/*
 * 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.UUID;
import java.util.regex.Pattern;

import org.apache.cassandra.cql.jdbc.JdbcTimeUUID;
import org.apache.cassandra.cql3.CQL3Type;
import org.apache.cassandra.utils.ByteBufferUtil;
import org.apache.cassandra.utils.UUIDGen;

public class TimeUUIDType extends AbstractType<UUID>
{
    public static final TimeUUIDType instance = new TimeUUIDType();

    static final Pattern regexPattern = Pattern.compile("[A-Fa-f0-9]{8}\\-[A-Fa-f0-9]{4}\\-[A-Fa-f0-9]{4}\\-[A-Fa-f0-9]{4}\\-[A-Fa-f0-9]{12}");

    TimeUUIDType() {} // singleton

    public UUID compose(ByteBuffer bytes)
    {
        return JdbcTimeUUID.instance.compose(bytes);
    }

    public ByteBuffer decompose(UUID value)
    {
        return JdbcTimeUUID.instance.decompose(value);
    }

    public int compare(ByteBuffer o1, ByteBuffer o2)
    {
        if (o1.remaining() == 0)
        {
            return o2.remaining() == 0 ? 0 : -1;
        }
        if (o2.remaining() == 0)
        {
            return 1;
        }
        int res = compareTimestampBytes(o1, o2);
        if (res != 0)
            return res;
        return o1.compareTo(o2);
    }

    private static int compareTimestampBytes(ByteBuffer o1, ByteBuffer o2)
    {
        int o1Pos = o1.position();
        int o2Pos = o2.position();

        int d = (o1.get(o1Pos+6) & 0xF) - (o2.get(o2Pos+6) & 0xF);
        if (d != 0) return d;

        d = (o1.get(o1Pos+7) & 0xFF) - (o2.get(o2Pos+7) & 0xFF);
        if (d != 0) return d;

        d = (o1.get(o1Pos+4) & 0xFF) - (o2.get(o2Pos+4) & 0xFF);
        if (d != 0) return d;

        d = (o1.get(o1Pos+5) & 0xFF) - (o2.get(o2Pos+5) & 0xFF);
        if (d != 0) return d;

        d = (o1.get(o1Pos) & 0xFF) - (o2.get(o2Pos) & 0xFF);
        if (d != 0) return d;

        d = (o1.get(o1Pos+1) & 0xFF) - (o2.get(o2Pos+1) & 0xFF);
        if (d != 0) return d;

        d = (o1.get(o1Pos+2) & 0xFF) - (o2.get(o2Pos+2) & 0xFF);
        if (d != 0) return d;

        return (o1.get(o1Pos+3) & 0xFF) - (o2.get(o2Pos+3) & 0xFF);
    }

    public String getString(ByteBuffer bytes)
    {
        try
        {
            return JdbcTimeUUID.instance.getString(bytes);
        }
        catch (org.apache.cassandra.cql.jdbc.MarshalException e)
        {
            throw new MarshalException(e.getMessage());
        }
    }

    // This accepts dates are valid TimeUUID represensation, which is bogus
    // (see #4936) but kept for CQL2 for compatibility sake.
    @Override
    public ByteBuffer fromStringCQL2(String source) throws MarshalException
    {
        // Return an empty ByteBuffer for an empty string.
        if (source.isEmpty())
            return ByteBufferUtil.EMPTY_BYTE_BUFFER;

        ByteBuffer idBytes = null;

        // ffffffff-ffff-ffff-ffff-ffffffffff
        if (regexPattern.matcher(source).matches())
        {
            UUID uuid = null;
            try
            {
                uuid = UUID.fromString(source);
                idBytes = decompose(uuid);
            }
            catch (IllegalArgumentException e)
            {
                throw new MarshalException(String.format("unable to make UUID from '%s'", source), e);
            }

            if (uuid.version() != 1)
                throw new MarshalException("TimeUUID supports only version 1 UUIDs");
        }
        else
        {
            idBytes = ByteBuffer.wrap(UUIDGen.getTimeUUIDBytes(DateType.dateStringToTimestamp(source)));
        }

        return idBytes;
    }

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

        ByteBuffer idBytes = null;

        // ffffffff-ffff-ffff-ffff-ffffffffff
        if (regexPattern.matcher(source).matches())
        {
            UUID uuid = null;
            try
            {
                uuid = UUID.fromString(source);
                idBytes = decompose(uuid);
            }
            catch (IllegalArgumentException e)
            {
                throw new MarshalException(String.format("Unable to make UUID from '%s'", source), e);
            }

            if (uuid.version() != 1)
                throw new MarshalException("TimeUUID supports only version 1 UUIDs");
        }
        else
        {
            throw new MarshalException(String.format("Unknown timeuuid representation: %s", source));
        }
        return idBytes;
    }

    public void validate(ByteBuffer bytes) throws MarshalException
    {
        if (bytes.remaining() != 16 && bytes.remaining() != 0)
            throw new MarshalException(String.format("TimeUUID should be 16 or 0 bytes (%d)", bytes.remaining()));
        ByteBuffer slice = bytes.slice();
        // version is bits 4-7 of byte 6.
        if (bytes.remaining() > 0)
        {
            slice.position(6);
            if ((slice.get() & 0xf0) != 0x10)
                throw new MarshalException("Invalid version for TimeUUID type.");
        }
    }

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