Use regex for prefixes

functions/prefixes.py

@@ -1,28 +1,23 @@
 from data.constants import prefixes
 from discord.ext import commands
 import os
+import re
 
 
 fallback = os.urandom(32).hex()
 
 
 def get_prefix(bot: commands.Bot, message):
-    content = message.content.lower()
     mention = "<@!{}>".format(bot.user.id)
+    regex = r"^({})\s*"
 
-    # Used @Didier
-    if content.startswith(mention):
-        if content.startswith(mention + " "):
-            return mention + " "
-        return mention
-
-    # Used a prefix
-    for prefix in prefixes:
-        # Find correct prefix
-        if content.startswith(prefix):
-            # Check if a space has to be added to invoke commands
-            if content.startswith(prefix + " "):
-                return prefix + " "
-            return prefix
+    # Check which prefix was used
+    for prefix in [*prefixes, mention]:
+        r = re.compile(regex.format(prefix), flags=re.I)
+        m = r.match(message.content)
+        if m:
+            # match.group() randomly ignores whitespace for some reason
+            # so use string slicing
+            return message.content[:m.end()]
 
     return fallback