export function parseAspectRatio(value?: string | null): number {
  if (!value) return 16 / 9
  const [widthRaw, heightRaw] = value.split(':')
  const width = Number(widthRaw)
  const height = Number(heightRaw)
  if (!Number.isFinite(width) || !Number.isFinite(height) || width <= 0 || height <= 0) {
    return 16 / 9
  }
  return width / height
}

export function cssAspectRatio(value?: string | null): string {
  if (!value?.includes(':')) return '16 / 9'
  return value.replace(':', ' / ')
}

/** Preview box that keeps the slot ratio: landscape is wide, portrait is tall. */
export function slotPreviewSize(value?: string | null): { width: number; height: number } {
  const aspect = parseAspectRatio(value)
  const long = 220
  if (aspect >= 1) {
    const width = Math.min(360, Math.round(long * aspect))
    return { width, height: Math.round(width / aspect) }
  }
  const height = long
  return { width: Math.round(height * aspect), height }
}