/*

 * Copyright (c) 2016, 2018, 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.management.jfr;

import java.io.IOException;

import java.io.InputStream;

import java.io.StringReader;

import java.nio.file.Paths;

import java.security.AccessControlContext;

import java.security.AccessController;

import java.security.PrivilegedAction;

import java.text.ParseException;

import java.time.Instant;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collections;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import java.util.Objects;

import java.util.concurrent.ConcurrentHashMap;

import java.util.concurrent.CopyOnWriteArrayList;

import java.util.concurrent.atomic.AtomicLong;

import java.util.function.Consumer;

import java.util.function.Function;

import java.util.function.Predicate;

import javax.management.AttributeChangeNotification;

import javax.management.AttributeNotFoundException;

import javax.management.ListenerNotFoundException;

import javax.management.MBeanException;

import javax.management.MBeanNotificationInfo;

import javax.management.Notification;

import javax.management.NotificationBroadcasterSupport;

import javax.management.NotificationEmitter;

import javax.management.NotificationFilter;

import javax.management.NotificationListener;

import javax.management.ObjectName;

import javax.management.ReflectionException;

import javax.management.StandardEmitterMBean;

import jdk.jfr.Configuration;

import jdk.jfr.EventType;

import jdk.jfr.FlightRecorder;

import jdk.jfr.FlightRecorderListener;

import jdk.jfr.FlightRecorderPermission;

import jdk.jfr.Recording;

import jdk.jfr.RecordingState;

import jdk.jfr.internal.management.ManagementSupport;

// Instantiated by service provider

final class FlightRecorderMXBeanImpl extends StandardEmitterMBean implements FlightRecorderMXBean, NotificationEmitter {

    final class MXBeanListener implements FlightRecorderListener {

        private final NotificationListener listener;

        private final NotificationFilter filter;

        private final Object handback;

        private final AccessControlContext context;

        public MXBeanListener(NotificationListener listener, NotificationFilter filter, Object handback) {

            this.context = AccessController.getContext();

            this.listener = listener;

            this.filter = filter;

            this.handback = handback;

        }

        public void recordingStateChanged(Recording recording) {

            AccessController.doPrivileged(new PrivilegedAction<Void>() {

                @Override

                public Void run() {

                    sendNotification(createNotication(recording));

                    return null;

                }

            }, context);

        }

    }

    private static final String ATTRIBUTE_RECORDINGS = "Recordings";

    private static final String OPTION_MAX_SIZE = "maxSize";

    private static final String OPTION_MAX_AGE = "maxAge";

    private static final String OPTION_NAME = "name";

    private static final String OPTION_DISK = "disk";

    private static final String OPTION_DUMP_ON_EXIT = "dumpOnExit";

    private static final String OPTION_DURATION = "duration";

    private final StreamManager streamHandler = new StreamManager();

    private final Map<Long, Object> changes = new ConcurrentHashMap<>();

    private final AtomicLong sequenceNumber = new AtomicLong();

    private final List<MXBeanListener> listeners = new CopyOnWriteArrayList<>();

    private FlightRecorder recorder;

    FlightRecorderMXBeanImpl() {

        super(FlightRecorderMXBean.class, true, new NotificationBroadcasterSupport(createNotificationInfo()));

    }

    @Override

    public void startRecording(long id) {

        MBeanUtils.checkControl();

        getExistingRecording(id).start();

    }

    @Override

    public boolean stopRecording(long id) {

        MBeanUtils.checkControl();

        return getExistingRecording(id).stop();

    }

    @Override

    public void closeRecording(long id) {

        MBeanUtils.checkControl();

        getExistingRecording(id).close();

    }

    @Override

    public long openStream(long id, Map<String, String> options) throws IOException {

        MBeanUtils.checkControl();

        if (!FlightRecorder.isInitialized()) {

            throw new IllegalArgumentException("No recording available with id " + id);

        }

        // Make local copy to prevent concurrent modification

        Map<String, String> s = options == null ? new HashMap<>() : new HashMap<>(options);

