jku-ba-react/src/Google.js

import React from "react";
import GoogleMapReact from "google-map-react";
import "./css/maps.css";
import apiKey from './config/googleApiKey.js';
import {calcDistance} from './helpers/distance';
import {longitude, latitude, mapWidth, mapHeight, markerIcon, testPath} from "./config/variables";
import {Button} from "reactstrap";

const svgStyle = {
  top: "-20",
  left: "-8",
  position: "absolute"
};

const Marker = ({ text }) =>
  <div>
    <svg height={20} viewBox="0 0 24 24" style={svgStyle}>
      <path d={markerIcon}/>
    </svg>
    <p>{text}</p>
  </div>;

export default class Google extends React.Component{
  state = {
    latitude: latitude,
    longitude: longitude,
    zoom: 15,
    distance: 0,
    path: testPath,
    draggable: true
  }

  componentDidUpdate(){
    this.drawPath()
  }

  getRoute = (lng, lat) => {
    let pathCopy = this.state.path.slice();
    var end = [lat, lng];
    if (this.state.path.length < 1){
      pathCopy.push(end)
      this.setState({path: pathCopy})
    } else {
      var start = this.state.path[this.state.path.length-1];
      var proxyurl = "https://cors-anywhere.herokuapp.com/";
      var baseUrl = "https://maps.googleapis.com/maps/api/directions/json?origin="
      var url = baseUrl + start[0] + "," + start[1] + "&destination=" + end[0] + "," + end[1] + "&key=" + apiKey;
      var reqOptions = {
        method:'GET',
        mode: 'cors',
        headers:{
          'Access-Control-Allow-Origin':'*'
        },
      }

      fetch(proxyurl + url, reqOptions)
        .then(response => response.json())
        .then(data => {
          let routes = data.routes
          if(routes.length > 0){
            let steps = routes[0].legs[0].steps
            steps.forEach(step => {
              pathCopy.push([step.end_location.lat, step.end_location.lng])
            })
          } else{
            pathCopy.push(end)
          }
          this.setState({path: pathCopy})
          this.getDistance()
        })
        .catch((error) =>{
          console.error(error);
        });
    }
  }

  onMarkerInteraction = (childKey, childProps, mouse) => {
    this.setState({draggable: false});
  }

  addMarker = (event) => {
    const lng = event.lng
    const lat = event.lat

//    let pathCopy = this.state.path.slice();
//    pathCopy.push([lat, lng])
//    this.setState({path: pathCopy})

    this.getRoute(lng, lat);
    this.getDistance()
  }

  updateMarker = (childKey, childProps, mouse) => {
    const lng = mouse.lng
    const lat = mouse.lat
    console.log("new position (marker", childKey, "):", lat, lng)
    let pathCopy = this.state.path.slice();
    pathCopy[childKey] = [lat, lng]
    this.setState({path: pathCopy, draggable: true})
    this.getDistance()
  }

  getDistance = () => {
    let dst = calcDistance(this.state.path)
    this.setState({distance: dst})
  }

  clearPath = () => {
    this.setState({path: [], distance: 0})
  }

  drawPath = () => {
    let path = this.state.path.map(p => {
      return {lat: p[0], lng: p[1]}
    })
    let map = this.state.map
    let maps = this.state.maps
    new maps.Polyline({
      path: path,
      geodesic: true,
      strokeColor: "#212529",
      strokeOpacity: 1.0,
      strokeWeight: 4,
      map,
    });
  }

  handleApiLoaded = (map, maps) => {
    this.setState({map: map, maps: maps})
  }

  render() {
    const position = [this.state.latitude, this.state.longitude]
    return (
      <div>
        <div className="map" style={{height: mapHeight, width: mapWidth}}>
          <GoogleMapReact
            bootstrapURLKeys={{ key: apiKey }}
            defaultCenter={position}
            defaultZoom={this.state.zoom}
            yesIWantToUseGoogleMapApiInternals
            layerTypes={['TrafficLayer', 'TransitLayer']}
            onClick={(e, c) => this.addMarker(e, c)}
            draggable={this.state.draggable}
            onChildMouseDown={this.onMarkerInteraction}
            onChildMouseUp={this.updateMarker}
            onGoogleApiLoaded={({map, maps}) => this.handleApiLoaded(map, maps)}
          >
            {this.state.path.map((pos, idx) =>
              <Marker
                lat={pos[0]}
                lng={pos[1]}
                text={idx}
                key={idx}
                draggable={true}
                onDragEnd={(e) => this.updateMarker(idx, e)}
              />
            )}

          </GoogleMapReact>
        </div>

        <div className="mapInfo">
          <Button onClick={this.clearPath}>Clear path</Button>
          <Button onClick={this.getDistance}>Calculate Distance</Button>
          <p>
            Distanz: {Math.round(this.state.distance*100)/100} km
          </p>
        </div>
      </div>
    );
  }
}