[BE] refactor: 리뷰 랭킹 알고리즘 개선

backend/src/main/java/com/funeat/review/application/ReviewService.java

@@ -1,10 +1,5 @@
 package com.funeat.review.application;
 
-import static com.funeat.member.exception.MemberErrorCode.MEMBER_DUPLICATE_FAVORITE;
-import static com.funeat.member.exception.MemberErrorCode.MEMBER_NOT_FOUND;
-import static com.funeat.product.exception.ProductErrorCode.PRODUCT_NOT_FOUND;
-import static com.funeat.review.exception.ReviewErrorCode.REVIEW_NOT_FOUND;
-
 import com.funeat.common.ImageUploader;
 import com.funeat.common.dto.PageDto;
 import com.funeat.member.domain.Member;
@@ -31,9 +26,6 @@
 import com.funeat.review.persistence.ReviewTagRepository;
 import com.funeat.tag.domain.Tag;
 import com.funeat.tag.persistence.TagRepository;
-import java.util.List;
-import java.util.Optional;
-import java.util.stream.Collectors;
 import org.springframework.dao.DataIntegrityViolationException;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.PageRequest;
@@ -42,13 +34,24 @@
 import org.springframework.transaction.annotation.Transactional;
 import org.springframework.web.multipart.MultipartFile;
 
+import java.util.Comparator;
+import java.util.List;
+import java.util.Optional;
+import java.util.stream.Collectors;
+
+import static com.funeat.member.exception.MemberErrorCode.MEMBER_DUPLICATE_FAVORITE;
+import static com.funeat.member.exception.MemberErrorCode.MEMBER_NOT_FOUND;
+import static com.funeat.product.exception.ProductErrorCode.PRODUCT_NOT_FOUND;
+import static com.funeat.review.exception.ReviewErrorCode.REVIEW_NOT_FOUND;
+
 @Service
 @Transactional(readOnly = true)
 public class ReviewService {
 
     private static final int TOP = 0;
     private static final int ONE = 1;
     private static final String EMPTY_URL = "";
+    private static final int RANKING_SIZE = 3;
 
     private final ReviewRepository reviewRepository;
     private final TagRepository tagRepository;
@@ -156,9 +159,10 @@ public SortingReviewsResponse sortingReviews(final Long productId, final Pageabl
     }
 
     public RankingReviewsResponse getTopReviews() {
-        final List<Review> rankingReviews = reviewRepository.findTop3ByOrderByFavoriteCountDesc();
-
-        final List<RankingReviewDto> dtos = rankingReviews.stream()
+        final List<Review> reviews = reviewRepository.findAll();
+        final List<RankingReviewDto> dtos = reviews.stream()
+                .sorted(Comparator.comparing(Review::calculateRankingScore).reversed())
+                .limit(RANKING_SIZE)
                 .map(RankingReviewDto::toDto)
                 .collect(Collectors.toList());
 

backend/src/main/java/com/funeat/review/domain/Review.java

@@ -3,10 +3,7 @@
 import com.funeat.member.domain.Member;
 import com.funeat.member.domain.favorite.ReviewFavorite;
 import com.funeat.product.domain.Product;
-import java.time.LocalDateTime;
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Objects;
+
 import javax.persistence.Column;
 import javax.persistence.Entity;
 import javax.persistence.FetchType;
@@ -16,10 +13,16 @@
 import javax.persistence.JoinColumn;
 import javax.persistence.ManyToOne;
 import javax.persistence.OneToMany;
+import java.time.LocalDateTime;
+import java.time.temporal.ChronoUnit;
+import java.util.ArrayList;
+import java.util.List;
 
 @Entity
 public class Review {
 
+    private static final double RANKING_GRAVITY = 0.5;
+
     @Id
     @GeneratedValue(strategy = GenerationType.IDENTITY)
     private Long id;
@@ -80,6 +83,18 @@ public Review(final Member member, final Product findProduct, final String image
         this.favoriteCount = favoriteCount;
     }
 
+    public Review(final Member member, final Product findProduct, final String image, final Long rating,
+                  final String content, final Boolean reBuy, final Long favoriteCount, final LocalDateTime createdAt) {
+        this.member = member;
+        this.product = findProduct;
+        this.image = image;
+        this.rating = rating;
+        this.content = content;
+        this.reBuy = reBuy;
+        this.favoriteCount = favoriteCount;
+        this.createdAt = createdAt;
+    }
+
     public void addFavoriteCount() {
         this.favoriteCount++;
     }
@@ -88,6 +103,12 @@ public void minusFavoriteCount() {
         this.favoriteCount--;
     }
 
