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

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