[BE] feat: 상품 랭킹 기능 추가

backend/src/main/java/com/funeat/product/application/ProductService.java

@@ -4,14 +4,18 @@
 import com.funeat.product.domain.Product;
 import com.funeat.product.dto.ProductInCategoryDto;
 import com.funeat.product.dto.ProductResponse;
+import com.funeat.product.dto.ProductReviewCountDto;
 import com.funeat.product.dto.ProductsInCategoryPageDto;
 import com.funeat.product.dto.ProductsInCategoryResponse;
+import com.funeat.product.dto.RankingProductDto;
+import com.funeat.product.dto.RankingProductsResponse;
 import com.funeat.product.persistence.CategoryRepository;
 import com.funeat.product.persistence.ProductRepository;
-import com.funeat.review.persistence.ReviewRepository;
 import com.funeat.review.persistence.ReviewTagRepository;
 import com.funeat.tag.domain.Tag;
+import java.util.Comparator;
 import java.util.List;
+import java.util.stream.Collectors;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.PageRequest;
 import org.springframework.data.domain.Pageable;
@@ -28,14 +32,12 @@ public class ProductService {
 
     private final CategoryRepository categoryRepository;
     private final ProductRepository productRepository;
-    private final ReviewRepository reviewRepository;
     private final ReviewTagRepository reviewTagRepository;
 
     public ProductService(final CategoryRepository categoryRepository, final ProductRepository productRepository,
-                          final ReviewRepository reviewRepository, final ReviewTagRepository reviewTagRepository) {
+                          final ReviewTagRepository reviewTagRepository) {
         this.categoryRepository = categoryRepository;
         this.productRepository = productRepository;
-        this.reviewRepository = reviewRepository;
         this.reviewTagRepository = reviewTagRepository;
     }
 
@@ -68,4 +70,19 @@ public ProductResponse findProductDetail(final Long productId) {
 
         return ProductResponse.toResponse(product, tags);
     }
+
+    public RankingProductsResponse getTop3Products() {
+        final List<ProductReviewCountDto> productsAndReviewCounts = productRepository.findAllByAverageRatingGreaterThan3();
+        final Comparator<ProductReviewCountDto> rankingScoreComparator = Comparator.comparing(
+                (ProductReviewCountDto it) -> it.getProduct().calculateRankingScore(it.getReviewCount())
+        ).reversed();
+
+        final List<RankingProductDto> rankingProductDtos = productsAndReviewCounts.stream()
+                .sorted(rankingScoreComparator)
+                .limit(3)
+                .map(it -> RankingProductDto.toDto(it.getProduct()))
+                .collect(Collectors.toList());
+
+        return RankingProductsResponse.toResponse(rankingProductDtos);
+    }
 }

backend/src/main/java/com/funeat/product/domain/Product.java

@@ -68,6 +68,12 @@ public void updateAverageRating(final Long rating, final Long count) {
         this.averageRating = Math.round(calculatedRating * 10.0) / 10.0;
     }
 
+    public Double calculateRankingScore(final Long reviewCount) {
+        final double exponent = -Math.log10(reviewCount + 1);
+        final double factor = Math.pow(2, exponent);
+        return averageRating - (averageRating - 3.0) * factor;
+    }
+
     public Long getId() {
         return id;
     }

backend/src/main/java/com/funeat/product/dto/ProductReviewCountDto.java

@@ -0,0 +1,22 @@
+package com.funeat.product.dto;
+
+import com.funeat.product.domain.Product;
+
+public class ProductReviewCountDto {
+
+    private final Product product;
+    private final Long reviewCount;
+
+    public ProductReviewCountDto(final Product product, final Long reviewCount) {
+        this.product = product;
+        this.reviewCount = reviewCount;
+    }
+
+    public Product getProduct() {
+        return product;
+    }
+
+    public Long getReviewCount() {
+        return reviewCount;
+    }
+}

backend/src/main/java/com/funeat/product/dto/RankingProductDto.java

@@ -0,0 +1,32 @@
+package com.funeat.product.dto;
+
+import com.funeat.product.domain.Product;
+
+public class RankingProductDto {
+
+    private final Long id;
+    private final String name;
+    private final String image;
+
+    public RankingProductDto(final Long id, final String name, final String image) {
+        this.id = id;
+        this.name = name;
+        this.image = image;
+    }
+
+    public static RankingProductDto toDto(final Product product) {
+        return new RankingProductDto(product.getId(), product.getName(), product.getImage());
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public String getImage() {
+        return image;
+    }
+}

