Overseer and HttpsMessageBuilder

.idea/.idea.InstaFollowersOverseer/.idea/discord.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
   <component name="DiscordProjectSettings">
-    <option name="show" value="ASK" />
+    <option name="show" value="PROJECT_FILES" />
     <option name="description" value="" />
   </component>
 </project>

DataModels/Config.cs

@@ -6,6 +6,7 @@ public class Config : DtsodFile
     public string botToken;
     public string instagramLogin;
     public string instagramPassword;
+    public double checksIntervalMinutes;
     #nullable enable
 
     public Config(string fileNameWithoutExt) : base(fileNameWithoutExt) { }
@@ -18,9 +19,11 @@ public class Config : DtsodFile
             botToken = dtsod[nameof(botToken)];
             instagramLogin = dtsod[nameof(instagramLogin)];
             instagramPassword = dtsod[nameof(instagramPassword)];
+            checksIntervalMinutes = dtsod[nameof(checksIntervalMinutes)];
         }
         catch (Exception ex)
         {
+            LoadedSuccessfully = false;
             throw new Exception($"your {FileName} format is invalid\n"
                                 + $"See {FileExampleName}", innerException: ex);
         }
@@ -32,7 +35,8 @@ public class Config : DtsodFile
         {
             { nameof(botToken), botToken },
             { nameof(instagramLogin), instagramLogin },
-            { nameof(instagramPassword), instagramPassword }
+            { nameof(instagramPassword), instagramPassword },
+            { nameof(checksIntervalMinutes), checksIntervalMinutes }
         };
         return d;
     }

DataModels/DtsodFile.cs

@@ -4,6 +4,8 @@ namespace InstaFollowersOverseer;
 
 public abstract class DtsodFile
 {
+    public bool LoadedSuccessfully = false;
+    
     public readonly string FileNameWithoutExt;
     public readonly string FileName;
     public readonly string FileExampleName;
@@ -42,6 +44,8 @@ public abstract class DtsodFile
 
         string fileText = File.ReadAllText(FileName);
         Program.MainLogger.LogDebug(fileText);
+        // should be set to false on LoadFromFile() errors
+        LoadedSuccessfully = true;
         return new DtsodV23(fileText);
     }
 
@@ -51,11 +55,14 @@ public abstract class DtsodFile
     
     public void SaveToFile()
     {
+        if(!LoadedSuccessfully)
+            return;
+        
+        if(File.Exists(FileName))
+            CreateBackup();
         Program.MainLogger.LogInfo($"saving file {FileName}");
         string dtsodStr = ToDtsod().ToString();
         Program.MainLogger.LogDebug(dtsodStr);
-        if(File.Exists(FileName))
-            CreateBackup();
         File.OpenWrite(FileName)
             .FluentWriteString("#DtsodV23\n")
             .FluentWriteString(dtsodStr)

DataModels/InstagramObservableParams.cs

@@ -2,18 +2,18 @@ namespace InstaFollowersOverseer;
 
 public class InstagramObservableParams
 {
-    public string instagramUserId;
+    public string instagramUsername;
     public bool notifyOnFollowing=true;
     public bool notifyOnUnfollowing=true;
 
-    public InstagramObservableParams(string instaUserId)
+    public InstagramObservableParams(string instaUsername)
     {
-        instagramUserId = instaUserId;
+        instagramUsername = instaUsername;
     }
 
     public InstagramObservableParams(DtsodV23 _overseeParams)
     {
-        instagramUserId = _overseeParams["instagramUserId"];
+        instagramUsername = _overseeParams["instagramUsername"];
         if (_overseeParams.TryGetValue("notifyOnFollowing", out var _notifyOnFollowing))
             notifyOnFollowing = _notifyOnFollowing;
         if (_overseeParams.TryGetValue("notifyOnUnfollowing", out var _notifyOnUnfollowing))
@@ -23,7 +23,7 @@ public class InstagramObservableParams
     public DtsodV23 ToDtsod()
     {
         var d = new DtsodV23();
-        d.Add(nameof(instagramUserId), instagramUserId);
+        d.Add(nameof(instagramUsername), instagramUsername);
         if(!notifyOnFollowing)
             d.Add(nameof(notifyOnFollowing), false);
         if(!notifyOnUnfollowing)

