Implement thread list update feature

lib/main.dart

@@ -93,6 +93,20 @@ class _MyHomePageState extends State<MyHomePage> {
           // Here we take the value from the MyHomePage object that was created by
           // the App.build method, and use it to set our appbar title.
           title: Text(widget.title),
+          actions: [
+            TextButton.icon(
+                onPressed: () {
+                  ScaffoldMessenger.of(context).showSnackBar(
+                    const SnackBar(
+                        content: Text('Обновление списка тредов...')),
+                  );
+                  Provider.of<ThreadListModel>(context, listen: false).update();
+                },
+                label: const Text("Обновить"),
+                style: TextButton.styleFrom(
+                    primary: Theme.of(context).colorScheme.onPrimary),
+                icon: Icon(Icons.sync))
+          ],
         ),
         body: Center(
           child: Container(

lib/message_item_view.dart

@@ -1,18 +1,28 @@
+import 'package:enough_mail/enough_mail.dart';
 import 'package:flutter/material.dart';
 import 'package:provider/provider.dart';
 import 'package:wind/thread_model.dart';
 
 class MessageItemView extends StatelessWidget {
-  const MessageItemView({Key? key, required this.item, required this.isOpPost})
+  const MessageItemView(
+      {Key? key,
+      required this.item,
+      required this.isOpPost,
+      required this.isLast})
       : super(key: key);
 
   final MessageItem item;
   final bool isOpPost;
+  final bool isLast;
 
   @override
   Widget build(BuildContext context) {
     return Container(
-        margin: this.isOpPost ? EdgeInsets.only(bottom: 10) : EdgeInsets.all(0),
+        margin: this.isOpPost
+            ? EdgeInsets.only(bottom: 10, left: 10, right: 10, top: 16)
+            : isLast
+                ? EdgeInsets.only(left: 10, right: 10, bottom: 16)
+                : EdgeInsets.only(left: 10, right: 10),
         child: Card(
             elevation: 5,
             child: Column(
@@ -81,6 +91,8 @@ class MessageItem {
   final String date;
   final String body;
 
+  MimeMessage? originalMessage;
+
   MessageItem(
       this.id, this.number, this.subject, this.author, this.date, this.body);
 }

lib/nntp_client.dart

@@ -6,8 +6,8 @@ import 'package:tuple/tuple.dart';
 
 class NNTPClient {
   late WebSocketChannel _channel;
-  final Queue<_NNTPCommand> commandQueue = new Queue();
-  final List<String> tempBuffer = [];
+  final Queue<_NNTPCommand> _commandQueue = new Queue();
+  final List<String> _tempBuffer = [];
 
   String? currentGroup;
 
@@ -25,22 +25,22 @@ class NNTPClient {
       var respLines = resp.split("\r\n");
       if (respLines.last == "") respLines.removeLast(); // trailing empty line
 
-      if ((respLines.length > 1 || tempBuffer.isNotEmpty) &&
+      if ((respLines.length > 1 || _tempBuffer.isNotEmpty) &&
           respLines.last.codeUnits.last != ".".codeUnits.first) {
         // if it's multiline response and it doesn't contain dot in the end
         // then looks like we need to wait for next message to concatenate with current msg
-        tempBuffer.add(resp);
+        _tempBuffer.add(resp);
         return;
       }
 
-      if (tempBuffer.isNotEmpty) {
-        tempBuffer.add(resp);
-        resp = tempBuffer.join();
+      if (_tempBuffer.isNotEmpty) {
+        _tempBuffer.add(resp);
+        resp = _tempBuffer.join();
         respLines = resp.split("\r\n");
         respLines.removeLast(); // trailing empty line
-        tempBuffer.clear();
+        _tempBuffer.clear();
       }
-      var command = commandQueue.removeFirst();
+      var command = _commandQueue.removeFirst();
       var respCode = int.parse(respLines[0].split(" ")[0]);
       command.responseCompleter.complete(_CommandResponse(respCode, respLines));
     });
@@ -49,7 +49,7 @@ class NNTPClient {
   Future<_CommandResponse> _sendCommand(
       String command, List<String> args) async {
     var cmd = _NNTPCommand(_CommandRequest(command, args));
-    commandQueue.add(cmd);
+    _commandQueue.add(cmd);
     if (args.length > 0) {
       _channel.sink.add("$command ${args.join(" ")}\r\n");
     } else {
@@ -155,6 +155,18 @@ class NNTPClient {
 
