export interface IDiscussionData {
  id: string;
  url: string;
  locked: boolean;
  repository: {
    nameWithOwner: string;
  };
  reactionCount: number;
  totalCommentCount: number;
  totalReplyCount: number;
  reactions: IReactionGroups;
}

export interface IUser {
  avatarUrl: string;
  login: string;
  url: string;
}

export interface IMessage<T> {
  giscus: T;
}

export interface IMetadataMessage {
  discussion: IDiscussionData;
  viewer: IUser;
}

function handleMessage(event: MessageEvent) {
  if (event.origin !== 'https://giscus.app') return;
  if (!(typeof event.data === 'object' && event.data.giscus)) return;

  const giscusData = event.data.giscus;

  // Make sure that the message is one that contains the discussion metadata.
  // This is necessary because other message types are also available.
  if ('discussion' in giscusData) {
    const discussion: IDiscussionData = giscusData.discussion;
    const viewer: IUser = giscusData.viewer;
    // Do whatever you want with it
  }
}

window.addEventListener('message', handleMessage);