Erweiterungen

MQTT_README.md

@@ -133,11 +133,34 @@ Payload:
 - User notifications: v1/users/<username>/notifications
 Payload example:
 {
-  "type": "broadcast|notification",
+ "type": "broadcast|notification",
   "message": "...",
   "timestamp": "2025-09-13T22:10:00"
 }
 
+## Chat Messaging (App ↔ Server)
+
+Mobile apps exchange chat messages with the backend through dedicated topics. JSON samples can be
+found under `src/main/resources/mqtt/chat`.
+
+### App → Server
+- **Topic:** `/server/{clientId}/message`
+- **Payload example:** `src/main/resources/mqtt/chat/incoming-chat-message.json`
+- **Required fields:** `sender`, `receiver`, `content`
+- **Optional fields:** `jobId` (Mongo ObjectId), `jobNumber`
+- Payloads missing required fields or containing invalid `jobId` values are rejected with a warning log.
+
+### Server → App
+- **Topic:** `/client/{receiver}/message`
+- **Payload example:** `src/main/resources/mqtt/chat/outgoing-chat-message.json`
+- **Notes:** `direction` (INCOMING/OUTGOING) and `messageType` (GENERAL/JOB_RELATED) mirror the
+  persisted message entity. `read` remains `false` until the receiver acknowledges the message via the
+  REST API.
+
+### Quality of Service
+- Chat topics inherit the global default QoS 2 (`app.mqtt.default-qos`).
+- Messages are not retained; offline clients rely on QoS queueing on the broker.
+
 Quality of Service & Retain
 - QoS 2 (exactly once) is used by default server side for both inbound subscriptions and outbound publications.
 - Retained messages are disabled by default to avoid stale updates.

src/main/java/de/assecutor/votianlt/controller/MessageController.java

@@ -2,6 +2,7 @@ package de.assecutor.votianlt.controller;
 
 import de.assecutor.votianlt.dto.AppLoginRequest;
 import de.assecutor.votianlt.dto.AppLoginResponse;
+import de.assecutor.votianlt.dto.ChatMessageInboundPayload;
 import de.assecutor.votianlt.dto.JobWithRelatedDataDTO;
 import de.assecutor.votianlt.model.AppUser;
 import de.assecutor.votianlt.model.CargoItem;
@@ -609,43 +610,12 @@ public class MessageController {
         log.info("MQTT Endpoint '/server/{clientId}/message' called with data: {}", payload);
 
         try {
-            // Extract required fields
+            ChatMessageInboundPayload inboundPayload = ChatMessageInboundPayload.fromPayload(payload);
-            String sender = payload.get("sender") != null ? payload.get("sender").toString() : null;
+            messageService.receiveMessageFromClient(inboundPayload);
-            String receiver = payload.get("receiver") != null ? payload.get("receiver").toString() : null;
+            log.info("Successfully saved incoming message from {} to {}", inboundPayload.sender(),
-            String content = payload.get("content") != null ? payload.get("content").toString() : null;
+                    inboundPayload.receiver());
-
+        } catch (IllegalArgumentException validationError) {
-            // Validate required fields
+            log.warn("Incoming chat message rejected: {}", validationError.getMessage());
-            if (sender == null || sender.isBlank() || 
-                receiver == null || receiver.isBlank() || 
-                content == null || content.isBlank()) {
-                log.warn("Incoming message missing required fields: sender={}, receiver={}, content={}", 
-                         sender, receiver, content != null ? "present" : "null");
-                return;
-            }
-
-            // Extract optional job-related fields
-            ObjectId jobId = null;
-            String jobNumber = null;
-            
-            if (payload.get("jobId") != null) {
-                try {
-                    String jobIdStr = payload.get("jobId").toString();
-                    if (!jobIdStr.isBlank()) {
-                        jobId = new ObjectId(jobIdStr);
-                    }
-                } catch (IllegalArgumentException e) {
-                    log.warn("Invalid jobId format in message: {}", payload.get("jobId"));
-                }
-            }
-            
-            if (payload.get("jobNumber") != null) {
-                jobNumber = payload.get("jobNumber").toString();
-            }
-
-            // Save the message using MessageService
-            messageService.receiveMessageFromClient(content, sender, receiver, jobId, jobNumber);
-            log.info("Successfully saved incoming message from {} to {}", sender, receiver);
-
         } catch (Exception e) {
             log.error("Error handling incoming message: {}", e.getMessage(), e);
         }

src/main/java/de/assecutor/votianlt/dto/ChatMessageInboundPayload.java

@@ -0,0 +1,59 @@
+package de.assecutor.votianlt.dto;
+
+import java.util.Map;
+
+import org.bson.types.ObjectId;
+
+/**
+ * Normalized payload for chat messages sent by mobile clients via MQTT.
+ */
+public record ChatMessageInboundPayload(String sender, String receiver, String content, ObjectId jobId, String jobNumber) {
+
+    public static ChatMessageInboundPayload fromPayload(Map<String, Object> payload) {
+        if (payload == null) {
+            throw new IllegalArgumentException("payload must not be null");
+        }
+
+        String sender = extractRequiredString(payload, "sender");
+        String receiver = extractRequiredString(payload, "receiver");
+        String content = extractRequiredString(payload, "content");
+        ObjectId jobId = extractObjectId(payload.get("jobId"), "jobId");
+        String jobNumber = extractOptionalString(payload.get("jobNumber"));
+
+        return new ChatMessageInboundPayload(sender, receiver, content, jobId, jobNumber);
+    }
+
+    public boolean hasJobContext() {
+        return jobId != null;
+    }
+
+    private static String extractRequiredString(Map<String, Object> payload, String key) {
+        Object value = payload.get(key);
+        String asString = value != null ? value.toString().trim() : null;
+        if (asString == null || asString.isEmpty()) {
+            throw new IllegalArgumentException("Missing required field '%s'".formatted(key));
+        }
+        return asString;
+    }
+
+    private static String extractOptionalString(Object value) {
+        if (value == null) {
+            return null;
+        }
+        String asString = value.toString().trim();
+        return asString.isEmpty() ? null : asString;
+    }
+
+    private static ObjectId extractObjectId(Object value, String fieldName) {
+        String candidate = extractOptionalString(value);
+        if (candidate == null) {
+            return null;
+        }
+        try {
+            return new ObjectId(candidate);
+        } catch (IllegalArgumentException ex) {
+            throw new IllegalArgumentException(
+                    "Field '%s' must be a valid MongoDB ObjectId".formatted(fieldName), ex);
+        }
+    }
+}

src/main/java/de/assecutor/votianlt/dto/ChatMessageOutboundPayload.java

@@ -0,0 +1,38 @@
+package de.assecutor.votianlt.dto;
+
+import de.assecutor.votianlt.model.Message;
+import de.assecutor.votianlt.model.MessageDirection;
+import de.assecutor.votianlt.model.MessageType;
+import java.time.LocalDateTime;
+
+/**
+ * Outbound chat message payload published to MQTT subscribers.
+ */
+public record ChatMessageOutboundPayload(
+        String messageId,
+        String sender,
+        String receiver,
+        String content,
+        MessageDirection direction,
+        MessageType messageType,
+        LocalDateTime createdAt,
+        String jobId,
+        String jobNumber,
+        boolean read
+) {
+
+    public static ChatMessageOutboundPayload fromMessage(Message message) {
+        return new ChatMessageOutboundPayload(
+                message.getIdAsString(),
+                message.getSender(),
+                message.getReceiver(),
+                message.getContent(),
+                message.getDirection(),
+                message.getMessageType(),
+                message.getCreatedAt(),
+                message.getJobIdAsString(),
+                message.getJobNumber(),
+                message.isRead()
+        );
+    }
+}

src/main/java/de/assecutor/votianlt/mqtt/MqttV5ClientManager.java

@@ -87,7 +87,7 @@ public class MqttV5ClientManager implements SmartLifecycle {
             // Subscribe to topics with QoS
             String[] topics = new String[] { "/server/+/task/photo/completed", "/server/+/task/confirm",
                     "/server/+/task/completed", "/server/+/task_completed", "/server/+/job/status",
-                    "/server/+/jobs/assigned", "/server/login" };
+                    "/server/+/jobs/assigned", "/server/+/message", "/server/login" };
             MqttQos qos = mapQos(props.getDefaultQos());
             for (String topic : topics) {
                 client.subscribeWith().topicFilter(topic).qos(qos).send().join();

src/main/java/de/assecutor/votianlt/pages/base/ui/view/MainLayout.java

@@ -29,6 +29,10 @@ import de.assecutor.votianlt.service.MessageService;
 
 import static com.vaadin.flow.theme.lumo.LumoUtility.*;
 
