use std::collections::HashMap;

use http::{Method, StatusCode};
use oagw::test_support::{
    APIKEY_AUTH_PLUGIN_ID, AppHarness, MockBody, MockGuard, MockResponse, MockUpstream,
    OAUTH2_CLIENT_CRED_AUTH_PLUGIN_ID,
};
use oagw_sdk::Body;
use oagw_sdk::api::ErrorSource;
use oagw_sdk::{
    BurstConfig, CorsConfig, CorsHttpMethod, CreateRouteRequest, CreateUpstreamRequest, Endpoint,
    HeadersConfig, HttpMatch, HttpMethod, MatchRules, PassthroughMode, PathSuffixMode,
    PluginBinding, PluginsConfig, RateLimitAlgorithm, RateLimitConfig, RateLimitScope,
    RateLimitStrategy, RequestHeaderRules, ResponseHeaderRules, Scheme, Server, SharingMode,
    SustainedRate, Window,
};
use serde_json::json;

async fn setup_openai_mock() -> AppHarness {
    let h = AppHarness::builder()
        .with_credentials(vec![("cred://openai-key".into(), "sk-test123".into())])
        .build()
        .await;

    let resp = h
        .api_v1()
        .post_upstream()
        .with_body(serde_json::json!({
            "server": {
                "endpoints": [{"host": "127.0.0.1", "port": h.mock_port(), "scheme": "http"}]
            },
            "protocol": "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            "alias": "mock-upstream",
            "enabled": true,
            "tags": [],
            "auth": {
                "type": APIKEY_AUTH_PLUGIN_ID,
                "sharing": "private",
                "config": {
                    "header": "authorization",
                    "prefix": "Bearer ",
                    "secret_ref": "cred://openai-key"
                }
            }
        }))
        .expect_status(201)
        .await;
    let upstream_id = resp.json()["id"].as_str().unwrap().to_string();

    for (methods, path) in [
        (vec!["POST", "GET"], "/v1/chat/completions"),
        (vec!["GET"], "/error"),
    ] {
        h.api_v1()
            .post_route()
            .with_body(serde_json::json!({
                "upstream_id": &upstream_id,
                "match": {
                    "http": {
                        "methods": methods,
                        "path": path
                    }
                },
                "enabled": true,
                "tags": [],
                "priority": 0
            }))
            .expect_status(201)
            .await;
    }

    h
}

// 6.13: Full pipeline — proxy POST /v1/chat/completions with JSON body.
#[tokio::test]
async fn proxy_chat_completion_round_trip() {
    let h = setup_openai_mock().await;

    let req = http::Request::builder()
        .method(Method::POST)
        .uri("/mock-upstream/v1/chat/completions")
        .header(http::header::CONTENT_TYPE, "application/json")
        .body(Body::from(
            r#"{"model":"gpt-4","messages":[{"role":"user","content":"Hello"}]}"#,
        ))
        .unwrap();
    let response = h
        .facade()
        .proxy_request(h.security_context().clone(), req)
        .await
        .unwrap();

    assert_eq!(response.status(), StatusCode::OK);

    let body_bytes = response.into_body().into_bytes().await.unwrap();
    let body_json: serde_json::Value = serde_json::from_slice(&body_bytes).unwrap();
    assert!(body_json.get("id").is_some());
    assert!(body_json.get("choices").is_some());
}

// 6.13 (auth): Verify the mock received the Authorization header.
#[tokio::test]
async fn proxy_injects_auth_header() {
    let mut guard = MockGuard::new();
    guard.mock(
        "POST",
        "/v1/chat/completions",
        MockResponse {
            status: 200,
            headers: vec![("content-type".into(), "application/json".into())],
            body: MockBody::Json(json!({
                "id": "chatcmpl-auth-test",
                "object": "chat.completion",
                "choices": [{"index": 0, "message": {"role": "assistant", "content": "ok"}, "finish_reason": "stop"}]
            })),
        },
    );

    let h = AppHarness::builder()
        .with_credentials(vec![("cred://openai-key".into(), "sk-test123".into())])
        .build()
        .await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("auth-hdr-test")
            .auth(oagw_sdk::AuthConfig {
                plugin_type: APIKEY_AUTH_PLUGIN_ID.into(),
                sharing: SharingMode::Private,
                config: Some(
                    [
                        ("header".into(), "authorization".into()),
                        ("prefix".into(), "Bearer ".into()),
                        ("secret_ref".into(), "cred://openai-key".into()),
                    ]
                    .into_iter()
                    .collect(),
                ),
            })
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Post],
                        path: guard.path("/v1/chat/completions"),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Disabled,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    let req = http::Request::builder()
        .method(Method::POST)
        .uri(format!(
            "/auth-hdr-test{}",
            guard.path("/v1/chat/completions")
        ))
        .header(http::header::CONTENT_TYPE, "application/json")
        .body(Body::from(
            r#"{"model":"gpt-4","messages":[{"role":"user","content":"Hello"}]}"#,
        ))
        .unwrap();
    let response = h.facade().proxy_request(ctx, req).await.unwrap();
    assert_eq!(response.status(), StatusCode::OK);

    let recorded = guard.recorded_requests().await;
    assert_eq!(recorded.len(), 1);
    let auth_header = recorded[0]
        .headers
        .iter()
        .find(|(k, _)| k == "authorization")
        .map(|(_, v)| v.as_str())
        .expect("authorization header missing");
    assert_eq!(auth_header, "Bearer sk-test123");
}

// 6.14: SSE streaming — proxy to dynamic SSE mock via MockGuard.
#[tokio::test]
async fn proxy_sse_streaming() {
    let mut guard = MockGuard::new();

    let chunks: Vec<String> = vec![
        json!({"id":"chatcmpl-mock-stream","object":"chat.completion.chunk","choices":[{"index":0,"delta":{"role":"assistant","content":"Hello"},"finish_reason":null}]}).to_string(),
        json!({"id":"chatcmpl-mock-stream","object":"chat.completion.chunk","choices":[{"index":0,"delta":{},"finish_reason":"stop"}]}).to_string(),
        "[DONE]".to_string(),
    ];
    guard.mock(
        "POST",
        "/v1/chat/completions/stream",
        MockResponse {
            status: 200,
            headers: vec![("content-type".into(), "text/event-stream".into())],
            body: MockBody::Sse(chunks),
        },
    );

