#[cfg(not(feature = "without_async"))]
pub mod AsyncUsed
{
    use std::num::NonZeroU32;

    #[cfg(not(feature = "std"))]
    extern crate alloc;

    use scram_rs::AsyncScramAuthClient;
    use scram_rs::AsyncScramAuthServer;
    use scram_rs::AsyncScramCbHelper;
    use scram_rs::ScramResult;
    use scram_rs::ScramResultClient;
    use scram_rs::ScramSha256RustNative;
    use scram_rs::ScramNonce;
    use scram_rs::ScramPassword;
    use scram_rs::async_trait;
    use scram_rs::scram_async::AsyncScramClient;
    use scram_rs::scram_async::AsyncScramServer;
    use scram_rs::SCRAM_TYPES;

    #[derive(Debug)]
    struct AuthDB
    {
    }

    impl AuthDB
    {
        pub fn new() -> Self
        {
            return AuthDB{};
        }
    }

    #[async_trait]
    impl AsyncScramCbHelper for &AuthDB
    {
        async 
        fn get_tls_server_endpoint(&self) -> ScramResult<Vec<u8>> 
        {
            scram_rs::HELPER_UNSUP_SERVER!("endpoint");
        }

        async 
        fn get_tls_unique(&self) -> ScramResult<Vec<u8>> {
            scram_rs::HELPER_UNSUP_SERVER!("unique");
        }

        async 
        fn get_tls_exporter(&self) -> ScramResult<Vec<u8>> 
        {
            scram_rs::HELPER_UNSUP_SERVER!("exporter");
        }
    }

    #[async_trait]
    impl AsyncScramAuthServer<ScramSha256RustNative> for &AuthDB
    {
        async 
        fn get_password_for_user(&self, username: &str) -> ScramResult<ScramPassword>
        {
            return 
                if username == "user"
                {
                    Ok(ScramPassword::found_secret_base64_password(
                        "xeR41ZKIyEGqUw22hFxMjZYok6ABzk4RpJY4c6qYE0o=".to_string(),
                            "c2FsdA==".to_string(), 
                            unsafe { NonZeroU32::new_unchecked(4096) },
                        None
                    )?)
                }
                else 
                {
                    ScramPassword::not_found::<ScramSha256RustNative>()
                };       
        }
    }

    #[derive(Debug)]
    struct AuthClient
    {
        username: String,
        password: String,
        key: scram_rs::ScramKey,
    }

    #[async_trait]
    impl AsyncScramCbHelper for &AuthClient
    {
        async 
        fn get_tls_server_endpoint(&self) -> ScramResult<Vec<u8>> 
        {
            scram_rs::HELPER_UNSUP_CLIENT!("endpoint");
        }

        async 
        fn get_tls_unique(&self) -> ScramResult<Vec<u8>> {
            scram_rs::HELPER_UNSUP_CLIENT!("unique");
        }

        async 
        fn get_tls_exporter(&self) -> ScramResult<Vec<u8>> 
        {
            scram_rs::HELPER_UNSUP_CLIENT!("exporter");
        }
    }

    #[async_trait]
    impl AsyncScramAuthClient for &AuthClient
    {
        async fn get_username(&self) -> &str
        {
            return &self.username;
        }

        async fn get_password(&self) -> &str
        {
            return &self.password;
        }

        async fn get_scram_keys(&self) -> &scram_rs::ScramKey 
        {
            return &self.key;
        }
    }

    impl AuthClient
    {
        pub 
        fn new(u: &'static str, p: &'static str) -> Self
        {
            return AuthClient{ username: u.to_string(), password: p.to_string(), key: scram_rs::ScramKey::new() };
        }
    }

    /// This example will not run, because it requires server, see tests in scram_sync.rs
    pub fn main1()
    {
        tokio::runtime::Builder::new_multi_thread()
            .enable_all()
            .build()
            .unwrap()
            .block_on(async 
            {
                let client = AuthClient::new("user5", "password44");
        
                let (clie_send, mut serv_recv) = tokio::sync::mpsc::unbounded_channel::<String>();
                let (serv_send, mut clie_recv) = tokio::sync::mpsc::unbounded_channel::<String>();

                let hndl = 
                    tokio::spawn(async move 
                        {
                            let authdb = AuthDB::new();
                            let scramtype = SCRAM_TYPES.get_scramtype("SCRAM-SHA-256").unwrap();
                        
                            let mut server = 
                                AsyncScramServer::<ScramSha256RustNative, &AuthDB, &AuthDB>::new(&authdb, &authdb, ScramNonce::none(), scramtype).unwrap();
                        
                            loop
                            {
                                let client_data = serv_recv.recv().await.unwrap();

                                let serv_data = server.parse_response_base64(client_data).await;
                                serv_send.send(serv_data.encode_base64()).unwrap();

                                match serv_data
                                {
                                    scram_rs::ScramResultServer::Error(e) => 
                                    {
                                        println!("server: error: {}", e);
                                        break;
                                    },
                                    scram_rs::ScramResultServer::Final(_) =>
                                    {
                                        println!("server: final!");
                                        break;
                                    },
                                    _ => {}
                                }
                            }
                        }
                    );

                let mut client =
                    AsyncScramClient
                        ::<ScramSha256RustNative, &AuthClient, &AuthClient>
                        ::new(&client, ScramNonce::None, scram_rs::ChannelBindType::None, &client)
                            .unwrap();

                // client sends initial message: cli -> serv
                let ci = client.init_client().await.encode_output_base64().unwrap();
                clie_send.send(ci).unwrap();

                
                loop
                {
                    let serv_data = clie_recv.recv().await.unwrap();

                    match client.parse_response_base64(serv_data).await
                    {
                        Ok(ScramResultClient::Completed) => 
                        {
                            println!("client: completed auth successfully");
                            break;
                        },
                        Ok(out) => clie_send.send(out.encode_output_base64().unwrap()).unwrap(),
                        Err(e) =>
                        {
                            println!("client: error: {}", e);
                            break;
                        }
                    }

                }

                hndl.await.unwrap();

                return;
            }
        );

        
    }
}


#[cfg(not(feature = "without_async"))]
use self::AsyncUsed::*;


/// This example will not run, because it requires server, see tests in scram_sync.rs
pub fn main()
{
    #[cfg(not(feature = "without_async"))]
    main1();

    #[cfg(feature = "without_async")]
    eprintln!("Ring support was not enabled!");
}