New regex to properly match/parse channel topics.

Author: Jerrie-Aries

cogs/modmail.py

@@ -1848,7 +1848,7 @@ async def repair(self, ctx):
                 and message.embeds[0].color.value == self.bot.main_color
                 and message.embeds[0].footer.text
             ):
-                user_id = match_user_id(message.embeds[0].footer.text)
+                user_id = match_user_id(message.embeds[0].footer.text, any_string=True)
                 other_recipients = match_other_recipients(ctx.channel.topic)
                 for n, uid in enumerate(other_recipients):
                     other_recipients[n] = self.bot.get_user(uid) or await self.bot.fetch_user(uid)

core/thread.py

@@ -17,9 +17,9 @@
 from core.utils import (
     is_image_url,
     days,
+    parse_channel_topic,
     match_title,
     match_user_id,
-    match_other_recipients,
     truncate,
     get_top_hoisted_role,
     create_thread_channel,
@@ -119,17 +119,16 @@ def cancelled(self, flag: bool):
 
     @classmethod
     async def from_channel(cls, manager: "ThreadManager", channel: discord.TextChannel) -> "Thread":
-        recipient_id = match_user_id(
-            channel.topic
-        )  # there is a chance it grabs from another recipient's main thread
+        # there is a chance it grabs from another recipient's main thread
+        _, recipient_id, other_ids = parse_channel_topic(channel.topic)
 
         if recipient_id in manager.cache:
             thread = manager.cache[recipient_id]
         else:
             recipient = manager.bot.get_user(recipient_id) or await manager.bot.fetch_user(recipient_id)
 
             other_recipients = []
-            for uid in match_other_recipients(channel.topic):
+            for uid in other_ids:
                 try:
                     other_recipient = manager.bot.get_user(uid) or await manager.bot.fetch_user(uid)
                 except discord.NotFound:
@@ -1162,23 +1161,31 @@ async def _update_users_genesis(self):
         await genesis_message.edit(embed=embed)
 
     async def add_users(self, users: typing.List[typing.Union[discord.Member, discord.User]]) -> None:
-        title = match_title(self.channel.topic)
-        user_id = match_user_id(self.channel.topic)
+        title, user_id, _ = parse_channel_topic(self.channel.topic)
+        if title is not None:
+            title = f"Title: {title}\n"
+        else:
+            title = ""
+
         self._other_recipients += users
 
         ids = ",".join(str(i.id) for i in self._other_recipients)
-        await self.channel.edit(topic=f"Title: {title}\nUser ID: {user_id}\nOther Recipients: {ids}")
+        await self.channel.edit(topic=f"{title}User ID: {user_id}\nOther Recipients: {ids}")
 
         await self._update_users_genesis()
 
     async def remove_users(self, users: typing.List[typing.Union[discord.Member, discord.User]]) -> None:
-        title = match_title(self.channel.topic)
-        user_id = match_user_id(self.channel.topic)
+        title, user_id, _ = parse_channel_topic(self.channel.topic)
+        if title is not None:
+            title = f"Title: {title}\n"
+        else:
+            title = ""
+
         for u in users:
             self._other_recipients.remove(u)
 
         ids = ",".join(str(i.id) for i in self._other_recipients)
-        await self.channel.edit(topic=f"Title: {title}\nUser ID: {user_id}\nOther Recipients: {ids}")
+        await self.channel.edit(topic=f"{title}User ID: {user_id}\nOther Recipients: {ids}")
 
         await self._update_users_genesis()
 
@@ -1240,16 +1247,24 @@ async def find(
                     await thread.close(closer=self.bot.user, silent=True, delete_channel=False)
                     thread = None
         else:
+
+            def check(topic):
+                _, user_id, other_ids = parse_channel_topic(topic)
+                return recipient_id == user_id or recipient_id in other_ids
+
             channel = discord.utils.find(
-                lambda x: str(recipient_id) in x.topic if x.topic else False,
+                lambda x: (check(x.topic)) if x.topic else False,
                 self.bot.modmail_guild.text_channels,
             )
 
             if channel:
                 thread = await Thread.from_channel(self, channel)
                 if thread.recipient:
-                    # only save if data is valid
-                    self.cache[recipient_id] = thread
+                    # only save if data is valid.
+                    # also the recipient_id here could belong to other recipient,
+                    # it would be wrong if we set it as the dict key,
+                    # so we use the thread id instead
+                    self.cache[thread.id] = thread
                 thread.ready = True
 
         if thread and recipient_id not in [x.id for x in thread.recipients]:
@@ -1265,10 +1280,11 @@ async def _find_from_channel(self, channel):
         searching channel history for genesis embed and
         extracts user_id from that.
         """
-        user_id = -1
 
