import { Logger } from '@nestjs/common';
import type { NestExpressApplication } from '@nestjs/platform-express';
import {
  configureApp,
  describeTrustProxy,
  trustProxySetting,
} from './app.config';

describe('trustProxySetting', () => {
  const original = process.env.TRUST_PROXY;
  afterEach(() => {
    if (original === undefined) delete process.env.TRUST_PROXY;
    else process.env.TRUST_PROXY = original;
  });

  it('defaults to one hop when unset or blank', () => {
    delete process.env.TRUST_PROXY;
    expect(trustProxySetting()).toBe(1);
    process.env.TRUST_PROXY = '  ';
    expect(trustProxySetting()).toBe(1);
  });

  it('parses a number as hop count and anything else as a list', () => {
    process.env.TRUST_PROXY = '2';
    expect(trustProxySetting()).toBe(2);
    process.env.TRUST_PROXY = 'loopback, 10.42.0.0/16';
    expect(trustProxySetting()).toBe('loopback, 10.42.0.0/16');
  });
});

describe('describeTrustProxy', () => {
  it('reports the hop count mode and the default fallback', () => {
    expect(describeTrustProxy(1, false)).toBe(
      'TRUST_PROXY not set, using default of 1 trusted hop',
    );
    expect(describeTrustProxy(2, true)).toBe('TRUST_PROXY: 2 trusted hop(s)');
  });

  it('reports the list mode with entry count but not the entries', () => {
    const text = describeTrustProxy(
      'loopback, 10.42.0.0/16, 2400:cb00::/32',
      true,
    );
    expect(text).toBe('TRUST_PROXY: list of 3 trusted proxy range(s)');
  });
});

describe('configureApp trust proxy logging', () => {
  it('logs the active mode once at startup', () => {
    const log = jest.spyOn(Logger.prototype, 'log').mockImplementation();
    const app = {
      set: jest.fn(),
      useBodyParser: jest.fn(),
      use: jest.fn(),
      useGlobalFilters: jest.fn(),
      enableCors: jest.fn(),
      setGlobalPrefix: jest.fn(),
      enableVersioning: jest.fn(),
      useGlobalPipes: jest.fn(),
    };
    configureApp(app as unknown as NestExpressApplication);
    expect(
      log.mock.calls.filter(([m]) => String(m).startsWith('TRUST_PROXY')),
    ).toHaveLength(1);
    log.mockRestore();
  });
});

describe('configureApp trust proxy warning', () => {
  const originalProxy = process.env.TRUST_PROXY;
  const originalEnv = process.env.NODE_ENV;
  afterEach(() => {
    if (originalProxy === undefined) delete process.env.TRUST_PROXY;
    else process.env.TRUST_PROXY = originalProxy;
    if (originalEnv === undefined) delete process.env.NODE_ENV;
    else process.env.NODE_ENV = originalEnv;
  });

  function configure(): jest.SpyInstance {
    const warn = jest.spyOn(Logger.prototype, 'warn').mockImplementation();
    jest.spyOn(Logger.prototype, 'log').mockImplementation();
    const app = {
      set: jest.fn(),
      useBodyParser: jest.fn(),
      use: jest.fn(),
      useGlobalFilters: jest.fn(),
      enableCors: jest.fn(),
      setGlobalPrefix: jest.fn(),
      enableVersioning: jest.fn(),
      useGlobalPipes: jest.fn(),
    };
    configureApp(app as unknown as NestExpressApplication);
    return warn;
  }

  function trustProxyWarnings(warn: jest.SpyInstance): unknown[][] {
    const calls = warn.mock.calls as unknown[][];
    return calls.filter(([m]) => String(m).includes('TRUST_PROXY'));
  }

  afterEach(() => jest.restoreAllMocks());

  it('warnt in Produktion, wenn TRUST_PROXY fehlt', () => {
    process.env.NODE_ENV = 'production';
    delete process.env.TRUST_PROXY;
    expect(trustProxyWarnings(configure())).toHaveLength(1);
  });

  it('warnt nicht, wenn TRUST_PROXY gesetzt ist', () => {
    process.env.NODE_ENV = 'production';
    process.env.TRUST_PROXY = 'loopback, 10.42.0.0/16';
    expect(trustProxyWarnings(configure())).toHaveLength(0);
  });

  it('warnt nicht in der Entwicklung', () => {
    process.env.NODE_ENV = 'development';
    delete process.env.TRUST_PROXY;
    expect(trustProxyWarnings(configure())).toHaveLength(0);
  });
});