/*
 * 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.kafka.streams.state.internals;

import org.apache.kafka.common.serialization.Serde;
import org.apache.kafka.common.serialization.Serdes;
import org.apache.kafka.common.utils.Bytes;
import org.apache.kafka.streams.state.StateSerdes;

import java.nio.ByteBuffer;

public class WindowStoreUtils {

    private static final int SEQNUM_SIZE = 4;
    private static final int TIMESTAMP_SIZE = 8;

    /** Inner byte array serde used for segments */
    static final Serde<Bytes> INNER_KEY_SERDE = Serdes.Bytes();
    static final Serde<byte[]> INNER_VALUE_SERDE = Serdes.ByteArray();

    static StateSerdes<Bytes, byte[]> getInnerStateSerde(final String topic) {
        return new StateSerdes<>(topic, INNER_KEY_SERDE, INNER_VALUE_SERDE);
    }

    static <K> Bytes toBinaryKey(K key, final long timestamp, final int seqnum, StateSerdes<K, ?> serdes) {
        byte[] serializedKey = serdes.rawKey(key);
        return toBinaryKey(serializedKey, timestamp, seqnum);
    }

    static Bytes toBinaryKey(byte[] serializedKey, final long timestamp, final int seqnum) {
        ByteBuffer buf = ByteBuffer.allocate(serializedKey.length + TIMESTAMP_SIZE + SEQNUM_SIZE);
        buf.put(serializedKey);
        buf.putLong(timestamp);
        buf.putInt(seqnum);

        return Bytes.wrap(buf.array());
    }

    static <K> K keyFromBinaryKey(byte[] binaryKey, StateSerdes<K, ?> serdes) {
        byte[] bytes = new byte[binaryKey.length - TIMESTAMP_SIZE - SEQNUM_SIZE];

        System.arraycopy(binaryKey, 0, bytes, 0, bytes.length);

        return serdes.keyFrom(bytes);
    }

    static Bytes bytesKeyFromBinaryKey(byte[] binaryKey) {
        byte[] bytes = new byte[binaryKey.length - TIMESTAMP_SIZE - SEQNUM_SIZE];

        System.arraycopy(binaryKey, 0, bytes, 0, bytes.length);

        return Bytes.wrap(bytes);
    }

    static long timestampFromBinaryKey(byte[] binaryKey) {
        return ByteBuffer.wrap(binaryKey).getLong(binaryKey.length - TIMESTAMP_SIZE - SEQNUM_SIZE);
    }

    static int sequenceNumberFromBinaryKey(byte[] binaryKey) {
        return ByteBuffer.wrap(binaryKey).getInt(binaryKey.length - SEQNUM_SIZE);
    }
}