import React from 'react'

import PropTypes from 'prop-types'

import { camelize } from '../lib/String'

const evtNames = ['click', 'mouseover', 'recenter'];

const wrappedPromise = function() {

var wrappedPromise = {},

promise = new Promise(function (resolve, reject) {

wrappedPromise.resolve = resolve;

wrappedPromise.reject = reject;

});

wrappedPromise.then = promise.then.bind(promise);

wrappedPromise.catch = promise.catch.bind(promise);

wrappedPromise.promise = promise;

return wrappedPromise;

}

export class HeatMap extends React.Component {

componentDidMount() {

this.heatMapPromise = wrappedPromise();

this.renderHeatMap();

}

componentDidUpdate(prevProps) {

if ((this.props.map !== prevProps.map) ||

(this.props.position !== prevProps.position)) {

if (this.heatMap) {

this.heatMap.setMap(null);

this.renderHeatMap();

}

}

}

componentWillUnmount() {

if (this.heatMap) {

this.heatMap.setMap(null);

}

}

renderHeatMap() {

let {

map, google, positions, mapCenter, icon, gradient, radius, opacity

} = this.props;

if (!google) {

return null;

}

positions = positions.map((pos) => {

return new google.maps.LatLng(pos.lat, pos.lng);

});

const pref = {

map: map,

data: positions,

};

this.heatMap = new google.maps.visualization.HeatmapLayer(pref);

this.heatMap.set('gradient', gradient);

this.heatMap.set('radius', radius === undefined ? 20 : radius);

this.heatMap.set('opacity', opacity === undefined ? 0.2 : opacity);

evtNames.forEach(e => {

this.heatMap.addListener(e, this.handleEvent(e));

});

this.heatMapPromise.resolve(this.heatMap);

}

getHeatMap() {

return this.heatMapPromise;

}

handleEvent(evt) {

return (e) => {

const evtName = `on${camelize(evt)}`

if (this.props[evtName]) {

this.props[evtName](this.props, this.heatMap, e);

}

}

}

render() {

return null;

}

}

HeatMap.propTypes = {

position: PropTypes.object,

map: PropTypes.object,

icon: PropTypes.string

}

evtNames.forEach(e => HeatMap.propTypes[e] = PropTypes.func)

HeatMap.defaultProps = {

name: 'HeatMap'

}

export default HeatMap