feat: redesign and lots of progress

lib/controller/bluetooth.dart

@@ -1,6 +1,8 @@
 import 'dart:async';
 
 import 'package:anyhow/anyhow.dart';
+import 'package:flutter/foundation.dart'
+    show TargetPlatform, defaultTargetPlatform;
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:flutter_reactive_ble/flutter_reactive_ble.dart'
     hide ConnectionStatus, Result, Logger;
@@ -173,9 +175,6 @@ class BluetoothController {
         (currentState.$1 == ConnectionStatus.connected ||
             currentState.$1 == ConnectionStatus.connecting)) {
       log.info('Already connected or connecting to $deviceId.');
-      if (currentState.$1 == ConnectionStatus.connected) {
-        unawaited(_requestMtuOnConnect(deviceId));
-      }
       return Ok(null);
     }
 
@@ -191,6 +190,7 @@ class BluetoothController {
     try {
       await _connectionStateSubscription?.cancel();
       _updateConnectionState(ConnectionStatus.connecting, deviceId);
+      final connectionResult = Completer<Result<void>>();
 
       _connectionStateSubscription = _ble
           .connectToDevice(
@@ -199,12 +199,21 @@ class BluetoothController {
         servicesWithCharacteristicsToDiscover:
             servicesWithCharacteristicsToDiscover,
       )
-          .listen((update) {
+          .listen((update) async {
         switch (update.connectionState) {
           case DeviceConnectionState.connected:
             _connectedDeviceId = deviceId;
             _updateConnectionState(ConnectionStatus.connected, deviceId);
-            unawaited(_requestMtuOnConnect(deviceId));
+            if (!connectionResult.isCompleted) {
+              final mtuResult = await _requestInitialMtu(deviceId);
+              if (mtuResult.isErr()) {
+                log.warning(
+                  'Initial MTU request failed for $deviceId: '
+                  '${mtuResult.unwrapErr()}',
+                );
+              }
+              connectionResult.complete(Ok(null));
+            }
             break;
           case DeviceConnectionState.connecting:
             _updateConnectionState(ConnectionStatus.connecting, deviceId);
@@ -214,14 +223,31 @@ class BluetoothController {
             break;
           case DeviceConnectionState.disconnected:
             _cleanUpConnection();
+            if (!connectionResult.isCompleted) {
+              connectionResult.complete(
+                bail('Failed to connect to $deviceId: disconnected'),
+              );
+            }
             break;
         }
       }, onError: (Object error, StackTrace st) {
         log.severe('Failed to connect to $deviceId: $error', error, st);
         _cleanUpConnection();
+        if (!connectionResult.isCompleted) {
+          connectionResult.complete(
+            bail('Failed to connect to $deviceId: $error'),
+          );
+        }
       });
 
-      return Ok(null);
+      try {
+        return await connectionResult.future.timeout(timeout);
+      } on TimeoutException {
+        await _connectionStateSubscription?.cancel();
+        _connectionStateSubscription = null;
+        _cleanUpConnection();
+        return bail('Timed out connecting to $deviceId');
+      }
     } catch (e) {
       _cleanUpConnection();
       return bail('Failed to connect to $deviceId: $e');
@@ -301,7 +327,7 @@ class BluetoothController {
       {int mtu = defaultMtu}) async {
     final result = await requestMtuAndGetValue(deviceId, mtu: mtu);
     if (result.isErr()) {
-      return bail(result.unwrapErr());
+      return Err(result.unwrapErr());
     }
     return Ok(null);
   }
@@ -310,6 +336,10 @@ class BluetoothController {
       {int mtu = defaultMtu}) async {
     try {
       final negotiatedMtu = await _ble.requestMtu(deviceId: deviceId, mtu: mtu);
+      if (negotiatedMtu <= 0) {
+        return bail(
+            'Error requesting MTU $mtu for $deviceId: negotiated invalid MTU $negotiatedMtu');
+      }
       log.info(
           'MTU negotiated for $deviceId: requested $mtu, got $negotiatedMtu');
       return Ok(negotiatedMtu);
@@ -318,12 +348,11 @@ class BluetoothController {
     }
   }
 
-  Future<void> _requestMtuOnConnect(String deviceId) async {
-    final mtuResult = await requestMtu(deviceId, mtu: defaultMtu);
-    if (mtuResult.isErr()) {
-      log.warning(
-          'MTU request after connect failed for $deviceId: ${mtuResult.unwrapErr()}');
+  Future<Result<void>> _requestInitialMtu(String deviceId) async {
+    if (defaultTargetPlatform != TargetPlatform.android) {
+      return Ok(null);
     }
+    return requestMtu(deviceId, mtu: defaultMtu);
   }
 
   Stream<List<int>> subscribeToCharacteristic(