/*

 * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.jfr.consumer;

import java.io.IOException;

import java.security.AccessControlContext;

import java.time.Duration;

import java.time.Instant;

import java.util.Objects;

import java.util.function.Consumer;

import jdk.jfr.internal.consumer.EventConsumer;

final class EventDirectoryStream implements EventStream {

    private static class EventSetConsumer extends EventConsumer {

        private EventSetLocation location;

        private EventSet eventSet;

        private int eventSetIndex;

        private int eventArrayIndex;

        private RecordedEvent[] currentEventArray = new RecordedEvent[0];

        public EventSetConsumer(AccessControlContext acc) throws IOException {

            super(acc);

        }

        public void process() throws Exception, IOException {

            this.location = EventSetLocation.current();

            this.eventSet = location.acquire(startNanos, null); // use timestamp

                                                                // from

            if (eventSet == null) {

                return;

            }

            while (!isClosed()) {

                processSegment();

                runFlushActions();

                do {

                    if (isClosed()) {

                        return;

                    }

                    currentEventArray = eventSet.readEvents(eventSetIndex);

                    if (currentEventArray == EventSet.END_OF_SET) {

                        eventSet = eventSet.next(eventFilter);

                        if (eventSet == null || isClosed()) {

                            return;

                        }

                        eventSetIndex = 0;

                        continue;

                    }

                    if (currentEventArray == null) {

                        return; // no more events

                    }

                    eventSetIndex++;

                } while (currentEventArray.length == 0);

                eventArrayIndex = 0;

            }

        }

        private void processSegment() {

            while (eventArrayIndex < currentEventArray.length) {

                RecordedEvent e = currentEventArray[eventArrayIndex++];

                if (e == null) {

                    return;

                }

                dispatch(e);

            }

        }

        public void close() {

            setClosed(true);

            // TODO: Data races here, must fix

            synchronized (this) {

                if (eventSet != null) {

                    eventSet.release(null);

                }

                if (location != null) {

                    location.release();

                }

            }

            runCloseActions();

        }

        public void setReuse(boolean reuse) {

            // ignore hint

        }

    }

    private final EventSetConsumer eventConsumer;

    public EventDirectoryStream(AccessControlContext acc) throws IOException {

        eventConsumer = new EventSetConsumer(acc);

    }

    public void close() {

        eventConsumer.close();

    }

    public void onFlush(Runnable action) {

        Objects.requireNonNull(action);

        eventConsumer.onFlush(action);

    }

    void start(long startNanos) {

        eventConsumer.start(startNanos);

    }

    @Override

    public void start() {

        start(Instant.now().toEpochMilli() * 1000 * 1000L);

    }

    @Override

    public void startAsync() {

        startAsync(Instant.now().toEpochMilli() * 1000 * 1000L);

    }

    void startAsync(long startNanos) {

        eventConsumer.startAsync(startNanos);

    }

    @Override

    public void onEvent(Consumer<RecordedEvent> action) {

        Objects.requireNonNull(action);

        eventConsumer.onEvent(action);

    }

    @Override

    public void onEvent(String eventName, Consumer<RecordedEvent> action) {

        Objects.requireNonNull(eventName);

        Objects.requireNonNull(action);

        eventConsumer.onEvent(eventName, action);

    }

    @Override

    public void onClose(Runnable action) {

        Objects.requireNonNull(action);

        eventConsumer.addCloseAction(action);

    }

    @Override

    public boolean remove(Object action) {

        Objects.requireNonNull(action);

        return eventConsumer.remove(action);

    }

    @Override

    public void awaitTermination(Duration timeout) {

        Objects.requireNonNull(timeout);

        eventConsumer.awaitTermination(timeout);

    }

    @Override

    public void awaitTermination() {

        eventConsumer.awaitTermination(Duration.ofMillis(0));

    }

    @Override

    public void setReuse(boolean reuse) {

        eventConsumer.setReuse(reuse);

    }

}