/*

 * 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.jfr.consumer;

import java.io.IOException;

import java.util.Collection;

import java.util.List;

import jdk.jfr.EventType;

import jdk.jfr.internal.LogLevel;

import jdk.jfr.internal.LogTag;

import jdk.jfr.internal.Logger;

import jdk.jfr.internal.MetadataDescriptor;

import jdk.jfr.internal.Type;

import jdk.jfr.internal.consumer.ChunkHeader;

import jdk.jfr.internal.consumer.RecordingInput;

/**

 * Parses a chunk.

 *

 */

final class ChunkParser {

    private static final long CONSTANT_POOL_TYPE_ID = 1;

    private final RecordingInput input;

    private final LongMap<Parser> parsers;

    private final ChunkHeader chunkHeader;

    private final long absoluteChunkEnd;

    private final MetadataDescriptor metadata;

    private final LongMap<Type> typeMap;

    private final TimeConverter timeConverter;

    public ChunkParser(RecordingInput input) throws IOException {

      this(new ChunkHeader(input));

    }

    private ChunkParser(ChunkHeader header) throws IOException {

        this.input = header.getInput();

        this.chunkHeader = header;

        this.metadata = header.readMetadata();

        this.absoluteChunkEnd = header.getEnd();

        this.timeConverter =  new TimeConverter(chunkHeader);

        ParserFactory factory = new ParserFactory(metadata, timeConverter);

        LongMap<ConstantMap> constantPools = factory.getConstantPools();

        parsers = factory.getParsers();

        typeMap = factory.getTypeMap();

        fillConstantPools(parsers, constantPools);

        constantPools.forEach(ConstantMap::setIsResolving);

        constantPools.forEach(ConstantMap::resolve);

        constantPools.forEach(ConstantMap::setResolved);

        input.position(chunkHeader.getEventStart());

    }

    public RecordedEvent readEvent() throws IOException {

        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 > CONSTANT_POOL_TYPE_ID) { // also skips metadata (id=0)

                Parser ep = parsers.get(typeId);

                if (ep instanceof EventParser) {

                    return (RecordedEvent) ep.parse(input);

                }

            }

            input.position(pos + size);

        }

        return null;

    }

    private void fillConstantPools(LongMap<Parser> typeParser, LongMap<ConstantMap> constantPools) throws IOException {

        long nextCP = chunkHeader.getAbsoluteChunkStart();

        long deltaToNext = chunkHeader.getConstantPoolPosition();

        while (deltaToNext != 0) {

            nextCP += deltaToNext;

            input.position(nextCP);

            final long position = nextCP;

            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 " + nextCP + ", but found type id = " + typeId);

            }

            input.readLong(); // timestamp

            input.readLong(); // duration

            deltaToNext = input.readLong();

            final long delta = deltaToNext;

            boolean flush = input.readBoolean();

            int poolCount = input.readInt();

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

                return "New constant pool: startPosition=" + position +

                        ", size=" + size + ", deltaToNext=" + delta +

                        ", flush=" + flush + ", poolCount=" + poolCount;

            });

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

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

                ConstantMap pool = constantPools.get(id);

                Type type = typeMap.get(id);

                if (pool == null) {

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

                    if (type == null) {

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

                    }

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

                    constantPools.put(type.getId(), pool);

                }

                Parser parser = typeParser.get(id);

                if (parser == null) {

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

                }

                try {

                    int count = input.readInt();

                    Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.TRACE, () -> "Constant: " + getName(id) + "[" + count + "]");

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

                        long key = input.readLong();

                        Object value = parser.parse(input);

                        pool.put(key, value);

                    }

                } catch (Exception e) {

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

                }

            }

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

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

            }

        }

    }

    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() {

        return chunkHeader.isLastChunk();

    }

    public ChunkParser nextChunkParser() throws IOException {

        return new ChunkParser(chunkHeader.nextHeader());

    }

}