From a4d996fb3db6d444092ecf4de962c626440d08fa Mon Sep 17 00:00:00 2001
From: Starbeamrainbowlabs <sbrl@starbeamrainbowlabs.com>
Date: Fri, 8 Feb 2019 11:30:16 +0000
Subject: [PATCH] Bugfix: Fix crash if the next reminder is deleted before it
 can be sent. Also enable some debug logging, just in case it acts up again.

---
 RhinoReminds/ClientListener.cs | 29 +++++++++++++----------------
 RhinoReminds/ReminderList.cs   |  7 +++++--
 2 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/RhinoReminds/ClientListener.cs b/RhinoReminds/ClientListener.cs
index a045d9b..6ead432 100644
--- a/RhinoReminds/ClientListener.cs
+++ b/RhinoReminds/ClientListener.cs
@@ -313,8 +313,9 @@ namespace RhinoReminds
 
 		private void interruptReminderWatcher()
 		{
-			reminderWatcherReset?.Cancel();
+			CancellationTokenSource oldToken = reminderWatcherReset;
 			reminderWatcherReset = new CancellationTokenSource();
+			oldToken?.Cancel();
 		}
 
 		private async Task watchForReminders()
@@ -324,12 +325,12 @@ namespace RhinoReminds
 
 			// ----- Events -----
 			// This will run on the firing thread, not on this thread
-			reminderList.OnReminderListUpdate += (object sender, Reminder newReminder) => {
+			reminderList.OnReminderListUpdate += (object sender, ReminderListUpdateEventArgs eventArgs) => {
 				Reminder newNextReminder = reminderList.GetNextReminder();
-				//Console.WriteLine("[Rhino/Reminderd/Canceller] Reminder added - comparing.");
-				//Console.WriteLine($"[Rhino/Reminderd/Canceller] {nextReminder} / {newNextReminder}");
+				Console.WriteLine("[Rhino/Reminderd/Canceller] Reminder added - comparing.");
+				Console.WriteLine($"[Rhino/Reminderd/Canceller] {nextReminder} / {newNextReminder}");
 				if (nextReminder != newNextReminder) {
-					//Console.WriteLine($"[Rhino/Reminderd/Canceller] Cancelling");
+					Console.WriteLine($"[Rhino/Reminderd/Canceller] Cancelling");
 					nextReminder = newNextReminder;
 					interruptReminderWatcher();
 				}
@@ -345,35 +346,34 @@ namespace RhinoReminds
 						nextWaitingTime = nextReminder.Time - DateTime.Now;
 						if (DateTime.Now < nextReminder.Time)
 						{
-							//Console.WriteLine($"[Rhino/Reminderd] Sleeping for {nextWaitingTime}");
+							Console.WriteLine($"[Rhino/Reminderd] Sleeping for {nextWaitingTime}");
 							await Task.Delay(nextWaitingTime, reminderWatcherResetToken);
 						}
 					}
 					else {
-						//Console.WriteLine("[Rhino/Reminderd] Sleeping until interrupted");
+						Console.WriteLine("[Rhino/Reminderd] Sleeping until interrupted");
 						await Task.Delay(Timeout.Infinite, reminderWatcherResetToken);
 					}
 				}
 				catch (TaskCanceledException)
 				{
-					//Console.WriteLine("[Rhino/Reminderd] Sleep interrupted, recalculating");
-					interruptReminderWatcher();
+					Console.WriteLine("[Rhino/Reminderd] Sleep interrupted, recalculating");
 					continue;
 				}
 
 				if (reminderWatcherResetToken.IsCancellationRequested)
 				{
 					Console.WriteLine("[Rhino/Reminderd] Sleep interrupted, recalculating (but no exception thrown)");
-					interruptReminderWatcher();
 					continue;
 				}
 
 				Console.WriteLine($"[Rhino/Reminderd] Sending notification {nextReminder}");
+				Jid targetJid = nextReminder.Jid; // Apparently nextReminder is null after the sendAndDeleteReminder() call - very odd!
 				sendAndDeleteReminder(nextReminder);
 
 				if (nextWaitingTime.TotalMilliseconds < 0) {
 					client.SendChatMessage(
-						nextReminder.Jid,
+						targetJid,
 						"(Sorry I'm late reminding you! I might not have been running at the time, " +
 						"or you might have scheduled a reminder for the past)"
 					);
@@ -383,15 +383,12 @@ namespace RhinoReminds
 
 		private void sendAndDeleteReminder(Reminder nextReminder)
 		{
-			try
-			{
+			try {
 				client.SendChatMessage(
 					nextReminder.Jid,
 					$"Hello! You asked me to remind you {nextReminder.Message} at {nextReminder.Time}.".Trim().Replace(@"\s+", " ")
 				);
-			}
-			catch (Exception error)
-			{
+			} catch (Exception error) {
 				Console.Error.WriteLine($"[Rhino/Reminderd] Caught error sending message to client: {error}");
 				Console.Error.WriteLine($"[Rhink/Reminderd] Offending reminder: {nextReminder}");
 				client.SendChatMessage(nextReminder.Jid, "Oops! I encountered an error sending you a reminder. Please contact my operator!");
diff --git a/RhinoReminds/ReminderList.cs b/RhinoReminds/ReminderList.cs
index 933acbe..fdb255c 100644
--- a/RhinoReminds/ReminderList.cs
+++ b/RhinoReminds/ReminderList.cs
@@ -6,7 +6,8 @@ using S22.Xmpp;
 
 namespace RhinoReminds
 {
-	public delegate void OnReminderListUpdateHandler(object sender, Reminder newReminder);
+	public class ReminderListUpdateEventArgs : EventArgs {  }
+	public delegate void OnReminderListUpdateHandler(object sender, ReminderListUpdateEventArgs newReminder);
 
 	public class ReminderList
 	{
@@ -32,7 +33,7 @@ namespace RhinoReminds
 				result.TweakTime();
 
 			Reminders.Add(result);
-			OnReminderListUpdate(this, result);
+			OnReminderListUpdate(this, new ReminderListUpdateEventArgs());
 			return result;
 		}
 
@@ -50,6 +51,8 @@ namespace RhinoReminds
 		public void DeleteReminder(Reminder nextReminder) {
 			if (!Reminders.Remove(nextReminder))
 				throw new ApplicationException($"Error: Failed to remove the reminder {nextReminder} from the list!");
+
+			OnReminderListUpdate(this, new ReminderListUpdateEventArgs());
 		}