     return threads;
   }
+
+  Future<int> postArticle(MimeMessage message) async {
+    var resp = await _sendCommand("POST", []);
+    if (resp.responseCode != 340) return resp.responseCode;
+    var rawMessage = message.renderMessage() + "\r\n.\r\n";
+
+    _channel.sink.add(rawMessage);
+    var cmd = _NNTPCommand(_CommandRequest("POST", []));
+    _commandQueue.add(cmd);
+    resp = await cmd.response;
+    return resp.responseCode;
+  }
 }
 
 class _NNTPCommand {

lib/thread_list_model.dart

@@ -6,6 +6,8 @@ class ThreadListModel extends ChangeNotifier {
   String currentGroup = "";
   NNTPClient? client;
   Map<String, Map<int, List<ThreadItem>>> threads = {};
+  int _pageNum = -1;
+  List<ThreadItem> _curItems = [];
 
   Future<void> selectNewsgroup(String name) async {
     if (currentGroup == name) return;
@@ -13,27 +15,29 @@ class ThreadListModel extends ChangeNotifier {
     currentGroup = name;
     await client!.selectGroup(name);
     threads.putIfAbsent(name, () => {});
+    _curItems.clear();
+    _pageNum = -1;
 
     notifyListeners();
   }
 
-  Future<List<ThreadItem>> getNewThreads(
-      int perPage, int pageNum, bool clearCache) async {
+  Future<List<ThreadItem>> getNewThreads(bool clearCache) async {
     if (currentGroup == "") return [];
-    List<ThreadItem> items = [];
+
+    _pageNum += 1;
 
     if (clearCache) {
       threads[currentGroup]?.clear();
     }
 
-    if (threads[currentGroup]!.containsKey(pageNum)) {
-      items.addAll(threads[currentGroup]![pageNum]!);
+    if (threads[currentGroup]!.containsKey(_pageNum)) {
+      _curItems.addAll(threads[currentGroup]![_pageNum]!);
     } else {
-      var resp = await client!.getNewThreads(perPage, pageNum);
+      var resp = await client!.getNewThreads(10, _pageNum);
       resp.forEach((pair) {
         var number = pair.item1;
         var msg = pair.item2;
-        items.add(ThreadItem(
+        _curItems.add(ThreadItem(
             msg.getHeaderValue("Message-Id")!,
             number,
             msg.getHeaderValue("Subject")!,
@@ -42,9 +46,18 @@ class ThreadListModel extends ChangeNotifier {
             msg.decodeTextPlainPart()!));
       });
 
-      threads[currentGroup]![pageNum] = items;
+      if (resp.isEmpty) _pageNum -= 1;
+
+      threads[currentGroup]![_pageNum] = List.from(_curItems);
     }
 
-    return items;
+    return _curItems;
+  }
+
+  void update() {
+    _curItems.clear();
+    _pageNum = -1;
+    threads[currentGroup]!.clear();
+    notifyListeners();
   }
 }

lib/thread_list_view.dart

@@ -1,7 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:provider/provider.dart';
 import 'package:wind/thread_list_model.dart';
-import 'package:wind/thread_screen.dart';
 
 class ThreadListView extends StatefulWidget {
   @override
@@ -9,8 +8,6 @@ class ThreadListView extends StatefulWidget {
 }
 
 class ThreadListViewState extends State<ThreadListView> {
-  List<ThreadItem> _items = [];
-  int _pageNum = 0;
   String _curGroup = "";
 
