Dad jokes are nice

DeukBot4/MessageHandlers/MainHandler.cs

@@ -24,6 +24,7 @@ namespace DeukBot4.MessageHandlers
                 HandlePrivateMessage(message);
                 ImageBackupHandler.Backup(message);
                 DeltaHandler(message);
+                DadJokeHandler(message);
 #pragma warning restore 4014
             }
             catch (Exception e)
@@ -75,5 +76,34 @@ namespace DeukBot4.MessageHandlers
             }
 
         }
+
+        private static async Task DadJokeHandler(SocketMessage message)
+        {
+            if (!(message.Author is IGuildUser guildUser))
+                return;
+            string newName;
+            var lower = message.Content.ToLowerInvariant();
+
+            if (lower.StartsWith("i'm "))
+            {
+                newName = message.Content.Remove(0, 4);
+            }
+            else if (lower.StartsWith("im "))
+            {
+                newName = message.Content.Remove(0, 3);
+            }
+            else if (lower.StartsWith("i am "))
+            {
+                newName = message.Content.Remove(0, 5);
+            }
+            else
+            {
+                return;
+            }
+
+            await message.Channel.SendMessageAsync($"Hi {newName}, i'm Deukbot");
+            await guildUser.ModifyAsync(user => user.Nickname = newName);
+
+        }
     }
 }