DataModels/UsersData.cs

@@ -2,8 +2,8 @@ namespace InstaFollowersOverseer;
 
 public class UsersData : DtsodFile
 {
-    private Dictionary<string, List<InstagramObservableParams>> usersData=new();
+    public Dictionary<string, List<InstagramObservableParams>> UsersDict=new();
-    
+
     public UsersData(string fileName) : base(fileName) {}
     
     public override void LoadFromFile()
@@ -19,11 +19,12 @@ public class UsersData : DtsodFile
                 foreach (DtsodV23 _overseeParams in uset.Value)
                     oparams.Add(new InstagramObservableParams(_overseeParams));
 
-                usersData.Add(telegramUserId, oparams);
+                UsersDict.Add(telegramUserId, oparams);
             }
         }
         catch (Exception ex)
         {
+            LoadedSuccessfully = false;
             throw new Exception($"your {FileName} format is invalid\n"
                                 + $"See {FileExampleName}", innerException: ex);
         }
@@ -32,7 +33,7 @@ public class UsersData : DtsodFile
     public override DtsodV23 ToDtsod()
     {
         var b = new DtsodV23();
-        foreach (var userS in usersData) 
+        foreach (var userS in UsersDict) 
             b.Add(userS.Key, 
                 userS.Value.Select<InstagramObservableParams, DtsodV23>(iop =>
                     iop.ToDtsod()
@@ -40,28 +41,30 @@ public class UsersData : DtsodFile
         return b;
     }
 
-    public List<InstagramObservableParams> Get(string telegramUserId)
+    public List<InstagramObservableParams>? Get(long telegramUserId)
     {
-        if (!usersData.TryGetValue(telegramUserId, out var overseeParams))
+        string userIdStr = telegramUserId.ToString();
-            throw new Exception($"there is no settings for user {telegramUserId}");
+        if (!UsersDict.TryGetValue(userIdStr, out var overseeParams))
+            return null;
         return overseeParams;
     }
 
-    public void AddOrSet(string telegramUserId, InstagramObservableParams instagramObservableParams)
+    public void AddOrSet(long telegramUserId, InstagramObservableParams instagramObservableParams)
     {
         // Add
         // doesnt contain settings for telegramUserId
-        if (!usersData.TryGetValue(telegramUserId, out var thisUsersData))
+        string userIdStr = telegramUserId.ToString();
+        if (!UsersDict.TryGetValue(userIdStr, out var thisUsersData))
         {
-            usersData.Add(telegramUserId, new (){ instagramObservableParams });
+            UsersDict.Add(userIdStr, new (){ instagramObservableParams });
             return;
         }
 
         // Set
-        // settings for telegramUserId contain InstagramObservableParams with instagramObservableParams.instagramUserId
+        // settings for telegramUserId contain InstagramObservableParams with instagramObservableParams.instagramUsername
         for (var i = 0; i < thisUsersData.Count; i++)
         {
-            if (thisUsersData[i].instagramUserId == instagramObservableParams.instagramUserId)
+            if (thisUsersData[i].instagramUsername == instagramObservableParams.instagramUsername)
             {
                 thisUsersData[i] = instagramObservableParams;
                 return;
@@ -69,11 +72,11 @@ public class UsersData : DtsodFile
         }
         
         // Add
-        // doesnt contain InstagramObservableParams with instagramObservableParams.instagramUserId
+        // doesnt contain InstagramObservableParams with instagramObservableParams.instagramUsername
         thisUsersData.Add(instagramObservableParams);
     }
 
-    public void AddOrSet(string telegramUserId, IEnumerable<InstagramObservableParams> instagramObservableParams)
+    public void AddOrSet(long telegramUserId, IEnumerable<InstagramObservableParams> instagramObservableParams)
     {
         foreach (var p in instagramObservableParams) 
             AddOrSet(telegramUserId, p);

InstaFollowersOverseer.csproj

@@ -19,6 +19,8 @@
     <!--third-party dependencies-->
     <ItemGroup>
       <PackageReference Include="InstaSharper" Version="1.4.82" />
+      <PackageReference Include="MarkdownDeep.NET.Core" Version="1.5.0.4" />
+      <PackageReference Include="MarkedNet" Version="2.1.4" />
       <PackageReference Include="Telegram.Bot" Version="18.0.0" />
       <!--PackageReference Include="Telegram.Bots.Extensions.Polling" Version="5.9.0" /-->
     </ItemGroup>

