refactor(ui): reorganize collection menus and sorting

- move MainMenu to the root ui package
- add CurrentCollectionMenu for current collection operations
- move sorting components under collection/sorting
- add CollectionFileSaveWindow for saving collections to file
- update imports and menu delegation

app/src/main/java/ru/project/ui/collection/CurrentCollectionMenu.java

@@ -0,0 +1,64 @@
+package ru.project.ui.collection;
+
+import com.googlecode.lanterna.gui2.ActionListBox;
+import com.googlecode.lanterna.gui2.WindowBasedTextGUI;
+import ru.project.model.AppState;
+import ru.project.ui.base.BaseModalWindow;
+import ru.project.ui.collection.sorting.SortCollectionMenu;
+import ru.project.ui.common.CollectionDisplayWindow;
+import ru.project.ui.common.CollectionFileSaveWindow;
+import ru.project.ui.common.MessageWindow;
+
+public class CurrentCollectionMenu extends BaseModalWindow {
+
+  private final AppState state;
+
+  private final SortCollectionMenu sortCollectionMenu;
+
+  public CurrentCollectionMenu(WindowBasedTextGUI gui, AppState state) {
+
+    super("Меню текущей коллекции", gui);
+
+    this.state = state;
+
+    this.sortCollectionMenu = new SortCollectionMenu(gui, state);
+
+    ActionListBox menu = new ActionListBox();
+
+    menu.addItem("Показать коллекцию", this::showCurrentCollection);
+
+    menu.addItem("Сохранить коллекцию в файл", this::saveCurrentCollection);
+
+    menu.addItem("Сортировать коллекцию", sortCollectionMenu::showModal);
+
+    menu.addItem("Поиск элемента в коллекции", this::searchCollection);
+
+    menu.addItem("Подсчёт количества вхождений элемента", this::countOccurrences);
+
+    menu.addItem("Выйти", this::close);
+
+    setComponent(menu);
+  }
+
+  private void showCurrentCollection() {
+    CollectionDisplayWindow window = new CollectionDisplayWindow(gui, state.getMainCollection());
+
+    window.showModal();
+  }
+
+  private void saveCurrentCollection() {
+    CollectionFileSaveWindow window = new CollectionFileSaveWindow(gui, state.getMainCollection());
+
+    window.showModal();
+  }
+
+  private void searchCollection() {
+    // TODO
+    MessageWindow.showModal(gui, "Не реализовано.");
+  }
+
+  private void countOccurrences() {
+    // TODO
+    MessageWindow.showModal(gui, "Не реализовано.");
+  }
+}

app/src/main/java/ru/project/ui/collection/sorting/NormalSortSettingsWindow.java

@@ -0,0 +1,45 @@
+package ru.project.ui.collection.sorting;
+
+import com.googlecode.lanterna.gui2.ActionListBox;
+import com.googlecode.lanterna.gui2.Button;
+import com.googlecode.lanterna.gui2.LinearLayout;
+import com.googlecode.lanterna.gui2.Panel;
+import com.googlecode.lanterna.gui2.WindowBasedTextGUI;
+import java.util.function.Consumer;
+import ru.project.ui.base.BaseModalWindow;
+
+public class NormalSortSettingsWindow extends BaseModalWindow {
+
+  private final Consumer<SortField> onSortFieldSelected;
+
+  public NormalSortSettingsWindow(WindowBasedTextGUI gui, Consumer<SortField> onSortFieldSelected) {
+
+    super("Обычная сортировка", gui);
+
+    this.onSortFieldSelected = onSortFieldSelected;
+
+    Panel panel = new Panel();
+    panel.setLayoutManager(new LinearLayout());
+
+    ActionListBox menu = new ActionListBox();
+
+    menu.addItem("Сортировать по номеру группы", () -> selectSortField(SortField.GROUP_NUMBER));
+
+    menu.addItem("Сортировать по среднему баллу", () -> selectSortField(SortField.AVERAGE_GRADE));
+
+    menu.addItem(
+        "Сортировать по номеру зачётной книжки",
+        () -> selectSortField(SortField.RECORD_BOOK_NUMBER));
+
+    panel.addComponent(menu);
+
+    panel.addComponent(new Button("Выйти", this::close));
+
+    setComponent(panel);
+  }
+
+  private void selectSortField(SortField sortField) {
+    onSortFieldSelected.accept(sortField);
+    close();
+  }
+}

