openct-tasks/_common/modules/pemFioi/quiz2/grader.js

(function() {


    function scoreCalculator(score_settings, nb_total) {

        var nb_valid = 0;
        var nb_mistakes = 0;

        return {

            addAnswer: function(answer_score) {
                if(typeof answer_score === 'boolean') {
                    nb_valid += answer_score ? 1 : 0;
                    nb_mistakes += answer_score ? 0 : 1;
                } else {
                    answer_score = parseFloat(answer_score) || 0;
                    nb_valid += answer_score;
                    nb_mistakes += answer_score > 0 ? 0 : 1;
                }
            },

            getScore: function() {
                if(score_settings) {
                    var score = (nb_valid * score_settings.maxScore
                               + nb_mistakes * score_settings.minScore
                               + (nb_total - nb_valid - nb_mistakes) * score_settings.noScore) / nb_total;
                } else {
                    var score = nb_valid / nb_total;
                }
                score = Math.round(score);
                return score;
            }
        }

    }




    function graderDataEnumerator(grader_data, versions) {

        return {
            each: function(callback) {
                for (var i = 0; i < grader_data.length; i++) {
                    var answer_grader_data = grader_data[i];
                    if(versions && i in versions) {
                        answer_grader_data = answer_grader_data[versions[i]];
                    }
                    callback(answer_grader_data, i);
                }
            }
        }

    }




    function getAnswerGrader(grader) {


        function gradeAnswerArray(given_answer, correct_answer, messages) {
            var res = {
                score: true,
                feedback: {
                    correct_answer: correct_answer,
                    mistakes: [],
                    messages: messages
                }
            }
            for(var i=0; i<given_answer.length; i++) {
                var correct = correct_answer.indexOf(given_answer[i]) !== -1;
                res.score = res.score && correct;
                if(!correct) {
                    res.feedback.mistakes.push(given_answer[i]);
                }
            }
            if(given_answer.length != correct_answer.length) {
                res.score = false;
            }
            return res;
        }


        function gradeAnswerArrayStrict(given_answer, correct_answer, messages) {
            var res = {
                score: true,
                feedback: {
                    correct_answer: correct_answer,
                    mistakes: [],
                    messages: messages
                }
            }
            for(var i=0; i<given_answer.length; i++) {
                var correct = correct_answer[i] === given_answer[i];
                res.score = res.score && correct;
                res.feedback.mistakes.push(correct ? null : given_answer[i]);
            }
            if(given_answer.length != correct_answer.length) {
                res.score = false;
            }
            return res;
        }



        var grader_types = {

            'function': function(answer) {
                // supposed to grade text input answers, so
                var fres = grader(answer[0]);
                if (typeof fres === 'object') {
                    // function return object
                    var res = {
                        score: 'score' in fres ? parseFloat(fres.score) || 0 : 0,
                        feedback: {
                            correct_answer: [],
                            mistakes: [],
                            messages: []
                        }
                    }
                    if(res.score == 0) {
                        res.feedback.mistakes = answer;
                    }
                    if('message' in fres && fres.message) {
                        res.feedback.messages = [fres.message];
                    }
                    if('correct_answer' in fres && fres.correct_answer) {
                        res.feedback.correct_answer = [fres.correct_answer];
                    }
                } else {
                    // use result as boolean
                    var res = {
                        score: !!fres,
                        feedback: {
                            correct_answer: [],
                            mistakes: [],
                            messages: []
                        }
                    }
                    if(!fres) {
                        res.feedback.mistakes = answer;
                    }
                }
                return res;
            },


            'array': function(answer) {
                return gradeAnswerArray(answer, grader, []);
            },


            'object': function(answer) {
                if(grader.strict) {
                    return gradeAnswerArrayStrict(answer, grader.value, grader.messages || []);
                }
                return gradeAnswerArray(answer, grader.value, grader.messages || []);
            },


            'scalar': function(answer) {
                var score = grader == answer[0];
                return {
                    score: score,
                    feedback: {
                        mistakes: answer,
                        messages: []
                    }
                }
            }
        }


        if(typeof grader === 'function') {
            return grader_types['function'];
        } else if (Array.isArray(grader)) {
            return grader_types['array'];
        } else if (typeof grader == 'object') {
            return grader_types['object'];
        }
        return grader_types['scalar'];

    }


    function grade(grader_data, answer, versions, score_settings) {
        var res = {
            score: 0,
            feedback: []
        }
        var calculator = scoreCalculator(score_settings, grader_data.length);
        graderDataEnumerator(grader_data, versions).each(function(answer_grader_data, idx) {
            var grader = getAnswerGrader(answer_grader_data);
            var grader_result = grader(answer[idx]);
            calculator.addAnswer(grader_result.score);
            res.feedback.push(grader_result.feedback);
        });
        res.score = calculator.getScore();
        //console.log(res)
        return res;
    };



    window.Quiz.grader.handler = grade;

})();