package com.ruoyi.order.service.impl;

import com.ruoyi.other.api.domain.TCoupon;
import org.junit.jupiter.api.Test;

import java.math.BigDecimal;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertThrows;

class ChargingCouponSupportTest {

    @Test
    void fullReductionDiscountsThePrepaymentBeforeThirdPartyPay() {
        TCoupon coupon = chargingCoupon(1);
        coupon.setMeetTheConditions(new BigDecimal("3"));
        coupon.setDiscountAmount(new BigDecimal("1"));

        BigDecimal discount = ChargingCouponSupport.calculateUpfrontDiscount(coupon, new BigDecimal("3"));

        assertEquals(new BigDecimal("1.00"), discount);
        assertEquals(new BigDecimal("2.00"), new BigDecimal("3").subtract(discount));
    }

    @Test
    void percentageDiscountHonorsMaximumDiscount() {
        TCoupon coupon = chargingCoupon(2);
        coupon.setMeetTheConditions(new BigDecimal("10"));
        coupon.setDiscount(new BigDecimal("8"));
        coupon.setMaximumDiscountAmount(new BigDecimal("1.50"));

        BigDecimal discount = ChargingCouponSupport.calculateUpfrontDiscount(coupon, new BigDecimal("10"));

        assertEquals(new BigDecimal("1.50"), discount);
    }

    @Test
    void rejectsPrepaymentBelowCouponThreshold() {
        TCoupon coupon = chargingCoupon(1);
        coupon.setMeetTheConditions(new BigDecimal("3"));
        coupon.setDiscountAmount(new BigDecimal("1"));

        IllegalArgumentException error = assertThrows(IllegalArgumentException.class,
                () -> ChargingCouponSupport.calculateUpfrontDiscount(coupon, new BigDecimal("2.99")));

        assertEquals("预付金额未达到优惠券使用门槛", error.getMessage());
    }

    private TCoupon chargingCoupon(int preferentialMode) {
        TCoupon coupon = new TCoupon();
        coupon.setType(1);
        coupon.setPreferentialMode(preferentialMode);
        return coupon;
    }
}