package eu.dnetlib.pace.util;

import java.util.ArrayList;
import java.util.List;

import org.apache.commons.lang3.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.spark.sql.Row;
import org.apache.spark.sql.types.ArrayType;
import org.apache.spark.sql.types.DataType;
import org.apache.spark.sql.types.StringType;

import eu.dnetlib.pace.config.DedupConfig;
import eu.dnetlib.pace.config.WfConfig;
import eu.dnetlib.pace.tree.support.TreeProcessor;

public class BlockProcessor {

	public static final List<String> accumulators = new ArrayList<>();

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

	private DedupConfig dedupConf;

	private final int identifierFieldPos;
	private final int orderFieldPos;

	public static void constructAccumulator(final DedupConfig dedupConf) {
		accumulators.add(String.format("%s::%s", dedupConf.getWf().getEntityType(), "records per hash key = 1"));
		accumulators
			.add(
				String
					.format(
						"%s::%s", dedupConf.getWf().getEntityType(), "missing " + dedupConf.getWf().getOrderField()));
		accumulators
			.add(
				String
					.format(
						"%s::%s", dedupConf.getWf().getEntityType(),
						String
							.format(
								"Skipped records for count(%s) >= %s", dedupConf.getWf().getOrderField(),
								dedupConf.getWf().getGroupMaxSize())));
		accumulators.add(String.format("%s::%s", dedupConf.getWf().getEntityType(), "skip list"));
		accumulators.add(String.format("%s::%s", dedupConf.getWf().getEntityType(), "dedupSimilarity (x2)"));
		accumulators
			.add(String.format("%s::%s", dedupConf.getWf().getEntityType(), "d < " + dedupConf.getWf().getThreshold()));
	}

	public BlockProcessor(DedupConfig dedupConf, int identifierFieldPos, int orderFieldPos) {
		this.dedupConf = dedupConf;
		this.identifierFieldPos = identifierFieldPos;
		this.orderFieldPos = orderFieldPos;
	}

	public void processSortedRows(final List<Row> documents, final Reporter context) {
		if (documents.size() > 1) {
//            log.info("reducing key: '" + key + "' records: " + q.size());
			processRows(documents, context);

		} else {
			context.incrementCounter(dedupConf.getWf().getEntityType(), "records per hash key = 1", 1);
		}
	}

	private void processRows(final List<Row> queue, final Reporter context) {

		IncrementalConnectedComponents icc = new IncrementalConnectedComponents(queue.size());

		for (int i = 0; i < queue.size(); i++) {
			final Row pivot = queue.get(i);

			final String idPivot = pivot.getString(identifierFieldPos); // identifier
			final Object fieldsPivot = getJavaValue(pivot, orderFieldPos);
			final String fieldPivot = (fieldsPivot == null) ? "" : fieldsPivot.toString();
			final WfConfig wf = dedupConf.getWf();

			if (fieldPivot != null) {
				for (int j = icc.nextUnconnected(i, i + 1); j >= 0
					&& j < queue.size(); j = icc.nextUnconnected(i, j + 1)) {
					final Row curr = queue.get(j);
					final String idCurr = curr.getString(identifierFieldPos); // identifier

					if (mustSkip(idCurr)) {
						context.incrementCounter(wf.getEntityType(), "skip list", 1);
						break;
					}

					if (wf.getSlidingWindowSize() > 0 && (j - i) > wf.getSlidingWindowSize()) {
						break;
					}

					final Object fieldsCurr = getJavaValue(curr, orderFieldPos);
					final String fieldCurr = (fieldsCurr == null) ? null : fieldsCurr.toString();

					if (!idCurr.equals(idPivot) && (fieldCurr != null)) {

						final TreeProcessor treeProcessor = new TreeProcessor(dedupConf);

						if (emitOutput(treeProcessor.compare(pivot, curr), idPivot, idCurr, context)) {
							icc.connect(i, j);
						}
					}
				}
			}
		}
	}

	public Object getJavaValue(Row row, int pos) {
		DataType dt = row.schema().fields()[pos].dataType();
		if (dt instanceof StringType) {
			return row.getString(pos);
		} else if (dt instanceof ArrayType) {
			return row.getList(pos);
		}

		return null;
	}

	private boolean emitOutput(final boolean result, final String idPivot, final String idCurr,
		final Reporter context) {

		if (result) {
			if (idPivot.compareTo(idCurr) <= 0) {
				writeSimilarity(context, idPivot, idCurr);
			} else {
				writeSimilarity(context, idCurr, idPivot);
			}
			context.incrementCounter(dedupConf.getWf().getEntityType(), "dedupSimilarity (x2)", 1);
		} else {
			context.incrementCounter(dedupConf.getWf().getEntityType(), "d < " + dedupConf.getWf().getThreshold(), 1);
		}

		return result;
	}

	private boolean mustSkip(final String idPivot) {
		return dedupConf.getWf().getSkipList().contains(getNsPrefix(idPivot));
	}

	private String getNsPrefix(final String id) {
		return StringUtils.substringBetween(id, "|", "::");
	}

	private void writeSimilarity(final Reporter context, final String from, final String to) {
		final String type = dedupConf.getWf().getEntityType();

		context.emit(type, from, to);
	}
}