Better unicode handling

- Pass raw input into KeyEvent if it comes as unicode from jline
- Fixes in InputView to handle wide chars and cursor position
- Fixes #845

spring-shell-core/src/main/java/org/springframework/shell/component/view/TerminalUI.java

@@ -40,8 +40,8 @@ import org.springframework.shell.component.view.event.EventLoop;
 import org.springframework.shell.component.view.event.KeyBinder;
 import org.springframework.shell.component.view.event.KeyEvent;
 import org.springframework.shell.component.view.event.KeyHandler;
-import org.springframework.shell.component.view.event.MouseEvent;
 import org.springframework.shell.component.view.event.KeyHandler.KeyHandlerResult;
+import org.springframework.shell.component.view.event.MouseEvent;
 import org.springframework.shell.component.view.event.MouseHandler;
 import org.springframework.shell.component.view.event.MouseHandler.MouseHandlerResult;
 import org.springframework.shell.component.view.geom.Rectangle;
@@ -333,7 +333,7 @@ public class TerminalUI {
 		else if (operation == KeyEvent.Key.Unicode) {
 			String lastBinding = bindingReader.getLastBinding();
 			if (StringUtils.hasLength(lastBinding)) {
-				dispatchKeyEvent(KeyEvent.of(lastBinding.charAt(0)));
+				dispatchKeyEvent(KeyEvent.of(lastBinding));
 			}
 		}
 		else if (operation == KeyEvent.Key.Mouse) {

spring-shell-core/src/main/java/org/springframework/shell/component/view/control/InputView.java

@@ -15,6 +15,9 @@
  */
 package org.springframework.shell.component.view.control;
 
+import java.util.ArrayList;
+import java.util.stream.Collectors;
+
 import org.springframework.shell.component.view.event.KeyEvent;
 import org.springframework.shell.component.view.event.KeyEvent.Key;
 import org.springframework.shell.component.view.event.KeyHandler;
@@ -29,8 +32,8 @@ import org.springframework.shell.component.view.screen.Screen;
  */
 public class InputView extends BoxView {
 
-	private final StringBuilder text = new StringBuilder();
-	private int cursorPosition = 0;
+	private final ArrayList<String> text = new ArrayList<>();
+	private int cursorIndex = 0;
 
 	@Override
 	protected void initInternal() {
@@ -50,6 +53,9 @@ public class InputView extends BoxView {
 				int plainKey = event.getPlainKey();
 				add(new String(new char[]{(char)plainKey}));
 			}
+			else if (event.isKey(KeyEvent.Key.Unicode)) {
+				add(event.data());
+			}
 			return KeyHandler.resultOf(event, consumed, null);
 		};
 		return handler.thenIfNotConsumed(super.getKeyHandler());
@@ -58,46 +64,51 @@ public class InputView extends BoxView {
 	@Override
 	protected void drawInternal(Screen screen) {
 		Rectangle rect = getInnerRect();
-		String s = text.toString();
+		String s = getInputText();
 		screen.writerBuilder().build().text(s, rect.x(), rect.y());
 		screen.setShowCursor(hasFocus());
-		screen.setCursorPosition(new Position(rect.x() + cursorPosition, rect.y()));
+		int sum = text.stream().limit(cursorIndex).mapToInt(text -> text.length()).sum();
+		screen.setCursorPosition(new Position(rect.x() + sum, rect.y()));
 		super.drawInternal(screen);
 	}
 
+	/**
+	 * Get a current known input text.
+	 *
+	 * @return current input text
+	 */
 	public String getInputText() {
-		return text.toString();
+		return text.stream().collect(Collectors.joining());
 	}
 
-	// private void enter(KeyEvent event) {
-	// 	// getShellMessageListener().onMessage(ShellMessageBuilder.ofViewFocus("enter", this));
-	// }
-
-	// private void leave(KeyEvent event) {
-	// 	// getShellMessageListener().onMessage(ShellMessageBuilder.ofViewFocus("leave", this));
-	// }
-
 	private void add(String data) {
-		text.append(data);
-		right();
+		text.add(data);
+		moveCursor(1);
 	}
 
 	private void backspace() {
-		if (cursorPosition > 0) {
-			text.deleteCharAt(cursorPosition - 1);
+		if (cursorIndex > 0) {
+			text.remove(cursorIndex - 1);
 		}
 		left();
 	}
 
 	private void delete() {
-		text.deleteCharAt(cursorPosition);
+		text.remove(cursorIndex);
+	}
+
+	private void moveCursor(int index) {
+		int toIndex = cursorIndex + index;
+		if (toIndex > -1 && toIndex <= text.size()) {
+			cursorIndex = toIndex;
+		}
 	}
 
 	private void left() {
-		cursorPosition--;
+		moveCursor(-1);
 	}
 
 	private void right() {
-		cursorPosition++;
+		moveCursor(1);
 	}
 }

spring-shell-core/src/main/java/org/springframework/shell/component/view/event/KeyEvent.java

@@ -23,12 +23,15 @@ package org.springframework.shell.component.view.event;
  *
  *
  */
-public record KeyEvent(int key) {
+public record KeyEvent(int key, String data) {
 
 	public static KeyEvent of(int key) {
-		return new KeyEvent(key);
+		return new KeyEvent(key, null);
 	}
 
+	public static KeyEvent of(String raw) {
+		return new KeyEvent(Key.Unicode, raw);
+	}
 
 	public boolean hasCtrl() {
 		return ((key >> 30) & 1) == 1;

spring-shell-core/src/test/java/org/springframework/shell/component/view/control/AbstractViewTests.java