    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("sse-test")
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Post],
                        path: guard.path("/v1/chat/completions/stream"),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Disabled,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    let req = http::Request::builder()
        .method(Method::POST)
        .uri(format!(
            "/sse-test{}",
            guard.path("/v1/chat/completions/stream")
        ))
        .header(http::header::CONTENT_TYPE, "application/json")
        .body(Body::from(r#"{"model":"gpt-4","stream":true}"#))
        .unwrap();
    let response = h.facade().proxy_request(ctx, req).await.unwrap();

    let ct = response
        .headers()
        .get("content-type")
        .unwrap()
        .to_str()
        .unwrap();
    assert!(ct.contains("text/event-stream"), "got content-type: {ct}");

    let body_bytes = response.into_body().into_bytes().await.unwrap();
    let body_str = String::from_utf8(body_bytes.to_vec()).unwrap();
    assert!(body_str.contains("data: [DONE]"));
}

// 6.15: Upstream 500 error passthrough.
#[tokio::test]
async fn proxy_upstream_500_passthrough() {
    let h = setup_openai_mock().await;

    let req = http::Request::builder()
        .method(Method::GET)
        .uri("/mock-upstream/error/500")
        .body(Body::Empty)
        .unwrap();
    let response = h
        .facade()
        .proxy_request(h.security_context().clone(), req)
        .await
        .unwrap();

    assert_eq!(response.status(), StatusCode::INTERNAL_SERVER_ERROR);
    assert_eq!(
        response.extensions().get::<ErrorSource>().copied(),
        Some(ErrorSource::Upstream)
    );
}

// 6.17: Pipeline abort — nonexistent alias returns 404 without calling mock.
#[tokio::test]
async fn proxy_nonexistent_alias_returns_404() {
    let h = setup_openai_mock().await;

    let req = http::Request::builder()
        .method(Method::GET)
        .uri("/nonexistent/v1/test")
        .body(Body::Empty)
        .unwrap();
    match h
        .facade()
        .proxy_request(h.security_context().clone(), req)
        .await
    {
        Err(err) => assert!(matches!(
            err,
            oagw_sdk::error::ServiceGatewayError::NotFound { .. }
        )),
        Ok(_) => panic!("expected error"),
    }
}

// 6.17: Pipeline abort — disabled upstream returns 503.
#[tokio::test]
async fn proxy_disabled_upstream_returns_503() {
    let h = setup_openai_mock().await;
    let ctx = h.security_context().clone();

    let _upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: 9999,
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("disabled-upstream")
            .enabled(false)
            .build(),
        )
        .await
        .unwrap();

    let req = http::Request::builder()
        .method(Method::GET)
        .uri("/disabled-upstream/test")
        .body(Body::Empty)
        .unwrap();
    match h.facade().proxy_request(ctx.clone(), req).await {
        Err(err) => assert!(matches!(
            err,
            oagw_sdk::error::ServiceGatewayError::UpstreamDisabled { .. }
        )),
        Ok(_) => panic!("expected error"),
    }
}

// 6.17: Pipeline abort — rate limit exceeded returns 429.
#[tokio::test]
async fn proxy_rate_limit_exceeded_returns_429() {
    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("rate-limited")
            .rate_limit(RateLimitConfig {
                sharing: SharingMode::Private,
                algorithm: RateLimitAlgorithm::TokenBucket,
                sustained: SustainedRate {
                    rate: 1,
                    window: Window::Minute,
                },
                burst: Some(BurstConfig { capacity: 1 }),
                scope: RateLimitScope::Tenant,
                strategy: RateLimitStrategy::Reject,
                cost: 1,
            })
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Get],
                        path: "/v1/models".into(),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Append,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    // First request should succeed.
    let req = http::Request::builder()
        .method(Method::GET)
        .uri("/rate-limited/v1/models")
        .body(Body::Empty)
        .unwrap();
    let response = h.facade().proxy_request(ctx.clone(), req).await.unwrap();
    assert_eq!(response.status(), StatusCode::OK);

    // Second request should be rate limited.
    let req = http::Request::builder()
        .method(Method::GET)
        .uri("/rate-limited/v1/models")
        .body(Body::Empty)
        .unwrap();
    match h.facade().proxy_request(ctx.clone(), req).await {
        Err(err) => assert!(matches!(
            err,
            oagw_sdk::error::ServiceGatewayError::RateLimitExceeded { .. }
        )),
        Ok(_) => panic!("expected rate limit error"),
    }
}

// 6.16: Upstream timeout — proxy to gated mock that never responds, assert 504.
// Uses multi_thread runtime so the timer driver runs on a dedicated thread,
// preventing stalls when other test binaries compete for CPU.
#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
async fn proxy_upstream_timeout_returns_504() {
    let mut guard = MockGuard::new();
    // Register a gated route that will never respond (sender kept alive but not signaled).
    let _gate = guard.mock_gated(
        "GET",
        "/timeout",
        MockResponse {
            status: 200,
            headers: vec![],
            body: MockBody::Json(json!({"ok": true})),
        },
    );

    let h = AppHarness::builder()
        .with_request_timeout(std::time::Duration::from_millis(500))
        .build()
        .await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("timeout-upstream")
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Get],
                        path: guard.path("/timeout"),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Disabled,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    let req = http::Request::builder()
        .method(Method::GET)
        .uri(format!("/timeout-upstream{}", guard.path("/timeout")))
        .body(Body::Empty)
        .unwrap();
    match h.facade().proxy_request(ctx.clone(), req).await {
        Err(err) => assert!(matches!(
            err,
            oagw_sdk::error::ServiceGatewayError::RequestTimeout { .. }
        )),
        Ok(_) => panic!("expected timeout error"),
    }
}

// 8.9: Query allowlist enforcement.
#[tokio::test]
async fn proxy_query_allowlist_allowed_param_succeeds() {
    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("ql-test")
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Get],
                        path: "/v1/models".into(),
                        query_allowlist: vec!["version".into()],
                        path_suffix_mode: PathSuffixMode::Append,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    let req = http::Request::builder()
        .method(Method::GET)
        .uri("/ql-test/v1/models?version=2")
        .body(Body::Empty)
        .unwrap();
    let response = h.facade().proxy_request(ctx.clone(), req).await.unwrap();
    assert_eq!(response.status(), StatusCode::OK);
}

