fix order of command processing, add helper function for sending messages

helpers.py

@@ -1,4 +1,7 @@
 import json
+import time
+
+import constants
 
 HEADER_LENGTH = 10
 
@@ -17,3 +20,15 @@ def prepare_json(object) -> bytes:
     :return: Encoded JSON
     """
     return prepare(json.dumps(object))
+
+
+def prepare_server_message(nickname: str, message: str, color: str, msgtime: int = None):
+    return prepare_json(
+        {
+            'type': constants.Types.MESSAGE,
+            'nickname': nickname,
+            'content': message,
+            'color': color,
+            'time': msgtime or int(time.time())
+        }
+    )