Merge branch 'master' into id-prefix-delete-command

src/main/java/seedu/address/ui/CommandBox.java

@@ -3,10 +3,13 @@
 import javafx.collections.ObservableList;
 import javafx.fxml.FXML;
 import javafx.scene.control.TextField;
+import javafx.scene.input.KeyCode;
+import javafx.scene.input.KeyEvent;
 import javafx.scene.layout.Region;
 import seedu.address.logic.commands.CommandResult;
 import seedu.address.logic.commands.exceptions.CommandException;
 import seedu.address.logic.parser.exceptions.ParseException;
+import seedu.address.ui.util.CommandHistory;
 
 /**
  * The UI component that is responsible for receiving user command inputs.
@@ -17,6 +20,7 @@ public class CommandBox extends UiPart<Region> {
     private static final String FXML = "CommandBox.fxml";
 
     private final CommandExecutor commandExecutor;
+    private final CommandHistory commandHistory;
 
     @FXML
     private TextField commandTextField;
@@ -27,8 +31,13 @@ public class CommandBox extends UiPart<Region> {
     public CommandBox(CommandExecutor commandExecutor) {
         super(FXML);
         this.commandExecutor = commandExecutor;
+        this.commandHistory = new CommandHistory();
+
         // calls #setStyleToDefault() whenever there is a change to the text of the command box.
         commandTextField.textProperty().addListener((unused1, unused2, unused3) -> setStyleToDefault());
+
+        // Add key press event handler
+        commandTextField.addEventFilter(KeyEvent.KEY_PRESSED, this::handleKeyPressed);
     }
 
     /**
@@ -43,12 +52,37 @@ private void handleCommandEntered() {
 
         try {
             commandExecutor.execute(commandText);
+            commandHistory.addCommand(commandText); // Add to history
             commandTextField.setText("");
         } catch (CommandException | ParseException e) {
             setStyleToIndicateCommandFailure();
         }
     }
 
+    /**
+     * Handles key press events for navigating command history.
+     * @param event The KeyEvent to handle.
+     */
+    private void handleKeyPressed(KeyEvent event) {
+        if (event.getCode() == KeyCode.UP) {
+            String previousCommand = commandHistory.getPreviousCommand();
+            if (previousCommand != null) {
+                commandTextField.setText(previousCommand);
+                commandTextField.positionCaret(commandTextField.getText().length());
+            }
+            event.consume();
+        } else if (event.getCode() == KeyCode.DOWN) {
+            String nextCommand = commandHistory.getNextCommand();
+            if (nextCommand != null) {
+                commandTextField.setText(nextCommand);
+                commandTextField.positionCaret(commandTextField.getText().length());
+            } else {
+                commandTextField.clear();
+            }
+            event.consume();
+        }
+    }
+
     /**
      * Sets the command box style to use the default style.
      */

src/main/java/seedu/address/ui/util/CommandHistory.java

@@ -0,0 +1,60 @@
+package seedu.address.ui.util;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Manages the history of commands entered by the user.
+ */
+public class CommandHistory {
+    private final List<String> commandHistory;
+    private int historyIndex;
+
+    /**
+     * Constructs a {@code CommandHistory} object.
+     */
+    public CommandHistory() {
+        commandHistory = new ArrayList<>();
+        historyIndex = -1; // Start with no commands
+    }
+
+    /**
+     * Adds a command to the history.
+     * Resets the index to point to the latest command.
+     *
+     * @param command The command to be added to the history.
+     */
+    public void addCommand(String command) {
+        commandHistory.add(command);
+        historyIndex = commandHistory.size(); // Reset to end of list
+    }
+
+    /**
+     * Returns the previous command in history.
+     * If at the start, it returns null.
+     *
+     * @return The previous command, or null if at the start of the list.
+     */
+    public String getPreviousCommand() {
+        if (historyIndex > 0) {
+            historyIndex--;
+            return commandHistory.get(historyIndex);
+        }
+        return null; // No previous command
+    }
+
+    /**
+     * Returns the next command in history.
+     * If at the end, it returns null.
+     *
+     * @return The next command, or null if at the end of the list.
+     */
+    public String getNextCommand() {
+        if (historyIndex < commandHistory.size() - 1) {
+            historyIndex++;
+            return commandHistory.get(historyIndex);
+        }
+        historyIndex = commandHistory.size(); // Reset to end
+        return null; // No next command
+    }
+}

src/test/java/seedu/address/ui/CommandHistoryTest.java

@@ -0,0 +1,105 @@
+package seedu.address.ui;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import seedu.address.ui.util.CommandHistory;
+
+/**
+ * Unit tests for {@code CommandHistory}.
+ */
+public class CommandHistoryTest {
+
+    private CommandHistory commandHistory;
+
+    @BeforeEach
+    public void setUp() {
+        commandHistory = new CommandHistory();
+    }
+
+    @Test
+    public void addCommand_singleCommand_success() {
+        commandHistory.addCommand("first command");
+        assertEquals("first command", commandHistory.getPreviousCommand());
+    }
+
+    @Test
+    public void addCommand_multipleCommands_success() {
+        commandHistory.addCommand("first command");
+        commandHistory.addCommand("second command");
+        commandHistory.addCommand("third command");
+
+        assertEquals("third command", commandHistory.getPreviousCommand());
+        assertEquals("second command", commandHistory.getPreviousCommand());
+        assertEquals("first command", commandHistory.getPreviousCommand());
+    }
+
+    @Test
+    public void getPreviousCommand_noHistory_returnsNull() {
+        assertNull(commandHistory.getPreviousCommand());
+    }
+
+    @Test
+    public void getPreviousCommand_atStartOfHistory_returnsNull() {
+        commandHistory.addCommand("first command");
+
+        // Move to the start of the history
+        commandHistory.getPreviousCommand();
+        assertNull(commandHistory.getPreviousCommand());
+    }
+
+    @Test
+    public void getNextCommand_noHistory_returnsNull() {
+        assertNull(commandHistory.getNextCommand());
+    }
+
+    @Test
+    public void getNextCommand_atEndOfHistory_returnsNull() {
+        commandHistory.addCommand("first command");
+        commandHistory.addCommand("second command");
+
+        // Move to the start of history
+        commandHistory.getPreviousCommand();
+        commandHistory.getPreviousCommand();
+
+        // Move forward to the end of history
+        commandHistory.getNextCommand();
+        commandHistory.getNextCommand();
+        assertNull(commandHistory.getNextCommand());
+    }
+
+    @Test
+    public void getNextCommand_fromMiddleOfHistory_success() {
+        commandHistory.addCommand("first command");
+        commandHistory.addCommand("second command");
+        commandHistory.addCommand("third command");
+
+        // Move to the start of history
+        commandHistory.getPreviousCommand();
+        commandHistory.getPreviousCommand();
+        commandHistory.getPreviousCommand();
+
+        // Move forward one step in history
+        assertEquals("second command", commandHistory.getNextCommand());
+    }
+
+    @Test
+    public void addCommand_afterNavigatingHistory_resetsHistoryIndex() {
+        commandHistory.addCommand("first command");
+        commandHistory.addCommand("second command");
+
+        // Move to the start of history
+        commandHistory.getPreviousCommand();
+        commandHistory.getPreviousCommand();
+
+        // Add a new command
+        commandHistory.addCommand("new command");
+
+        // New command should be at the end of history
+        assertEquals("new command", commandHistory.getPreviousCommand());
+        assertNull(commandHistory.getNextCommand()); // At the end of history
+    }
+}