From c02f67e0d1dcabde598d65d346c63097e309d410 Mon Sep 17 00:00:00 2001
From: Tulir Asokan <tulir@maunium.net>
Date: Wed, 23 Jun 2021 18:44:32 +0300
Subject: [PATCH] Send warning if bridge bot doesn't have redaction permissions

---
 mautrix_telegram/commands/portal/bridge.py      |  4 +++-
 mautrix_telegram/commands/portal/create_chat.py |  5 ++++-
 mautrix_telegram/commands/portal/util.py        | 14 ++++++++++++--
 3 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/mautrix_telegram/commands/portal/bridge.py b/mautrix_telegram/commands/portal/bridge.py
index ffe2ff10..33f1a779 100644
--- a/mautrix_telegram/commands/portal/bridge.py
+++ b/mautrix_telegram/commands/portal/bridge.py
@@ -23,7 +23,7 @@ from mautrix.types import EventID, RoomID
 from ...types import TelegramID
 from ... import portal as po
 from .. import command_handler, CommandEvent, SECTION_CREATING_PORTALS
-from .util import user_has_power_level, get_initial_state
+from .util import user_has_power_level, get_initial_state, warn_missing_power
 
 
 @command_handler(needs_auth=False, needs_puppeting=False,
@@ -191,4 +191,6 @@ async def _locked_confirm_bridge(evt: CommandEvent, portal: 'po.Portal', room_id
     asyncio.ensure_future(portal.update_matrix_room(user, entity, direct=False, levels=levels),
                           loop=evt.loop)
 
+    await warn_missing_power(levels, evt)
+
     return await evt.reply("Bridging complete. Portal synchronization should begin momentarily.")
diff --git a/mautrix_telegram/commands/portal/create_chat.py b/mautrix_telegram/commands/portal/create_chat.py
index c48a0f47..fb75e15f 100644
--- a/mautrix_telegram/commands/portal/create_chat.py
+++ b/mautrix_telegram/commands/portal/create_chat.py
@@ -18,7 +18,7 @@ from mautrix.types import EventID
 from ... import portal as po
 from ...types import TelegramID
 from .. import command_handler, CommandEvent, SECTION_CREATING_PORTALS
-from .util import user_has_power_level, get_initial_state
+from .util import user_has_power_level, get_initial_state, warn_missing_power
 
 
 @command_handler(help_section=SECTION_CREATING_PORTALS,
@@ -58,6 +58,9 @@ async def create(evt: CommandEvent) -> EventID:
         await evt.reply(f"Failed to add the following users to the chat:\n\n{error_list}\n\n"
                         "You can try `$cmdprefix+sp search -r <username>` to help the bridge find "
                         "those users.")
+
+    await warn_missing_power(levels, evt)
+
     try:
         await portal.create_telegram_chat(evt.sender, invites=invites, supergroup=supergroup)
     except ValueError as e:
diff --git a/mautrix_telegram/commands/portal/util.py b/mautrix_telegram/commands/portal/util.py
index c3db1a01..c3fbe71f 100644
--- a/mautrix_telegram/commands/portal/util.py
+++ b/mautrix_telegram/commands/portal/util.py
@@ -18,14 +18,16 @@ from typing import Tuple, Optional
 from mautrix.errors import MatrixRequestError
 from mautrix.appservice import IntentAPI
 from mautrix.types import RoomID, EventType, PowerLevelStateEventContent
+from .. import CommandEvent
 
 from ... import user as u
 
 OptStr = Optional[str]
 
 
-async def get_initial_state(intent: IntentAPI, room_id: RoomID
-                            ) -> Tuple[OptStr, OptStr, Optional[PowerLevelStateEventContent], bool]:
+async def get_initial_state(
+    intent: IntentAPI, room_id: RoomID
+) -> Tuple[OptStr, OptStr, Optional[PowerLevelStateEventContent], bool]:
     state = await intent.get_state(room_id)
     title: OptStr = None
     about: OptStr = None
@@ -49,6 +51,14 @@ async def get_initial_state(intent: IntentAPI, room_id: RoomID
     return title, about, levels, encrypted
 
 
+async def warn_missing_power(levels: PowerLevelStateEventContent, evt: CommandEvent) -> None:
+    if levels.get_user_level(evt.az.bot_mxid) < levels.redact:
+        await evt.reply("Warning: The bot does not have privileges to redact messages on Matrix. "
+                        "Message deletions from Telegram will not be bridged unless you give "
+                        "redaction permissions to "
+                        f"[{evt.az.bot_mxid}](https://matrix.to/#/{evt.az.bot_mxid})")
+
+
 async def user_has_power_level(room_id: RoomID, intent: IntentAPI, sender: u.User,
                                event: str) -> bool:
     if sender.is_admin: