Implements purge messages command

DeukBot4/MessageHandlers/CommandHandler/Commands/ModeratorCommands.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Linq;
 using System.Threading.Tasks;
 using DeukBot4.Database.ServerSettings;
 using DeukBot4.MessageHandlers.CommandHandler.RequestStructure;
@@ -13,6 +14,32 @@ namespace DeukBot4.MessageHandlers.CommandHandler
     {
         public override string Name => "Moderator";
 
+        [Command("purge", PermissionLevel.Moderator)]
+        [CommandHelp("Purges a set number of messages",
+            "Purges a set number of messages. \n" +
+            "Usage: \n"                                                                              +
+            "``!purge {number}`")]
+        [CommandParameters(ParameterMatcher.ParameterType.Number)]
+        [BlockUsageInPm, RequireParameterMatch]
+        public async Task PurgeMessages(CommandRequest request)
+        {
+            // get the server channel object out of message. Return if it's somehow not a server channel
+            if (!(request.OriginalMessage.Channel is ITextChannel channel))
+                return;
+            var messageCountParameter = request.Parameters[0].AsInt();
+            if (!messageCountParameter.HasValue)
+                return;
+            var messageCount = messageCountParameter.Value;
+            var messages = channel.GetMessagesAsync(request.OriginalMessage, Direction.Before, messageCount);
+            messages.ForEachAsync(x =>
+            {
+                foreach (var message in x)
+                {
+                    message.DeleteAsync();
+                }
+            });
+        }
+
         [Command("kick", PermissionLevel.Moderator)]
         [CommandParameters(ParameterMatcher.ParameterType.User, ParameterMatcher.ParameterType.Remainder)]
         [CommandHelp("Kicks a user from the server",