port re from walrinator

stdplugins/re.py

@@ -0,0 +1,85 @@
+from collections import defaultdict, deque
+import re
+
+import regex
+from telethon import events, utils
+
+# Heavily based on
+# https://github.com/SijmenSchoon/regexbot/blob/master/regexbot.py
+
+last_msgs = defaultdict(lambda: deque(maxlen=10))
+
+
+def doit(chat_id, match, original):
+    fr = match.group(1)
+    to = match.group(2)
+    to = to.replace('\\/', '/')
+    try:
+        fl = match.group(3)
+        if fl is None:
+            fl = ''
+        fl = fl[1:]
+    except IndexError:
+        fl = ''
+
+    # Build Python regex flags
+    count = 1
+    flags = 0
+    for f in fl:
+        if f == 'i':
+            flags |= regex.IGNORECASE
+        elif f == 'g':
+            count = 0
+        else:
+            return None, f"Unknown flag: {f}"
+
+    def actually_doit(original):
+        try:
+            s, i = regex.subn(fr, to, original.message,
+                              count=count, flags=flags)
+            if i > 0:
+                return original, s
+        except Exception as e:
+            return None, f"u dun goofed m8: {str(e)}"
+        return None, None
+
+    if original is not None:
+        return actually_doit(original)
+    # Try matching the last few messages
+    for original in reversed(last_msgs[chat_id]):
+        m, s = actually_doit(original)
+        if s is not None:
+            return m, s
+    return None, None
+
+
+async def group_has_regex(group):
+    return any(getattr(x, 'username', None) == 'regexbot'
+               async for x in borg.get_participants(group, search='@regexbot'))
+
+
+@borg.on(events.NewMessage)
+async def on_message(event):
+    chat_id = utils.get_peer_id(await event.input_chat)
+    last_msgs[chat_id].append(event.message)
+
+
+@borg.on(events.NewMessage(
+    pattern=re.compile(r"^s/((?:\\/|[^/])+)/((?:\\/|[^/])*)(/.*)?")))
+async def on_regex(event):
+    if event.forward:
+        return
+    if not event.is_private and await group_has_regex(await event.input_chat):
+        return
+
+    chat_id = utils.get_peer_id(await event.input_chat)
+
+    m, s = doit(chat_id, event.pattern_match, await event.reply_message)
+
+    if m is not None:
+        out = await borg.send_message(await event.input_chat, s, reply_to=m.id)
+        last_msgs[chat_id].append(out)
+    elif s is not None:
+        await event.reply(s)
+
+    raise events.StopPropagation