package Presenter.Evaluation;

import Model.Line;
import Presenter.Algorithms.FastElementSelector;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;

/**
 * Implementierung verschiedener Algorithmen zur Berechnung von Ausgleichsgeraden.
 *
 * @Author: Armin Wolf
 * @Email: a_wolf28@uni-muenster.de
 * @Date: 07.09.2017.
 */
public class PercentageErrorBasedMeasure {


  private ArrayList<Double> percentageError;

  public PercentageErrorBasedMeasure(final LinkedList<Line> lines, Double m, Double b){

    ArrayList<Double> sampson =  new ArrayList<>();

    for (Line line : lines) {
      Double e = Math.pow(m * line.getM() - line.getB() + b, 2) / (Math.pow(m, 2) + 1);
      sampson.add(e);
    }

    percentageError = new ArrayList<>();

    for (int j=0;j<sampson.size();j++){
      percentageError.add(100 * sampson.get(j) / lines.get(j).getB());
    }
  }

  /* Percentege Error Approximation Measures */
  //verschiedene Eingaben für einen Alg.
  public Double mape(){
    double error = 0;

    for (Double d : percentageError) {
      error += Math.abs(d);
    }

    error /= percentageError.size();

    return error;
  }

  public Double mdape(){

    ArrayList<Double> abs = new ArrayList<>();

    for (Double d : percentageError){
        abs.add(Math.abs(d));
    }

    return FastElementSelector.randomizedSelect(abs, abs.size() * 0.5);
  }

  public Double rmspe(){
    double error = 0;

    for (Double d : percentageError) {
      error += Math.pow(d, 2);
    }

    error /= percentageError.size();

    return Math.sqrt(error);
  }

  public Double rmdspe(){
    ArrayList squares = new ArrayList();
    for (Double d : percentageError){
      squares.add(Math.pow(d,2));
    }

    return  Math.sqrt(FastElementSelector.randomizedSelect(squares, squares.size() * 0.5));
  }
}