"""The account filter the activity page's lists share (runs, admin actions, server log, quota): one
filter bar drives them all, so the value it sends means the same on every tab.

The value is an account id, or `none` — the rows no account made (the background) — a value to filter
on, not the absence of a filter.
"""

from sqlalchemy import ColumnElement

NONE = "none"
# The `user` query parameter's shape on every route that takes it.
PATTERN = r"^(none|[0-9]{1,10})$"


def condition(column, value: str) -> ColumnElement[bool]:
    """`column` (an account id column) narrowed to `value`."""
    return column.is_(None) if value == NONE else column == int(value)