#nullable enable
using System.Net.Security;

namespace gehGassiApp.Core.Helper
{
    /// <summary>
    /// Hilfsklasse für das lokale Debugging.
    /// Ermöglicht den Zugriff auf die lokal REST-API
    /// </summary>
    public class DevHttpsConnectionHelper
    {
        /// <summary>
        /// Erstellt eine Instanz
        /// </summary>
        /// <param name="sslPort">Port</param>
        public DevHttpsConnectionHelper(int sslPort)
        {
            SslPort = sslPort;
            DevServerRootUrl = FormattableString.Invariant($"https://{DevServerName}:{SslPort}");
#if WINDOWS
            LazyHttpClient = new Lazy<HttpClient>(() => new HttpClient());
#else
            LazyHttpClient = new Lazy<HttpClient>(() => new HttpClient(GetPlatformMessageHandler()));
#endif
            
        }

        public int SslPort { get; }

        public string DevServerName =>
#if WINDOWS
        "localhost";
#elif ANDROID
        "192.168.0.172";
#elif IOS || MACCATALYST
        "192.168.0.172";
#else
        throw new PlatformNotSupportedException("Only Windows and Android currently supported.");
#endif

        public string DevServerRootUrl { get; }

        private Lazy<HttpClient> LazyHttpClient;
        public HttpClient HttpClient => LazyHttpClient.Value;

        public HttpMessageHandler? GetPlatformMessageHandler()
        {
#if WINDOWS
        return null;
#elif IOS || MACCATALYST
            var handler = new NSUrlSessionHandler
            {
                TrustOverrideForUrl = IsHttpsLocalhost
            };
            return handler;
#elif ANDROID
            var handler = new CustomAndroidMessageHandler();
            handler.ServerCertificateCustomValidationCallback = (message, cert, chain, errors) =>
            {
                if (cert != null && cert.Issuer.Equals("CN=localhost"))
                    return true;
                return errors == SslPolicyErrors.None;
            };
            return handler;

#else
            throw new PlatformNotSupportedException("Only Windows and Android currently supported.");
#endif
        }

#if ANDROID
        internal sealed class CustomAndroidMessageHandler : Xamarin.Android.Net.AndroidMessageHandler
        {
            protected override Javax.Net.Ssl.IHostnameVerifier GetSSLHostnameVerifier(Javax.Net.Ssl.HttpsURLConnection connection)
                => new CustomHostnameVerifier();

            private sealed class CustomHostnameVerifier : Java.Lang.Object, Javax.Net.Ssl.IHostnameVerifier
            {
                public bool Verify(string? hostname, Javax.Net.Ssl.ISSLSession? session)
                {
                    return
                        Javax.Net.Ssl.HttpsURLConnection.DefaultHostnameVerifier.Verify(hostname, session)
                        || hostname == "192.168.0.172" && session.PeerPrincipal?.Name == "CN=localhost";
                }
            }
        }
#elif IOS || MACCATALYST
    public bool IsHttpsLocalhost(NSUrlSessionHandler sender, string url, Security.SecTrust trust)
    {
        if (url.StartsWith("https://localhost") || url.StartsWith("https://192.168.0.172"))
            return true;
        return false;
    }
#endif
    }

    public static class DevHttpsConnectionHelperExtensions
    {
        public static IServiceCollection AddDevHttpClient(this IServiceCollection services, int sslPort)
        {
            var devSslHelper = new DevHttpsConnectionHelper(sslPort);
            var http = devSslHelper.HttpClient;
            http.BaseAddress = new Uri(devSslHelper.DevServerRootUrl);
            services.AddScoped(sp => http);
            return services;
        }
    }
}