feat: AI 이미지 생성권 남은 횟수 조회 API 구현 (#157)

src/main/java/hanium/modic/backend/domain/ai/service/AiImagePermissionService.java

@@ -13,6 +13,7 @@
 import hanium.modic.backend.domain.post.entity.PostEntity;
 import hanium.modic.backend.domain.post.repository.PostEntityRepository;
 import hanium.modic.backend.domain.user.service.UserCoinService;
+import hanium.modic.backend.web.ai.dto.response.GetRemainingGenerationsResponse;
 import lombok.RequiredArgsConstructor;
 
 @Service
@@ -71,4 +72,18 @@ public void consumeRemainingGenerations(final Long userId, final Long postId) {
 			throw new AppException(AI_IMAGE_PERMISSION_FAIL_EXCEPTION);
 		}
 	}
+
+	// 유저의 특정 포스트에 대한 남은 생성 횟수 조회
+	@Transactional(readOnly = true)
+	public GetRemainingGenerationsResponse getRemainingGenerations(final Long userId, final Long postId) {
+		AiImagePermissionEntity aiImagePermission = aiImagePermissionRepository.findByUserIdAndPostId(userId,
+				postId)
+			.orElseThrow(() -> new AppException(AI_IMAGE_PERMISSION_NOT_FOUND));
+
+		return new GetRemainingGenerationsResponse(
+			aiImagePermission.getId(),
+			aiImagePermission.getRemainingGenerations()
+		);
+
+	}
 }

src/main/java/hanium/modic/backend/web/ai/controller/AiImagePermissionController.java

@@ -2,15 +2,18 @@
 
 import org.springframework.http.ResponseEntity;
 import org.springframework.validation.annotation.Validated;
+import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.RestController;
 
 import hanium.modic.backend.common.annotation.user.CurrentUser;
 import hanium.modic.backend.domain.ai.service.AiImagePermissionService;
 import hanium.modic.backend.domain.user.entity.UserEntity;
 import hanium.modic.backend.web.ai.dto.request.BuyAiImagePermissionRequest;
+import hanium.modic.backend.web.ai.dto.response.GetRemainingGenerationsResponse;
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.responses.ApiResponse;
 import io.swagger.v3.oas.annotations.tags.Tag;
@@ -67,4 +70,22 @@ public ResponseEntity<Void> buyAiImagePermissionWithTicket(
 
 		return ResponseEntity.ok().build();
 	}
+
+	@Operation(
+		summary = "AI 이미지 생성권 남은 횟수 조회",
+		description = "특정 포스트에 대한 사용자의 AI 이미지 생성권 남은 횟수를 조회합니다.(구매한 이력이 없으면 AI-004 에러)",
+		responses = {
+			@ApiResponse(responseCode = "404", description = "해당 유저를 찾을 수 없습니다.[U-002]"),
+			@ApiResponse(responseCode = "404", description = "AI 이미지 생성권을 구매한 이력이 없습니다.[AI-004]")
+		}
+	)
+	@GetMapping("/remaining-generations")
+	public ResponseEntity<GetRemainingGenerationsResponse> getRemainingGenerations(
+		@CurrentUser UserEntity user,
+		@RequestParam Long postId
+	) {
+		GetRemainingGenerationsResponse response = aiImagePermissionService.getRemainingGenerations(user.getId(), postId);
+
+		return ResponseEntity.ok(response);
+	}
 }

src/main/java/hanium/modic/backend/web/ai/dto/response/GetRemainingGenerationsResponse.java

@@ -0,0 +1,7 @@
+package hanium.modic.backend.web.ai.dto.response;
+
+public record GetRemainingGenerationsResponse(
+	Long aiImagePermissionId,
+	Integer remainingGenerations
+) {
+}

src/test/java/hanium/modic/backend/web/ai/controller/AiImagePermissionControllerIntegrationTest.java

@@ -268,4 +268,65 @@ void buyAiImagePermission_InvalidRequest_NullPostId() throws Exception {
 		// then
 		resultActions.andExpect(status().isBadRequest());
 	}
+
+	@Test
+	@WithCustomUser(email = "test@test.com")
+	@DisplayName("AI 이미지 생성권 남은 횟수 조회 - 성공")
+	void getRemainingGenerations_Success() throws Exception {
+		// given
+		UserEntity user = getCurrentUserWithCoin(0L);
+		PostEntity post = createTestPost(user);
+
+		// AI 이미지 권한 생성
+		AiImagePermissionEntity permission = AiImagePermissionEntity.builder()
+			.userId(user.getId())
+			.postId(post.getId())
+			.remainingGenerations(15)
+			.build();
+		aiImagePermissionRepository.save(permission);
+
+		// when
+		ResultActions resultActions = mockMvc.perform(get("/api/ai/image-permissions/remaining-generations")
+			.param("postId", post.getId().toString()));
+
+		// then
+		resultActions.andExpect(status().isOk())
+			.andExpect(jsonPath("$.aiImagePermissionId").value(permission.getId()))
+			.andExpect(jsonPath("$.remainingGenerations").value(15));
+	}
+
+	@Test
+	@WithCustomUser(email = "test@test.com")
+	@DisplayName("AI 이미지 생성권 남은 횟수 조회 - 구매한 이력이 없음")
+	void getRemainingGenerations_PermissionNotFound() throws Exception {
+		// given
+		UserEntity user = getCurrentUserWithCoin(0L);
+		PostEntity post = createTestPost(user);
+
+		// when
+		ResultActions resultActions = mockMvc.perform(get("/api/ai/image-permissions/remaining-generations")
+			.param("postId", post.getId().toString()));
+
+		// then
+		resultActions.andExpect(status().isNotFound())
+			.andExpect(jsonPath("$.code").value(AI_IMAGE_PERMISSION_NOT_FOUND.getCode()))
+			.andExpect(jsonPath("$.message").value(AI_IMAGE_PERMISSION_NOT_FOUND.getMessage()));
+	}
+
+	@Test
+	@WithCustomUser(email = "test@test.com")
+	@DisplayName("AI 이미지 생성권 남은 횟수 조회 - 존재하지 않는 포스트")
+	void getRemainingGenerations_PostNotExist() throws Exception {
+		// given
+		Long nonExistentPostId = 9999L;
+
+		// when
+		ResultActions resultActions = mockMvc.perform(get("/api/ai/image-permissions/remaining-generations")
+			.param("postId", nonExistentPostId.toString()));
+
+		// then
+		resultActions.andExpect(status().isNotFound())
+			.andExpect(jsonPath("$.code").value(AI_IMAGE_PERMISSION_NOT_FOUND.getCode()))
+			.andExpect(jsonPath("$.message").value(AI_IMAGE_PERMISSION_NOT_FOUND.getMessage()));
+	}
 }