// file: crates/common/game-realtime-webtransport-lib/unit_tests/webtransport.rs
// version: 4

const TEST_TIMEOUT: std::time::Duration = std::time::Duration::from_secs(3);

#[test]
fn certificate_hash_preserves_exact_sha256_bytes() {
    let bytes = [7_u8; super::CERTIFICATE_HASH_SIZE];
    let hash = super::WebTransportCertificateHash::from_sha256(bytes);
    assert_eq!(hash.as_bytes(), &bytes);
}

#[test]
fn client_config_accepts_https_and_rejects_non_secure_schemes() {
    let hash = super::WebTransportCertificateHash::from_sha256([1_u8; super::CERTIFICATE_HASH_SIZE]);
    let secure = super::WebTransportClientConfig::new("https://127.0.0.1:4433/game", hash.clone());
    assert!(secure.is_ok());
    let insecure_http = super::WebTransportClientConfig::new("http://127.0.0.1:4433/game", hash.clone());
    match insecure_http {
        Ok(_) => panic!("HTTP endpoint unexpectedly accepted"),
        Err(error) => assert_eq!(error.kind(), game_realtime_transport_lib::TransportErrorKind::InvalidConfiguration),
    }
    let websocket = super::WebTransportClientConfig::new("ws://127.0.0.1:4433/game", hash);
    match websocket {
        Ok(_) => panic!("WebSocket endpoint unexpectedly accepted"),
        Err(error) => assert_eq!(error.kind(), game_realtime_transport_lib::TransportErrorKind::InvalidConfiguration),
    }
}

#[test]
fn frame_header_is_big_endian_and_configured_payload_bound_is_enforced() {
    let header = match super::frame_header(0x00_01_02_03, 1024 * 1024) {
        Ok(value) => value,
        Err(error) => panic!("valid frame header rejected: {error}"),
    };
    assert_eq!(header, [0x00, 0x01, 0x02, 0x03]);
    let oversized = super::frame_header(33, 32);
    match oversized {
        Ok(_) => panic!("oversized WebTransport frame unexpectedly accepted"),
        Err(error) => assert_eq!(error.kind(), game_realtime_transport_lib::TransportErrorKind::MessageTooLarge),
    }
}

#[test]
fn stream_error_mapping_distinguishes_abort_close_and_protocol_failures() {
    let stopped = super::map_write_error(web_transport_quinn::WriteError::Stopped(7));
    assert_eq!(stopped.kind(), game_realtime_transport_lib::TransportErrorKind::Aborted);
    let reset = super::map_read_error(web_transport_quinn::ReadError::Reset(8));
    assert_eq!(reset.kind(), game_realtime_transport_lib::TransportErrorKind::Aborted);
    let closed = super::map_read_error(web_transport_quinn::ReadError::SessionError(web_transport_quinn::SessionError::WebTransportError(
        web_transport_quinn::WebTransportError::Closed(9, "done".to_owned()),
    )));
    assert_eq!(closed.kind(), game_realtime_transport_lib::TransportErrorKind::Closed);
    let protocol = super::map_read_error(web_transport_quinn::ReadError::IllegalOrderedRead);
    assert_eq!(protocol.kind(), game_realtime_transport_lib::TransportErrorKind::Protocol);
}

#[test]
fn generated_loopback_identity_has_sha256_fingerprint() {
    let identity = match super::WebTransportServerIdentity::generate_loopback() {
        Ok(value) => value,
        Err(error) => panic!("loopback identity generation failed: {error}"),
    };
    assert_eq!(identity.certificate_hash().as_bytes().len(), super::CERTIFICATE_HASH_SIZE);
}

#[test]
fn injected_identity_rejects_empty_certificate_or_key() {
    let missing_certificate = super::WebTransportServerIdentity::from_pkcs8_der(Vec::new(), vec![1]);
    match missing_certificate {
        Ok(_) => panic!("empty certificate unexpectedly accepted"),
        Err(error) => assert_eq!(error.kind(), game_realtime_transport_lib::TransportErrorKind::InvalidConfiguration),
    }
    let missing_key = super::WebTransportServerIdentity::from_pkcs8_der(vec![1], Vec::new());
    match missing_key {
        Ok(_) => panic!("empty private key unexpectedly accepted"),
        Err(error) => assert_eq!(error.kind(), game_realtime_transport_lib::TransportErrorKind::InvalidConfiguration),
    }
}

#[tokio::test(flavor = "current_thread")]
async fn cancelled_receive_preserves_partial_frame_state() {
    let (server_session, client_session) = establish_private_sessions().await;
    let (mut raw_sender, _raw_receiver) = match client_session.inner.open_bi().await {
        Ok(value) => value,
        Err(error) => panic!("raw client stream open failed: {error}"),
    };
    let (server_sender, server_receiver) = match server_session.inner.accept_bi().await {
        Ok(value) => value,
        Err(error) => panic!("raw server stream accept failed: {error}"),
    };
    let server_connection = super::WebTransportConnection::new(server_session.inner, server_sender, server_receiver, server_session.transport);
    let (_server_sender, mut server_receiver) = game_realtime_transport_lib::RealtimeConnection::split(server_connection);
    if let Err(error) = raw_sender.write_all(&[0x00, 0x00]).await {
        panic!("partial frame header write failed: {error}");
    }
    tokio::time::sleep(std::time::Duration::from_millis(20)).await;
    let first_receive =
        tokio::time::timeout(std::time::Duration::from_millis(100), game_realtime_transport_lib::RealtimeReceiver::receive(&mut server_receiver)).await;
    assert!(first_receive.is_err());
    assert_eq!(server_receiver.header_read, 2);
    if let Err(error) = raw_sender.write_all(&[0x00, 0x03, 0x10, 0x20, 0x30]).await {
        panic!("remaining frame write failed: {error}");
    }
    let second_receive = tokio::time::timeout(TEST_TIMEOUT, game_realtime_transport_lib::RealtimeReceiver::receive(&mut server_receiver)).await;
    match second_receive {
        Ok(Ok(game_realtime_transport_lib::TransportReceive::Message(message))) => assert_eq!(message.as_bytes(), &[0x10, 0x20, 0x30]),
        Ok(Ok(value)) => panic!("resumed receive returned unexpected result: {value:?}"),
        Ok(Err(error)) => panic!("resumed receive failed: {error}"),
        Err(_) => panic!("resumed receive timed out"),
    }
}

