import React, { useState } from 'react';

import ReactFlow, { removeElements, addEdge } from 'react-flow-renderer';

const onLoad = (reactFlowInstance) => reactFlowInstance.fitView();

const onNodeMouseEnter = (event, node) => console.log('mouse enter:', node);
const onNodeMouseMove = (event, node) => console.log('mouse move:', node);
const onNodeMouseLeave = (event, node) => console.log('mouse leave:', node);
const onNodeContextMenu = (event, node) => {
  event.preventDefault();
  console.log('context menu:', node);
};

const initialElements = [
  {
    id: '1',
    sourcePosition: 'right',
    type: 'input',
    className: 'dark-node',
    data: { label: 'Input' },
    position: { x: 0, y: 80 },
  },
  { id: '2', sourcePosition: 'right', targetPosition: 'left', data: { label: 'A Node' }, position: { x: 250, y: 0 } },
  { id: '3', sourcePosition: 'right', targetPosition: 'left', data: { label: 'Node 3' }, position: { x: 250, y: 160 } },
  { id: '4', sourcePosition: 'right', targetPosition: 'left', data: { label: 'Node 4' }, position: { x: 500, y: 0 } },
  { id: '5', sourcePosition: 'top', targetPosition: 'bottom', data: { label: 'Node 5' }, position: { x: 500, y: 100 } },
  { id: '6', sourcePosition: 'bottom', targetPosition: 'top', data: { label: 'Node 6' }, position: { x: 500, y: 230 } },
  { id: '7', sourcePosition: 'right', targetPosition: 'left', data: { label: 'Node 7' }, position: { x: 750, y: 50 } },
  { id: '8', sourcePosition: 'right', targetPosition: 'left', data: { label: 'Node 8' }, position: { x: 750, y: 300 } },

  { id: 'e1-2', source: '1', type: 'smoothstep', target: '2', animated: true },
  { id: 'e1-3', source: '1', type: 'smoothstep', target: '3', animated: true },
  { id: 'e1-4', source: '2', type: 'smoothstep', target: '4', label: 'edge label' },
  { id: 'e3-5', source: '3', type: 'smoothstep', target: '5', animated: true },
  { id: 'e3-6', source: '3', type: 'smoothstep', target: '6', animated: true },
  { id: 'e5-7', source: '5', type: 'smoothstep', target: '7', animated: true },
  { id: 'e6-8', source: '6', type: 'smoothstep', target: '8', animated: true },
];

const HorizontalFlow = () => {
  const [elements, setElements] = useState(initialElements);
  const onElementsRemove = (elementsToRemove) => setElements((els) => removeElements(elementsToRemove, els));
  const onConnect = (params) => setElements((els) => addEdge(params, els));
  const changeClassName = () => {
    setElements((elms) =>
      elms.map((el) => {
        if (el.type === 'input') {
          el.className = el.className ? '' : 'dark-node';
        }

        return { ...el };
      })
    );
  };

  return (
    <ReactFlow
      elements={elements}
      onElementsRemove={onElementsRemove}
      onConnect={onConnect}
      onLoad={onLoad}
      selectNodesOnDrag={false}
      onNodeMouseEnter={onNodeMouseEnter}
      onNodeMouseMove={onNodeMouseMove}
      onNodeMouseLeave={onNodeMouseLeave}
      onNodeContextMenu={onNodeContextMenu}
    >
      <button onClick={changeClassName} style={{ position: 'absolute', right: 10, top: 30, zIndex: 4 }}>
        change class name
      </button>
    </ReactFlow>
  );
};

export default HorizontalFlow;