/**
 * i18n PR1 - country dataset.
 *
 * Validates:
 *  1. The dataset includes every common ISO-3166-1 alpha-2 code we'd
 *     reasonably want (sanity sample, not exhaustive)
 *  2. `isValidCountryCode` rejects bogus inputs
 *  3. `getCountryName` returns localized names; falls back to the code
 *  4. `detectDefaultCountry` returns the fallback in non-browser envs
 */

import { describe, it, expect } from 'vitest';
import {
  ALL_COUNTRY_CODES,
  ISO_COUNTRIES,
  isValidCountryCode,
  getCountryName,
  detectDefaultCountry,
} from '@/lib/i18n/countries';

describe('i18n countries', () => {
  it('includes core anglophone, EU, MENA, APAC, and Americas codes', () => {
    const sample = ['US', 'GB', 'PL', 'DE', 'FR', 'AU', 'JP', 'BR', 'AE', 'NG', 'AI'];
    for (const code of sample) {
      expect(ISO_COUNTRIES.has(code)).toBe(true);
    }
  });

  it('has at least 240 codes and is unique', () => {
    expect(ALL_COUNTRY_CODES.length).toBeGreaterThanOrEqual(240);
    expect(new Set(ALL_COUNTRY_CODES).size).toBe(ALL_COUNTRY_CODES.length);
  });

  it('isValidCountryCode rejects unknown / lowercased / 3-letter codes', () => {
    expect(isValidCountryCode('US')).toBe(true);
    expect(isValidCountryCode('us')).toBe(false);
    expect(isValidCountryCode('USA')).toBe(false);
    expect(isValidCountryCode('XX')).toBe(false);
    expect(isValidCountryCode('')).toBe(false);
  });

  it('getCountryName returns localized names and falls back to the code on error', () => {
    expect(getCountryName('US', 'en')).toMatch(/United States/);
    expect(getCountryName('GB', 'en')).toMatch(/United Kingdom/);
    expect(getCountryName('PL', 'pl')).toMatch(/Polska/i);
    // Unknown code -> code itself.
    expect(getCountryName('ZZ', 'en')).toBe('ZZ');
  });

  it('detectDefaultCountry returns the navigator region when valid', () => {
    const original = globalThis.navigator;
    Object.defineProperty(globalThis, 'navigator', {
      value: { language: 'en-GB' },
      configurable: true,
    });
    expect(detectDefaultCountry()).toBe('GB');
    Object.defineProperty(globalThis, 'navigator', {
      value: original,
      configurable: true,
    });
  });

  it('detectDefaultCountry uses the fallback when navigator is unset', () => {
    const original = globalThis.navigator;
    // @ts-expect-error force navigator to undefined for the duration of this test
    delete globalThis.navigator;
    expect(detectDefaultCountry()).toBe('US');
    expect(detectDefaultCountry('GB')).toBe('GB');
    Object.defineProperty(globalThis, 'navigator', {
      value: original,
      configurable: true,
    });
  });

  it('detectDefaultCountry falls back when the navigator region is unknown', () => {
    const original = globalThis.navigator;
    Object.defineProperty(globalThis, 'navigator', {
      value: { language: 'xx-ZZ' },
      configurable: true,
    });
    expect(detectDefaultCountry()).toBe('US');
    Object.defineProperty(globalThis, 'navigator', {
      value: original,
      configurable: true,
    });
  });
});
