import { getActiveElement } from '@/shared'

export type Orientation = 'horizontal' | 'vertical'
export type Direction = 'ltr' | 'rtl'

export const ENTRY_FOCUS = 'rovingFocusGroup.onEntryFocus'
export const EVENT_OPTIONS = { bubbles: false, cancelable: true }

export const MAP_KEY_TO_FOCUS_INTENT: Record<string, FocusIntent> = {
  ArrowLeft: 'prev',
  ArrowUp: 'prev',
  ArrowRight: 'next',
  ArrowDown: 'next',
  PageUp: 'first',
  Home: 'first',
  PageDown: 'last',
  End: 'last',
}

export function getDirectionAwareKey(key: string, dir?: Direction) {
  if (dir !== 'rtl')
    return key
  return key === 'ArrowLeft'
    ? 'ArrowRight'
    : key === 'ArrowRight'
      ? 'ArrowLeft'
      : key
}

type FocusIntent = 'first' | 'last' | 'prev' | 'next'

export function getFocusIntent(
  event: KeyboardEvent,
  orientation?: Orientation,
  dir?: Direction,
) {
  const key = getDirectionAwareKey(event.key, dir)
  if (orientation === 'vertical' && ['ArrowLeft', 'ArrowRight'].includes(key))
    return undefined
  if (orientation === 'horizontal' && ['ArrowUp', 'ArrowDown'].includes(key))
    return undefined
  return MAP_KEY_TO_FOCUS_INTENT[key]
}

export function focusFirst(candidates: HTMLElement[], preventScroll = false) {
  const PREVIOUSLY_FOCUSED_ELEMENT = getActiveElement()
  for (const candidate of candidates) {
    // if focus is already where we want to go, we don't want to keep going through the candidates
    if (candidate === PREVIOUSLY_FOCUSED_ELEMENT)
      return
    candidate.focus({ preventScroll })
    if (getActiveElement() !== PREVIOUSLY_FOCUSED_ELEMENT)
      return
  }
}

/**
 * Wraps an array around itself at a given start index
 * Example: `wrapArray(['a', 'b', 'c', 'd'], 2) === ['c', 'd', 'a', 'b']`
 */
export function wrapArray<T>(array: T[], startIndex: number) {
  return array.map((_, index) => array[(startIndex + index) % array.length])
}