// file: crates/ksp-onchain-transport-lib/unit_tests/ws_session.rs
// version: 2

use futures_util::SinkExt; // rust-rules: trait-import
use futures_util::StreamExt; // rust-rules: trait-import

fn local_endpoint(url: &str) -> crate::WsEndpointSettings {
    return local_endpoint_with_session(url, crate::WsSessionSettings::default());
}

fn local_endpoint_with_session(url: &str, session: crate::WsSessionSettings) -> crate::WsEndpointSettings {
    return crate::WsEndpointSettings::new(
        "local_ws",
        true,
        crate::WsProviderName::new("local-fixture"),
        crate::WsClusterName::new("local"),
        crate::WsProtocolKind::SolanaStandard,
        crate::WsEndpointUrl::parse(url).expect("local test WebSocket URL must parse"),
        session,
    );
}

fn session_settings(
    command_timeout: std::time::Duration,
    close_timeout: std::time::Duration,
    max_pending_requests: usize,
    max_message_size_bytes: usize,
    max_frame_size_bytes: usize,
    max_write_buffer_size_bytes: usize,
) -> crate::WsSessionSettings {
    let defaults = crate::WsSessionSettings::default();
    return crate::WsSessionSettings::new(
        command_timeout,
        close_timeout,
        defaults.reconnect().clone(),
        defaults.resubscribe(),
        defaults.command_queue_capacity(),
        defaults.notification_queue_capacity(),
        defaults.max_active_subscriptions(),
        max_pending_requests,
        max_message_size_bytes,
        max_frame_size_bytes,
        max_write_buffer_size_bytes,
    );
}

async fn bind_local_listener() -> (tokio::net::TcpListener, std::string::String) {
    let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.expect("local listener must bind");
    let address = listener.local_addr().expect("local listener must expose address");
    return (listener, format!("ws://{address}"));
}

async fn read_request(websocket: &mut tokio_tungstenite::WebSocketStream<tokio::net::TcpStream>) -> serde_json::Value {
    let message = websocket.next().await.expect("request message must exist").expect("request message must decode");
    let text = message.to_text().expect("request must be text");
    return serde_json::from_str(text).expect("request must contain JSON");
}

async fn send_result(websocket: &mut tokio_tungstenite::WebSocketStream<tokio::net::TcpStream>, request: &serde_json::Value, result: serde_json::Value) {
    let id = request.get("id").and_then(serde_json::Value::as_u64).expect("request id must be numeric");
    let response = serde_json::json!({"jsonrpc":"2.0","id":id,"result":result});
    websocket.send(tokio_tungstenite::tungstenite::Message::Text(response.to_string().into())).await.expect("local response must send");
}

async fn wait_for_state(session: &crate::WsSession, expected: crate::WsSessionState) {
    let deadline = tokio::time::Instant::now() + std::time::Duration::from_secs(1);
    loop {
        if session.state() == expected {
            return;
        }
        assert!(tokio::time::Instant::now() < deadline, "session did not reach expected state: {expected:?}");
        tokio::time::sleep(std::time::Duration::from_millis(5)).await;
    }
}

async fn wait_for_pending_count(session: &crate::WsSession, expected: usize) {
    let deadline = tokio::time::Instant::now() + std::time::Duration::from_secs(1);
    loop {
        if session.snapshot().pending_request_count() == expected {
            return;
        }
        assert!(tokio::time::Instant::now() < deadline, "session did not reach pending count {expected}");
        tokio::time::sleep(std::time::Duration::from_millis(5)).await;
    }
}

#[tokio::test(flavor = "current_thread")]
async fn websocket_session_connects_and_round_trips_internal_json_rpc() {
    let (listener, url) = bind_local_listener().await;
    let server = tokio::spawn(async move {
        let (stream, _) = listener.accept().await.expect("local server must accept client");
        let mut websocket = tokio_tungstenite::accept_async(stream).await.expect("local WebSocket handshake must succeed");
        let request = read_request(&mut websocket).await;
        assert_eq!(request.get("method").and_then(serde_json::Value::as_str), std::option::Option::Some("getVersion"));
        send_result(&mut websocket, &request, serde_json::json!({"solana-core":"fixture"})).await;
    });
    let session = crate::WsSession::connect(local_endpoint(url.as_str())).await.expect("client handshake must succeed");
    assert_eq!(session.state(), crate::WsSessionState::Active);
    assert_eq!(session.snapshot().pending_request_count(), 0);
    let result = session.execute_json_rpc("getVersion", std::vec::Vec::new()).await.expect("fixture JSON-RPC call must succeed");
    assert_eq!(result.get("solana-core").and_then(serde_json::Value::as_str), std::option::Option::Some("fixture"));
    tokio::task::yield_now().await;
    assert_eq!(session.snapshot().pending_request_count(), 0);
    server.await.expect("local server task must complete");
}

