@addTagHelper *, DNTCaptcha.Core

using DNTCaptcha.Core;

namespace DNTCaptcha.TestWebApp
{
    public class Startup
    {
        public void ConfigureServices(IServiceCollection services)
        {
	    services.AddDNTCaptcha(options =>
            {		
                // options.UseSessionStorageProvider() // -> It doesn't rely on the server or client's times. Also it's the safest one.
                // options.UseMemoryCacheStorageProvider() // -> It relies on the server's times. It's safer than the CookieStorageProvider.
                options.UseCookieStorageProvider(SameSiteMode.Strict) // -> It relies on the server and client's times. It's ideal for scalability, because it doesn't save anything in the server's memory.
                                                   // .UseDistributedCacheStorageProvider() // --> It's ideal for scalability using `services.AddStackExchangeRedisCache()` for instance.
                                                   // .UseDistributedSerializationProvider()

                // Don't set this line (remove it) to use the installed system's fonts (FontName = "Tahoma").
                // Or if you want to use a custom font, make sure that font is present in the wwwroot/fonts folder and also use a good and complete font!
                .UseCustomFont(Path.Combine(_env.WebRootPath, "fonts", "IRANSans(FaNum)_Bold.ttf")) // This is optional.
                .AbsoluteExpiration(minutes: 7)
                .ShowThousandsSeparators(false)
                .WithNoise(pixelsDensity: 25, linesCount: 3)
                .WithEncryptionKey("This is my secure key!")
                .InputNames(// This is optional. Change it if you don't like the default names.
                    new DNTCaptchaComponent
                    {
                        CaptchaHiddenInputName = "DNTCaptchaText",
                        CaptchaHiddenTokenName = "DNTCaptchaToken",
                        CaptchaInputName = "DNTCaptchaInputText"
                    })
                .Identifier("dntCaptcha")// This is optional. Change it if you don't like its default name.
                ;
     	    });
        }

[HttpPost, ValidateAntiForgeryToken]
[ValidateDNTCaptcha(ErrorMessage = "Please enter the security code as a number.",
                    CaptchaGeneratorLanguage = Language.English,
                    CaptchaGeneratorDisplayMode = DisplayMode.NumberToWord)]
public IActionResult Index([FromForm]AccountViewModel data)
{
    if (ModelState.IsValid) // If `ValidateDNTCaptcha` fails, it will set a `ModelState.AddModelError`.
    {
        //TODO: Save data
        return RedirectToAction(nameof(Thanks), new { name = data.Username });
    }
    return View();
}

namespace DNTCaptcha.TestWebApp.Controllers
{
    public class HomeController : Controller
    {
        private readonly IDNTCaptchaValidatorService _validatorService;
        private readonly DNTCaptchaOptions _captchaOptions;

        public HomeController(IDNTCaptchaValidatorService validatorService, IOptions<DNTCaptchaOptions> options)
        {
            _validatorService = validatorService;
            _captchaOptions = options == null ? throw new ArgumentNullException(nameof(options)) : options.Value;
        }

        [HttpPost, ValidateAntiForgeryToken]
        public IActionResult Login2([FromForm]AccountViewModel data)
        {
            if (!_validatorService.HasRequestValidCaptchaEntry(Language.English, DisplayMode.SumOfTwoNumbersToWords))
            {
                this.ModelState.AddModelError(_captchaOptions.CaptchaComponent.CaptchaInputName, "Please enter the security code as a number.");
                return View(nameof(Index));
            }

            //TODO: Save data
            return RedirectToAction(nameof(Thanks), new { name = data.Username });
        }

services.Configure<ForwardedHeadersOptions>(options =>
{ 
  options.ForwardedHeaders = ForwardedHeaders.XForwardedFor | ForwardedHeaders.XForwardedProto; 
  options.KnownProxies.Add(IPAddress.Parse("my load balancer ip 1")); 
  options.KnownProxies.Add(IPAddress.Parse("my load balancer ip 2")); 
});

services.AddSingleton<ICaptchaImageProvider, MyCustomCaptchaImageProvider>();
services.AddDNTCaptcha();