package org.apache.cassandra.io.sstable;
/*
 * 
 * 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.
 * 
 */


import java.io.*;

import org.apache.cassandra.db.ColumnFamily;
import org.apache.cassandra.db.DecoratedKey;
import org.apache.cassandra.db.IColumn;
import org.apache.cassandra.db.columniterator.IColumnIterator;
import org.apache.cassandra.io.util.BufferedRandomAccessFile;

public class SSTableIdentityIterator implements Comparable<SSTableIdentityIterator>, IColumnIterator
{
    private final DecoratedKey key;
    private final long finishedAt;
    private final BufferedRandomAccessFile file;
    public final SSTableReader sstable;
    private final long dataStart;
    public final long dataSize;

    private final ColumnFamily columnFamily;
    public final int columnCount;
    private final long columnPosition;

    /**
     * Used to iterate through the columns of a row.
     * @param sstable SSTable we are reading ffrom.
     * @param file Reading using this file.
     * @param key Key of this row.
     * @param dataStart Data for this row starts at this pos.
     * @param dataSize length of row data
     * @throws IOException
     */
    public SSTableIdentityIterator(SSTableReader sstable, BufferedRandomAccessFile file, DecoratedKey key, long dataStart, long dataSize)
    throws IOException
    {
        this.sstable = sstable;
        this.file = file;
        this.key = key;
        this.dataStart = dataStart;
        this.dataSize = dataSize;
        finishedAt = dataStart + dataSize;

        try
        {
            file.seek(this.dataStart);
            IndexHelper.skipBloomFilter(file);
            IndexHelper.skipIndex(file);
            columnFamily = sstable.createColumnFamily();
            ColumnFamily.serializer().deserializeFromSSTableNoColumns(columnFamily, file);
            columnCount = file.readInt();
            columnPosition = file.getFilePointer();
        }
        catch (IOException e)
        {
            throw new IOError(e);
        }
    }

    public DecoratedKey getKey()
    {
        return key;
    }

    public ColumnFamily getColumnFamily()
    {
        return columnFamily;
    }

    public boolean hasNext()
    {
        return file.getFilePointer() < finishedAt;
    }

    public IColumn next()
    {
        try
        {
            return sstable.getColumnSerializer().deserialize(file);
        }
        catch (IOException e)
        {
            throw new IOError(e);
        }
    }

    public void remove()
    {
        throw new UnsupportedOperationException();
    }

    public void close() throws IOException
    {
        // creator is responsible for closing file when finished
    }

    public String getPath()
    {
        return file.getPath();
    }

    public void echoData(DataOutput out) throws IOException
    {
        file.seek(dataStart);
        while (file.getFilePointer() < finishedAt)
        {
            out.write(file.readByte());
        }
    }

    public ColumnFamily getColumnFamilyWithColumns() throws IOException
    {
        file.seek(columnPosition - 4); // seek to before column count int
        ColumnFamily cf = columnFamily.cloneMeShallow();
        ColumnFamily.serializer().deserializeColumns(file, cf);
        return cf;
    }

    public int compareTo(SSTableIdentityIterator o)
    {
        return key.compareTo(o.key);
    }

    public void reset()
    {
        try
        {
            file.seek(columnPosition);
        }
        catch (IOException e)
        {
            throw new IOError(e);
        }
    }
}