package simulator;

import org.apache.lucene.index.FieldInvertState;
import org.apache.lucene.search.similarities.TFIDFSimilarity;
import org.apache.lucene.util.BytesRef;

/**
 * Created by b.fpa on 20/05/15.
 */
public class CustomTFIDFSimilarity extends TFIDFSimilarity {

    protected boolean discountOverlaps = false;


    public boolean getDiscountOverlaps() {
        return discountOverlaps;
    }
    @Override
    public float coord(int i, int i1) {
        return 1;
    }

    @Override
    public float queryNorm(float v) {
        return (float) (1/Math.pow((double)v,2));
    }

    @Override
    public float tf(float v) {
        return 1; //(float)Math.sqrt(v);
    }

    @Override
    public float idf(long docFreq, long numDocs) {

        return (float)(Math.log(numDocs/(double)(docFreq+1)) + 1.0);
        //return 1;
    }

    @Override
    public float lengthNorm(FieldInvertState state) {
        final int numTerms;
        if (discountOverlaps)
            numTerms = state.getLength() - state.getNumOverlap();
        else
            numTerms = state.getLength();
        //return state.getBoost() * ((float) (1.0 / Math.sqrt(numTerms)));
        return (float) (1.0 / numTerms);
    }

    @Override
    public float decodeNormValue(long l) {
        return 1;
    }

    @Override
    public long encodeNormValue(float v) {
        return 1;
    }

    @Override
    public float sloppyFreq(int i) {
        return 1;
    }

    @Override
    public float scorePayload(int i, int i1, int i2, BytesRef bytesRef) {
        return 1;
    }
}