Sync full Android text after composition settles

lib/main.dart

@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:convert';
 
 import 'package:flutter/material.dart';
@@ -42,7 +43,8 @@ class _InputSyncPageState extends State<InputSyncPage> {
   final inputFocusNode = FocusNode();
 
   WebSocketChannel? channel;
-  String lastText = '';
+  Timer? syncDebounce;
+  String lastSyncedText = '';
   bool connected = false;
 
   @override
@@ -54,6 +56,7 @@ class _InputSyncPageState extends State<InputSyncPage> {
 
   @override
   void dispose() {
+    syncDebounce?.cancel();
     channel?.sink.close();
     hostController.dispose();
     portController.dispose();
@@ -85,10 +88,12 @@ class _InputSyncPageState extends State<InputSyncPage> {
     setState(() {
       connected = true;
     });
+    _sendCurrentText(force: true);
     inputFocusNode.requestFocus();
   }
 
   void _disconnect() {
+    syncDebounce?.cancel();
     channel?.sink.close();
     channel = null;
     setState(() {
@@ -97,23 +102,40 @@ class _InputSyncPageState extends State<InputSyncPage> {
   }
 
   void _syncTextChange() {
-    final currentText = inputController.text;
-    if (!connected || channel == null || currentText == lastText) {
-      lastText = currentText;
+    if (!connected || channel == null) {
       return;
     }
 
-    if (currentText.length > lastText.length &&
-        currentText.startsWith(lastText)) {
-      _send('insertText', text: currentText.substring(lastText.length));
-    } else if (lastText.length == currentText.length + 1 &&
-        lastText.startsWith(currentText)) {
-      _send('backspace');
-    } else {
-      _send('insertText', text: currentText);
+    final value = inputController.value;
+    if (value.composing.isValid) {
+      return;
     }
 
-    lastText = currentText;
+    final currentText = value.text;
+    if (currentText == lastSyncedText) {
+      return;
+    }
+
+    syncDebounce?.cancel();
+    syncDebounce = Timer(const Duration(milliseconds: 800), _sendCurrentText);
+  }
+
+  void _sendCurrentText({bool force = false}) {
+    if (!connected || channel == null) {
+      return;
+    }
+
+    final latestValue = inputController.value;
+    if (latestValue.composing.isValid) {
+      return;
+    }
+
+    if (!force && latestValue.text == lastSyncedText) {
+      return;
+    }
+
+    lastSyncedText = latestValue.text;
+    _send('replaceAll', text: latestValue.text);
   }
 
   void _send(String action, {String? text}) {