from __future__ import annotations

from decimal import Decimal, InvalidOperation

from app.domain.units import decimal_from_float, to_decimal


def boundary_decimal(value: object, *, field_name: str) -> Decimal:
    if value is None:
        raise ValueError(f"{field_name} must be present")
    if isinstance(value, bool):
        raise TypeError(f"{field_name} must be numeric, got bool")
    if isinstance(value, float):
        return decimal_from_float(value)
    if isinstance(value, (Decimal, int)):
        return to_decimal(value)
    if isinstance(value, str):
        stripped = value.strip()
        if not stripped:
            raise ValueError(f"{field_name} must be present")
        try:
            return to_decimal(stripped)
        except InvalidOperation as exc:
            raise ValueError(f"{field_name} must be numeric, got {value!r}") from exc
    raise TypeError(f"{field_name} must be numeric, got {type(value)!r}")