feat: MeshCore SAR - Flutter BLE mesh radio companion app

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/providers/channels_provider.dart

@@ -0,0 +1,110 @@
+import 'package:flutter/foundation.dart';
+import '../models/channel.dart';
+
+/// Manages channel information from the MeshCore device
+class ChannelsProvider with ChangeNotifier {
+  final Map<int, Channel> _channels = {};
+  int _selectedChannelIndex = 0; // Default to public channel
+
+  /// Get all channels
+  List<Channel> get channels => _channels.values.toList()..sort((a, b) => a.index.compareTo(b.index));
+
+  /// Get a specific channel by index
+  Channel? getChannel(int index) => _channels[index];
+
+  /// Get the currently selected channel
+  Channel? get selectedChannel => _channels[_selectedChannelIndex];
+
+  /// Get the selected channel index
+  int get selectedChannelIndex => _selectedChannelIndex;
+
+  /// Get the display name for a channel
+  String getChannelDisplayName(int index) {
+    final channel = _channels[index];
+    if (channel != null) {
+      return channel.displayName;
+    }
+    // Fallback if channel hasn't been synced yet
+    return index == 0 ? 'Public' : 'Channel $index';
+  }
+
+  /// Add or update a channel
+  void addOrUpdateChannel({
+    required int index,
+    required String name,
+    required Uint8List secret,
+    int? flags,
+  }) {
+    _channels[index] = Channel(
+      index: index,
+      name: name,
+      secret: secret,
+      flags: flags,
+    );
+    notifyListeners();
+  }
+
+  /// Add or update a channel using Channel object
+  void addOrUpdateChannelObject(Channel channel) {
+    _channels[channel.index] = channel;
+    notifyListeners();
+  }
+
+  /// Remove a channel by index
+  void removeChannel(int index) {
+    if (_channels.containsKey(index)) {
+      _channels.remove(index);
+      
+      // If the deleted channel was selected, switch to public channel
+      if (_selectedChannelIndex == index) {
+        _selectedChannelIndex = 0;
+      }
+      
+      notifyListeners();
+    }
+  }
+
+  /// Select a channel for sending messages
+  void selectChannel(int index) {
+    if (_channels.containsKey(index) || index == 0) {
+      _selectedChannelIndex = index;
+      notifyListeners();
+    }
+  }
+
+  /// Get channels by type (hash-based vs normal)
+  List<Channel> getHashChannels() {
+    return channels.where((c) => c.isHashChannel).toList();
+  }
+
+  List<Channel> getNormalChannels() {
+    return channels.where((c) => !c.isHashChannel).toList();
+  }
+
+  /// Initialize default public channel
+  void initializePublicChannel() {
+    if (!_channels.containsKey(0)) {
+      _channels[0] = Channel.publicChannel();
+      notifyListeners();
+    }
+  }
+
+  /// Clear all channels
+  void clear() {
+    _channels.clear();
+    _selectedChannelIndex = 0;
+    notifyListeners();
+  }
+
+  /// Check if channels have been loaded
+  bool get hasChannels => _channels.isNotEmpty;
+
+  /// Get the number of channels
+  int get channelCount => _channels.length;
+
+  @override
+  void dispose() {
+    _channels.clear();
+    super.dispose();
+  }
+}