app/src/main/java/ru/project/ui/collection/sorting/ParitySortSettingsWindow.java

@@ -0,0 +1,24 @@
+package ru.project.ui.collection.sorting;
+
+import com.googlecode.lanterna.gui2.Button;
+import com.googlecode.lanterna.gui2.Label;
+import com.googlecode.lanterna.gui2.LinearLayout;
+import com.googlecode.lanterna.gui2.Panel;
+import com.googlecode.lanterna.gui2.WindowBasedTextGUI;
+import ru.project.ui.base.BaseModalWindow;
+
+public class ParitySortSettingsWindow extends BaseModalWindow {
+
+  public ParitySortSettingsWindow(WindowBasedTextGUI gui) {
+    super("Настройка сортировки по чётности", gui);
+
+    Panel panel = new Panel();
+    panel.setLayoutManager(new LinearLayout());
+
+    panel.addComponent(new Label("Сортировка выполняется по номеру зачётной книжки."));
+
+    panel.addComponent(new Button("Назад", this::close));
+
+    setComponent(panel);
+  }
+}

app/src/main/java/ru/project/ui/collection/sorting/SortCollectionMenu.java

@@ -0,0 +1,126 @@
+package ru.project.ui.collection.sorting;
+
+import com.googlecode.lanterna.gui2.Button;
+import com.googlecode.lanterna.gui2.Label;
+import com.googlecode.lanterna.gui2.LinearLayout;
+import com.googlecode.lanterna.gui2.Panel;
+import com.googlecode.lanterna.gui2.WindowBasedTextGUI;
+import ru.project.model.AppState;
+import ru.project.ui.base.BaseModalWindow;
+import ru.project.ui.common.MessageWindow;
+
+public class SortCollectionMenu extends BaseModalWindow {
+
+  private final AppState state;
+
+  private final Label sortMethodLabel;
+  private final Label sortFieldLabel;
+
+  private final SortMethodSelectionWindow sortMethodSelectionWindow;
+  private final NormalSortSettingsWindow normalSortSettingsWindow;
+  private final ParitySortSettingsWindow paritySortSettingsWindow;
+
+  private SortMethod selectedSortMethod;
+  private SortField selectedSortField;
+
+  public SortCollectionMenu(WindowBasedTextGUI gui, AppState state) {
+
+    super("Меню сортировки текущей коллекции", gui);
+
+    this.state = state;
+    this.selectedSortMethod = SortMethod.NORMAL;
+    this.selectedSortField = SortField.GROUP_NUMBER;
+
+    Panel panel = new Panel();
+    panel.setLayoutManager(new LinearLayout());
+
+    this.sortMethodLabel = new Label("Способ сортировки: " + getSortMethodName(selectedSortMethod));
+
+    this.sortFieldLabel = new Label("Сортировать по: " + getSortFieldName(selectedSortField));
+
+    this.sortMethodSelectionWindow =
+        new SortMethodSelectionWindow(
+            gui,
+            sortMethod -> {
+              selectedSortMethod = sortMethod;
+
+              sortMethodLabel.setText(
+                  "Способ сортировки: " + getSortMethodName(selectedSortMethod));
+            });
+
+    this.normalSortSettingsWindow =
+        new NormalSortSettingsWindow(
+            gui,
+            sortField -> {
+              selectedSortField = sortField;
+            });
+
+    this.paritySortSettingsWindow = new ParitySortSettingsWindow(gui);
+
+    panel.addComponent(sortMethodLabel);
+    panel.addComponent(sortFieldLabel);
+
+    panel.addComponent(new Button("Выбрать способ сортировки", this::selectSortMethod));
+
+    panel.addComponent(
+        new Button("Настроить текущий способ сортировки", this::setupCurrentSortMethod));
+
+    panel.addComponent(new Button("Сортировать текущую коллекцию", this::sortCurrentCollection));
+
+    panel.addComponent(new Button("Выйти", this::close));
+
+    setComponent(panel);
+  }
+
+  private void setupCurrentSortMethod() {
+    switch (selectedSortMethod) {
+      case NORMAL -> normalSortSettingsWindow.showModal();
+
+      case PARITY -> paritySortSettingsWindow.showModal();
+    }
+  }
+
+  private void selectSortMethod() {
+    sortMethodSelectionWindow.showModal();
+  }
+
+  private void sortCurrentCollection() {
+    if (state.getMainCollection() == null || state.getMainCollection().isEmpty()) {
+
+      MessageWindow.showModal(gui, "Текущая коллекция пуста.");
+
+      return;
+    }
+
+    switch (selectedSortMethod) {
+      case NORMAL -> sortNormally();
+
+      case PARITY -> sortByParity();
+    }
+  }
+
+  private void sortNormally() {
+    // TODO
+    MessageWindow.showModal(gui, "Обычная сортировка не реализована.");
+  }
+
+  private void sortByParity() {
+    // TODO
+    MessageWindow.showModal(gui, "Сортировка по чётности не реализована.");
+  }
+
+  private String getSortMethodName(SortMethod sortMethod) {
+    return switch (sortMethod) {
+      case NORMAL -> "Обычная сортировка";
+      case PARITY -> "Сортировка по чётности";
+    };
+  }
+
+  private String getSortFieldName(SortField sortField) {
+    return switch (sortField) {
+      case GROUP_NUMBER -> "номеру группы";
+      case AVERAGE_GRADE -> "среднему баллу";
+      case RECORD_BOOK_NUMBER -> "номеру зачётной книжки";
+    };
+  }
+}

