Overseer and HttpsMessageBuilder

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);
+    }
 }