VRCMelonAssistant/VRCMelonAssistant/Classes/Languages.cs

using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Windows;
using VRCMelonAssistant.Pages;

namespace VRCMelonAssistant
{
    class Languages
    {
        public static string LoadedLanguage { get; private set; }
        public static List<CultureInfo> LoadedLanguages { get => availableCultures.ToList(); }
        public static bool FirstRun = true;
        private static readonly string[] availableLanguageCodes = { "en" };
        private static IEnumerable<CultureInfo> availableCultures;

        public static void LoadLanguages()
        {
            var allCultures = CultureInfo.GetCultures(CultureTypes.AllCultures);

            // Get CultureInfo for any of the available translations
            availableCultures = allCultures.Where(cultureInfo => availableLanguageCodes.Any(code => code.Equals(cultureInfo.Name)));

            string savedLanguageCode = Properties.Settings.Default.LanguageCode;
            if (!LoadLanguage(savedLanguageCode))
            {
                // If no language code was saved, load system language
                if (!LoadLanguage(CultureInfo.CurrentUICulture.Name))
                {
                    LoadLanguage("en");
                }
            }
            UpdateUI(LoadedLanguage);
        }

        public static void UpdateUI(string languageCode)
        {
            if (Options.Instance != null && Options.Instance.LanguageSelectComboBox != null)
            {
                Options.Instance.LanguageSelectComboBox.ItemsSource = availableCultures.Select(cultureInfo => cultureInfo.NativeName).ToList();
                Options.Instance.LanguageSelectComboBox.SelectedIndex = LoadedLanguages.FindIndex(cultureInfo => cultureInfo.Name.Equals(languageCode));
            }
        }

        public static ResourceDictionary LanguagesDict
        {
            get
            {
                return Application.Current.Resources.MergedDictionaries[1];
            }
        }

        public static bool LoadLanguage(string languageCode)
        {
            if (string.IsNullOrEmpty(languageCode)) return false;
            try
            {
                LanguagesDict.Source = new Uri($"Localisation/{languageCode}.xaml", UriKind.Relative);
                LoadedLanguage = languageCode;
                return true;
            }
            catch (IOException)
            {
                if (languageCode.Contains("-"))
                {
                    return LoadLanguage(languageCode.Split('-').First());
                }
                return false;
            }
        }
    }
}