export const SEX_LABELS = {
  buck: 'Buck',
  doe: 'Doe',
  unknown: 'Unknown',
}

export function formatAge(dob) {
  if (!dob) return 'Age unknown'

  const birth = new Date(`${dob}T00:00:00`)
  if (Number.isNaN(birth.getTime())) return 'Age unknown'

  const today = new Date()
  let years = today.getFullYear() - birth.getFullYear()
  let months = today.getMonth() - birth.getMonth()
  if (today.getDate() < birth.getDate()) months -= 1
  if (months < 0) {
    years -= 1
    months += 12
  }
  if (years < 0) return 'Age unknown'

  if (years === 0 && months === 0) return '<1m'
  if (years === 0) return `${months}m`
  if (months === 0) return `${years}y`
  return `${years}y ${months}m`
}

// Weight is always stored as decimal lbs; the `unit` argument (the user's
// `weight_unit` setting — see useWeightUnit) only controls display. lbs+oz
// rounds to the nearest ounce, carrying 16oz up to a pound so you never see
// "3 lb 16 oz".
export function formatWeight(weightLbs, unit = 'decimal_lbs') {
  if (weightLbs === null || weightLbs === undefined || weightLbs === '') return null
  const value = Number(weightLbs)
  if (Number.isNaN(value)) return null

  if (unit === 'lbs_oz') {
    const totalOz = Math.round(value * 16)
    const lbs = Math.floor(totalOz / 16)
    const oz = totalOz % 16
    return `${lbs} lb ${oz} oz`
  }

  return `${value.toFixed(2)} lbs`
}

export function formatDate(isoDate) {
  if (!isoDate) return null
  return new Date(`${isoDate}T00:00:00`).toLocaleDateString('en-US', {
    month: 'long',
    day: 'numeric',
    year: 'numeric',
  })
}