-        if channel.topic:
-            user_id = match_user_id(channel.topic)
+        if not channel.topic:
+            return None
+
+        _, user_id, other_ids = parse_channel_topic(channel.topic)
 
         if user_id == -1:
             return None
@@ -1282,7 +1298,7 @@ async def _find_from_channel(self, channel):
             recipient = None
 
         other_recipients = []
-        for uid in match_other_recipients(channel.topic):
+        for uid in other_ids:
             try:
                 other_recipient = self.bot.get_user(uid) or await self.bot.fetch_user(uid)
             except discord.NotFound:

core/utils.py

@@ -20,9 +20,11 @@
     "human_join",
     "days",
     "cleanup_code",
+    "parse_channel_topic",
     "match_title",
     "match_user_id",
     "match_other_recipients",
+    "create_thread_channel",
     "create_not_found_embed",
     "parse_alias",
     "normalize_alias",
@@ -218,9 +220,45 @@ def cleanup_code(content: str) -> str:
     return content.strip("` \n")
 
 
-TOPIC_OTHER_RECIPIENTS_REGEX = re.compile(r"Other Recipients:\s*((?:\d{17,21},*)+)", flags=re.IGNORECASE)
-TOPIC_TITLE_REGEX = re.compile(r"\bTitle: (.*)\n(?:User ID: )\b", flags=re.IGNORECASE | re.DOTALL)
-TOPIC_UID_REGEX = re.compile(r"\bUser ID:\s*(\d{17,21})\b", flags=re.IGNORECASE)
+TOPIC_REGEX = re.compile(
+    r"\b(Title: (?P<title>.*)\n)?"
+    r"\bUser ID:\s*(?P<user_id>\d{17,21})\b"
+    r"(\nOther Recipients:\s*(?P<other_ids>(\d{17,21},?)+))?",
+    flags=re.IGNORECASE | re.DOTALL,
+)
+UID_REGEX = re.compile(r"\bUser ID:\s*(\d{17,21})\b", flags=re.IGNORECASE)
+
+
+def parse_channel_topic(text: str) -> typing.Tuple[typing.Optional[str], int, typing.List[int]]:
+    """
+    A helper to parse channel topics and respectivefully returns all the required values
+    at once.
+
+    Parameters
+    ----------
+    text : str
+        The text of channel topic.
+
+    Returns
+    -------
+    Tuple[Optional[str], int, List[int]]
+        A tuple of title, user ID, and other recipients IDs.
+    """
+    title, user_id, other_ids = None, -1, []
+    match = TOPIC_REGEX.search(text)
+    if match is not None:
+        groupdict = match.groupdict()
+        title = groupdict["title"]
+
+        # user ID string is the required one in regex, so if match is found
+        # the value of this won't be None
+        user_id = int(groupdict["user_id"])
+
+        oth_ids = groupdict["other_ids"]
+        if oth_ids:
+            other_ids = list(map(int, oth_ids.split(",")))
+
+    return title, user_id, other_ids
 
 
 def match_title(text: str) -> str:
@@ -237,29 +275,35 @@ def match_title(text: str) -> str:
     Optional[str]
         The title if found.
     """
-    match = TOPIC_TITLE_REGEX.search(text)
-    if match is not None:
-        return match.group(1)
+    return parse_channel_topic(text)[0]
 
 
-def match_user_id(text: str) -> int:
+def match_user_id(text: str, any_string: bool = False) -> int:
     """
     Matches a user ID in the format of "User ID: 12345".
 
     Parameters
     ----------
     text : str
         The text of the user ID.
+    any_string: bool
+        Whether to search any string that matches the UID_REGEX, e.g. not from channel topic.
+        Defaults to False.
 
     Returns
     -------
     int
         The user ID if found. Otherwise, -1.
     """
-    match = TOPIC_UID_REGEX.search(text)
-    if match is not None:
-        return int(match.group(1))
-    return -1
+    user_id = -1
+    if any_string:
+        match = UID_REGEX.search(text)
+        if match is not None:
+            user_id = int(match.group(1))
+    else:
+        user_id = parse_channel_topic(text)[1]
+
+    return user_id
 
 
 def match_other_recipients(text: str) -> typing.List[int]:
@@ -276,10 +320,7 @@ def match_other_recipients(text: str) -> typing.List[int]:
     List[int]
         The list of other recipients IDs.
     """
-    match = TOPIC_OTHER_RECIPIENTS_REGEX.search(text)
-    if match is not None:
-        return list(map(int, match.group(1).split(",")))
-    return []
+    return parse_channel_topic(text)[2]
 
 
 def create_not_found_embed(word, possibilities, name, n=2, cutoff=0.6) -> discord.Embed: