export function formatCost(usd: number): string {
  if (usd < 0.01) return `$${usd.toFixed(4)}`
  if (usd < 1) return `$${usd.toFixed(3)}`
  return `$${usd.toFixed(2)}`
}

export function formatTokens(n: number): string {
  if (n >= 1_000_000_000) return `${(n / 1_000_000_000).toFixed(1)}B`
  if (n >= 1_000_000) return `${(n / 1_000_000).toFixed(1)}M`
  if (n >= 1_000) return `${(n / 1_000).toFixed(1)}K`
  return n.toString()
}

export function formatDuration(minutes: number): string {
  if (minutes < 60) return `${Math.round(minutes)}m`
  const hours = Math.floor(minutes / 60)
  const mins = Math.round(minutes % 60)
  if (hours < 24) return `${hours}h ${mins}m`
  const days = Math.floor(hours / 24)
  const remainingHours = hours % 24
  return `${days}d ${remainingHours}h`
}

export function formatNumber(n: number): string {
  return n.toLocaleString()
}

// Local-timezone YYYY-MM-DD bucket. Matches ccusage's _date-utils.ts so daily
// totals agree to the cent — UTC slicing shifts cross-midnight tokens.
const LOCAL_DATE_FORMATTER = new Intl.DateTimeFormat('en-CA', {
  year: 'numeric',
  month: '2-digit',
  day: '2-digit',
})

export function formatLocalDate(d: Date): string {
  return LOCAL_DATE_FORMATTER.format(d)
}