package swervelib.math;

import edu.wpi.first.util.DoubleCircularBuffer;

/**
 * A linear filter that does not calculate() each time a value is added to
 * the DoubleCircularBuffer.
 */
public class IMULinearMovingAverageFilter {

  /**
   * Circular buffer storing the current IMU readings
   */
  private final DoubleCircularBuffer m_inputs;
  /**
   * Gain on each reading.
   */
  private final double m_inputGain;
    
 /**
  * Construct a linear moving average fitler
  * @param bufferLength The number of values to average across
  */
  public IMULinearMovingAverageFilter(int bufferLength)
  {
    m_inputs = new DoubleCircularBuffer(bufferLength);
    m_inputGain = 1.0 / bufferLength;
  }

 /**
  * Add a value to the DoubleCircularBuffer
  * @param input Value to add
  */
  public void addValue(double input)
  {
    m_inputs.addFirst(input);
  }

 /**
  * Calculate the average of the samples in the buffer
  * @return The average of the values in the buffer
  */
  public double calculate()
  {
    double returnVal = 0.0;

      for(int i = 0; i < m_inputs.size(); i++)
      {
        returnVal += m_inputs.get(i) * m_inputGain;
      }
        
      return returnVal;
  }
}