InstaFollowersOverseer.csproj.DotSettings

@@ -0,0 +1,4 @@
+<wpf:ResourceDictionary xml:space="preserve" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:ss="urn:shemas-jetbrains-com:settings-storage-xaml" xmlns:wpf="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
+	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=datamodels/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=instagram/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/CodeInspection/NamespaceProvider/NamespaceFoldersToSkip/=telegram/@EntryIndexedValue">True</s:Boolean></wpf:ResourceDictionary>

InstaFollowersOverseer.sln.DotSettings.user

@@ -1,3 +1,8 @@
 <wpf:ResourceDictionary xml:space="preserve" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:ss="urn:shemas-jetbrains-com:settings-storage-xaml" xmlns:wpf="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
 	<s:String x:Key="/Default/CodeInspection/Highlighting/SweaWarningsMode/@EntryValue">ShowAndRun</s:String>
+	<s:String x:Key="/Default/Environment/AssemblyExplorer/XmlDocument/@EntryValue">&lt;AssemblyExplorer&gt;&#xD;
+  &lt;Assembly Path="C:\Users\User\.nuget\packages\telegram.bot\18.0.0\lib\netcoreapp3.1\Telegram.Bot.dll" /&gt;&#xD;
+  &lt;Assembly Path="C:\Users\User\.nuget\packages\markdowndeep.net.core\1.5.0.4\lib\netcoreapp2.0\MarkdownDeep.Core.dll" /&gt;&#xD;
+  &lt;Assembly Path="C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\7.0.2\ref\net7.0\System.Collections.NonGeneric.dll" /&gt;&#xD;
+&lt;/AssemblyExplorer&gt;</s:String>
 </wpf:ResourceDictionary>

Instagram/FollowersDiff.cs

@@ -0,0 +1,45 @@
+using DTLib.Ben.Demystifier.Enumerable;
+
+namespace InstaFollowersOverseer.Instagram;
+
+public readonly record struct FollowersDiff(IList<string> Unfollowed, IList<string> Followed)
+{
+    public static readonly FollowersDiff Empty =
+        new FollowersDiff(EnumerableIList<string>.Empty, EnumerableIList<string>.Empty);
+
+    public bool IsEmpty() => Followed.Count + Unfollowed.Count == 0;
+    
+    /// <summary>
+    /// generates message aouut followed and unfollowed users
+    /// </summary>
+    /// <param name="b">string builder to append the message to</param>
+    /// <param name="ct">diff computation happens in this method because it enumerates yield returned enumerables</param>
+    public void AppendDiffMessageTo(HtmlMessageBuilder b, CancellationToken ct)
+    {
+        if (Followed.Count != 0)
+        {
+            b.BeginStyle(TextStyle.Italic).Text(Followed.Count).Text(" users followed:\n").EndStyle();
+            foreach (var u in Followed)
+            {
+                if (ct.IsCancellationRequested)
+                    return;
+                // username with clickable link
+                b.SetUrl("https://www.instagram.com/" + u).BeginStyle(TextStyle.Link).Text(u).EndStyle()
+                    .Text('\n');
+            }
+        }
+
+        if (Unfollowed.Count != 0)
+        {
+            b.BeginStyle(TextStyle.Italic).Text(Unfollowed.Count).Text(" users unfollowed:\n").EndStyle();
+            foreach (var u in Followed)
+            {
+                if (ct.IsCancellationRequested)
+                    return;
+                // username with clickable link
+                b.SetUrl("https://www.instagram.com/" + u).BeginStyle(TextStyle.Link).Text(u).EndStyle()
+                    .Text('\n');
+            }
+        }
+    }
+}

Instagram/InstagramWrapper.cs

@@ -10,7 +10,7 @@ public static class InstagramWrapper
     public static ContextLogger InstagramLogger = new("instagram",ParentLogger);
     private static IInstaApi Api=null!;
     