#[tokio::test(flavor = "current_thread")]
async fn websocket_sessions_are_physical_and_distinct_even_for_the_same_url() {
    let (listener, url) = bind_local_listener().await;
    let server = tokio::spawn(async move {
        let first = listener.accept().await.expect("first local client must connect");
        let first_ws = tokio_tungstenite::accept_async(first.0).await.expect("first handshake must succeed");
        let second = listener.accept().await.expect("second local client must connect");
        let second_ws = tokio_tungstenite::accept_async(second.0).await.expect("second handshake must succeed");
        return (first_ws, second_ws);
    });
    let first = crate::WsSession::connect(local_endpoint(url.as_str())).await.expect("first client must connect");
    let second = crate::WsSession::connect(local_endpoint(url.as_str())).await.expect("second client must connect");
    assert_ne!(first.id(), second.id());
    assert_eq!(first.snapshot().endpoint_name(), second.snapshot().endpoint_name());
    let _ = server.await.expect("local server task must complete");
}

#[tokio::test(flavor = "current_thread")]
async fn websocket_pending_map_dispatches_out_of_order_responses_by_request_id() {
    let (listener, url) = bind_local_listener().await;
    let server = tokio::spawn(async move {
        let (stream, _) = listener.accept().await.expect("local server must accept client");
        let mut websocket = tokio_tungstenite::accept_async(stream).await.expect("local WebSocket handshake must succeed");
        let first = read_request(&mut websocket).await;
        let second = read_request(&mut websocket).await;
        send_result(&mut websocket, &second, serde_json::json!("second")).await;
        send_result(&mut websocket, &first, serde_json::json!("first")).await;
    });
    let session = crate::WsSession::connect(local_endpoint(url.as_str())).await.expect("client handshake must succeed");
    let first_session = session.clone();
    let second_session = session.clone();
    let (first, second) = tokio::join!(
        first_session.execute_json_rpc("firstMethod", std::vec::Vec::new()),
        second_session.execute_json_rpc("secondMethod", std::vec::Vec::new())
    );
    assert_eq!(first.expect("first response must dispatch"), serde_json::json!("first"));
    assert_eq!(second.expect("second response must dispatch"), serde_json::json!("second"));
    tokio::task::yield_now().await;
    assert_eq!(session.snapshot().pending_request_count(), 0);
    server.await.expect("local server task must complete");
}

#[tokio::test(flavor = "current_thread")]
async fn websocket_rpc_application_error_does_not_fail_the_physical_session() {
    let (listener, url) = bind_local_listener().await;
    let server = tokio::spawn(async move {
        let (stream, _) = listener.accept().await.expect("local server must accept client");
        let mut websocket = tokio_tungstenite::accept_async(stream).await.expect("local WebSocket handshake must succeed");
        let request = read_request(&mut websocket).await;
        let id = request.get("id").and_then(serde_json::Value::as_u64).expect("request id must be numeric");
        let response = serde_json::json!({"jsonrpc":"2.0","id":id,"error":{"code":-32602,"message":"fixture invalid params"}});
        websocket.send(tokio_tungstenite::tungstenite::Message::Text(response.to_string().into())).await.expect("local error response must send");
        let request = read_request(&mut websocket).await;
        send_result(&mut websocket, &request, serde_json::json!(true)).await;
    });
    let session = crate::WsSession::connect(local_endpoint(url.as_str())).await.expect("client handshake must succeed");
    let error = session.execute_json_rpc("badMethod", std::vec::Vec::new()).await.expect_err("RPC application error must surface");
    assert_eq!(error.code(), crate::ERROR_CODE_RPC_APPLICATION_ERROR);
    assert_eq!(session.state(), crate::WsSessionState::Active);
    let result = session.execute_json_rpc("goodMethod", std::vec::Vec::new()).await.expect("session must remain usable");
    assert_eq!(result, serde_json::json!(true));
    server.await.expect("local server task must complete");
}