+    public Double calculateRankingScore() {
+        final long age = ChronoUnit.DAYS.between(createdAt, LocalDateTime.now());
+        final double denominator = Math.pow(age + 1.0, RANKING_GRAVITY);
+        return favoriteCount / denominator;
+    }
+
     public Long getId() {
         return id;
     }

backend/src/test/java/com/funeat/fixture/ReviewFixture.java

@@ -5,6 +5,8 @@
 import com.funeat.review.domain.Review;
 import com.funeat.review.dto.ReviewCreateRequest;
 import com.funeat.review.dto.ReviewFavoriteRequest;
+
+import java.time.LocalDateTime;
 import java.util.List;
 
 @SuppressWarnings("NonAsciiCharacters")
@@ -65,6 +67,11 @@ public class ReviewFixture {
         return new Review(member, product, "test5", 5L, "test", false, count);
     }
 
+    public static Review 리뷰_이미지test5_평점5점_재구매X_생성(final Member member, final Product product, final Long count,
+                                                  final LocalDateTime createdAt) {
+        return new Review(member, product, "test5", 5L, "test", false, count, createdAt);
+    }
+
     public static ReviewCreateRequest 리뷰추가요청_생성(final Long rating, final List<Long> tagIds, final String content,
                                                 final Boolean rebuy) {
         return new ReviewCreateRequest(rating, tagIds, content, rebuy);

backend/src/test/java/com/funeat/review/application/ReviewServiceTest.java

@@ -1,51 +1,37 @@
 package com.funeat.review.application;
 
-import static com.funeat.fixture.CategoryFixture.카테고리_즉석조리_생성;
-import static com.funeat.fixture.ImageFixture.이미지_생성;
-import static com.funeat.fixture.MemberFixture.멤버_멤버1_생성;
-import static com.funeat.fixture.MemberFixture.멤버_멤버2_생성;
-import static com.funeat.fixture.MemberFixture.멤버_멤버3_생성;
-import static com.funeat.fixture.PageFixture.좋아요수_내림차순;
-import static com.funeat.fixture.PageFixture.최신순;
-import static com.funeat.fixture.PageFixture.페이지요청_기본_생성;
-import static com.funeat.fixture.PageFixture.페이지요청_생성;
-import static com.funeat.fixture.PageFixture.평점_내림차순;
-import static com.funeat.fixture.PageFixture.평점_오름차순;
-import static com.funeat.fixture.ProductFixture.상품_삼각김밥_가격1000원_평점2점_생성;
-import static com.funeat.fixture.ProductFixture.상품_삼각김밥_가격1000원_평점3점_생성;
-import static com.funeat.fixture.ProductFixture.상품_삼각김밥_가격1000원_평점5점_생성;
-import static com.funeat.fixture.ProductFixture.상품_삼각김밥_가격2000원_평점1점_생성;
-import static com.funeat.fixture.ProductFixture.상품_삼각김밥_가격2000원_평점3점_생성;
-import static com.funeat.fixture.ReviewFixture.리뷰_이미지test1_평점1점_재구매O_생성;
-import static com.funeat.fixture.ReviewFixture.리뷰_이미지test1_평점1점_재구매X_생성;
-import static com.funeat.fixture.ReviewFixture.리뷰_이미지test2_평점2점_재구매O_생성;
-import static com.funeat.fixture.ReviewFixture.리뷰_이미지test2_평점2점_재구매X_생성;
-import static com.funeat.fixture.ReviewFixture.리뷰_이미지test3_평점3점_재구매O_생성;
-import static com.funeat.fixture.ReviewFixture.리뷰_이미지test3_평점3점_재구매X_생성;
-import static com.funeat.fixture.ReviewFixture.리뷰_이미지test4_평점4점_재구매O_생성;
-import static com.funeat.fixture.ReviewFixture.리뷰_이미지없음_평점1점_재구매O_생성;
-import static com.funeat.fixture.ReviewFixture.리뷰좋아요요청_생성;
-import static com.funeat.fixture.ReviewFixture.리뷰추가요청_재구매O_생성;
-import static com.funeat.fixture.TagFixture.태그_맛있어요_TASTE_생성;
-import static com.funeat.fixture.TagFixture.태그_아침식사_ETC_생성;
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.assertj.core.api.Assertions.assertThatThrownBy;
-import static org.assertj.core.api.SoftAssertions.assertSoftly;
-
 import com.funeat.common.ServiceTest;
 import com.funeat.common.dto.PageDto;
 import com.funeat.member.dto.MemberReviewDto;
 import com.funeat.member.exception.MemberException.MemberNotFoundException;
 import com.funeat.product.exception.ProductException.ProductNotFoundException;
 import com.funeat.review.domain.Review;
+import com.funeat.review.dto.RankingReviewDto;
+import com.funeat.review.dto.RankingReviewsResponse;
 import com.funeat.review.dto.SortingReviewDto;
 import com.funeat.review.exception.ReviewException.ReviewNotFoundException;
 import com.funeat.tag.domain.Tag;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+
+import java.time.LocalDateTime;
+import java.util.Collections;
 import java.util.List;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
-import org.junit.jupiter.api.Nested;
-import org.junit.jupiter.api.Test;
+
+import static com.funeat.fixture.CategoryFixture.카테고리_간편식사_생성;
+import static com.funeat.fixture.CategoryFixture.카테고리_즉석조리_생성;
+import static com.funeat.fixture.ImageFixture.이미지_생성;
+import static com.funeat.fixture.MemberFixture.*;
+import static com.funeat.fixture.PageFixture.*;
+import static com.funeat.fixture.ProductFixture.*;
+import static com.funeat.fixture.ReviewFixture.*;
+import static com.funeat.fixture.TagFixture.태그_맛있어요_TASTE_생성;
+import static com.funeat.fixture.TagFixture.태그_아침식사_ETC_생성;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.assertj.core.api.SoftAssertions.assertSoftly;
 
