import { afterEach, describe, expect, it, vi } from 'vitest';

type InitModule = typeof import('./init');

async function loadInitModule(): Promise<InitModule> {
  vi.resetModules();
  return import('./init');
}

function createSdkFactory() {
  const calls: Array<Record<string, unknown>> = [];
  const getTracerProvider = vi.fn(() => ({ id: 'mock-tracer-provider' }));
  const start = vi.fn();
  const shutdown = vi.fn(async () => {});

  return {
    calls,
    getTracerProvider,
    start,
    shutdown,
    sdkFactory: (options: Record<string, unknown>) => {
      calls.push(options);
      return {
        start,
        shutdown,
        getTracerProvider,
      } as never;
    },
  };
}

describe('init() OpenLLMetry integration', () => {
  afterEach(() => {
    vi.clearAllMocks();
    delete process.env.AUTOTEL_METRICS;
    delete process.env.NODE_ENV;
    delete process.env.TRACELOOP_API_KEY;
  });

  it('should not initialize OpenLLMetry when disabled', async () => {
    const mod = await loadInitModule();
    const sdk = createSdkFactory();
    const traceloopInitializeCalls: Array<Record<string, unknown>> = [];

    mod._setOptionalRequireForTesting(() => ({
      initialize: (options?: Record<string, unknown>) =>
        traceloopInitializeCalls.push(options ?? {}),
    }));

    mod.init({ service: 'test-app', sdkFactory: sdk.sdkFactory });

    expect(traceloopInitializeCalls).toHaveLength(0);
    mod._resetOptionalRequireForTesting();
  });

  it('should initialize OpenLLMetry when enabled', async () => {
    const mod = await loadInitModule();
    const sdk = createSdkFactory();
    const traceloopInitializeCalls: Array<Record<string, unknown>> = [];

    mod._setOptionalRequireForTesting(() => ({
      initialize: (options?: Record<string, unknown>) =>
        traceloopInitializeCalls.push(options ?? {}),
    }));

    mod.init({
      service: 'test-app',
      openllmetry: { enabled: true },
      sdkFactory: sdk.sdkFactory,
    });

    expect(traceloopInitializeCalls).toHaveLength(1);
    expect(traceloopInitializeCalls[0]).toBeDefined();
    mod._resetOptionalRequireForTesting();
  });

  it('should pass OpenLLMetry options to initialize', async () => {
    const mod = await loadInitModule();
    const sdk = createSdkFactory();
    const traceloopInitializeCalls: Array<Record<string, unknown>> = [];

    mod._setOptionalRequireForTesting(() => ({
      initialize: (options?: Record<string, unknown>) =>
        traceloopInitializeCalls.push(options ?? {}),
    }));

    mod.init({
      service: 'test-app',
      openllmetry: {
        enabled: true,
        options: {
          disableBatch: true,
          apiKey: 'test-key',
        },
      },
      sdkFactory: sdk.sdkFactory,
    });

    expect(traceloopInitializeCalls).toHaveLength(1);
    expect(traceloopInitializeCalls[0]).toMatchObject({
      disableBatch: true,
      apiKey: 'test-key',
    });
    mod._resetOptionalRequireForTesting();
  });

  it('should reuse autotel tracer provider when OpenLLMetry is enabled', async () => {
    const mod = await loadInitModule();
    const sdk = createSdkFactory();
    const traceloopInitializeCalls: Array<Record<string, unknown>> = [];

    mod._setOptionalRequireForTesting(() => ({
      initialize: (options?: Record<string, unknown>) =>
        traceloopInitializeCalls.push(options ?? {}),
    }));

    mod.init({
      service: 'test-app',
      openllmetry: { enabled: true },
      sdkFactory: sdk.sdkFactory,
    });

    expect(traceloopInitializeCalls).toHaveLength(1);
    const callOptions = traceloopInitializeCalls[0];
    expect(callOptions).toBeDefined();
    expect(sdk.getTracerProvider).toHaveBeenCalled();
    mod._resetOptionalRequireForTesting();
  });

  it('should add OpenLLMetry instrumentations when selectiveInstrumentation is false', async () => {
    const mod = await loadInitModule();
    const sdk = createSdkFactory();
    const mockTraceloop = {
      initialize: vi.fn(),
      instrumentations: [{ name: 'openai' }, { name: 'langchain' }],
    };

    mod._setOptionalRequireForTesting(() => mockTraceloop);

    mod.init({
      service: 'test-app',
      openllmetry: { enabled: true },
      autoInstrumentations: false,
      sdkFactory: sdk.sdkFactory,
    });

    const options = sdk.calls.at(-1) as Record<string, unknown>;
    const instrumentations = options.instrumentations as unknown[];

    expect(instrumentations).toBeDefined();
    expect(mockTraceloop.instrumentations).toBeDefined();
    mod._resetOptionalRequireForTesting();
  });

  it('should handle missing @traceloop/node-server-sdk gracefully', async () => {
    const mod = await loadInitModule();
    const sdk = createSdkFactory();
    mod._setOptionalRequireForTesting(() => undefined);

    expect(() => {
      mod.init({
        service: 'test-app',
        openllmetry: { enabled: true },
        sdkFactory: sdk.sdkFactory,
      });
    }).not.toThrow();
    mod._resetOptionalRequireForTesting();
  });

  it('should initialize OpenLLMetry after SDK start', async () => {
    const mod = await loadInitModule();
    const sdk = createSdkFactory();
    const traceloopInitializeCalls: Array<Record<string, unknown>> = [];

    mod._setOptionalRequireForTesting(() => ({
      initialize: (options?: Record<string, unknown>) =>
        traceloopInitializeCalls.push(options ?? {}),
    }));

    mod.init({
      service: 'test-app',
      openllmetry: { enabled: true },
      sdkFactory: sdk.sdkFactory,
    });

    // Verify SDK started (synchronously in init)
    expect(sdk.calls).toHaveLength(1);
    expect(sdk.start).toHaveBeenCalled();

    // Verify OpenLLMetry was initialized (synchronously via safeRequire)
    expect(traceloopInitializeCalls).toHaveLength(1);
    mod._resetOptionalRequireForTesting();
  });
});