package pr02;

import java.text.DecimalFormat;

public class GradeList {
   
   private int[] grades;
   private double[] weights;
   private DecimalFormat twoPlaces;
   
   public GradeList(int size) {
      grades = new int[size];
      weights = new double[size];
      for (int i=0;i<size;i++) {
         grades[i] = 0;
         weights[i] = 1.0/size;
      }
      twoPlaces = new DecimalFormat("0.00");
   }
   
   public  boolean setGrade(int grade, int index) {
      if ((index < 1) || (index > grades.length))
         return false;
      grades[index-1] = grade;
      return true;
   }
   
   public int getGrade(int index) {
      if ((index < 1) || (index > grades.length))
         return -1;
      return grades[index-1];
   }
   
   public  boolean setWeight(double weight, int index) {
      if ((index < 1) || (index > grades.length))
         return false;
      if (weight < 0)
         return false;
      weights[index-1] = weight;
      return true;
   }
   
   public double getWeight(int index) {
      if ((index < 1) || (index > grades.length))
         return -1;
      return weights[index-1];
   }
   
   public double getAverage() {
      if (grades.length == 0)
         return 0.0;
      double sum = 0;
      for (int i=0;i<grades.length;i++)
         sum += grades[i];
      return sum/grades.length;
   }
   
   public double getWeightedAverage() {
      double sum = 0;
      for (int i=0;i<grades.length;i++)
         sum += grades[i]*weights[i];
      return sum;
   }
   
   public String toString() {
      if (grades.length == 0)
         return "\n\n";
      StringBuilder sb = new StringBuilder();
      sb.append(fourPlaces(grades[0]));
      for (int i=1;i<grades.length;i++)
         sb.append(" "+fourPlaces(grades[i]));
      sb.append("\n"+weightString(weights[0]));
      for (int i=1;i<weights.length;i++)
         sb.append(" "+weightString(weights[i]));
      sb.append("\n");
      return sb.toString();
   }
   
   public double getMaximum() {
      int pos;
      double max;
      for (pos = 0; pos<grades.length;pos++)
         if (weights[pos] != 0)
            break;
      if (pos == grades.length)
         return -1;
      max = grades[pos];
      for (int i=pos+1;i<grades.length;i++)
         if ((weights[i] !=0) && (max < grades[i]))
            max = grades[i];
      return max;
   }
   
   public double getMinimum() {
      int pos;
      double min;
      for (pos = 0; pos<grades.length;pos++)
         if (weights[pos] != 0)
            break;
      if (pos == grades.length)
         return -1;
      min = grades[pos];
      for (int i=pos+1;i<grades.length;i++)
         if ((weights[i] !=0) && (min > grades[i]))
            min = grades[i];
      return min;
   }
   
   private String fourPlaces(int n) {
      String s = "" + n;
      while (s.length() < 4)
         s = " " + s;
      return s;
   }
   
   private String weightString(double weight) {
      return twoPlaces.format(weight);
   }

}