#[tokio::test(flavor = "current_thread")]
async fn websocket_connection_errors_do_not_echo_url_credentials() {
    let defaults = crate::WsSessionSettings::default();
    let short_session = crate::WsSessionSettings::new(
        std::time::Duration::from_millis(150),
        defaults.close_timeout(),
        defaults.reconnect().clone(),
        defaults.resubscribe(),
        defaults.command_queue_capacity(),
        defaults.notification_queue_capacity(),
        defaults.max_active_subscriptions(),
        defaults.max_pending_requests(),
        defaults.max_message_size_bytes(),
        defaults.max_frame_size_bytes(),
        defaults.max_write_buffer_size_bytes(),
    );
    let endpoint = crate::WsEndpointSettings::new(
        "redaction_fixture",
        true,
        crate::WsProviderName::new("fixture-provider"),
        crate::WsClusterName::new("local"),
        crate::WsProtocolKind::SolanaStandard,
        crate::WsEndpointUrl::parse("ws://user:password@127.0.0.1:1/private?api-key=SECRET-CANARY").expect("test URL must parse"),
        short_session,
    );
    let error = crate::WsSession::connect(endpoint).await.expect_err("unreachable local endpoint must fail");
    let rendered = format!("{error:?}");
    assert!(!rendered.contains("SECRET-CANARY"));
    assert!(!rendered.contains("password"));
    assert!(!rendered.contains("private?"));
}

#[tokio::test(flavor = "current_thread")]
async fn websocket_pending_request_capacity_rejects_only_the_excess_request() {
    let (listener, url) = bind_local_listener().await;
    let (first_seen_tx, first_seen_rx) = tokio::sync::oneshot::channel();
    let (release_tx, release_rx) = tokio::sync::oneshot::channel();
    let server = tokio::spawn(async move {
        let (stream, _) = listener.accept().await.expect("local server must accept client");
        let mut websocket = tokio_tungstenite::accept_async(stream).await.expect("local WebSocket handshake must succeed");
        let first = read_request(&mut websocket).await;
        let _ = first_seen_tx.send(());
        let _ = release_rx.await;
        send_result(&mut websocket, &first, serde_json::json!("first")).await;
    });
    let settings = session_settings(std::time::Duration::from_secs(1), std::time::Duration::from_millis(200), 1, 64 * 1024, 64 * 1024, 64 * 1024);
    let session = crate::WsSession::connect(local_endpoint_with_session(url.as_str(), settings)).await.expect("client handshake must succeed");
    let first_session = session.clone();
    let first = tokio::spawn(async move {
        return first_session.execute_json_rpc("firstMethod", std::vec::Vec::new()).await;
    });
    first_seen_rx.await.expect("server must observe first request");
    wait_for_pending_count(&session, 1).await;
    let second_error = session.execute_json_rpc("secondMethod", std::vec::Vec::new()).await.expect_err("second pending request must be rejected");
    assert_eq!(second_error.code(), crate::ERROR_CODE_WS_BACKPRESSURE_OVERFLOW);
    assert_eq!(session.state(), crate::WsSessionState::Active);
    release_tx.send(()).expect("first request release signal must send");
    assert_eq!(first.await.expect("first request task must join").expect("first request must complete"), serde_json::json!("first"));
    wait_for_pending_count(&session, 0).await;
    server.await.expect("local server task must complete");
}

#[tokio::test(flavor = "current_thread")]
async fn websocket_oversized_outbound_request_is_rejected_before_socket_write() {
    let (listener, url) = bind_local_listener().await;
    let server = tokio::spawn(async move {
        let (stream, _) = listener.accept().await.expect("local server must accept client");
        let mut websocket = tokio_tungstenite::accept_async(stream).await.expect("local WebSocket handshake must succeed");
        let request = read_request(&mut websocket).await;
        assert_eq!(request.get("method").and_then(serde_json::Value::as_str), std::option::Option::Some("smallMethod"));
        send_result(&mut websocket, &request, serde_json::json!(true)).await;
    });
    let settings = session_settings(std::time::Duration::from_secs(1), std::time::Duration::from_millis(200), 8, 256, 128, 1024);
    let session = crate::WsSession::connect(local_endpoint_with_session(url.as_str(), settings)).await.expect("client handshake must succeed");
    let oversized = serde_json::json!({"value":"X".repeat(512)});
    let error = session.execute_json_rpc("oversizedMethod", std::vec![oversized]).await.expect_err("oversized outbound request must be rejected");
    assert_eq!(error.code(), crate::ERROR_CODE_INVALID_RPC_PARAMETERS);
    assert_eq!(session.state(), crate::WsSessionState::Active);
    let result = session.execute_json_rpc("smallMethod", std::vec::Vec::new()).await.expect("small request must still succeed");
    assert_eq!(result, serde_json::json!(true));
    server.await.expect("local server task must complete");
}

