import { comparatorDistanceUnits } from '@adalo/constants'
import {
  asKilometers,
  Coordinate,
  kilometersBetweenLocations,
} from '../location'

describe('utils/location', () => {
  describe('asKilometers(...)', () => {
    test('Preserves kilometers', () => {
      const inputValue = 14.389
      const result = asKilometers(
        inputValue,
        comparatorDistanceUnits.KILOMETERS
      )

      expect(result).toBe(inputValue)
    })

    test('Correctly converts 2000 miles', () => {
      const inputValue = 2000
      const result = asKilometers(inputValue, comparatorDistanceUnits.MILES)

      const expected = 3218.688 // Source: https://www.unitconverters.net/length/miles-to-km.htm

      expect(result).toBe(expected)
    })
  })

  describe('kilometersBetweenLocations(a, b)', () => {
    test('Finds correct distance between two nearby points', () => {
      const pointA: Coordinate = {
        latitude: 49.3040476,
        longitude: -123.1391123,
      }
      const pointB: Coordinate = {
        latitude: 49.3038325,
        longitude: -123.1567494,
      }

      const result = kilometersBetweenLocations(pointA, pointB)
      const expectedKms = 1.279 // Source: https://www.movable-type.co.uk/scripts/latlong.html
      const epsilon = expectedKms * 0.01 // Accuracy up to 1% because finding exact reference values is difficult.

      expect(Math.abs(result - expectedKms)).toBeLessThan(epsilon)
    })

    test('Finds correct distance between two distant points', () => {
      const pointA: Coordinate = {
        latitude: 49.261098,
        longitude: -123.113982,
      }
      const pointB: Coordinate = {
        latitude: -33.872979,
        longitude: 151.206104,
      }

      const result = kilometersBetweenLocations(pointA, pointB)
      const expectedKms = 12500 // Source: https://www.movable-type.co.uk/scripts/latlong.html
      const epsilon = expectedKms * 0.01 // Accuracy up to 1% because finding exact reference values is difficult.

      expect(Math.abs(result - expectedKms)).toBeLessThan(epsilon)
    })

    test('Distance between same location is zero', () => {
      const point: Coordinate = {
        latitude: 42.331427,
        longitude: -83.0457538,
      }

      const result = kilometersBetweenLocations(point, point)

      expect(result).toBe(0)
    })
  })
})