#[tokio::test(flavor = "current_thread")]
async fn truncated_frame_payload_is_a_protocol_failure() {
    let (server_session, client_session) = establish_private_sessions().await;
    let (mut raw_sender, _raw_receiver) = match client_session.inner.open_bi().await {
        Ok(value) => value,
        Err(error) => panic!("raw client stream open failed: {error}"),
    };
    let (server_sender, server_receiver) = match server_session.inner.accept_bi().await {
        Ok(value) => value,
        Err(error) => panic!("raw server stream accept failed: {error}"),
    };
    let server_connection = super::WebTransportConnection::new(server_session.inner, server_sender, server_receiver, server_session.transport);
    let (_server_sender, mut server_receiver) = game_realtime_transport_lib::RealtimeConnection::split(server_connection);
    if let Err(error) = raw_sender.write_all(&[0x00, 0x00, 0x00, 0x03, 0x10]).await {
        panic!("truncated frame payload write failed: {error}");
    }
    if let Err(error) = raw_sender.finish() {
        panic!("raw client stream finish failed: {error}");
    }
    let receive = tokio::time::timeout(TEST_TIMEOUT, game_realtime_transport_lib::RealtimeReceiver::receive(&mut server_receiver)).await;
    match receive {
        Ok(Ok(value)) => panic!("truncated frame payload produced a successful receive: {value:?}"),
        Ok(Err(error)) => assert_eq!(error.kind(), game_realtime_transport_lib::TransportErrorKind::Protocol),
        Err(_) => panic!("truncated frame payload was not rejected within the test timeout"),
    }
}

#[tokio::test(flavor = "current_thread")]
async fn truncated_frame_header_is_a_protocol_failure() {
    let (server_session, client_session) = establish_private_sessions().await;
    let (mut raw_sender, _raw_receiver) = match client_session.inner.open_bi().await {
        Ok(value) => value,
        Err(error) => panic!("raw client stream open failed: {error}"),
    };
    let (server_sender, server_receiver) = match server_session.inner.accept_bi().await {
        Ok(value) => value,
        Err(error) => panic!("raw server stream accept failed: {error}"),
    };
    let server_connection = super::WebTransportConnection::new(server_session.inner, server_sender, server_receiver, server_session.transport);
    let (_server_sender, mut server_receiver) = game_realtime_transport_lib::RealtimeConnection::split(server_connection);
    if let Err(error) = raw_sender.write_all(&[0x00, 0x00]).await {
        panic!("partial frame header write failed: {error}");
    }
    if let Err(error) = raw_sender.finish() {
        panic!("raw client stream finish failed: {error}");
    }
    let receive = tokio::time::timeout(TEST_TIMEOUT, game_realtime_transport_lib::RealtimeReceiver::receive(&mut server_receiver)).await;
    match receive {
        Ok(Ok(value)) => panic!("truncated frame header produced a successful receive: {value:?}"),
        Ok(Err(error)) => assert_eq!(error.kind(), game_realtime_transport_lib::TransportErrorKind::Protocol),
        Err(_) => panic!("truncated frame header was not rejected within the test timeout"),
    }
}

async fn establish_private_sessions() -> (super::WebTransportSession, super::WebTransportSession) {
    let identity = match super::WebTransportServerIdentity::generate_loopback() {
        Ok(value) => value,
        Err(error) => panic!("loopback identity generation failed: {error}"),
    };
    let certificate_hash = identity.certificate_hash().clone();
    let server_config = super::WebTransportServerConfig::new(std::net::SocketAddr::from(([127, 0, 0, 1], 0)), identity);
    let mut listener = match super::WebTransportListener::bind(server_config) {
        Ok(value) => value,
        Err(error) => panic!("WebTransport listener bind failed: {error}"),
    };
    let endpoint = format!("https://{}/private-test", listener.local_addr());
    let client_config = match super::WebTransportClientConfig::new(endpoint.as_str(), certificate_hash) {
        Ok(value) => value,
        Err(error) => panic!("WebTransport client configuration failed: {error}"),
    };
    let pair = tokio::time::timeout(TEST_TIMEOUT, async {
        return tokio::join!(listener.accept(), super::connect(&client_config));
    })
    .await;
    return match pair {
        Ok((Ok(server), Ok(client))) => (server, client),
        Ok((Err(error), _)) => panic!("WebTransport server establishment failed: {error}"),
        Ok((_, Err(error))) => panic!("WebTransport client establishment failed: {error}"),
        Err(_) => panic!("WebTransport private loopback establishment timed out"),
    };
}