feat: Implement playlist reordering with position swapping and reload player on current playlist changes

tests/repositories/test_playlist.py

@@ -811,3 +811,78 @@ class TestPlaylistRepository:
         assert len(sounds) == TWO_SOUNDS
         assert sounds[0].id == sound2_id  # sound2 now at position 5
         assert sounds[1].id == sound1_id  # sound1 now at position 10
+
+    @pytest.mark.asyncio
+    async def test_reorder_playlist_sounds_position_swap(
+        self,
+        playlist_repository: PlaylistRepository,
+        test_session: AsyncSession,
+        ensure_plans: Any,
+    ) -> None:
+        """Test reordering sounds with position swapping (regression test)."""
+        # Create objects within this test
+        user = User(
+            email="test@example.com",
+            name="Test User",
+            password_hash=PasswordUtils.hash_password("password123"),
+            role="user",
+            is_active=True,
+            plan_id=ensure_plans[0].id,
+            credits=100,
+        )
+        test_session.add(user)
+        await test_session.commit()
+        await test_session.refresh(user)
+
+        user_id = user.id
+
+        playlist = Playlist(
+            user_id=user_id,
+            name="Test Playlist",
+            description="A test playlist",
+            genre="test",
+            is_main=False,
+            is_current=False,
+            is_deletable=True,
+        )
+        test_session.add(playlist)
+
+        # Create multiple sounds
+        sound1 = Sound(name="Sound 1", filename="sound1.mp3", type="SDB", hash="hash1")
+        sound2 = Sound(name="Sound 2", filename="sound2.mp3", type="SDB", hash="hash2")
+        test_session.add_all([playlist, sound1, sound2])
+        await test_session.commit()
+        await test_session.refresh(playlist)
+        await test_session.refresh(sound1)
+        await test_session.refresh(sound2)
+
+        # Extract IDs before async calls
+        playlist_id = playlist.id
+        sound1_id = sound1.id
+        sound2_id = sound2.id
+
+        # Add sounds to playlist at positions 0 and 1
+        await playlist_repository.add_sound_to_playlist(
+            playlist_id, sound1_id, position=0,
+        )
+        await playlist_repository.add_sound_to_playlist(
+            playlist_id, sound2_id, position=1,
+        )
+
+        # Verify initial order
+        sounds = await playlist_repository.get_playlist_sounds(playlist_id)
+        assert len(sounds) == TWO_SOUNDS
+        assert sounds[0].id == sound1_id  # sound1 at position 0
+        assert sounds[1].id == sound2_id  # sound2 at position 1
+
+        # Swap positions - this used to cause unique constraint violation
+        sound_positions = [(sound1_id, 1), (sound2_id, 0)]
+        await playlist_repository.reorder_playlist_sounds(
+            playlist_id, sound_positions,
+        )
+
+        # Verify swapped order
+        sounds = await playlist_repository.get_playlist_sounds(playlist_id)
+        assert len(sounds) == TWO_SOUNDS
+        assert sounds[0].id == sound2_id  # sound2 now at position 0
+        assert sounds[1].id == sound1_id  # sound1 now at position 1