app/src/main/java/ru/project/ui/collection/sorting/SortField.java

@@ -0,0 +1,7 @@
+package ru.project.ui.collection.sorting;
+
+public enum SortField {
+  GROUP_NUMBER,
+  AVERAGE_GRADE,
+  RECORD_BOOK_NUMBER
+}

app/src/main/java/ru/project/ui/collection/sorting/SortMethod.java

@@ -0,0 +1,6 @@
+package ru.project.ui.collection.sorting;
+
+public enum SortMethod {
+  NORMAL,
+  PARITY
+}

app/src/main/java/ru/project/ui/collection/sorting/SortMethodSelectionWindow.java

@@ -0,0 +1,34 @@
+package ru.project.ui.collection.sorting;
+
+import com.googlecode.lanterna.gui2.ActionListBox;
+import com.googlecode.lanterna.gui2.WindowBasedTextGUI;
+import java.util.function.Consumer;
+import ru.project.ui.base.BaseModalWindow;
+
+public class SortMethodSelectionWindow extends BaseModalWindow {
+
+  private final Consumer<SortMethod> onSortMethodSelected;
+
+  public SortMethodSelectionWindow(
+      WindowBasedTextGUI gui, Consumer<SortMethod> onSortMethodSelected) {
+
+    super("Выбрать способ сортировки", gui);
+
+    this.onSortMethodSelected = onSortMethodSelected;
+
+    ActionListBox menu = new ActionListBox();
+
+    menu.addItem("Обычная сортировка", () -> selectSortMethod(SortMethod.NORMAL));
+
+    menu.addItem("Сортировка по чётности", () -> selectSortMethod(SortMethod.PARITY));
+
+    menu.addItem("Выйти", this::close);
+
+    setComponent(menu);
+  }
+
+  private void selectSortMethod(SortMethod sortMethod) {
+    onSortMethodSelected.accept(sortMethod);
+    close();
+  }
+}