#[tokio::test]
async fn proxy_query_allowlist_unknown_param_rejected() {
    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("ql-reject")
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Get],
                        path: "/v1/models".into(),
                        query_allowlist: vec!["version".into()],
                        path_suffix_mode: PathSuffixMode::Append,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    let req = http::Request::builder()
        .method(Method::GET)
        .uri("/ql-reject/v1/models?version=2&debug=true")
        .body(Body::Empty)
        .unwrap();
    match h.facade().proxy_request(ctx.clone(), req).await {
        Err(err) => assert!(matches!(
            err,
            oagw_sdk::error::ServiceGatewayError::ValidationError { .. }
        )),
        Ok(_) => panic!("expected validation error"),
    }
}

// 13.5: Non-existent auth plugin ID returns error through proxy pipeline.
#[tokio::test]
async fn proxy_nonexistent_auth_plugin_returns_error() {
    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("bad-auth")
            .auth(oagw_sdk::AuthConfig {
                plugin_type: "gts.x.core.oagw.auth.v1~nonexistent.plugin.v1".into(),
                sharing: SharingMode::Private,
                config: None,
            })
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Get],
                        path: "/v1/test".into(),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Append,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    let req = http::Request::builder()
        .method(Method::GET)
        .uri("/bad-auth/v1/test")
        .body(Body::Empty)
        .unwrap();
    match h.facade().proxy_request(ctx.clone(), req).await {
        Err(err) => assert!(matches!(
            err,
            oagw_sdk::error::ServiceGatewayError::AuthenticationFailed { .. }
        )),
        Ok(_) => panic!("expected authentication error for non-existent plugin"),
    }
}

// 13.6: Assert on recorded_requests() URI and body content.
#[tokio::test]
async fn proxy_recorded_request_has_correct_uri_and_body() {
    let mut guard = MockGuard::new();
    guard.mock(
        "POST",
        "/v1/chat/completions",
        MockResponse {
            status: 200,
            headers: vec![("content-type".into(), "application/json".into())],
            body: MockBody::Json(json!({
                "id": "chatcmpl-rec-test",
                "object": "chat.completion",
                "choices": [{"index": 0, "message": {"role": "assistant", "content": "ok"}, "finish_reason": "stop"}]
            })),
        },
    );

    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("rec-test")
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Post],
                        path: guard.path("/v1/chat/completions"),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Disabled,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    let body_payload = r#"{"model":"gpt-4","messages":[{"role":"user","content":"Hello"}]}"#;
    let req = http::Request::builder()
        .method(Method::POST)
        .uri(format!("/rec-test{}", guard.path("/v1/chat/completions")))
        .header(http::header::CONTENT_TYPE, "application/json")
        .body(Body::from(body_payload))
        .unwrap();
    let response = h.facade().proxy_request(ctx, req).await.unwrap();
    assert_eq!(response.status(), StatusCode::OK);

    let recorded = guard.recorded_requests().await;
    assert_eq!(recorded.len(), 1);
    assert!(recorded[0].uri.ends_with("/v1/chat/completions"));
    assert_eq!(recorded[0].method, "POST");

    let body_str = String::from_utf8(recorded[0].body.clone()).unwrap();
    assert!(body_str.contains("gpt-4"));
    assert!(body_str.contains("Hello"));
}

// Response header sanitization: hop-by-hop and x-oagw-* headers stripped from upstream response.
#[tokio::test]
async fn proxy_response_headers_sanitized() {
    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("resp-hdr-test")
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Get],
                        path: "/response-headers".into(),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Append,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    let req = http::Request::builder()
        .method(Method::GET)
        .uri("/resp-hdr-test/response-headers")
        .body(Body::Empty)
        .unwrap();
    let response = h.facade().proxy_request(ctx.clone(), req).await.unwrap();
    assert_eq!(response.status(), StatusCode::OK);

    let resp_headers = response.headers();

    // Safe headers should be preserved.
    assert_eq!(
        resp_headers.get("x-custom-safe").unwrap(),
        "keep-me",
        "safe custom header should be forwarded"
    );
    assert!(
        resp_headers.get("content-type").is_some(),
        "content-type should be preserved"
    );

    // Hop-by-hop headers should be stripped.
    assert!(
        resp_headers.get("proxy-authenticate").is_none(),
        "proxy-authenticate should be stripped from response"
    );
    assert!(
        resp_headers.get("trailer").is_none(),
        "trailer should be stripped from response"
    );
    assert!(
        resp_headers.get("upgrade").is_none(),
        "upgrade should be stripped from response"
    );

    // Internal x-oagw-* headers should be stripped.
    assert!(
        resp_headers.get("x-oagw-debug").is_none(),
        "x-oagw-debug should be stripped from response"
    );
    assert!(
        resp_headers.get("x-oagw-trace-id").is_none(),
        "x-oagw-trace-id should be stripped from response"
    );
}

// 8.10: path_suffix_mode=disabled rejects suffix; append succeeds.
#[tokio::test]
async fn proxy_path_suffix_disabled_rejects_extra_path() {
    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("psm-test")
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Get],
                        path: "/v1/models".into(),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Disabled,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    // Exact path succeeds.
    let req = http::Request::builder()
        .method(Method::GET)
        .uri("/psm-test/v1/models")
        .body(Body::Empty)
        .unwrap();
    let response = h.facade().proxy_request(ctx.clone(), req).await.unwrap();
    assert_eq!(response.status(), StatusCode::OK);

    // Extra suffix rejected with 400.
    let req = http::Request::builder()
        .method(Method::GET)
        .uri("/psm-test/v1/models/gpt-4")
        .body(Body::Empty)
        .unwrap();
    match h.facade().proxy_request(ctx.clone(), req).await {
        Err(err) => assert!(matches!(
            err,
            oagw_sdk::error::ServiceGatewayError::ValidationError { .. }
        )),
        Ok(_) => panic!("expected validation error for disabled path_suffix_mode"),
    }
}

// ---------------------------------------------------------------------------
// Multi-endpoint load balancing integration tests
// ---------------------------------------------------------------------------

// positive-2.1 (custom-header-routing), positive-2.10 (upstreams): Round-robin distribution across 2 endpoints.
//
// Uses a single mock on 127.0.0.1 with two identical endpoint entries so the
// test works on all platforms (macOS only has 127.0.0.1 on loopback by default).
// Actual round-robin distribution across distinct backends is covered by unit
// tests in pingora_proxy.rs (`select_round_robin_distribution`) and service.rs
// (`select_endpoint_round_robin_fallback`).  This integration test verifies the
// full proxy pipeline succeeds with a multi-endpoint upstream configuration.
#[tokio::test]
async fn proxy_multi_endpoint_round_robin() {
    let mock = MockUpstream::start().await;
    let port = mock.addr().port();

