import randomColor from 'randomcolor';
import { polygon } from '@turf/helpers';

export function getProp(obj, ...props) {

  if (props.length === 0) throw new Error("You must at least provide one property.");

  const prop = props.shift();
  const exists = obj.hasOwnProperty(prop);

  if (props.length === 0) {
    return exists ? obj[prop] : undefined;
  }

  if (obj[prop] === undefined) {
    return undefined;
  }

  return getProp(obj[prop], ...props);
}

export function parseSequence(str) {
  return str.replace(/\r?\n?\t?/g, '').split(' ');
}

const colors = {};

export function getColor(key, opts) {
  if (key in colors) {
    return colors[key];
  }
  const color = randomColor(opts);
  colors[key] = color;
  return color;
}

export function toRadians(angleInDegrees) {
  return angleInDegrees * Math.PI / 180;
}

export function toDegrees(angleInRadians) {
  return angleInRadians * 180 / Math.PI;
}

export function circleToPolygon(center, radius, numberOfSegments, properties) {
  const n = numberOfSegments ? numberOfSegments : 32;
  const flatCoordinates = [];
  const coordinates = [];
  for (var i = 0; i < n; ++i) {
    flatCoordinates.push(...offset(center, radius, 2 * Math.PI * i / n));
  }
  flatCoordinates.push(flatCoordinates[0], flatCoordinates[1]);

  for (let i = 0, j = 0; j < flatCoordinates.length; j += 2) {
    coordinates[i++] = flatCoordinates.slice(j, j + 2);
  }

  return polygon([coordinates.reverse()], properties);
};

export function offset(c1, distance, bearing) {
  const lat1 = toRadians(c1[1]);
  const lon1 = toRadians(c1[0]);
  const dByR = distance / 6378137; // distance divided by 6378137 (radius of the earth) wgs84
  const lat = Math.asin(
    Math.sin(lat1) * Math.cos(dByR) +
    Math.cos(lat1) * Math.sin(dByR) * Math.cos(bearing));
  const lon = lon1 + Math.atan2(
    Math.sin(bearing) * Math.sin(dByR) * Math.cos(lat1),
    Math.cos(dByR) - Math.sin(lat1) * Math.sin(lat));
  return [toDegrees(lon), toDegrees(lat)];
}