feat(storage): add storage package base

backend/packages/storage/store/utils/__init__.py

@@ -0,0 +1,3 @@
+from .timezone import get_timezone
+
+__all__ = ["get_timezone"]

backend/packages/storage/store/utils/timezone.py

@@ -0,0 +1,51 @@
+import zoneinfo
+from datetime import UTC, datetime
+
+from store.config.app_config import get_app_config
+
+# IANA identifiers that map to UTC — see https://en.wikipedia.org/wiki/List_of_tz_database_time_zones
+_UTC_IDENTIFIERS = frozenset({"Etc/UCT", "Etc/Universal", "Etc/UTC", "Etc/Zulu", "UCT", "Universal", "UTC", "Zulu"})
+
+
+class TimeZone:
+    def __init__(self) -> None:
+        app_config = get_app_config()
+        if app_config.timezone in _UTC_IDENTIFIERS:
+            self.tz_info = UTC
+        else:
+            self.tz_info = zoneinfo.ZoneInfo(app_config.timezone)
+
+    def now(self) -> datetime:
+        """Return the current time in the configured timezone."""
+        return datetime.now(self.tz_info)
+
+    def from_datetime(self, t: datetime) -> datetime:
+        """Convert a datetime to the configured timezone."""
+        return t.astimezone(self.tz_info)
+
+    def from_str(self, t_str: str, format_str: str = "%Y-%m-%d %H:%M:%S") -> datetime:
+        """Parse a time string and attach the configured timezone."""
+        return datetime.strptime(t_str, format_str).replace(tzinfo=self.tz_info)
+
+    @staticmethod
+    def to_str(t: datetime, format_str: str = "%Y-%m-%d %H:%M:%S") -> str:
+        """Format a datetime to string."""
+        return t.strftime(format_str)
+
+    @staticmethod
+    def to_utc(t: datetime | int) -> datetime:
+        """Convert a datetime or Unix timestamp to UTC."""
+        if isinstance(t, datetime):
+            return t.astimezone(UTC)
+        return datetime.fromtimestamp(t, tz=UTC)
+
+
+_timezone = None
+
+
+def get_timezone() -> TimeZone:
+    """Return the global TimeZone singleton (lazy-initialized)."""
+    global _timezone
+    if _timezone is None:
+        _timezone = TimeZone()
+    return _timezone