// TYPES

import { SubscriptionMap } from "./auxilary";
import { WS } from "./index";

// requests
export interface IncomingMessage {
  // subscribing to channel
  subscribeChannel?: string;
  unsubscribeChannel?: string;

  //sending message
  messageChannel?: string;
  messageBody?: string;
}

// TRACKING
const subscriptions = new SubscriptionMap();

export function trackSubscription(ws: WS, channel: string): void {
  subscriptions.set(ws, channel);
  confirmSubscription(ws, channel);
}

export function removeSubscription(ws: WS, channel: string): void {
  subscriptions.delete(ws, channel);
  confirmSubscription(ws, channel);
}

export function forgetConnection(ws: WS): void {
  const channels = subscriptions.getChannelList(ws);
  channels?.forEach((channel) => {
    subscriptions.delete(ws, channel);
  });
}

// PROCESS MESSAGE
export function processMessage(ws: WS, messageString: string): void {
  const messageObject: IncomingMessage = parseMessage(messageString);

  if (typeof messageObject.subscribeChannel == "string") {
    trackSubscription(ws, messageObject.subscribeChannel);
  } else if (typeof messageObject.unsubscribeChannel == "string") {
    removeSubscription(ws, messageObject.unsubscribeChannel);
  } else if (
    typeof messageObject.messageChannel == "string" &&
    typeof messageObject.messageBody == "string"
  ) {
    sendMessage(messageObject.messageChannel, messageObject.messageBody);
  }
}

// MESSAGING
export function stringifyMessage(messageObject: Object): string {
  return JSON.stringify(messageObject);
}

export function parseMessage(messageString: string): Object {
  return JSON.parse(messageString);
}

export function sendMessage(channel: string, body: string): void {
  const messageObject = { channel, body };
  const messageString = stringifyMessage(messageObject);

  const subscribers = subscriptions.getClientList(channel);
  subscribers?.forEach((ws) => ws.send(messageString));
}

function confirmSubscription(ws: WS, channel: string): void {
  const messageObject = {
    channel: channel,
    subscribed: subscriptions.getChannelList(ws)?.has(channel),
  };
  const messageString = stringifyMessage(messageObject);
  ws.send(messageString);
}