export enum MessageType {
  ACK = 0,
  TEXT = 1,
}

export type ServerMessage = {
  type: MessageType;
  date: number;
};
export function isServerMessage(obj: unknown): obj is ServerMessage {
  if (typeof obj !== "object") return false;
  if (obj === null) return false;
  if (
    !Object.hasOwnProperty.call(obj, "type") ||
    typeof (obj as { type: unknown }).type !== "number" ||
    !Object.hasOwnProperty.call(MessageType, (obj as { type: number }).type)
  ) {
    return false;
  }
  if (
    !Object.hasOwnProperty.call(obj, "date") ||
    typeof (obj as { date: unknown }).date !== "number"
  ) {
    return false;
  }

  return true;
}

export type TextMessage = ServerMessage & {
  type: MessageType.TEXT;
  author: string;
  content: string;
};
export function isTextMessage(obj: unknown): obj is TextMessage {
  if (!isServerMessage(obj)) return false;
  if (obj.type !== MessageType.TEXT) return false;
  if (
    !Object.hasOwnProperty.call(obj, "author") ||
    typeof (obj as ServerMessage & { author: unknown }).author !== "string"
  ) {
    return false;
  }
  if (
    !Object.hasOwnProperty.call(obj, "author") ||
    typeof (obj as ServerMessage & { content: unknown }).content !== "string"
  ) {
    return false;
  }
  return true;
}

export type AckMessage = ServerMessage & {
  type: MessageType.ACK;
};
export function isAckMessage(obj: unknown): obj is AckMessage {
  if (!isServerMessage(obj)) return false;
  if (obj.type !== MessageType.ACK) return false;
  return true;
}