Add Markdown rendering to AI Chat

CHANGELOG.md

@@ -24,6 +24,7 @@ Note that this project **does not** adhere to [Semantic Versioning](https://semv
 - We added an "Open example library" button to Welcome Tab. [#13014](https://github.com/JabRef/jabref/issues/13014)
 - We added automatic detection and selection of the identifier type (e.g., DOI, ISBN, arXiv) based on clipboard content when opening the "New Entry" dialog [#13111](https://github.com/JabRef/jabref/pull/13111)
 - We added support for import of a Refer/BibIX file format. [#13069](https://github.com/JabRef/jabref/issues/13069)
+- We added markdown rendering and copy-paste capabilities to AI chat responses. [#12234](https://github.com/JabRef/jabref/issues/12234)
 
 ### Changed
 

jabgui/src/main/java/module-info.java

@@ -189,5 +189,8 @@
     // requires mslinks;
     requires org.antlr.antlr4.runtime;
     requires org.libreoffice.uno;
+    requires flexmark;
+    requires flexmark.util.data;
+    requires flexmark.util.ast;
     // endregion
 }

jabgui/src/main/java/org/jabref/gui/JabRefGUI.java

@@ -18,6 +18,7 @@
 import org.jabref.gui.help.VersionWorker;
 import org.jabref.gui.icon.IconTheme;
 import org.jabref.gui.keyboard.KeyBindingRepository;
+import org.jabref.gui.keyboard.SelectableTextFlowKeyBindings;
 import org.jabref.gui.keyboard.TextInputKeyBindings;
 import org.jabref.gui.openoffice.OOBibBaseConnect;
 import org.jabref.gui.preferences.GuiPreferences;
@@ -256,10 +257,10 @@ private void openWindow() {
         themeManager.installCss(scene);
 
         LOGGER.debug("Handle TextEditor key bindings");
-        scene.addEventFilter(KeyEvent.KEY_PRESSED, event -> TextInputKeyBindings.call(
-                scene,
-                event,
-                preferences.getKeyBindingRepository()));
+        scene.addEventFilter(KeyEvent.KEY_PRESSED, event -> {
+            TextInputKeyBindings.call(scene, event, preferences.getKeyBindingRepository());
+            SelectableTextFlowKeyBindings.call(scene, event, preferences.getKeyBindingRepository());
+        });
 
         mainStage.setTitle(JabRefFrame.FRAME_TITLE);
         mainStage.getIcons().addAll(IconTheme.getLogoSetFX());

jabgui/src/main/java/org/jabref/gui/ai/components/aichat/chatmessage/ChatMessageComponent.java

@@ -2,19 +2,24 @@
 
 import java.util.function.Consumer;
 
+import javafx.beans.binding.Bindings;
+import javafx.beans.binding.NumberBinding;
 import javafx.beans.property.ObjectProperty;
 import javafx.beans.property.SimpleObjectProperty;
 import javafx.fxml.FXML;
 import javafx.geometry.NodeOrientation;
+import javafx.geometry.Pos;
 import javafx.scene.control.Label;
 import javafx.scene.layout.HBox;
+import javafx.scene.layout.Pane;
+import javafx.scene.layout.Priority;
 import javafx.scene.layout.VBox;
 
+import org.jabref.gui.util.MarkdownTextFlow;
 import org.jabref.logic.ai.util.ErrorMessage;
 import org.jabref.logic.l10n.Localization;
 
 import com.airhacks.afterburner.views.ViewLoader;
-import com.dlsc.gemsfx.ExpandingTextArea;
 import dev.langchain4j.data.message.AiMessage;
 import dev.langchain4j.data.message.ChatMessage;
 import dev.langchain4j.data.message.UserMessage;
@@ -30,15 +35,17 @@ public class ChatMessageComponent extends HBox {
     @FXML private HBox wrapperHBox;
     @FXML private VBox vBox;
     @FXML private Label sourceLabel;
-    @FXML private ExpandingTextArea contentTextArea;
+    @FXML private Pane markdownContentPane;
     @FXML private VBox buttonsVBox;
 
+    private MarkdownTextFlow markdownTextFlow;
+
     public ChatMessageComponent() {
         ViewLoader.view(this)
                   .root(this)
                   .load();
 
