfr.Events;

import jdk.test.lib.jfr.TestClassLoader;

/**

 * @test

 * @summary The test verifies that an old object sample maintains references to "stale" metadata

 * @requires vm.hasJFR

 * @requires vm.gc == "null"

 * @key jfr

 * @modules jdk.jfr/jdk.jfr.internal.test

 * @library /test/lib /test/jdk

 * @build jdk.jfr.event.oldobject.TestMetadataObject

 * @run main/othervm -XX:TLABSize=2k -Xmx16m jdk.jfr.event.oldobject.TestMetadataRetention

 */

public final class TestMetadataRetention {

    private final static String TEST_PACKAGE = TestMetadataRetention.class.getPackage().getName();

    private final static String TEST_CLASS_LOADER_NAME = "JFR TestClassLoader";

    private final static String TEST_CLASS_NAME = TEST_PACKAGE + ".TestMetadataObject";

    private final static String ALLOCATOR_THREAD_NAME = "TestAllocationThread";

    public static ClassLoader testClassLoader;

    public static Object leakObject;

    public static Thread allocatorThread;

    public static Class<?> testClass;

    static class ChunkRotation extends Event {

    }

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

        WhiteBox.setWriteAllObjectSamples(true);

        while (true) {

            int failedAttempts = 0;

            try (Recording recording = new Recording()) {

                recording.enable(EventNames.OldObjectSample).withStackTrace();

                recording.enable(EventNames.ClassUnload);

                recording.start();

                // Setup metadata on the Java heap (class, stack trace and thread)

                testClassLoader = new TestClassLoader();

                testClass = testClassLoader.loadClass(TEST_CLASS_NAME);

                allocatorThread = new Thread(TestMetadataRetention::allocateLeak, ALLOCATOR_THREAD_NAME);

                allocatorThread.start();

                allocatorThread.join();

                // Clear out metadata on the heap

                testClassLoader = null;

                testClass = null;

                allocatorThread = null;

                // System.gc() will trigger class unloading if -XX:+ExplicitGCInvokesConcurrent

                // outside it should be enough with System.gc().

                System.gc();

                // Provoke a chunk rotation, which will flush out ordinary metadata.

                provokeChunkRotation();

                ChunkRotation cr = new ChunkRotation();

                cr.commit();

                recording.stop();

                List<RecordedEvent> events = Events.fromRecording(recording);

                RecordedEvent chunkRotation = findChunkRotationEvent(events);

                try {

                    // Sanity check that class was unloaded

                    Events.hasEvent(recording, EventNames.ClassUnload);

                    validateClassUnloadEvent(events);

                    // Validate that metadata for old object event has survived chunk rotation

                    Events.hasEvent(recording, EventNames.OldObjectSample);

                    validateOldObjectEvent(events, chunkRotation.getStartTime());

                } catch (Throwable t) {

                    t.printStackTrace();

                    System.out.println("Number of failed attempts " + ++failedAttempts);

                    continue;

                }

                break;

            }

        }

    }

    private static RecordedEvent findChunkRotationEvent(List<RecordedEvent> events) {

        for (RecordedEvent e : events)  {

            if (e.getEventType().getName().equals(ChunkRotation.class.getName())) {

                return e;

            }

        }

        Asserts.fail("Could not find chunk rotation event");

        return null; // Can't happen;

    }

    private static void allocateLeak() {

        try {

            leakObject = testClass.getMethod("startRecurse").invoke(null);

        } catch (Exception e) {

            System.out.println("Could not allocate memory leak!");

            e.printStackTrace();

        }

    }

    private static void provokeChunkRotation() {

        try (Recording r = new Recording()) {

            r.start();

            r.stop();

        }

    }

    private static void validateClassUnloadEvent(List<RecordedEvent> events) throws Throwable {

        for (RecordedEvent event : events) {

            if (event.getEventType().getName().equals(EventNames.ClassUnload)) {

                RecordedClass unloadedClass = event.getValue("unloadedClass");

                if (TEST_CLASS_NAME.equals(unloadedClass.getName())) {

                    RecordedClassLoader definingClassLoader = unloadedClass.getClassLoader();

                    Asserts.assertEquals(TEST_CLASS_LOADER_NAME, definingClassLoader.getName(), "Expected " + TEST_CLASS_LOADER_NAME + ", got " + definingClassLoader.getType().getName());

                    return;

                }

            }

        }

    }

    private static void validateOldObjectEvent(List<RecordedEvent> events, Instant chunkRotation) throws Throwable {

        for (RecordedEvent event : events) {

            if (event.getEventType().getName().equals(EventNames.OldObjectSample)) {

                // Only check event after the rotation

                if (!event.getStartTime().isBefore(chunkRotation)) {

                    System.out.println(event);

                    RecordedThread rt = event.getThread();

                    if (rt.getJavaName().equals(ALLOCATOR_THREAD_NAME)) {

                        RecordedStackTrace s = event.getStackTrace();

                        assertStackTrace(s, "startRecurse");

                        assertStackTrace(s, "recurse");

                        return;

                    }

                }

            }

        }

        Asserts.fail("Did not find an old object event with thread " + ALLOCATOR_THREAD_NAME);

    }

    private static void assertStackTrace(RecordedStackTrace stacktrace, final String methodName) {

        for (RecordedFrame f : stacktrace.getFrames()) {

            if (f.getMethod().getName().equals(methodName)) {

                return;

            }

        }

        Asserts.fail("Could not find class " + methodName + " in stack trace " + stacktrace);

    }

}