   @override
@@ -24,16 +21,13 @@ class ThreadListViewState extends State<ThreadListView> {
             if (snapshot.hasData &&
                 snapshot.connectionState != ConnectionState.waiting) {
               List<ThreadItem> data = List.from(snapshot.data!);
-              _items.addAll(data);
-              if (_items.isNotEmpty &&
-                  _items.last.number != -100500 &&
-                  data.isNotEmpty)
-                _items.add(ThreadItem("", -100500, "", "", "",
+              if (data.isNotEmpty && data.last.number != -100500)
+                data.add(ThreadItem("", -100500, "", "", "",
                     "")); // magic item (for button "load more")
               return _curGroup != ""
-                  ? _threadView()
+                  ? _threadView(data)
                   : Center(
-                      child: Text("Newsgroup is not selected",
+                      child: Text("Новостная группа не выбрана",
                           style: TextStyle(
                               fontWeight: FontWeight.bold, fontSize: 16)));
             } else if (snapshot.hasError) {
@@ -46,22 +40,18 @@ class ThreadListViewState extends State<ThreadListView> {
 
   Future<List<ThreadItem>> _fetchThreadList(BuildContext context) async {
     var model = context.read<ThreadListModel>();
-    if (model.currentGroup != _curGroup) {
-      _items.clear();
-      _curGroup = model.currentGroup;
-      _pageNum = 0;
-    }
-    return await model.getNewThreads(10, _pageNum, false);
+    _curGroup = model.currentGroup;
+    return await model.getNewThreads(false);
   }
 
-  Widget _threadView() {
-    return _items.isNotEmpty
+  Widget _threadView(List<ThreadItem> items) {
+    return items.isNotEmpty
         ? Scrollbar(
             child: ListView.builder(
                 key: PageStorageKey("threadList"),
-                itemCount: _items.length,
+                itemCount: items.length,
                 itemBuilder: (context, index) {
-                  if (_items[index].number == -100500) {
+                  if (items[index].number == -100500) {
                     return Container(
                       height: 100,
                       padding: EdgeInsets.all(20),
@@ -72,19 +62,18 @@ class ThreadListViewState extends State<ThreadListView> {
                         ),
                         onPressed: () {
                           setState(() {
-                            _pageNum += 1;
-                            _items.removeLast();
+                            items.removeLast();
                           });
                         },
-                        child: Text('Load more'),
+                        child: Text('Загрузить больше'),
                       ),
                     );
                   } else
-                    return ThreadListItemView(item: _items[index]);
+                    return ThreadListItemView(item: items[index]);
                 }),
           )
         : Center(
-            child: Text("This newsgroup is empty",
+            child: Text("Эта новостная группа пуста",
                 style: TextStyle(fontWeight: FontWeight.bold, fontSize: 16)));
   }
 }

lib/thread_model.dart

@@ -1,3 +1,4 @@
+import 'package:enough_mail/enough_mail.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:wind/message_item_view.dart';
 import 'package:wind/nntp_client.dart';
@@ -9,13 +10,15 @@ class ThreadModel extends ChangeNotifier {
 
   Future<MessageItem> getPost(int number) async {
     var msg = await client!.getPost(number);
-    return MessageItem(
+    var mi = MessageItem(
         msg.getHeaderValue("Message-Id")!,
         number,
         msg.getHeaderValue("Subject")!,
         msg.getHeaderValue("From")!,
         msg.getHeaderValue("Date")!,
         msg.decodeTextPlainPart()!);
+    mi.originalMessage = msg;
+    return mi;
   }
 