    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![
                        Endpoint {
                            scheme: Scheme::Http,
                            host: "127.0.0.1".into(),
                            port,
                        },
                        Endpoint {
                            scheme: Scheme::Http,
                            host: "127.0.0.1".into(),
                            port,
                        },
                    ],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("rr-test")
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Get],
                        path: "/v1/models".into(),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Append,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    // Send 4 requests — all reach the single mock via the multi-endpoint pool.
    for _ in 0..4 {
        let req = http::Request::builder()
            .method(Method::GET)
            .uri("/rr-test/v1/models")
            .body(Body::Empty)
            .unwrap();
        let response = h.facade().proxy_request(ctx.clone(), req).await.unwrap();
        assert_eq!(response.status(), StatusCode::OK);
    }

    assert_eq!(
        mock.recorded_requests().await.len(),
        4,
        "mock should have received all 4 requests"
    );
}

// positive-2.2 (custom-header-routing): X-OAGW-Target-Host explicit selection.
//
// Uses a single mock on 127.0.0.1 with two identical endpoint entries so the
// test works on all platforms (macOS only has 127.0.0.1 on loopback by default).
// This test verifies the header is accepted without error; actual host-based
// routing is covered by the unit test `select_endpoint_target_host_matches` in
// service.rs.
#[tokio::test]
async fn proxy_target_host_header_selects_endpoint() {
    let mock = MockUpstream::start().await;
    let port = mock.addr().port();

    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![
                        Endpoint {
                            scheme: Scheme::Http,
                            host: "127.0.0.1".into(),
                            port,
                        },
                        Endpoint {
                            scheme: Scheme::Http,
                            host: "127.0.0.1".into(),
                            port,
                        },
                    ],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("target-host-test")
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Get],
                        path: "/v1/models".into(),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Append,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    // Send request with X-OAGW-Target-Host header selecting endpoint host.
    let req = http::Request::builder()
        .method(Method::GET)
        .uri("/target-host-test/v1/models")
        .header("x-oagw-target-host", "127.0.0.1")
        .body(Body::Empty)
        .unwrap();
    let response = h.facade().proxy_request(ctx.clone(), req).await.unwrap();
    assert_eq!(response.status(), StatusCode::OK);
}

// negative-2.1 (custom-header-routing): X-OAGW-Target-Host validation — unknown host returns error.
#[tokio::test]
async fn proxy_target_host_unknown_returns_error() {
    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("target-host-unknown")
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Get],
                        path: "/v1/models".into(),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Append,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    let req = http::Request::builder()
        .method(Method::GET)
        .uri("/target-host-unknown/v1/models")
        .header("x-oagw-target-host", "unknown.com")
        .body(Body::Empty)
        .unwrap();

    match h.facade().proxy_request(ctx.clone(), req).await {
        Err(err) => assert!(
            matches!(
                err,
                oagw_sdk::error::ServiceGatewayError::UnknownTargetHost { .. }
            ),
            "expected UnknownTargetHost, got: {err:?}"
        ),
        Ok(_) => panic!("expected error for unknown target host"),
    }
}

// negative-2.10 (upstreams): All backends unreachable returns connection error (502).
#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
async fn proxy_all_backends_unreachable() {
    let h = AppHarness::builder()
        .with_request_timeout(std::time::Duration::from_secs(5))
        .build()
        .await;
    let ctx = h.security_context().clone();

    // Ports 19991/19992 are unlikely to be listening.
    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: 19991,
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("unreachable-test")
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Get],
                        path: "/v1/models".into(),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Append,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    let req = http::Request::builder()
        .method(Method::GET)
        .uri("/unreachable-test/v1/models")
        .body(Body::Empty)
        .unwrap();

    match h.facade().proxy_request(ctx.clone(), req).await {
        Err(err) => assert!(
            matches!(
                err,
                oagw_sdk::error::ServiceGatewayError::DownstreamError { .. }
            ),
            "expected DownstreamError for unreachable backend, got: {err:?}"
        ),
        Ok(resp) => {
            // Pingora may return a 502 response directly via fail_to_proxy.
            assert!(
                resp.status() == StatusCode::BAD_GATEWAY
                    || resp.status() == StatusCode::GATEWAY_TIMEOUT,
                "expected 502 or 504, got: {}",
                resp.status()
            );
        }
    }
}

// positive-2.13 (upstreams): CRUD invalidation — update upstream endpoints, verify new endpoint used.
#[tokio::test]
async fn proxy_crud_invalidation_after_update() {
    let mock_a = MockUpstream::start().await;
    let mock_b = MockUpstream::start().await;
    let port_a = mock_a.addr().port();
    let port_b = mock_b.addr().port();

    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    // Create upstream pointing to mock_a only.
    let resp = h
        .api_v1()
        .post_upstream()
        .with_body(json!({
            "server": {
                "endpoints": [{"host": "127.0.0.1", "port": port_a, "scheme": "http"}]
            },
            "protocol": "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            "alias": "crud-invalidation",
            "enabled": true,
            "tags": []
        }))
        .expect_status(201)
        .await;
    let upstream_id = resp.json()["id"].as_str().unwrap().to_string();

    h.api_v1()
        .post_route()
        .with_body(json!({
            "upstream_id": &upstream_id,
            "match": {
                "http": {
                    "methods": ["GET"],
                    "path": "/v1/models"
                }
            },
            "enabled": true,
            "tags": [],
            "priority": 0
        }))
        .expect_status(201)
        .await;

    // Proxy to mock_a.
    let req = http::Request::builder()
        .method(Method::GET)
        .uri("/crud-invalidation/v1/models")
        .body(Body::Empty)
        .unwrap();
    let response = h.facade().proxy_request(ctx.clone(), req).await.unwrap();
    assert_eq!(response.status(), StatusCode::OK);
    assert_eq!(
        mock_a.recorded_requests().await.len(),
        1,
        "mock_a should have received 1 request"
    );
    assert_eq!(
        mock_b.recorded_requests().await.len(),
        0,
        "mock_b should have received 0 requests"
    );

    // Update upstream to point to mock_b via REST API (triggers invalidation).
    h.api_v1()
        .put_upstream(&upstream_id)
        .with_body(json!({
            "server": {
                "endpoints": [{"host": "127.0.0.1", "port": port_b, "scheme": "http"}]
            },
            "protocol": "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            "alias": "crud-invalidation",
            "enabled": true,
            "tags": []
        }))
        .expect_status(200)
        .await;