+import java.util.LinkedHashSet;
+import java.util.Optional;
+import java.util.Set;
+
 @AnonymousAllowed
 
 @Layout("main")
@@ -157,14 +161,9 @@ public final class MainLayout extends AppLayout {
         } else {
             item = new SideNavItem(menuEntry.title(), menuEntry.path());
         }
-        
-        // Add badge for "Nachrichten" menu item showing unread message count
         if ("Nachrichten".equals(menuEntry.title())) {
-            try {
+            long unreadCount = resolveUnreadMessageCount();
-                // Test: Show badge with 10 unread messages
+            if (unreadCount > 0) {
-                long unreadCount = 10;
-                
-                // Create blue badge with white text (same color as UserMessagesView)
                 Span badge = new Span(String.valueOf(unreadCount));
                 badge.getElement().getThemeList().add("badge");
                 badge.getStyle().set("background-color", "var(--lumo-primary-color)");
@@ -177,14 +176,50 @@ public final class MainLayout extends AppLayout {
                 badge.getStyle().set("text-align", "center");
 
                 item.setSuffixComponent(badge);
-            } catch (Exception e) {
-                // If there's an error, just don't show the badge
             }
         }
         
         return item;
     }
 
+    private long resolveUnreadMessageCount() {
+        if (!securityService.isUserLoggedIn()) {
+            return 0;
+        }
+
+        Set<String> candidateReceivers = new LinkedHashSet<>();
+
+        try {
+            User currentUser = securityService.getCurrentDatabaseUser();
+            if (currentUser != null) {
+                String email = Optional.ofNullable(currentUser.getEmail()).map(String::trim).orElse("");
+                if (!email.isBlank()) {
+                    candidateReceivers.add(email);
+                }
+                String fullName = ((Optional.ofNullable(currentUser.getFirstname()).orElse("") + " "
+                        + Optional.ofNullable(currentUser.getName()).orElse(""))).trim();
+                if (!fullName.isBlank()) {
+                    candidateReceivers.add(fullName);
+                }
+            }
+        } catch (RuntimeException ignored) {
+            // Fallback to username only
+        }
+
+        Optional.ofNullable(securityService.getCurrentUsername()).map(String::trim).filter(name -> !name.isBlank())
+                .ifPresent(candidateReceivers::add);
+
+        if (candidateReceivers.isEmpty()) {
+            return 0;
+        }
+
+        long unread = 0;
+        for (String receiver : candidateReceivers) {
+            unread += messageService.getUnreadMessageCount(receiver);
+        }
+        return unread;
+    }
+
     private Component createUserMenu() {
         var userMenu = new MenuBar();
         userMenu.addThemeVariants(MenuBarVariant.LUMO_TERTIARY_INLINE);

src/main/java/de/assecutor/votianlt/pages/view/MessageDetailsView.java

@@ -10,6 +10,8 @@ import com.vaadin.flow.component.icon.VaadinIcon;
 import com.vaadin.flow.component.orderedlayout.HorizontalLayout;
 import com.vaadin.flow.component.orderedlayout.Scroller;
 import com.vaadin.flow.component.orderedlayout.VerticalLayout;
+import com.vaadin.flow.component.notification.Notification;
+import com.vaadin.flow.component.notification.NotificationVariant;
 import com.vaadin.flow.component.textfield.TextArea;
 import com.vaadin.flow.router.BeforeEnterEvent;
 import com.vaadin.flow.router.BeforeEnterObserver;
@@ -17,13 +19,23 @@ import com.vaadin.flow.router.PageTitle;
 import com.vaadin.flow.router.Route;
 import com.vaadin.flow.router.RouteParameters;
 import de.assecutor.votianlt.model.AppUser;
+import de.assecutor.votianlt.model.Message;
+import de.assecutor.votianlt.model.MessageDirection;
+import de.assecutor.votianlt.model.MessageType;
 import de.assecutor.votianlt.pages.service.AppUserService;
+import de.assecutor.votianlt.service.MessageService;
+import de.assecutor.votianlt.security.SecurityService;
 import jakarta.annotation.security.RolesAllowed;
 import lombok.extern.slf4j.Slf4j;
 import org.bson.types.ObjectId;
 
+import java.time.LocalDate;
 import java.time.LocalDateTime;
 import java.time.format.DateTimeFormatter;
+import java.util.List;
+import java.util.Optional;
+import java.util.stream.Collectors;
+import java.util.Objects;
 
 @Route(value = "message-details/:clientId/:conversationId", layout = de.assecutor.votianlt.pages.base.ui.view.MainLayout.class)
 @PageTitle("Nachrichtenverlauf")
@@ -32,9 +44,14 @@ import java.time.format.DateTimeFormatter;
 public class MessageDetailsView extends Main implements BeforeEnterObserver {
 
     private final AppUserService appUserService;
+    private final MessageService messageService;
+    private final SecurityService securityService;
 
-    private String clientId;
+    private String participantKey;
     private String conversationId;
+    private boolean jobConversation;
+    private ObjectId jobIdContext;
+    private String jobNumberContext;
     private VerticalLayout contentLayout;
     private VerticalLayout messagesContainer;
     private Scroller messagesScroller;
@@ -42,8 +59,11 @@ public class MessageDetailsView extends Main implements BeforeEnterObserver {
     private static final DateTimeFormatter TIME_FORMATTER = DateTimeFormatter.ofPattern("HH:mm");
     private static final DateTimeFormatter DATE_FORMATTER = DateTimeFormatter.ofPattern("dd.MM.yyyy");
 
-    public MessageDetailsView(AppUserService appUserService) {
+    public MessageDetailsView(AppUserService appUserService, MessageService messageService,
+            SecurityService securityService) {
         this.appUserService = appUserService;
+        this.messageService = messageService;
+        this.securityService = securityService;
         
         // Set height to 100% to prevent page from growing beyond viewport
         setHeightFull();
@@ -64,13 +84,13 @@ public class MessageDetailsView extends Main implements BeforeEnterObserver {
         // Extract route parameters from URL
         RouteParameters parameters = event.getRouteParameters();
         
-        this.clientId = parameters.get("clientId").orElse(null);
+        this.participantKey = parameters.get("clientId").orElse(null);
         this.conversationId = parameters.get("conversationId").orElse(null);
 
-        log.info("MessageDetailsView - clientId: {}, conversationId: {}", clientId, conversationId);
+        log.info("MessageDetailsView - participant: {}, conversationId: {}", participantKey, conversationId);
 
-        if (clientId == null || conversationId == null) {
+        if (participantKey == null || conversationId == null) {
-            log.warn("Missing required route parameters: clientId={}, conversationId={}", clientId, conversationId);
+            log.warn("Missing required route parameters: participantKey={}, conversationId={}", participantKey, conversationId);
             event.rerouteToError(IllegalArgumentException.class, "Missing required parameters");
             return;
         }
@@ -81,29 +101,29 @@ public class MessageDetailsView extends Main implements BeforeEnterObserver {
     private void loadMessageDetails() {
         contentLayout.removeAll();
 
