/**
 * 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.crunch.types.avro;

import java.io.IOException;

import org.apache.avro.mapred.AvroWrapper;
import org.apache.avro.util.Utf8;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.compress.CompressionCodecFactory;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.RecordReader;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.LineRecordReader;

/**
 * An {@link org.apache.hadoop.mapred.InputFormat} for text files. Each line is
 * a {@link Utf8} key; values are null.
 */
public class AvroUtf8InputFormat extends FileInputFormat<AvroWrapper<Utf8>, NullWritable> {

  static class Utf8LineRecordReader extends RecordReader<AvroWrapper<Utf8>, NullWritable> {

    private LineRecordReader lineRecordReader;

    private AvroWrapper<Utf8> currentKey = new AvroWrapper<Utf8>();

    public Utf8LineRecordReader() throws IOException {
      this.lineRecordReader = new LineRecordReader();
    }

    public void close() throws IOException {
      lineRecordReader.close();
    }

    public float getProgress() throws IOException {
      return lineRecordReader.getProgress();
    }

    @Override
    public AvroWrapper<Utf8> getCurrentKey() throws IOException, InterruptedException {
      Text txt = lineRecordReader.getCurrentValue();
      currentKey.datum(new Utf8(txt.toString()));
      return currentKey;
    }

    @Override
    public NullWritable getCurrentValue() throws IOException, InterruptedException {
      return NullWritable.get();
    }

    @Override
    public void initialize(InputSplit split, TaskAttemptContext context) throws IOException, InterruptedException {
      lineRecordReader.initialize(split, context);
    }

    @Override
    public boolean nextKeyValue() throws IOException, InterruptedException {
      return lineRecordReader.nextKeyValue();
    }
  }

  private CompressionCodecFactory compressionCodecs = null;

  public void configure(Configuration conf) {
    compressionCodecs = new CompressionCodecFactory(conf);
  }

  protected boolean isSplitable(FileSystem fs, Path file) {
    return compressionCodecs.getCodec(file) == null;
  }

  @Override
  public RecordReader<AvroWrapper<Utf8>, NullWritable> createRecordReader(InputSplit split, TaskAttemptContext context)
      throws IOException, InterruptedException {
    return new Utf8LineRecordReader();
  }
}
