from typing import List, Sequence

from .legal_retainer_drawdown_types import RetainerApplication, RetainerBill, RetainerDrawdown
from .money_amount import Money, money


def retainer_drawdown(on_account: Money, bills: Sequence[RetainerBill]) -> RetainerDrawdown:
    """Apply money on account to bills in the order given."""
    currency = on_account.currency
    if on_account.minor < 0:
        raise ValueError("onAccount must not be negative, received %s" % (on_account.minor,))
    left = on_account.minor
    applied = 0
    outstanding = 0
    lines: List[RetainerApplication] = []
    for bill in bills:
        if bill.amount.currency != currency:
            raise ValueError("currency mismatch: %s and %s" % (currency, bill.amount.currency))
        if bill.amount.minor < 0:
            raise ValueError('bill "%s" must not be negative, received %s' % (bill.reference, bill.amount.minor))
        take = min(left, bill.amount.minor)
        left -= take
        applied += take
        outstanding += bill.amount.minor - take
        lines.append(
            RetainerApplication(
                reference=bill.reference,
                billed=bill.amount,
                applied=money(take, currency),
                outstanding=money(bill.amount.minor - take, currency),
            )
        )
    return RetainerDrawdown(
        bills=lines,
        applied=money(applied, currency),
        outstanding=money(outstanding, currency),
        balance=money(left, currency),
    )