import { rtc } from '@chat-app/shared';
import type { CallSignal } from '@chat-app/shared/rtc';
import type { AppSupabaseClient } from '@chat-app/shared/supabase';

// Thin wrapper around Supabase realtime broadcast for call signaling.
// One channel per peer userId. Subscriptions live for the lifetime of
// the AuthProvider's session; teardown returns a no-arg unsubscribe.

export type SignalListener = (signal: CallSignal) => void;

export function subscribeCallSignals(
  client: AppSupabaseClient,
  myUserId: string,
  onSignal: SignalListener,
): () => void {
  const ch = client.channel(rtc.signalTopic(myUserId));
  ch.on('broadcast', { event: 'signal' }, (msg) => {
    if (msg.payload && typeof msg.payload === 'object') {
      onSignal(msg.payload as CallSignal);
    }
  });
  void ch.subscribe();
  return () => {
    void client.removeChannel(ch);
  };
}

export async function sendCallSignal(
  client: AppSupabaseClient,
  toUserId: string,
  payload: CallSignal,
): Promise<void> {
  const ch = client.channel(rtc.signalTopic(toUserId));
  await ch.subscribe();
  await ch.send({ type: 'broadcast', event: 'signal', payload });
  await client.removeChannel(ch);
}