@@ -88,6 +88,10 @@ public class AbstractViewTests {
 		return handleKeyEvent(view, KeyEvent.of(key));
 	}
 
+	protected KeyHandlerResult handleKey(View view, String key) {
+		return handleKeyEvent(view, KeyEvent.of(key));
+	}
+
 	protected KeyHandlerResult handleKeyEvent(View view, KeyEvent key) {
 		return view.getKeyHandler().handle(KeyHandler.argsOf(key));
 	}

spring-shell-core/src/test/java/org/springframework/shell/component/view/control/InputViewTests.java

@@ -15,37 +15,138 @@
  */
 package org.springframework.shell.component.view.control;
 
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Nested;
 import org.junit.jupiter.api.Test;
 
 import org.springframework.shell.component.view.event.KeyEvent;
+import org.springframework.shell.component.view.event.KeyEvent.Key;
+import org.springframework.test.util.ReflectionTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
 class InputViewTests extends AbstractViewTests {
 
-	@Test
-	void shouldShowInput() {
-		InputView view = new InputView();
-		view.setShowBorder(true);
-		view.setRect(0, 0, 80, 24);
+	private static final String CURSOR_INDEX_FIELD = "cursorIndex";
 
-		dispatchEvent(view, KeyEvent.of('1'));
-		view.draw(screen24x80);
+	@Nested
+	class Input {
+
+		InputView view;
+
+		@BeforeEach
+		void setup() {
+			view = new InputView();
+			configure(view);
+		}
+
+		@Test
+		void shouldShowPlainText() {
+			view.setShowBorder(true);
+			view.setRect(0, 0, 80, 24);
+
+			dispatchEvent(view, KeyEvent.of('1'));
+			view.draw(screen24x80);
+
+			assertThat(forScreen(screen24x80)).hasHorizontalText("1", 1, 1, 1);
+			assertThat(forScreen(screen24x80)).hasCursorInPosition(2, 1);
+		}
+
+		@Test
+		void shouldShowUnicode() {
+			view.setShowBorder(true);
+			view.setRect(0, 0, 80, 24);
+
+			dispatchEvent(view, KeyEvent.of('★'));
+			view.draw(screen24x80);
+
+			assertThat(forScreen(screen24x80)).hasHorizontalText("★", 1, 1, 1);
+			assertThat(forScreen(screen24x80)).hasCursorInPosition(2, 1);
+		}
+
+		@Test
+		void shouldShowUnicodeEmoji() {
+			view.setShowBorder(true);
+			view.setRect(0, 0, 80, 24);
+
+			dispatchEvent(view, KeyEvent.of("😂"));
+			view.draw(screen24x80);
+
+			assertThat(forScreen(screen24x80)).hasHorizontalText("😂", 1, 1, 2);
+			assertThat(forScreen(screen24x80)).hasCursorInPosition(3, 1);
+		}
 
-		assertThat(forScreen(screen24x80)).hasHorizontalText("1", 1, 1, 1);
-		assertThat(forScreen(screen24x80)).hasCursorInPosition(2, 1);
 	}
 
-	@Test
-	void shouldShowUnicode() {
-		InputView view = new InputView();
-		view.setShowBorder(true);
-		view.setRect(0, 0, 80, 24);
+	@Nested
+	class CursorPositions {
 
-		dispatchEvent(view, KeyEvent.of('★'));
-		view.draw(screen24x80);
+		InputView view;
+
+		@BeforeEach
+		void setup() {
+			view = new InputView();
+			configure(view);
+		}
+
+		int cursorIndex() {
+			return (Integer) ReflectionTestUtils.getField(view, CURSOR_INDEX_FIELD);
+		}
+
+		@Test
+		void initialCursorPosition() {
+			assertThat(cursorIndex()).isEqualTo(0);
+		}
+
+		@Test
+		void shouldNotMoveOutOfBoundsIfMovingRight() {
+			handleKey(view, Key.CursorRight);
+			assertThat(cursorIndex()).isEqualTo(0);
+		}
+
+		@Test
+		void shouldNotMoveOutOfBoundsIfMovingLeft() {
+			handleKey(view, Key.CursorLeft);
+			assertThat(cursorIndex()).isEqualTo(0);
+		}
+
+		@Test
+		void shouldMoveWithInputKeysNarrow() {
+			handleKey(view, Key.a);
+			assertThat(cursorIndex()).isEqualTo(1);
+		}
+
+		@Test
+		void shouldMoveWithInputKeysWide() {
+			handleKey(view, "😂");
+			assertThat(cursorIndex()).isEqualTo(1);
+		}
 
-		assertThat(forScreen(screen24x80)).hasHorizontalText("★", 1, 1, 1);
-		assertThat(forScreen(screen24x80)).hasCursorInPosition(2, 1);
 	}
+
+	@Nested
+	class MoveAndDeletions {
+
+		InputView view;
+
+		@BeforeEach
+		void setup() {
+			view = new InputView();
+			configure(view);
+		}
+
+		int cursorIndex() {
+			return (Integer) ReflectionTestUtils.getField(view, CURSOR_INDEX_FIELD);
+		}
+
+		@Test
+		void addEmojiAndBackspace() {
+			handleKey(view, "😂");
+			assertThat(cursorIndex()).isEqualTo(1);
+			handleKey(view, Key.Backspace);
+			assertThat(cursorIndex()).isEqualTo(0);
+		}
+
+	}
+
 }