import type { KeyboardEvent } from "react";

type IMEKeyboardEvent = KeyboardEvent<HTMLElement>;

export function isIMEComposing(
  event: IMEKeyboardEvent,
  isComposing = false,
): boolean {
  return isComposing || event.nativeEvent.isComposing || event.keyCode === 229;
}

// Safari emits the Enter that confirms a composition after compositionend,
// with isComposing false and keyCode 13. React has already flushed the
// composing state by the time that keydown runs.
export const COMPOSITION_CONFIRM_ENTER_MS = 50;

export function isCompositionConfirmEnter(
  event: IMEKeyboardEvent,
  compositionEndedAt: number,
  now = Date.now(),
): boolean {
  if (event.key !== "Enter" || event.shiftKey || isIMEComposing(event)) {
    return false;
  }
  const elapsed = now - compositionEndedAt;
  return elapsed >= 0 && elapsed < COMPOSITION_CONFIRM_ENTER_MS;
}