feat: AI 코스 후보 추천 기능 구현

src/main/java/com/daytodo/domain/course/controller/CourseController.java

@@ -3,6 +3,7 @@
 import com.daytodo.domain.course.dto.CourseRequest;
 import com.daytodo.domain.course.dto.CourseResponse;
 import com.daytodo.domain.course.service.CourseService;
+import com.daytodo.domain.course.service.CourseAiRecommendationService;
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.tags.Tag;
 import jakarta.validation.Valid;
@@ -21,6 +22,7 @@
 @RequiredArgsConstructor
 public class CourseController {
     private final CourseService courseService;
+    private final CourseAiRecommendationService courseAiRecommendationService;
 
     @Operation(summary = "홈 및 생성한 코스 목록 통합 조회")
     @GetMapping
@@ -53,6 +55,15 @@ public CourseResponse.Created createCourse(
         return courseService.createCourse(userId, request);
     }
 
+    @Operation(summary = "AI 추천 코스 2종 조회")
+    @PostMapping("/ai-recommendations")
+    public CourseResponse.AiRecommendations getAiRecommendations(
+            @AuthenticationPrincipal Long userId,
+            @Valid @RequestBody CourseRequest.AiRecommendation request
+    ) {
+        return courseAiRecommendationService.recommend(request);
+    }
+
     @Operation(summary = "초대코드로 코스 참가")
     @PostMapping("/join")
     public CourseResponse.Joined joinCourse(

src/main/java/com/daytodo/domain/course/dto/CourseRequest.java

@@ -44,6 +44,19 @@ public record Join(
     ) {
     }
 
+    public record AiRecommendation(
+            @NotNull(message = "지역은 필수입니다.") Long regionId,
+            @NotNull(message = "최소 금액은 필수입니다.")
+            @PositiveOrZero(message = "최소 금액은 0 이상이어야 합니다.") Integer minPrice,
+            @NotNull(message = "최대 금액은 필수입니다.")
+            @PositiveOrZero(message = "최대 금액은 0 이상이어야 합니다.") Integer maxPrice
+    ) {
+        @AssertTrue(message = "최대 금액은 최소 금액보다 작을 수 없습니다.")
+        public boolean isValidPriceRange() {
+            return minPrice == null || maxPrice == null || maxPrice >= minPrice;
+        }
+    }
+
     // ==============================================================================
 
     public record Setting(

src/main/java/com/daytodo/domain/course/dto/CourseResponse.java

@@ -77,6 +77,47 @@ public record Created(Long courseId, String inviteCode, LocalDateTime inviteCode
     public record Joined(Long courseId, String courseName) {
     }
 
+    public record AiRecommendations(
+            boolean success,
+            String code,
+            String message,
+            List<AiRecommendationCourse> result
+    ) {
+        public AiRecommendations {
+            result = List.copyOf(result);
+        }
+    }
+
+    public record AiRecommendationCourse(
+            String courseName,
+            int estimatedTotalMinPrice,
+            int estimatedTotalMaxPrice,
+            List<AiRecommendationPlace> places
+    ) {
+        public AiRecommendationCourse {
+            places = List.copyOf(places);
+        }
+    }
+
+    public record AiRecommendationPlace(
+            int recommendationOrder,
+            Long placeId,
+            String naverPlaceId,
+            String placeName,
+            String category,
+            String address,
+            String roadAddress,
+            double latitude,
+            double longitude,
+            String description,
+            String imageUrl,
+            int minPrice,
+            int maxPrice,
+            double priceConfidence,
+            String priceReason
+    ) {
+    }
+
 // ==============================================================================
 
     public record Setting(

src/main/java/com/daytodo/domain/course/exception/code/CourseErrorCode.java

@@ -35,7 +35,8 @@ public enum CourseErrorCode implements BaseErrorCode {
     RECOMMENDATION_ALREADY_LIKED(HttpStatus.CONFLICT, "RECOMMENDATION_ALREADY_LIKED", "이미 좋아요를 누른 추천입니다."),
     DUPLICATE_PLACE(HttpStatus.CONFLICT, "DUPLICATE_PLACE", "이미 코스에 추가된 장소입니다."),
     PLACE_NOT_FOUND(HttpStatus.NOT_FOUND, "PLACE_NOT_FOUND", "장소를 찾을 수 없습니다."),
-    DUPLICATE_RECOMMENDATION(HttpStatus.CONFLICT, "DUPLICATE_RECOMMENDATION", "이미 추천된 장소입니다.");
+    DUPLICATE_RECOMMENDATION(HttpStatus.CONFLICT, "DUPLICATE_RECOMMENDATION", "이미 추천된 장소입니다."),
+    COURSE_RECOMMENDATION_FAILED(HttpStatus.CONFLICT, "COURSE_RECOMMENDATION_FAILED", "추천 코스를 생성할 수 없습니다.");
 
     private final HttpStatus status;
     private final String code;

