/*

 * Copyright (c) 2016, 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.internal.consumer;

import java.io.IOException;

import java.util.Collection;

import java.util.List;

import java.util.StringJoiner;

import jdk.jfr.EventType;

import jdk.jfr.consumer.RecordedEvent;

import jdk.jfr.consumer.RecordedObject;

import jdk.jfr.internal.LogLevel;

import jdk.jfr.internal.LogTag;

import jdk.jfr.internal.Logger;

import jdk.jfr.internal.LongMap;

import jdk.jfr.internal.MetadataDescriptor;

import jdk.jfr.internal.Type;

import jdk.jfr.internal.Utils;

/**

 * Parses a chunk.

 *

 */

public final class ChunkParser {

    static final class ParserConfiguration {

        private final boolean reuse;

        private final boolean ordered;

        private final ParserFilter eventFilter;

        long filterStart;

        long filterEnd;

        ParserConfiguration(long filterStart, long filterEnd, boolean reuse, boolean ordered, ParserFilter filter) {

            this.filterStart = filterStart;

            this.filterEnd = filterEnd;

            this.reuse = reuse;

            this.ordered = ordered;

            this.eventFilter = filter;

        }

        public ParserConfiguration() {

            this(0, Long.MAX_VALUE, false, false, ParserFilter.ACCEPT_ALL);

        }

        public boolean isOrdered() {

            return ordered;

        }

    }

    private enum CheckPointType {

        // Checkpoint that finishes a flush segment

        FLUSH(1),

        // Checkpoint contains chunk header information in the first pool

        CHUNK_HEADER(2),

        // Checkpoint contains only statics that will not change from chunk to chunk

        STATICS(4),

        // Checkpoint contains thread related information

        THREAD(8);

        private final int mask;

        private CheckPointType(int mask) {

            this.mask = mask;

        }

        private boolean is(int flags) {

            return (mask & flags) != 0;

        }

    }

    private static final long CONSTANT_POOL_TYPE_ID = 1;

    private static final String CHUNKHEADER = "jdk.types.ChunkHeader";

    private final RecordingInput input;

    private final ChunkHeader chunkHeader;

    private final MetadataDescriptor metadata;

    private final TimeConverter timeConverter;

    private final MetadataDescriptor previousMetadata;

    private final LongMap<ConstantLookup> constantLookups;

    private LongMap<Type> typeMap;

    private LongMap<Parser> parsers;

    private boolean chunkFinished;

    private Runnable flushOperation;

    private ParserConfiguration configuration;

    public ChunkParser(RecordingInput input) throws IOException {

        this(input, new ParserConfiguration());

    }

    ChunkParser(RecordingInput input, ParserConfiguration pc) throws IOException {

       this(new ChunkHeader(input), null, pc);

    }

    private ChunkParser(ChunkParser previous) throws IOException {

        this(new ChunkHeader(previous.input), previous, new ParserConfiguration());

     }

    private ChunkParser(ChunkHeader header, ChunkParser previous, ParserConfiguration pc) throws IOException {

        this.configuration = pc;

        this.input = header.getInput();

        this.chunkHeader = header;

        if (previous == null) {

            this.constantLookups = new LongMap<>();

            this.previousMetadata = null;

        } else {

            this.constantLookups = previous.constantLookups;

            this.previousMetadata = previous.metadata;

            this.configuration = previous.configuration;

        }

        this.metadata = header.readMetadata(previousMetadata);

        this.timeConverter = new TimeConverter(chunkHeader, metadata.getGMTOffset());

        if (metadata != previousMetadata) {

            ParserFactory factory = new ParserFactory(metadata, constantLookups, timeConverter);

            parsers = factory.getParsers();

            typeMap = factory.getTypeMap();

            updateConfiguration();

        } else {

            parsers = previous.parsers;

            typeMap = previous.typeMap;

        }

        constantLookups.forEach(c -> c.newPool());

        fillConstantPools(0);

        constantLookups.forEach(c -> c.getLatestPool().setResolving());

        constantLookups.forEach(c -> c.getLatestPool().resolve());

        constantLookups.forEach(c -> c.getLatestPool().setResolved());

        input.position(chunkHeader.getEventStart());

    }

    public ChunkParser nextChunkParser() throws IOException {

        return new ChunkParser(chunkHeader.nextHeader(), this, configuration);

    }

    private void updateConfiguration() {

        updateConfiguration(configuration, false);

    }

    void updateConfiguration(ParserConfiguration configuration, boolean resetEventCache) {

        this.configuration = configuration;

        parsers.forEach(p -> {

            if (p instanceof EventParser) {

                EventParser ep = (EventParser) p;

                if (resetEventCache) {

                    ep.resetCache();

                }

                String name = ep.getEventType().getName();

                ep.setOrdered(configuration.ordered);

                ep.setReuse(configuration.reuse);

                ep.setFilterStart(configuration.filterStart);

                ep.setFilterEnd(configuration.filterEnd);

                long threshold = configuration.eventFilter.getThreshold(name);

                if (threshold >= 0) {

                    ep.setEnabled(true);

                    ep.setThresholdNanos(threshold);

                } else {

                    ep.setEnabled(false);

                    ep.setThresholdNanos(Long.MAX_VALUE);

                }

            }

        });

    }

    /**

     * Reads an event and returns null when segment or chunk ends.

