foodie-server/ruoyi-system/src/test/java/com/ruoyi/system/service/impl/PromotionDiscountLimitCheckerTest.java

package com.ruoyi.system.service.impl;

import com.ruoyi.common.exception.ServiceException;
import com.ruoyi.system.domain.PosFood;
import com.ruoyi.system.domain.PromotionActivity;
import com.ruoyi.system.domain.PromotionActivityRule;
import com.ruoyi.system.domain.PromotionCouponBatch;
import com.ruoyi.system.domain.PromotionCouponRule;
import com.ruoyi.system.mapper.PosFoodMapper;
import com.ruoyi.system.service.ISysConfigService;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.junit.jupiter.MockitoExtension;

import java.math.BigDecimal;
import java.util.List;

import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.mockito.Mockito.lenient;
import static org.mockito.Mockito.when;
import static org.mockito.Mockito.reset;

@ExtendWith(MockitoExtension.class)
class PromotionDiscountLimitCheckerTest {

    @Mock
    private ISysConfigService configService;

    @Mock
    private PosFoodMapper posFoodMapper;

    @InjectMocks
    private PromotionDiscountLimitChecker checker;

    @BeforeEach
    void enableTwentyPercentLimit() {
        when(configService.selectConfigByKey("promotion.discount.limit.enabled"))
                .thenReturn("true");
        // type=5 满额免运创建侧不读比例（不预估免运额），lenient 避免严格stub误报
        lenient().when(configService.selectConfigByKey("promotion.discount.limit.ratio"))
                .thenReturn("20");
    }

    @Test
    void fullReductionCouponAllowsExactLimitAndRejectsAmountAboveLimit() {
        PromotionCouponBatch batch = batch(1);

        assertDoesNotThrow(() -> checker.checkCouponBatch(batch,
                rule(null, "100", "20", null)));
        assertThrows(ServiceException.class, () -> checker.checkCouponBatch(batch,
                rule(null, "100", "20.01", null)));
    }

    @Test
    void productDiscountCouponAllowsEightTenthsAndRejectsLowerRate() {
        PromotionCouponBatch batch = batch(2);

        assertDoesNotThrow(() -> checker.checkCouponBatch(batch,
                rule(1L, null, null, "0.80")));
        assertThrows(ServiceException.class, () -> checker.checkCouponBatch(batch,
                rule(1L, null, null, "0.79")));
    }

    @Test
    void productVoucherUsesCurrentProductPriceAsLimitAnchor() {
        when(posFoodMapper.selectById(1L)).thenReturn(food(1L, "100"));
        PromotionCouponBatch batch = batch(2);

        assertDoesNotThrow(() -> checker.checkCouponBatch(batch,
                rule(1L, null, "20", null)));
        assertThrows(ServiceException.class, () -> checker.checkCouponBatch(batch,
                rule(1L, null, "20.01", null)));
    }

    @Test
    void productVoucherDoesNotRoundNinetyNineDollarLimitUpToTwenty() {
        when(posFoodMapper.selectById(1L)).thenReturn(food(1L, "99"));

        assertThrows(ServiceException.class, () -> checker.checkCouponBatch(batch(2),
                rule(1L, null, "20", null)));
    }

    @Test
    void customThirtyPercentRatioChangesAllowedVoucherAmount() {
        when(configService.selectConfigByKey("promotion.discount.limit.ratio"))
                .thenReturn("30");
        when(posFoodMapper.selectById(1L)).thenReturn(food(1L, "100"));
        PromotionCouponBatch batch = batch(2);

        assertDoesNotThrow(() -> checker.checkCouponBatch(batch,
                rule(1L, null, "30", null)));
        assertThrows(ServiceException.class, () -> checker.checkCouponBatch(batch,
                rule(1L, null, "30.01", null)));
    }

    @Test
    void invalidRatioFallsBackToTwentyPercent() {
        when(configService.selectConfigByKey("promotion.discount.limit.ratio"))
                .thenReturn("not-a-number");

        assertEquals(new BigDecimal("20"), checker.getRatioPercent());
        assertThrows(ServiceException.class, () -> checker.checkCouponBatch(batch(1),
                rule(null, "100", "21", null)));
    }

    @Test
    void disabledLimitPreservesPreviousCouponBehavior() {
        reset(configService);
        when(configService.selectConfigByKey("promotion.discount.limit.enabled"))
                .thenReturn("false");

        assertDoesNotThrow(() -> checker.checkCouponBatch(batch(1),
                rule(null, "100", "90", null)));
    }

    @Test
    void freeDeliveryCouponRequiresPositiveThreshold() {
        assertThrows(ServiceException.class, () -> checker.checkCouponBatch(batch(3),
                rule(null, null, "10", null)));
    }

    @Test
    void multiProductCouponRejectsBatchWhenAnyProductExceedsLimit() {
        when(posFoodMapper.selectById(1L)).thenReturn(food(1L, "100"));
        when(posFoodMapper.selectById(2L)).thenReturn(food(2L, "50"));
        List<PromotionCouponRule> rules = List.of(
                rule(1L, null, "20", null),
                rule(2L, null, "11", null));

        assertThrows(ServiceException.class,
                () -> checker.checkCouponBatch(batch(2), rules));
    }

    @Test
    void freeDeliveryActivityCreationSkipsReductionRatioCheck() {
        // T074：type=5 满额免运只有门槛没有减免额，创建侧不预估/不限制实际免运额
        PromotionActivity activity = new PromotionActivity();
        activity.setType(5);
        PromotionActivityRule rule = new PromotionActivityRule();
        rule.setThreshold(new BigDecimal("100"));

        assertDoesNotThrow(() -> checker.checkActivity(activity, List.of(rule)));
    }

    private PromotionCouponBatch batch(int type) {
        PromotionCouponBatch batch = new PromotionCouponBatch();
        batch.setCouponType(type);
        return batch;
    }

    private PromotionCouponRule rule(Long productId, String threshold, String amount,
                                      String discountRate) {
        PromotionCouponRule rule = new PromotionCouponRule();
        rule.setProductId(productId);
        rule.setThreshold(decimal(threshold));
        rule.setAmount(decimal(amount));
        rule.setDiscountRate(decimal(discountRate));
        return rule;
    }

    private PosFood food(Long id, String price) {
        PosFood food = new PosFood();
        food.setId(id);
        food.setName("food-" + id);
        food.setPrice(new BigDecimal(price));
        return food;
    }

    private BigDecimal decimal(String value) {
        return value == null ? null : new BigDecimal(value);
    }
}