/*

 * 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.consumer;

import java.io.IOException;

import java.security.AccessControlContext;

import java.security.AccessController;

import java.time.Duration;

import java.time.Instant;

import java.util.Map;

import java.util.function.Consumer;

import jdk.jfr.Configuration;

import jdk.jfr.Event;

import jdk.jfr.EventSettings;

import jdk.jfr.EventType;

import jdk.jfr.Recording;

import jdk.jfr.internal.PlatformRecording;

import jdk.jfr.internal.PrivateAccess;

import jdk.jfr.internal.Utils;

/**

 * A recording stream produces events from the current JVM (Java Virtual

 * Machine).

 * <p>

 * The following example records events using the default configuration and

 * prints the Garbage Collection, CPU Load and JVM Information event.

 *

 * <pre>

 * <code>

 * var c = Configuration.getConfiguration("default");

 * try (var rs = new RecordingStream(c)) {

 *     rs.onEvent("jdk.GarbageCollection", System.out::println);

 *     rs.onEvent("jdk.CPULoad", System.out::println);

 *     rs.onEvent("jdk.JVMInformation", System.out::println);

 *     rs.start();

 *   }

 * }

 * </code>

 * </pre>

 *

 */

public final class RecordingStream implements AutoCloseable, EventStream {

    private final Recording recording;

    private final EventDirectoryStream stream;

    /**

     * Creates an event stream for the current JVM (Java Virtual Machine).

     * <p>

     * The following example shows how to create a recording stream that prints

     * CPU usage and information about garbage collections.

     *

     * <pre>

     * <code>

     * try (var rs = new RecordingStream()) {

     *   rs.enable("jdk.GarbageCollection");

     *   rs.enable("jdk.CPULoad").withPeriod(Duration.ofSeconds(1));

     *   rs.onEvent(System.out::println);

     *   rs.start();

     * }

     * </code>

     * </pre>

     *

     * @throws IllegalStateException if Flight Recorder can't be created (for

     *         example, if the Java Virtual Machine (JVM) lacks Flight Recorder

     *         support, or if the file repository can't be created or accessed)

     *

     * @throws SecurityException if a security manager exists and the caller

     *         does not have

     *         {@code FlightRecorderPermission("accessFlightRecorder")}

     */

    public RecordingStream() {

        Utils.checkAccessFlightRecorder();

        AccessControlContext acc = AccessController.getContext();

        this.recording = new Recording();

        this.recording.setFlushInterval(Duration.ofMillis(1000));

        try {

        } catch (IOException ioe) {

            throw new IllegalStateException(ioe.getMessage());

        }

    }

    /**

     * Creates a recording stream using settings from a configuration.

     * <p>

     * The following example shows how to create a recording stream that uses a

     * predefined configuration.

     *

     * <pre>

     * <code>

     * var c = Configuration.getConfiguration("default");

     * try (RecordingStream rs = new RecordingStream(c)) {

     *   rs.onEvent(System.out::println);

     *   rs.start();

     * }

     * </code>

     * </pre>

     *

     * @param configuration configuration that contains the settings to be use,

     *        not {@code null}

     *

     * @throws IllegalStateException if Flight Recorder can't be created (for

     *         example, if the Java Virtual Machine (JVM) lacks Flight Recorder

     *         support, or if the file repository can't be created or accessed)

     *

     * @throws SecurityException if a security manager is used and

     *         FlightRecorderPermission "accessFlightRecorder" is not set.

     *

     * @see Configuration

     */

    public RecordingStream(Configuration configuration) {

        this();

        recording.setSettings(configuration.getSettings());

    }

    /**

     * Enables the event with the specified name.

     * <p>

     * If multiple events have the same name (for example, the same class is

     * loaded in different class loaders), then all events that match the name

     * are enabled. To enable a specific class, use the {@link #enable(Class)}

     * method or a {@code String} representation of the event type ID.

     *

     * @param name the settings for the event, not {@code null}

     *

     * @return an event setting for further configuration, not {@code null}

     *

     * @see EventType

     */

    public EventSettings enable(String name) {

        return recording.enable(name);

    }

    /**

     * Replaces all settings for this recording stream

     * <p>

     * The following example records 20 second using the "default" configuration

     * and then changes to settings for the "profile" configuration.

     *

     * <pre>

     * <code>

     *     var defaultConfiguration = Configuration.getConfiguration("default");

     *     var profileConfiguration = Configuration.getConfiguration("profile");

     *     try (var rs = new RecordingStream(defaultConfiguration) {

     *        rs.startAsync();

     *        Thread.sleep(20_000);

     *        rs.setSettings(profileConfiguration.getSettings());

     *        Thread.sleep(20_000);

     *     }

     * </code>

     * </pre>

     *

     * @param settings the settings to set, not {@code null}

     */

    public void setSettings(Map<String, String> settings) {

        recording.setSettings(settings);

    };

    /**

     * Enables event.

