Add auto-connect support (#206)

* Add autoConnect support

* Enhance autoConnect functionality for Bluetooth devices

- Added support for managing a set of auto-connect devices in both Android and iOS implementations.
- Updated connection and disconnection logic to handle auto-reconnect scenarios appropriately.
- Improved cleanup processes to prevent unwanted reconnections when devices are manually disconnected.

* Refactor connection button and add auto-reconnect toggle

- Updated the connection button layout for better UI consistency.
- Introduced an auto-reconnect toggle to manage automatic reconnections when devices become available.
- Enhanced connection and disconnection logic to respect the auto-connect setting.

* Update version to 1.2.0 and add CHANGELOG for new features

- Bumped version to 1.2.0.
- Added CHANGELOG.md detailing new features including support for `autoConnect` and UI updates for automatic reconnection.

* Improve readme

* Refactor variable naming for clarity in Bluetooth connection logic

- Changed variable name from `isAutoConnect` to `shouldAutoConnect` for better readability and understanding of its purpose in the connection state handling.

* Refactor connection handling in UniversalBlePlugin

- Simplified connection logic by always cleaning up internal state before sending connection change callbacks.
- Ensured GATT resources are only closed when autoConnect is disabled, allowing for better management of Bluetooth connections.

* Refactor disconnection handling in UniversalBlePlugin

- Introduced a new method `handlePeripheralDisconnection` to encapsulate disconnection logic, improving code readability and maintainability.
- Updated the `centralManager` methods to utilize the new disconnection handler, ensuring consistent behavior across connection state changes.

* Update darwin/Classes/UniversalBlePlugin.swift

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: Foti Dim <fotios.dimanidis@a2zebra.de>
Co-authored-by: Navideck Labs <130186950+navidecklabs@users.noreply.github.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

lib/src/extensions/ble_device_extension.dart

@@ -17,7 +17,9 @@ extension BleDeviceExtension on BleDevice {
       BleConnectionState.connected;
 
   /// Connects to the device.
-  Future<void> connect() => UniversalBle.connect(deviceId);
+  /// [autoConnect] enables automatic reconnection when the device becomes available.
+  Future<void> connect({bool autoConnect = false, Duration? timeout}) =>
+      UniversalBle.connect(deviceId, autoConnect: autoConnect, timeout: timeout);
 
   /// Disconnects from the device.
   Future<void> disconnect() => UniversalBle.disconnect(deviceId);

lib/src/universal_ble.dart

@@ -134,16 +134,26 @@ class UniversalBle {
   /// It is advised to stop scanning before connecting.
   /// It throws error if device connection fails.
   /// Default connection timeout is 60 sec.
+  ///
+  /// [autoConnect] enables automatic reconnection when the device becomes available.
+  /// Default value is `false`.
+  /// Ignored on `Windows`, `Linux` and `Web`.
+  ///
+  /// Call [disconnect] to prevent auto-reconnect even while a device is disconnected.
+  ///
   /// Can throw `ConnectionException` or `PlatformException`.
   static Future<void> connect(
     String deviceId, {
     Duration? timeout,
+    bool autoConnect = false,
   }) async {
     timeout ??= const Duration(seconds: 60);
     Completer<bool> completer =
         _connectionEventCompleter(deviceId, timeout: timeout);
 
-    _platform.connect(deviceId, connectionTimeout: timeout).catchError(
+    _platform
+        .connect(deviceId, connectionTimeout: timeout, autoConnect: autoConnect)
+        .catchError(
       (error) {
         if (completer.isCompleted) return;
         completer.completeError(ConnectionException(error));
@@ -169,15 +179,6 @@ class UniversalBle {
       UniversalLogger.logError("Get connection state failed: $e");
     }
 
-    if (connectionState == BleConnectionState.disconnected ||
-        connectionState == BleConnectionState.disconnecting) {
-      _platform.updateConnection(deviceId, false);
-      UniversalLogger.logInfo(
-        "Device $deviceId already disconnected: $connectionState",
-      );
-      return;
-    }
-
     try {
       Completer<bool> completer =
           _connectionEventCompleter(deviceId, timeout: timeout);
@@ -192,6 +193,17 @@ class UniversalBle {
         },
       );
 