-    public static async void Init()
+    public static async Task InitAsync()
     {
         try
         {
@@ -27,13 +27,13 @@ public static class InstagramWrapper
                     UserName = CurrentConfig.instagramLogin,
                     Password = CurrentConfig.instagramPassword
                 })
-                .SetRequestDelay(RequestDelay.FromSeconds(0, 1))
+                .SetRequestDelay(RequestDelay.FromSeconds(5, 10))
                 .Build();
             InstagramLogger.LogInfo("instagram login starting");
             var rezult= await Api.LoginAsync();
             if (!rezult.Succeeded)
                 throw new Exception("login exception:\n" + rezult.Info + '\n' + rezult.Value);
-            InstagramLogger.LogInfo("instagram wrapper have initialized and connected successfully");
+            InstagramLogger.LogInfo("instagram wrapper initialized and connected successfully");
         }
         catch (OperationCanceledException) {}
         catch (Exception ex)
@@ -43,7 +43,7 @@ public static class InstagramWrapper
         }
     }
 
-    public static async Task<InstaUser?> GetUserAsync(string usernameOrUrl)
+    public static async Task<InstaUser?> TryGetUserAsync(string usernameOrUrl)
     {
         // url
         if (usernameOrUrl.Contains('/'))
@@ -55,4 +55,26 @@ public static class InstagramWrapper
         var u=await Api.GetUserAsync(usernameOrUrl);
         return u.Succeeded ? u.Value : null;
     }
+
+    private static Dictionary<string, IEnumerable<string>> FollowersDict=new();
+
+    /// may took long time if user have many followers
+    public static async Task<FollowersDiff> GetFollowersDiffAsync(string instaUser)
+    {
+        if (await TryGetUserAsync(instaUser) is null)
+            throw new Exception($"instagram user {instaUser} doesnt exist");
+        var maybeFollowers = await Api.GetUserFollowersAsync(instaUser, PaginationParameters.Empty);
+        if (!maybeFollowers.Succeeded)
+            throw new Exception($"can't get followers of user {instaUser}");
+        var currentFollowers = maybeFollowers.Value.Select(f=>f.UserName).ToList();
+        if(!FollowersDict.TryGetValue(instaUser, out var _prevFollowers))
+        {
+            FollowersDict.Add(instaUser, currentFollowers);
+            return FollowersDiff.Empty;
+        }
+        var prevFollowers = _prevFollowers.ToList();
+        var unfollowed = prevFollowers.Except(currentFollowers).ToList();
+        var followed = currentFollowers.Except(prevFollowers).ToList();
+        return new FollowersDiff(unfollowed, followed);
+    }
 }

Program.cs

@@ -1,7 +1,9 @@
 global using System;
-global using System.Threading.Tasks;
-global using System.Linq;
 global using System.Collections.Generic;
+global using System.Linq;
+global using System.Text;
+global using System.Threading;
+global using System.Threading.Tasks;
 global using DTLib;
 global using DTLib.Filesystem;
 global using DTLib.Extensions;
@@ -11,8 +13,6 @@ global using File = DTLib.Filesystem.File;
 global using Directory = DTLib.Filesystem.Directory;
 global using Path = DTLib.Filesystem.Path;
 global using static InstaFollowersOverseer.SharedData;
-using System.Text;
-using System.Threading;
 
 namespace InstaFollowersOverseer;
 
@@ -40,15 +40,21 @@ static class Program
             {
                 Stop();
                 Thread.Sleep(1000);
-                MainLogger.LogInfo("all have cancelled");
+                Overseer.Stop();
                 e.Cancel = false;
             };
 
-            Instagram.InstagramWrapper.Init();
+            Task[] tasks={
-            Telegram.TelegramWrapper.Init();
+                Instagram.InstagramWrapper.InitAsync(),
+                TelegramWrapper.InitAsync()
+            };
+            Task.WaitAll(tasks);
+            
+            Overseer.Start();
 
             Task.Delay(-1, MainCancel.Token).GetAwaiter().GetResult();
             Thread.Sleep(1000);
+            MainLogger.LogInfo("all have cancelled");
         }
         catch (OperationCanceledException) {}
         catch (Exception ex)