     *

     * @param eventClass the event to enable, not {@code null}

     *

     * @throws IllegalArgumentException if {@code eventClass} is an abstract

     *         class or not a subclass of {@link Event}

     *

     * @return an event setting for further configuration, not {@code null}

     */

    public EventSettings enable(Class<? extends Event> eventClass) {

        return recording.enable(eventClass);

    }

    /**

     * Disables event with the specified name.

     * <p>

     * If multiple events with same name (for example, the same class is loaded

     * in different class loaders), then all events that match the name is

     * disabled. To disable a specific class, use the {@link #disable(Class)}

     * method or a {@code String} representation of the event type ID.

     *

     * @param name the settings for the event, not {@code null}

     *

     * @return an event setting for further configuration, not {@code null}

     *

     */

    public EventSettings disable(String name) {

        return recording.disable(name);

    }

    /**

     * Disables event.

     *

     * @param eventClass the event to enable, not {@code null}

     *

     * @throws IllegalArgumentException if {@code eventClass} is an abstract

     *         class or not a subclass of {@link Event}

     *

     * @return an event setting for further configuration, not {@code null}

     *

     */

    public EventSettings disable(Class<? extends Event> eventClass) {

        return recording.disable(eventClass);

    }

    /**

     * Determines how far back data is kept for the stream, if the stream can't

     * keep up.

     * <p>

     * To control the amount of recording data stored on disk, the maximum

     * length of time to retain the data can be specified. Data stored on disk

     * that is older than the specified length of time is removed by the Java

     * Virtual Machine (JVM).

     * <p>

     * If neither maximum limit or the maximum age is set, the size of the

     * recording may grow indefinitely if events are on

     *

     * @param maxAge the length of time that data is kept, or {@code null} if

     *        infinite

     *

     * @throws IllegalArgumentException if <code>maxAge</code> is negative

     *

     * @throws IllegalStateException if the recording is in the {@code CLOSED}

     *         state

     */

    public void setMaxAge(Duration maxAge) {

        recording.setMaxAge(maxAge);

    }

    /**

     * Determines how much data is kept in the disk repository if the stream

     * can't keep up.

     * <p>

     * To control the amount of recording data that is stored on disk, the

     * maximum amount of data to retain can be specified. When the maximum limit

     * is exceeded, the Java Virtual Machine (JVM) removes the oldest chunk to

     * make room for a more recent chunk.

     * <p>

     * If neither maximum limit or the maximum age is set, the size of the

     * recording may grow indefinitely.

     *

     * @param maxSize the amount of data to retain, {@code 0} if infinite

     *

     * @throws IllegalArgumentException if <code>maxSize</code> is negative

     *

     * @throws IllegalStateException if the recording is in {@code CLOSED} state

     */

    public void setMaxSize(long maxSize) {

        recording.setMaxSize(maxSize);

    }

    @Override

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

        stream.onEvent(eventName, action);

    }

    @Override

    public void onEvent(Consumer<RecordedEvent> action) {

        stream.onEvent(action);

    }

    @Override

    public void onFlush(Runnable action) {

        stream.onFlush(action);

    }

    @Override

    public void onClose(Runnable action) {

        stream.onClose(action);

    }

    @Override

    public void close() {

        recording.close();

        stream.close();

    }

    @Override

    public boolean remove(Object action) {

        return stream.remove(action);

    }

    @Override

    public void start() {

        PlatformRecording pr = PrivateAccess.getInstance().getPlatformRecording(recording);

        long startNanos = pr.start();

        stream.start(startNanos);

    }

    @Override

    public void startAsync() {

        PlatformRecording pr = PrivateAccess.getInstance().getPlatformRecording(recording);

        long startNanos = pr.start();

        stream.startAsync(startNanos);

    }

    @Override

    public void awaitTermination(Duration timeout) {

        stream.awaitTermination(timeout);

    }

    /**

     * Determines how often events are made available for streaming.

     *

     * @param interval the interval at which events are made available to the

     *        stream, no {@code null}

     *

     * @throws IllegalArgumentException if <code>interval</code> is negative

     *

     * @throws IllegalStateException if the stream is closed

     */

    public void setInterval(Duration duration) {

        recording.setFlushInterval(duration);

    }

    @Override

    public void awaitTermination() {

        stream.awaitTermination();

    }

    @Override

    public void setReuse(boolean reuse) {

        stream.setReuse(reuse);

    }

    @Override

    public void setOrdered(boolean ordered) {

        stream.setOrdered(ordered);

    }

    @Override

    public void setStartTime(Instant startTime) {

        stream.setStartTime(startTime);

    }

    @Override

    public void setEndTime(Instant endTime) {

        stream.setStartTime(endTime);

    }

}