public interface CoolingStrategy {

    /**
     * 處理方式
     */
    void handle();

}

public class IceCoolingStrategy implements CoolingStrategy {
    @Override
    public void handle() {
        System.out.println("使用冰塊降溫");
    }
}

public class FanCoolingStrategy implements CoolingStrategy {

    @Override
    public void handle() {
        System.out.println("使用風(fēng)扇降溫");
    }
}

public class AirConditionerCoolingStrategy implements CoolingStrategy {
    @Override
    public void handle() {
        System.out.println("使用空調(diào)降溫");
    }
}

public class CoolingStrategyContext {

    private final CoolingStrategy strategy;

    public CoolingStrategyContext(CoolingStrategy strategy) {
        this.strategy = strategy;
    }

    public void coolingHandle() {
        strategy.handle();
    }

} 

public class Main {
    public static void main(String[] args) {
        
        CoolingStrategyContext context = new CoolingStrategyContext(new FanCoolingStrategy());
        context.coolingHandle();

        context = new CoolingStrategyContext(new AirConditionerCoolingStrategy());
        context.coolingHandle();

        context = new CoolingStrategyContext(new IceCoolingStrategy());
        context.coolingHandle();
    }
} 

/**
 * 優(yōu)惠券折扣計(jì)算接口
 * <p>
 * 優(yōu)惠券類(lèi)型；
 * 1. 直減券
 * 2. 滿(mǎn)減券
 * 3. 折扣券
 * 4. n元購(gòu)
 */
public class CouponDiscountService {

    public double discountAmount(int type, double typeContent, double skuPrice, double typeExt) {
        // 1. 直減券
        if (1 == type) {
            return skuPrice - typeContent;
        }
        // 2. 滿(mǎn)減券
        if (2 == type) {
            if (skuPrice < typeExt) return skuPrice;
            return skuPrice - typeContent;
        }
        // 3. 折扣券
        if (3 == type) {
            return skuPrice * typeContent;
        }
        // 4. n元購(gòu)
        if (4 == type) {
            return typeContent;
        }
        return 0D;
    }

}

public interface ICouponDiscount<T> {

    /**
     * 優(yōu)惠券金額計(jì)算
     * @param couponInfo 券折扣信息；直減、滿(mǎn)減、折扣、N元購(gòu)
     * @param skuPrice   sku金額
     * @return           優(yōu)惠后金額
     */
    BigDecimal discountAmount(T couponInfo, BigDecimal skuPrice);

}

public class MJCouponDiscount implements ICouponDiscount<Map<String,String>>  {

    /**
     * 滿(mǎn)減計(jì)算
     * 1. 判斷滿(mǎn)足x元后-n元，否則不減
     * 2. 最低支付金額1元
     */
    public BigDecimal discountAmount(Map<String,String> couponInfo, BigDecimal skuPrice) {
        String x = couponInfo.get("x");
        String o = couponInfo.get("n");

        // 小于商品金額條件的，直接返回商品原價(jià)
        if (skuPrice.compareTo(new BigDecimal(x)) < 0) return skuPrice;
        // 減去優(yōu)惠金額判斷
        BigDecimal discountAmount = skuPrice.subtract(new BigDecimal(o));
        if (discountAmount.compareTo(BigDecimal.ZERO) < 1) return BigDecimal.ONE;

        return discountAmount;
    }
}

public class ZJCouponDiscount implements ICouponDiscount<Double>  {

    /**
     * 直減計(jì)算
     * 1. 使用商品價(jià)格減去優(yōu)惠價(jià)格
     * 2. 最低支付金額1元
     */
    public BigDecimal discountAmount(Double couponInfo, BigDecimal skuPrice) {
        BigDecimal discountAmount = skuPrice.subtract(new BigDecimal(couponInfo));
        if (discountAmount.compareTo(BigDecimal.ZERO) < 1) return BigDecimal.ONE;
        return discountAmount;
    }

}

public class ZKCouponDiscount implements ICouponDiscount<Double> {


    /**
     * 折扣計(jì)算
     * 1. 使用商品價(jià)格乘以折扣比例，為最后支付金額
     * 2. 保留兩位小數(shù)
     * 3. 最低支付金額1元
     */
    public BigDecimal discountAmount(Double couponInfo, BigDecimal skuPrice) {
        BigDecimal discountAmount = skuPrice.multiply(new BigDecimal(couponInfo)).setScale(2, BigDecimal.ROUND_HALF_UP);
        if (discountAmount.compareTo(BigDecimal.ZERO) < 1) return BigDecimal.ONE;
        return discountAmount;
    }

}

public class NYGCouponDiscount implements ICouponDiscount<Double> {

    /**
     * n元購(gòu)購(gòu)買(mǎi)
     * 1. 無(wú)論原價(jià)多少錢(qián)都固定金額購(gòu)買(mǎi)
     */
    public BigDecimal discountAmount(Double couponInfo, BigDecimal skuPrice) {
        return new BigDecimal(couponInfo);
    }

}

public class Context<T> {

    private ICouponDiscount<T> couponDiscount;

    public Context(ICouponDiscount<T> couponDiscount) {
        this.couponDiscount = couponDiscount;
    }

    public BigDecimal discountAmount(T couponInfo, BigDecimal skuPrice) {
        return couponDiscount.discountAmount(couponInfo, skuPrice);
    }

}

public class ApiTest {

    private Logger logger = LoggerFactory.getLogger(ApiTest.class);

    @Test
    public void test_zj() {
        // 直減；100-10，商品100元
        Context<Double> context = new Context<Double>(new ZJCouponDiscount());
        BigDecimal discountAmount = context.discountAmount(10D, new BigDecimal(100));
        logger.info("測(cè)試結(jié)果：直減優(yōu)惠后金額 {}", discountAmount);
    }

    @Test
    public void test_mj() {
        // 滿(mǎn)100減10，商品100元
        Context<Map<String,String>> context = new Context<Map<String,String>>(new MJCouponDiscount());
        Map<String,String> mapReq = new HashMap<String, String>();
        mapReq.put("x","100");
        mapReq.put("n","10");
        BigDecimal discountAmount = context.discountAmount(mapReq, new BigDecimal(100));
        logger.info("測(cè)試結(jié)果：滿(mǎn)減優(yōu)惠后金額 {}", discountAmount);
    }


    @Test
    public void test_zk() {
        // 折扣9折，商品100元
        Context<Double> context = new Context<Double>(new ZKCouponDiscount());
        BigDecimal discountAmount = context.discountAmount(0.9D, new BigDecimal(100));
        logger.info("測(cè)試結(jié)果：折扣9折后金額 {}", discountAmount);
    }

    @Test
    public void test_nyg() {
        // n元購(gòu)；100-10，商品100元
        Context<Double> context = new Context<Double>(new NYGCouponDiscount());
        BigDecimal discountAmount = context.discountAmount(90D, new BigDecimal(100));
        logger.info("測(cè)試結(jié)果：n元購(gòu)優(yōu)惠后金額 {}", discountAmount);
    }

}