-        // Get client info
+        AppUser client = resolveParticipant();
-        AppUser client = null;
+        String clientName = client != null
-        try {
+                ? (Optional.ofNullable(client.getVorname()).orElse("") + " "
-            ObjectId objectId = new ObjectId(clientId);
+                        + Optional.ofNullable(client.getNachname()).orElse("")).trim()
-            client = appUserService.findById(objectId);
+                : Optional.ofNullable(participantKey).orElse("Unbekannter Teilnehmer");
-        } catch (Exception e) {
+        if (clientName.isBlank()) {
-            log.warn("Could not find client with id: {}", clientId);
+            clientName = Optional.ofNullable(client).map(AppUser::getBezeichnung).orElse("Unbekannter Teilnehmer");
         }
 
-        String clientName = client != null ? 
+        List<Message> allMessages = messageService.getMessagesForParticipantAscending(participantKey);
-            client.getVorname() + " " + client.getNachname() : "Unbekannter Client";
+        List<Message> filteredMessages = filterMessagesForConversation(allMessages, conversationId);
 
-        // Determine conversation title
+        this.jobConversation = conversationId != null && conversationId.startsWith("job-");
-        String conversationTitle = "Allgemeine Unterhaltung";
+        this.jobIdContext = filteredMessages.stream().map(Message::getJobId).filter(Objects::nonNull).findFirst()
-        if (conversationId != null && conversationId.startsWith("job-")) {
+                .orElse(null);
-            conversationTitle = "Auftrag #" + conversationId.substring(4);
+        this.jobNumberContext = filteredMessages.stream().map(Message::getJobNumber)
-        }
+                .filter(value -> value != null && !value.isBlank()).findFirst().orElse(null);
+
+        String conversationTitle = resolveConversationTitle(filteredMessages, conversationId);
 
-        // Create header
         HorizontalLayout headerLayout = createHeaderLayout(clientName, conversationTitle);
         contentLayout.add(headerLayout);
 
-        // Create messages container (content for scrollable area)
         messagesContainer = new VerticalLayout();
         messagesContainer.setPadding(true);
         messagesContainer.setSpacing(true);
@@ -111,26 +131,34 @@ public class MessageDetailsView extends Main implements BeforeEnterObserver {
         messagesContainer.getStyle().set("background-color", "#f0f0f0");
         messagesContainer.getStyle().set("border-radius", "8px");
         messagesContainer.getStyle().set("padding", "20px");
+        messagesContainer.setHeightFull();
+        messagesContainer.getStyle().set("min-height", "100%");
+        messagesContainer.getStyle().set("display", "flex");
+        messagesContainer.getStyle().set("flex-direction", "column");
+        messagesContainer.getStyle().set("flex", "1 1 auto");
 
-        // Add test messages
+        if (!filteredMessages.isEmpty()) {
-        loadTestMessages();
+            renderMessages(filteredMessages);
+        } else {
+            ensureScrollAnchor();
+        }
 
-        // Wrap messages container in Scroller for proper scrolling behavior
         messagesScroller = new Scroller(messagesContainer);
         messagesScroller.setWidthFull();
         messagesScroller.setScrollDirection(Scroller.ScrollDirection.VERTICAL);
+        messagesScroller.setHeightFull();
+        messagesScroller.getStyle().set("flex", "1 1 auto");
 
         contentLayout.add(messagesScroller);
         contentLayout.setFlexGrow(1, messagesScroller);
 
-        // Add message input area
         HorizontalLayout inputLayout = createMessageInputArea();
         contentLayout.add(inputLayout);
     }
 
     private HorizontalLayout createHeaderLayout(String clientName, String conversationTitle) {
         Button backButton = new Button("Zurück", VaadinIcon.ARROW_LEFT.create());
-        backButton.addClickListener(e -> UI.getCurrent().navigate("user-messages/" + clientId));
+        backButton.addClickListener(e -> UI.getCurrent().navigate("user-messages/" + participantKey));
         
         VerticalLayout titleLayout = new VerticalLayout();
         titleLayout.setPadding(false);
@@ -153,69 +181,6 @@ public class MessageDetailsView extends Main implements BeforeEnterObserver {
         return layout;
     }
 
-    private void loadTestMessages() {
-        // Test data - message thread
-        LocalDateTime now = LocalDateTime.now();
-        
-        // Day 1 - older messages
-        messagesContainer.add(createDateSeparator(now.minusDays(2)));
-        messagesContainer.add(createIncomingMessage(
-            "Hallo, ich habe eine Frage zum Auftrag.",
-            now.minusDays(2).withHour(10).withMinute(30)
-        ));
-        messagesContainer.add(createOutgoingMessage(
-            "Hallo! Gerne, wie kann ich Ihnen helfen?",
-            now.minusDays(2).withHour(10).withMinute(35)
-        ));
-        messagesContainer.add(createIncomingMessage(
-            "Wann wird die Lieferung voraussichtlich ankommen?",
-            now.minusDays(2).withHour(10).withMinute(40)
-        ));
-        messagesContainer.add(createOutgoingMessage(
-            "Die Lieferung ist für morgen zwischen 14:00 und 16:00 Uhr geplant.",
-            now.minusDays(2).withHour(10).withMinute(45)
-        ));
-        
-        // Day 2 - yesterday
-        messagesContainer.add(createDateSeparator(now.minusDays(1)));
-        messagesContainer.add(createIncomingMessage(
-            "Vielen Dank für die Information!",
-            now.minusDays(1).withHour(9).withMinute(15)
-        ));
-        messagesContainer.add(createOutgoingMessage(
-            "Gern geschehen! Melden Sie sich bei weiteren Fragen.",
-            now.minusDays(1).withHour(9).withMinute(20)
-        ));
-        
-        // Today
-        messagesContainer.add(createDateSeparator(now));
-        messagesContainer.add(createIncomingMessage(
-            "Die Lieferung ist angekommen. Alles perfekt!",
-            now.minusHours(2).withMinute(0)
-        ));
-        messagesContainer.add(createOutgoingMessage(
-            "Das freut mich zu hören! Vielen Dank für die Rückmeldung.",
-            now.minusHours(1).withMinute(30)
-        ));
-        messagesContainer.add(createIncomingMessage(
-            "Können wir für nächste Woche einen neuen Auftrag vereinbaren?",
-            now.minusMinutes(30)
-        ));
-        messagesContainer.add(createOutgoingMessage(
-            "Selbstverständlich! Ich erstelle Ihnen gleich ein Angebot.",
-            now.minusMinutes(15)
-        ));
-        
-        // Add scroll anchor at the end - this invisible element will be our scroll target
-        scrollAnchor = new Div();
-        scrollAnchor.setId("scroll-anchor");
-        scrollAnchor.getStyle().set("height", "1px");
-        messagesContainer.add(scrollAnchor);
-        
-        // Auto-scroll to bottom after messages are loaded
-        scrollToBottom();
-    }
-
     private Div createDateSeparator(LocalDateTime date) {
         Div separator = new Div();
         separator.setWidthFull();
@@ -309,12 +274,8 @@ public class MessageDetailsView extends Main implements BeforeEnterObserver {
         sendButton.addClickListener(e -> {
             String message = messageInput.getValue();
             if (message != null && !message.trim().isEmpty()) {
-                // Add message to view (test data)
+                sendMessageToParticipant(message.trim());
-                messagesContainer.add(createOutgoingMessage(message, LocalDateTime.now()));
                 messageInput.clear();
-                
-                // Scroll to bottom
-                scrollToBottom();
             }
         });
 