backend/src/main/java/com/funeat/product/dto/RankingProductsResponse.java

@@ -0,0 +1,20 @@
+package com.funeat.product.dto;
+
+import java.util.List;
+
+public class RankingProductsResponse {
+
+    private final List<RankingProductDto> products;
+
+    public RankingProductsResponse(final List<RankingProductDto> products) {
+        this.products = products;
+    }
+
+    public static RankingProductsResponse toResponse(final List<RankingProductDto> products) {
+        return new RankingProductsResponse(products);
+    }
+
+    public List<RankingProductDto> getProducts() {
+        return products;
+    }
+}

backend/src/main/java/com/funeat/product/persistence/ProductRepository.java

@@ -3,13 +3,16 @@
 import com.funeat.product.domain.Category;
 import com.funeat.product.domain.Product;
 import com.funeat.product.dto.ProductInCategoryDto;
+import com.funeat.product.dto.ProductReviewCountDto;
+import java.util.List;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.data.jpa.repository.Query;
 import org.springframework.data.repository.query.Param;
 
 public interface ProductRepository extends JpaRepository<Product, Long> {
+
     @Query(value = "SELECT new com.funeat.product.dto.ProductInCategoryDto(p.id, p.name, p.price, p.image, p.averageRating, COUNT(r)) " +
             "FROM Product p " +
             "LEFT JOIN p.reviews r " +
@@ -26,4 +29,11 @@ public interface ProductRepository extends JpaRepository<Product, Long> {
             "ORDER BY COUNT(r) DESC, p.id DESC ",
             countQuery = "SELECT COUNT(p) FROM Product p WHERE p.category = :category")
     Page<ProductInCategoryDto> findAllByCategoryOrderByReviewCountDesc(@Param("category") final Category category, final Pageable pageable);
+
+    @Query("SELECT new com.funeat.product.dto.ProductReviewCountDto(p, COUNT(r.id)) "
+            + "FROM Product p "
+            + "LEFT JOIN Review r ON r.product.id = p.id "
+            + "WHERE p.averageRating > 3.0 "
+            + "GROUP BY p.id")
+    List<ProductReviewCountDto> findAllByAverageRatingGreaterThan3();
 }

backend/src/main/java/com/funeat/product/presentation/ProductApiController.java

@@ -3,6 +3,7 @@
 import com.funeat.product.application.ProductService;
 import com.funeat.product.dto.ProductResponse;
 import com.funeat.product.dto.ProductsInCategoryResponse;
+import com.funeat.product.dto.RankingProductsResponse;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.web.PageableDefault;
 import org.springframework.http.ResponseEntity;
@@ -35,4 +36,10 @@ public ResponseEntity<ProductResponse> getProductDetail(@PathVariable final Long
         final ProductResponse response = productService.findProductDetail(productId);
         return ResponseEntity.ok(response);
     }
+
+    @GetMapping("/ranks/products")
+    public ResponseEntity<RankingProductsResponse> getRankingProducts() {
+        final RankingProductsResponse response = productService.getTop3Products();
+        return ResponseEntity.ok(response);
+    }
 }

backend/src/main/java/com/funeat/product/presentation/ProductController.java

@@ -2,6 +2,7 @@
 
 import com.funeat.product.dto.ProductResponse;
 import com.funeat.product.dto.ProductsInCategoryResponse;
+import com.funeat.product.dto.RankingProductsResponse;
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.responses.ApiResponse;
 import io.swagger.v3.oas.annotations.tags.Tag;
@@ -31,4 +32,12 @@ ResponseEntity<ProductsInCategoryResponse> getAllProductsInCategory(
     )
     @GetMapping
     ResponseEntity<ProductResponse> getProductDetail(@PathVariable final Long productId);
+
+    @Operation(summary = "전체 상품 랭킹 조회", description = "전체 상품들 중에서 랭킹 TOP3를 조회한다.")
+    @ApiResponse(
+            responseCode = "200",
+            description = "전체 상품 랭킹 조회 성공."
+    )
+    @GetMapping
+    ResponseEntity<RankingProductsResponse> getRankingProducts();
 }

