feat(PlaylistController): 곡 상세 정보 조회용 API 추가

Author: gzhan0226

main-server/src/main/java/com/example/demo/domain/playlist/controller/PlaylistController.java

@@ -32,8 +32,28 @@ public class PlaylistController {
     private final PlaylistService playlistService;
 
     @Operation(
-            summary = "플레이리스트 상세 조회 + 재생 기록 저장",
-            description = "플레이리스트 상세를 조회하면서 동시에 재생 기록을 저장합니다."
+            summary = "플레이리스트 재생",
+            description = "플레이리스트 상세 정보를 조회하면서 동시에 재생 기록을 저장합니다."
+    )
+    @ApiResponse(
+            responseCode = "200",
+            description = "플레이리스트 상세 정보",
+            content = @Content(schema = @Schema(implementation = MainPlaylistDetailResponse.class))
+    )
+    @PostMapping("/{playlistId}/")
+    public ResponseEntity<MainPlaylistDetailResponse> playPlaylist(
+            @Parameter(description = "플레이리스트 ID", example = "101")
+            @PathVariable Long playlistId,
+            @Parameter(hidden = true)
+            @AuthenticationPrincipal CustomUserDetails user
+    ) {
+        MainPlaylistDetailResponse response = playlistService.playPlaylist(playlistId, user.getId());
+        return ResponseEntity.ok(response);
+    }
+
+    @Operation(
+            summary = "플레이리스트 상세 정보 조회",
+            description = "플레이리스트 상세 정보를 조회합니다"
     )
     @ApiResponse(
             responseCode = "200",

main-server/src/main/java/com/example/demo/domain/playlist/service/PlaylistService.java

@@ -9,6 +9,8 @@
 
 public interface PlaylistService {
 
+    MainPlaylistDetailResponse playPlaylist(Long playlistId, String userId);
+
     MainPlaylistDetailResponse getPlaylistDetail(Long playlistId, String userId);
 
     PlaylistWithSongsResponse saveFinalPlaylistWithSongsAndCd(String usersId, PlaylistCreateRequest request, List<CdItemRequest> cdItemRequestList);

main-server/src/main/java/com/example/demo/domain/playlist/service/PlaylistServiceImpl.java

@@ -41,7 +41,7 @@ public class PlaylistServiceImpl implements PlaylistService {
 
     @Override
     @Transactional
-    public MainPlaylistDetailResponse getPlaylistDetail(Long playlistId, String userId) {
+    public MainPlaylistDetailResponse playPlaylist(Long playlistId, String userId) {
         Playlist playlist = playlistRepository.findById(playlistId)
                 .filter(Playlist::isPublic)
                 .orElseThrow(() -> new PlaylistException("플레이리스트가 없거나 비공개 상태입니다.", PlaylistErrorCode.PLAYLIST_NOT_FOUND));
@@ -59,6 +59,23 @@ public MainPlaylistDetailResponse getPlaylistDetail(Long playlistId, String user
         return MainPlaylistDetailResponse.from(playlist, songDtos, cdResponse);
     }
 
+    @Override
+    @Transactional
+    public MainPlaylistDetailResponse getPlaylistDetail(Long playlistId, String userId) {
+        Playlist playlist = playlistRepository.findById(playlistId)
+                .filter(Playlist::isPublic)
+                .orElseThrow(() -> new PlaylistException("플레이리스트가 없거나 비공개 상태입니다.", PlaylistErrorCode.PLAYLIST_NOT_FOUND));
+
+        Users user = userRepository.findById(userId)
+                .orElseThrow(() -> new UserException(UserErrorCode.USER_NOT_FOUND));
+
+        List<Song> songs = songRepository.findSongsByPlaylistId(playlist.getId());
+        List<SongDto> songDtos = songs.stream().map(SongDto::from).toList();
+
+        var cdResponse = cdService.getOnlyCdByPlaylistId(playlistId);
+        return MainPlaylistDetailResponse.from(playlist, songDtos, cdResponse);
+    }
+
     @Override
     @Transactional
     public PlaylistWithSongsResponse saveFinalPlaylistWithSongsAndCd(String usersId, PlaylistCreateRequest request,