Test & Question

type BankSelection = {
  totalCount: number;                // celkový počet otázok pre študenta (napr. 20)
  byTag?: BankSelectionByTag[];      // voliteľné váhované rozdelenie podľa tagov
};
 
type BankSelectionByTag = {
  tag: string;                       // napr. "financovanie"
  count: number;                     // koľko otázok z tohto tagu (napr. 5)
};

type Answer = {
  id: string;          // stable ID v rámci otázky (UUID alebo nanoid)
  text: string;        // text odpovede (Markdown)
  isCorrect: boolean;  // pre single_choice presne 1 true; pre multiple_choice 1+
};

db.tests.createIndex({ courseId: 1 });
db.tests.createIndex({ placement: 1, placementOwnerId: 1 });
db.questions.createIndex({ testId: 1, orderIndex: 1 });
db.questions.createIndex({ bankId: 1 });
db.questions.createIndex({ courseId: 1, tags: 1 });
db.questions.createIndex({ courseId: 1, difficulty: 1 });

type SubmittedAnswer = {
  questionId: ObjectId;
  selectedAnswerIds?: string[];   // single/multiple
  textAnswer?: string;             // short_text
  isCorrect: boolean;
  pointsEarned: number;            // Question.weight × correctness
};

async function startAttempt(testId: ObjectId, enrollmentId: ObjectId): Promise<TestAttempt> {
  const test = await loadTest(testId);
  const previousAttempts = await countAttempts(testId, enrollmentId);
  
  // 1. Validácie
  if (test.maxAttempts && previousAttempts >= test.maxAttempts) {
    throw new Error('max_attempts_reached');
  }
  if (test.cooldownMinutes) {
    const lastAttempt = await getLastAttempt(testId, enrollmentId);
    if (lastAttempt && minutesSince(lastAttempt.submittedAt) < test.cooldownMinutes) {
      throw new Error('cooldown_active');
    }
  }
  
  // 2. Výber otázok
  let selectedQuestionIds: ObjectId[];
  if (test.selectionMode === 'fixed') {
    selectedQuestionIds = [...test.fixedQuestions];
  } else {
    selectedQuestionIds = sampleFromBank(test.bankQuestions, test.bankSelection);
  }
  
  // 3. Randomizácia poradia otázok
  const questionOrder = test.randomizeQuestionOrder
    ? shuffle(selectedQuestionIds)
    : selectedQuestionIds;
  
  // 4. Randomizácia poradia odpovedí
  const answerOrders: Record<string, string[]> = {};
  for (const qId of questionOrder) {
    const question = await loadQuestion(qId);
    if (question.answers && test.randomizeAnswerOrder) {
      answerOrders[qId.toString()] = shuffle(question.answers.map((a) => a.id));
    } else if (question.answers) {
      answerOrders[qId.toString()] = question.answers.map((a) => a.id);
    }
  }
  
  // 5. Vytvor TestAttempt
  return await createTestAttempt({
    testId,
    enrollmentId,
    studentId: ...,
    attemptNumber: previousAttempts + 1,
    selectedQuestionIds,
    questionOrder,
    answerOrders,
    startedAt: new Date(),
    idempotencyKey: `${enrollmentId}:${testId}:${previousAttempts + 1}`,
  });
}
 
function sampleFromBank(bank: ObjectId[], rules: BankSelection): ObjectId[] {
  // 1. Načítaj questions z banku s tags
  const questions = await loadQuestionsWithTags(bank);
  const result: ObjectId[] = [];
  
  // 2. Pre každý byTag rule náhodne vyber count otázok
  const usedIds = new Set<string>();
  for (const rule of rules.byTag ?? []) {
    const candidates = questions.filter((q) => 
      q.tags?.includes(rule.tag) && !usedIds.has(q._id.toString())
    );
    const sampled = shuffle(candidates).slice(0, rule.count);
    if (sampled.length < rule.count) {
      throw new Error(`not_enough_questions_for_tag: ${rule.tag}`);
    }
    sampled.forEach((q) => { result.push(q._id); usedIds.add(q._id.toString()); });
  }
  
  // 3. Doplň zvyšok náhodne z untagged
  const remaining = rules.totalCount - result.length;
  if (remaining > 0) {
    const candidates = questions.filter((q) => !usedIds.has(q._id.toString()));
    const sampled = shuffle(candidates).slice(0, remaining);
    if (sampled.length < remaining) {
      throw new Error('not_enough_questions_in_bank');
    }
    sampled.forEach((q) => { result.push(q._id); });
  }
  
  return result;
}

db.test_attempts.createIndex({ enrollmentId: 1, testId: 1, attemptNumber: 1 }, { unique: true });
db.test_attempts.createIndex({ idempotencyKey: 1 }, { unique: true });
db.test_attempts.createIndex({ studentId: 1, submittedAt: -1 });
db.test_attempts.createIndex({ testId: 1, passed: 1 });   // pre štatistiky

{
  "_id": "ObjectId('test_module_1_4')",
  "placement": "module",
  "placementOwnerId": "ObjectId('module_1_4')",
  "courseId": "ObjectId('course_sportovy_manazment')",
  "title": "Záverečný test — Financovanie športu (Základy)",
  "description": "10 otázok pokrývajúcich obsah modulu. Na úspešné absolvovanie potrebuješ 70 %.",
  "selectionMode": "fixed",
  "fixedQuestions": [
    "ObjectId('q1')", "ObjectId('q2')", "...10 otázok..."
  ],
  "randomizeQuestionOrder": true,
  "randomizeAnswerOrder": true,
  "passingScore": 0.7,
  "timeLimitSec": 1200,
  "maxAttempts": 3,
  "cooldownMinutes": 30,
  "showAnswersAfter": "after_pass",
  "version": 1,
  "createdAt": "2026-08-15T10:00:00Z",
  "updatedAt": "2026-09-01T08:00:00Z"
}

{
  "_id": "ObjectId('test_level_1')",
  "placement": "level",
  "placementOwnerId": "ObjectId('level_1')",
  "courseId": "ObjectId('course_sportovy_manazment')",
  "title": "Medzitest — Základy",
  "description": "20 otázok zo všetkých 10 tém Levelu. Náhodný výber z banky 100 otázok.",
  "selectionMode": "random_sample",
  "bankQuestions": [
    "...100 otázok IDs..."
  ],
  "bankSelection": {
    "totalCount": 20,
    "byTag": [
      { "tag": "prostredie-sportu", "count": 2 },
      { "tag": "pravne-predpisy", "count": 2 },
      { "tag": "financne-pojmy", "count": 2 },
      { "tag": "financovanie", "count": 2 },
      { "tag": "organizacia-riadenie", "count": 2 },
      { "tag": "zainteresovane-strany", "count": 2 },
      { "tag": "podujatia", "count": 2 },
      { "tag": "socialno-psychologicke", "count": 2 },
      { "tag": "marketing", "count": 2 },
      { "tag": "infrastruktura", "count": 2 }
    ]
  },
  "randomizeQuestionOrder": true,
  "randomizeAnswerOrder": true,
  "passingScore": 0.7,
  "timeLimitSec": 2400,
  "maxAttempts": 3,
  "cooldownMinutes": 60,
  "showAnswersAfter": "after_pass",
  "version": 1,
  "createdAt": "2026-08-15T10:00:00Z",
  "updatedAt": "2026-09-01T08:00:00Z"
}