     *

     * @param awaitNewEvents wait for new data.

     */

    RecordedEvent readStreamingEvent(boolean awaitNewEvents) throws IOException {

        long absoluteChunkEnd = chunkHeader.getEnd();

        while (true) {

            RecordedEvent event = readEvent();

            if (event != null) {

                return event;

            }

            if (!awaitNewEvents) {

                return null;

            }

            long lastValid = absoluteChunkEnd;

            long metadataPoistion = chunkHeader.getMetataPosition();

            long contantPosition = chunkHeader.getConstantPoolPosition();

            chunkFinished = awaitUpdatedHeader(absoluteChunkEnd);

            if (chunkFinished) {

                Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "At chunk end");

                return null;

            }

            absoluteChunkEnd = chunkHeader.getEnd();

            // Read metadata and constant pools for the next segment

            if (chunkHeader.getMetataPosition() != metadataPoistion) {

                Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Found new metadata in chunk. Rebuilding types and parsers");

                MetadataDescriptor metadata = chunkHeader.readMetadata(previousMetadata);

                ParserFactory factory = new ParserFactory(metadata, constantLookups, timeConverter);

                parsers = factory.getParsers();

                typeMap = factory.getTypeMap();

                updateConfiguration();;

            }

            if (contantPosition != chunkHeader.getConstantPoolPosition()) {

                Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Found new constant pool data. Filling up pools with new values");

                constantLookups.forEach(c -> c.getLatestPool().setAllResolved(false));

                fillConstantPools(contantPosition + chunkHeader.getAbsoluteChunkStart());

                constantLookups.forEach(c -> c.getLatestPool().setResolving());

                constantLookups.forEach(c -> c.getLatestPool().resolve());

                constantLookups.forEach(c -> c.getLatestPool().setResolved());

            }

            input.position(lastValid);

        }

    }

    /**

     * Reads an event and returns null when the chunk ends

     */

    public RecordedEvent readEvent() throws IOException {

        long absoluteChunkEnd = chunkHeader.getEnd();

        while (input.position() < absoluteChunkEnd) {

            long pos = input.position();

            int size = input.readInt();

            if (size == 0) {

                throw new IOException("Event can't have zero size");

            }

            long typeId = input.readLong();

            if (typeId != 0) { // Not metadata event

                Parser p = parsers.get(typeId);

                if (p instanceof EventParser) {

                    EventParser ep = (EventParser) p;

                    RecordedEvent event = ep.parse(input);

                    if (event != null) {

                        input.position(pos + size);

                        return event;

                    }

                }

                if (typeId == 1 && flushOperation != null) { // checkpoint event

                    parseCheckpoint();

                }

            }

            input.position(pos + size);

        }

        return null;

    }

    private void parseCheckpoint() throws IOException {

        // Content has been parsed previously. This

        // is to trigger flush

        input.readLong(); // timestamp

        input.readLong(); // duration

        input.readLong(); // delta

        byte typeFlags = input.readByte();

        if (CheckPointType.FLUSH.is(typeFlags)) {

            flushOperation.run();

        }

    }

    private boolean awaitUpdatedHeader(long absoluteChunkEnd) throws IOException {

        if (Logger.shouldLog(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO)) {

            Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Waiting for more data (streaming). Read so far: " + chunkHeader.getChunkSize() + " bytes");

        }

        while (true) {

            chunkHeader.refresh();

            if (absoluteChunkEnd != chunkHeader.getEnd()) {

                return false;

            }

            if (chunkHeader.isFinished()) {

                return true;

            }

        }

    }

    private void fillConstantPools(long abortCP) throws IOException {

        long thisCP = chunkHeader.getConstantPoolPosition() + chunkHeader.getAbsoluteChunkStart();

        long lastCP = -1;

        long delta = -1;

        boolean logTrace = Logger.shouldLog(LogTag.JFR_SYSTEM_PARSER, LogLevel.TRACE);

        while (thisCP != abortCP && delta != 0) {

            input.position(thisCP);

            lastCP = thisCP;

            int size = input.readInt(); // size

            long typeId = input.readLong();

            if (typeId != CONSTANT_POOL_TYPE_ID) {

                throw new IOException("Expected check point event (id = 1) at position " + lastCP + ", but found type id = " + typeId);

