From 414c8bf3d6ccecd9e0ebfa3d5b2163259a9d29e0 Mon Sep 17 00:00:00 2001
From: lukasIO <mail@lukasseiler.de>
Date: Thu, 22 Aug 2024 16:22:41 +0200
Subject: [PATCH] Add firstReceivedTime and lastReceivedTime to received
 TranscriptionSegments (#1223)

* Add firstReceivedTime and lastReceivedTime to received TranscriptionSegements

* add changeset

* clear on disconnect

* set received time
---
 .changeset/spotty-years-return.md |  5 +++++
 src/room/Room.ts                  |  9 ++++++++-
 src/room/types.ts                 |  2 ++
 src/room/utils.ts                 | 10 ++++++++++
 4 files changed, 25 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/spotty-years-return.md

diff --git a/.changeset/spotty-years-return.md b/.changeset/spotty-years-return.md
new file mode 100644
index 0000000000..e2971f769f
--- /dev/null
+++ b/.changeset/spotty-years-return.md
@@ -0,0 +1,5 @@
+---
+'livekit-client': patch
+---
+
+Add firstReceivedTime and lastReceivedTime to received TranscriptionSegments
diff --git a/src/room/Room.ts b/src/room/Room.ts
index 9e2e50f49c..1ef616c640 100644
--- a/src/room/Room.ts
+++ b/src/room/Room.ts
@@ -162,6 +162,11 @@ class Room extends (EventEmitter as new () => TypedEmitter<RoomEventCallbacks>)
 
   private isResuming: boolean = false;
 
+  /**
+   * map to store first point in time when a particular transcription segment was received
+   */
+  private transcriptionReceivedTimes: Map<string, number>;
+
   /**
    * Creates a new Room, the primary construct for a LiveKit session.
    * @param options
@@ -174,6 +179,7 @@ class Room extends (EventEmitter as new () => TypedEmitter<RoomEventCallbacks>)
     this.options = { ...roomOptionDefaults, ...options };
 
     this.log = getLogger(this.options.loggerName ?? LoggerNames.Room);
+    this.transcriptionReceivedTimes = new Map();
 
     this.options.audioCaptureDefaults = {
       ...audioDefaults,
@@ -1274,6 +1280,7 @@ class Room extends (EventEmitter as new () => TypedEmitter<RoomEventCallbacks>)
     this.clearConnectionReconcile();
     this.isResuming = false;
     this.bufferedEvents = [];
+    this.transcriptionReceivedTimes.clear();
     if (this.state === ConnectionState.Disconnected) {
       return;
     }
@@ -1535,7 +1542,7 @@ class Room extends (EventEmitter as new () => TypedEmitter<RoomEventCallbacks>)
         : this.getParticipantByIdentity(transcription.transcribedParticipantIdentity);
     const publication = participant?.trackPublications.get(transcription.trackId);
 
-    const segments = extractTranscriptionSegments(transcription);
+    const segments = extractTranscriptionSegments(transcription, this.transcriptionReceivedTimes);
 
     publication?.emit(TrackEvent.TranscriptionReceived, segments);
     participant?.emit(ParticipantEvent.TranscriptionReceived, segments, publication);
diff --git a/src/room/types.ts b/src/room/types.ts
index e3f12a8417..a92127f478 100644
--- a/src/room/types.ts
+++ b/src/room/types.ts
@@ -65,4 +65,6 @@ export interface TranscriptionSegment {
   startTime: number;
   endTime: number;
   final: boolean;
+  firstReceivedTime: number;
+  lastReceivedTime: number;
 }
diff --git a/src/room/utils.ts b/src/room/utils.ts
index e16a6b769b..34037746f1 100644
--- a/src/room/utils.ts
+++ b/src/room/utils.ts
@@ -532,8 +532,16 @@ export function toHttpUrl(url: string): string {
 
 export function extractTranscriptionSegments(
   transcription: TranscriptionModel,
+  firstReceivedTimesMap: Map<string, number>,
 ): TranscriptionSegment[] {
   return transcription.segments.map(({ id, text, language, startTime, endTime, final }) => {
+    const firstReceivedTime = firstReceivedTimesMap.get(id) ?? Date.now();
+    const lastReceivedTime = Date.now();
+    if (final) {
+      firstReceivedTimesMap.delete(id);
+    } else {
+      firstReceivedTimesMap.set(id, firstReceivedTime);
+    }
     return {
       id,
       text,
@@ -541,6 +549,8 @@ export function extractTranscriptionSegments(
       endTime: Number.parseInt(endTime.toString()),
       final,
       language,
+      firstReceivedTime,
+      lastReceivedTime,
     };
   });
 }