   Future<List<MessageItem>> getThread(int threadNumber) async {
@@ -39,4 +42,19 @@ class ThreadModel extends ChangeNotifier {
 
     return items;
   }
+
+  Future<int> postMessage(MimeMessage opPost, String text) async {
+    var msg = MessageBuilder.buildSimpleTextMessage(
+        MailAddress.empty(), [], text,
+        subject: "Re: " + opPost.decodeSubject()!);
+    msg.setHeader("From", "anonymous");
+    msg.addHeader("In-Reply-To", opPost.getHeaderValue("Message-Id"));
+    msg.addHeader("References", opPost.getHeaderValue("Message-Id"));
+    msg.addHeader("Newsgroups", client!.currentGroup!);
+    return await client!.postArticle(msg);
+  }
+
+  void update() {
+    notifyListeners();
+  }
 }

lib/thread_screen.dart

@@ -1,7 +1,7 @@
+import 'package:enough_mail/mime_message.dart';
 import 'package:flutter/material.dart';
 import 'package:provider/provider.dart';
 import 'package:wind/message_item_view.dart';
-import 'package:wind/nntp_client.dart';
 import 'package:wind/thread_list_view.dart';
 import 'package:wind/thread_model.dart';
 
@@ -23,39 +23,54 @@ class ThreadScreen extends StatefulWidget {
 class ThreadScreenState extends State<ThreadScreen> {
   ThreadScreenState(this.threadNumber);
 
-  late NNTPClient client;
+  late ThreadModel model;
   late int threadNumber;
 
   @override
   Widget build(BuildContext context) {
-    client = context.read<NNTPClient>();
+    model = Provider.of<ThreadModel>(context, listen: false);
 
     return Scaffold(
       appBar: AppBar(
-        title: Text("Thread #${this.threadNumber}"),
+        title: Text("Тред #${this.threadNumber}"),
+        actions: [
+          TextButton.icon(
+              onPressed: () {
+                ScaffoldMessenger.of(context).showSnackBar(
+                  const SnackBar(content: Text('Обновление треда...')),
+                );
+                model.update();
+              },
+              label: const Text("Обновить"),
+              style: TextButton.styleFrom(
+                  primary: Theme.of(context).colorScheme.onPrimary),
+              icon: Icon(Icons.sync))
+        ],
       ),
       body: Center(
           child: Container(
-        width: 640,
-        child: FutureBuilder<List<MessageItem>>(
-          future: _fetch(context),
-          builder: (context, snapshot) {
-            if (snapshot.hasData) {
-              List<MessageItem> data = List.from(snapshot.data!);
-              data.insert(1, MessageItem("reply", 0, "", "", "", "")); // reply
-              return _listView(data);
-            } else if (snapshot.hasError) {
-              return Text("${snapshot.error}");
-            }
-            return Center(child: CircularProgressIndicator());
-          },
-        ),
+        width: 650,
+        child: Consumer<ThreadModel>(
+            builder: ((context, value, child) =>
+                FutureBuilder<List<MessageItem>>(
+                  future: _fetch(context),
+                  builder: (context, snapshot) {
+                    if (snapshot.hasData) {
+                      List<MessageItem> data = List.from(snapshot.data!);
+                      data.insert(
+                          1, MessageItem("reply", 0, "", "", "", "")); // reply
+                      return _listView(data);
+                    } else if (snapshot.hasError) {
+                      return Text("${snapshot.error}");
+                    }
+                    return Center(child: CircularProgressIndicator());
+                  },
+                ))),
       )),
     );
   }
 
   Future<List<MessageItem>> _fetch(BuildContext context) async {
-    var model = context.read<ThreadModel>();
     List<MessageItem> posts = [];
 
     var threadPosts = await model.getThread(threadNumber);
@@ -71,25 +86,34 @@ class ThreadScreenState extends State<ThreadScreen> {
         itemCount: data.length,
         itemBuilder: (context, index) {
           if (index == 1) {
-            return SendMessageForm();
+            return SendMessageForm(opPost: data[0].originalMessage!);
           }
-          return MessageItemView(item: data[index], isOpPost: index == 0);
+          return MessageItemView(
+              item: data[index],
+              isOpPost: index == 0,
+              isLast: index == data.length - 1);
         });
   }
 }
 
 class SendMessageForm extends StatefulWidget {
-  const SendMessageForm({Key? key}) : super(key: key);
+  const SendMessageForm({Key? key, required this.opPost}) : super(key: key);
+
+  final MimeMessage opPost;
 
   @override
   SendMessageFormState createState() {
-    return SendMessageFormState();
+    return SendMessageFormState(opPost);
   }
 }
 
