[feat] 방 게임 시작 구현

backend/src/main/java/io/f1/backend/domain/game/app/RoomService.java

@@ -10,12 +10,14 @@
 import static io.f1.backend.global.util.SecurityUtils.getCurrentUserId;
 import static io.f1.backend.global.util.SecurityUtils.getCurrentUserNickname;
 
+import io.f1.backend.domain.game.dto.GameStartData;
 import io.f1.backend.domain.game.dto.RoomEventType;
 import io.f1.backend.domain.game.dto.RoomExitData;
 import io.f1.backend.domain.game.dto.RoomInitialData;
 import io.f1.backend.domain.game.dto.request.RoomCreateRequest;
 import io.f1.backend.domain.game.dto.request.RoomValidationRequest;
 import io.f1.backend.domain.game.dto.response.GameSettingResponse;
+import io.f1.backend.domain.game.dto.response.GameStartResponse;
 import io.f1.backend.domain.game.dto.response.PlayerListResponse;
 import io.f1.backend.domain.game.dto.response.RoomCreateResponse;
 import io.f1.backend.domain.game.dto.response.RoomListResponse;
@@ -190,4 +192,52 @@ private static String getDestination(Long roomId) {
     private static Player createPlayer() {
         return new Player(getCurrentUserId(), getCurrentUserNickname());
     }
+
+    private Integer checkGameSetting(Room room, Long quizId) {
+
+        GameSetting gameSetting = room.getGameSetting();
+
+        Long roomQuizId = gameSetting.getQuizId();
+
+        if (!roomQuizId.equals(quizId)) {
+            throw new IllegalArgumentException("E409002 : 게임 설정이 다릅니다. (게임을 시작할 수 없습니다.)");
+        }
+
+        return gameSetting.getRound();
+    }
+
+    public GameStartData gameStart(Long roomId, Long quizId) {
+
+        Room room =
+                roomRepository
+                        .findRoom(roomId)
+                        .orElseThrow(() -> new IllegalArgumentException("404 존재하지 않는 방입니다."));
+
+        if (!validateReadyStatus(room)) {
+            throw new IllegalArgumentException("E403004 : 레디 상태가 아닙니다.");
+        }
+
+        // 방의 gameSetting에 설정된 퀴즈랑 요청 퀴즈랑 같은지 체크 후 GameSetting에서 라운드 가져오기
+        Integer round = checkGameSetting(room, quizId);
+
+        // 라운드 수만큼 랜덤 Question 추출
+        GameStartResponse questions = quizService.getRandomQuestionsWithoutAnswer(quizId, round);
+
+        // 방 정보 게임 중으로 변경
+        room.updateRoomState(RoomState.PLAYING);
+
+        return new GameStartData(getDestination(roomId), questions);
+    }
+
+    private boolean validateReadyStatus(Room room) {
+
+        Map<String, Player> playerSessionMap = room.getPlayerSessionMap();
+
+        for (Player player : playerSessionMap.values()) {
+            if (!player.isReady()) {
+                return false;
+            }
+        }
+        return true;
+    }
 }

backend/src/main/java/io/f1/backend/domain/game/dto/GameStartData.java

@@ -0,0 +1,5 @@
+package io.f1.backend.domain.game.dto;
+
+import io.f1.backend.domain.game.dto.response.GameStartResponse;
+
+public record GameStartData(String destination, GameStartResponse gameStartResponse) {}

backend/src/main/java/io/f1/backend/domain/game/dto/MessageType.java

@@ -5,4 +5,5 @@ public enum MessageType {
     GAME_SETTING,
     PLAYER_LIST,
     SYSTEM_NOTICE,
+    GAME_START,
 }

backend/src/main/java/io/f1/backend/domain/game/dto/request/GameStartRequest.java

@@ -0,0 +1,3 @@
+package io.f1.backend.domain.game.dto.request;
+
+public record GameStartRequest(Long quizId) {}

backend/src/main/java/io/f1/backend/domain/game/dto/response/GameStartResponse.java

@@ -0,0 +1,7 @@
+package io.f1.backend.domain.game.dto.response;
+
+import io.f1.backend.domain.quiz.dto.GameQuestionResponse;
+
+import java.util.List;
+
+public record GameStartResponse(List<GameQuestionResponse> questions) {}

backend/src/main/java/io/f1/backend/domain/game/model/Room.java

@@ -39,4 +39,8 @@ public Room(Long id, RoomSetting roomSetting, GameSetting gameSetting, Player ho
     public void updateHost(Player nextHost) {
         this.host = nextHost;
     }
+
+    public void updateRoomState(RoomState newState) {
+        this.state = newState;
+    }
 }

backend/src/main/java/io/f1/backend/domain/game/websocket/GameSocketController.java

@@ -1,9 +1,12 @@
 package io.f1.backend.domain.game.websocket;
 
 import io.f1.backend.domain.game.app.RoomService;
+import io.f1.backend.domain.game.dto.GameStartData;
 import io.f1.backend.domain.game.dto.MessageType;
 import io.f1.backend.domain.game.dto.RoomExitData;
 import io.f1.backend.domain.game.dto.RoomInitialData;
+import io.f1.backend.domain.game.dto.request.GameStartRequest;
+import io.f1.backend.domain.quiz.app.QuizService;
 
 import lombok.RequiredArgsConstructor;
 
