import { describe, it, expect, vi, afterEach } from 'vitest';
import * as net from 'node:net';
import type { Logger } from 'pino';
import type { Adapter, AdapterContext, Metrics, Position } from '../../src/core/types.js';
import { startServer } from '../../src/core/server.js';

function makeMockContext(): AdapterContext {
  const logger = {
    debug: vi.fn(),
    info: vi.fn(),
    warn: vi.fn(),
    error: vi.fn(),
    child: vi.fn().mockReturnThis(),
  } as unknown as Logger;

  const metrics: Metrics = {
    inc: vi.fn(),
    observe: vi.fn(),
  };

  return {
    publish: vi.fn(async (_p: Position) => {}),
    logger,
    metrics,
  };
}

describe('startServer', () => {
  const servers: net.Server[] = [];

  afterEach(() => {
    for (const server of servers) {
      server.close();
    }
    servers.length = 0;
  });

  it('invokes handleSession with a real socket when a client connects', async () => {
    const handleSession = vi.fn().mockResolvedValue(undefined);

    const adapter: Adapter = {
      name: 'test-adapter',
      ports: [0], // port 0 = OS-assigned ephemeral port
      handleSession,
    };

    const ctx = makeMockContext();
    const server = startServer(0, adapter, ctx);
    servers.push(server);

    // Wait for the server to start listening
    const port = await new Promise<number>((resolve) => {
      server.on('listening', () => {
        const addr = server.address();
        resolve(typeof addr === 'object' && addr !== null ? addr.port : 0);
      });
    });

    // Connect a client
    const client = new net.Socket();
    client.connect(port, '127.0.0.1');

    // Wait for handleSession to be called
    await vi.waitFor(() => expect(handleSession).toHaveBeenCalledOnce(), { timeout: 2000 });

    const [socketArg, ctxArg] = handleSession.mock.calls[0] as [net.Socket, AdapterContext];
    expect(socketArg).toBeInstanceOf(net.Socket);
    expect(ctxArg).toBeDefined();
    expect(typeof ctxArg.publish).toBe('function');
    expect(ctxArg.logger).toBeDefined();

    client.destroy();
  });
});