package Prediction;

import Visual.*;
import Grades.*;
import Info.*;
import Reports.*;
import Assignments.*;

import java.util.Collection;
import java.util.List;

/*
 * A prediction object uses the class assignments, expected scores typed in by the user and the grading
 * scheme used by the teacher in order to accurately predict grading scenarios for students.
 *
 * This object is derived from Section 2.7 of the requirements.
 */
public abstract class Prediction {
   /** Stores the desired final grade typed in by the user. */
   long desiredGrade;
   /** Stores the predicted final grade after calculations. */
   long finalGrade;
   /** A complete collection of assignments scheduled for the class. */
   List<Assignment> classAssignments;
   
   /* 
    * This method calculates the final grade in a course based on the expected scores for all assignments.
    *
    */
   /*@
      requires
         // The scores for all upcoming assignments have been typed in.
         (\forall Assignment classAssignment;
            expectedAssignments.contains(classAssignment));
      ensures
         // The result of the function will equal the added weighted grade of all expected scores
         // typed in by the user.
         (\result == (\sum int i; (i >= 0) && (i < expectedAssignments.size()) ;
                        expectedAssignments.get(i).points.grade * expectedAssignments.get(i).points.weight));
   @*/
   abstract long calculateFinalGrade(List<Assignment> expectedAssignments);

   /*
    * This method calculates the scores needed on assignments in order to obtain the desired final grade.
    */
   /*@
      requires
         // The desired grade typed in by the user is non-negative.
         (desiredGrade >= 0);
      ensures
         // The sum of the returning list of grades is equal to the desired grade typed in by the user.
         (desiredGrade == (\sum int i; (i >= 0) && (i < \result.size()) ;
                             \result.get(i).grade * \result.get(i).weight));
   @*/
   abstract List<Grade> calculateScores();

   /*
    * This method calculates the maximum grade a student could obtain in a class.
    */
   /*@
      ensures
         // The result of the function will equal the sum of the maximum scores of all class assignments.
         (\result == (\sum int i; (i >= 0) && (i < classAssignments.size()) ;
                        classAssignments.get(i).points.maxPoints * 
                         classAssignments.get(i).points.weight));
   @*/
   abstract long getMaxGrade();
}