feat(playlists): reorder tracks

proto/library.proto

@@ -11,6 +11,7 @@ service Library {
 	rpc DeletePlaylist(DeletePlaylistRequest) returns (google.protobuf.Empty);
 	rpc AddTrackToPlaylist(AddTrackToPlaylistRequest) returns (google.protobuf.Empty);
 	rpc RemoveTrackFromPlaylist(RemoveTrackFromPlaylistRequest) returns (google.protobuf.Empty);
+	rpc SwapTracks(SwapTracksRequest) returns (TrackList);
 }
 
 message TrackList {
@@ -56,3 +57,9 @@ message RemoveTrackFromPlaylistRequest {
 	uint32 playlist_id = 1;
 	uint32 track_rank = 2;
 }
+
+message SwapTracksRequest {
+	uint32 playlist_id = 1;
+	uint32 a_rank = 2;
+	uint32 b_rank = 3;
+}

src/database/tracks.rs

@@ -340,3 +340,31 @@ pub async fn remove_track_from_playlist(
 
     Ok(len == 1)
 }
+
+pub async fn swap_playlist_tracks(
+    pool: &Pool,
+    playlist_id: u32,
+    a_rank: u32,
+    b_rank: u32,
+) -> Result<bool, rusqlite::Error> {
+    let manager = pool.get().await.unwrap();
+    let mut connection = manager.lock().unwrap();
+
+    let tx = connection.transaction()?;
+
+    tx.execute(
+        "UPDATE playlist_tracks SET rank = CASE WHEN rank = ?2 THEN - ?3 - 1 ELSE - ?2 - 1 END WHERE playlist_id = ?1 AND rank IN (?2, ?3)",
+        [playlist_id, a_rank, b_rank],
+    )?;
+
+    let len = tx.execute("UPDATE playlist_tracks SET rank = - rank - 1 WHERE playlist_id = ?1 AND rank IN (- ?2 - 1, - ?3 - 1)", [playlist_id, a_rank, b_rank])?;
+
+    if len != 2 {
+        tx.rollback()?;
+        return Ok(false);
+    }
+
+    tx.commit()?;
+
+    Ok(true)
+}

src/library.rs

@@ -8,14 +8,14 @@ use walkdir::{DirEntry, WalkDir};
 use crate::{
     checksum::generate_hash,
     database::tracks::{
-        add_track_to_playlist, create_playlist, delete_playlist, get_playlists, get_tracks,
-        insert_tracks, remove_track_from_playlist,
+        add_track_to_playlist, create_playlist, delete_playlist, get_playlist, get_playlists,
+        get_tracks, insert_tracks, remove_track_from_playlist, swap_playlist_tracks,
     },
     music::metadata::{extract_track_data, TrackMetadata},
     proto::library::{
         library_server::Library, AddTrackToPlaylistRequest, CreatePlaylistRequest,
         CreatePlaylistResponse, DeletePlaylistRequest, ListPlaylistsResponse,
-        RemoveTrackFromPlaylistRequest, Track, TrackList,
+        RemoveTrackFromPlaylistRequest, SwapTracksRequest, Track, TrackList,
     },
     state::GrooveState,
 };
@@ -139,6 +139,33 @@ impl Library for LibraryService {
 
         Ok(Response::new(()))
     }
+
+    async fn swap_tracks(
+        &self,
+        request: Request<SwapTracksRequest>,
+    ) -> Result<Response<TrackList>, Status> {
+        let input = request.get_ref();
+
+        let Ok(success) =
+            swap_playlist_tracks(&self.pool, input.playlist_id, input.a_rank, input.b_rank).await
+        else {
+            return Err(Status::internal(""));
+        };
+
+        if !success {
+            return Err(Status::internal(""));
+        }
+
+        let Ok(playlist) = get_playlist(&self.pool, input.playlist_id).await else {
+            return Err(Status::internal(""));
+        };
+
+        let response = TrackList {
+            tracks: playlist.tracks,
+        };
+
+        Ok(Response::new(response))
+    }
 }
 
 pub async fn index_path(path: PathBuf, db: &Pool, path_id: u64) -> Result<(), rusqlite::Error> {