Telegram/HtmlMessageBuilder.cs

@@ -0,0 +1,182 @@
+
+using System.Net.Mime;
+using Microsoft.Extensions.Primitives;
+
+namespace InstaFollowersOverseer;
+
+/// <summary>
+/// Class that builds selegram message with html tags.
+/// It is a state machine.
+/// Exapmple:
+///  SetUrl("https://x.com").BeginStyle(TextStyle.Url).Text("X").EndStyle()
+///  opens html a tag with href=https://x.com and content X, then closes tag
+/// </summary>
+// supported tags:
+// <b>bold</b>
+// <i>italic</i> 
+// <s>crossed</s>
+// <u>underline</u>
+// <tg-spoiler>spoiler</tg-spoiler>
+// <a href="http://www.example.com/">inline URL</a>
+// <a href="tg://user?id=123456789">inline mention of a user</a>
+// <code>inlne code</code>
+// <pre language="c++">code block</pre>
+public class HtmlMessageBuilder
+{
+    record struct BuilderState(TextStyle Style, string? Url = null, long? UserId = null, string? CodeLang = null)
+    {
+        public void Reset()
+        {
+            Style = TextStyle.PlainText;
+            Url = null;
+            UserId = null;
+            CodeLang = null;
+        }
+    }
+
+    private BuilderState _state=new(TextStyle.PlainText);
+    StringBuilder _plainText=new();
+    StringBuilder _html=new();
+
+    protected void ReplaceHtmlReservedChar(char c) =>
+        _html.Append(c switch
+        {
+            '<'=>"&lt",
+            '>'=>"&gt",
+            '&'=>"&apm",
+            '"'=>"&quot",
+            '\''=>"&apos",
+            _ => c
+        });
+    
+    protected void ReplaceHtmlReservedChars(ReadOnlySpan<char> text)
+    {
+        for (int i = 0; i < text.Length; i++) 
+            ReplaceHtmlReservedChar(text[i]);
+    }
+
+    /// opens html tags enabled in state fields
+    protected void OpenTags()
+    {
+        if(_state.Style==TextStyle.PlainText)
+            return;
+        
+        // the order of fields is very importang, it must be in reversed in CloseTags()
+        if (0!=(_state.Style & TextStyle.Bold))  _html.Append("<b>");
+        if (0!=(_state.Style & TextStyle.Italic)) _html.Append("<i>");
+        if (0!=(_state.Style & TextStyle.Crossed))  _html.Append("<s>");
+        if (0!=(_state.Style & TextStyle.Underline)) _html.Append("<u>");
+        if (0!=(_state.Style & TextStyle.Spoiler)) _html.Append("<tg-spoiler>");
+        if (0!=(_state.Style & TextStyle.Link))
+        {
+            _html.Append("<a href='");
+            if (_state.UserId is not null)
+                _html.Append("tg://user?id=").Append(_state.UserId);
+            else if (!_state.Url.IsNullOrEmpty()) 
+                _html.Append(_state.Url);
+            else throw new Exception("empty url");
+            _html.Append("'>");
+        }
+        if (0!=(_state.Style & TextStyle.CodeLine)) _html.Append("<code>");
+        if (0!=(_state.Style & TextStyle.CodeBlock)) 
+        { 
+            _html.Append("<pre");
+            if (!_state.CodeLang.IsNullOrEmpty())
+                _html.Append(" language='").Append(_state.CodeLang).Append('\'');
+            _html.Append('>');
+        }
+    }
+
+    /// closes opened html tags 
+    protected void CloseTags()
+    {
+        if(_state.Style==TextStyle.PlainText)
+            return;
+        
+        // the order of fields is very importang, it must be in reversed in CloseTags()
+        if (0!=(_state.Style & TextStyle.CodeBlock)) _html.Append("</pre>");
+        if (0!=(_state.Style & TextStyle.CodeLine))  _html.Append("</code>");
+        if (0!=(_state.Style & TextStyle.Link))      _html.Append("</a>");
+        if (0!=(_state.Style & TextStyle.Spoiler))   _html.Append("</tg-spoiler>");
+        if (0!=(_state.Style & TextStyle.Underline)) _html.Append("</u>");
+        if (0!=(_state.Style & TextStyle.Crossed))   _html.Append("</s>");
+        if (0!=(_state.Style & TextStyle.Italic))    _html.Append("</i>");
+        if (0!=(_state.Style & TextStyle.Bold))      _html.Append("</b>");
+        _state.Reset();
+    }
+
+    /// appends text to builder
+    public HtmlMessageBuilder Text(string text)
+    {
+        _plainText.Append(text);
+        ReplaceHtmlReservedChars(text);
+        return this;
+    }
+    public HtmlMessageBuilder Text(char ch)
+    {
+        _plainText.Append(ch);
+        ReplaceHtmlReservedChar(ch);
+        return this;
+    }
+    public HtmlMessageBuilder Text(int o)
+    {
+        string text = o.ToString();
+        _plainText.Append(text);
+        ReplaceHtmlReservedChars(text);
+        return this;
+    }
+    public HtmlMessageBuilder Text(long o)
+    {
+        string text = o.ToString();
+        _plainText.Append(text);
+        ReplaceHtmlReservedChars(text);
+        return this;
+    }
+    public HtmlMessageBuilder Text(object o)
+    {
+        if (o is null)
+            throw new NullReferenceException("object is null");
+        string text = o.ToString()!;
+        _plainText.Append(text);
+        ReplaceHtmlReservedChars(text);
+        return this;
+    }
+    
+    /// enables specified styles
+    public HtmlMessageBuilder BeginStyle(TextStyle style)
+    {
+        if (_state.Style != TextStyle.PlainText)
+            throw new Exception("can't begin new style before ending previous");
+        _state.Style = style;
+        OpenTags();
+        return this;
+    }
+
+    /// removes all styles
+    public HtmlMessageBuilder EndStyle()
+    {
+        CloseTags();
+        return this;
+    }
+    
+    // use before BeginStyle
+    public HtmlMessageBuilder SetUrl(string url) { _state.Url = url; return this; }
+    public HtmlMessageBuilder SetUserMention(long id) { _state.UserId=id ; return this; }
+    public HtmlMessageBuilder SetCodeLanguage(string codeLang="") { _state.CodeLang=codeLang ; return this; }
+    
+    public string ToPlainText() => _plainText.ToString();
+    public string ToHtml() => _html.ToString();
+    
+    #if DEBUG
+    public override string ToString() => ToHtml();
+    #else
+    public override string ToString() => ToPlainText();
+    #endif
+
+    public void Clear()
+    {
+        _plainText.Clear();
+        _html.Clear();
+        _state.Reset();
+    }
+}

