package edu.unc.genomics.visualization;

import java.io.Serializable;
import java.util.Collection;

import org.apache.commons.math.stat.clustering.Clusterable;

/**
 * @author timpalpant
 * Holds a row of data for the KMeans program
 */
class KMeansRow implements Clusterable<KMeansRow>, Serializable {

	private static final long serialVersionUID = -323598431692368500L;
	
	private final String id;
	/** Point coordinates. */
  private final float[] point;

	/**
   * Build an instance wrapping an float array.
   * <p>The wrapped array is referenced, it is <em>not</em> copied.</p>
   * @param point the n-dimensional point in integer space
   */
	public KMeansRow(final String id, final float[] point) {
		this.point = point;
		this.id = id;
	}

  /**
   * Get the n-dimensional point in float space.
   * @return a reference (not a copy!) to the wrapped array
   */
  public float[] getPoint() {
      return point;
  }

  /** {@inheritDoc} */
  public double distanceFrom(final KMeansRow p) {
  		double sumSquares = 0;
  		float[] otherPoint = p.getPoint();
  		for (int i = 0; i < point.length; i++) {
  			sumSquares += Math.pow(point[i]-otherPoint[i], 2);
  		}
      return Math.sqrt(sumSquares);
  }

  /** {@inheritDoc} */
  public KMeansRow centroidOf(final Collection<KMeansRow> points) {
      float[] centroid = new float[getPoint().length];
      for (KMeansRow p : points) {
          for (int i = 0; i < centroid.length; i++) {
              centroid[i] += p.getPoint()[i];
          }
      }
      for (int i = 0; i < centroid.length; i++) {
          centroid[i] /= points.size();
      }
      return new KMeansRow(id, centroid);
  }

  /** {@inheritDoc} */
  @Override
  public boolean equals(final Object other) {
      if (!(other instanceof KMeansRow)) {
          return false;
      }
      final float[] otherPoint = ((KMeansRow) other).getPoint();
      if (point.length != otherPoint.length) {
          return false;
      }
      for (int i = 0; i < point.length; i++) {
          if (point[i] != otherPoint[i]) {
              return false;
          }
      }
      return true;
  }

  /** {@inheritDoc} */
  @Override
  public int hashCode() {
      int hashCode = 0;
      for (Float i : point) {
          hashCode += i.hashCode() * 13 + 7;
      }
      return hashCode;
  }

  /**
   * {@inheritDoc}
   * @since 2.1
   */
  @Override
  public String toString() {
      final StringBuilder buff = new StringBuilder(id);
      for (float value : getPoint()) {
      	buff.append("\t").append(value);
      }
      return buff.toString();
  }

	/**
	 * @return the id
	 */
	public String getId() {
		return id;
	}

}