feat: 상품 좋아요 및 좋아요 취소 기능 구현

Author: codrin2

src/main/kotlin/com/dh/baro/product/application/ProductFacade.kt

@@ -5,6 +5,7 @@ import com.dh.baro.product.application.dto.ProductDetailBundle
 import com.dh.baro.product.application.dto.ProductSliceBundle
 import com.dh.baro.product.domain.service.CategoryService
 import com.dh.baro.product.domain.Product
+import com.dh.baro.product.domain.service.ProductLikeService
 import com.dh.baro.product.domain.service.ProductQueryService
 import com.dh.baro.product.domain.service.ProductService
 import org.springframework.stereotype.Service
@@ -16,6 +17,7 @@ class ProductFacade(
     private val productService: ProductService,
     private val productQueryService: ProductQueryService,
     private val categoryService: CategoryService,
+    private val productLikeService: ProductLikeService,
 ) {
 
     @Transactional
@@ -52,4 +54,14 @@ class ProductFacade(
         val stores = storeService.getStoresByIds(productSlice.content.map { it.storeId }.toSet())
         return ProductSliceBundle(productSlice, stores)
     }
+
+    @Transactional
+    fun likeProduct(userId: Long, productId: Long) {
+        productLikeService.likeProduct(userId, productId)
+    }
+
+    @Transactional
+    fun cancelProductLike(userId: Long, productId: Long) {
+        productLikeService.cancelProductLike(userId, productId)
+    }
 }

src/main/kotlin/com/dh/baro/product/domain/ProductLike.kt

@@ -1,11 +1,23 @@
 package com.dh.baro.product.domain
 
 import com.dh.baro.core.BaseTimeEntity
+import com.dh.baro.core.IdGenerator
 import jakarta.persistence.*
 
 @Entity
-@Table(name = "product_likes")
-class ProductLike(
+@Table(
+    name = "product_likes",
+    uniqueConstraints = [
+        UniqueConstraint(
+            name = "uk_product_likes_user_product",
+            columnNames = ["user_id", "product_id"]
+        )
+    ],
+    indexes = [
+        Index(name = "idx_product_likes_product_id", columnList = "product_id")
+    ]
+)
+class ProductLike private constructor(
     @Id
     @Column(name = "id")
     val id: Long,
@@ -19,4 +31,13 @@ class ProductLike(
 
     override fun getId(): Long = id
 
+    companion object {
+        fun create(userId: Long, productId: Long): ProductLike {
+            return ProductLike(
+                id = IdGenerator.generate(),
+                userId = userId,
+                productId = productId,
+            )
+        }
+    }
 }

src/main/kotlin/com/dh/baro/product/domain/repository/ProductLikeRepository.kt

@@ -0,0 +1,11 @@
+package com.dh.baro.product.domain.repository
+
+import com.dh.baro.product.domain.ProductLike
+import org.springframework.data.jpa.repository.JpaRepository
+
+interface ProductLikeRepository : JpaRepository<ProductLike, Long> {
+
+    fun existsByUserIdAndProductId(userId: Long, productId: Long): Boolean
+
+    fun deleteByUserIdAndProductId(userId: Long, productId: Long): Int
+}

src/main/kotlin/com/dh/baro/product/domain/repository/ProductRepository.kt

@@ -69,4 +69,20 @@ interface ProductRepository : JpaRepository<Product, Long> {
         @Param("cursorId") cursorId: Long?,
         pageable: Pageable,
     ): Slice<Product>
+
+    @Modifying(clearAutomatically = true, flushAutomatically = true)
+    @Query("""
+        UPDATE Product p
+        SET p.likesCount = p.likesCount + 1
+        WHERE p.id = :id
+    """)
+    fun incrementLikesCount(@Param("id") id: Long): Int
+
+    @Modifying(clearAutomatically = true, flushAutomatically = true)
+    @Query("""
+        UPDATE Product p
+        SET p.likesCount = p.likesCount - 1
+        WHERE p.id = :id AND p.likesCount > 0
+    """)
+    fun decrementLikesCount(@Param("id") id: Long): Int
 }

