Allow use of tab in editor panel, fix tab skipping tokens (#578)

* Gracefully fall back when lang/index.txt is absent

* Allow use of tab in editor panel, fix tab skipping tokens

* Document #navigateToNextObfuscatedToken async requirements

Author: Geolykt

enigma-swing/src/main/java/cuchaz/enigma/gui/panels/EditorPanel.java

@@ -1,11 +1,13 @@
 package cuchaz.enigma.gui.panels;
 
+import java.awt.AWTKeyStroke;
 import java.awt.Color;
 import java.awt.Component;
 import java.awt.Font;
 import java.awt.GridBagConstraints;
 import java.awt.GridBagLayout;
 import java.awt.GridLayout;
+import java.awt.KeyboardFocusManager;
 import java.awt.Rectangle;
 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
@@ -16,8 +18,11 @@
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Comparator;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.NavigableSet;
+import java.util.Set;
 
 import javax.swing.JButton;
 import javax.swing.JComponent;
@@ -120,6 +125,11 @@ public EditorPanel(Gui gui) {
 		customizeEditor(this.editor);
 		this.editor.addCaretListener(event -> onCaretMove(event.getDot(), this.mouseIsPressed));
 
+		// Remove the tab key from focus traversal keys (we give it a different meaning)
+		Set<AWTKeyStroke> focusTraversalKeys = new HashSet<>(this.editor.getFocusTraversalKeys(KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS));
+		focusTraversalKeys.removeIf(key -> key.getKeyCode() == KeyEvent.VK_TAB);
+		this.editor.setFocusTraversalKeys(KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, focusTraversalKeys);
+
 		// set unit increment to height of one line, the amount scrolled per
 		// mouse wheel rotation is then controlled by OS settings
 		this.editorScrollPane.getVerticalScrollBar().setUnitIncrement(this.editor.getFontMetrics(this.editor.getFont()).getHeight());
@@ -199,6 +209,9 @@ public void keyPressed(KeyEvent event) {
 						EditorPanel.this.shouldNavigateOnClick = true; // CTRL
 						break;
 					}
+				} else if (event.getKeyCode() == KeyEvent.VK_TAB) {
+					EditorPanel.this.navigateToNextObfuscatedToken();
+					event.consume();
 				}
 			}
 
@@ -668,6 +681,36 @@ private void showReference0(EntryReference<Entry<?>, Entry<?>> reference) {
 		}
 	}
 
+	/**
+	 * Navigate to the next obfuscated token that can be renamed.
+	 *
+	 * <p>If the tokens are damaged, then this method should not be called
+	 * synchronously. Instead, the call should be wrapped in a
+	 * {@link SwingUtilities#invokeLater(Runnable)}. Failing to do so
+	 * will induce invalid token highlighting regions.
+	 */
+	public void navigateToNextObfuscatedToken() {
+		int caretPos = this.getEditor().getCaretPosition();
+		Token token = this.getToken(this.getEditor().getCaretPosition());
+		NavigableSet<Token> obfuscatedTokens = this.getSource().getTokenStore().getByType().get(RenamableTokenType.OBFUSCATED);
+		Token next;
+
+		if (token == null) {
+			next = obfuscatedTokens.higher(new Token(caretPos, caretPos, null));
+		} else {
+			next = obfuscatedTokens.higher(token);
+		}
+
+		if (next == null) {
+			// Wrap to start of document
+			next = obfuscatedTokens.pollFirst();
+		}
+
+		if (next != null) {
+			this.navigateToToken(next);
+		}
+	}
+
 	public void navigateToToken(Token token) {
 		if (token == null) {
 			throw new IllegalArgumentException("Token cannot be null!");

enigma-swing/src/main/java/cuchaz/enigma/gui/panels/IdentifierPanel.java

@@ -23,8 +23,6 @@
 import cuchaz.enigma.gui.util.GridBagConstraintsBuilder;
 import cuchaz.enigma.gui.util.GuiUtil;
 import cuchaz.enigma.gui.util.ScaleUtil;
-import cuchaz.enigma.source.RenamableTokenType;
-import cuchaz.enigma.source.Token;
 import cuchaz.enigma.translation.mapping.AccessModifier;
 import cuchaz.enigma.translation.mapping.EntryChange;
 import cuchaz.enigma.translation.mapping.EntryMapping;
@@ -197,36 +195,19 @@ public boolean tryStopEditing(ConvertingTextField field, StopEditingCause cause)
 
 				@Override
 				public void onStopEditing(ConvertingTextField field, StopEditingCause cause) {
+					EditorPanel e = gui.getActiveEditor();
+
 					if (cause != StopEditingCause.ABORT) {
 						vc.reset();
 						vc.setActiveElement(field);
 						doRename(field.getText());
 
-						if (cause == StopEditingCause.TAB) {
-							EditorPanel editor = gui.getActiveEditor();
-
-							if (editor == null) {
-								return;
-							}
-
-							Token token = editor.getToken(editor.getEditor().getCaretPosition());
-
-							SwingUtilities.invokeLater(() -> {
-								Token next = editor.getSource().getTokenStore().getByType().get(RenamableTokenType.OBFUSCATED).higher(token);
-
-								if (next == null) {
-									editor.getEditor().requestFocusInWindow();
-								} else {
-									editor.navigateToToken(next);
-								}
-							});
-
-							return;
+						if (cause == StopEditingCause.TAB && e != null) {
+							// invokeLater as per the method's javadocs
+							SwingUtilities.invokeLater(e::navigateToNextObfuscatedToken);
 						}
 					}
 
-					EditorPanel e = gui.getActiveEditor();
-
 					if (e != null) {
 						e.getEditor().requestFocusInWindow();
 					}

enigma/src/main/java/cuchaz/enigma/utils/I18n.java

@@ -101,6 +101,11 @@ public static ArrayList<String> getAvailableLanguages() {
 			List<String> availableTranslations;
 
 			try (InputStream is = cl.getResourceAsStream("lang/index.txt")) {
+				if (is == null) {
+					// This scenario should only really happen when launching from an IDE that does not run the necessary gradle tasks
+					throw new IOException("Resource 'lang/index.txt' not found");
+				}
+
 				availableTranslations = Arrays.asList(
 						new String(is.readAllBytes(), StandardCharsets.UTF_8)
 								.split("\n")