/*

 * 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

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 */

package jdk.jfr.internal.consumer;

import java.io.IOException;

import java.nio.file.Path;

import java.security.AccessControlContext;

import java.util.Arrays;

import java.util.Comparator;

import java.util.Objects;

import jdk.jfr.consumer.RecordedEvent;

import jdk.jfr.internal.consumer.Dispatcher;

import jdk.jfr.internal.consumer.FileAccess;

import jdk.jfr.internal.consumer.RecordingInput;

/**

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

 *

 */

public final class EventFileStream extends AbstractEventStream {

    private final static Comparator<? super RecordedEvent> EVENT_COMPARATOR = JdkJfrConsumer.instance().eventComparator();

    private final RecordingInput input;

    private ChunkParser currentParser;

    private RecordedEvent[] cacheSorted;

    public EventFileStream(AccessControlContext acc, Path path) throws IOException {

        super(acc, false);

        Objects.requireNonNull(path);

        this.input = new RecordingInput(path.toFile(), FileAccess.UNPRIVILIGED);

    }

    @Override

    public void start() {

        start(0);

    }

    @Override

    public void startAsync() {

        startAsync(0);

    }

    @Override

    public void close() {

        setClosed(true);

        dispatcher().runCloseActions();

        try {

            input.close();

        } catch (IOException e) {

            // ignore

        }

    }

    @Override

    protected void process() throws IOException {

        Dispatcher disp = dispatcher();

        long start = 0;

        long end = Long.MAX_VALUE;

        if (disp.startTime != null) {

            start = disp.startNanos;

        }

        if (disp.endTime != null) {

            end = disp.endNanos;

        }

        currentParser = new ChunkParser(input, disp.parserConfiguration);

        while (!isClosed()) {

            if (currentParser.getStartNanos() > end) {

                close();

                return;

            }

            disp = dispatcher();

            disp.parserConfiguration.filterStart = start;

            disp.parserConfiguration.filterEnd = end;

            currentParser.updateConfiguration(disp.parserConfiguration, true);

            currentParser.setFlushOperation(getFlushOperation());

            if (disp.parserConfiguration.isOrdered()) {

                processOrdered(disp);

            } else {

                processUnordered(disp);

            }

            if (isClosed() || currentParser.isLastChunk()) {

                return;

            }

            currentParser = currentParser.nextChunkParser();

        }

    }

    private void processOrdered(Dispatcher c) throws IOException {

        if (cacheSorted == null) {

            cacheSorted = new RecordedEvent[10_000];

        }

        RecordedEvent event;

        int index = 0;

        while (true) {

            event = currentParser.readEvent();

            if (event == null) {

                Arrays.sort(cacheSorted, 0, index, EVENT_COMPARATOR);

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

                    c.dispatch(cacheSorted[i]);

                }

                return;

            }

            if (index == cacheSorted.length) {

                RecordedEvent[] tmp = cacheSorted;

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

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

            }

            cacheSorted[index++] = event;

        }

    }

    private void processUnordered(Dispatcher c) throws IOException {

        while (!isClosed()) {

            RecordedEvent event = currentParser.readEvent();

            if (event == null) {

                return;

            }

            c.dispatch(event);

        }

    }

}