@@ -326,6 +287,151 @@ public class MessageDetailsView extends Main implements BeforeEnterObserver {
         return layout;
     }
 
+    private void sendMessageToParticipant(String content) {
+        String sender = Optional.ofNullable(securityService.getCurrentUsername()).filter(name -> !name.isBlank())
+                .orElse("System");
+
+        try {
+            Message saved;
+            if (jobConversation) {
+                saved = messageService.sendJobMessageToClient(content, sender, participantKey, jobIdContext,
+                        jobNumberContext);
+            } else {
+                saved = messageService.sendGeneralMessageToClient(content, sender, participantKey);
+            }
+
+            Notification.show("Nachricht gesendet", 2000, Notification.Position.BOTTOM_END)
+                    .addThemeVariants(NotificationVariant.LUMO_SUCCESS);
+
+            // Refresh conversation to include the new message and update counters
+            loadMessageDetails();
+
+        } catch (Exception ex) {
+            log.error("Failed to send message to {}: {}", participantKey, ex.getMessage(), ex);
+            Notification.show("Nachricht konnte nicht gesendet werden: " + ex.getMessage(), 4000,
+                    Notification.Position.MIDDLE)
+                    .addThemeVariants(NotificationVariant.LUMO_ERROR);
+        }
+    }
+
+    private AppUser resolveParticipant() {
+        if (participantKey == null || participantKey.isBlank()) {
+            return null;
+        }
+        try {
+            ObjectId objectId = new ObjectId(participantKey);
+            return appUserService.findById(objectId);
+        } catch (IllegalArgumentException ex) {
+            return appUserService.findAll().stream()
+                    .filter(user -> participantKey.equals(user.getEmail()) || participantKey.equals(user.getAppCode()))
+                    .findFirst()
+                    .orElse(null);
+        }
+    }
+
+    private List<Message> filterMessagesForConversation(List<Message> messages, String conversationId) {
+        if (conversationId == null || messages == null) {
+            return List.of();
+        }
+        if ("general".equalsIgnoreCase(conversationId)) {
+            return messages.stream()
+                    .filter(msg -> Optional.ofNullable(msg.getMessageType()).orElse(MessageType.GENERAL) == MessageType.GENERAL)
+                    .collect(Collectors.toList());
+        }
+        if (conversationId.startsWith("job-")) {
+            String token = conversationId.substring(4);
+            return messages.stream()
+                    .filter(msg -> Optional.ofNullable(msg.getMessageType()).orElse(MessageType.GENERAL) == MessageType.JOB_RELATED
+                            && matchesJobConversation(msg, token))
+                    .collect(Collectors.toList());
+        }
+        return messages;
+    }
+
+    private boolean matchesJobConversation(Message message, String token) {
+        if (token == null || token.isBlank() || message == null) {
+            return false;
+        }
+        String normalizedToken = token.toLowerCase();
+        String jobNumber = Optional.ofNullable(message.getJobNumber()).orElse("");
+        String jobId = Optional.ofNullable(message.getJobIdAsString()).orElse("");
+
+        return sanitize(jobNumber).equalsIgnoreCase(normalizedToken)
+                || sanitize(jobId).equalsIgnoreCase(normalizedToken)
+                || jobNumber.equalsIgnoreCase(token)
+                || jobId.equalsIgnoreCase(token);
+    }
+
+    private String sanitize(String value) {
+        if (value == null) {
+            return "";
+        }
+        return value.replaceAll("[^a-zA-Z0-9_-]", "_").toLowerCase();
+    }
+
+    private String resolveConversationTitle(List<Message> messages, String conversationId) {
+        if (conversationId == null) {
+            return "Konversation";
+        }
+        if ("general".equalsIgnoreCase(conversationId)) {
+            return "Allgemeine Unterhaltung";
+        }
+        if (conversationId.startsWith("job-")) {
+            if (messages != null && !messages.isEmpty()) {
+                for (Message message : messages) {
+                    String jobNumber = Optional.ofNullable(message.getJobNumber()).filter(s -> !s.isBlank()).orElse(null);
+                    if (jobNumber != null) {
+                        return "Auftrag " + jobNumber;
+                    }
+                    String jobId = Optional.ofNullable(message.getJobIdAsString()).filter(s -> !s.isBlank()).orElse(null);
+                    if (jobId != null) {
+                        return "Auftrag " + jobId;
+                    }
+                }
+            }
+            return "Auftragsbasierte Unterhaltung";
+        }
+        return "Konversation";
+    }
+
+    private void renderMessages(List<Message> messages) {
+        LocalDate currentDate = null;
+        for (Message message : messages) {
+            LocalDateTime timestamp = resolveTimestamp(message);
+            LocalDate messageDate = timestamp.toLocalDate();
+            if (!messageDate.equals(currentDate)) {
+                messagesContainer.add(createDateSeparator(timestamp));
+                currentDate = messageDate;
+            }
+
+            String content = Optional.ofNullable(message.getContent()).orElse("(kein Inhalt)");
+            if (message.getDirection() == MessageDirection.INCOMING) {
+                messagesContainer.add(createIncomingMessage(content, timestamp));
+            } else {
+                messagesContainer.add(createOutgoingMessage(content, timestamp));
+            }
+        }
+
+        ensureScrollAnchor();
+
+        scrollToBottom();
+    }
+
+    private LocalDateTime resolveTimestamp(Message message) {
+        return Optional.ofNullable(message.getCreatedAt()).orElse(LocalDateTime.now());
+    }
+
+    private void ensureScrollAnchor() {
+        if (scrollAnchor == null) {
+            scrollAnchor = new Div();
+            scrollAnchor.setId("scroll-anchor");
+            scrollAnchor.getStyle().set("height", "1px");
+        }
+        if (scrollAnchor.getParent().isEmpty()) {
+            messagesContainer.add(scrollAnchor);
+        }
+    }
+    
     /**
      * Scroll the messages scroller to the bottom to show the latest message
      * Uses scrollIntoView on the anchor element at the end of messages

src/main/java/de/assecutor/votianlt/pages/view/MessagesView.java

@@ -1,13 +1,12 @@
 package de.assecutor.votianlt.pages.view;
 
+import com.vaadin.flow.component.AttachEvent;
+import com.vaadin.flow.component.DetachEvent;
 import com.vaadin.flow.component.UI;
-import com.vaadin.flow.component.button.Button;
-import com.vaadin.flow.component.button.ButtonVariant;
 import com.vaadin.flow.component.grid.Grid;
 import com.vaadin.flow.component.html.H2;
 import com.vaadin.flow.component.html.Main;
 import com.vaadin.flow.component.html.Span;
-import com.vaadin.flow.component.icon.VaadinIcon;
 import com.vaadin.flow.component.notification.Notification;
 import com.vaadin.flow.component.notification.NotificationVariant;
 import com.vaadin.flow.component.orderedlayout.HorizontalLayout;
@@ -21,15 +20,20 @@ import de.assecutor.votianlt.model.AppUser;
 import de.assecutor.votianlt.model.Message;
 import de.assecutor.votianlt.model.MessageDirection;
 import de.assecutor.votianlt.pages.service.AppUserService;
-import de.assecutor.votianlt.repository.JobRepository;
-import de.assecutor.votianlt.security.SecurityService;
 import de.assecutor.votianlt.service.MessageService;
 import jakarta.annotation.security.RolesAllowed;
 import lombok.extern.slf4j.Slf4j;
 
 import java.time.format.DateTimeFormatter;
-import java.util.*;
+import java.time.LocalDateTime;
-import java.util.stream.Collectors;
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.concurrent.atomic.AtomicBoolean;
+import com.vaadin.flow.shared.Registration;
 
 @Route(value = "messages", layout = de.assecutor.votianlt.pages.base.ui.view.MainLayout.class)
 @PageTitle("Nachrichten")
@@ -38,20 +42,19 @@ import java.util.stream.Collectors;
 @Slf4j
 public class MessagesView extends Main {
 
