feat: 인기 테마 조회 시 theme에서 JOIN으로 가져오도록 수정

src/main/kotlin/roomescape/theme/business/ThemeService.kt

@@ -9,11 +9,13 @@ import org.springframework.transaction.annotation.Transactional
 import roomescape.admin.business.AdminService
 import roomescape.common.config.next
 import roomescape.common.dto.AuditInfo
+import roomescape.common.util.DateUtils
 import roomescape.theme.exception.ThemeErrorCode
 import roomescape.theme.exception.ThemeException
 import roomescape.theme.infrastructure.persistence.ThemeEntity
 import roomescape.theme.infrastructure.persistence.ThemeRepository
 import roomescape.theme.web.*
+import java.time.LocalDate
 
 private val log: KLogger = KotlinLogging.logger {}
 
@@ -43,13 +45,18 @@ class ThemeService(
     }
 
     @Transactional(readOnly = true)
-    fun findAllInfosByIds(request: ThemeIdListRequest): ThemeInfoListResponse {
-        log.info { "[ThemeService.findThemesByIds] 예약 페이지에서의 테마 목록 조회 시작: themeIds=${request.themeIds}" }
-        val result: List<ThemeEntity> = themeRepository.findAllByIdIn(request.themeIds)
+    fun findMostReservedThemeLastWeek(count: Int): ThemeInfoListResponse {
+        log.info { "[ThemeService.findMostReservedThemeLastWeek] 인기 테마 조회 시작: count=$count" }
 
-        return result.toInfoListResponse().also {
-            log.info { "[ThemeService.findThemesByIds] ${it.themes.size} / ${request.themeIds.size} 개 테마 조회 완료" }
+        val previousWeekSunday = DateUtils.getSundayOfPreviousWeek(LocalDate.now())
+        val previousWeekSaturday = previousWeekSunday.plusDays(6)
+
+        return themeRepository.findMostReservedThemeByDateAndCount(previousWeekSunday, previousWeekSaturday, count)
+            .toListResponse()
+            .also {
+                log.info { "[ThemeService.findMostReservedThemeLastWeek] ${it.themes.size} / $count 개의 인기 테마 조회 완료" }
             }
+
     }
 
     // ========================================

src/main/kotlin/roomescape/theme/docs/ThemeApi.kt

@@ -5,8 +5,10 @@ import io.swagger.v3.oas.annotations.responses.ApiResponse
 import io.swagger.v3.oas.annotations.responses.ApiResponses
 import jakarta.validation.Valid
 import org.springframework.http.ResponseEntity
+import org.springframework.web.bind.annotation.GetMapping
 import org.springframework.web.bind.annotation.PathVariable
 import org.springframework.web.bind.annotation.RequestBody
+import org.springframework.web.bind.annotation.RequestParam
 import roomescape.admin.infrastructure.persistence.AdminType
 import roomescape.admin.infrastructure.persistence.Privilege
 import roomescape.auth.web.support.AdminOnly
@@ -50,13 +52,13 @@ interface AdminThemeAPI {
 }
 
 interface PublicThemeAPI {
-    @Public
-    @Operation(summary = "입력된 모든 ID에 대한 테마 정보 조회")
-    @ApiResponses(ApiResponse(responseCode = "200", useReturnTypeSchema = true))
-    fun findThemeInfosByIds(request: ThemeIdListRequest): ResponseEntity<CommonApiResponse<ThemeInfoListResponse>>
-
     @Public
     @Operation(summary = "입력된 테마 ID에 대한 정보 조회")
     @ApiResponses(ApiResponse(responseCode = "200", useReturnTypeSchema = true))
     fun findThemeInfoById(@PathVariable id: Long): ResponseEntity<CommonApiResponse<ThemeInfoResponse>>
+
+    @Public
+    @Operation(summary = "지난 주에 가장 많이 예약된 count 개의 테마 조회")
+    @GetMapping("/most-reserved")
+    fun findMostReservedThemeLastWeek(@RequestParam count: Int): ResponseEntity<CommonApiResponse<ThemeInfoListResponse>>
 }

src/main/kotlin/roomescape/theme/infrastructure/persistence/ThemeRepository.kt

@@ -2,6 +2,8 @@ package roomescape.theme.infrastructure.persistence
 
 import org.springframework.data.jpa.repository.JpaRepository
 import org.springframework.data.jpa.repository.Query
+import roomescape.theme.business.domain.ThemeInfo
+import java.time.LocalDate
 
 interface ThemeRepository : JpaRepository<ThemeEntity, Long> {
 
@@ -10,5 +12,32 @@ interface ThemeRepository : JpaRepository<ThemeEntity, Long> {
 
