[core] Implement message deduplication to prevent duplicate webhooks in GOWS (#1718)

fix #1564

Author: mahmouds12

src/core/engines/gows/session.gows.core.ts

@@ -161,7 +161,7 @@ import { isFromFullSync } from '@waha/core/engines/gows/appstate';
 import { toVcardV3 } from '@waha/core/vcard';
 import { AckToStatus } from '@waha/core/utils/acks';
 import { ParseEventResponseType } from '@waha/core/utils/events';
-import { DistinctAck } from '@waha/core/utils/reactive';
+import { DistinctAck, DistinctMessages } from '@waha/core/utils/reactive';
 import { Label, LabelDTO, LabelID } from '@waha/structures/labels.dto';
 import { LidToPhoneNumber } from '@waha/structures/lids.dto';
 import { exclude } from '@waha/utils/reactive/ops/exclude';
@@ -477,6 +477,10 @@ export class WhatsappSessionGoWSCore extends WhatsappSession {
         return msg;
       }),
       mergeMap((msg) => this.processIncomingMessage(msg, true)),
+      filter(Boolean),
+      // Deduplicate messages by ID to prevent duplicate webhooks
+      // @see https://github.com/devlikeapro/waha/issues/1564
+      DistinctMessages(),
       share(), // share it so we don't process twice in message.any
     );
     messagesFromOthers$ = messagesFromOthers$.pipe(
@@ -485,6 +489,10 @@ export class WhatsappSessionGoWSCore extends WhatsappSession {
         return msg;
       }),
       mergeMap((msg) => this.processIncomingMessage(msg, true)),
+      filter(Boolean),
+      // Deduplicate messages by ID to prevent duplicate webhooks
+      // @see https://github.com/devlikeapro/waha/issues/1564
+      DistinctMessages(),
       share(), // share it so we don't process twice in message.any
     );
     const messagesFromAll$ = merge(messagesFromMe$, messagesFromOthers$);

src/core/utils/reactive.ts

@@ -1,10 +1,50 @@
+import { parseMessageIdSerialized } from '@waha/core/utils/ids';
+import { WAMessage } from '@waha/structures/responses.dto';
 import { WAMessageAckBody } from '@waha/structures/webhooks.dto';
 import { distinct, interval } from 'rxjs';
 
 export function DistinctAck(flushEvery: number = 60_000) {
-  // only if we haven’t seen this key since the last flush
+  // only if we haven't seen this key since the last flush
   return distinct(
     (msg: WAMessageAckBody) => `${msg.id}-${msg.ack}-${msg.participant}`,
     interval(flushEvery),
   );
 }
+
+/**
+ * Extracts the unique WhatsApp message ID from a serialized WAHA message ID.
+ * Message IDs have format: {fromMe}_{chatId}_{uniqueId}[_{participant}]
+ *
+ * The uniqueId part is what WhatsApp generates and remains constant even when
+ * the same message is delivered with different chat identifiers (LID vs JID).
+ *
+ * @example
+ * "false_13649439626@lid_ABC123" => "ABC123"
+ * "false_2010XXXXXXX@c.us_ABC123" => "ABC123"
+ */
+function extractUniqueMessageId(messageId: string): string {
+  const key = parseMessageIdSerialized(messageId, true);
+  return key.id;
+}
+
+/**
+ * Deduplicates messages by their unique WhatsApp message ID.
+ * This is needed to prevent duplicate webhooks for the same message,
+ * which can happen in GOWS when receiving the first message from a new sender.
+ *
+ * When a new contact sends their first message, WhatsApp may deliver:
+ * 1. Two events with the same full ID but different internal structures
+ * 2. Two events with different chat identifiers (LID vs JID) but same unique message ID
+ *
+ * This function extracts the unique message ID part and deduplicates based on that,
+ * along with fromMe flag to avoid conflicts between sent and received messages.
+ *
+ * @see https://github.com/devlikeapro/waha/issues/1564
+ */
+export function DistinctMessages(flushEvery: number = 60_000) {
+  return distinct((msg: WAMessage) => {
+    const uniqueId = extractUniqueMessageId(msg.id);
+    // Include fromMe to distinguish sent vs received with same ID
+    return `${msg.fromMe}_${uniqueId}`;
+  }, interval(flushEvery));
+}