/*

 * 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.jfr.internal.consumer;

import java.io.DataInput;

import java.io.IOException;

import jdk.jfr.internal.LogLevel;

import jdk.jfr.internal.LogTag;

import jdk.jfr.internal.Logger;

import jdk.jfr.internal.MetadataDescriptor;

public final class ChunkHeader {

    private static final long METADATA_TYPE_ID = 0;

    private static final byte[] FILE_MAGIC = { 'F', 'L', 'R', '\0' };

    private final short major;

    private final short minor;

    private final long chunkSize;

    private final long chunkStartTicks;

    private final long ticksPerSecond;

    private final long chunkStartNanos;

    private final long metadataPosition;

 //   private final long absoluteInitialConstantPoolPosition;

    private final long absoluteChunkEnd;

    private final long absoluteEventStart;

    private final long absoluteChunkStart;

    private final boolean lastChunk;

    private final RecordingInput input;

    private final long durationNanos;

    private final long id;

    private long constantPoolPosition;

    public ChunkHeader(RecordingInput input) throws IOException {

        this(input, 0, 0);

    }

    private ChunkHeader(RecordingInput input, long absoluteChunkStart, long id) throws IOException {

        input.position(absoluteChunkStart);

        if (input.position() >= input.size()) {

            throw new IOException("Chunk contains no data");

        }

        verifyMagic(input);

        this.input = input;

        this.id = id;

        Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Chunk " + id);

        Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Chunk: startPosition=" + absoluteChunkStart);

        major = input.readRawShort();

        Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Chunk: major=" + major);

        minor = input.readRawShort();

        Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Chunk: minor=" + minor);

        if (major != 1 && major != 2) {

            throw new IOException("File version " + major + "." + minor + ". Only Flight Recorder files of version 1.x and 2.x can be read by this JDK.");

        }

        chunkSize = input.readRawLong();

        Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Chunk: chunkSize=" + chunkSize);

        this.constantPoolPosition = input.readRawLong();

        Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Chunk: constantPoolPosition=" + constantPoolPosition);

        metadataPosition = input.readRawLong();

        Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Chunk: metadataPosition=" + metadataPosition);

        chunkStartNanos = input.readRawLong(); // nanos since epoch

        Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Chunk: startNanos=" + chunkStartNanos);

        durationNanos = input.readRawLong(); // duration nanos, not used

        Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Chunk: durationNanos=" + durationNanos);

        chunkStartTicks = input.readRawLong();

        Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Chunk: startTicks=" + chunkStartTicks);

        ticksPerSecond = input.readRawLong();

        Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Chunk: ticksPerSecond=" + ticksPerSecond);

        input.readRawInt(); // features, not used

        // set up boundaries

        this.absoluteChunkStart = absoluteChunkStart;

        absoluteChunkEnd = absoluteChunkStart + chunkSize;

        lastChunk = input.size() == absoluteChunkEnd;

        absoluteEventStart = input.position();

        // read metadata

        input.position(absoluteEventStart);

    }

    public ChunkHeader nextHeader() throws IOException {

        return new ChunkHeader(input, absoluteChunkEnd, id + 1);

    }

    public MetadataDescriptor readMetadata() throws IOException {

        input.position(absoluteChunkStart + metadataPosition);

        input.readInt(); // size

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

        if (id != METADATA_TYPE_ID) {

            throw new IOException("Expected metadata event. Type id=" + id + ", should have been " + METADATA_TYPE_ID);

        }

        input.readLong(); // start time

        input.readLong(); // duration

        long metadataId = input.readLong();

        Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.TRACE, "Metadata id=" + metadataId);

        // No need to read if metadataId == lastMetadataId, but we

        // do it for verification purposes.

        return MetadataDescriptor.read(input);

    }

    public boolean isLastChunk() {

        return lastChunk;

    }

    public short getMajor() {

        return major;

    }

    public short getMinor() {

        return minor;

    }

    public long getAbsoluteChunkStart() {

        return absoluteChunkStart;

    }

    public long getConstantPoolPosition() {

        return constantPoolPosition;

    }

    public long getStartTicks() {

        return chunkStartTicks;

    }

    public double getTicksPerSecond() {

        return ticksPerSecond;

    }

    public long getStartNanos() {

        return chunkStartNanos;

    }

    public long getEnd() {

        return absoluteChunkEnd;

    }

    public long getSize() {

        return chunkSize;

    }

    public long getDuration() {

        return durationNanos;

    }

    public RecordingInput getInput() {

        return input;

    }

    private static void verifyMagic(DataInput input) throws IOException {

        for (byte c : FILE_MAGIC) {

            if (input.readByte() != c) {

                throw new IOException("Not a Flight Recorder file");

            }

        }

    }

    public long getEventStart() {

        return absoluteEventStart;

    }

}