try a queue approach

MareSynchronosServer/MareSynchronosServer/Discord/DiscordBot.cs

@@ -30,8 +30,9 @@ namespace MareSynchronosServer.Discord
         DiscordSocketClient discordClient;
         ConcurrentDictionary<ulong, string> DiscordLodestoneMapping = new();
         private Timer _timer;
+        private Timer _queueTimer;
         private readonly string[] LodestoneServers = new[] { "eu", "na", "jp", "fr", "de" };
-        private DateTime lastVerifyCall = DateTime.Now;
+        private ConcurrentQueue<(Func<Task<Embed>>, SocketUser)> verificationQueue;
         public DiscordBot(IServiceProvider services, IConfiguration configuration, ILogger<DiscordBot> logger)
         {
             this.services = services;
@@ -52,12 +53,6 @@ namespace MareSynchronosServer.Discord
         {
             if (arg.Data.Name == "register")
             {
-                if (DiscordLodestoneMapping.Count > 10)
-                {
-                    await arg.RespondAsync("The bot registrations are currently overloaded. Please wait a few minutes and try again.", ephemeral: true);
-                    return;
-                }
-
                 if (arg.Data.Options.FirstOrDefault(f => f.Name == "overwrite_old_account") != null)
                 {
                     await DeletePreviousUserAccount(arg.User.Id);
@@ -71,15 +66,17 @@ namespace MareSynchronosServer.Discord
             }
             else if (arg.Data.Name == "verify")
             {
-                if (lastVerifyCall > DateTime.Now.Subtract(TimeSpan.FromSeconds(5)))
+                EmbedBuilder eb = new EmbedBuilder();
+                if (!DiscordLodestoneMapping.ContainsKey(arg.User.Id))
                 {
-                    await arg.RespondAsync("The verification is a rate limited process. Under heavy load it might take a while until you get your turn. Please wait a few seconds and try again.");
+                    eb.WithTitle("Cannot verify registration");
+                    eb.WithDescription("You need to **/register** first before you can **/verify**");
+                    await arg.RespondAsync(embeds: new[] { eb.Build() }, ephemeral: true);
                 }
                 else
                 {
-                    lastVerifyCall = DateTime.Now;
+                    await arg.RespondAsync("The verification is a rate limited process. Under heavy load it might take a while until you get your secret key reply. The bot will get back to you as soon as it can.", ephemeral: true);
-                    Embed response = await HandleVerifyAsync(arg.User.Id);
+                    verificationQueue.Enqueue((async () => await HandleVerifyAsync(arg.User.Id), arg.User));
-                    await arg.RespondAsync(embeds: new[] { response }, ephemeral: true);
                 }
             }
             else
@@ -115,13 +112,7 @@ namespace MareSynchronosServer.Discord
         private async Task<Embed> HandleVerifyAsync(ulong id)
         {
             var embedBuilder = new EmbedBuilder();
-            if (!DiscordLodestoneMapping.ContainsKey(id))
+
-            {
-                embedBuilder.WithTitle("Cannot verify registration");
-                embedBuilder.WithDescription("You need to **/register** first before you can **/verify**");
-            }
-            else
-            {
             using var scope = services.CreateScope();
             var req = new HttpClient();
             using var db = scope.ServiceProvider.GetService<MareDbContext>();
@@ -131,11 +122,7 @@ namespace MareSynchronosServer.Discord
             {
                 Random rand = new();
                 var randomServer = LodestoneServers[rand.Next(LodestoneServers.Length)];
-                    CancellationTokenSource cts = new CancellationTokenSource();
+                var response = await req.GetAsync($"https://{randomServer}.finalfantasyxiv.com/lodestone/character/{DiscordLodestoneMapping[id]}");
-                    cts.CancelAfter(TimeSpan.FromSeconds(2));
-                    try
-                    {
-                        var response = await req.GetAsync($"https://{randomServer}.finalfantasyxiv.com/lodestone/character/{DiscordLodestoneMapping[id]}", cts.Token);
                 if (response.IsSuccessStatusCode)
                 {
                     var content = await response.Content.ReadAsStringAsync();
@@ -201,15 +188,9 @@ namespace MareSynchronosServer.Discord
                     {
                         embedBuilder.WithTitle("Failed to verify your character");
                         embedBuilder.WithDescription("Did not find requested authentication key on your profile. Make sure you have saved *twice*, then do **/verify** again.");
-                            }
-                        }
-                    }
-                    catch
-                    {
-                        embedBuilder.WithTitle("Failed to get response from Lodestone");
-                        embedBuilder.WithDescription("Wait a few seconds and try again.");
                         lodestoneAuth.StartedAt = DateTime.UtcNow;
                     }
+                }
 
                 await db.SaveChangesAsync();
             }
@@ -219,7 +200,6 @@ namespace MareSynchronosServer.Discord
                 embedBuilder.WithDescription("Start again with **/register**");
                 DiscordLodestoneMapping.TryRemove(id, out _);
             }
-            }
 
             return embedBuilder.Build();
         }
@@ -360,6 +340,7 @@ namespace MareSynchronosServer.Discord
                 discordClient.Disconnected += DiscordClient_Disconnected;
 
                 _timer = new Timer(UpdateStatus, null, TimeSpan.Zero, TimeSpan.FromSeconds(15));
+                _queueTimer = new Timer(ProcessQueue, null, TimeSpan.Zero, TimeSpan.FromSeconds(5));
             }
         }
 
@@ -371,6 +352,22 @@ namespace MareSynchronosServer.Discord
             await discordClient.StartAsync();
         }
 
+        private void ProcessQueue(object state)
+        {
+            if (verificationQueue.TryDequeue(out var queueitem))
+            {
+                var runningTask = queueitem.Item1.Invoke();
+                while (!runningTask.IsCompleted)
+                {
+                    Thread.Sleep(250);
+                }
+
+                var dataEmbed = runningTask.Result;
+                queueitem.Item2.SendMessageAsync(embed: dataEmbed);
+                logger.LogInformation("Sent login information to user");
+            }
+        }
+
         private void UpdateStatus(object state)
         {
             using var scope = services.CreateScope();
@@ -384,6 +381,7 @@ namespace MareSynchronosServer.Discord
         public async Task StopAsync(CancellationToken cancellationToken)
         {
             _timer?.Change(Timeout.Infinite, 0);
+            _queueTimer?.Change(Timeout.Infinite, 0);
 
             await discordClient.LogoutAsync();
             await discordClient.StopAsync();