    // Proxy again — should now go to mock_b (cache was invalidated).
    let req = http::Request::builder()
        .method(Method::GET)
        .uri("/crud-invalidation/v1/models")
        .body(Body::Empty)
        .unwrap();
    let response = h.facade().proxy_request(ctx.clone(), req).await.unwrap();
    assert_eq!(response.status(), StatusCode::OK);
    assert!(
        !mock_b.recorded_requests().await.is_empty(),
        "mock_b should have received at least 1 request after update"
    );
}

// Demonstrate MockGuard pattern for custom per-test responses
#[tokio::test]
async fn proxy_with_mock_guard_custom_response() {
    // Create a MockGuard for test-isolated mock responses
    let mut guard = MockGuard::new();

    // Register a custom response at a unique path
    guard.mock(
        "POST",
        "/custom/endpoint",
        MockResponse {
            status: 200,
            headers: vec![("content-type".into(), "application/json".into())],
            body: MockBody::Json(json!({
                "custom": "response",
                "test": "data"
            })),
        },
    );

    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    // Create upstream pointing to mock server
    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("guard-test")
            .build(),
        )
        .await
        .unwrap();

    // Create route using the guard's prefixed path
    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Post],
                        path: guard.path("/custom/endpoint"),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Disabled,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    // Make request to the prefixed path
    let req = http::Request::builder()
        .method(Method::POST)
        .uri(format!("/guard-test{}", guard.path("/custom/endpoint")))
        .header(http::header::CONTENT_TYPE, "application/json")
        .body(Body::from(r#"{"test":"input"}"#))
        .unwrap();

    let response = h.facade().proxy_request(ctx.clone(), req).await.unwrap();
    assert_eq!(response.status(), StatusCode::OK);

    let body_bytes = response.into_body().into_bytes().await.unwrap();
    let body_json: serde_json::Value = serde_json::from_slice(&body_bytes).unwrap();
    assert_eq!(body_json["custom"], "response");
    assert_eq!(body_json["test"], "data");

    // Verify request was recorded (filtered by guard prefix)
    let recorded = guard.recorded_requests().await;
    assert_eq!(recorded.len(), 1);
    assert!(recorded[0].uri.contains("/custom/endpoint"));
}

// WebSocket upgrade request returns 101 Switching Protocols when upstream accepts.
#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
async fn proxy_websocket_upgrade_returns_101() {
    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("ws-echo-test")
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Get],
                        path: "/ws/echo".into(),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Append,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    // Send a WebSocket upgrade request through the data plane.
    // The mock server has a ws_echo handler at /ws/echo.
    let req = http::Request::builder()
        .method(Method::GET)
        .uri("/ws-echo-test/ws/echo")
        .header("upgrade", "websocket")
        .header("connection", "Upgrade")
        .header("sec-websocket-key", "dGhlIHNhbXBsZSBub25jZQ==")
        .header("sec-websocket-version", "13")
        .body(Body::Empty)
        .unwrap();

    let resp = h
        .facade()
        .proxy_request(ctx.clone(), req)
        .await
        .expect("WebSocket upgrade should succeed");

    assert_eq!(
        resp.status(),
        http::StatusCode::SWITCHING_PROTOCOLS,
        "expected 101, got {}",
        resp.status()
    );
    assert_eq!(
        resp.headers().get("upgrade").and_then(|v| v.to_str().ok()),
        Some("websocket"),
        "response should contain Upgrade: websocket header"
    );
}

// WebSocket upgrade rejected by upstream returns 502 ProtocolError with gateway error source.
#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
async fn proxy_websocket_upgrade_rejected_returns_502_protocol_error() {
    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    // Point at /v1/models — a plain GET endpoint, not a WebSocket handler.
    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("ws-reject-test")
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Get],
                        path: "/v1/models".into(),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Append,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    // Send a WebSocket upgrade request to the non-WebSocket upstream.
    let req = http::Request::builder()
        .method(Method::GET)
        .uri("/ws-reject-test/v1/models")
        .header("upgrade", "websocket")
        .header("connection", "Upgrade")
        .header("sec-websocket-key", "dGhlIHNhbXBsZSBub25jZQ==")
        .header("sec-websocket-version", "13")
        .body(Body::Empty)
        .unwrap();

    let err = h
        .facade()
        .proxy_request(ctx, req)
        .await
        .expect_err("expected ProtocolError for rejected WebSocket upgrade");

    assert!(
        matches!(
            err,
            oagw_sdk::error::ServiceGatewayError::ProtocolError { .. }
        ),
        "expected ProtocolError, got {err:?}"
    );
}

// WebSocket E2E: upgrade through real TCP, send text frame, receive echo.
#[tokio::test(flavor = "multi_thread", worker_threads = 4)]
async fn proxy_websocket_e2e_echo() {
    use tokio::io::AsyncWriteExt;

    let h = AppHarness::builder().build().await;
    setup_ws_upstream(&h, "ws-e2e").await;
    let (addr, server_handle) = start_oagw_server(&h).await;

    let mut stream = tokio::net::TcpStream::connect(addr).await.unwrap();
    ws_handshake(&mut stream, "/oagw/v1/proxy/ws-e2e/ws/echo").await;

    // Send a masked text frame containing "hello" and read the echo.
    let frame = build_masked_frame(0x1, b"hello");
    stream.write_all(&frame).await.unwrap();
    let (opcode, payload) = read_ws_frame(&mut stream).await.expect("echo frame");
    assert_eq!(opcode, 0x1, "expected text frame opcode");
    assert_eq!(payload, b"hello", "echoed payload mismatch");

