export type UnitPreference = 'METRIC' | 'IMPERIAL'

const KM_TO_MILES = 0.621371
const METERS_TO_FEET = 3.28084

export function formatDistance(km: number, unit: UnitPreference): string {
  if (unit === 'IMPERIAL') {
    if (km < 0.1) {
      const feet = km * 1000 * METERS_TO_FEET
      return `${Math.round(feet)} ft`
    }
    const miles = km * KM_TO_MILES
    return `${miles.toFixed(2)} mi`
  }
  if (km < 1) {
    const meters = km * 1000
    return `${Math.round(meters)} m`
  }
  return `${km.toFixed(2)} km`
}

export function formatDistanceShort(km: number, unit: UnitPreference): string {
  if (unit === 'IMPERIAL') {
    const miles = km * KM_TO_MILES
    if (miles < 0.1) {
      return `${Math.round(miles * 5280)} ft`
    }
    return `${miles.toFixed(1)} mi`
  }
  if (km < 1) {
    return `${Math.round(km * 1000)} m`
  }
  return `${km.toFixed(1)} km`
}

export function formatRadius(meters: number, unit: UnitPreference): string {
  if (unit === 'IMPERIAL') {
    const feet = meters * METERS_TO_FEET
    if (feet < 5280) {
      return `${Math.round(feet)} ft`
    }
    const miles = feet / 5280
    return `${miles.toFixed(1)} mi`
  }
  if (meters < 1000) {
    return `${Math.round(meters)} m`
  }
  return `${(meters / 1000).toFixed(1)} km`
}

export function kmToMiles(km: number): number {
  return km * KM_TO_MILES
}

export function metersToFeet(meters: number): number {
  return meters * METERS_TO_FEET
}