import { EventEmitter } from 'node:events';
import { describe, it, expect } from 'bun:test';

// ─── BrowserManager basic unit tests ─────────────────────────────

describe('BrowserManager defaults', () => {
  it('getConnectionMode defaults to launched', async () => {
    const { BrowserManager } = await import('../src/browser-manager');
    const bm = new BrowserManager();
    expect(bm.getConnectionMode()).toBe('launched');
  });

  it('getRefMap returns empty array initially', async () => {
    const { BrowserManager } = await import('../src/browser-manager');
    const bm = new BrowserManager();
    expect(bm.getRefMap()).toEqual([]);
  });
});

// ─── resolveDisconnectCause ──────────────────────────────────────
//
// Pinning the clean-vs-crash distinction matters because gbd's
// HealthMonitor consumes our exit code (0 = don't restart, !=0 =
// restart). A regression here brings back the "Cmd+Q makes the browser
// keep coming back" UX bug.

function makeFakeBrowser(opts: {
  exitCode: number | null;
  signalCode: NodeJS.Signals | null;
  /** ms before emitting 'exit'; default = already exited at construction */
  exitDelay?: number;
}): { process(): { exitCode: number | null; signalCode: NodeJS.Signals | null; once: EventEmitter['once'] } } {
  const ee = new EventEmitter();
  const state = {
    exitCode: opts.exitDelay != null ? null : opts.exitCode,
    signalCode: opts.exitDelay != null ? null : opts.signalCode,
    once: ee.once.bind(ee),
  };
  if (opts.exitDelay != null) {
    setTimeout(() => {
      state.exitCode = opts.exitCode;
      state.signalCode = opts.signalCode;
      ee.emit('exit', opts.exitCode, opts.signalCode);
    }, opts.exitDelay);
  }
  return { process: () => state };
}

describe('resolveDisconnectCause', () => {
  it('clean: process already exited with code 0', async () => {
    const { resolveDisconnectCause } = await import('../src/browser-manager');
    const fake = makeFakeBrowser({ exitCode: 0, signalCode: null });
    expect(await resolveDisconnectCause(fake as never)).toBe('clean');
  });

  it('crash: non-zero exit code', async () => {
    const { resolveDisconnectCause } = await import('../src/browser-manager');
    const fake = makeFakeBrowser({ exitCode: 1, signalCode: null });
    expect(await resolveDisconnectCause(fake as never)).toBe('crash');
  });

  it('crash: SIGSEGV', async () => {
    const { resolveDisconnectCause } = await import('../src/browser-manager');
    const fake = makeFakeBrowser({ exitCode: null, signalCode: 'SIGSEGV' });
    expect(await resolveDisconnectCause(fake as never)).toBe('crash');
  });

  it('crash: SIGKILL', async () => {
    const { resolveDisconnectCause } = await import('../src/browser-manager');
    const fake = makeFakeBrowser({ exitCode: null, signalCode: 'SIGKILL' });
    expect(await resolveDisconnectCause(fake as never)).toBe('crash');
  });

  it('clean: process exits asynchronously with code 0 within timeout', async () => {
    const { resolveDisconnectCause } = await import('../src/browser-manager');
    const fake = makeFakeBrowser({ exitCode: 0, signalCode: null, exitDelay: 50 });
    expect(await resolveDisconnectCause(fake as never)).toBe('clean');
  });

  it('crash: process exits asynchronously with non-zero code', async () => {
    const { resolveDisconnectCause } = await import('../src/browser-manager');
    const fake = makeFakeBrowser({ exitCode: 137, signalCode: null, exitDelay: 50 });
    expect(await resolveDisconnectCause(fake as never)).toBe('crash');
  });

  it('crash: null browser returns crash (defensive default)', async () => {
    const { resolveDisconnectCause } = await import('../src/browser-manager');
    expect(await resolveDisconnectCause(null)).toBe('crash');
  });
});