-        chatMessage.addListener((observable, oldValue, newValue) -> {
+        chatMessage.addListener((_, _, newValue) -> {
             if (newValue != null) {
                 loadChatMessage();
             }
@@ -68,22 +75,24 @@ private void loadChatMessage() {
             case UserMessage userMessage -> {
                 setColor("-jr-ai-message-user", "-jr-ai-message-user-border");
                 setNodeOrientation(NodeOrientation.RIGHT_TO_LEFT);
+                wrapperHBox.setAlignment(Pos.TOP_RIGHT);
                 sourceLabel.setText(Localization.lang("User"));
-                contentTextArea.setText(userMessage.singleText());
+                markdownTextFlow.setMarkdown(userMessage.singleText());
             }
 
             case AiMessage aiMessage -> {
                 setColor("-jr-ai-message-ai", "-jr-ai-message-ai-border");
                 setNodeOrientation(NodeOrientation.LEFT_TO_RIGHT);
+                wrapperHBox.setAlignment(Pos.TOP_LEFT);
                 sourceLabel.setText(Localization.lang("AI"));
-                contentTextArea.setText(aiMessage.text());
+                markdownTextFlow.setMarkdown(aiMessage.text());
             }
 
             case ErrorMessage errorMessage -> {
                 setColor("-jr-ai-message-error", "-jr-ai-message-error-border");
                 setNodeOrientation(NodeOrientation.LEFT_TO_RIGHT);
                 sourceLabel.setText(Localization.lang("Error"));
-                contentTextArea.setText(errorMessage.getText());
+                markdownTextFlow.setMarkdown(errorMessage.getText());
             }
 
             default ->
@@ -94,6 +103,15 @@ private void loadChatMessage() {
     @FXML
     private void initialize() {
         buttonsVBox.visibleProperty().bind(wrapperHBox.hoverProperty());
+        markdownTextFlow = new MarkdownTextFlow(markdownContentPane);
+        markdownContentPane.getChildren().add(markdownTextFlow);
+        markdownContentPane.minHeightProperty().bind(markdownTextFlow.heightProperty());
+        markdownContentPane.prefHeightProperty().bind(markdownTextFlow.heightProperty());
+        NumberBinding maxUsableWidth = Bindings.createDoubleBinding(() -> getScene() == null ? 600 : getScene().getWidth() - 20, sceneProperty(), getScene() == null ? widthProperty() : getScene().widthProperty());
+        markdownTextFlow.maxWidthProperty().bind(maxUsableWidth);
+        wrapperHBox.maxWidthProperty().bind(maxUsableWidth);
+        setMaxWidth(Double.MAX_VALUE);
+        HBox.setHgrow(this, Priority.ALWAYS);
     }
 
     @FXML

jabgui/src/main/java/org/jabref/gui/keyboard/SelectableTextFlowKeyBindings.java

@@ -0,0 +1,25 @@
+package org.jabref.gui.keyboard;
+
+import javafx.scene.Scene;
+import javafx.scene.input.KeyEvent;
+
+import org.jabref.gui.util.SelectableTextFlow;
+
+public class SelectableTextFlowKeyBindings {
+    public static void call(Scene scene, KeyEvent event, KeyBindingRepository keyBindingRepository) {
+        if (scene.focusOwnerProperty().get() instanceof SelectableTextFlow selectableTextFlow) {
+            keyBindingRepository.mapToKeyBinding(event).ifPresent(binding -> {
+                switch (binding) {
+                    case COPY -> {
+                        selectableTextFlow.copySelectedText();
+                        event.consume();
+                    }
+                    case SELECT_ALL -> {
+                        selectableTextFlow.selectAll();
+                        event.consume();
+                    }
+                }
+            });
+        }
+    }
+}

