from .finance_tax_add_vat_types import VatBreakdown
from .finance_tax_vat_rate import vat_rate
from .money_add import add_money
from .money_amount import Money
from .money_apply_rate import apply_rate


def add_vat(net: Money, jurisdiction: str, category: str, on_date: str) -> VatBreakdown:
    """Add VAT to a net amount at the rate in force on the date of supply.

    Returns the whole breakdown rather than just the tax: an invoice needs net,
    tax and gross together, and deriving the third from the other two in caller
    code is where rounding bugs are born.
    """
    rate = vat_rate(jurisdiction, category, on_date)
    tax = apply_rate(net, rate.basis_points, "half-up")
    return VatBreakdown(
        net=net,
        tax=tax,
        gross=add_money(net, tax),
        basis_points=rate.basis_points,
    )