    // Send a close frame with code 1000 (Normal Closure).
    let close_frame = build_masked_frame(0x8, &1000u16.to_be_bytes());
    stream.write_all(&close_frame).await.unwrap();
    if let Some((op, _)) = read_ws_frame(&mut stream).await {
        assert_eq!(op, 0x8, "expected close frame opcode");
    }

    server_handle.abort();
}

// 14.2: Auth credentials are injected into the outbound WebSocket upgrade request.
#[tokio::test]
async fn proxy_websocket_auth_injected_during_handshake() {
    let mut guard = MockGuard::new();
    guard.mock(
        "GET",
        "/ws/echo",
        MockResponse {
            status: 200,
            headers: vec![("content-type".into(), "application/json".into())],
            body: MockBody::Json(json!({"ok": true})),
        },
    );

    let h = AppHarness::builder()
        .with_credentials(vec![("cred://ws-key".into(), "sk-ws-secret".into())])
        .build()
        .await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("ws-auth-test")
            .auth(oagw_sdk::AuthConfig {
                plugin_type: APIKEY_AUTH_PLUGIN_ID.into(),
                sharing: SharingMode::Private,
                config: Some(
                    [
                        ("header".into(), "authorization".into()),
                        ("prefix".into(), "Bearer ".into()),
                        ("secret_ref".into(), "cred://ws-key".into()),
                    ]
                    .into_iter()
                    .collect(),
                ),
            })
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Get],
                        path: guard.path("/ws/echo"),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Append,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    let req = http::Request::builder()
        .method(Method::GET)
        .uri(format!("/ws-auth-test{}", guard.path("/ws/echo")))
        .header("upgrade", "websocket")
        .header("connection", "Upgrade")
        .header("sec-websocket-key", "dGhlIHNhbXBsZSBub25jZQ==")
        .header("sec-websocket-version", "13")
        .body(Body::Empty)
        .unwrap();

    // The MockGuard returns 200 (it can't do a real WebSocket handshake),
    // so the proxy correctly returns ProtocolError. The upgrade request was
    // already sent to upstream before the response is checked, so
    // guard.recorded_requests() still captures the outbound headers we need.
    let err = h
        .facade()
        .proxy_request(ctx, req)
        .await
        .expect_err("mock returns 200, so upgrade should fail with ProtocolError");
    assert!(
        matches!(
            err,
            oagw_sdk::error::ServiceGatewayError::ProtocolError { .. }
        ),
        "expected ProtocolError, got {err:?}"
    );

    let recorded = guard.recorded_requests().await;
    assert_eq!(recorded.len(), 1, "expected exactly 1 recorded request");

    // Verify the auth plugin injected credentials into the upgrade request.
    let auth_header = recorded[0]
        .headers
        .iter()
        .find(|(k, _)| k == "authorization")
        .map(|(_, v)| v.as_str())
        .expect("authorization header missing from upgrade request");
    assert_eq!(auth_header, "Bearer sk-ws-secret");

    // Verify WebSocket-specific headers were forwarded (not stripped by auth pipeline).
    let has_upgrade = recorded[0]
        .headers
        .iter()
        .any(|(k, v)| k == "upgrade" && v == "websocket");
    assert!(has_upgrade, "Upgrade header missing from outbound request");

    let has_ws_key = recorded[0]
        .headers
        .iter()
        .any(|(k, _)| k == "sec-websocket-key");
    assert!(
        has_ws_key,
        "Sec-WebSocket-Key header missing from outbound request"
    );
}

// 14.3: Rate limiting applies to WebSocket connection establishment.
#[tokio::test]
async fn proxy_websocket_rate_limit_on_handshake() {
    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("ws-rate-limit")
            .rate_limit(RateLimitConfig {
                sharing: SharingMode::Private,
                algorithm: RateLimitAlgorithm::TokenBucket,
                sustained: SustainedRate {
                    rate: 1,
                    window: Window::Minute,
                },
                burst: Some(BurstConfig { capacity: 1 }),
                scope: RateLimitScope::Tenant,
                strategy: RateLimitStrategy::Reject,
                cost: 1,
            })
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Get],
                        path: "/ws/echo".into(),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Append,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    // First WebSocket upgrade should succeed.
    let req = http::Request::builder()
        .method(Method::GET)
        .uri("/ws-rate-limit/ws/echo")
        .header("upgrade", "websocket")
        .header("connection", "Upgrade")
        .header("sec-websocket-key", "dGhlIHNhbXBsZSBub25jZQ==")
        .header("sec-websocket-version", "13")
        .body(Body::Empty)
        .unwrap();
    let response = h.facade().proxy_request(ctx.clone(), req).await.unwrap();
    assert_eq!(
        response.status(),
        StatusCode::SWITCHING_PROTOCOLS,
        "first WS upgrade should succeed with 101"
    );

    // Second WebSocket upgrade within the rate window should be rejected.
    let req = http::Request::builder()
        .method(Method::GET)
        .uri("/ws-rate-limit/ws/echo")
        .header("upgrade", "websocket")
        .header("connection", "Upgrade")
        .header("sec-websocket-key", "dGhlIHNhbXBsZSBub25jZQ==")
        .header("sec-websocket-version", "13")
        .body(Body::Empty)
        .unwrap();
    match h.facade().proxy_request(ctx, req).await {
        Err(err) => assert!(
            matches!(
                err,
                oagw_sdk::error::ServiceGatewayError::RateLimitExceeded { .. }
            ),
            "expected RateLimitExceeded, got: {err:?}"
        ),
        Ok(resp) => panic!(
            "expected rate limit error on second WS upgrade, got status {}",
            resp.status()
        ),
    }
}

// 14.4: WebSocket idle timeout — gateway closes the connection after inactivity.
#[tokio::test(flavor = "multi_thread", worker_threads = 4)]
async fn proxy_websocket_idle_timeout_closes_connection() {
    use tokio::io::AsyncWriteExt;

    let h = AppHarness::builder()
        .with_websocket_idle_timeout(std::time::Duration::from_secs(1))
        .build()
        .await;
    setup_ws_upstream(&h, "ws-idle-timeout").await;
    let (addr, server_handle) = start_oagw_server(&h).await;

    let mut stream = tokio::net::TcpStream::connect(addr).await.unwrap();
    ws_handshake(&mut stream, "/oagw/v1/proxy/ws-idle-timeout/ws/echo").await;

    // Send a text frame to prove the connection is alive.
    let frame = build_masked_frame(0x1, b"ping");
    stream.write_all(&frame).await.unwrap();
    let (opcode, _) = read_ws_frame(&mut stream).await.expect("echo frame");
    assert_eq!(opcode, 0x1, "expected text frame opcode");

    // Wait longer than the idle timeout (1s).
    tokio::time::sleep(std::time::Duration::from_secs(2)).await;

