Improved error message

frontend/styles/view/error-notification.css

@@ -1,3 +1,12 @@
 #errorNotificationContent {
 	align-items: center;
-}
+}
+
+#additionalInfo {
+	padding: 0;
+	margin: 0;
+}
+
+#errorSummary {
+	color: white;
+}

frontend/styles/view/main/error-details.css

@@ -0,0 +1,3 @@
+[part="toggle"] {
+	color: white;
+}

src/main/java/edu/kit/typicalc/view/main/ErrorNotification.java

@@ -2,37 +2,60 @@ package edu.kit.typicalc.view.main;
 
 import com.vaadin.flow.component.button.Button;
 import com.vaadin.flow.component.dependency.CssImport;
+import com.vaadin.flow.component.details.Details;
+import com.vaadin.flow.component.html.Paragraph;
 import com.vaadin.flow.component.html.Span;
 import com.vaadin.flow.component.notification.Notification;
 import com.vaadin.flow.component.notification.NotificationVariant;
 import com.vaadin.flow.component.orderedlayout.VerticalLayout;
 
+import edu.kit.typicalc.model.parser.ParseError;
+
 /**
  * The notification being displayed on invalid input.
  */
 @CssImport("./styles/view/error-notification.css")
+@CssImport(value = "./styles/view/main/error-details.css", themeFor = "vaadin-details")
 public class ErrorNotification extends Notification {
 
     private static final long serialVersionUID = 239587L;
 
     private static final String NOTIFICATION_ID = "errorNotification";
     private static final String NOTIFICATION_CONTENT_ID = "errorNotificationContent";
+    private static final String ADDITIONAL_INFO_ID = "additionalInfo";
+    private static final String ERROR_SUMMARY_ID = "errorSummary";
 
     /**
-     * Creates a new ErrorNotification with a specific error message.
+     * Creates a new ErrorNotification with a specific error.
      *
-     * @param errorMessage the error message
+     * @param error the error
      */
-    protected ErrorNotification(String errorMessage) {
+    protected ErrorNotification(ParseError error) {
         VerticalLayout container = new VerticalLayout();
         container.setId(NOTIFICATION_CONTENT_ID);
-        Span errorSpan = new Span(errorMessage);
         Button closeButton = new Button(getTranslation("root.close"), event -> this.close());
 
-        container.add(errorSpan, closeButton);
+        container.add(buildErrorMessage(error), closeButton);
         addThemeVariants(NotificationVariant.LUMO_ERROR);
         add(container);
         setPosition(Position.MIDDLE);
         setId(NOTIFICATION_ID);
     }
+    
+    private Details buildErrorMessage(ParseError error) {
+        VerticalLayout additionalInformation = new VerticalLayout();
+        additionalInformation.setId(ADDITIONAL_INFO_ID);
+        Paragraph summary = new Paragraph(getTranslation("root." + error.toString()));
+        summary.setId(ERROR_SUMMARY_ID);
+        Details generalInformation = new Details(summary, additionalInformation);
+        
+        if (error == ParseError.TOO_FEW_TOKENS) {
+            additionalInformation.add(new Span(getTranslation("root.tooFewTokensHelp")));
+        } else {
+            additionalInformation.add(new Span(getTranslation("root.wrongCharacter") + error.getCause().getText()));
+            additionalInformation.add(new Span(getTranslation("root.position") + error.getCause().getPos()));
+        }
+        
+        return generalInformation;
+    }
 }

src/main/java/edu/kit/typicalc/view/main/InputBar.java

@@ -9,7 +9,6 @@ import com.vaadin.flow.component.dependency.JsModule;
 import com.vaadin.flow.component.dialog.Dialog;
 import com.vaadin.flow.component.icon.Icon;
 import com.vaadin.flow.component.icon.VaadinIcon;
-import com.vaadin.flow.component.notification.Notification;
 import com.vaadin.flow.component.orderedlayout.HorizontalLayout;
 import com.vaadin.flow.component.textfield.TextField;
 import com.vaadin.flow.i18n.LocaleChangeEvent;
@@ -58,7 +57,6 @@ public class InputBar extends HorizontalLayout implements LocaleChangeObserver {
         inputField.setId(INPUT_FIELD_ID);
         inputField.setClearButtonVisible(true);
         inputField.setMaxLength(MAX_INPUT_LENGTH);
-        // TODO: perhaps remove the error message? more than 1000 can't be entered now
         // attach a listener that replaces \ with λ
         // JavaScript is used because Vaadin does not have APIs for selectionStart/selectionEnd
         // and this will be much faster than a bunch of network round trips per character entered!
@@ -110,13 +108,8 @@ public class InputBar extends HorizontalLayout implements LocaleChangeObserver {
     private void onTypeInferButtonClick(Consumer<Pair<String, Map<String, String>>> callback) {
         String currentInput = inputField.getOptionalValue().orElse(StringUtils.EMPTY);
 
-        if (currentInput.length() <= MAX_INPUT_LENGTH) {
-            UI.getCurrent().getPage().setTitle(getTranslation("root.typicalc") + " - " + currentInput);
-            callback.accept(Pair.of(currentInput, typeAssumptionsArea.getTypeAssumptions()));
-        } else {
-            Notification errorNotification = new ErrorNotification(getTranslation("root.overlongInput"));
-            errorNotification.open();
-        }
+        UI.getCurrent().getPage().setTitle(getTranslation("root.typicalc") + " - " + currentInput);
+        callback.accept(Pair.of(currentInput, typeAssumptionsArea.getTypeAssumptions()));
     }
 
     private void onTypeAssumptionsButton() {

src/main/java/edu/kit/typicalc/view/main/MainViewImpl.java

@@ -60,8 +60,7 @@ public class MainViewImpl extends AppLayout
 
     @Override
     public void displayError(ParseError error) {
-        //TODO add error keys to bundle
-        Notification errorNotification = new ErrorNotification(getTranslation("root." + error.toString()));
+        Notification errorNotification = new ErrorNotification(error);
         errorNotification.open();
     }
 

src/main/resources/language/translation_de.properties

@@ -63,6 +63,12 @@ root.helpShareButton=Durch Klicken des Teilen Knopfs öffnet sich ein Dialog, in
 Typherleitungsbaums des eingegebenen Terms und die benötigen Pakete zum Einbinden des LaTeX-Codes angezeigt werden. \
 Zusätzlich dazu enthält der Dialog einen Permalink zur aktuellen Seite, der sowohl den Term als auch die Typannahmen \
 kodiert.
+root.TOO_FEW_TOKENS=Falsche Eingabe! Der Term endet abrupt.
+root.tooFewTokensHelp=Überprüfen sie, ob alle Let-, Abs- und App-Terme über die nötigen Argumente verfügen.
+root.UNEXPECTED_TOKEN=Der Term entspricht nicht der im Info-Dialog spezifizierten Syntax!
+root.UNEXPECTED_CHARACTER=Der Term enhält ein Zeichen, welches an dieser Stelle nicht erlaubt ist!
+root.wrongCharacter=Falsches Zeichen: \u0020
+root.position=An Position: \u0020 
 
 root.absLetLatex=\
 \\begin{prooftree}\