backend/src/test/java/com/funeat/acceptance/product/ProductAcceptanceTest.java

@@ -6,6 +6,7 @@
 import static com.funeat.acceptance.product.ProductSteps.간편식사;
 import static com.funeat.acceptance.product.ProductSteps.공통_상품_카테고리_목록_조회_요청;
 import static com.funeat.acceptance.product.ProductSteps.과자류;
+import static com.funeat.acceptance.product.ProductSteps.상품_랭킹_조회_요청;
 import static com.funeat.acceptance.product.ProductSteps.상품_상세_조회_요청;
 import static com.funeat.acceptance.product.ProductSteps.즉석조리;
 import static com.funeat.acceptance.product.ProductSteps.카테고리별_상품_목록_조회_요청;
@@ -21,6 +22,7 @@
 import com.funeat.product.dto.ProductInCategoryDto;
 import com.funeat.product.dto.ProductResponse;
 import com.funeat.product.dto.ProductsInCategoryPageDto;
+import com.funeat.product.dto.RankingProductDto;
 import com.funeat.review.domain.Review;
 import com.funeat.review.presentation.dto.ReviewCreateRequest;
 import com.funeat.tag.domain.Tag;
@@ -31,6 +33,7 @@
 import io.restassured.specification.MultiPartSpecification;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.stream.Collectors;
 import org.junit.jupiter.api.Nested;
 import org.junit.jupiter.api.Test;
 
@@ -412,6 +415,38 @@ class 리뷰수_기준_내림차순으로_카테고리별_상품_목록_조회 {
         공통_상품_카테고리_목록_조회_결과를_검증한다(response, List.of(간편식사, 즉석조리, 과자류));
     }
 
+    @Test
+    void 전체_상품들_중에서_랭킹_TOP3를_조회할_수_있다() {
+        // given
+        카테고리_추가_요청(간편식사);
+        final var product1 = new Product("삼각김밥1", 1000L, "image.png", "맛있는 삼각김밥1", 3.25, 간편식사);
+        final var product2 = new Product("삼각김밥2", 2000L, "image.png", "맛있는 삼각김밥2", 4.0, 간편식사);
+        final var product3 = new Product("삼각김밥3", 1500L, "image.png", "맛있는 삼각김밥3", 3.33, 간편식사);
+        final var product4 = new Product("삼각김밥4", 1200L, "image.png", "맛있는 삼각김밥4", 0.0, 간편식사);
+        복수_상품_추가_요청(List.of(product1, product2, product3, product4));
+
+        final var member = 멤버_추가_요청(new Member("test", "image.png", "1"));
+        final var review1_1 = new Review(member, product1, "review.png", 3L, "이 삼각김밥은 맛있다", true);
+        final var review1_2 = new Review(member, product1, "review.png", 3L, "이 삼각김밥은 맛있다", true);
+        final var review1_3 = new Review(member, product1, "review.png", 4L, "이 삼각김밥은 좀 맛있다", true);
+        final var review1_4 = new Review(member, product1, "review.png", 3L, "이 삼각김밥은 최고!!", true);
+        final var review2_1 = new Review(member, product2, "review.png", 4L, "이 삼각김밥은 그럭저럭", false);
+        final var review2_2 = new Review(member, product2, "review.png", 4L, "이 삼각김밥은 굿", false);
+        final var review3_1 = new Review(member, product3, "review.png", 2L, "이 삼각김밥은 좀 맛없다", false);
+        final var review3_2 = new Review(member, product3, "review.png", 3L, "이 삼각김밥은 흠", false);
+        final var review3_3 = new Review(member, product3, "review.png", 5L, "이 삼각김밥은 굿굿", false);
+        final var reviews = List.of(review1_1, review1_2, review1_3, review1_4, review2_1, review2_2,
+                review3_1, review3_2, review3_3);
+        복수_리뷰_추가_요청(reviews);
+
+        // when
+        final var response = 상품_랭킹_조회_요청();
+
+        // then
+        STATUS_CODE를_검증한다(response, 정상_처리);
+        상품_랭킹_조회_결과를_검증한다(response, List.of(product2, product3, product1));
+    }
+
     private Long 카테고리_추가_요청(final Category category) {
         return categoryRepository.save(category).getId();
     }
@@ -486,4 +521,15 @@ class 리뷰수_기준_내림차순으로_카테고리별_상품_목록_조회 {
                 .ignoringFields("id")
                 .isEqualTo(expected);
     }
+
+    private void 상품_랭킹_조회_결과를_검증한다(final ExtractableResponse<Response> response, final List<Product> products) {
+        final var expected = products.stream()
+                .map(RankingProductDto::toDto)
+                .collect(Collectors.toList());
+        final var actual = response.jsonPath()
+                .getList("products", RankingProductDto.class);
+
+        assertThat(actual).usingRecursiveComparison()
+                .isEqualTo(expected);
+    }
 }

