Attempt to make !timeleft a bit more accurate

BanchoMultiplayerBot/Behaviour/MapManagerBehaviour.cs

@@ -169,7 +169,7 @@ private void OnMatchStarted()
         _lobby.UpdateSettings();
     }
 
-    private void OnUserMessage(PlayerMessage msg)
+    private async void OnUserMessage(PlayerMessage msg)
     {
         if (msg.Content.ToLower().EndsWith("!r") || msg.Content.ToLower().StartsWith("!regulations"))
         {
@@ -199,9 +199,32 @@ private void OnUserMessage(PlayerMessage msg)
 
         if (msg.Content.ToLower().StartsWith("!timeleft") && _lobby.MultiplayerLobby.MatchInProgress)
         {
-            var timeLeft = (_matchStartTime.Add(CurrentBeatmap.Length) - DateTime.Now).ToString(@"mm\:ss");
+            try
+            {
+                var finishTime = _matchStartTime.Add(CurrentBeatmap.Length);
+
+                // Add a few seconds to account for people loading/finishing the map
+                finishTime = finishTime.AddSeconds(15);
+
+                // If we know where the map starts, we can be a bit more clever and try to account for that.
+                // This obviously assumes that the players skip, and skip at around 50% of that time.
+                var beginSkipTime = await BeatmapParser.GetBeatmapStartTime(CurrentBeatmap.Id);
+                if (beginSkipTime != null)
+                {
+                    finishTime = finishTime.Subtract(TimeSpan.FromSeconds(beginSkipTime.Value * 0.5));
+                }
 
-            msg.Reply($"Estimated time left of current map: {timeLeft}");
+                var timeLeft = (finishTime - DateTime.Now).ToString(@"mm\:ss");
+
+                msg.Reply($"Estimated time left of current map: {timeLeft}");
+
+                if (beginSkipTime == null)
+                    Log.Information("Unable to get map begin time during !timeleft estimation.");
+            }
+            catch (Exception)
+            {
+                // ignored.
+            }
         }
     }
 
@@ -325,6 +348,7 @@ private async Task EnforceBeatmapLimits(BeatmapModel beatmap, MapValidator.MapSt
                 SetId = int.Parse(beatmap.BeatmapsetId ?? "0"),
                 Name = $"{beatmap.Artist} - {beatmap.Title}",
                 Length = TimeSpan.FromSeconds(int.Parse(beatmap.TotalLength ?? "0", CultureInfo.InvariantCulture)),
+                DrainLength = TimeSpan.FromSeconds(int.Parse(beatmap.HitLength ?? "0", CultureInfo.InvariantCulture)),
                 StarRating = float.Parse(beatmap.DifficultyRating ?? "0", CultureInfo.InvariantCulture)
             };
 

BanchoMultiplayerBot/Data/BeatmapInfo.cs

@@ -10,6 +10,8 @@ public class BeatmapInfo
 
     public TimeSpan Length { get; set; }
 
+    public TimeSpan DrainLength { get; set; }
+
     public float StarRating { get; set; }
 
 }

BanchoMultiplayerBot/Utilities/BeatmapParser.cs

@@ -0,0 +1,50 @@
+namespace BanchoMultiplayerBot.Utilities;
+
+public class BeatmapParser
+{
+
+    // Attempt to find the first hit object in seconds, relies on the map being downloaded beforehand
+    public static async Task<int?> GetBeatmapStartTime(int beatmapId)
+    {
+        const string cacheDir = $"cache";
+        var beatmapFilePath = $"{cacheDir}/{beatmapId}.osu";
+
+        try
+        {
+            if (!File.Exists(beatmapFilePath))
+            {
+                return null;
+            }
+
+            var inHitObjectsSection = false;
+            foreach (var line in await File.ReadAllLinesAsync(beatmapFilePath))
+            {
+                if (!line.Any())
+                {
+                    continue;
+                }
+
+                if (line.StartsWith("[HitObjects]"))
+                {
+                    inHitObjectsSection = true;
+                    continue;
+                }
+
+                if (!inHitObjectsSection)
+                {
+                    continue;
+                }
+
+                return int.Parse(line.Split(',')[2]) / 1000;
+            }
+        }
+        catch (Exception)
+        {
+            // ignored
+        }
+
+        return null;
+    }
+
+
+}