 // Create a corresponding State class.
 // This class holds data related to the form.
 class SendMessageFormState extends State<SendMessageForm> {
+  SendMessageFormState(this.opPost);
+
+  final MimeMessage opPost;
+
   // Create a global key that uniquely identifies the Form widget
   // and allows validation of the form.
   //
@@ -102,50 +126,67 @@ class SendMessageFormState extends State<SendMessageForm> {
     // Build a Form widget using the _formKey created above.
     return Form(
       key: _formKey,
-      child: Column(
-        crossAxisAlignment: CrossAxisAlignment.start,
-        children: [
-          Center(
-            child: Column(children: [
-              Consumer<ThreadModel>(
-                  builder: ((context, value, child) => TextFormField(
-                        controller: value.commentTextController,
-                        minLines: 5,
-                        keyboardType: TextInputType.multiline,
-                        maxLines: null,
-                        decoration: InputDecoration(
-                            border: OutlineInputBorder(), labelText: "Comment"),
-                        // The validator receives the text that the user has entered.
-                        validator: (value) {
-                          if (value == null || value.isEmpty) {
-                            return 'Please enter some text';
-                          }
-                          return null;
-                        },
-                      ))),
-              Padding(
-                  padding: const EdgeInsets.symmetric(vertical: 16.0),
-                  child: Row(
-                      mainAxisAlignment: MainAxisAlignment.start,
-                      children: [
-                        ElevatedButton(
-                          onPressed: () {
-                            // Validate returns true if the form is valid, or false otherwise.
-                            if (_formKey.currentState!.validate()) {
-                              // If the form is valid, display a snackbar. In the real world,
-                              // you'd often call a server or save the information in a database.
-                              ScaffoldMessenger.of(context).showSnackBar(
-                                const SnackBar(
-                                    content: Text('Processing Data')),
-                              );
+      child: Container(
+        margin: EdgeInsets.only(left: 16, right: 16),
+        child: Column(
+          crossAxisAlignment: CrossAxisAlignment.start,
+          children: [
+            Center(
+              child: Column(children: [
+                Consumer<ThreadModel>(
+                    builder: ((context, value, child) => TextFormField(
+                          controller: value.commentTextController,
+                          minLines: 5,
+                          keyboardType: TextInputType.multiline,
+                          maxLines: null,
+                          decoration: InputDecoration(
+                              border: OutlineInputBorder(),
+                              labelText: "Комментарий"),
+                          // The validator receives the text that the user has entered.
+                          validator: (value) {
+                            if (value == null || value.isEmpty) {
+                              return 'Пожалуйста, введите текст';
                             }
+                            return null;
                           },
-                          child: const Text('Send'),
-                        )
-                      ]))
-            ]),
-          )
-        ],
+                        ))),
+                Consumer<ThreadModel>(
+                  builder: (((context, value, child) => Padding(
+                      padding: const EdgeInsets.symmetric(vertical: 16.0),
+                      child: Row(
+                          mainAxisAlignment: MainAxisAlignment.start,
+                          children: [
+                            ElevatedButton(
+                              onPressed: () {
+                                // Validate returns true if the form is valid, or false otherwise.
+                                if (_formKey.currentState!.validate()) {
+                                  Provider.of<ThreadModel>(context,
+                                          listen: false)
+                                      .postMessage(opPost,
+                                          value.commentTextController.text)
+                                      .then((responseCode) {
+                                    if (responseCode == 240) {
+                                      ScaffoldMessenger.of(context)
+                                          .showSnackBar(
+                                        const SnackBar(
+                                            content: Text('Пост отправлен!')),
+                                      );
+                                      Provider.of<ThreadModel>(context,
+                                              listen: false)
+                                          .update();
+                                    }
+                                  });
+                                  value.commentTextController.text = "";
+                                }
+                              },
+                              child: const Text('Отправить'),
+                            )
+                          ])))),
+                )
+              ]),
+            )
+          ],
+        ),
       ),
     );
   }