        Instant starttime = MBeanUtils.parseTimestamp(s.get("startTime"), Instant.MIN);

        Instant endtime = MBeanUtils.parseTimestamp(s.get("endTime"), Instant.MAX);

        int blockSize = MBeanUtils.parseBlockSize(s.get("blockSize"), StreamManager.DEFAULT_BLOCK_SIZE);

        InputStream is = getExistingRecording(id).getStream(starttime, endtime);

        if (is == null) {

            throw new IOException("No recording data available");

        }

        return streamHandler.create(is, blockSize).getId();

    }

    @Override

    public void closeStream(long streamIdentifier) throws IOException {

        MBeanUtils.checkControl();

        streamHandler.getStream(streamIdentifier).close();

    }

    @Override

    public byte[] readStream(long streamIdentifier) throws IOException {

        MBeanUtils.checkMonitor();

        return streamHandler.getStream(streamIdentifier).read();

    }

    @Override

    public List<RecordingInfo> getRecordings() {

        MBeanUtils.checkMonitor();

        if (!FlightRecorder.isInitialized()) {

            return Collections.emptyList();

        }

        return MBeanUtils.transformList(getRecorder().getRecordings(), RecordingInfo::new);

    }

    @Override

    public List<ConfigurationInfo> getConfigurations() {

        MBeanUtils.checkMonitor();

        return MBeanUtils.transformList(Configuration.getConfigurations(), ConfigurationInfo::new);

    }

    @Override

    public List<EventTypeInfo> getEventTypes() {

        MBeanUtils.checkMonitor();

        List<EventType> eventTypes = AccessController.doPrivileged(new PrivilegedAction<List<EventType>>() {

            @Override

            public List<EventType> run() {

                return ManagementSupport.getEventTypes();

            }

        }, null, new FlightRecorderPermission("accessFlightRecorder"));

        return MBeanUtils.transformList(eventTypes, EventTypeInfo::new);

    }

    @Override

    public Map<String, String> getRecordingSettings(long recording) throws IllegalArgumentException {

        MBeanUtils.checkMonitor();

        return getExistingRecording(recording).getSettings();

    }

    @Override

    public void setRecordingSettings(long recording, Map<String, String> values) throws IllegalArgumentException {

        Objects.requireNonNull(values);

        MBeanUtils.checkControl();

        getExistingRecording(recording).setSettings(values);

    }

    @Override

    public long newRecording() {

        MBeanUtils.checkControl();

        getRecorder(); // ensure notification listener is setup

        return AccessController.doPrivileged(new PrivilegedAction<Recording>() {

            @Override

            public Recording run() {

                return new Recording();

            }

        }, null, new FlightRecorderPermission("accessFlightRecorder")).getId();

    }

    @Override

    public long takeSnapshot() {

        MBeanUtils.checkControl();

        return getRecorder().takeSnapshot().getId();

    }

    @Override

    public void setConfiguration(long recording, String configuration) throws IllegalArgumentException {

        Objects.requireNonNull(configuration);

        MBeanUtils.checkControl();

        try {

            Configuration c = Configuration.create(new StringReader(configuration));

            getExistingRecording(recording).setSettings(c.getSettings());

        } catch (IOException | ParseException e) {

            throw new IllegalArgumentException("Could not parse configuration", e);

        }

    }

    @Override

    public void setPredefinedConfiguration(long recording, String configurationName) throws IllegalArgumentException {

        Objects.requireNonNull(configurationName);

        MBeanUtils.checkControl();

        Recording r = getExistingRecording(recording);

        for (Configuration c : Configuration.getConfigurations()) {

            if (c.getName().equals(configurationName)) {

                r.setSettings(c.getSettings());

                return;

            }

        }

        throw new IllegalArgumentException("Could not find configuration with name " + configurationName);

    }

    @Override

    public void copyTo(long recording, String path) throws IOException {

        Objects.requireNonNull(path);

        MBeanUtils.checkControl();

        getExistingRecording(recording).dump(Paths.get(path));