src/main/java/com/daytodo/domain/place/entity/Place.java

@@ -49,4 +49,20 @@ public class Place extends BaseEntity {
 
     @Column (name = "image_url", length = 500)
     private String imageUrl;
+
+    public Place(Region region, String naverPlaceId, String placeName, String category,
+                 String address, String roadAddress, double latitude, double longitude,
+                 String phone, String description, String imageUrl) {
+        this.region = region;
+        this.naverPlaceId = naverPlaceId;
+        this.placeName = placeName;
+        this.category = category;
+        this.address = address;
+        this.roadAddress = roadAddress;
+        this.latitude = latitude;
+        this.longitude = longitude;
+        this.phone = phone;
+        this.description = description;
+        this.imageUrl = imageUrl;
+    }
 }

src/main/java/com/daytodo/domain/place/entity/PlacePriceEstimate.java

@@ -39,4 +39,15 @@ public class PlacePriceEstimate {
     // 추론 근거
     @Column (name = "reason", length = 500)
     private String reason;
+
+    public PlacePriceEstimate(Place place, int minPrice, int maxPrice, double confidence, String reason) {
+        if (maxPrice < minPrice) {
+            throw new IllegalArgumentException("최대 가격은 최소 가격보다 작을 수 없습니다.");
+        }
+        this.place = place;
+        this.minPrice = minPrice;
+        this.maxPrice = maxPrice;
+        this.confidence = confidence;
+        this.reason = reason;
+    }
 }

src/main/java/com/daytodo/domain/place/repository/PlaceRepository.java

@@ -3,8 +3,11 @@
 import com.daytodo.domain.place.entity.Place;
 import org.springframework.data.jpa.repository.JpaRepository;
 
+import java.util.Optional;
+
 /**
  * 이미 존재한다면 이 파일은 만들지 않아도 됩니다 (findAllById는 JpaRepository 기본 제공 메서드).
  */
 public interface PlaceRepository extends JpaRepository<Place, Long> {
-}
+    Optional<Place> findByNaverPlaceId(String naverPlaceId);
+}

src/test/java/com/daytodo/domain/course/service/CourseServiceTest.java

@@ -21,6 +21,10 @@
 import com.daytodo.domain.user.entity.User;
 import com.daytodo.domain.user.enums.LoginType;
 import com.daytodo.domain.user.service.UserService;
+import com.daytodo.domain.place.repository.PlaceRecommendationRepository;
+import com.daytodo.domain.place.repository.RecommendationLikeRepository;
+import com.daytodo.domain.place.repository.PlaceRepository;
+import com.daytodo.domain.place.repository.RecommendationCommentRepository;
 import com.daytodo.global.apiPayload.exception.ProjectException;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -62,6 +66,10 @@ class CourseServiceTest {
     @Mock InviteCodeRepository inviteCodeRepository;
     @Mock RegionRepository regionRepository;
     @Mock UserService userService;
+    @Mock PlaceRecommendationRepository placeRecommendationRepository;
+    @Mock RecommendationLikeRepository recommendationLikeRepository;
+    @Mock PlaceRepository placeRepository;
+    @Mock RecommendationCommentRepository recommendationCommentRepository;
 
     CourseService courseService;
     User user;
@@ -76,6 +84,10 @@ void setUp() {
                 inviteCodeRepository,
                 regionRepository,
                 userService,
+                placeRecommendationRepository,
+                recommendationLikeRepository,
+                placeRepository,
+                recommendationCommentRepository,
                 CLOCK
         );
         user = new User("user@example.com", "password", "user", null, LoginType.LOCAL);

src/test/java/com/daytodo/global/config/TargetApiSecurityTest.java

@@ -3,6 +3,7 @@
 import com.daytodo.domain.course.controller.CourseController;
 import com.daytodo.domain.course.dto.CourseResponse;
 import com.daytodo.domain.course.service.CourseService;
+import com.daytodo.domain.course.service.CourseAiRecommendationService;
 import com.daytodo.domain.user.controller.UserController;
 import com.daytodo.domain.user.dto.UserResponse;
 import com.daytodo.domain.user.service.FeedbackService;
@@ -56,6 +57,7 @@ class TargetApiSecurityTest {
     @MockitoBean FeedbackService feedbackService;
     @MockitoBean PolicyService policyService;
     @MockitoBean CourseService courseService;
+    @MockitoBean CourseAiRecommendationService courseAiRecommendationService;
     @MockitoBean JpaMetamodelMappingContext jpaMetamodelMappingContext;
 
     @Test
@@ -87,6 +89,15 @@ void targetCourseApiRejectsRequestWithoutJwt() throws Exception {
                 .andExpect(status().isUnauthorized());
     }
 
+    @Test
+    void aiRecommendationApiRejectsRequestWithoutJwt() throws Exception {
+        mockMvc.perform(post("/courses/ai-recommendations")
+                        .contentType("application/json")
+                        .content("{\"regionId\":1,\"minPrice\":10000,\"maxPrice\":30000}"))
+                .andExpect(status().isUnauthorized())
+                .andExpect(jsonPath("$.code").value("UNAUTHORIZED"));
+    }
+
     @Test
     void calendarUsesJwtPrincipal() throws Exception {
         when(courseService.getCalendar(1L, 2026, 7))