/*

 * 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.nio.file.Path;

import java.security.AccessControlContext;

import java.security.AccessController;

import java.time.Duration;

import java.util.Arrays;

import java.util.Comparator;

import java.util.Objects;

import java.util.function.Consumer;

import jdk.jfr.internal.consumer.EventConsumer;

import jdk.jfr.internal.consumer.RecordingInput;

/**

 * Implementation of an event stream that operates against a recording file.

 *

 */

final class EventFileStream implements EventStream {

    private final static class FileEventConsumer extends EventConsumer {

        private static final Comparator<? super RecordedEvent> END_TIME = (e1, e2) -> Long.compare(e1.endTime, e2.endTime);

        private static final int DEFAULT_ARRAY_SIZE = 100_000;

        private final RecordingInput input;

        private ChunkParser chunkParser;

        private boolean reuse = true;

        private RecordedEvent[] sortedList;

        private boolean ordered;

        public FileEventConsumer(AccessControlContext acc, RecordingInput input) throws IOException {

            super(acc);

            this.input = input;

        }

        @Override

        public void process() throws IOException {

            chunkParser = new ChunkParser(input, reuse);

            while (!isClosed()) {

                boolean reuse = this.reuse;

                boolean ordered = this.ordered;

                chunkParser.setReuse(reuse);

                chunkParser.setOrdered(ordered);

                chunkParser.resetEventCache();

                chunkParser.updateEventParsers();

                if (ordered) {

                    processOrdered();

                } else {

                    processUnordered();

                }

                if (chunkParser.isLastChunk()) {

                    return;

                }

                chunkParser = chunkParser.nextChunkParser();

            }

        }

        private void processOrdered() throws IOException {

            if (sortedList == null) {

                sortedList = new RecordedEvent[DEFAULT_ARRAY_SIZE];

            }

            RecordedEvent event;

            int index = 0;

            while (true) {

                event = chunkParser.readEvent();

                if (event == null) {

                    Arrays.sort(sortedList, 0, index, END_TIME);

                    for (int i = 0; i < index; i++) {

                        dispatch(sortedList[i]);

                    }

                    return;

                }

                if (index == sortedList.length) {

                    RecordedEvent[] tmp = sortedList;

                    sortedList = new RecordedEvent[2 * tmp.length];

                    System.arraycopy(tmp, 0, sortedList, 0, tmp.length);

                }

                sortedList[index++] = event;

            }

        }

        private void processUnordered() throws IOException {

            RecordedEvent event;

            while (!isClosed()) {

                event = chunkParser.readEvent();

                if (event == null) {

                    return;

                }

                dispatch(event);

            }

        }

        public void setReuse(boolean reuse) {

            this.reuse = reuse;

        }

        public void setOrdered(boolean ordered) {

            this.ordered = ordered;

        }

        @Override

        public void close() {

        }

    }

    private final RecordingInput input;

    private final FileEventConsumer eventConsumer;

    public EventFileStream(Path path) throws IOException {

        Objects.requireNonNull(path);

        input = new RecordingInput(path.toFile());

        eventConsumer = new FileEventConsumer(AccessController.getContext(), input);

    }

    @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 onFlush(Runnable action) {

        Objects.requireNonNull(action);

        eventConsumer.onFlush(action);

    }

    @Override

    public void onClose(Runnable action) {

        Objects.requireNonNull(action);

        eventConsumer.addCloseAction(action);

    }

    @Override

    public void close() {

        eventConsumer.setClosed(true);

        eventConsumer.runCloseActions();

        try {

            input.close();

        } catch (IOException e) {

            // ignore

        }

    }

    @Override

    public boolean remove(Object action) {

        Objects.requireNonNull(action);

        return eventConsumer.remove(action);

    }

    @Override

    public void start() {

        eventConsumer.start(0);

    }

    public void setReuse(boolean reuse) {

        eventConsumer.setReuse(reuse);

    }

    @Override

    public void startAsync() {

        eventConsumer.startAsync(0);

    }

    @Override

    public void awaitTermination(Duration timeout) {

        Objects.requireNonNull(timeout);

        eventConsumer.awaitTermination(timeout);

    }

    @Override

    public void awaitTermination() {

        eventConsumer.awaitTermination();

    }

    @Override

    public void setOrdered(boolean ordered) {

        eventConsumer.setOrdered(ordered);

    }

}