import { describe, expect, it } from 'vitest';
import { broadcast, subscribe } from './sse';

// ISS-129 (v0.57.0): the fan-out registry behind /api/events — plain Set semantics, so no DB or
// server needed. Subscribers leak across tests in this file (module-level state), which is fine:
// each test only asserts on its own arrays.

describe('lib/sse', () => {
  it('delivers broadcasts to subscribers and stops after unsubscribe', () => {
    const a: string[] = [];
    const b: string[] = [];
    const unsubA = subscribe((t) => a.push(t));
    const unsubB = subscribe((t) => b.push(t));

    broadcast('x');
    expect(a).toEqual(['x']);
    expect(b).toEqual(['x']);

    unsubA();
    broadcast('y');
    expect(a).toEqual(['x']); // unsubscribed — no more events
    expect(b).toEqual(['x', 'y']);
    unsubB();
  });

  it('a throwing subscriber does not break the others', () => {
    const got: string[] = [];
    subscribe(() => {
      throw new Error('boom');
    });
    const unsub = subscribe((t) => got.push(t));
    broadcast('z');
    expect(got).toEqual(['z']);
    unsub();
  });

  it('unsubscribe is idempotent', () => {
    const got: string[] = [];
    const unsub = subscribe((t) => got.push(t));
    unsub();
    unsub(); // second call must not throw
    broadcast('w');
    expect(got).toEqual([]);
  });
});