PrepareAssets.cs

private static string _localWadPath;

/// <summary>
/// Prepares assets for WebAssembly by downloading them via HTTP
/// </summary>
public static async Task PrepareAssetsAsync()
{
    var localFolder = await ApplicationData.Current.LocalFolder.CreateFolderAsync("Wads", CreationCollisionOption.OpenIfExists);
    foreach (var name in iwadNames)
    {
        var assetPath = $"Assets/{name}";
        try
        {
            var fileFromAssets = await StorageFile.GetFileFromApplicationUriAsync(new Uri($"ms-appx:///{assetPath}"));
            if (fileFromAssets != null)
            {
                // Copy to local folder
                var existingFile = await localFolder.TryGetItemAsync(name);
                if (existingFile != null)
                {
                    _localWadPath = existingFile.Path;
                    Console.WriteLine($"IWAD {name} already exists in local folder.");
                    break;
                } else
                {
                    var copiedFile = await fileFromAssets.CopyAsync(localFolder, name, NameCollisionOption.ReplaceExisting);
                    Console.WriteLine($"Copied IWAD {name} to local folder.");
                    _localWadPath = copiedFile.Path;
                }
            }
        }
        catch
        {
            // Ignore missing assets
        }
    }
}