package com.yahoo.labs.samoa.core;

/*
 * #%L
 * SAMOA
 * %%
 * Copyright (C) 2014 - 2015 Apache Software Foundation
 * %%
 * 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.
 * #L%
 */

import java.util.Arrays;

import com.google.common.primitives.Doubles;

public class DoubleVector implements java.io.Serializable {

  /**
	 * 
	 */
  private static final long serialVersionUID = 8243012708860261398L;

  private double[] doubleArray;

  public DoubleVector() {
    this.doubleArray = new double[0];
  }

  public DoubleVector(double[] toCopy) {
    this.doubleArray = new double[toCopy.length];
    System.arraycopy(toCopy, 0, this.doubleArray, 0, toCopy.length);
  }

  public DoubleVector(DoubleVector toCopy) {
    this(toCopy.getArrayRef());
  }

  public double[] getArrayRef() {
    return this.doubleArray;
  }

  public double[] getArrayCopy() {
    return Doubles.concat(this.doubleArray);
  }

  public int numNonZeroEntries() {
    int count = 0;
    for (double element : this.doubleArray) {
      if (Double.compare(element, 0.0) != 0) {
        count++;
      }
    }
    return count;
  }

  public void setValue(int index, double value) {
    if (index >= doubleArray.length) {
      this.doubleArray = Doubles.ensureCapacity(this.doubleArray, index + 1, 0);
    }
    this.doubleArray[index] = value;
  }

  public void addToValue(int index, double value) {
    if (index >= doubleArray.length) {
      this.doubleArray = Doubles.ensureCapacity(this.doubleArray, index + 1, 0);
    }
    this.doubleArray[index] += value;
  }

  public double sumOfValues() {
    double sum = 0.0;
    for (double element : this.doubleArray) {
      sum += element;
    }
    return sum;
  }

  public void getSingleLineDescription(StringBuilder out) {
    out.append("{");
    out.append(Doubles.join("|", this.doubleArray));
    out.append("}");
  }

  @Override
  public String toString() {
    return "DoubleVector [doubleArray=" + Arrays.toString(doubleArray) + "]";
  }

  @Override
  public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result + Arrays.hashCode(doubleArray);
    return result;
  }

  @Override
  public boolean equals(Object obj) {
    if (this == obj)
      return true;
    if (obj == null)
      return false;
    if (!(obj instanceof DoubleVector))
      return false;
    DoubleVector other = (DoubleVector) obj;
    return Arrays.equals(doubleArray, other.doubleArray);
  }
}