// MongoImportFormat.java
/*
 * Copyright 2010 10gen Inc.
 * 
 * Licensed 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 com.mongodb.hadoop.mapred;

import java.util.*;

import com.mongodb.hadoop.input.*;
import com.mongodb.hadoop.mapred.input.MongoInputSplit;
import com.mongodb.hadoop.mapred.input.MongoRecordReader;
import com.mongodb.hadoop.util.*;
import org.apache.commons.logging.*;
import org.apache.hadoop.conf.*;
import org.apache.hadoop.mapred.*;
import org.apache.hadoop.io.*;
import org.apache.hadoop.mapred.InputFormat;
import org.apache.hadoop.mapred.InputSplit;
import org.apache.hadoop.mapred.RecordReader;
import org.apache.hadoop.mapreduce.*;
import org.bson.*;

import com.mongodb.hadoop.MongoConfig;
import com.mongodb.hadoop.mapred.input.*;
import com.mongodb.hadoop.io.*;

@SuppressWarnings("deprecation")
public class MongoInputFormat implements InputFormat<BSONWritable, BSONWritable> {

    public RecordReader<BSONWritable, BSONWritable> getRecordReader(InputSplit split,
                                                                    JobConf job,
                                                                    Reporter reporter) {
        if (!(split instanceof MongoInputSplit))
            throw new IllegalStateException("Creation of a new RecordReader requires a MongoInputSplit instance.");

        final MongoInputSplit mis = (MongoInputSplit) split;

        return new MongoRecordReader(mis);
    }

    public InputSplit[] getSplits(JobConf job, int numSplits) {
        final MongoConfig conf = new MongoConfig(job);
        // TODO - Support allowing specification of numSplits to affect our ops?
        final List<org.apache.hadoop.mapreduce.InputSplit> splits = MongoSplitter.calculateSplits( conf );
        // TODO - Make me less egregiously inefficient.
        InputSplit[] classicSplits = new InputSplit[splits.size()];
        for ( int i = 0; i < splits.size(); i++ ) {
            classicSplits[i] = new MongoInputSplit( (com.mongodb.hadoop.input.MongoInputSplit) splits.get( i ) );
        }
        return classicSplits;
    }

    public boolean verifyConfiguration(Configuration conf) {
        return true;
    }

    private static final Log log = LogFactory.getLog(MongoInputFormat.class);

}