+    private static final int POLL_INTERVAL_MS = 5000;
+
     private final MessageService messageService;
-    private final SecurityService securityService;
     private final AppUserService appUserService;
-    private final JobRepository jobRepository;
     
     private Grid<ClientMessageSummary> clientGrid;
     private static final DateTimeFormatter DATE_FORMATTER = DateTimeFormatter.ofPattern("dd.MM.yyyy HH:mm");
+    private final AtomicBoolean loading = new AtomicBoolean(false);
+    private Registration pollRegistration;
 
-    public MessagesView(MessageService messageService, SecurityService securityService, 
+    public MessagesView(MessageService messageService, AppUserService appUserService) {
-                       AppUserService appUserService, JobRepository jobRepository) {
         this.messageService = messageService;
-        this.securityService = securityService;
         this.appUserService = appUserService;
-        this.jobRepository = jobRepository;
 
         // Create main layout
         VerticalLayout layout = new VerticalLayout();
@@ -77,15 +80,9 @@ public class MessagesView extends Main {
 
     private HorizontalLayout createHeaderLayout() {
         H2 title = new H2("Nachrichten");
-        
+        HorizontalLayout layout = new HorizontalLayout(title);
-        Button refreshButton = new Button("Aktualisieren", VaadinIcon.REFRESH.create());
-        refreshButton.addClickListener(e -> loadClientSummaries());
-        
-        HorizontalLayout layout = new HorizontalLayout(title, refreshButton);
         layout.setWidthFull();
         layout.setAlignItems(com.vaadin.flow.component.orderedlayout.FlexComponent.Alignment.CENTER);
-        layout.expand(title);
-        
         return layout;
     }
 
@@ -144,162 +141,188 @@ public class MessagesView extends Main {
     }
 
     private void loadClientSummaries() {
+        if (!loading.compareAndSet(false, true)) {
+            return;
+        }
         try {
-            // Generate test data for display
+            List<AppUser> appUsers = Optional.ofNullable(appUserService.findByCurrentUser()).orElseGet(ArrayList::new);
-            List<ClientMessageSummary> summaries = generateTestData();
+            Map<String, AppUser> appUserLookup = buildAppUserLookup(appUsers);
+
+            List<Message> allMessages = messageService.getAllMessages();
+            Map<String, List<Message>> groupedByParticipant = groupMessagesByParticipant(allMessages);
+            List<ClientMessageSummary> summaries = buildSummaries(groupedByParticipant, appUserLookup, appUsers);
             clientGrid.setItems(summaries);
 
         } catch (Exception e) {
             log.error("Error loading client summaries: {}", e.getMessage(), e);
             Notification.show("Fehler beim Laden der Nachrichten", 3000, Notification.Position.MIDDLE)
                 .addThemeVariants(NotificationVariant.LUMO_ERROR);
+        } finally {
+            loading.set(false);
         }
     }
 
-    private List<ClientMessageSummary> generateTestData() {
+    private Map<String, List<Message>> groupMessagesByParticipant(List<Message> messages) {
-        List<ClientMessageSummary> summaries = new ArrayList<>();
+        Map<String, List<Message>> grouped = new LinkedHashMap<>();
-        
+        for (Message message : messages) {
-        // Test client 1 - Max Mustermann with unread messages
+            String participantKey = resolveParticipantKey(message);
-        summaries.add(new ClientMessageSummary(
+            if (participantKey == null || participantKey.isBlank()) {
-            "client001",
+                continue;
-            "Max Mustermann",
+            }
-            "max.mustermann@example.com",
+            grouped.computeIfAbsent(participantKey, key -> new ArrayList<>()).add(message);
-            15,
+        }
-            3,
+        return grouped;
-            java.time.LocalDateTime.now().minusHours(2),
-            "Hallo, ich habe eine Frage zu meinem letzten Auftrag..."
-        ));
-        
-        // Test client 2 - Anna Schmidt with no unread messages
-        summaries.add(new ClientMessageSummary(
-            "client002",
-            "Anna Schmidt",
-            "anna.schmidt@example.com",
-            8,
-            0,
-            java.time.LocalDateTime.now().minusDays(1),
-            "Vielen Dank für die schnelle Bearbeitung!"
-        ));
-        
-        // Test client 3 - Peter Weber with many unread messages
-        summaries.add(new ClientMessageSummary(
-            "client003",
-            "Peter Weber",
-            "peter.weber@example.com",
-            25,
-            7,
-            java.time.LocalDateTime.now().minusMinutes(30),
-            "Können Sie mir bitte den aktuellen Status mitteilen?"
-        ));
-        
-        // Test client 4 - Lisa Müller with recent message
-        summaries.add(new ClientMessageSummary(
-            "client004",
-            "Lisa Müller",
-            "lisa.mueller@example.com",
-            12,
-            1,
-            java.time.LocalDateTime.now().minusMinutes(5),
-            "Wann wird die Lieferung ankommen?"
-        ));
-        
-        // Test client 5 - Thomas Becker with older messages
-        summaries.add(new ClientMessageSummary(
-            "client005",
-            "Thomas Becker",
-            "thomas.becker@example.com",
-            20,
-            0,
-            java.time.LocalDateTime.now().minusDays(5),
-            "Alles erledigt, danke für die Zusammenarbeit."
-        ));
-        
-        // Test client 6 - Sarah Wagner with unread messages
-        summaries.add(new ClientMessageSummary(
-            "client006",
-            "Sarah Wagner",
-            "sarah.wagner@example.com",
-            6,
-            2,
-            java.time.LocalDateTime.now().minusHours(8),
-            "Gibt es Updates zum Auftrag #12345?"
-        ));
-        
-        return summaries;
     }
 
-    private List<ClientMessageSummary> aggregateMessagesByClient(String currentUsername) {
+    private List<ClientMessageSummary> buildSummaries(Map<String, List<Message>> groupedMessages,
-        // Get all messages for current user (received and sent)
+            Map<String, AppUser> appUserLookup, List<AppUser> appUsers) {
-        List<Message> receivedMessages = messageService.getMessagesForReceiver(currentUsername);
+        Map<String, ClientMessageSummary> summaryMap = new LinkedHashMap<>();
-        List<Message> sentMessages = messageService.getMessagesByDirection(MessageDirection.OUTGOING)
-            .stream()
-            .filter(m -> currentUsername.equals(m.getSender()))
-            .toList();
 
-        List<Message> allMessages = new ArrayList<>();
+        for (Map.Entry<String, List<Message>> entry : groupedMessages.entrySet()) {
-        allMessages.addAll(receivedMessages);
+            String participantKey = entry.getKey();
-        allMessages.addAll(sentMessages);
+            AppUser participant = resolveAppUser(participantKey, appUserLookup);
+            if (participant == null) {
+                continue; // Only display app users of the current account holder
+            }
 
-        // Group messages by client (sender or receiver that is not the current user)
+            String participantId = participant.getIdAsString();
-        Map<String, List<Message>> messagesByClient = allMessages.stream()
+            if (participantId == null || participantId.isBlank()) {
-            .collect(Collectors.groupingBy(message -> {
+                continue;
-                // Determine the "other party" (client)
+            }
-                if (currentUsername.equals(message.getSender())) {
-                    return message.getReceiver();
-                } else {
-                    return message.getSender();
-                }
-            }));
 
-        // Create summaries for each client
+            ClientMessageSummary summary = summaryMap.computeIfAbsent(participantId,
-        List<ClientMessageSummary> summaries = new ArrayList<>();
+                    id -> createEmptySummary(participant));
-        for (Map.Entry<String, List<Message>> entry : messagesByClient.entrySet()) {
-            String clientEmail = entry.getKey();
-            List<Message> clientMessages = entry.getValue();
 
