package exercise.situation;

import java.io.*;
import java.util.*;

public class SituationEvaluator {	// Should implement Evaluator...

    public static SituationEvaluation
	evaluateSubmission(SituationSubmission submission) {

	String studentID = submission.getStudentID();
	String exerciseID = submission.getExerciseID();
	String submissionID = submission.getSubmissionID();

	try {
	    SituationSolution soln =
		SituationSolution.loadSolution(exerciseID);
	    Set solnSet = convertToSet(soln.getSituations());
	    Set subnSet = convertToSet(submission.getSituations());

	    // Does the student pass?
	    boolean passed;
	    int numReq = soln.getNumRequired();
	    if (numReq == SituationSolution.ALL_REQUIRED) {
		passed = solnSet.equals(subnSet);
	    } else {
		boolean sizeOK =
		    (numReq == SituationSolution.UNSPECIFIED_NUM_REQUIRED ||
		     numReq == subnSet.size());
		passed = sizeOK && solnSet.containsAll(subnSet);
	    }
	    SituationEvaluation eval = new SituationEvaluation(
		studentID, exerciseID, submissionID, passed);

	    // Save the evaluation to the persistent store.
	    try { SituationEvaluation.saveEvaluation(eval); }
	    catch (Exception e) {
		System.out.println(
			"SituationEvaluator.evaluateSubmission(): " +
			"Unable to save evaluation.");
	    }

	    // Return the evaluation as feedback.
	    return eval;

	} catch (IOException e) {
	    System.err.println("SituationEvaluator.evaluateSubmission(): " +
			       "Failed to load a solution; returning null.");
	    return null;
	}
    }

    protected static Set convertToSet(int[][] situations) {

	// Use Set and Vector to get rid of duplicate elements.
	Set set = new HashSet();
	for (int i = 0; i < situations.length; i++) {
	    Vector situation = new Vector();
	    for (int j = 0; j < situations[i].length; j++) {
		situation.add(new Integer(situations[i][j]));
	    }
	    set.add(situation);
	}
	return set;
    }
}