#[tokio::test(flavor = "current_thread")]
async fn websocket_oversized_inbound_frame_fails_before_json_decode() {
    let (listener, url) = bind_local_listener().await;
    let server = tokio::spawn(async move {
        let (stream, _) = listener.accept().await.expect("local server must accept client");
        let mut websocket = tokio_tungstenite::accept_async(stream).await.expect("local WebSocket handshake must succeed");
        websocket.send(tokio_tungstenite::tungstenite::Message::Text("X".repeat(512).into())).await.expect("oversized fixture message must send");
        tokio::time::sleep(std::time::Duration::from_millis(200)).await;
    });
    let settings = session_settings(std::time::Duration::from_secs(1), std::time::Duration::from_millis(200), 8, 128, 64, 1024);
    let session = crate::WsSession::connect(local_endpoint_with_session(url.as_str(), settings)).await.expect("client handshake must succeed");
    wait_for_state(&session, crate::WsSessionState::Failed).await;
    server.await.expect("local server task must complete");
}

#[tokio::test(flavor = "current_thread")]
async fn websocket_pending_request_timeout_purges_capacity_without_failing_session() {
    let (listener, url) = bind_local_listener().await;
    let server = tokio::spawn(async move {
        let (stream, _) = listener.accept().await.expect("local server must accept client");
        let mut websocket = tokio_tungstenite::accept_async(stream).await.expect("local WebSocket handshake must succeed");
        let _ = read_request(&mut websocket).await;
        tokio::time::sleep(std::time::Duration::from_millis(400)).await;
    });
    let settings = session_settings(std::time::Duration::from_millis(100), std::time::Duration::from_millis(100), 1, 64 * 1024, 64 * 1024, 64 * 1024);
    let session = crate::WsSession::connect(local_endpoint_with_session(url.as_str(), settings)).await.expect("client handshake must succeed");
    let wait = tokio::time::timeout(std::time::Duration::from_secs(1), session.execute_json_rpc("timeoutMethod", std::vec::Vec::new())).await;
    let error = wait.expect("request timeout fixture must remain bounded").expect_err("remote silence must time out the request");
    assert_eq!(error.code(), crate::ERROR_CODE_TIMEOUT);
    wait_for_pending_count(&session, 0).await;
    assert_eq!(session.state(), crate::WsSessionState::Active);
    server.await.expect("local server task must complete");
}

#[tokio::test(flavor = "current_thread")]
async fn websocket_ping_flushes_automatic_pong_and_keeps_session_active() {
    let (listener, url) = bind_local_listener().await;
    let (pong_tx, pong_rx) = tokio::sync::oneshot::channel();
    let server = tokio::spawn(async move {
        let (stream, _) = listener.accept().await.expect("local server must accept client");
        let mut websocket = tokio_tungstenite::accept_async(stream).await.expect("local WebSocket handshake must succeed");
        websocket.send(tokio_tungstenite::tungstenite::Message::Ping(b"ping-canary".to_vec().into())).await.expect("fixture ping must send");
        let pong = websocket.next().await.expect("pong frame must arrive").expect("pong frame must decode");
        match pong {
            tokio_tungstenite::tungstenite::Message::Pong(payload) => assert_eq!(payload.as_ref(), b"ping-canary"),
            other => panic!("expected Pong frame, got {other:?}"),
        }
        let _ = pong_tx.send(());
        let request = read_request(&mut websocket).await;
        send_result(&mut websocket, &request, serde_json::json!(true)).await;
    });
    let session = crate::WsSession::connect(local_endpoint(url.as_str())).await.expect("client handshake must succeed");
    tokio::time::timeout(std::time::Duration::from_secs(1), pong_rx)
        .await
        .expect("automatic Pong must remain bounded")
        .expect("fixture server must observe Pong");
    assert_eq!(session.state(), crate::WsSessionState::Active);
    let result = session.execute_json_rpc("afterPing", std::vec::Vec::new()).await.expect("session must remain usable after Ping/Pong");
    assert_eq!(result, serde_json::json!(true));
    server.await.expect("local server task must complete");
}