    }

    @Override

    public void setRecordingOptions(long recording, Map<String, String> options) throws IllegalArgumentException {

        Objects.requireNonNull(options);

        MBeanUtils.checkControl();

        // Make local copy to prevent concurrent modification

        Map<String, String> ops = new HashMap<String, String>(options);

        for (Map.Entry<String, String> entry : ops.entrySet()) {

            Object key = entry.getKey();

            Object value = entry.getValue();

            if (!(key instanceof String)) {

                throw new IllegalArgumentException("Option key must not be null, or other type than " + String.class);

            }

            if (!OPTIONS.contains(key)) {

                throw new IllegalArgumentException("Unknown recording option: " + key + ". Valid options are " + OPTIONS + ".");

            }

            if (value != null && !(value instanceof String)) {

                throw new IllegalArgumentException("Incorrect value for option " + key + ". Values must be of type " + String.class + " .");

            }

        }

        Recording r = getExistingRecording(recording);

        validateOption(ops, OPTION_DUMP_ON_EXIT, MBeanUtils::booleanValue);

        validateOption(ops, OPTION_DISK, MBeanUtils::booleanValue);

        validateOption(ops, OPTION_NAME, Function.identity());

        validateOption(ops, OPTION_MAX_AGE, MBeanUtils::duration);

        validateOption(ops, OPTION_MAX_SIZE, MBeanUtils::size);

        validateOption(ops, OPTION_DURATION, MBeanUtils::duration);

        // All OK, now set them.atomically

        setOption(ops, OPTION_DUMP_ON_EXIT, "false", MBeanUtils::booleanValue, x -> r.setDumpOnExit(x));

        setOption(ops, OPTION_DISK, "true", MBeanUtils::booleanValue, x -> r.setToDisk(x));

        setOption(ops, OPTION_NAME, String.valueOf(r.getId()), Function.identity(), x -> r.setName(x));

        setOption(ops, OPTION_MAX_AGE, null, MBeanUtils::duration, x -> r.setMaxAge(x));

        setOption(ops, OPTION_MAX_SIZE, "0", MBeanUtils::size, x -> r.setMaxSize(x));

        setOption(ops, OPTION_DURATION, null, MBeanUtils::duration, x -> r.setDuration(x));

    }

    @Override

    public Map<String, String> getRecordingOptions(long recording) throws IllegalArgumentException {

        MBeanUtils.checkMonitor();

        Recording r = getExistingRecording(recording);

        Map<String, String> options = new HashMap<>(10);

        options.put(OPTION_DUMP_ON_EXIT, String.valueOf(r.getDumpOnExit()));

        options.put(OPTION_DISK, String.valueOf(r.isToDisk()));

        options.put(OPTION_NAME, String.valueOf(r.getName()));

        options.put(OPTION_MAX_AGE, ManagementSupport.formatTimespan(r.getMaxAge(), " "));

        Long maxSize = r.getMaxSize();

        options.put(OPTION_MAX_SIZE, String.valueOf(maxSize == null ? "0" : maxSize.toString()));

        options.put(OPTION_DURATION, ManagementSupport.formatTimespan(r.getDuration(), " "));

        return options;

    }

    @Override

    public long cloneRecording(long id, boolean stop) throws IllegalStateException, SecurityException {

        MBeanUtils.checkControl();

        return getRecording(id).copy(stop).getId();

    }

    @Override

    public ObjectName getObjectName() {

        return MBeanUtils.createObjectName();

    }

    private Recording getExistingRecording(long id) {

        if (FlightRecorder.isInitialized()) {

            Recording recording = getRecording(id);

            if (recording != null) {

                return recording;

            }

        }

        throw new IllegalArgumentException("No recording available with id " + id);

    }

    private Recording getRecording(long id) {

        List<Recording> recs = getRecorder().getRecordings();

        return recs.stream().filter(r -> r.getId() == id).findFirst().orElse(null);

    }

    private static <T, U> void setOption(Map<String, String> options, String name, String defaultValue, Function<String, U> converter, Consumer<U> setter) {

        if (!options.containsKey(name)) {

            return;

