"""Procurement method: cost = Σ(unit_cost × qty × (1 + markup)) for non-labor items."""


def build(scope, rate, catalog):
    markup = rate.get("procurement_markup", 0.15)
    items, total = [], 0.0
    for it in scope.get("items", []):
        qty = it.get("qty", 1)
        amt = it["unit_cost"] * qty * (1 + markup)
        items.append({"label": it["label"], "unit_cost": it["unit_cost"], "qty": qty,
                      "markup": markup, "amount": amt, "currency": it.get("currency", "KRW")})
        total += amt
    return {
        "kind": "procurement", "service": catalog.get("service", "procurement"),
        "label": "조달 항목 (Buying & Supplying)", "markup": markup,
        "items": items, "subtotal_sum": total, "proposal": int(round(total)),
        "stub": bool(catalog.get("_stub", False)),
    }