/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.jackrabbit.oak.segment.standby;

import static org.mockito.Mockito.mock;

import java.nio.charset.StandardCharsets;
import java.util.UUID;

import org.apache.jackrabbit.guava.common.hash.Hashing;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;

import org.apache.jackrabbit.oak.commons.Buffer;
import org.apache.jackrabbit.oak.segment.RecordId;
import org.apache.jackrabbit.oak.segment.Segment;
import org.apache.jackrabbit.oak.segment.SegmentId;
import org.apache.jackrabbit.oak.segment.SegmentIdProvider;
import org.apache.jackrabbit.oak.segment.SegmentReader;
import org.apache.jackrabbit.oak.segment.SegmentStore;

public class StandbyTestUtils {

    private StandbyTestUtils() {
        // Prevent instantiation.
    }

    public static RecordId mockRecordId(long msb, long lsb, int offset) {
        return new RecordId(new SegmentId(mock(SegmentStore.class), msb, lsb), offset);
    }

    public static Segment mockSegment(UUID uuid, byte[] buffer) {
        SegmentStore store = mock(SegmentStore.class);
        SegmentIdProvider idProvider = mock(SegmentIdProvider.class);
        long msb = uuid.getMostSignificantBits();
        long lsb = uuid.getLeastSignificantBits();
        SegmentId id = new SegmentId(store, msb, lsb);
        Buffer data = Buffer.wrap(buffer);
        return new Segment(idProvider, id, data);
    }

    public static long hash(byte[] data) {
        return Hashing.murmur3_32().newHasher().putBytes(data).hash().padToLong();
    }
    
    public static long hash(byte mask, long blobLength, byte[] data) {
        return Hashing.murmur3_32().newHasher().putByte(mask).putLong(blobLength).putBytes(data).hash().padToLong();
    }
    
    public static byte createMask(int currentChunk, int totalChunks) {
        byte mask = 0;
        if (currentChunk == 1) {
            mask = (byte) (mask | (1 << 0));
        }

        if (currentChunk == totalChunks) {
            mask = (byte) (mask | (1 << 1));
        }

        return mask;
    }
    
    public static ByteBuf createBlobChunkBuffer(byte header, long blobLength, String blobId, byte[] data, byte mask) {
        byte[] blobIdBytes = blobId.getBytes(StandardCharsets.UTF_8);
        
        ByteBuf buf = Unpooled.buffer();
        buf.writeInt(1 + 1 + 8 + 4 + blobIdBytes.length + 8 + data.length);
        buf.writeByte(header);
        buf.writeByte(mask);
        buf.writeLong(blobLength);
        buf.writeInt(blobIdBytes.length);
        buf.writeBytes(blobIdBytes);
        buf.writeLong(hash(mask, blobLength, data));
        buf.writeBytes(data);
        
        return buf;
    }

}
