'use strict';

const LatLon = require('geodesy').LatLonSpherical;

/**
 * Compare date2 and date2 * 
 * @param {*} date1 
 * @param {*} date2 
 * @returns value > 0: date2 > date1
 */
function dateDiff(date1, date2) {
  return date2.getTime() - date1.getTime();
}

function last(array) {
  return array && array.length ? array[array.length - 1] : null;
}

function isEmpty(obj) {
  for (let x in obj) {
    if (Object.prototype.hasOwnProperty.call(obj, x)) {
      return false;
    } else {
      return true;
    }
  }
  return true;
}

function isDateTime(obj) {
  return (Object.prototype.toString.call(obj) === '[object Date]');
}

/**
 * Copy an Original Array or an Object without impacting on original data
 * Ref: https://stackoverflow.com/questions/36124363/deep-copying-objects-in-angular
 */
function clone(data) {
  let node;
  if (Array.isArray(data)) {
    node = data.length > 0 ? data.slice(0) : [];
    node.forEach((e, i) => {
      if ((typeof e === 'object' && e != {}) || (Array.isArray(e) && e.length > 0))
        node[i] = clone(e);
    });
  } else if (data && typeof data === 'object') {
    node = data instanceof Date ? new Date(data.valueOf()) : Object.assign({}, data);
    Object.keys(node).forEach((key) => {
      if ((typeof node[key] === 'object' && node[key] != {}) || (Array.isArray(node[key]) && node[key].length > 0))
        node[key] = clone(node[key]);
    });
  } else
    node = data;

  return node;
}

/**
 * Distance between 2 latlong points
 * @param {*} latLng fisrt point [lat, lon]
 * @param {*} latLng2 second point [lat, lon]
 */
function distance(latLng, latLng2) {
  if (!(latLng && latLng.length) || !(latLng2 && latLng2.length)) return 0;
  return (new LatLon(latLng[0], latLng[1])).distanceTo(new LatLon(latLng2[0], latLng2[1]));
}

module.exports = {
  dateDiff, last, isEmpty, isDateTime, clone, distance
};