replace <@___user_id___> with the user's display name in history

When presenting the message history to the bot, replace the
<@00000000> syntax with the user's display name instead.  This is
to help the bot understand the message history, as well as to have
it not "leak" the encoding into its response.

Also, fix a regression in the last commit where we would include
extra lins in the message history.  Ooops!

src/oobabot/discord_bot.py

@@ -594,6 +594,20 @@ async def _filter_history_message(
                 # this is a message generated by our image generator
                 return (None, True)
 
+        if message.channel.guild is None:
+            fn_user_id_to_name = discord_utils.dm_user_id_to_name(
+                self.ai_user_id,
+                self.persona.ai_name,
+            )
+        else:
+            fn_user_id_to_name = discord_utils.guild_user_id_to_name(
+                message.channel.guild,
+            )
+
+        discord_utils.replace_mention_ids_with_names(
+            generic_message,
+            fn_user_id_to_name=fn_user_id_to_name,
+        )
         return (generic_message, True)
 
     async def _filtered_history_iterator(
@@ -617,6 +631,9 @@ async def _filtered_history_iterator(
         last_returned = None
         ignoring_all = ignore_all_until_message_id is not None
         async for item in async_iter_history:
+            if items >= limit:
+                return
+
             if ignoring_all:
                 if item.id == ignore_all_until_message_id:
                     ignoring_all = False

src/oobabot/discord_utils.py

@@ -72,3 +72,63 @@ def discord_message_to_generic_message(
         + f"unsolicited replies disabled.: {raw_message.channel}"
     )
     return types.GenericMessage(**generic_args)
+
+
+def replace_mention_ids_with_names(
+    generic_message: types.GenericMessage,
+    fn_user_id_to_name: typing.Callable[[re.Match[str]], str],
+):
+    """
+    Replace user ID mentions with the user's chosen display
+    name in the given guild (aka server)
+    """
+    # it looks like normal IDs are 18 digits.  But give it some
+    # wiggle room in case things change in the future.
+    # e.g.: <@009999999999999999>
+    at_mention_pattern = r"<@(\d{16,20})>"
+    while True:
+        match = re.search(at_mention_pattern, generic_message.body_text)
+        if not match:
+            break
+        generic_message.body_text = (
+            generic_message.body_text[: match.start()]
+            + fn_user_id_to_name(match)
+            + generic_message.body_text[match.end() :]
+        )
+
+
+def dm_user_id_to_name(
+    bot_user_id: int,
+    bot_name: str,
+) -> typing.Callable[[re.Match[str]], str]:
+    """
+    Replace user ID mentions with the bot's name.  Used when
+    we are in a DM with the bot.
+    """
+    if " " in bot_name:
+        bot_name = f'"{bot_name}"'
+
+    def _replace_user_id_mention(match: typing.Match[str]) -> str:
+        user_id = int(match.group(1))
+        print(f"bot_user_id={bot_user_id}, user_id={user_id}")
+        if user_id == bot_user_id:
+            return f"@{bot_name}"
+        return match.group(0)
+
+    return _replace_user_id_mention
+
+
+def guild_user_id_to_name(
+    guild: discord.Guild,
+) -> typing.Callable[[re.Match[str]], str]:
+    def _replace_user_id_mention(match: typing.Match[str]) -> str:
+        user_id = int(match.group(1))
+        member = guild.get_member(user_id)
+        if member is None:
+            return match.group(0)
+        display_name = member.display_name
+        if " " in display_name:
+            display_name = f'"{display_name}"'
+        return f"@{display_name}"
+
+    return _replace_user_id_mention