    // Expect EOF or close frame indicating gateway closed the connection.
    if let Some((op, _)) = read_ws_frame(&mut stream).await {
        // Close frame received; EOF (None) is also valid — gateway closed TCP.
        assert_eq!(op, 0x8, "expected close frame after idle timeout");
    }

    server_handle.abort();
}

// P4 #18: Pingora fail_to_proxy produces valid RFC 9457 Problem body with correct GTS type.
#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
async fn proxy_unreachable_backend_returns_rfc9457_problem_body() {
    let h = AppHarness::builder()
        .with_request_timeout(std::time::Duration::from_secs(5))
        .build()
        .await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: 19993,
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("rfc9457-body-test")
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Get],
                        path: "/v1/test".into(),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Append,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    let req = http::Request::builder()
        .method(Method::GET)
        .uri("/rfc9457-body-test/v1/test")
        .body(Body::Empty)
        .unwrap();

    match h.facade().proxy_request(ctx.clone(), req).await {
        Err(err) => {
            // Went through DomainError path — already covered by other tests.
            // Still verify the variant is one of the two expected for an
            // unreachable backend (not e.g. ValidationError which would be a bug).
            assert!(
                matches!(
                    err,
                    oagw_sdk::error::ServiceGatewayError::DownstreamError { .. }
                        | oagw_sdk::error::ServiceGatewayError::ConnectionTimeout { .. }
                        | oagw_sdk::error::ServiceGatewayError::RequestTimeout { .. }
                ),
                "expected DownstreamError, ConnectionTimeout, or RequestTimeout for unreachable backend, got: {err:?}"
            );
        }
        Ok(resp) => {
            // Pingora wrote the response directly via fail_to_proxy.
            let status = resp.status();
            assert!(
                status == StatusCode::BAD_GATEWAY || status == StatusCode::GATEWAY_TIMEOUT,
                "expected 502 or 504, got: {status}"
            );

            let body_bytes = resp.into_body().into_bytes().await.unwrap();
            let body: serde_json::Value = serde_json::from_slice(&body_bytes)
                .expect("fail_to_proxy response body should be valid JSON");

            // Must have all RFC 9457 Problem fields.
            assert!(body.get("type").is_some(), "missing 'type' field");
            assert!(body.get("title").is_some(), "missing 'title' field");
            assert!(body.get("status").is_some(), "missing 'status' field");
            assert!(body.get("detail").is_some(), "missing 'detail' field");
            assert!(body.get("instance").is_some(), "missing 'instance' field");

            // GTS type must not be about:blank.
            let gts_type = body["type"].as_str().unwrap();
            assert!(
                gts_type.starts_with("gts."),
                "expected GTS error type, got: {gts_type}"
            );

            // Status field in body must match HTTP status.
            assert_eq!(
                body["status"].as_u64().unwrap(),
                status.as_u16() as u64,
                "body status must match HTTP status"
            );
        }
    }
}

// negative-8.1 (body-validation): Streaming body exceeding max_body_size returns 413 PayloadTooLarge.
#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
async fn proxy_streaming_body_exceeding_limit_returns_413() {
    let mut guard = MockGuard::new();
    guard.mock(
        "POST",
        "/v1/upload",
        MockResponse {
            status: 200,
            headers: vec![],
            body: MockBody::Json(serde_json::json!({"ok": true})),
        },
    );

    let h = AppHarness::builder()
        .with_max_body_size(64) // tiny limit for testing
        .build()
        .await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("body-limit-test")
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Post],
                        path: guard.path("/v1/upload"),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Disabled,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    // Build a streaming body that exceeds the 64-byte limit.
    let chunks: Vec<Result<bytes::Bytes, oagw_sdk::body::BoxError>> = vec![
        Ok(bytes::Bytes::from(vec![b'A'; 40])),
        Ok(bytes::Bytes::from(vec![b'B'; 40])), // total = 80 > 64
    ];
    let stream: oagw_sdk::body::BodyStream = Box::pin(futures_util::stream::iter(chunks));
    let body = Body::Stream(stream);

    let req = http::Request::builder()
        .method(Method::POST)
        .uri(format!("/body-limit-test{}/v1/upload", guard.prefix()))
        .header(http::header::CONTENT_TYPE, "application/octet-stream")
        .body(body)
        .unwrap();

    match h.facade().proxy_request(ctx.clone(), req).await {
        Err(err) => assert!(
            matches!(
                err,
                oagw_sdk::error::ServiceGatewayError::PayloadTooLarge { .. }
            ),
            "expected PayloadTooLarge, got: {err:?}"
        ),
        Ok(resp) => panic!(
            "expected PayloadTooLarge error, got response with status {}",
            resp.status()
        ),
    }
}

// Body::Stream POST must reach the upstream intact via chunked transfer
// encoding on the internal Pingora bridge.
#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
async fn proxy_streaming_body_post_arrives_intact() {
    let mut guard = MockGuard::new();
    guard.mock(
        "POST",
        "/v1/upload",
        MockResponse {
            status: 200,
            headers: vec![],
            body: MockBody::Json(serde_json::json!({"received": true})),
        },
    );

    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("stream-body-test")
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Post],
                        path: guard.path("/v1/upload"),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Disabled,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    // Build a multi-chunk streaming body (simulates multipart/streaming upload).
    let chunk_a = bytes::Bytes::from_static(b"hello ");
    let chunk_b = bytes::Bytes::from_static(b"streamed ");
    let chunk_c = bytes::Bytes::from_static(b"world");
    let chunks: Vec<Result<bytes::Bytes, oagw_sdk::body::BoxError>> =
        vec![Ok(chunk_a), Ok(chunk_b), Ok(chunk_c)];
    let stream: oagw_sdk::body::BodyStream = Box::pin(futures_util::stream::iter(chunks));
    let body = Body::Stream(stream);

    let req = http::Request::builder()
        .method(Method::POST)
        .uri(format!("/stream-body-test{}/v1/upload", guard.prefix()))
        .header(http::header::CONTENT_TYPE, "application/octet-stream")
        .body(body)
        .unwrap();

    let resp = h.facade().proxy_request(ctx.clone(), req).await.unwrap();
    assert_eq!(
        resp.status(),
        StatusCode::OK,
        "streaming POST should succeed"
    );

    // Verify the upstream mock received the complete, reassembled body.
    let recorded = guard.recorded_requests().await;
    assert_eq!(recorded.len(), 1, "expected exactly one recorded request");
    assert_eq!(
        recorded[0].body, b"hello streamed world",
        "upstream must receive the full concatenated streaming body"
    );
}

// Empty chunks in a Body::Stream must be silently skipped — writing a
// zero-length chunk would emit the chunked terminator (0\r\n\r\n) and
// prematurely end the body.
#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
async fn proxy_streaming_body_with_empty_chunks_succeeds() {
    let mut guard = MockGuard::new();
    guard.mock(
        "POST",
        "/v1/upload-empty",
        MockResponse {
            status: 200,
            headers: vec![],
            body: MockBody::Json(serde_json::json!({"received": true})),
        },
    );