#[tokio::test(flavor = "current_thread")]
async fn websocket_remote_close_transitions_to_closed_instead_of_failed() {
    let (listener, url) = bind_local_listener().await;
    let server = tokio::spawn(async move {
        let (stream, _) = listener.accept().await.expect("local server must accept client");
        let mut websocket = tokio_tungstenite::accept_async(stream).await.expect("local WebSocket handshake must succeed");
        websocket.send(tokio_tungstenite::tungstenite::Message::Close(std::option::Option::None)).await.expect("fixture Close must send");
        let _ = tokio::time::timeout(std::time::Duration::from_millis(200), websocket.next()).await;
    });
    let session = crate::WsSession::connect(local_endpoint(url.as_str())).await.expect("client handshake must succeed");
    wait_for_state(&session, crate::WsSessionState::Closed).await;
    assert!(session.close().await.is_ok());
    server.await.expect("local server task must complete");
}

#[tokio::test(flavor = "current_thread")]
async fn websocket_explicit_close_cancels_pending_and_finishes_with_hostile_peer() {
    let (listener, url) = bind_local_listener().await;
    let (request_seen_tx, request_seen_rx) = tokio::sync::oneshot::channel();
    let server = tokio::spawn(async move {
        let (stream, _) = listener.accept().await.expect("local server must accept client");
        let mut websocket = tokio_tungstenite::accept_async(stream).await.expect("local WebSocket handshake must succeed");
        let _ = read_request(&mut websocket).await;
        let _ = request_seen_tx.send(());
        tokio::time::sleep(std::time::Duration::from_millis(500)).await;
    });
    let settings = session_settings(std::time::Duration::from_secs(1), std::time::Duration::from_millis(150), 8, 64 * 1024, 64 * 1024, 64 * 1024);
    let session = crate::WsSession::connect(local_endpoint_with_session(url.as_str(), settings)).await.expect("client handshake must succeed");
    let request_session = session.clone();
    let pending = tokio::spawn(async move {
        return request_session.execute_json_rpc("neverRespond", std::vec::Vec::new()).await;
    });
    request_seen_rx.await.expect("hostile server must observe request");
    wait_for_pending_count(&session, 1).await;
    let close_result = tokio::time::timeout(std::time::Duration::from_millis(300), session.close()).await;
    close_result.expect("explicit close must remain bounded").expect("explicit close must finish cleanly");
    assert_eq!(session.state(), crate::WsSessionState::Closed);
    assert_eq!(session.snapshot().pending_request_count(), 0);
    let pending_error = pending.await.expect("pending request task must join").expect_err("shutdown must cancel pending request");
    assert_eq!(pending_error.code(), crate::ERROR_CODE_WS_SESSION_CLOSED);
    server.await.expect("hostile server task must complete");
}

#[tokio::test(flavor = "current_thread")]
async fn websocket_repeated_connect_close_cycles_are_bounded() {
    const CYCLES: usize = 8;
    let (listener, url) = bind_local_listener().await;
    let server = tokio::spawn(async move {
        for _ in 0..CYCLES {
            let (stream, _) = listener.accept().await.expect("local server must accept client");
            let mut websocket = tokio_tungstenite::accept_async(stream).await.expect("local WebSocket handshake must succeed");
            let message = websocket.next().await.expect("client Close must arrive").expect("client Close must decode");
            assert!(matches!(message, tokio_tungstenite::tungstenite::Message::Close(_)));
            let _ = websocket.flush().await;
        }
    });
    let settings = session_settings(std::time::Duration::from_secs(1), std::time::Duration::from_millis(200), 8, 64 * 1024, 64 * 1024, 64 * 1024);
    for _ in 0..CYCLES {
        let session = crate::WsSession::connect(local_endpoint_with_session(url.as_str(), settings.clone())).await.expect("client must connect");
        session.close().await.expect("client close must succeed");
        assert_eq!(session.state(), crate::WsSessionState::Closed);
    }
    tokio::time::timeout(std::time::Duration::from_secs(2), server)
        .await
        .expect("repeated close server must remain bounded")
        .expect("repeated close server task must join");
}