Telegram/Overseer.cs

@@ -0,0 +1,81 @@
+using InstaFollowersOverseer.Instagram;
+
+namespace InstaFollowersOverseer;
+
+public static class Overseer
+{
+    private static ContextLogger ObserverLogger = new("observer",ParentLogger);
+
+    private static CancellationTokenSource OverseeCancel = new();
+
+    public static async void Start()
+    {
+        try
+        {
+            ObserverLogger.LogInfo("observer is starting");
+            while (!OverseeCancel.Token.IsCancellationRequested)
+            {
+                ObserverLogger.LogDebug("loop begins");
+                // parallel diff computation per telegram user
+                Parallel.ForEach(CurrentUsersData.UsersDict,
+                     tgUserData => 
+                {
+                    try
+                    {
+                        var instaUsers = tgUserData.Value;
+                        long chatId = tgUserData.Key.ToLong();
+                        
+                        // parallel diff computation per instagram user
+                        Parallel.For(0, instaUsers.Count, DiffInstaUser);
+                        
+                        async void DiffInstaUser(int i)
+                        {
+                            try
+                            {
+                                HtmlMessageBuilder b = new();
+                                ObserverLogger.LogInfo($"comparing followers lists of user {instaUsers[i]}");
+                                // slow operation
+                                FollowersDiff diff =
+                                    await InstagramWrapper.GetFollowersDiffAsync(instaUsers[i].instagramUsername);
+                                
+                                b.BeginStyle(TextStyle.Bold | TextStyle.Underline)
+                                    .Text(instaUsers[i].instagramUsername)
+                                    .EndStyle()
+                                    .Text('\n');
+                                diff.AppendDiffMessageTo(b, OverseeCancel.Token);
+                                ObserverLogger.LogInfo($"sending notification to {tgUserData.Key}");
+                                await TelegramWrapper.SendInfo(chatId, b);
+                            }
+                            catch(OperationCanceledException){}
+                            catch (Exception ex)
+                            {
+                                ObserverLogger.LogWarn("ObserveLoop", ex);
+                            }
+                        }
+
+                    }
+                    catch (OperationCanceledException) {}
+                    catch (Exception ex)
+                    {
+                        ObserverLogger.LogWarn("ObserveLoop", ex);
+                    }
+                });
+
+                ObserverLogger.LogDebug("loop ends");
+                await Task.Delay(TimeSpan.FromMinutes(CurrentConfig.checksIntervalMinutes));
+            }
+        }
+        catch (OperationCanceledException) {}
+        catch (Exception ex)
+        {
+            ObserverLogger.LogError("ObserveLoop", ex);
+        }
+    }
+
+    public static void Stop()
+    {
+        ObserverLogger.LogInfo("observer is stopping");
+        OverseeCancel.Cancel();
+        OverseeCancel = new CancellationTokenSource();
+    }
+}

