fix: parse dates using group's timezone when adding/updating bounties

The parse_args function now accepts timezone_str parameter and uses it
to localize parsed dates. This ensures dates are interpreted in the
group's timezone, not the server's local timezone.

apps/telegram-bot/commands.py

@@ -59,6 +59,7 @@ def extract_args(text: str) -> list[str]:
 
 def parse_args(
     args: list[str],
+    timezone_str: str = "UTC",
 ) -> tuple[Optional[str], Optional[str], Optional[int], bool, bool]:
     text = None
     link = None
@@ -66,6 +67,11 @@ def parse_args(
     clear_link = False
     clear_date = False
 
+    try:
+        tz = ZoneInfo(timezone_str)
+    except (KeyError, ZoneInfoNotFoundError):
+        tz = ZoneInfo("UTC")
+
     def is_url(s: str) -> bool:
         if not s:
             return False
@@ -87,6 +93,13 @@ def parse_args(
         except ValueError:
             return False
 
+    def parse_date_with_tz(date_str: str) -> int | None:
+        parsed = dateparser.parse(date_str)
+        if parsed:
+            localized = parsed.replace(tzinfo=tz)
+            return int(localized.timestamp())
+        return None
+
     i = 0
     while i < len(args):
         arg = args[i]
@@ -100,9 +113,8 @@ def parse_args(
                 i += 1
         elif arg == "-date":
             if i + 1 < len(args):
-                parsed = dateparser.parse(args[i + 1])
-                if parsed:
-                    due_date_ts = int(parsed.timestamp())
+                due_date_ts = parse_date_with_tz(args[i + 1])
+                if due_date_ts is not None:
                     i += 2
                     if i < len(args) and is_time(args[i]):
                         time_parts = args[i].split(":")
@@ -120,9 +132,8 @@ def parse_args(
             link = arg
             i += 1
         elif due_date_ts is None:
-            parsed = dateparser.parse(arg)
-            if parsed:
-                due_date_ts = int(parsed.timestamp())
+            due_date_ts = parse_date_with_tz(arg)
+            if due_date_ts is not None:
                 i += 1
                 if i < len(args) and is_time(args[i]):
                     time_parts = args[i].split(":")
@@ -343,14 +354,15 @@ async def cmd_add(update: Update, ctx: ContextTypes.DEFAULT_TYPE) -> None:
         )
         return
 
-    text, link, due_date_ts, _, _ = parse_args(args)
+    user_id = get_user_id(update)
+    room_id = get_room_id(update)
+    timezone_str = BOUNTY_SERVICE.get_timezone(room_id)
+
+    text, link, due_date_ts, _, _ = parse_args(args, timezone_str)
     if not text and not link:
         await update.message.reply_text("A bounty needs at least text or a link.")
         return
 
-    user_id = get_user_id(update)
-    room_id = get_room_id(update)
-
     try:
         bounty = BOUNTY_SERVICE.add_bounty(
             room_id=room_id,
@@ -397,7 +409,11 @@ async def cmd_update(update: Update, ctx: ContextTypes.DEFAULT_TYPE) -> None:
         await update.message.reply_text("Invalid bounty ID.")
         return
 
-    text, link, due_date_ts, clear_link, clear_date = parse_args(args[1:])
+    user_id = get_user_id(update)
+    room_id = get_room_id(update)
+    timezone_str = BOUNTY_SERVICE.get_timezone(room_id)
+
+    text, link, due_date_ts, clear_link, clear_date = parse_args(args[1:], timezone_str)
     if (
         not text
         and not link
@@ -408,9 +424,6 @@ async def cmd_update(update: Update, ctx: ContextTypes.DEFAULT_TYPE) -> None:
         await update.message.reply_text("Nothing to update.")
         return
 
-    user_id = get_user_id(update)
-    room_id = get_room_id(update)
-
     old_bounty = BOUNTY_SERVICE.get_bounty(room_id, bounty_id)
     if not old_bounty:
         await update.message.reply_text("Bounty not found.")