 @SuppressWarnings("NonAsciiCharacters")
 class ReviewServiceTest extends ServiceTest {
@@ -793,6 +779,155 @@ class updateProductImage_실패_테스트 {
         }
     }
 
+    @Nested
+    class getTopReviews_성공_테스트 {
+
+        @Nested
+        class 리뷰_개수에_대한_테스트 {
+
+            @Test
+            void 전체_리뷰가_하나도_없어도_반환값은_있어야한다() {
+                // given
+                final var expected = RankingReviewsResponse.toResponse(Collections.emptyList());
+
+                // when
+                final var actual = reviewService.getTopReviews();
+
+                // then
+                assertThat(actual).usingRecursiveComparison()
+                        .isEqualTo(expected);
+            }
+
+            @Test
+            void 전체_리뷰가_1개_이상_3개_미만이라도_리뷰가_나와야한다() {
+                // given
+                final var category = 카테고리_간편식사_생성();
+                단일_카테고리_저장(category);
+
+                final var product = 상품_삼각김밥_가격1000원_평점4점_생성(category);
+                단일_상품_저장(product);
+
+                final var member = 멤버_멤버1_생성();
+                단일_멤버_저장(member);
+
+                final var now = LocalDateTime.now();
+                final var review1 = 리뷰_이미지test5_평점5점_재구매X_생성(member, product, 2L, now.minusDays(1L));
+                final var review2 = 리뷰_이미지test5_평점5점_재구매X_생성(member, product, 2L, now);
+                복수_리뷰_저장(review1, review2);
+
+                final var rankingReviewDto1 = RankingReviewDto.toDto(review1);
+                final var rankingReviewDto2 = RankingReviewDto.toDto(review2);
+                final var rankingReviewDtos = List.of(rankingReviewDto2, rankingReviewDto1);
+                final var expected = RankingReviewsResponse.toResponse(rankingReviewDtos);
+
+                // when
+                final var actual = reviewService.getTopReviews();
+
+                // then
+                assertThat(actual).usingRecursiveComparison()
+                        .isEqualTo(expected);
+            }
+
+            @Test
+            void 전체_리뷰_중_랭킹이_높은_상위_3개_리뷰를_구할_수_있다() {
+                // given
+                final var category = 카테고리_간편식사_생성();
+                단일_카테고리_저장(category);
+
+                final var product = 상품_삼각김밥_가격1000원_평점4점_생성(category);
+                단일_상품_저장(product);
+
+                final var member = 멤버_멤버1_생성();
+                단일_멤버_저장(member);
+
+                final var now = LocalDateTime.now();
+                final var review1 = 리뷰_이미지test5_평점5점_재구매X_생성(member, product, 4L, now.minusDays(3L));
+                final var review2 = 리뷰_이미지test5_평점5점_재구매X_생성(member, product, 6L, now.minusDays(2L));
+                final var review3 = 리뷰_이미지test5_평점5점_재구매X_생성(member, product, 4L, now);
+                final var review4 = 리뷰_이미지test5_평점5점_재구매X_생성(member, product, 5L, now);
+                복수_리뷰_저장(review1, review2, review3, review4);
+
+                final var rankingReviewDto1 = RankingReviewDto.toDto(review1);
+                final var rankingReviewDto2 = RankingReviewDto.toDto(review2);
+                final var rankingReviewDto3 = RankingReviewDto.toDto(review3);
+                final var rankingReviewDto4 = RankingReviewDto.toDto(review4);
