/*
 * 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.cassandra.db.marshal;

import java.nio.ByteBuffer;
import java.util.Date;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.cassandra.cql3.CQL3Type;
import org.apache.cassandra.serializers.TypeSerializer;
import org.apache.cassandra.serializers.MarshalException;
import org.apache.cassandra.serializers.TimestampSerializer;
import org.apache.cassandra.utils.ByteBufferUtil;

/**
 * Type for date-time values.
 *
 * This is meant as a replacement for DateType, as DateType wrongly compare
 * pre-unix-epoch dates, sorting them *after* post-unix-epoch ones (due to it's
 * use of unsigned bytes comparison).
 */
public class TimestampType extends AbstractType<Date>
{
    private static final Logger logger = LoggerFactory.getLogger(TimestampType.class);

    public static final TimestampType instance = new TimestampType();

    private TimestampType() {} // singleton

    public int compare(ByteBuffer o1, ByteBuffer o2)
    {
        return LongType.compareLongs(o1, o2);
    }

    public ByteBuffer fromString(String source) throws MarshalException
    {
      // Return an empty ByteBuffer for an empty string.
      if (source.isEmpty())
          return ByteBufferUtil.EMPTY_BYTE_BUFFER;

      return ByteBufferUtil.bytes(TimestampSerializer.dateStringToTimestamp(source));
    }

    @Override
    public boolean isCompatibleWith(AbstractType<?> previous)
    {
        if (super.isCompatibleWith(previous))
            return true;

        if (previous instanceof DateType)
        {
            logger.warn("Changing from DateType to TimestampType is allowed, but be wary that they sort differently for pre-unix-epoch timestamps "
                      + "(negative timestamp values) and thus this change will corrupt your data if you have such negative timestamp. So unless you "
                      + "know that you don't have *any* pre-unix-epoch timestamp you should change back to DateType");
            return true;
        }

        return false;
    }

    @Override
    public boolean isValueCompatibleWithInternal(AbstractType<?> otherType)
    {
        return this == otherType || otherType == DateType.instance || otherType == LongType.instance;
    }

    public CQL3Type asCQL3Type()
    {
        return CQL3Type.Native.TIMESTAMP;
    }

    public TypeSerializer<Date> getSerializer()
    {
        return TimestampSerializer.instance;
    }
}