package org.apache.samoa.evaluation;

/*
 * #%L
 * SAMOA
 * %%
 * Copyright (C) 2014 - 2018 Łukasz Ławniczak
 * %%
 * 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%
 */


public class WindowEstimator {
    protected double[] window;

    protected int posWindow;

    protected int lenWindow;

    protected int SizeWindow;

    protected double sum;

    public WindowEstimator(int sizeWindow) {
      window = new double[sizeWindow];
      SizeWindow = sizeWindow;
      posWindow = 0;
      lenWindow = 0;
    }

    public void add(double value) {
      sum -= window[posWindow];
      sum += value;
      window[posWindow] = value;
      posWindow++;
      if (posWindow == SizeWindow) {
        posWindow = 0;
      }
      if (lenWindow < SizeWindow) {
        lenWindow++;
      }
    }

    public double total() {
      return sum;
    }

    public double length() {
      return lenWindow;
    }
    
    public double estimation() {
        return sum / lenWindow;
    }
}