-            // Find client info
+            List<Message> conversation = entry.getValue();
-            AppUser appUser = appUserService.findAll().stream()
+            if (conversation == null || conversation.isEmpty()) {
-                .filter(u -> clientEmail.equals(u.getEmail()))
+                continue;
-                .findFirst()
+            }
-                .orElse(null);
 
-            String clientName = appUser != null ? 
+            conversation.sort(Comparator.comparing(Message::getCreatedAt,
-                appUser.getVorname() + " " + appUser.getNachname() : clientEmail;
+                    Comparator.nullsLast(LocalDateTime::compareTo)).reversed());
-            String clientId = appUser != null ? appUser.getIdAsString() : clientEmail;
 
-            // Calculate statistics
+            Message latest = conversation.stream()
-            int totalMessages = clientMessages.size();
+                    .filter(msg -> msg.getCreatedAt() != null)
-            long unreadCount = clientMessages.stream()
+                    .findFirst()
-                .filter(m -> !m.isRead() && currentUsername.equals(m.getReceiver()))
+                    .orElse(conversation.get(0));
-                .count();
 
-            // Get last message
+            LocalDateTime lastDate = latest.getCreatedAt();
-            Message lastMessage = clientMessages.stream()
+            String preview = Optional.ofNullable(latest.getContent()).filter(s -> !s.isBlank()).orElse("(kein Inhalt)");
-                .max(Comparator.comparing(Message::getCreatedAt))
+            int totalMessages = conversation.size();
-                .orElse(null);
+            int unreadCount = (int) conversation.stream()
+                    .filter(msg -> msg.getDirection() == MessageDirection.INCOMING && !msg.isRead())
+                    .count();
 
-            java.time.LocalDateTime lastMessageDate = lastMessage != null ? lastMessage.getCreatedAt() : null;
+            summary.setTotalMessages(summary.getTotalMessages() + totalMessages);
-            String lastMessagePreview = lastMessage != null ? lastMessage.getContent() : null;
+            summary.setUnreadCount(summary.getUnreadCount() + unreadCount);
 
-            summaries.add(new ClientMessageSummary(
+            LocalDateTime currentLast = summary.getLastMessageDate();
-                clientId,
+            if (lastDate != null && (currentLast == null || lastDate.isAfter(currentLast))) {
-                clientName,
+                summary.setLastMessageDate(lastDate);
-                clientEmail,
+                summary.setLastMessagePreview(preview);
-                totalMessages,
+            }
-                (int) unreadCount,
-                lastMessageDate,
-                lastMessagePreview
-            ));
         }
 
-        // Sort by last message date (most recent first)
+        for (AppUser appUser : appUsers) {
-        summaries.sort((s1, s2) -> {
+            if (appUser == null) {
-            if (s1.getLastMessageDate() == null) return 1;
+                continue;
-            if (s2.getLastMessageDate() == null) return -1;
+            }
-            return s2.getLastMessageDate().compareTo(s1.getLastMessageDate());
+            String appUserId = appUser.getIdAsString();
-        });
+            if (appUserId != null && !summaryMap.containsKey(appUserId)) {
+                summaryMap.put(appUserId, createEmptySummary(appUser));
+            }
+        }
 
+        List<ClientMessageSummary> summaries = new ArrayList<>(summaryMap.values());
+        summaries.sort(Comparator.comparing(ClientMessageSummary::getLastMessageDate,
+                Comparator.nullsLast(LocalDateTime::compareTo)).reversed());
         return summaries;
     }
 
+    private String resolveParticipantKey(Message message) {
+        if (message == null) {
+            return null;
+        }
+        if (message.getDirection() == MessageDirection.INCOMING) {
+            return message.getSender();
+        }
+        return message.getReceiver();
+    }
+
+    private AppUser resolveAppUser(String participantKey, Map<String, AppUser> appUserLookup) {
+        if (participantKey == null || participantKey.isBlank()) {
+            return null;
+        }
+        String trimmed = participantKey.trim();
+        AppUser directMatch = appUserLookup.get(trimmed);
+        if (directMatch != null) {
+            return directMatch;
+        }
+        return appUserLookup.get(trimmed.toLowerCase());
+    }
+
+    private String buildClientName(AppUser participant) {
+        if (participant == null) {
+            return "-";
+        }
+        String vorname = Optional.ofNullable(participant.getVorname()).orElse("").trim();
+        String nachname = Optional.ofNullable(participant.getNachname()).orElse("").trim();
+
+        String fullName = (vorname + " " + nachname).trim();
+        if (!fullName.isEmpty()) {
+            return fullName;
+        }
+        return Optional.ofNullable(participant.getBezeichnung()).orElse(participant.getIdAsString());
+    }
+
+    private ClientMessageSummary createEmptySummary(AppUser appUser) {
+        String clientId = Optional.ofNullable(appUser.getIdAsString()).orElse("-");
+        String clientName = buildClientName(appUser);
+        String clientEmail = Optional.ofNullable(appUser.getEmail()).orElse("-");
+        return new ClientMessageSummary(clientId, clientName, clientEmail, 0, 0, null, "-");
+    }
+
+    private Map<String, AppUser> buildAppUserLookup(List<AppUser> appUsers) {
+        Map<String, AppUser> lookup = new LinkedHashMap<>();
+        for (AppUser appUser : appUsers) {
+            if (appUser == null) {
+                continue;
+            }
+            addLookupEntry(lookup, appUser.getIdAsString(), appUser);
+            addLookupEntry(lookup, appUser.getEmail(), appUser);
+            addLookupEntry(lookup, appUser.getAppCode(), appUser);
+        }
+        return lookup;
+    }
+
+    private void addLookupEntry(Map<String, AppUser> lookup, String key, AppUser appUser) {
+        if (key == null) {
+            return;
+        }
+        String trimmed = key.trim();
+        if (trimmed.isEmpty()) {
+            return;
+        }
+        lookup.putIfAbsent(trimmed, appUser);
+        lookup.putIfAbsent(trimmed.toLowerCase(), appUser);
+    }
+
+    @Override
+    protected void onAttach(AttachEvent attachEvent) {
+        super.onAttach(attachEvent);
+        UI ui = attachEvent.getUI();
+        ui.setPollInterval(POLL_INTERVAL_MS);
+        pollRegistration = ui.addPollListener(event -> loadClientSummaries());
+        loadClientSummaries();
+    }
+
+    @Override
+    protected void onDetach(DetachEvent detachEvent) {
+        super.onDetach(detachEvent);
+        if (pollRegistration != null) {
+            pollRegistration.remove();
+            pollRegistration = null;
+        }
+        detachEvent.getUI().setPollInterval(-1);
+    }
 }

src/main/java/de/assecutor/votianlt/pages/view/UserMessagesView.java

@@ -16,13 +16,24 @@ import com.vaadin.flow.router.HasUrlParameter;
 import com.vaadin.flow.router.PageTitle;
 import com.vaadin.flow.router.Route;
 import de.assecutor.votianlt.model.AppUser;
+import de.assecutor.votianlt.model.Message;
+import de.assecutor.votianlt.model.MessageDirection;
+import de.assecutor.votianlt.model.MessageType;
 import de.assecutor.votianlt.pages.service.AppUserService;
+import de.assecutor.votianlt.service.MessageService;
 import jakarta.annotation.security.RolesAllowed;
 import lombok.extern.slf4j.Slf4j;
 import org.bson.types.ObjectId;
 
 import java.time.LocalDateTime;
 import java.time.format.DateTimeFormatter;
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.stream.Collectors;
 
