removeNode method

void removeNode(String nodeId)

Removes a node from the graph along with all its connections.

This method will:

1. Remove the node from the graph
2. Remove it from the selection if selected
3. Remove all connections involving this node
4. Remove the node from any group annotations
5. Delete empty group annotations that no longer contain any nodes

Triggers the onNodeDeleted callback after successful removal.

Implementation

void removeNode(String nodeId) {
  final nodeToDelete = _nodes[nodeId]; // Capture before deletion
  runInAction(() {
    _nodes.remove(nodeId);
    _selectedNodeIds.remove(nodeId);
    // Remove from spatial index
    _spatialIndex.removeNode(nodeId);

    // Remove connections involving this node from spatial index first
    final connectionsToRemove = _connections
        .where((c) => c.sourceNodeId == nodeId || c.targetNodeId == nodeId)
        .toList();
    for (final connection in connectionsToRemove) {
      _spatialIndex.removeConnection(connection.id);
      // Also remove from path cache to prevent stale rendering
      _connectionPainter?.removeConnectionFromCache(connection.id);
    }

    // Then remove from connections list
    _connections.removeWhere(
      (c) => c.sourceNodeId == nodeId || c.targetNodeId == nodeId,
    );

    // Note: Annotations are notified via MobX reaction in AnnotationController
    // that watches _nodes.keys for additions/deletions
  });
  // Fire event after successful removal
  if (nodeToDelete != null) {
    events.node?.onDeleted?.call(nodeToDelete);
  }
}