fix(retakenodes): Fix retake functionality, add Database functions

src/g2_2025_grade_calculator_pkg/launch/grade_calculator.launch.xml

@@ -7,5 +7,8 @@
     </node>
     <node pkg="g2_2025_grade_calculator_pkg" exec="grade_calculator"/>
     <node pkg="g2_2025_grade_calculator_pkg" exec="retake_grade_determinator"/>
-    <node pkg="g2_2025_grade_calculator_pkg" exec="retake_scheduler"/>
+    <node pkg="g2_2025_grade_calculator_pkg" exec="retake_scheduler">
+        <param name="retake_check_interval_sec" value="30"/>
+    </node>
+
 </launch>

src/g2_2025_grade_calculator_pkg/src/database/DatabaseManager.cpp

@@ -295,4 +295,23 @@ std::vector<StudentCourse> DatabaseManager::get_failed_course_results() {
     return failed_courses;
 }
 
+bool DatabaseManager::update_retake_status(const StudentCourse& sc) {
+    if (!is_connected()) {
+        return false;
+    }
+
+    try {
+        pqxx::work txn(*conn_);
+        txn.exec_params(SQL_UPDATE_RETAKE_STATUS, sc.student_name, sc.course_name);
+        txn.commit();
+        return true;
+    } catch (const pqxx::sql_error &e) {
+        RCLCPP_ERROR(logger_, "[DBS] 'update retake status' failed: %s", e.what());
+        return false;
+    } catch (const std::exception &e) {
+        RCLCPP_ERROR(logger_, "[DBS] database error: %s", e.what());
+        return false;
+    }
+}
+
 } // namespace assignments::one

src/g2_2025_grade_calculator_pkg/src/database/DatabaseManager.hpp

@@ -45,6 +45,7 @@ public:
 
     int get_final_course_grade(const StudentCourse& sc);
     std::vector<StudentCourse> get_failed_course_results();
+    bool update_retake_status(const StudentCourse &sc);
 
 private:
     rclcpp::Logger logger_;

src/g2_2025_grade_calculator_pkg/src/database/SQLQueries.hpp

@@ -36,6 +36,7 @@ static const std::string SQL_CREATE_COURSE_RESULTS = R"(
         exam_count INTEGER NOT NULL,
         final_grade INTEGER NOT NULL,
         is_retake BOOLEAN DEFAULT FALSE,
+        retake_done BOOLEAN DEFAULT FALSE,
         created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
     );
 )";
@@ -64,7 +65,7 @@ static const std::string SQL_SELECT_STUDENT_EXAM_RESULTS = R"(
 static const std::string SQL_SELECT_FAILED_COURSE_RESULTS = R"(
     SELECT fcr.student_name, fcr.course_name, fcr.final_grade, fcr.exam_count
     FROM final_course_results fcr
-    WHERE fcr.final_grade < 55 AND fcr.is_retake = FALSE
+    WHERE fcr.final_grade < 55 AND fcr.retake_done = FALSE
 )";
 
 static const std::string SQL_INSERT_EXAM_RESULT = R"(
@@ -89,6 +90,12 @@ static const std::string SQL_SELECT_STUDENT_LIST = R"(
     SELECT COUNT(*) FROM student_enrollments
 )";
 
+static const std::string SQL_UPDATE_RETAKE_STATUS = R"(
+    UPDATE final_course_results
+    SET retake_done = TRUE
+    WHERE student_name = $1 AND course_name = $2 AND retake_done = FALSE
+)";
+
 static const std::string SQL_INSERT_FINAL_COURSE_RESULT = R"(
     INSERT INTO final_course_results (student_name, course_name, exam_count, final_grade, is_retake)
     VALUES ($1, $2, $3, $4, $5)

src/g2_2025_grade_calculator_pkg/src/retake_grade_determinator/nodes/RetakeGradeDeterminator.cpp

@@ -90,6 +90,8 @@ void RetakeGradeDeterminator::grade_calculator_response(
         RCLCPP_WARN(this->get_logger(), "no database connection");
         return;
     }
+    data_map_[studentCourseCombo].clear();
+    db_manager_->update_retake_status(studentCourseCombo);
 
     auto response = future.get();