 @Route(value = "user-messages", layout = de.assecutor.votianlt.pages.base.ui.view.MainLayout.class)
 @PageTitle("Nachrichten")
@@ -31,13 +42,15 @@ import java.time.format.DateTimeFormatter;
 public class UserMessagesView extends Main implements HasUrlParameter<String> {
 
     private final AppUserService appUserService;
+    private final MessageService messageService;
 
-    private String clientId;
+    private String participantKey;
     private VerticalLayout contentLayout;
     private static final DateTimeFormatter DATE_FORMATTER = DateTimeFormatter.ofPattern("dd.MM.yyyy HH:mm");
 
-    public UserMessagesView(AppUserService appUserService) {
+    public UserMessagesView(AppUserService appUserService, MessageService messageService) {
         this.appUserService = appUserService;
+        this.messageService = messageService;
         
         // Create main layout
         contentLayout = new VerticalLayout();
@@ -50,7 +63,7 @@ public class UserMessagesView extends Main implements HasUrlParameter<String> {
 
     @Override
     public void setParameter(BeforeEvent event, String parameter) {
-        this.clientId = parameter;
+        this.participantKey = parameter;
         loadClientMessages();
     }
 
@@ -60,24 +73,25 @@ public class UserMessagesView extends Main implements HasUrlParameter<String> {
         // Get client info
         AppUser client = null;
         try {
-            ObjectId objectId = new ObjectId(clientId);
+            ObjectId objectId = new ObjectId(participantKey);
             client = appUserService.findById(objectId);
         } catch (Exception e) {
-            log.warn("Could not find client with id: {}", clientId);
+            log.debug("Could not resolve AppUser for participant key {}: {}", participantKey, e.getMessage());
         }
 
         String clientName = client != null ? 
-            client.getVorname() + " " + client.getNachname() : "Unbekannter Client";
+            client.getVorname() + " " + client.getNachname() : Optional.ofNullable(participantKey).orElse("Unbekannter Teilnehmer");
 
-        // Create header
         HorizontalLayout headerLayout = createHeaderLayout(clientName);
         contentLayout.add(headerLayout);
 
-        // Create section for general messages (only one chat for general conversation)
+        List<Message> conversation = messageService.getMessagesForParticipantAscending(participantKey);
-        VerticalLayout generalSection = createGeneralMessagesSection();
+        Map<MessageType, List<Message>> messagesByType = conversation.stream()
+                .collect(Collectors.groupingBy(message -> Optional.ofNullable(message.getMessageType()).orElse(MessageType.GENERAL)));
 
-        // Create section for job-related messages
+        VerticalLayout generalSection = createGeneralMessagesSection(messagesByType.get(MessageType.GENERAL));
-        VerticalLayout jobSection = createJobMessagesSection();
+
+        VerticalLayout jobSection = createJobMessagesSection(messagesByType.get(MessageType.JOB_RELATED));
 
         contentLayout.add(generalSection, jobSection);
     }
@@ -96,7 +110,7 @@ public class UserMessagesView extends Main implements HasUrlParameter<String> {
         return layout;
     }
 
-    private VerticalLayout createGeneralMessagesSection() {
+    private VerticalLayout createGeneralMessagesSection(List<Message> generalMessages) {
         VerticalLayout section = new VerticalLayout();
         section.setPadding(true);
         section.setSpacing(true);
@@ -108,20 +122,34 @@ public class UserMessagesView extends Main implements HasUrlParameter<String> {
         H3 title = new H3("Allgemeine Nachrichten");
         section.add(title);
 
-        // Test data - only one general chat conversation
+        List<Message> sortedMessages = new ArrayList<>();
+        if (generalMessages != null) {
+            sortedMessages.addAll(generalMessages);
+        }
+
+        sortedMessages.sort(Comparator.comparing(Message::getCreatedAt, Comparator.nullsLast(LocalDateTime::compareTo)));
+
+        Message latest = sortedMessages.isEmpty() ? null : sortedMessages.get(sortedMessages.size() - 1);
+        int unreadCount = (int) sortedMessages.stream()
+                .filter(message -> message.getDirection() == MessageDirection.INCOMING && !message.isRead())
+                .count();
+        int messageCount = sortedMessages.size();
+        LocalDateTime lastMessageTime = latest != null ? latest.getCreatedAt() : null;
+        String preview = latest != null ? latest.getContent() : null;
+
         section.add(createMessageCard(
-            "Allgemeine Unterhaltung",
+                "Allgemeine Unterhaltung",
-            "Hallo, wie geht es Ihnen?",
+                preview,
-            LocalDateTime.now().minusHours(2),
+                lastMessageTime,
-            5,
+                messageCount,
-            2,
+                unreadCount,
-            "general"
+                "general"
         ));
 
         return section;
     }
 
-    private VerticalLayout createJobMessagesSection() {
+    private VerticalLayout createJobMessagesSection(List<Message> jobMessages) {
         VerticalLayout section = new VerticalLayout();
         section.setPadding(true);
         section.setSpacing(true);
@@ -133,40 +161,38 @@ public class UserMessagesView extends Main implements HasUrlParameter<String> {
         H3 title = new H3("Nachrichten zu Aufträgen");
         section.add(title);
 
-        // Test data - job-related messages
+        if (jobMessages == null || jobMessages.isEmpty()) {
-        section.add(createMessageCard(
+            section.add(new Span("Keine auftragsbezogenen Nachrichten vorhanden."));
-            "Auftrag #12345",
+            return section;
-            "Die Lieferung ist angekommen.",
+        }
-            LocalDateTime.now().minusHours(5),
-            8,
-            1,
-            "job-12345"
-        ));
 
-        section.add(createMessageCard(
+        Map<String, List<Message>> messagesByJob = jobMessages.stream()
-            "Auftrag #12344",
+                .collect(Collectors.groupingBy(this::resolveJobKey, LinkedHashMap::new, Collectors.toList()));
-            "Bitte um Rückruf bezüglich der Abholung.",
-            LocalDateTime.now().minusDays(2),
-            12,
-            3,
-            "job-12344"
-        ));
 
-        section.add(createMessageCard(
+        messagesByJob.forEach((jobKey, messages) -> {
-            "Auftrag #12343",
+            messages.sort(Comparator.comparing(Message::getCreatedAt, Comparator.nullsLast(LocalDateTime::compareTo)));
-            "Auftrag wurde erfolgreich abgeschlossen.",
+            Message latest = messages.get(messages.size() - 1);
-            LocalDateTime.now().minusDays(3),
+            int unreadCount = (int) messages.stream()
-            6,
+                    .filter(message -> message.getDirection() == MessageDirection.INCOMING && !message.isRead())
-            0,
+                    .count();
-            "job-12343"
+
-        ));
+            String conversationTitle = "Auftrag " + jobKey;
+            section.add(createMessageCard(
+                    conversationTitle,
+                    Optional.ofNullable(latest.getContent()).orElse(""),
+                    latest.getCreatedAt(),
+                    messages.size(),
+                    unreadCount,
+                    "job-" + sanitizeConversationId(jobKey)
+            ));
+        });
 
         return section;
     }
 
     private Div createMessageCard(String conversationTitle, String lastMessagePreview,
-                                   LocalDateTime lastMessageTime, int messageCount, 
+            LocalDateTime lastMessageTime, int messageCount,
-                                   int unreadCount, String conversationId) {
+            int unreadCount, String conversationId) {
         Div card = new Div();
         card.setWidthFull();
         card.getStyle().set("padding", "15px");
@@ -211,7 +237,7 @@ public class UserMessagesView extends Main implements HasUrlParameter<String> {
         titleRow.expand(titleSpan);
         
         // Preview text
-        Span preview = new Span(lastMessagePreview);
+        Span preview = new Span(Optional.ofNullable(lastMessagePreview).filter(s -> !s.isBlank()).orElse("(kein Inhalt)"));
         preview.getStyle().set("color", "#666666");
         preview.getStyle().set("font-size", "14px");
         
