Support mentioning users

This currently has the limitation that the user has to be known to
wee-slack for the mention to work. That is, there needs to be some
interaction with it (message or reaction from or mention) or it has to
be in the loaded members in any of the loaded conversations.

1 files changed, 24 insertions, 3 deletions

diff --git a/slack/slack_buffer.py b/slack/slack_buffer.py
index e6ec532..20dc86c 100644
--- a/slack/slack_buffer.py
+++ b/slack/slack_buffer.py
@@ -4,14 +4,14 @@ import re
 import time
 from abc import ABC, abstractmethod
 from contextlib import contextmanager
-from typing import TYPE_CHECKING, Dict, List, Mapping, Optional, Set, Tuple
+from typing import TYPE_CHECKING, Dict, List, Mapping, Match, Optional, Set, Tuple
 
 import weechat
 
 from slack.log import print_error
 from slack.shared import shared
 from slack.slack_message import SlackMessage, SlackTs
-from slack.task import run_async
+from slack.task import gather, run_async
 from slack.util import get_callback_name, htmlescape
 
 if TYPE_CHECKING:
@@ -404,6 +404,26 @@ class SlackBuffer(ABC):
             else:
                 print_error("The regex didn't match any part of the message")
 
+    async def linkify_text(self, text: str) -> str:
+        escaped_text = htmlescape(text)
+
+        users = await gather(*self.workspace.users.values(), return_exceptions=True)
+        nick_to_user_id = {
+            user.nick(only_nick=True): user.id
+            for user in users
+            if not isinstance(user, BaseException)
+        }
+
+        def linkify_word(match: Match[str]) -> str:
+            word = match.group(0)
+            nick = match.group(1)
+            if nick in nick_to_user_id:
+                return "<@{}>".format(nick_to_user_id[nick])
+            return word
+
+        linkify_regex = r"(?:^|(?<=\s))@([\w\(\)\'.-]+)"
+        return re.sub(linkify_regex, linkify_word, escaped_text, flags=re.UNICODE)
+
     async def process_input(self, input_data: str):
         special = re.match(
             rf"{MESSAGE_ID_REGEX_STRING}?(?:{REACTION_CHANGE_REGEX_STRING}{EMOJI_CHAR_OR_NAME_REGEX_STRING}\s*|s/)",
@@ -438,7 +458,8 @@ class SlackBuffer(ABC):
         else:
             if input_data.startswith(("//", " ")):
                 input_data = input_data[1:]
-            await self.post_message(htmlescape(input_data))
+            text = await self.linkify_text(input_data)
+            await self.post_message(text)
 
     def _buffer_input_cb(self, data: str, buffer: str, input_data: str) -> int:
         run_async(self.process_input(input_data))