/* -------------------------------------------------------- *
 * Aaron Morris                                             *
 * CS567                                                    *
 * Object-Oriented Event-Driven Simulation                  *
 *                                                          *
 * Extends Generic Stats class, tracking statistics based   *
 * on time, not instances.                                  *
 * -------------------------------------------------------- */
//package datasend;
import java.awt.*;

public class Averager {

	protected double lastTime;      // Last time Averager updated
        protected double last;          // Last value Averager updated with
	protected double sum;           // Running sum of all update values
	protected double sumsquared;    // Running sum of all values squared
	protected double max;           // Max value updated with to date
	protected double min;           // Min value updated with to date
	protected double n;             // Number of values updated with
	protected String title;         // Title of this statistics report

      // Constructor -- Initialize Title, and all members to 0
	public Averager(String Title)
	{
		this.title = Title;
                n = 0;
		last = 0;
		sum = 0;
		sumsquared = 0;
		min = 0;
		max = 0;
		lastTime = 0;
	}

      // Return number of samples that Averager has been updated with
      public double getNumSamples() { return n; }

      // Update method -- update the Averager for the increment of time
      // between lastTime and the Current Time with the Value sent in
	public void update(int Time, double Value)
	{
            // If this is the first value, min and max are the same
		if (n == 0)
		{
			min = Value;
			max = Value;
		}
		else if (Value < min)	{ min = Value; }   // New Min Value
		else if (Value > max)	{ max = Value; }   // New Max Value

            // Update for time interval from last update to this Time
		sum += Value*(Time-lastTime);
		last = Time;
		sumsquared += Value*Value * (Time - lastTime);
		lastTime = Time;
		n++;
	}

      // Print report of all the statistics gathered to the output object
	public void doReport(Report r)
	{
		double mean, ex2, variance;

            r.write(title);
            if (last == 0) 
		{
			r.write("    Time was 0, no stats to report");
			r.write(" ");
		}
            else
            {
                 mean = sum / last;
                 r.write("    observed for: " + this.last + " units of time");
                 r.write("    observations ranged from " +min+ " to " + max);
                 r.write("    mean is " + mean);
                 ex2 = sumsquared / last;
		 variance = ex2 - mean*mean;
                 r.write("    variance is " + variance);
                 r.write(" ");
            }
	}
}