jabgui/src/main/java/org/jabref/gui/util/MarkdownTextFlow.java

@@ -0,0 +1,176 @@
+package org.jabref.gui.util;
+
+import javafx.geometry.NodeOrientation;
+import javafx.scene.layout.Pane;
+import javafx.scene.text.Text;
+
+import com.vladsch.flexmark.ast.BulletList;
+import com.vladsch.flexmark.ast.BulletListItem;
+import com.vladsch.flexmark.ast.Code;
+import com.vladsch.flexmark.ast.Emphasis;
+import com.vladsch.flexmark.ast.Heading;
+import com.vladsch.flexmark.ast.OrderedList;
+import com.vladsch.flexmark.ast.OrderedListItem;
+import com.vladsch.flexmark.ast.Paragraph;
+import com.vladsch.flexmark.ast.StrongEmphasis;
+import com.vladsch.flexmark.parser.Parser;
+import com.vladsch.flexmark.util.ast.Node;
+import com.vladsch.flexmark.util.ast.NodeVisitor;
+import com.vladsch.flexmark.util.ast.VisitHandler;
+import com.vladsch.flexmark.util.data.MutableDataSet;
+
+/**
+ * A TextFlow that renders Markdown text with support for headings, paragraphs, emphasis, strong emphasis, code blocks, bullet lists, and ordered lists.
+ */
+public class MarkdownTextFlow extends SelectableTextFlow {
+    private final Parser parser;
+    private boolean needsLineBreak = false;
+    private int currentOrderedListIndex = 0;
+
+    /**
+     * Creates a MarkdownTextFlow instance.
+     *
+     * @param parent The parent Pane to which this TextFlow will be added.
+     */
+    public MarkdownTextFlow(Pane parent) {
+        super(parent);
+        this.setNodeOrientation(NodeOrientation.LEFT_TO_RIGHT);
+        this.getStyleClass().add("markdown-textflow");
+
+        MutableDataSet options = new MutableDataSet();
+        this.parser = Parser.builder(options).build();
+    }
+
+    /**
+     * Sets the Markdown text to be rendered in this TextFlow.
+     *
+     * @param markdownText The Markdown text to render. If null or empty, the TextFlow will be cleared.
+     */
+    public void setMarkdown(String markdownText) {
+        this.clear();
+        needsLineBreak = false;
+
+        if (markdownText == null || markdownText.trim().isEmpty()) {
+            return;
+        }
+
+        Node document = parser.parse(markdownText);
+        MarkdownRenderer renderer = new MarkdownRenderer();
+        renderer.visit(document);
+    }
+
+    private void addLineBreak() {
+        if (needsLineBreak && !this.getChildren().isEmpty()) {
+            Text lineBreak = new Text("\n");
+            this.getChildren().add(lineBreak);
+        }
+        needsLineBreak = false;
+    }
+
+    private class MarkdownRenderer {
+        private final NodeVisitor visitor = new NodeVisitor(
+                new VisitHandler<>(Heading.class, this::visit),
+                new VisitHandler<>(Paragraph.class, this::visit),
+                new VisitHandler<>(com.vladsch.flexmark.ast.Text.class, this::visit),
+                new VisitHandler<>(Emphasis.class, this::visit),
+                new VisitHandler<>(StrongEmphasis.class, this::visit),
+                new VisitHandler<>(Code.class, this::visit),
+                new VisitHandler<>(BulletList.class, this::visit),
+                new VisitHandler<>(OrderedList.class, this::visit),
+                new VisitHandler<>(BulletListItem.class, this::visit),
+                new VisitHandler<>(OrderedListItem.class, this::visit)
+        );
+
+        public void visit(Node node) {
+            visitor.visit(node);
+        }
+
+        private void visit(Heading heading) {
+            addLineBreak();
+
+            String content = heading.getText().toString();
+            int level = heading.getLevel();
+
+            Text headingNode = new Text(content);
+            headingNode.getStyleClass().add("markdown-h" + level);
+
+            getChildren().add(headingNode);
+            needsLineBreak = true;
+        }
+
+        private void visit(Paragraph paragraph) {
+            addLineBreak();
+
+            Node parent = paragraph.getParent();
+            boolean isInList = parent instanceof BulletListItem || parent instanceof OrderedListItem;
+
+            if (!isInList && !getChildren().isEmpty()) {
+                addLineBreak();
+            }
+
+            visitor.visitChildren(paragraph);
+            needsLineBreak = true;
+        }
+
+        private void visit(com.vladsch.flexmark.ast.Text text) {
+            String content = text.getChars().toString();
+            Text textNode = new Text(content);
+            getChildren().add(textNode);
+        }
+
+        private void visit(Emphasis emphasis) {
+            String content = emphasis.getText().toString();
+            Text italicText = new Text(content);
+            italicText.getStyleClass().add("markdown-italic");
+            getChildren().add(italicText);
+        }
+
+        private void visit(StrongEmphasis strongEmphasis) {
+            String content = strongEmphasis.getText().toString();
+            Text boldText = new Text(content);
+            boldText.getStyleClass().add("markdown-bold");
+            getChildren().add(boldText);
+        }
+
+        private void visit(Code code) {
+            String content = code.getText().toString();
+            Text codeText = new Text(content);
+            codeText.getStyleClass().add("markdown-code");
+            getChildren().add(codeText);
+        }
+
+        private void visit(BulletList bulletList) {
+            addLineBreak();
+            visitor.visitChildren(bulletList);
+            needsLineBreak = true;
+        }
+
+        private void visit(OrderedList orderedList) {
+            addLineBreak();
+            currentOrderedListIndex = 0;
+            visitor.visitChildren(orderedList);
+            needsLineBreak = true;
+        }
+
+        private void visit(BulletListItem listItem) {
+            addLineBreak();
+
+            Text bulletText = new Text("• ");
+            bulletText.getStyleClass().add("markdown-list-bullet");
+            getChildren().add(bulletText);
+
+            visitor.visitChildren(listItem);
+        }
+
+        private void visit(OrderedListItem listItem) {
+            addLineBreak();
+            currentOrderedListIndex++;
+
+            Text numberText = new Text(currentOrderedListIndex + ". ");
+            numberText.getStyleClass().add("markdown-list-number");
+            getChildren().add(numberText);
+
+            visitor.visitChildren(listItem);
+        }
+    }
+}