upd

main.py

@@ -3,6 +3,7 @@ import time
 import random
 import string
 import asyncio
+from datetime import datetime, timedelta
 from collections import namedtuple
 
 from dotenv import load_dotenv
@@ -38,7 +39,9 @@ load_dotenv()
 API_ID = int(os.getenv("API_ID"))
 API_HASH = os.getenv("API_HASH")
 BOT_TOKEN = os.getenv("BOT_TOKEN")
-ALLOWED_GROUPS = set(map(lambda cid: int("-100" + cid), os.getenv("ALLOWED_GROUPS").split(",")))
+ALLOWED_GROUPS = set(
+    map(lambda cid: int("-100" + cid), os.getenv("ALLOWED_GROUPS").split(","))
+)
 CAPTCHA_WAIT_TIME = int(os.getenv("CAPTCHA_WAIT_TIME", 80))
 MAX_CAPTCHA_ATTEMPTS = int(os.getenv("MAX_CAPTCHA_ATTEMPTS", 8))
 
@@ -51,6 +54,7 @@ class PendingUser:
         self.peer_id = peer_id
         self.user_id = user_id
 
+        self.text = None
         self.message_id = None
 
         self.captcha = None
@@ -66,22 +70,38 @@ class PendingUser:
     async def start(self, event):
         await self.update_captcha()
 
+        self.text = f"Welcome, {get_link_to_user(event.user)}! Please write a message with the **four latin letters (case insensitive)** that appear in this image to verify that you are a human. If you don't solve the captcha in **{CAPTCHA_WAIT_TIME}** seconds, you will be automatically kicked out of the group."
+
         message = await bot.send_message(
             event.chat_id,
-            f"Welcome, {get_link_to_user(event.user)}! Please write a message with the letters that appear in this image to verify that you are a human. If you don't solve the captcha in {CAPTCHA_WAIT_TIME} seconds, you will be automatically kicked out of the group.",
+            self.text,
             file=self.captcha_im,
         )
 
         self.message_id = message
 
-    async def update_captcha(self):
-        self.captcha = "".join(random.sample(string.ascii_uppercase, 4))
-        self.captcha_im = ImageCaptcha().generate(self.captcha)
+    async def update_captcha(self, only_text=False):
+        if not only_text:
+            self.captcha = "".join(random.sample(string.ascii_uppercase, 4))
+            self.captcha_im = ImageCaptcha().generate(self.captcha)
 
-        self.captcha_im.name = "captcha.png"
+            self.captcha_im.name = "captcha.png"
 
         if self.message_id is not None:
-            await bot.edit_message(self.peer_id, self.message_id, file=self.captcha_im)
+            try:
+                attempts = MAX_CAPTCHA_ATTEMPTS - self.retries
+
+                message = await bot.edit_message(
+                    self.peer_id,
+                    self.message_id,
+                    text=self.text
+                    + f"\n\nYou have **{attempts}** attempt{'' if attempts == 1 else 's'} left.",
+                    file=None if only_text else self.captcha_im,
+                )
+
+                self.message_id = message.id
+            except Exception:
+                pass
 
     async def check_captcha(self, captcha):
         captcha = captcha.strip().upper()
@@ -101,7 +121,12 @@ class PendingUser:
         if self.retries > MAX_CAPTCHA_ATTEMPTS:
             await self.kick()
         else:
-            await self.update_captcha()
+            await self.update_captcha(
+                only_text=not (
+                    len(captcha) == 4
+                    and all(map(lambda c: c in string.ascii_uppercase, captcha))
+                )
+            )
 
         return False
 
@@ -124,7 +149,10 @@ class PendingUser:
                 EditBannedRequest(
                     self.peer_id,
                     self.user_id,
-                    ChatBannedRights(until_date=None, view_messages=True),
+                    ChatBannedRights(
+                        until_date=datetime.now() + timedelta(minutes=5),
+                        view_messages=True,
+                    ),
                 )
             )
         except Exception:
@@ -164,7 +192,9 @@ async def handler(event):
     except Exception:
         pass
 
-    await pending_user.check_captcha(event.text)
+    text = getattr(event, "text", "")
+
+    await pending_user.check_captcha(text)
 
 
 async def check_pending():