Locale Management

/**
 * Register locale data for browser environment
 * @param localeData - Object containing locale identifier and country name mappings
 * @throws TypeError if localeData.locale or localeData.countries is missing
 */
function registerLocale(localeData: LocaleData): void;

interface LocaleData {
  locale: string;
  countries: { [alpha2Key: string]: string | string[] };
}

const countries = require("i18n-iso-countries");

// Register English locale
countries.registerLocale(require("i18n-iso-countries/langs/en.json"));

// Register multiple locales
countries.registerLocale(require("i18n-iso-countries/langs/fr.json"));
countries.registerLocale(require("i18n-iso-countries/langs/de.json"));
countries.registerLocale(require("i18n-iso-countries/langs/es.json"));

// Now you can use name functions
console.log(countries.getName("US", "en"));  // "United States of America"
console.log(countries.getName("US", "fr"));  // "États-Unis"
console.log(countries.getName("US", "de"));  // "Vereinigte Staaten von Amerika"

// Custom locale data registration
const customLocale = {
  locale: "test",
  countries: {
    "US": "Test United States",
    "GB": ["Test United Kingdom", "Test UK"],
    "DE": "Test Germany"
  }
};
countries.registerLocale(customLocale);
console.log(countries.getName("US", "test")); // "Test United States"
console.log(countries.getName("GB", "test", { select: "alias" })); // "Test UK"

const countries = require("i18n-iso-countries");

// Missing locale property
try {
  countries.registerLocale({
    countries: { "US": "United States" }
  });
} catch (error) {
  console.log(error.message); // "Missing localeData.locale"
}

// Missing countries property
try {
  countries.registerLocale({
    locale: "en"
  });
} catch (error) {
  console.log(error.message); // "Missing localeData.countries"
}

// Invalid structure - countries must be an object
try {
  countries.registerLocale({
    locale: "en",
    countries: "invalid"
  });
} catch (error) {
  console.log(error.message); // "Missing localeData.countries"
}

/**
 * Get all supported language codes
 * @returns Array of ISO 639-1 language codes supported by the library
 */
function getSupportedLanguages(): string[];

const countries = require("i18n-iso-countries");

const supportedLangs = countries.getSupportedLanguages();

console.log(supportedLangs.length); // 79

// Check if a language is supported
function isLanguageSupported(langCode) {
  return supportedLangs.includes(langCode);
}

console.log(isLanguageSupported("en")); // true
console.log(isLanguageSupported("fr")); // true
console.log(isLanguageSupported("xx")); // false

// Display supported languages
console.log("Supported languages:", supportedLangs.join(", "));
// Output: br, cy, dv, sw, eu, af, am, ha, ku, ml, mt, no, ps, sd, so, sq, ta, tg, tt, ug, ur, vi, ar, az, be, bg, bn, bs, ca, cs, da, de, el, en, es, et, fa, fi, fr, ga, gl, he, hi, hr, hu, hy, id, is, it, ja, ka, kk, km, ko, ky, lt, lv, mk, mn, mr, ms, nb, nl, nn, pl, pt, ro, ru, sk, sl, sr, sv, th, tk, tr, uk, uz, zh

// Iterate through supported languages
supportedLangs.forEach(lang => {
  console.log(`Language: ${lang}`);
});

/**
 * Get currently registered language codes
 * @returns Array of language codes that have been registered in the current session
 */
function langs(): string[];

const countries = require("i18n-iso-countries");

// Initially, in browser environment, no languages are registered
console.log(countries.langs()); // []

// Register some languages
countries.registerLocale(require("i18n-iso-countries/langs/en.json"));
countries.registerLocale(require("i18n-iso-countries/langs/fr.json"));

// Now these languages are available
console.log(countries.langs()); // ["en", "fr"]

// Register more languages
countries.registerLocale(require("i18n-iso-countries/langs/de.json"));
countries.registerLocale(require("i18n-iso-countries/langs/es.json"));

console.log(countries.langs()); // ["en", "fr", "de", "es"]

// Check if specific language is registered
function isLanguageRegistered(langCode) {
  return countries.langs().includes(langCode);
}

console.log(isLanguageRegistered("en")); // true
console.log(isLanguageRegistered("zh")); // false (not registered yet)

const countries = require("i18n-iso-countries");

