add main components

lib/src/stream_channel.dart

@@ -0,0 +1,99 @@
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+import 'package:rxdart/rxdart.dart';
+import 'package:stream_chat/stream_chat.dart';
+
+class StreamChannel extends InheritedWidget {
+  final ChannelClient channelClient;
+
+  ChannelState get channelState => channelClient.state.channelState;
+  Stream<ChannelState> get channelStateStream =>
+      channelClient.state.channelStateStream;
+
+  StreamChannel({
+    Key key,
+    @required Widget child,
+    @required this.channelClient,
+  }) : super(
+          key: key,
+          child: child,
+        );
+
+  final BehaviorSubject<bool> _queryMessageController = BehaviorSubject();
+
+  Stream<bool> get queryMessage => _queryMessageController.stream;
+
+  void queryMessages() {
+    _queryMessageController.add(true);
+
+    String firstId;
+    if (channelState.messages.isNotEmpty) {
+      firstId = channelState.messages.first.id;
+    }
+
+    channelClient
+        .query(
+      messagesPagination: PaginationParams(
+        lessThan: firstId,
+        limit: 100,
+      ),
+    )
+        .then((res) {
+      _queryMessageController.add(false);
+    }).catchError((e, stack) {
+      _queryMessageController.addError(e, stack);
+    });
+  }
+
+  Future<void> getReplies(String parentId) async {
+    _queryMessageController.add(true);
+
+    String firstId;
+    if (channelClient.state.threads.containsKey(parentId)) {
+      firstId = channelClient.state.threads[parentId].first.id;
+    }
+
+    return channelClient
+        .getReplies(
+      parentId,
+      PaginationParams(
+        lessThan: firstId,
+        limit: 100,
+      ),
+    )
+        .then((res) {
+      _queryMessageController.add(false);
+    }).catchError((e, stack) {
+      _queryMessageController.addError(e, stack);
+    });
+  }
+
+  void dispose() {
+    _queryMessageController.close();
+    channelClient.dispose();
+  }
+
+  @override
+  bool updateShouldNotify(InheritedWidget oldWidget) {
+    return true;
+  }
+
+  static StreamChannel of(BuildContext context, [bool listen = false]) {
+    StreamChannel streamChannel;
+
+    if (listen) {
+      streamChannel =
+          context.dependOnInheritedWidgetOfExactType<StreamChannel>();
+    } else {
+      streamChannel = context.findAncestorWidgetOfExactType<StreamChannel>();
+    }
+
+    if (streamChannel == null) {
+      throw Exception(
+          'You must have a StreamChannel widget at the top of your widget tree');
+    }
+
+    return streamChannel;
+  }
+}