From 19e02501af8752c936bc2c4426b5a1ca483134f6 Mon Sep 17 00:00:00 2001
From: Alexander Zinchuk <alx.zinchuk@gmail.com>
Date: Sun, 23 Jul 2023 10:07:41 +0200
Subject: [PATCH] [Perf] API: Batch updates into single `postMessage`

---
 src/api/gramjs/worker/provider.ts | 22 ++++++++++++++++++----
 src/api/gramjs/worker/types.ts    |  4 ++--
 src/api/gramjs/worker/worker.ts   | 23 +++++++++++++++++------
 3 files changed, 37 insertions(+), 12 deletions(-)

diff --git a/src/api/gramjs/worker/provider.ts b/src/api/gramjs/worker/provider.ts
index 0ec2ee11e..23ef43385 100644
--- a/src/api/gramjs/worker/provider.ts
+++ b/src/api/gramjs/worker/provider.ts
@@ -1,7 +1,7 @@
 import type { Api } from '../../../lib/gramjs';
 import type { ApiInitialArgs, ApiOnProgress, OnApiUpdate } from '../../types';
-import type { Methods, MethodArgs, MethodResponse } from '../methods/types';
-import type { WorkerMessageEvent, OriginRequest, ThenArg } from './types';
+import type { MethodArgs, MethodResponse, Methods } from '../methods/types';
+import type { OriginRequest, ThenArg, WorkerMessageEvent } from './types';
 import type { LocalDb } from '../localDb';
 import type { TypedBroadcastChannel } from '../../../util/multitab';
 
@@ -254,8 +254,22 @@ export function cancelApiProgressMaster(messageId: string) {
 function subscribeToWorker(onUpdate: OnApiUpdate) {
   worker?.addEventListener('message', ({ data }: WorkerMessageEvent) => {
     if (!data) return;
-    if (data.type === 'update') {
-      onUpdate(data.update);
+    if (data.type === 'updates') {
+      // eslint-disable-next-line @typescript-eslint/naming-convention
+      let DEBUG_startAt: number | undefined;
+      if (DEBUG) {
+        DEBUG_startAt = performance.now();
+      }
+
+      data.updates.forEach(onUpdate);
+
+      if (DEBUG) {
+        const duration = performance.now() - DEBUG_startAt!;
+        if (duration > 5) {
+          // eslint-disable-next-line no-console
+          console.warn(`[API] Slow updates processing: ${data.updates.length} updates in ${duration} ms`);
+        }
+      }
     } else if (data.type === 'methodResponse') {
       handleMethodResponse(data);
     } else if (data.type === 'methodCallback') {
diff --git a/src/api/gramjs/worker/types.ts b/src/api/gramjs/worker/types.ts
index cf2fbea80..8b54f0028 100644
--- a/src/api/gramjs/worker/types.ts
+++ b/src/api/gramjs/worker/types.ts
@@ -6,8 +6,8 @@ import type { DebugLevel } from '../../../util/debugConsole';
 export type ThenArg<T> = T extends Promise<infer U> ? U : T;
 
 export type WorkerMessageData = {
-  type: 'update';
-  update: ApiUpdate;
+  type: 'updates';
+  updates: ApiUpdate[];
 } | {
   type: 'methodResponse';
   messageId: string;
diff --git a/src/api/gramjs/worker/worker.ts b/src/api/gramjs/worker/worker.ts
index 1f8d3b4f8..e87abfce9 100644
--- a/src/api/gramjs/worker/worker.ts
+++ b/src/api/gramjs/worker/worker.ts
@@ -4,10 +4,11 @@ import type { ApiOnProgress, ApiUpdate } from '../../types';
 import type { OriginMessageEvent, WorkerMessageData } from './types';
 
 import { DEBUG } from '../../../config';
-import { initApi, callApi, cancelApiProgress } from '../provider';
+import { callApi, cancelApiProgress, initApi } from '../provider';
 import { log } from '../helpers';
 import type { DebugLevel } from '../../../util/debugConsole';
 import { DEBUG_LEVELS } from '../../../util/debugConsole';
+import { throttleWithTickEnd } from '../../../util/schedulers';
 
 declare const self: WorkerGlobalScope;
 
@@ -154,15 +155,25 @@ function handleErrors() {
   });
 }
 
-function onUpdate(update: ApiUpdate) {
-  sendToOrigin({
-    type: 'update',
-    update,
-  });
+let pendingUpdates: ApiUpdate[] = [];
 
+const sendUpdatesOnTickEnd = throttleWithTickEnd(() => {
+  const currentUpdates = pendingUpdates;
+  pendingUpdates = [];
+
+  sendToOrigin({
+    type: 'updates',
+    updates: currentUpdates,
+  });
+});
+
+function onUpdate(update: ApiUpdate) {
   if (DEBUG && update['@type'] !== 'updateUserStatus' && update['@type'] !== 'updateServerTimeOffset') {
     log('UPDATE', update['@type'], update);
   }
+
+  pendingUpdates.push(update);
+  sendUpdatesOnTickEnd();
 }
 
 export function sendToOrigin(data: WorkerMessageData, arrayBuffer?: ArrayBuffer) {