@@ -219,7 +245,7 @@ public class UserMessagesView extends Main implements HasUrlParameter<String> {
         HorizontalLayout metaRow = new HorizontalLayout();
         metaRow.setWidthFull();
         
-        Span timeSpan = new Span(lastMessageTime.format(DATE_FORMATTER));
+        Span timeSpan = new Span(lastMessageTime != null ? lastMessageTime.format(DATE_FORMATTER) : "-");
         timeSpan.getStyle().set("color", "#999999");
         timeSpan.getStyle().set("font-size", "12px");
         
@@ -238,10 +264,30 @@ public class UserMessagesView extends Main implements HasUrlParameter<String> {
         card.add(cardContent);
         
         // Click listener to navigate to message details
-        card.addClickListener(e -> {
+        card.addClickListener(e -> UI.getCurrent().navigate("message-details/" + participantKey + "/" + conversationId));
-            UI.getCurrent().navigate("message-details/" + clientId + "/" + conversationId);
-        });
 
         return card;
     }
+
+    private String resolveJobKey(Message message) {
+        if (message == null) {
+            return "Unbekannt";
+        }
+        String jobNumber = Optional.ofNullable(message.getJobNumber()).filter(s -> !s.isBlank()).orElse(null);
+        if (jobNumber != null) {
+            return jobNumber;
+        }
+        String jobId = message.getJobIdAsString();
+        if (jobId != null && !jobId.isBlank()) {
+            return jobId;
+        }
+        return "Unbekannt";
+    }
+
+    private String sanitizeConversationId(String value) {
+        if (value == null || value.isBlank()) {
+            return "unknown";
+        }
+        return value.replaceAll("[^a-zA-Z0-9_-]", "_");
+    }
 }

src/main/java/de/assecutor/votianlt/repository/MessageRepository.java

@@ -61,4 +61,16 @@ public interface MessageRepository extends MongoRepository<Message, ObjectId> {
      * Find all messages (for admin/overview), ordered by creation time descending
      */
     List<Message> findAllByOrderByCreatedAtDesc();
+
+    /**
+     * Find all messages where the sender or receiver matches the provided value,
+     * ordered by creation time ascending.
+     */
+    List<Message> findBySenderOrReceiverOrderByCreatedAtAsc(String sender, String receiver);
+
+    /**
+     * Find all messages where the sender or receiver matches the provided value,
+     * ordered by creation time descending.
+     */
+    List<Message> findBySenderOrReceiverOrderByCreatedAtDesc(String sender, String receiver);
 }

src/main/java/de/assecutor/votianlt/service/MessageService.java

@@ -1,19 +1,18 @@
 package de.assecutor.votianlt.service;
 
-import com.fasterxml.jackson.databind.ObjectMapper;
 import de.assecutor.votianlt.model.Message;
 import de.assecutor.votianlt.model.MessageDirection;
 import de.assecutor.votianlt.model.MessageType;
+import de.assecutor.votianlt.dto.ChatMessageInboundPayload;
+import de.assecutor.votianlt.dto.ChatMessageOutboundPayload;
 import de.assecutor.votianlt.mqtt.MqttPublisher;
 import de.assecutor.votianlt.repository.MessageRepository;
 import lombok.extern.slf4j.Slf4j;
 import org.bson.types.ObjectId;
 import org.springframework.stereotype.Service;
 
-import java.nio.charset.StandardCharsets;
+import java.util.Collections;
-import java.util.HashMap;
 import java.util.List;
-import java.util.Map;
 import java.util.Optional;
 
 @Service
@@ -22,12 +21,9 @@ public class MessageService {
 
     private final MessageRepository messageRepository;
     private final MqttPublisher mqttPublisher;
-    private final ObjectMapper objectMapper;
-
     public MessageService(MessageRepository messageRepository, MqttPublisher mqttPublisher) {
         this.messageRepository = messageRepository;
         this.mqttPublisher = mqttPublisher;
-        this.objectMapper = new ObjectMapper();
     }
 
     /**
@@ -62,13 +58,14 @@ public class MessageService {
     /**
      * Handle incoming message from a client
      */
-    public Message receiveMessageFromClient(String content, String sender, String receiver, 
+    public Message receiveMessageFromClient(ChatMessageInboundPayload payload) {
-                                           ObjectId jobId, String jobNumber) {
         Message message;
-        if (jobId != null) {
+        if (payload.hasJobContext()) {
-            message = new Message(content, sender, receiver, MessageDirection.INCOMING, jobId, jobNumber);
+            message = new Message(payload.content(), payload.sender(), payload.receiver(),
+                    MessageDirection.INCOMING, payload.jobId(), payload.jobNumber());
         } else {
-            message = new Message(content, sender, receiver, MessageDirection.INCOMING);
+            message = new Message(payload.content(), payload.sender(), payload.receiver(),
+                    MessageDirection.INCOMING);
         }
         return saveMessage(message);
     }
@@ -79,18 +76,7 @@ public class MessageService {
     private void publishMessageToMqtt(Message message, String receiver) {
         try {
             String topic = "/client/" + receiver + "/message";
-            Map<String, Object> payload = new HashMap<>();
+            ChatMessageOutboundPayload payload = ChatMessageOutboundPayload.fromMessage(message);
-            payload.put("messageId", message.getIdAsString());
-            payload.put("content", message.getContent());
-            payload.put("sender", message.getSender());
-            payload.put("messageType", message.getMessageType().toString());
-            payload.put("createdAt", message.getCreatedAt().toString());
-            
-            if (message.getJobId() != null) {
-                payload.put("jobId", message.getJobIdAsString());
-                payload.put("jobNumber", message.getJobNumber());
-            }
-            
             mqttPublisher.publishAsJson(topic, payload, false);
             log.info("Published message to MQTT topic: {}", topic);
         } catch (Exception e) {
@@ -126,6 +112,28 @@ public class MessageService {
         return messageRepository.findByReceiverAndJobIdOrderByCreatedAtDesc(receiver, jobId);
     }
 
+    /**
+     * Get all messages a participant sent or received (oldest first) to reconstruct
+     * the conversation timeline.
+     */
+    public List<Message> getMessagesForParticipantAscending(String participant) {
+        if (participant == null || participant.isBlank()) {
+            return Collections.emptyList();
+        }
+        return messageRepository.findBySenderOrReceiverOrderByCreatedAtAsc(participant, participant);
+    }
+
+    /**
+     * Get all messages a participant sent or received (newest first) for
+     * quick summaries.
+     */
+    public List<Message> getMessagesForParticipantDescending(String participant) {
+        if (participant == null || participant.isBlank()) {
+            return Collections.emptyList();
+        }
+        return messageRepository.findBySenderOrReceiverOrderByCreatedAtDesc(participant, participant);
+    }
+
     /**
      * Get all general messages for a receiver
      */

src/main/resources/mqtt/chat/incoming-chat-message.json

@@ -0,0 +1,7 @@
+{
+  "sender": "driver01",
+  "receiver": "dispatcher01",
+  "content": "Ankunft in 10 Minuten.",
+  "jobId": "665f1c601971c8390b29f1f5",
+  "jobNumber": "JOB-2024-00042"
+}

src/main/resources/mqtt/chat/outgoing-chat-message.json

@@ -0,0 +1,12 @@
+{
+  "messageId": "6660d4c1fcb75a64f1b3c812",
+  "sender": "dispatcher01",
+  "receiver": "driver01",
+  "content": "Bitte bestätige die Lieferung.",
+  "direction": "OUTGOING",
+  "messageType": "JOB_RELATED",
+  "createdAt": "2024-05-25T10:45:00",
+  "jobId": "665f1c601971c8390b29f1f5",
+  "jobNumber": "JOB-2024-00042",
+  "read": false
+}