import type { Message, ViewerAPIMessageSource } from './types';

/**
 * @ignore
 */
type MessageHandler = (event: MessageEvent) => void;

/**
 * @ignore
 */
export const listenToMessages = (
  incomingMessageHandler: MessageHandler
): void => {
  window.addEventListener('message', incomingMessageHandler);
};

/**
 * @ignore
 */
export const unListenToMessages = (
  incomingMessageHandler: MessageHandler
): void => {
  window.removeEventListener('message', incomingMessageHandler);
};

/**
 * @ignore
 */
export const parseIncomingMessage = (
  event: MessageEvent,
  source: ViewerAPIMessageSource
): Message | undefined => {
  try {
    if (!event.data || typeof event.data !== 'string') {
      return undefined;
    }

    const message = JSON.parse(event.data) as Message;

    if (message?.source !== source) {
      return undefined;
    }

    return message;
  } catch (error) {
    console.error(
      `${source} - Could not parse the latest message`,
      event,
      error
    );
    return undefined;
  }
};