     fun existsByName(name: String): Boolean
 
-    fun findAllByIdIn(themeIds: List<Long>): List<ThemeEntity>
+    @Query(
+        value = """
+            SELECT 
+                t.id, t.name, t.description, t.difficulty, t.thumbnail_url, t.price,
+                t.min_participants, t.max_participants,
+                t.available_minutes, t.expected_minutes_from, t.expected_minutes_to
+            FROM 
+                theme t
+            JOIN (
+                SELECT 
+                    s.theme_id, count(*) as reservation_count
+                FROM
+                    schedule s
+                JOIN 
+                    reservation r ON s.id = r.schedule_id AND r.status = 'CONFIRMED'
+                WHERE 
+                    s.status = 'RESERVED'
+                    AND (s.date BETWEEN :startFrom AND :endAt)
+                GROUP BY 
+                    s.theme_id  
+                ORDER BY 
+                    reservation_count desc 
+                LIMIT :count
+            ) ranked_themes ON t.id = ranked_themes.theme_id
+        """,
+        nativeQuery = true
+    )
+    fun findMostReservedThemeByDateAndCount(startFrom: LocalDate, endAt: LocalDate, count: Int): List<ThemeInfo>
 }

src/main/kotlin/roomescape/theme/web/ThemeController.kt

@@ -1,6 +1,5 @@
 package roomescape.theme.web
 
-import jakarta.validation.Valid
 import org.springframework.http.ResponseEntity
 import org.springframework.web.bind.annotation.*
 import roomescape.common.dto.response.CommonApiResponse
@@ -12,15 +11,6 @@ import roomescape.theme.docs.PublicThemeAPI
 class ThemeController(
     private val themeService: ThemeService,
 ) : PublicThemeAPI {
-    @PostMapping("/batch")
-    override fun findThemeInfosByIds(
-        @Valid @RequestBody request: ThemeIdListRequest
-    ): ResponseEntity<CommonApiResponse<ThemeInfoListResponse>> {
-        val response = themeService.findAllInfosByIds(request)
-
-        return ResponseEntity.ok(CommonApiResponse(response))
-    }
-
     @GetMapping("/{id}")
     override fun findThemeInfoById(
         @PathVariable id: Long
@@ -29,4 +19,13 @@ class ThemeController(
 
         return ResponseEntity.ok(CommonApiResponse(response))
     }
+
+    @GetMapping("/most-reserved")
+    override fun findMostReservedThemeLastWeek(
+        @RequestParam count: Int
+    ): ResponseEntity<CommonApiResponse<ThemeInfoListResponse>> {
+        val response = themeService.findMostReservedThemeLastWeek(count)
+
+        return ResponseEntity.ok(CommonApiResponse(response))
+    }
 }

src/main/kotlin/roomescape/theme/web/ThemeDto.kt

@@ -1,6 +1,6 @@
 package roomescape.theme.web
 
-import roomescape.theme.infrastructure.persistence.Difficulty
+import roomescape.theme.business.domain.ThemeInfo
 import roomescape.theme.infrastructure.persistence.ThemeEntity
 
 data class ThemeIdListRequest(
@@ -12,7 +12,7 @@ data class ThemeInfoResponse(
     val name: String,
     val thumbnailUrl: String,
     val description: String,
-    val difficulty: Difficulty,
+    val difficulty: String,
     val price: Int,
     val minParticipants: Short,
     val maxParticipants: Short,
@@ -21,7 +21,7 @@ data class ThemeInfoResponse(
     val expectedMinutesTo: Short
 )
 
-fun ThemeEntity.toInfoResponse() = ThemeInfoResponse(
+fun ThemeInfo.toInfoResponse() = ThemeInfoResponse(
     id = this.id,
     name = this.name,
     thumbnailUrl = this.thumbnailUrl,
@@ -35,10 +35,24 @@ fun ThemeEntity.toInfoResponse() = ThemeInfoResponse(
     expectedMinutesTo = this.expectedMinutesTo
 )
 
+fun ThemeEntity.toInfoResponse() = ThemeInfoResponse(
+    id = this.id,
+    name = this.name,
+    thumbnailUrl = this.thumbnailUrl,
+    description = this.description,
+    difficulty = this.difficulty.name,
+    price = this.price,
+    minParticipants = this.minParticipants,
+    maxParticipants = this.maxParticipants,
+    availableMinutes = this.availableMinutes,
+    expectedMinutesFrom = this.expectedMinutesFrom,
+    expectedMinutesTo = this.expectedMinutesTo
+)
+
 data class ThemeInfoListResponse(
     val themes: List<ThemeInfoResponse>
 )
 
-fun List<ThemeEntity>.toInfoListResponse() = ThemeInfoListResponse(
+fun List<ThemeInfo>.toListResponse() = ThemeInfoListResponse(
     themes = this.map { it.toInfoResponse() }
 )