            }

            input.readLong(); // timestamp

            input.readLong(); // duration

            delta = input.readLong();

            thisCP += delta;

            boolean flush = input.readBoolean();

            int poolCount = input.readInt();

            final long logLastCP = lastCP;

            final long logDelta = delta;

            if (logTrace) {

                Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.TRACE, () -> {

                    return "New constant pool: startPosition=" + logLastCP + ", size=" + size + ", deltaToNext=" + logDelta + ", flush=" + flush + ", poolCount=" + poolCount;

                });

            }

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

                long id = input.readLong(); // type id

                ConstantLookup lookup = constantLookups.get(id);

                Type type = typeMap.get(id);

                if (lookup == null) {

                    if (type == null) {

                        throw new IOException(

                                "Error parsing constant pool type " + getName(id) + " at position " + input.position() + " at check point between [" + lastCP + ", " + lastCP + size + "]");

                    }

                    if (type.getName() != CHUNKHEADER) {

                        Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Found constant pool(" + id + ") that is never used");

                    }

                    ConstantMap pool = new ConstantMap(ObjectFactory.create(type, timeConverter), type.getName());

                    lookup = new ConstantLookup(pool, type);

                    constantLookups.put(type.getId(), lookup);

                }

                Parser parser = parsers.get(id);

                if (parser == null) {

                    throw new IOException("Could not find constant pool type with id = " + id);

                }

                try {

                    int count = input.readInt();

                    if (count == 0) {

                        throw new InternalError("Pool " + type.getName() + " must contain at least one element ");

                    }

                    if (logTrace) {

                        Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.TRACE, "Constant Pool " + i + ": " + type.getName());

                    }

                    for (int j = 0; j < count; j++) {

                        long key = input.readLong();

                        Object resolved = lookup.getPreviousResolved(key);

                        if (resolved == null) {

                            Object v = parser.parse(input);

                            logConstant(key, v, false);

                            lookup.getLatestPool().put(key, v);

                        } else {

                            parser.skip(input);

                            logConstant(key, resolved, true);

                            lookup.getLatestPool().putResolved(key, resolved);

                        }

                    }

                } catch (Exception e) {

                    throw new IOException("Error parsing constant pool type " + getName(id) + " at position " + input.position() + " at check point between [" + lastCP + ", " + lastCP + size + "]",

                            e);

                }

            }

            if (input.position() != lastCP + size) {

                throw new IOException("Size of check point event doesn't match content");

            }

        }

    }

    private void logConstant(long key, Object v, boolean preresolved) {

        if (!Logger.shouldLog(LogTag.JFR_SYSTEM_PARSER, LogLevel.TRACE)) {

            return;

        }

        String valueText;

        if (v.getClass().isArray()) {

            Object[] array = (Object[]) v;

            StringJoiner sj = new StringJoiner(", ", "{", "}");

            for (int i = 0; i < array.length; i++) {

                sj.add(textify(array[i]));

            }

            valueText = sj.toString();

        } else {

            valueText = textify(v);

        }

        String suffix  = preresolved ? " (presolved)" :"";

        Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.TRACE, "Constant: " + key + " = " + valueText + suffix);

    }

    private String textify(Object o) {

        if (o == null) { // should not happen

            return "null";

        }

        if (o instanceof String) {

            return "\"" + String.valueOf(o) + "\"";

        }

        if (o instanceof RecordedObject) {

            return o.getClass().getName();

        }

        if (o.getClass().isArray()) {

            Object[] array = (Object[]) o;

            if (array.length > 0) {

                return textify(array[0]) + "[]"; // can it be recursive?

            }

        }

        return String.valueOf(o);

    }

    private String getName(long id) {

        Type type = typeMap.get(id);

        return type == null ? ("unknown(" + id + ")") : type.getName();

    }

    public Collection<Type> getTypes() {

        return metadata.getTypes();

    }

    public List<EventType> getEventTypes() {

        return metadata.getEventTypes();

    }

    public boolean isLastChunk() throws IOException {

        return chunkHeader.isLastChunk();

    }

    ChunkParser newChunkParser() throws IOException {

        return new ChunkParser(this);

    }

    public boolean isChunkFinished() {

        return chunkFinished;

    }

    public void setFlushOperation(Runnable flushOperation) {

        this.flushOperation = flushOperation;

    }

    public long getChunkDuration() {

        return chunkHeader.getDurationNanos();

    }

    public long getStartNanos() {

        return chunkHeader.getStartNanos();

    }

}