+      if (connectionState == BleConnectionState.disconnected ||
+          connectionState == BleConnectionState.disconnecting) {
+        // Device was already disconnected, but we still called platform disconnect
+        // to prevent auto-reconnect. Update connection state and return.
+        _platform.updateConnection(deviceId, false);
+        UniversalLogger.logInfo(
+          "Device $deviceId already disconnected: $connectionState. Cleanup performed to prevent auto-reconnect.",
+        );
+        return;
+      }
+
       if (await completer.future.timeout(timeout)) {
         UniversalLogger.logError(
           "Device $deviceId is still connected after disconnect attempt",

lib/src/universal_ble_linux/universal_ble_linux.dart

@@ -141,7 +141,8 @@ class UniversalBleLinux extends UniversalBlePlatform {
   }
 
   @override
-  Future<void> connect(String deviceId, {Duration? connectionTimeout}) async {
+  Future<void> connect(String deviceId, {Duration? connectionTimeout, bool autoConnect = false}) async {
+    // Note: autoConnect is not directly supported on Linux platform
     final device = _findDeviceById(deviceId);
     if (device.connected) {
       updateConnection(deviceId, true);

lib/src/universal_ble_pigeon/universal_ble.g.dart

@@ -776,7 +776,7 @@ class UniversalBlePlatformChannel {
     }
   }
 
-  Future<void> connect(String deviceId) async {
+  Future<void> connect(String deviceId, {bool? autoConnect}) async {
     final pigeonVar_channelName =
         'dev.flutter.pigeon.universal_ble.UniversalBlePlatformChannel.connect$pigeonVar_messageChannelSuffix';
     final pigeonVar_channel = BasicMessageChannel<Object?>(
@@ -785,7 +785,7 @@ class UniversalBlePlatformChannel {
       binaryMessenger: pigeonVar_binaryMessenger,
     );
     final Future<Object?> pigeonVar_sendFuture =
-        pigeonVar_channel.send(<Object?>[deviceId]);
+        pigeonVar_channel.send(<Object?>[deviceId, autoConnect]);
     final pigeonVar_replyList = await pigeonVar_sendFuture as List<Object?>?;
     if (pigeonVar_replyList == null) {
       throw _createConnectionError(pigeonVar_channelName);

lib/src/universal_ble_pigeon/universal_ble_pigeon_channel.dart

@@ -69,8 +69,8 @@ class UniversalBlePigeonChannel extends UniversalBlePlatform {
   }
 
   @override
-  Future<void> connect(String deviceId, {Duration? connectionTimeout}) =>
-      _executeWithErrorHandling(() => _channel.connect(deviceId));
+  Future<void> connect(String deviceId, {Duration? connectionTimeout, bool autoConnect = false}) =>
+      _executeWithErrorHandling(() => _channel.connect(deviceId, autoConnect: autoConnect));
 
   @override
   Future<void> disconnect(String deviceId) =>

lib/src/universal_ble_platform_interface.dart

@@ -53,7 +53,7 @@ abstract class UniversalBlePlatform {
 
   Future<bool> isScanning();
 
-  Future<void> connect(String deviceId, {Duration? connectionTimeout});
+  Future<void> connect(String deviceId, {Duration? connectionTimeout, bool autoConnect = false});
 
   Future<void> disconnect(String deviceId);
 

lib/src/universal_ble_web/universal_ble_web.dart

@@ -35,7 +35,9 @@ class UniversalBleWeb extends UniversalBlePlatform {
   Future<void> connect(
     String deviceId, {
     Duration? connectionTimeout = const Duration(seconds: 10),
+    bool autoConnect = false,
   }) async {
+    // Note: autoConnect is not directly supported on Web platform
     var device = _getDeviceById(deviceId);
     if (device == null) {
       throw UniversalBleException(