Telegram/TelegramWrapper.cs

@@ -1,19 +1,18 @@
 using System.Net.Http;
-using System.Threading;
 using Telegram.Bot;
 using Telegram.Bot.Polling;
 using Telegram.Bot.Types;
 using Telegram.Bot.Types.Enums;
 using InstaFollowersOverseer.Instagram;
 
-namespace InstaFollowersOverseer.Telegram;
+namespace InstaFollowersOverseer;
 
 public static class TelegramWrapper
 {
     private static ContextLogger TelegramLogger = new("telegram", ParentLogger);
     private static TelegramBotClient Bot=null!;
 
-    public static async void Init()
+    public static async Task InitAsync()
     {
         try
         {
@@ -35,7 +34,7 @@ public static class TelegramWrapper
             };
             TelegramLogger.LogInfo("bot starting recieving long polls");
             Bot.StartReceiving(BotApiUpdateHandler, BotApiExceptionHandler, receiverOptions, Program.MainCancelToken);
-            TelegramLogger.LogInfo("telegram wrapper have initialized successfully");
+            TelegramLogger.LogInfo("telegram wrapper initialized successfully");
         }
         catch (OperationCanceledException) {}
         catch (Exception ex)
@@ -50,20 +49,34 @@ public static class TelegramWrapper
         TelegramLogger.LogError(ex);
         return Task.CompletedTask;
     }
-
+    
-    static async Task SendInfoReply(string text, Message replyToMessage)
+    /// parses text from markdown to html and sends to telegram chat
+    public static async Task SendMessage(ChatId chatId, HtmlMessageBuilder message, int? replyToMesId=null)
     {
-        TelegramLogger.LogInfo(text);
+        string html = message.ToHtml();
-        await Bot.SendTextMessageAsync(replyToMessage.Chat, text, 
+        await Bot.SendTextMessageAsync(chatId, html,
-            replyToMessageId: replyToMessage.MessageId, 
+            replyToMessageId: replyToMesId,
-            parseMode:ParseMode.MarkdownV2);
+            parseMode: ParseMode.Html);
+        message.Clear();
     }
-    static async Task SendErrorReply(string text, Message replyToMessage)
+
+    public static async Task SendInfo(ChatId chatId, HtmlMessageBuilder message, int? replyToMesId=null)
     {
-        TelegramLogger.LogWarn(text);
+        TelegramLogger.LogInfo(message);
-        await Bot.SendTextMessageAsync(replyToMessage.Chat, "error: "+text, 
+        await SendMessage(chatId, message, replyToMesId);
-            replyToMessageId: replyToMessage.MessageId, 
+    }
-            parseMode:ParseMode.MarkdownV2);
+    
+    public static async Task SendError(ChatId chatId, HtmlMessageBuilder message, int? replyToMesId=null)
+    {
+        TelegramLogger.LogWarn(message);
+        await SendMessage(chatId, new HtmlMessageBuilder().BeginStyle(TextStyle.Bold | TextStyle.Italic)
+            .Text("error: ").EndStyle().Text(message), replyToMesId);
+    }
+    public static async Task SendError(ChatId chatId, Exception ex, int? replyToMesId=null)
+    {
+        TelegramLogger.LogWarn(ex);
+        await SendMessage(chatId, new HtmlMessageBuilder().BeginStyle(TextStyle.Bold | TextStyle.Italic)
+            .Text("error: ").EndStyle().Text(ex.Message), replyToMesId);
     }
     
