package com.bookshop.solid.ocp;

import java.math.BigDecimal;

/** Standard post: flat rate, free above the threshold. */
public class StandardShipping implements ShippingRate {

    /** Business rule: "free shipping over GBP 25" -- named so the rule is findable and searchable. */
    static final BigDecimal FREE_SHIPPING_THRESHOLD = new BigDecimal("25.00");
    static final BigDecimal STANDARD_COST = new BigDecimal("3.00");

    @Override
    public String name() {
        return "standard";
    }

    @Override
    public BigDecimal costFor(BigDecimal orderTotal) {
        return orderTotal.compareTo(FREE_SHIPPING_THRESHOLD) >= 0
                ? BigDecimal.ZERO
                : STANDARD_COST;
    }
}