// All 79 languages are immediately available
console.log(countries.langs().length); // 79
console.log(countries.getSupportedLanguages().length); // 79

// langs() and getSupportedLanguages() return the same list
console.log(countries.langs().sort()); 
console.log(countries.getSupportedLanguages().sort());
// Both return the same 79 language codes

// No registration needed
console.log(countries.getName("US", "zh")); // Works immediately
console.log(countries.getName("US", "ar")); // Works immediately

const countries = require("i18n-iso-countries");

// Initially no languages registered
console.log(countries.langs()); // []
console.log(countries.getSupportedLanguages().length); // 79 (full list available)

// Functions return undefined for unregistered languages
console.log(countries.getName("US", "en")); // undefined

// Register required languages
countries.registerLocale(require("i18n-iso-countries/langs/en.json"));
countries.registerLocale(require("i18n-iso-countries/langs/fr.json"));

// Now registered languages work
console.log(countries.langs()); // ["en", "fr"]
console.log(countries.getName("US", "en")); // "United States of America"
console.log(countries.getName("US", "fr")); // "États-Unis"
console.log(countries.getName("US", "de")); // undefined (not registered)

// Example structure of a locale file (en.json)
const enLocale = {
  "locale": "en",
  "countries": {
    "AF": "Afghanistan",
    "AL": "Albania",
    "DZ": "Algeria",
    // ... more countries with single names
    "GB": ["United Kingdom", "UK", "Great Britain"], // Country with aliases
    // ... more countries
  }
};

// Countries can have either:
// 1. Single name (string): "Germany"
// 2. Multiple names (array): ["United Kingdom", "UK", "Great Britain"]
//    - First element is the official name
//    - Additional elements are aliases

// Bundle size optimization - only load needed languages
const countries = require("i18n-iso-countries");

// Application supports English, French, and Spanish
const supportedAppLanguages = ["en", "fr", "es"];

// Load only required languages
supportedAppLanguages.forEach(lang => {
  countries.registerLocale(require(`i18n-iso-countries/langs/${lang}.json`));
});

// Verify registration
console.log("Loaded languages:", countries.langs());

// Create language validation function
function validateLanguage(langCode) {
  return countries.langs().includes(langCode);
}

async function loadLanguage(langCode) {
  // Check if already registered
  if (countries.langs().includes(langCode)) {
    return true;
  }
  
  // Check if language is supported
  if (!countries.getSupportedLanguages().includes(langCode)) {
    throw new Error(`Language '${langCode}' is not supported`);
  }
  
  try {
    // Dynamically import and register
    const localeData = require(`i18n-iso-countries/langs/${langCode}.json`);
    countries.registerLocale(localeData);
    return true;
  } catch (error) {
    throw new Error(`Failed to load language '${langCode}': ${error.message}`);
  }
}

// Usage
async function getCountryNameWithLazyLoading(countryCode, langCode) {
  await loadLanguage(langCode);
  return countries.getName(countryCode, langCode);
}

// Example
getCountryNameWithLazyLoading("US", "de").then(name => {
  console.log(name); // "Vereinigte Staaten von Amerika"
});

function safeRegisterLocale(langCode) {
  try {
    // Check if already registered
    if (countries.langs().includes(langCode)) {
      return { success: true, message: `Language '${langCode}' already registered` };
    }
    
    // Check if supported
    if (!countries.getSupportedLanguages().includes(langCode)) {
      return { success: false, message: `Language '${langCode}' is not supported` };
    }
    
    // Load and register
    const localeData = require(`i18n-iso-countries/langs/${langCode}.json`);
    countries.registerLocale(localeData);
    
    return { success: true, message: `Language '${langCode}' registered successfully` };
  } catch (error) {
    return { success: false, message: `Failed to register '${langCode}': ${error.message}` };
  }
}

// Usage
console.log(safeRegisterLocale("en")); // { success: true, message: "Language 'en' registered successfully" }
console.log(safeRegisterLocale("xx")); // { success: false, message: "Language 'xx' is not supported" }