"""
core/text.py — small text helpers shared by core/, conditions/ and flows/.

Lives in core/ because core/ must not import from conditions/, pages/ or
flows/, and all three need it (review of unit D, 2026-10-05: the condition
runner, the Charge Summary and the flow each had their own copy).
"""


def first_line(value) -> str:
    """
    The first non-blank line of `value`'s text, stripped.

    For an exception: Playwright's messages carry a whole call log after the
    first line, which is all a log line or a summary cell wants. An exception
    with an empty message gives its class name instead — a bare
    `str(exc).splitlines()[0]` raises IndexError on one. Any other empty
    value (an error string that came back blank) gives "".
    """
    lines = str(value).strip().splitlines()
    if lines:
        return lines[0].strip()
    return type(value).__name__ if isinstance(value, BaseException) else ""