@@ -19,6 +22,7 @@ public class GameSocketController {
 
     private final MessageSender messageSender;
     private final RoomService roomService;
+    private final QuizService quizService;
 
     @MessageMapping("/room/enter/{roomId}")
     public void roomEnter(@DestinationVariable Long roomId, Message<?> message) {
@@ -55,6 +59,18 @@ public void exitRoom(@DestinationVariable Long roomId, Message<?> message) {
         }
     }
 
+    @MessageMapping("/room/start/{roomId}")
+    public void gameStart(@DestinationVariable Long roomId, Message<GameStartRequest> message) {
+
+        Long quizId = message.getPayload().quizId();
+
+        GameStartData gameStartData = roomService.gameStart(roomId, quizId);
+
+        String destination = gameStartData.destination();
+
+        messageSender.send(destination, MessageType.GAME_START, gameStartData.gameStartResponse());
+    }
+
     private static String getSessionId(Message<?> message) {
         StompHeaderAccessor accessor = StompHeaderAccessor.wrap(message);
         return accessor.getSessionId();

backend/src/main/java/io/f1/backend/domain/quiz/app/QuizService.java

@@ -4,8 +4,10 @@
 
 import static java.nio.file.Files.deleteIfExists;
 
+import io.f1.backend.domain.game.dto.response.GameStartResponse;
 import io.f1.backend.domain.question.app.QuestionService;
 import io.f1.backend.domain.question.dto.QuestionRequest;
+import io.f1.backend.domain.question.entity.Question;
 import io.f1.backend.domain.quiz.dao.QuizRepository;
 import io.f1.backend.domain.quiz.dto.QuizCreateRequest;
 import io.f1.backend.domain.quiz.dto.QuizCreateResponse;
@@ -205,6 +207,7 @@ public Long getQuizMinId() {
         return quizRepository.getQuizMinId();
     }
 
+    @Transactional(readOnly = true)
     public QuizQuestionListResponse getQuizWithQuestions(Long quizId) {
         Quiz quiz =
                 quizRepository
@@ -213,4 +216,15 @@ public QuizQuestionListResponse getQuizWithQuestions(Long quizId) {
 
         return quizToQuizQuestionListResponse(quiz);
     }
+
+    @Transactional(readOnly = true)
+    public GameStartResponse getRandomQuestionsWithoutAnswer(Long quizId, Integer round) {
+        quizRepository
+                .findById(quizId)
+                .orElseThrow(() -> new NoSuchElementException("존재하지 않는 퀴즈입니다."));
+
+        List<Question> randomQuestions = quizRepository.findRandQuestionsByQuizId(quizId, round);
+
+        return toGameStartResponse(randomQuestions);
+    }
 }

backend/src/main/java/io/f1/backend/domain/quiz/dao/QuizRepository.java

@@ -1,12 +1,15 @@
 package io.f1.backend.domain.quiz.dao;
 
+import io.f1.backend.domain.question.entity.Question;
 import io.f1.backend.domain.quiz.entity.Quiz;
 
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.data.jpa.repository.Query;
 
+import java.util.List;
+
 public interface QuizRepository extends JpaRepository<Quiz, Long> {
 
     Page<Quiz> findQuizzesByTitleContaining(String title, Pageable pageable);
@@ -15,4 +18,9 @@ public interface QuizRepository extends JpaRepository<Quiz, Long> {
 
     @Query("SELECT MIN(q.id) FROM Quiz q")
     Long getQuizMinId();
+
+    @Query(
+            value = "SELECT * FROM question WHERE quiz_id = :quizId ORDER BY RAND() LIMIT :round",
+            nativeQuery = true)
+    List<Question> findRandQuestionsByQuizId(Long quizId, Integer round);
 }

backend/src/main/java/io/f1/backend/domain/quiz/dto/GameQuestionResponse.java

@@ -0,0 +1,3 @@
+package io.f1.backend.domain.quiz.dto;
+
+public record GameQuestionResponse(Long id, String question) {}

backend/src/main/java/io/f1/backend/domain/quiz/mapper/QuizMapper.java

@@ -1,7 +1,9 @@
 package io.f1.backend.domain.quiz.mapper;
 
+import io.f1.backend.domain.game.dto.response.GameStartResponse;
 import io.f1.backend.domain.question.dto.QuestionResponse;
 import io.f1.backend.domain.question.entity.Question;
+import io.f1.backend.domain.quiz.dto.GameQuestionResponse;
 import io.f1.backend.domain.quiz.dto.QuizCreateRequest;
 import io.f1.backend.domain.quiz.dto.QuizCreateResponse;
 import io.f1.backend.domain.quiz.dto.QuizListPageResponse;
@@ -83,4 +85,16 @@ public static QuizQuestionListResponse quizToQuizQuestionListResponse(Quiz quiz)
                 quiz.getQuestions().size(),
                 questionsToQuestionResponses(quiz.getQuestions()));
     }
+
+    public static List<GameQuestionResponse> toGameQuestionResponseList(List<Question> questions) {
+        return questions.stream().map(QuizMapper::toGameQuestionResponse).toList();
+    }
+
+    public static GameQuestionResponse toGameQuestionResponse(Question question) {
+        return new GameQuestionResponse(question.getId(), question.getTextQuestion().getContent());
+    }
+
+    public static GameStartResponse toGameStartResponse(List<Question> questions) {
+        return new GameStartResponse(toGameQuestionResponseList(questions));
+    }
 }