src/main/kotlin/com/dh/baro/product/domain/service/ProductLikeService.kt

@@ -0,0 +1,33 @@
+package com.dh.baro.product.domain.service
+
+import com.dh.baro.product.domain.ProductLike
+import com.dh.baro.product.domain.repository.ProductLikeRepository
+import com.dh.baro.product.domain.repository.ProductRepository
+import org.springframework.stereotype.Service
+import org.springframework.transaction.annotation.Transactional
+
+@Service
+class ProductLikeService(
+    private val productLikeRepository: ProductLikeRepository,
+    private val productRepository: ProductRepository,
+) {
+
+    @Transactional
+    fun likeProduct(userId: Long, productId: Long) {
+        if (productLikeRepository.existsByUserIdAndProductId(userId, productId)) {
+            return
+        }
+
+        val productLike = ProductLike.create(userId, productId)
+        productLikeRepository.save(productLike)
+        productRepository.incrementLikesCount(productId)
+    }
+
+    @Transactional
+    fun cancelProductLike(userId: Long, productId: Long) {
+        val deletedCount = productLikeRepository.deleteByUserIdAndProductId(userId, productId)
+        if (deletedCount > 0) {
+            productRepository.decrementLikesCount(productId)
+        }
+    }
+}

src/main/kotlin/com/dh/baro/product/presentation/ProductController.kt

@@ -4,6 +4,7 @@ import com.dh.baro.core.Cursor
 import com.dh.baro.core.ErrorMessage
 import com.dh.baro.core.SliceResponse
 import com.dh.baro.core.annotation.CheckAuth
+import com.dh.baro.core.annotation.CurrentUser
 import com.dh.baro.identity.domain.UserRole
 import com.dh.baro.product.application.ProductFacade
 import com.dh.baro.product.presentation.dto.*
@@ -70,6 +71,24 @@ class ProductController(
         )
     }
 
+    @PostMapping("/{productId}/likes")
+    @ResponseStatus(HttpStatus.NO_CONTENT)
+    override fun likeProduct(
+        @CurrentUser userId: Long,
+        @PathVariable productId: String,
+    ) {
+        productFacade.likeProduct(userId, productId.toLong())
+    }
+
+    @DeleteMapping("/{productId}/likes")
+    @ResponseStatus(HttpStatus.NO_CONTENT)
+    override fun cancelProductLike(
+        @CurrentUser userId: Long,
+        @PathVariable productId: String,
+    ) {
+        productFacade.cancelProductLike(userId, productId.toLong())
+    }
+
     companion object {
         private const val DEFAULT_PAGE_SIZE = "21"
     }

src/main/kotlin/com/dh/baro/product/presentation/swagger/ProductSwagger.kt

@@ -159,6 +159,48 @@ interface ProductSwagger {
         @RequestParam(defaultValue = "21") size: Int
     ): SliceResponse<ProductListItem>
 
+    /* ───────────────────────────── 상품 좋아요 ───────────────────────────── */
+    @Operation(
+        summary = "상품 좋아요",
+        description = """
+            상품에 좋아요를 추가합니다.
+            이미 좋아요한 상품의 경우 중복 요청이 무시됩니다 (멱등성 보장).
+            인증된 사용자만 사용 가능합니다.
+        """,
+        parameters = [
+            Parameter(`in` = ParameterIn.PATH, name = "productId", description = "상품 PK", example = "11", required = true)
+        ],
+        responses = [
+            ApiResponse(responseCode = "204", description = "좋아요 성공")
+        ]
+    )
+    @PostMapping("/{productId}/likes")
+    fun likeProduct(
+        userId: Long,
+        @PathVariable productId: String,
+    )
+
+    /* ───────────────────────────── 상품 좋아요 취소 ───────────────────────────── */
+    @Operation(
+        summary = "상품 좋아요 취소",
+        description = """
+            상품 좋아요를 취소합니다.
+            좋아요하지 않은 상품의 경우 요청이 무시됩니다 (멱등성 보장).
+            인증된 사용자만 사용 가능합니다.
+        """,
+        parameters = [
+            Parameter(`in` = ParameterIn.PATH, name = "productId", description = "상품 PK", example = "11", required = true)
+        ],
+        responses = [
+            ApiResponse(responseCode = "204", description = "좋아요 취소 성공")
+        ]
+    )
+    @DeleteMapping("/{productId}/likes")
+    fun cancelProductLike(
+        userId: Long,
+        @PathVariable productId: String,
+    )
+
     /* ──────────────── 예시 DTO (Swagger 문서 전용) ──────────────── */
     @Schema(hidden = true)
     private class SlicePopularExample(