feat: improve student practice experience

apps/api/src/features/learning/routes.ts

@@ -226,6 +226,33 @@ function judgeAnswer(row: QuestionAnswerRow, selectedOptions: string[], answerTe
   return null;
 }
 
+function hasObjectiveAnswer(row: QuestionAnswerRow) {
+  return normalizeNumberArray(row.correct_option_indices).length > 0 ||
+    (row.correct_option_index !== null && row.correct_option_index !== undefined);
+}
+
+function optionalBodyBoolean(body: Record<string, unknown>, key: string): boolean | undefined {
+  const value = body[key];
+  if (value === undefined || value === null) return undefined;
+  if (typeof value === 'boolean') return value;
+  throw new HttpError(400, `${key} must be boolean`, 'INVALID_BOOLEAN_FIELD');
+}
+
+function resolveJudgedAnswer(
+  row: QuestionAnswerRow,
+  selectedOptions: string[],
+  answerText: string,
+  selfJudgedCorrect: boolean | undefined,
+) {
+  if (selfJudgedCorrect !== undefined) {
+    if (hasObjectiveAnswer(row)) {
+      throw new HttpError(400, 'Self judgment is only allowed for subjective questions', 'SELF_JUDGMENT_NOT_ALLOWED');
+    }
+    return selfJudgedCorrect;
+  }
+  return judgeAnswer(row, selectedOptions, answerText);
+}
+
 function optionalBodyString(body: Record<string, unknown>, key: string) {
   const value = body[key];
   return typeof value === 'string' && value.trim() ? value.trim() : null;
@@ -699,6 +726,7 @@ export async function submitAnswerRoute(ctx: RequestContext) {
   const questionId = requiredString(body, 'questionId');
   const selectedOptions = optionalStringArray(body, 'selectedOptions');
   const answerText = optionalString(body, 'answerText');
+  const selfJudgedCorrect = optionalBodyBoolean(body, 'selfJudgedCorrect');
   const practiceSessionId = optionalString(body, 'practiceSessionId') || null;
 
   const question = await queryOne<QuestionAnswerRow>(
@@ -717,10 +745,9 @@ export async function submitAnswerRoute(ctx: RequestContext) {
     throw new HttpError(404, 'Question not found', 'QUESTION_NOT_FOUND');
   }
 
-  const judged = judgeAnswer(question, selectedOptions, answerText);
-
   const result = await transaction(async client => {
     await assertAnswerSessionAccess(client, { tenantId, userId, practiceSessionId, questionId });
+    const judged = resolveJudgedAnswer(question, selectedOptions, answerText, selfJudgedCorrect);
 
     const answerResult = await client.query(
       `
@@ -774,7 +801,10 @@ export async function submitAnswerRoute(ctx: RequestContext) {
       [tenantId, userId, judged],
     );
 
-    return answerResult.rows[0];
+    return {
+      ...answerResult.rows[0],
+      selfJudged: selfJudgedCorrect !== undefined,
+    };
   });
 
   return { item: result };