flowerreaction event under the hood improvements

src/NadekoBot/Modules/Gambling/Commands/CurrencyEvents.cs

@@ -11,6 +11,8 @@ using System.Text;
 using System.Threading.Tasks;
 using Discord.WebSocket;
 using NadekoBot.Services.Database;
+using System.Threading;
+using NLog;
 
 namespace NadekoBot.Modules.Gambling
 {
@@ -25,7 +27,6 @@ namespace NadekoBot.Modules.Gambling
                 SneakyGameStatus
             }
             //flower reaction event
-            public static readonly ConcurrentHashSet<ulong> _flowerReactionAwardedUsers = new ConcurrentHashSet<ulong>();
             public static readonly ConcurrentHashSet<ulong> _sneakyGameAwardedUsers = new ConcurrentHashSet<ulong>();
 
 
@@ -45,7 +46,6 @@ namespace NadekoBot.Modules.Gambling
                 var channel = (ITextChannel)Context.Channel;
                 try
                 {
-
                     switch (e)
                     {
                         case CurrencyEvent.FlowerReaction:
@@ -121,12 +121,63 @@ namespace NadekoBot.Modules.Gambling
                 return Task.Delay(0);
             }
 
-            public static async Task FlowerReactionEvent(CommandContext Context)
+            public static Task FlowerReactionEvent(CommandContext Context) =>
+                new FlowerReactionEvent().Start(Context);
+        }
+    }
+
+    public abstract class CurrencyEvent
     {
-                var msg = await Context.Channel.SendConfirmAsync("Flower reaction event started!", 
+        public abstract Task Start(CommandContext channel);
+    }
+
+    public class FlowerReactionEvent : CurrencyEvent
+    {
+        public readonly ConcurrentHashSet<ulong> _flowerReactionAwardedUsers = new ConcurrentHashSet<ulong>();
+        private readonly Logger _log;
+
+        private IUserMessage msg { get; set; } = null;
+
+        private CancellationTokenSource source { get; }
+        private CancellationToken cancelToken { get; }
+
+        public FlowerReactionEvent()
+        {
+            _log = LogManager.GetCurrentClassLogger();
+            source = new CancellationTokenSource();
+            cancelToken = source.Token;
+        }
+
+        private async Task End()
+        {
+            if(msg != null)
+                await msg.DeleteAsync().ConfigureAwait(false);
+
+            if(!source.IsCancellationRequested)
+                source.Cancel();
+
+            NadekoBot.Client.MessageDeleted -= MessageDeletedEventHandler;
+        }
+
+        private Task MessageDeletedEventHandler(ulong id, Optional<SocketMessage> _) {
+            if (msg?.Id == id)
+            {
+                _log.Warn("Stopping flower reaction event because message is deleted.");
+                Task.Run(() => End());
+            }
+
+            return Task.CompletedTask;
+        }
+
+        public override async Task Start(CommandContext context)
+        {
+            msg = await context.Channel.SendConfirmAsync("Flower reaction event started!",
                     "Add 🌸 reaction to this message to get 100" + NadekoBot.BotConfig.CurrencySign,
                     footer: "This event is active for up to 24 hours.")
                                                .ConfigureAwait(false);
+
+            NadekoBot.Client.MessageDeleted += MessageDeletedEventHandler;
+
             try { await msg.AddReactionAsync("🌸").ConfigureAwait(false); }
             catch
             {
@@ -149,10 +200,20 @@ namespace NadekoBot.Modules.Gambling
                 catch { }
             }))
             {
-                    await Task.Delay(TimeSpan.FromHours(24)).ConfigureAwait(false);
+                try
-                    try { await msg.DeleteAsync().ConfigureAwait(false); } catch { }
+                {
-                    _flowerReactionAwardedUsers.Clear();
+                    await Task.Delay(TimeSpan.FromHours(24), cancelToken).ConfigureAwait(false);
                 }
+                catch (OperationCanceledException)
+                {
+                    
+                }
+                if (cancelToken.IsCancellationRequested)
+                    return;
+
+                _log.Warn("Stopping flower reaction event because it expired.");
+                await End();
+                
             }
         }
     }