Gets previous input

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

@@ -1,8 +1,12 @@
 package seedu.address.ui;
 
+import java.util.ArrayList;
+
 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;
@@ -17,6 +21,7 @@ public class CommandBox extends UiPart<Region> {
     private static final String FXML = "CommandBox.fxml";
 
     private final CommandExecutor commandExecutor;
+    private final InputHistory inputs;
 
     @FXML
     private TextField commandTextField;
@@ -27,6 +32,7 @@ public class CommandBox extends UiPart<Region> {
     public CommandBox(CommandExecutor commandExecutor) {
         super(FXML);
         this.commandExecutor = commandExecutor;
+        this.inputs = new InputHistory();
         // calls #setStyleToDefault() whenever there is a change to the text of the command box.
         commandTextField.textProperty().addListener((unused1, unused2, unused3) -> setStyleToDefault());
     }
@@ -42,13 +48,53 @@ private void handleCommandEntered() {
         }
 
         try {
+            inputs.add(commandText);
             commandExecutor.execute(commandText);
             commandTextField.setText("");
         } catch (CommandException | ParseException e) {
             setStyleToIndicateCommandFailure();
         }
     }
 
+    /**
+     * Handles UP and DOWN key pressed event.
+     */
+    @FXML
+    private void handleClick(KeyEvent keyEvent) {
+        KeyCode clickedKey = keyEvent.getCode();
+
+        if (clickedKey.equals(KeyCode.UP)) {
+            keyEvent.consume();
+            getPreviousInput();
+        } else if (clickedKey.equals(KeyCode.DOWN)) {
+            keyEvent.consume();
+            getNextInput();
+        }
+    }
+
+    private void getPreviousInput() {
+        if (inputs.hasPreviousInput()) {
+            updateText(inputs.getPreviousInput());
+        }
+    }
+
+    private void getNextInput() {
+        if (inputs.hasNextInput()) {
+            updateText(inputs.getNextInput());
+        } else {
+            updateText("");
+            inputs.setLastIndex();
+        }
+    }
+
+    /**
+     * Change current text with the given input.
+     */
+    private void updateText(String input) {
+        commandTextField.setText(input);
+        commandTextField.positionCaret(input.length());
+    }
+
     /**
      * Sets the command box style to use the default style.
      */
@@ -82,4 +128,71 @@ public interface CommandExecutor {
         CommandResult execute(String commandText) throws CommandException, ParseException;
     }
 
+    /**
+     * Represents the history of inputs given by the user.
+     */
+    public class InputHistory extends ArrayList<String> {
+        private int index;
+
+        /**
+         * Constructs the InputHistory.
+         */
+        public InputHistory() {
+            super();
+            super.add("");
+            index = 1;
+        }
+
+        @Override
+        public boolean add(String input) {
+            if (!input.equals(super.get(super.size() - 1))) {
+                super.add(input);
+            }
+            index = super.size();
+            return true;
+        }
+
+        /**
+         * Sets the index to be equal to the list size.
+         */
+        public void setLastIndex() {
+            index = super.size();
+        }
+
+        /**
+         * Checks whether the list has previous input.
+         * @return boolean
+         */
+        public boolean hasPreviousInput() {
+            return index > 0;
+        }
+
+        /**
+         * Checks whether the list has next input.
+         * @return boolean
+         */
+        public boolean hasNextInput() {
+            return index < super.size() - 1;
+        }
+
+        /**
+         * Gets the previous input
+         * @return the previous input
+         */
+        public String getPreviousInput() {
+            assert index > 0;
+            index--;
+            return super.get(index);
+        }
+
+        /**
+         * Gets the next input
+         * @return the next input
+         */
+        public String getNextInput() {
+            assert index < super.size() - 1;
+            index++;
+            return super.get(index);
+        }
+    }
 }

src/main/resources/view/CommandBox.fxml

@@ -4,6 +4,6 @@
 <?import javafx.scene.layout.StackPane?>
 
 <StackPane styleClass="stack-pane" xmlns="http://javafx.com/javafx/17" xmlns:fx="http://javafx.com/fxml/1">
-  <TextField fx:id="commandTextField" onAction="#handleCommandEntered" promptText="Enter command here..."/>
+  <TextField fx:id="commandTextField" onAction="#handleCommandEntered" onKeyPressed="#handleClick" promptText="Enter command here..."/>
 </StackPane>