     private static async Task BotApiUpdateHandler(ITelegramBotClient bot, Update update, CancellationToken cls)
@@ -107,28 +120,66 @@ public static class TelegramWrapper
 
     private static async Task ExecCommandAsync(string command, string[] args, Message message)
     {
-        switch (command)
+        try
         {
-            case "start":
+            HtmlMessageBuilder rb = new();
-                await Bot.SendTextMessageAsync(message.Chat, "hi");
+            long senderId = message.From?.Id ?? message.Chat.Id;
-                break;
+            string senderName = message.From?.FirstName ?? message.Chat.FirstName ??
-            case "oversee":
+                message.Chat.Username ?? "UnknownUser";
+            switch (command)
             {
-                string usernameOrUrl = args[0];
+                case "start":
-                await SendInfoReply($"searching for instagram user <{usernameOrUrl}>", message);
+                    await SendInfo(message.Chat, rb.Text("bot started"));
-                var user = await InstagramWrapper.GetUserAsync(usernameOrUrl);
+                    break;
-                if (user is null)
+                case "oversee":
                 {
-                    await SendErrorReply($"user **{usernameOrUrl}** doesnt exist", message);
+                    string usernameOrUrl = args[0];
-                    return;
+                    await SendInfo(message.Chat, rb.Text("searching for instagram user"), message.MessageId);
+                    var user = await InstagramWrapper.TryGetUserAsync(usernameOrUrl);
+                    if (user is null)
+                    {
+                        await SendError(message.Chat, rb.Text("user ").Text(usernameOrUrl).Text(" not found"));
+                        return;
+                    }
+                    await SendInfo(message.Chat, rb.Text("user ").Text(usernameOrUrl).Text(" found"));
+                    // user id or chat id
+                    CurrentUsersData.AddOrSet(senderId, new InstagramObservableParams(usernameOrUrl));
+                    CurrentUsersData.SaveToFile();
+                    break;
                 }
-                CurrentUsersData.AddOrSet(message.Chat.Id.ToString(), new InstagramObservableParams(usernameOrUrl));
+                case "list":
-                CurrentUsersData.SaveToFile();
+                {
-                break;
+                    var userData = CurrentUsersData.Get(senderId);
+                    if (userData is null)
+                    {
+                        await SendError(message.Chat, rb.Text("no data for user"), message.MessageId);
+                        return;
+                    }
+
+                    rb.Text(userData.Count).Text("instagram users:\n");
+                    foreach (var iuParams in userData)
+                    {
+                        rb.BeginStyle(TextStyle.Bold).Text(iuParams.instagramUsername).EndStyle().Text(" - ");
+                        var iu = await InstagramWrapper.TryGetUserAsync(iuParams.instagramUsername);
+                        rb.Text(iu is null ? "user no longer exists" : iu.FullName);
+                        rb.SetUrl("https://www.instagram.com/"+iuParams.instagramUsername)
+                            .BeginStyle(TextStyle.Link)
+                            .Text(iuParams.instagramUsername)
+                            .EndStyle().Text('\n');
+                    }
+
+                    await SendInfo(message.Chat, rb, message.MessageId);
+                    break;
+                }
+                default:
+                    await SendError(message.Chat, rb.Text("ivalid command"), message.MessageId);
+                    break;
             }
-            default:
+        }
-                await SendErrorReply("ivalid command", message);
+        catch(OperationCanceledException){}
-                break;
+        catch (Exception ex)
+        {
+            await SendError(message.Chat, ex);
         }
     }
 }

Telegram/TextStyle.cs

@@ -0,0 +1,9 @@
+namespace InstaFollowersOverseer;
+
+[Flags]
+public enum TextStyle
+{
+    PlainText=0,
+    Bold=1, Italic=2, Crossed=4, Underline=8,
+    Spoiler=16, Link=32, CodeLine=64, CodeBlock=128
+}

resources/config-example.dtsod

@@ -2,3 +2,4 @@
 botToken:"19815858:aAjfawIAHAWw4_kAkg321";
 instagramLogin:"aboba";
 instagramPassword:"01234567";
+checksIntervalMinutes: 1.0;