using System;
using System.Collections.Generic;
using System.Globalization;
using System.Reflection;
using System.Resources;
using System.Threading;

namespace MonoGameBlank2dStartKit.Core.Localization;

/// <summary>
/// Manages localization settings for the game, including retrieving supported cultures and setting the current culture for localization.
/// </summary>
internal class LocalizationManager
{
    /// <summary>
    /// the culture code we default to
    /// </summary>
    public const string DEFAULT_CULTURE_CODE = "en-EN";

    /// <summary>
    /// Retrieves a list of supported cultures based on available language resources in the game.
    /// This method checks the current culture settings and the satellite assemblies for available localized resources.
    /// </summary>
    /// <returns>A list of <see cref="CultureInfo"/> objects representing the cultures supported by the game.</returns>
    /// <remarks>
    /// This method iterates through all specific cultures defined in the satellite assemblies and attempts to load the corresponding resource set.
    /// If a resource set is found for a particular culture, that culture is added to the list of supported cultures. The invariant culture
    /// is always included in the returned list as it represents the default (non-localized) resources.
    /// </remarks>
    public static List<CultureInfo> GetSupportedCultures()
    {
        // Create a list to hold supported cultures
        List<CultureInfo> supportedCultures = new List<CultureInfo>();

        // Get the current assembly
        Assembly assembly = Assembly.GetExecutingAssembly();

        // Resource manager for your Resources.resx
        ResourceManager resourceManager =
            new ResourceManager("MonoGameBlank2dStartKit.Core.Localization.Resources", assembly);

        // Get all cultures defined in the satellite assemblies
        CultureInfo[] cultures = CultureInfo.GetCultures(CultureTypes.SpecificCultures);

        foreach (CultureInfo culture in cultures)
        {
            try
            {
                // Try to get the resource set for this culture
                var resourceSet = resourceManager.GetResourceSet(culture, true, false);
                if (resourceSet != null)
                {
                    supportedCultures.Add(culture);
                }
            }
            catch (MissingManifestResourceException)
            {
                // This exception is thrown when there is no .resx for the culture, ignore it
            }
        }

        // Always add the default (invariant) culture - the base .resx file
        supportedCultures.Add(CultureInfo.InvariantCulture);

        return supportedCultures;
    }

    /// <summary>
    /// Sets the current culture of the game based on the specified culture code.
    /// This method updates both the current culture and UI culture for the current thread.
    /// </summary>
    /// <param name="cultureCode">The culture code (e.g., "en-US", "fr-FR") to set for the game.</param>
    /// <remarks>
    /// This method modifies the <see cref="Thread.CurrentThread.CurrentCulture"/> and <see cref="Thread.CurrentThread.CurrentUICulture"/> properties,
    /// which affect how dates, numbers, and other culture-specific values are formatted, as well as how localized resources are loaded.
    /// </remarks>
    public static void SetCulture(string cultureCode)
    {
        if (string.IsNullOrEmpty(cultureCode))
            throw new ArgumentNullException(nameof(cultureCode), "A culture code must be provided.");

        // Create a CultureInfo object from the culture code
        CultureInfo culture = new CultureInfo(cultureCode);

        // Set the current culture and UI culture for the current thread
        Thread.CurrentThread.CurrentCulture = culture;
        Thread.CurrentThread.CurrentUICulture = culture;
    }
}