from typing import Dict

MIN_ORDER_AMOUNT: int = 10
HIGH_SPENDING_THRESHOLD: int = 100

DISCOUNT_RATES: Dict = {
    "gold" : { "high": 0.20, "low": 0.10},
    "silver" : { "high": 0.10, "low": 0.05}
}

def get_subtotal(items: list[dict]) -> float:
    return sum(item["price"] * item["quantity"] for item in items)

def calculate_order_discount(items: list, membership: str) -> float:
    subtotal: float = get_subtotal(items)

    if subtotal < MIN_ORDER_AMOUNT:
        return -1.0

    rates: Dict = DISCOUNT_RATES.get(membership.lower())

    if not rates:
        return float(subtotal)

    discount_percentage = (
        rates["high"] if subtotal >= HIGH_SPENDING_THRESHOLD else rates["low"]
    )

    result: float = subtotal * (1 - discount_percentage)

    return result

exports = calculate_order_discount