        }

        String v = options.get(name);

        if (v == null) {

            v = defaultValue;

        }

        try {

            setter.accept(converter.apply(v));

        } catch (IllegalArgumentException iae) {

            throw new IllegalArgumentException("Not a valid value for option '" + name + "'. " + iae.getMessage());

        }

    }

    private static <T, U> void validateOption(Map<String, String> options, String name, Function<String, U> validator) {

        try {

            String v = options.get(name);

            if (v == null) {

                return; // OK, will set default

            }

            validator.apply(v);

        } catch (IllegalArgumentException iae) {

            throw new IllegalArgumentException("Not a valid value for option '" + name + "'. " + iae.getMessage());

        }

    }

    private FlightRecorder getRecorder() throws SecurityException {

        // Synchronize on some private object that is always available

        synchronized (streamHandler) {

            if (recorder == null) {

                recorder = AccessController.doPrivileged(new PrivilegedAction<FlightRecorder>() {

                    @Override

                    public FlightRecorder run() {

                        return FlightRecorder.getFlightRecorder();

                    }

                }, null, new FlightRecorderPermission("accessFlightRecorder"));

            }

            return recorder;

        }

    }

    private static MBeanNotificationInfo[] createNotificationInfo() {

        String[] types = new String[] { AttributeChangeNotification.ATTRIBUTE_CHANGE };

        String name = AttributeChangeNotification.class.getName();

        String description = "Notifies if the RecordingState has changed for one of the recordings, for example if a recording starts or stops";

        MBeanNotificationInfo info = new MBeanNotificationInfo(types, name, description);

        return new MBeanNotificationInfo[] { info };

    }

    @Override

    public void addNotificationListener(NotificationListener listener, NotificationFilter filter, Object handback) {

        MXBeanListener mxbeanListener = new MXBeanListener(listener, filter, handback);

        listeners.add(mxbeanListener);

        AccessController.doPrivileged(new PrivilegedAction<Void>() {

            @Override

            public Void run(){

                FlightRecorder.addListener(mxbeanListener);

                return null;

            }

        }, null, new FlightRecorderPermission("accessFlightRecorder"));

        super.addNotificationListener(listener, filter, handback);

    }

    @Override

    public void removeNotificationListener(NotificationListener listener) throws ListenerNotFoundException {

        removeListeners( x -> listener == x.listener);

        super.removeNotificationListener(listener);

    }

    @Override

    public void removeNotificationListener(NotificationListener listener, NotificationFilter filter, Object handback) throws ListenerNotFoundException {

        removeListeners( x -> listener == x.listener && filter == x.filter && handback == x.handback);

        super.removeNotificationListener(listener, filter, handback);

    }

    private void removeListeners(Predicate<MXBeanListener> p) {

        List<MXBeanListener> toBeRemoved = new ArrayList<>(listeners.size());

        for (MXBeanListener l : listeners) {

            if (p.test(l)) {

                toBeRemoved.add(l);

                FlightRecorder.removeListener(l);

            }

        }

        listeners.removeAll(toBeRemoved);

    }

    private Notification createNotication(Recording recording) {

        try {

            Long id = recording.getId();

            Object oldValue = changes.get(recording.getId());

            Object newValue = getAttribute(ATTRIBUTE_RECORDINGS);

            if (recording.getState() != RecordingState.CLOSED) {

                changes.put(id, newValue);

            } else {

                changes.remove(id);

            }

            return new AttributeChangeNotification(getObjectName(), sequenceNumber.incrementAndGet(), System.currentTimeMillis(), "Recording " + recording.getName() + " is "

                    + recording.getState(), ATTRIBUTE_RECORDINGS, newValue.getClass().getName(), oldValue, newValue);

        } catch (AttributeNotFoundException | MBeanException | ReflectionException e) {

            throw new RuntimeException("Could not create notifcation for FlightRecorderMXBean. " + e.getMessage(), e);

        }

    }

}