package eu.dnetlib.data.mapreduce.util;

import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import com.google.common.collect.Maps;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.mapreduce.Mapper.Context;

import com.google.common.collect.Lists;
import com.google.protobuf.InvalidProtocolBufferException;

import eu.dnetlib.data.proto.OafProtos.Oaf;
import eu.dnetlib.data.transform.OafEntityMerger;

public class UpdateMerger {

	private static final String UPDATE_MERGER = "UPDATE_MERGE";
	private static final String N_MERGES = "N_MERGES";

	@SuppressWarnings("rawtypes")
	public static Oaf mergeBodyUpdates(final Context context, final Map<byte[], byte[]> map) throws InvalidProtocolBufferException {

		final Map<String, byte[]> stringMap = Maps.newHashMap();
		for(Entry<byte[], byte[]> e : map.entrySet()) {
			stringMap.put(Bytes.toString(e.getKey()), e.getValue());
		}

		return doMerge(context, stringMap);
	}

	public static Oaf mergeBodyUpdates(final Map<String, byte[]> map) throws InvalidProtocolBufferException {
		return doMerge(null, map);
	}

	private static Oaf doMerge(final Context context, final Map<String, byte[]> map)
			throws InvalidProtocolBufferException {

		final byte[] value = map.get(DedupUtils.BODY_S);
		if (value == null) return null;

		Oaf.Builder builder = Oaf.newBuilder(Oaf.parseFrom(value));
		final List<String> keys = Lists.newArrayList();

		// we fetch all the body updates
		for (final String o : map.keySet()) {
			if (o.startsWith("update_")) {
				keys.add(o);
			}
		}
		if (!keys.isEmpty()) {
			// we merge all the sorted updates with the body
			Collections.sort(keys);
			for (final String k : keys) {
				final Oaf update = Oaf.parseFrom(map.get(k));
				// System.out.println("\n\nBODY: \n" + body.build().toString());
				// System.out.println("UPDATE: \n" + update.toString());
				builder.mergeFrom(update);
				// System.out.println("UDPATED BODY: \n" + body.build().toString() + "\n\n");
			}

			builder = OafEntityMerger.merge(builder);

			if (context != null) {
				context.getCounter(UPDATE_MERGER, N_MERGES).increment(keys.size());
			}
		}
		return builder.build();
	}


}