export type AutocompleteKeyDecision =
  | { action: 'none' }
  | { action: 'escape' }
  | { action: 'move'; nextIndex: number }
  | { action: 'select'; index: number }

export function decideAutocompleteKeyAction(params: {
  key: string
  selectedIndex: number
  suggestionsCount: number
}): AutocompleteKeyDecision {
  if (params.key === 'Escape') {
    return { action: 'escape' }
  }
  if (params.key === 'ArrowDown') {
    const nextIndex = params.selectedIndex < params.suggestionsCount - 1 ? params.selectedIndex + 1 : params.selectedIndex
    return { action: 'move', nextIndex }
  }
  if (params.key === 'ArrowUp') {
    const nextIndex = params.selectedIndex > 0 ? params.selectedIndex - 1 : -1
    return { action: 'move', nextIndex }
  }
  if (params.key === 'Enter' && params.selectedIndex >= 0) {
    return { action: 'select', index: params.selectedIndex }
  }
  return { action: 'none' }
}