import fs from 'node:fs/promises';
import os from 'node:os';
import path from 'node:path';
import { afterAll, beforeAll, describe, expect, it } from 'vitest';
import { GET } from './route';

let dir: string;

beforeAll(async () => {
  // Same pattern as app/api/state/route.test.ts: point the DB singleton at a throwaway file so
  // this test never touches ./db/flight.db. getGameDb() reads the env var on first call, and
  // vitest gives each test file its own module registry (fresh singleton).
  dir = await fs.mkdtemp(path.join(os.tmpdir(), 'flight-events-'));
  process.env.FLIGHT_DB_PATH = path.join(dir, 'events.db');
});

afterAll(async () => {
  delete process.env.FLIGHT_DB_PATH;
  await fs.rm(dir, { recursive: true, force: true });
});

describe('GET /api/events', () => {
  it('streams SSE with the current snapshot as the first event', async () => {
    const res = await GET();
    expect(res.status).toBe(200);
    expect(res.headers.get('content-type')).toContain('text/event-stream');
    expect(res.headers.get('cache-control')).toBe('no-cache');
    expect(res.headers.get('x-accel-buffering')).toBe('no');

    const reader = (res.body as ReadableStream<Uint8Array>).getReader();
    try {
      const { value } = await reader.read(); // first chunk: the initial snapshot event
      const text = new TextDecoder().decode(value);
      expect(text.startsWith('data: ')).toBe(true);
      const snap = JSON.parse(text.slice('data: '.length)) as Record<string, unknown>;
      expect(typeof (snap.simState as { clockMs: number }).clockMs).toBe('number');
    } finally {
      await reader.cancel(); // → stream cancel → unsubscribe from the registry
    }
  });
});