Convert top navigation bar to sidebar with expandable schedule submenu

src/main/java/org/example/se302/controller/MainController.java

@@ -1,35 +1,57 @@
 package org.example.se302.controller;
 
 import javafx.fxml.FXML;
+import javafx.fxml.FXMLLoader;
 import javafx.scene.control.Button;
 import javafx.scene.control.Label;
-import javafx.scene.control.Tab;
-import javafx.scene.control.TabPane;
+import javafx.scene.layout.StackPane;
+import javafx.scene.layout.VBox;
+import javafx.scene.Node;
 import org.example.se302.service.DataManager;
 
+import java.io.IOException;
+
 /**
  * Main controller for the application window.
- * Manages the TabPane, status bar, and theme toggling.
+ * Manages the sidebar navigation, content area, status bar, and theme toggling.
  */
 public class MainController {
 
     @FXML
-    private TabPane mainTabPane;
+    private VBox sidebar;
 
     @FXML
-    private Tab importTab;
+    private StackPane contentArea;
 
     @FXML
-    private Tab studentsTab;
+    private Button importBtn;
 
     @FXML
-    private Tab coursesTab;
+    private Button studentsBtn;
 
     @FXML
-    private Tab classroomsTab;
+    private Button coursesBtn;
 
     @FXML
-    private Tab scheduleTab;
+    private Button classroomsBtn;
+
+    @FXML
+    private Button scheduleBtn;
+
+    @FXML
+    private VBox scheduleSubMenu;
+
+    @FXML
+    private Button calendarBtn;
+
+    @FXML
+    private Button studentScheduleBtn;
+
+    @FXML
+    private Button courseScheduleBtn;
+
+    @FXML
+    private Button classroomScheduleBtn;
 
     @FXML
     private Label statusLabel;
@@ -39,36 +61,62 @@ public class MainController {
 
     private DataManager dataManager;
     private boolean isDarkMode = false;
+    private boolean scheduleMenuOpen = false;
+
+    // Cached views
+    private Node importView;
+    private Node studentsView;
+    private Node coursesView;
+    private Node classroomsView;
+    private Node calendarView;
+    private Node studentScheduleView;
+    private Node courseScheduleView;
+    private Node classroomScheduleView;
+
+    private Button activeButton;
 
     @FXML
     public void initialize() {
         dataManager = DataManager.getInstance();
 
-        // Initially disable data tabs until import is complete
-        studentsTab.setDisable(true);
-        coursesTab.setDisable(true);
-        classroomsTab.setDisable(true);
-        scheduleTab.setDisable(true);
+        // Pre-load main views
+        importView = loadView("import-view.fxml");
+        studentsView = loadView("students-view.fxml");
+        coursesView = loadView("courses-view.fxml");
+        classroomsView = loadView("classrooms-view.fxml");
+
+        // Pre-load schedule views to eliminate delay
+        calendarView = loadView("schedule-calendar-view.fxml");
+        studentScheduleView = loadView("schedule-student-view.fxml");
+        courseScheduleView = loadView("schedule-course-view.fxml");
+        classroomScheduleView = loadView("schedule-classroom-view.fxml");
+
+        // Show import view initially
+        contentArea.getChildren().clear();
+        contentArea.getChildren().add(importView);
+
+        // Set import as active by default
+        setActiveButton(importBtn);
 
         updateStatusBar();
 
-        // Listen for data changes to automatically enable tabs
+        // Listen for data changes to automatically enable buttons
         dataManager.getStudents().addListener(
                 (javafx.collections.ListChangeListener<org.example.se302.model.Student>) c -> {
                     if (dataManager.hasData()) {
-                        enableDataTabs();
+                        enableDataButtons();
                     }
                 });
     }
 
     /**
-     * Enable data tabs after successful import.
+     * Enable data buttons after successful import.
      */
-    public void enableDataTabs() {
-        studentsTab.setDisable(false);
-        coursesTab.setDisable(false);
-        classroomsTab.setDisable(false);
-        scheduleTab.setDisable(false);
+    public void enableDataButtons() {
+        studentsBtn.setDisable(false);
+        coursesBtn.setDisable(false);
+        classroomsBtn.setDisable(false);
+        scheduleBtn.setDisable(false);
         updateStatusBar();
     }
 
@@ -87,12 +135,105 @@ public class MainController {
         }
     }
 
+    /**
+     * Set the active button style
+     */
+    private void setActiveButton(Button button) {
+        if (activeButton != null) {
+            activeButton.getStyleClass().remove("sidebar-button-active");
+        }
+        activeButton = button;
+        activeButton.getStyleClass().add("sidebar-button-active");
+    }
+
+    /**
+     * Show a view in the content area
+     */
+    private void showView(Node view, Button button) {
+        contentArea.getChildren().clear();
+        contentArea.getChildren().add(view);
+        setActiveButton(button);
+    }
+
+    /**
+     * Load a view from FXML
+     */
+    private Node loadView(String fxmlPath) {
+        try {
+            FXMLLoader loader = new FXMLLoader(
+                    getClass().getResource("/org/example/se302/view/" + fxmlPath));
+            return loader.load();
+        } catch (IOException e) {
+            e.printStackTrace();
+            return new Label("Error loading view: " + fxmlPath);
+        }
+    }
+
+    @FXML
+    private void onShowImport() {
+        showView(importView, importBtn);
+    }
+
+    @FXML
+    private void onShowStudents() {
+        showView(studentsView, studentsBtn);
+    }
+
+    @FXML
+    private void onShowCourses() {
+        showView(coursesView, coursesBtn);
+    }
+
+    @FXML
+    private void onShowClassrooms() {
+        showView(classroomsView, classroomsBtn);
+    }
+
+    /**
+     * Toggle schedule submenu visibility and show Calendar View by default
+     */
+    @FXML
+    private void onToggleScheduleMenu() {
+        if (!scheduleMenuOpen) {
+            // First time opening - show Calendar View and expand submenu
+            scheduleMenuOpen = true;
+            scheduleSubMenu.setVisible(true);
+            scheduleSubMenu.setManaged(true);
+            showView(calendarView, calendarBtn);
+        } else {
+            // Toggle submenu visibility
+            scheduleMenuOpen = false;
+            scheduleSubMenu.setVisible(false);
+            scheduleSubMenu.setManaged(false);
+        }
+    }
+
+    @FXML
+    private void onShowCalendar() {
+        showView(calendarView, calendarBtn);
+    }
+
+    @FXML
+    private void onShowStudentSchedule() {
+        showView(studentScheduleView, studentScheduleBtn);
+    }
+
+    @FXML
+    private void onShowCourseSchedule() {
+        showView(courseScheduleView, courseScheduleBtn);
+    }
+
+    @FXML
+    private void onShowClassroomSchedule() {
+        showView(classroomScheduleView, classroomScheduleBtn);
+    }
+
     /**
      * Toggle between light and dark themes.
      */
     @FXML
     private void onToggleTheme() {
-        var root = mainTabPane.getScene().getRoot();
+        var root = contentArea.getScene().getRoot();
         var styleClass = root.getStyleClass();
 
         if (isDarkMode) {