+                final var rankingReviewDtos = List.of(rankingReviewDto4, rankingReviewDto3, rankingReviewDto2);
+                final var expected = RankingReviewsResponse.toResponse(rankingReviewDtos);
+
+                // when
+                final var actual = reviewService.getTopReviews();
+
+                // then
+                assertThat(actual).usingRecursiveComparison()
+                        .isEqualTo(expected);
+            }
+        }
+
+        @Nested
+        class 리뷰_랭킹_점수에_대한_테스트 {
+
+            @Test
+            void 리뷰_좋아요_수가_같으면_최근_생성된_리뷰의_랭킹을_더_높게_반환한다() {
+                // given
+                final var category = 카테고리_간편식사_생성();
+                단일_카테고리_저장(category);
+
+                final var product = 상품_삼각김밥_가격1000원_평점4점_생성(category);
+                단일_상품_저장(product);
+
+                final var member = 멤버_멤버1_생성();
+                단일_멤버_저장(member);
+
+                final var now = LocalDateTime.now();
+                final var review1 = 리뷰_이미지test5_평점5점_재구매X_생성(member, product, 10L, now.minusDays(9L));
+                final var review2 = 리뷰_이미지test5_평점5점_재구매X_생성(member, product, 10L, now.minusDays(4L));
+                복수_리뷰_저장(review1, review2);
+
+                final var rankingReviewDto1 = RankingReviewDto.toDto(review1);
+                final var rankingReviewDto2 = RankingReviewDto.toDto(review2);
+                final var rankingReviewDtos = List.of(rankingReviewDto2, rankingReviewDto1);
+                final var expected = RankingReviewsResponse.toResponse(rankingReviewDtos);
+
+                // when
+                final var actual = reviewService.getTopReviews();
+
+                // then
+                assertThat(actual).usingRecursiveComparison()
+                        .isEqualTo(expected);
+            }
+
+            @Test
+            void 리뷰_생성_일자가_같으면_좋아요_수가_많은_리뷰의_랭킹을_더_높게_반환한다() {
+                // given
+                final var category = 카테고리_간편식사_생성();
+                단일_카테고리_저장(category);
+
+                final var product = 상품_삼각김밥_가격1000원_평점4점_생성(category);
+                단일_상품_저장(product);
+
+                final var member = 멤버_멤버1_생성();
+                단일_멤버_저장(member);
+
+                final var now = LocalDateTime.now();
+                final var review1 = 리뷰_이미지test5_평점5점_재구매X_생성(member, product, 2L, now.minusDays(1L));
+                final var review2 = 리뷰_이미지test5_평점5점_재구매X_생성(member, product, 4L, now.minusDays(1L));
+                복수_리뷰_저장(review1, review2);
+
+                final var rankingReviewDto1 = RankingReviewDto.toDto(review1);
+                final var rankingReviewDto2 = RankingReviewDto.toDto(review2);
+                final var rankingReviewDtos = List.of(rankingReviewDto2, rankingReviewDto1);
+                final var expected = RankingReviewsResponse.toResponse(rankingReviewDtos);
+
+                // when
+                final var actual = reviewService.getTopReviews();
+
+                // then
+                assertThat(actual).usingRecursiveComparison()
+                        .isEqualTo(expected);
+            }
+        }
+    }
+
     private List<Long> 태그_아이디_변환(final Tag... tags) {
         return Stream.of(tags)
                 .map(Tag::getId)