refactor: 독서태그 N+1문제를 해결합니다. (#114)

* [BOOK-175] refactor: domain - N+1문제 개선 (#54)

* [BOOK-175] refactor: infra - N+1문제 개선 (#54)

* [BOOK-175] refactor: domain,infra - 코드레빗 코드리뷰 반영(#54)

Author: minwoo1999

domain/src/main/kotlin/org/yapp/domain/readingrecord/ReadingRecordDomainService.kt

@@ -102,8 +102,36 @@ class ReadingRecordDomainService(
         sort: ReadingRecordSortType?,
         pageable: Pageable
     ): Page<ReadingRecordInfoVO> {
-        return readingRecordRepository.findReadingRecordsByDynamicCondition(userBookId, sort, pageable)
-            .map { buildReadingRecordInfoVO(it) }
+        val readingRecordPage = readingRecordRepository.findReadingRecordsByDynamicCondition(userBookId, sort, pageable)
+        if (readingRecordPage.isEmpty) {
+            return Page.empty(pageable)
+        }
+
+        val readingRecords = readingRecordPage.content
+        val readingRecordIds = readingRecords.map { it.id.value }
+
+        val readingRecordTags = readingRecordTagRepository.findByReadingRecordIdIn(readingRecordIds)
+        val tagIds = readingRecordTags.map { it.tagId.value }
+        val tagsById = tagRepository.findByIds(tagIds).associateBy { it.id.value }
+
+        val tagsByReadingRecordId = readingRecordTags
+            .groupBy { it.readingRecordId.value }
+            .mapValues { (_, tags) ->
+                tags.mapNotNull { tagsById[it.tagId.value] }
+            }
+
+        val userBook = userBookRepository.findById(userBookId)
+
+        return readingRecordPage.map { readingRecord ->
+            ReadingRecordInfoVO.newInstance(
+                readingRecord = readingRecord,
+                emotionTags = tagsByReadingRecordId[readingRecord.id.value]?.map { it.name } ?: emptyList(),
+                bookTitle = userBook?.title,
+                bookPublisher = userBook?.publisher,
+                bookCoverImageUrl = userBook?.coverImageUrl,
+                author = userBook?.author
+            )
+        }
     }
 
     fun modifyReadingRecord(

domain/src/main/kotlin/org/yapp/domain/readingrecordtag/ReadingRecordTagRepository.kt

@@ -5,6 +5,7 @@ import java.util.UUID
 interface ReadingRecordTagRepository {
     fun saveAll(readingRecordTags: List<ReadingRecordTag>): List<ReadingRecordTag>
     fun findByReadingRecordId(readingRecordId: UUID): List<ReadingRecordTag>
+    fun findByReadingRecordIdIn(readingRecordIds: List<UUID>): List<ReadingRecordTag>
     fun deleteAllByReadingRecordId(readingRecordId: UUID)
     fun countTagsByUserIdAndUserBookIdAndCategories(userId: UUID, userBookId: UUID, categories: List<String>): Map<String, Int>
 }

infra/src/main/kotlin/org/yapp/infra/readingrecordtag/repository/JpaReadingRecordTagRepository.kt

@@ -6,5 +6,6 @@ import java.util.*
 
 interface JpaReadingRecordTagRepository : JpaRepository<ReadingRecordTagEntity, UUID>, JpaReadingRecordTagQuerydslRepository {
     fun findByReadingRecordId(readingRecordId: UUID): List<ReadingRecordTagEntity>
+    fun findByReadingRecordIdIn(readingRecordIds: List<UUID>): List<ReadingRecordTagEntity>
     fun deleteAllByReadingRecordId(readingRecordId: UUID)
 }

infra/src/main/kotlin/org/yapp/infra/readingrecordtag/repository/impl/ReadingRecordTagRepositoryImpl.kt

@@ -20,7 +20,18 @@ class ReadingRecordTagRepositoryImpl(
         return jpaReadingRecordTagRepository.findByReadingRecordId(readingRecordId).map { it.toDomain() }
     }
 
-    override fun countTagsByUserIdAndUserBookIdAndCategories(userId: UUID, userBookId: UUID, categories: List<String>): Map<String, Int> {
+    override fun findByReadingRecordIdIn(readingRecordIds: List<UUID>): List<ReadingRecordTag> {
+        if (readingRecordIds.isEmpty()) return emptyList()
+        return jpaReadingRecordTagRepository
+            .findByReadingRecordIdIn(readingRecordIds)
+            .map { it.toDomain() }
+    }
+
+    override fun countTagsByUserIdAndUserBookIdAndCategories(
+        userId: UUID,
+        userBookId: UUID,
+        categories: List<String>
+    ): Map<String, Int> {
         return jpaReadingRecordTagRepository.countTagsByUserIdAndUserBookIdAndCategories(userId, userBookId, categories)
     }