From 5e90c3b8ba0eb9fa0ba17c5f73568de817dcaf45 Mon Sep 17 00:00:00 2001
From: Markus Thielker <markus@thielker.dev>
Date: Wed, 30 Jul 2025 13:11:19 +0200
Subject: [PATCH 1/3] HL7-3: add new message type

---
 packages/shared/types.ts | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/packages/shared/types.ts b/packages/shared/types.ts
index 12a45fb..55a912a 100644
--- a/packages/shared/types.ts
+++ b/packages/shared/types.ts
@@ -11,6 +11,7 @@ export enum MessageType {
     assign_id = 'assign_id',
     send_hl7v2 = 'send_hl7v2',
     receive_hl7v2 = 'receive_hl7v2',
+    delivery_success = 'delivery_success',
     delivery_error = 'delivery_error',
 }
 
@@ -19,7 +20,9 @@ export type Message =
     | { type: MessageType.assign_id, payload: { stationId: string }}
     | { type: MessageType.send_hl7v2, payload: { message: string }}
     | { type: MessageType.receive_hl7v2, payload: { message: string, timestamp: string }}
+    | { type: MessageType.delivery_success, payload: { message: string, timestamp: string }}
     | { type: MessageType.delivery_error, payload: { error: string }}
 
 // required to define list of this message type
 export type ReceiveHl7v2Message = Extract<Message, { type: MessageType.receive_hl7v2 }>;
+export type DeliverySuccessMessage = Extract<Message, { type: MessageType.delivery_success }>;

From a892cbba46d6da77df55933dd42f912f4f486410 Mon Sep 17 00:00:00 2001
From: Markus Thielker <markus@thielker.dev>
Date: Wed, 30 Jul 2025 13:12:06 +0200
Subject: [PATCH 2/3] HL7-3: send ack-message to sending client on delivery

---
 packages/server/index.ts | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/packages/server/index.ts b/packages/server/index.ts
index acbf484..5955eb1 100644
--- a/packages/server/index.ts
+++ b/packages/server/index.ts
@@ -39,7 +39,7 @@ const clients = new Map();
 
 console.log(`Starting WebSocket server ...`);
 
-console.log("Server configuration:", config);
+console.log('Server configuration:', config);
 
 wss.on('connection', (ws) => {
 
@@ -105,17 +105,29 @@ wss.on('connection', (ws) => {
                 // check if recipient exists and is connected
                 if (recipientWs && recipientWs.readyState === WebSocket.OPEN) {
 
+                    const timestamp = new Date().toISOString();
+
                     // The recipient is connected. Forward the message.
                     const forwardMessage = {
                         type: MessageType.receive_hl7v2,
                         payload: {
                             message: message,
-                            timestamp: new Date().toISOString(),
+                            timestamp: timestamp,
                         },
                     } as Message;
                     recipientWs.send(JSON.stringify(forwardMessage));
                     console.log(`Forwarded message to ${recipientId}`);
 
+                    const ackMessage = {
+                        type: MessageType.delivery_success,
+                        payload: {
+                            message: message,
+                            timestamp: timestamp,
+                        },
+                    };
+                    ws.send(JSON.stringify(ackMessage));
+                    console.log(`Sent acknowledgment to ${stationId}`);
+
                 } else {
 
                     // The recipient is not connected or not found.

From fec77b73c3d1db5e63182cda2129e0c6fe2cf0f8 Mon Sep 17 00:00:00 2001
From: Markus Thielker <markus@thielker.dev>
Date: Wed, 30 Jul 2025 13:15:56 +0200
Subject: [PATCH 3/3] HL7-3: remove optimistic updates and react to
 delivery-success

---
 packages/client/src/routes/+page.svelte | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/packages/client/src/routes/+page.svelte b/packages/client/src/routes/+page.svelte
index 585b194..43ca8ee 100644
--- a/packages/client/src/routes/+page.svelte
+++ b/packages/client/src/routes/+page.svelte
@@ -9,7 +9,13 @@
         UnplugIcon,
         UserIcon,
     } from '@lucide/svelte';
-    import { ConnectionState, type Message, MessageType, type ReceiveHl7v2Message } from '@hnu.de/hl7v2-shared';
+    import {
+        ConnectionState,
+        type DeliverySuccessMessage,
+        type Message,
+        MessageType,
+        type ReceiveHl7v2Message,
+    } from '@hnu.de/hl7v2-shared';
     import { Button } from '$lib/components/ui/button';
     import { Card, CardContent, CardHeader } from '$lib/components/ui/card';
     import { Input } from '$lib/components/ui/input';
@@ -25,7 +31,7 @@
 
     // client state
     let composedMessage = $state(''); // content of text-box
-    let sentMessages = $state<ReceiveHl7v2Message[]>([]); // sent messages stored as type ReceiveHl7v2Message because of the timestamp
+    let sentMessages = $state<DeliverySuccessMessage[]>([]);
     let receivedMessages = $state<ReceiveHl7v2Message[]>([]);
     let isSending = $state(false);
     let copySuccess = $state(false);
@@ -96,6 +102,12 @@
                     receivedMessages = [message, ...receivedMessages];
                     break;
 
+                // our message was successfully delivered
+                case MessageType.delivery_success:
+                    sentMessages = [message, ...sentMessages];
+                    isSending = false
+                    break;
+
                 // message from server due to delivery error
                 case MessageType.delivery_error:
                     deliveryError = message.payload.error;
@@ -154,15 +166,6 @@
             payload: { message },
         } as Message;
         ws.send(JSON.stringify(messageToSend));
-
-        sentMessages = [{
-            type: MessageType.receive_hl7v2,
-            payload: { message, timestamp: new Date().toISOString() },
-        } as ReceiveHl7v2Message, ...sentMessages];
-        composedMessage = segmentTemplates.MSH.template();
-
-        // reset UI state
-        isSending = false;
     }
 
     // copies the stationId to the clipboard and handles UI state