Implement bulk reoder (inefficient)

src/main/java/com/bivashy/backend/composer/controller/PlaylistController.java

@@ -31,4 +31,5 @@ public class PlaylistController {
             @RequestBody PlaylistCreateRequest playlist) {
         return service.createPlaylist(user.getId(), playlist);
     }
+
 }

src/main/java/com/bivashy/backend/composer/controller/TrackController.java

@@ -10,10 +10,13 @@ import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.ModelAttribute;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RestController;
 
 import com.bivashy.backend.composer.dto.track.AddLocalTrackRequest;
 import com.bivashy.backend.composer.dto.track.PlaylistTrackResponse;
+import com.bivashy.backend.composer.dto.track.TrackBulkReorderRequest;
+import com.bivashy.backend.composer.dto.track.TrackReorderAfterRequest;
 import com.bivashy.backend.composer.dto.track.TrackResponse;
 import com.bivashy.backend.composer.model.User;
 import com.bivashy.backend.composer.service.TrackService;
@@ -42,4 +45,11 @@ public class TrackController {
         List<PlaylistTrackResponse> tracks = trackService.getPlaylistTracks(user, playlistId);
         return ResponseEntity.ok(tracks);
     }
+
+    @PostMapping("/playlist/{playlistId}/bulk-reorder")
+    public void bulkReorder(@AuthenticationPrincipal User user,
+            @RequestBody TrackBulkReorderRequest request,
+            @PathVariable Long playlistId) {
+        trackService.bulkReorder(user, playlistId, request);
+    }
 }

src/main/java/com/bivashy/backend/composer/dto/track/TrackBulkReorderRequest.java

@@ -0,0 +1,6 @@
+package com.bivashy.backend.composer.dto.track;
+
+import java.util.List;
+
+public record TrackBulkReorderRequest(List<Long> trackIds) {
+}

src/main/java/com/bivashy/backend/composer/dto/track/TrackReorderAfterRequest.java

@@ -0,0 +1,4 @@
+package com.bivashy.backend.composer.dto.track;
+
+public record TrackReorderAfterRequest(long moveTrackId, long targetTrackId) {
+}

src/main/java/com/bivashy/backend/composer/service/TrackPlaylistService.java

@@ -2,7 +2,10 @@ package com.bivashy.backend.composer.service;
 
 import java.math.BigDecimal;
 import java.math.RoundingMode;
+import java.util.ArrayList;
 import java.util.List;
+import java.util.Set;
+import java.util.stream.Collectors;
 
 import org.springframework.stereotype.Service;
 
@@ -41,11 +44,9 @@ public class TrackPlaylistService {
     private void addTrack(Long playlistId, Long trackId, BigDecimal afterOrder) {
         BigDecimal newOrder;
         if (afterOrder == null) {
-            // Insert at the end
             BigDecimal maxOrder = repository.findMaxOrderByPlaylistId(playlistId);
             newOrder = findIntermediateOrder(maxOrder, null);
         } else {
-            // Insert after a specific track
             BigDecimal nextOrder = repository.findNextOrderByPlaylistIdAndOrderGreaterThan(playlistId, afterOrder);
             newOrder = findIntermediateOrder(afterOrder, nextOrder);
         }
@@ -53,15 +54,39 @@ public class TrackPlaylistService {
         repository.save(trackPlaylist);
     }
 
-    public void reorderTrack(Long playlistId, Long trackId, BigDecimal afterOrder) {
-        TrackPlaylist trackPlaylist = repository.findById(new PlaylistTrackId(playlistId, trackId))
-                .orElseThrow(() -> new RuntimeException("TrackPlaylist not found"));
+    public void bulkReorder(Long playlistId, List<Long> orderedTrackIds) {
+        List<TrackPlaylist> existingTracks = repository.findByPlaylistIdOrderByOrderAsc(playlistId);
+        Set<Long> existingTrackIds = existingTracks.stream()
+                .map(TrackPlaylist::getTrackId)
+                .collect(Collectors.toSet());
 
-        BigDecimal nextOrder = repository.findNextOrderByPlaylistIdAndOrderGreaterThan(playlistId, afterOrder);
-        BigDecimal newOrder = findIntermediateOrder(afterOrder, nextOrder);
+        if (!existingTrackIds.containsAll(orderedTrackIds) ||
+                orderedTrackIds.size() != existingTrackIds.size()) {
+            throw new IllegalArgumentException("Invalid track IDs provided for reordering");
+        }
 
-        trackPlaylist.setOrder(newOrder);
-        repository.save(trackPlaylist);
+        List<BigDecimal> newOrders = calculateNewOrders(orderedTrackIds.size());
+
+        for (int i = 0; i < orderedTrackIds.size(); i++) {
+            Long trackId = orderedTrackIds.get(i);
+            BigDecimal newOrder = newOrders.get(i);
+
+            TrackPlaylist trackPlaylist = repository.findById(new PlaylistTrackId(playlistId, trackId))
+                    .orElseThrow(() -> new RuntimeException("Track not found in playlist"));
+
+            trackPlaylist.setOrder(newOrder);
+            repository.save(trackPlaylist);
+        }
+    }
+
+    private List<BigDecimal> calculateNewOrders(int count) {
+        List<BigDecimal> orders = new ArrayList<>();
+        BigDecimal step = BigDecimal.valueOf(1000);
+
+        for (int i = 0; i < count; i++) {
+            orders.add(step.multiply(BigDecimal.valueOf(i + 1)));
+        }
+        return orders;
     }
 
 }

src/main/java/com/bivashy/backend/composer/service/TrackService.java

@@ -10,6 +10,8 @@ import org.springframework.web.server.ResponseStatusException;
 
 import com.bivashy.backend.composer.dto.track.AddLocalTrackRequest;
 import com.bivashy.backend.composer.dto.track.PlaylistTrackResponse;
+import com.bivashy.backend.composer.dto.track.TrackBulkReorderRequest;
+import com.bivashy.backend.composer.dto.track.TrackReorderAfterRequest;
 import com.bivashy.backend.composer.dto.track.TrackResponse;
 import com.bivashy.backend.composer.model.SourceTypes;
 import com.bivashy.backend.composer.model.Track;
@@ -83,7 +85,12 @@ public class TrackService {
                 .toList();
     }
 
+    public void bulkReorder(User user, Long playlistId, TrackBulkReorderRequest request) {
+        trackPlaylistService.bulkReorder(playlistId, request.trackIds());
+    }
+
     private String fileNameWithoutExtension(String fileName) {
         return fileName.replaceFirst("[.][^.]+$", "");
     }
+
 }