backend/src/test/java/com/funeat/acceptance/product/ProductSteps.java

@@ -48,4 +48,12 @@ public class ProductSteps {
                 .then()
                 .extract();
     }
+
+    public static ExtractableResponse<Response> 상품_랭킹_조회_요청() {
+        return given()
+                .when()
+                .get("/api/ranks/products")
+                .then()
+                .extract();
+    }
 }

backend/src/test/java/com/funeat/product/application/ProductServiceTest.java

@@ -0,0 +1,78 @@
+package com.funeat.product.application;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import com.funeat.common.DataClearExtension;
+import com.funeat.member.domain.Member;
+import com.funeat.member.persistence.MemberRepository;
+import com.funeat.product.domain.Product;
+import com.funeat.product.dto.RankingProductDto;
+import com.funeat.product.dto.RankingProductsResponse;
+import com.funeat.product.persistence.ProductRepository;
+import com.funeat.review.domain.Review;
+import com.funeat.review.persistence.ReviewRepository;
+import java.util.List;
+import org.junit.jupiter.api.DisplayNameGeneration;
+import org.junit.jupiter.api.DisplayNameGenerator.ReplaceUnderscores;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.transaction.annotation.Transactional;
+
+@Transactional
+@SpringBootTest
+@ExtendWith(DataClearExtension.class)
+@SuppressWarnings("NonAsciiCharacters")
+@DisplayNameGeneration(ReplaceUnderscores.class)
+class ProductServiceTest {
+
+    @Autowired
+    private ProductService productService;
+
+    @Autowired
+    private ProductRepository productRepository;
+
+    @Autowired
+    private MemberRepository memberRepository;
+
+    @Autowired
+    private ReviewRepository reviewRepository;
+
+    @Test
+    void 전체_상품_중_랭킹이_높은_상위_3개_상품을_구할_수_있다() {
+        // given
+        final var product1 = new Product("삼각김밥1", 1000L, "image.png", "맛있는 삼각김밥1", 3.5, null);
+        final var product2 = new Product("삼각김밥2", 2000L, "image.png", "맛있는 삼각김밥2", 4.0, null);
+        final var product3 = new Product("삼각김밥3", 1500L, "image.png", "맛있는 삼각김밥3", 5.0, null);
+        final var product4 = new Product("삼각김밥4", 1200L, "image.png", "맛있는 삼각김밥4", 2.0, null);
+        productRepository.saveAll(List.of(product1, product2, product3, product4));
+
+        final var member = memberRepository.save(new Member("test", "image.png", "1"));
+        final var review1_1 = new Review(member, product1, "review.png", 5L, "이 삼각김밥은 최고!!", true);
+        final var review1_2 = new Review(member, product1, "review.png", 3L, "이 삼각김밥은 맛있다", true);
+        final var review1_3 = new Review(member, product1, "review.png", 3L, "이 삼각김밥은 맛있다", true);
+        final var review1_4 = new Review(member, product1, "review.png", 3L, "이 삼각김밥은 맛있다", true);
+        final var review2_1 = new Review(member, product2, "review.png", 4L, "이 삼각김밥은 맛있다", false);
+        final var review2_2 = new Review(member, product2, "review.png", 4L, "이 삼각김밥은 맛있다", false);
+        final var review3_1 = new Review(member, product3, "review.png", 5L, "이 삼각김밥은 굿굿", false);
+        final var review4_1 = new Review(member, product4, "review.png", 2L, "이 삼각김밥은 좀 맛없다", false);
+        final var review4_2 = new Review(member, product4, "review.png", 2L, "이 삼각김밥은 좀 맛없다", false);
+        final var review4_3 = new Review(member, product4, "review.png", 2L, "이 삼각김밥은 좀 맛없다", false);
+        reviewRepository.saveAll(
+                List.of(review1_1, review1_2, review1_3, review1_4, review2_1, review2_2, review3_1, review4_1,
+                        review4_2, review4_3)
+        );
+
+        // when
+        final var actual = productService.getTop3Products();
+
+        // then
+        final var expected = RankingProductsResponse.toResponse(
+                List.of(RankingProductDto.toDto(product3), RankingProductDto.toDto(product2),
+                        RankingProductDto.toDto(product1))
+        );
+        assertThat(actual).usingRecursiveComparison()
+                .isEqualTo(expected);
+    }
+}