import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
import { registerShutdownHandler } from "../../src/shutdown-handler.js";

describe("registerShutdownHandler", () => {
  let mockGateway: { shutdown: ReturnType<typeof vi.fn> };
  let sigintListeners: Array<() => void>;
  let sigtermListeners: Array<() => void>;

  beforeEach(() => {
    mockGateway = { shutdown: vi.fn() };
    sigintListeners = [];
    sigtermListeners = [];

    vi.spyOn(process, "on").mockImplementation((event: string, listener: (...args: unknown[]) => void) => {
      if (event === "SIGINT") sigintListeners.push(listener as () => void);
      if (event === "SIGTERM") sigtermListeners.push(listener as () => void);
      return process;
    });
    vi.spyOn(console, "log").mockImplementation(() => {});
  });

  afterEach(() => {
    vi.restoreAllMocks();
  });

  it("registers listeners for SIGTERM and SIGINT", () => {
    registerShutdownHandler(mockGateway as never);
    expect(sigtermListeners).toHaveLength(1);
    expect(sigintListeners).toHaveLength(1);
  });

  it("calls gateway.shutdown() on SIGTERM", () => {
    registerShutdownHandler(mockGateway as never);
    sigtermListeners[0]();
    expect(mockGateway.shutdown).toHaveBeenCalledOnce();
  });

  it("calls gateway.shutdown() on SIGINT", () => {
    registerShutdownHandler(mockGateway as never);
    sigintListeners[0]();
    expect(mockGateway.shutdown).toHaveBeenCalledOnce();
  });

  it("prevents double-shutdown on repeated signals", () => {
    registerShutdownHandler(mockGateway as never);
    sigtermListeners[0]();
    sigintListeners[0]();
    sigtermListeners[0]();
    expect(mockGateway.shutdown).toHaveBeenCalledOnce();
  });

  it("logs the signal name", () => {
    registerShutdownHandler(mockGateway as never);
    sigtermListeners[0]();
    expect(console.log).toHaveBeenCalledWith("Received SIGTERM, shutting down...");
  });
});