import React, { useCallback } from 'react';
import ReactFlow, {
  ReactFlowProvider,
  useNodesState,
  useEdgesState,
  useReactFlow,
} from 'reactflow';
import { initialNodes, initialEdges } from './nodes-edges.js';
import 'reactflow/dist/style.css';

const getLayoutedElements = (nodes, edges) => {
  return { nodes, edges };
};

const LayoutFlow = () => {
  const { fitView } = useReactFlow();
  const [nodes, setNodes, onNodesChange] = useNodesState(initialNodes);
  const [edges, setEdges, onEdgesChange] = useEdgesState(initialEdges);

  const onLayout = useCallback(() => {
    const layouted = getLayoutedElements(nodes, edges);

    setNodes([...layouted.nodes]);
    setEdges([...layouted.edges]);

    window.requestAnimationFrame(() => {
      fitView();
    });
  }, [nodes, edges]);

  return (
    <ReactFlow
      nodes={nodes}
      edges={edges}
      onNodesChange={onNodesChange}
      onEdgesChange={onEdgesChange}
      fitView
    />
  );
};

export default function () {
  return (
    <ReactFlowProvider>
      <LayoutFlow />
    </ReactFlowProvider>
  );
}