import { findTabbableDescendants } from './tabbable'

export function scopeTab(node: HTMLElement, event: KeyboardEvent) {
  const tabbable = findTabbableDescendants(node)
  if (!tabbable.length) {
    event.preventDefault()
    return
  }

  const finalTabbable = tabbable[event.shiftKey ? 0 : tabbable.length - 1]
  const leavingFinalTabbable =
    finalTabbable === document.activeElement || node === document.activeElement

  if (!leavingFinalTabbable) {
    return
  }

  event.preventDefault()

  const target = tabbable[event.shiftKey ? tabbable.length - 1 : 0]

  if (target) {
    target.focus()
  }
}