from .math_basis_points_convert_rate import convert_rate
from .math_basis_points_types import RateUnit

_MAX_SAFE = 9007199254740991


def to_basis_points(value: str, unit: RateUnit) -> int:
    """A rate as whole basis points, the unit the registry keeps rates in.

    Refuses a rate that is not a whole number of basis points (12.345% is
    1234.5) rather than round it: which way to round a rate is the caller's
    policy, not a conversion's.
    """
    text = convert_rate(value, unit, "basis-points")
    if "." in text:
        raise ValueError("%s %s is not a whole number of basis points" % (value, unit))
    bp = int(text)
    if bp > _MAX_SAFE or bp < -_MAX_SAFE:
        raise ValueError("%s %s is too large for integer basis points" % (value, unit))
    return bp