    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("stream-empty-chunks")
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Post],
                        path: guard.path("/v1/upload-empty"),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Disabled,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    // Interleave real chunks with empty ones.
    let chunks: Vec<Result<bytes::Bytes, oagw_sdk::body::BoxError>> = vec![
        Ok(bytes::Bytes::new()), // empty — must be skipped
        Ok(bytes::Bytes::from_static(b"AB")),
        Ok(bytes::Bytes::new()), // empty — must be skipped
        Ok(bytes::Bytes::new()), // empty — must be skipped
        Ok(bytes::Bytes::from_static(b"CD")),
        Ok(bytes::Bytes::new()), // trailing empty
    ];
    let stream: oagw_sdk::body::BodyStream = Box::pin(futures_util::stream::iter(chunks));
    let body = Body::Stream(stream);

    let req = http::Request::builder()
        .method(Method::POST)
        .uri(format!(
            "/stream-empty-chunks{}/v1/upload-empty",
            guard.prefix()
        ))
        .header(http::header::CONTENT_TYPE, "application/octet-stream")
        .body(body)
        .unwrap();

    let resp = h.facade().proxy_request(ctx.clone(), req).await.unwrap();
    assert_eq!(
        resp.status(),
        StatusCode::OK,
        "streaming POST with empty chunks should succeed"
    );

    let recorded = guard.recorded_requests().await;
    assert_eq!(recorded.len(), 1, "expected exactly one recorded request");
    assert_eq!(
        recorded[0].body, b"ABCD",
        "upstream must receive only the non-empty chunks, concatenated"
    );
}

// Single-chunk streaming body (boundary condition).
#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
async fn proxy_streaming_body_single_chunk() {
    let mut guard = MockGuard::new();
    guard.mock(
        "POST",
        "/v1/upload",
        MockResponse {
            status: 200,
            headers: vec![],
            body: MockBody::Json(serde_json::json!({"received": true})),
        },
    );

    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("stream-single-chunk")
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Post],
                        path: guard.path("/v1/upload"),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Disabled,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    let chunks: Vec<Result<bytes::Bytes, oagw_sdk::body::BoxError>> =
        vec![Ok(bytes::Bytes::from_static(b"single-payload"))];
    let stream: oagw_sdk::body::BodyStream = Box::pin(futures_util::stream::iter(chunks));
    let body = Body::Stream(stream);

    let req = http::Request::builder()
        .method(Method::POST)
        .uri(format!("/stream-single-chunk{}/v1/upload", guard.prefix()))
        .header(http::header::CONTENT_TYPE, "application/octet-stream")
        .body(body)
        .unwrap();

    let resp = h.facade().proxy_request(ctx.clone(), req).await.unwrap();
    assert_eq!(
        resp.status(),
        StatusCode::OK,
        "single-chunk streaming POST should succeed"
    );

    let recorded = guard.recorded_requests().await;
    assert_eq!(recorded.len(), 1, "expected exactly one recorded request");
    assert_eq!(
        recorded[0].body, b"single-payload",
        "upstream must receive the single chunk intact"
    );
}

// A stream error mid-body sends the cause on the abort channel so the chunked
// terminator is NOT written.  The main select! receives the reason immediately,
// returning a DownstreamError without waiting for the request timeout.
#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
async fn proxy_streaming_body_error_mid_stream_does_not_send_terminator() {
    let mut guard = MockGuard::new();
    guard.mock(
        "POST",
        "/v1/upload-err",
        MockResponse {
            status: 200,
            headers: vec![],
            body: MockBody::Json(serde_json::json!({"received": true})),
        },
    );

    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("stream-err-test")
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Post],
                        path: guard.path("/v1/upload-err"),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Disabled,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    // First chunk succeeds, second chunk is an error — triggers the abort channel.
    let chunks: Vec<Result<bytes::Bytes, oagw_sdk::body::BoxError>> = vec![
        Ok(bytes::Bytes::from_static(b"partial")),
        Err(Box::new(std::io::Error::other("simulated stream failure"))),
    ];
    let stream: oagw_sdk::body::BodyStream = Box::pin(futures_util::stream::iter(chunks));
    let body = Body::Stream(stream);

    let req = http::Request::builder()
        .method(Method::POST)
        .uri(format!("/stream-err-test{}/v1/upload-err", guard.prefix()))
        .header(http::header::CONTENT_TYPE, "application/octet-stream")
        .body(body)
        .unwrap();

    match h.facade().proxy_request(ctx.clone(), req).await {
        Err(err) => assert!(
            matches!(
                err,
                oagw_sdk::error::ServiceGatewayError::DownstreamError { .. }
            ),
            "expected DownstreamError, got: {err:?}"
        ),
        Ok(resp) => panic!(
            "expected DownstreamError, got response with status {}",
            resp.status()
        ),
    }
}

// ---------------------------------------------------------------------------
// OAuth2 Client Credentials integration tests
// ---------------------------------------------------------------------------

/// 9.5: OAuth2 CC happy path — token fetched from mock IdP, injected as Bearer.
#[tokio::test]
async fn proxy_oauth2_client_cred_injects_bearer_token() {
    let mut guard = MockGuard::new();

    // Mock token endpoint on the same shared mock server.
    guard.mock(
        "POST",
        "/oauth/token",
        MockResponse {
            status: 200,
            headers: vec![("content-type".into(), "application/json".into())],
            body: MockBody::Json(
                json!({"access_token":"tok-oauth2-test","expires_in":3600,"token_type":"Bearer"}),
            ),
        },
    );

    // Mock upstream API endpoint.
    guard.mock(
        "GET",
        "/api/resource",
        MockResponse {
            status: 200,
            headers: vec![("content-type".into(), "application/json".into())],
            body: MockBody::Json(json!({"status":"ok"})),
        },
    );

    let h = AppHarness::builder()
        .with_credentials(vec![
            ("cred://oauth2-client-id".into(), "test-id".into()),
            ("cred://oauth2-client-secret".into(), "test-secret".into()),
        ])
        .build()
        .await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("oauth2-test")
            .auth(oagw_sdk::AuthConfig {
                plugin_type: OAUTH2_CLIENT_CRED_AUTH_PLUGIN_ID.into(),
                sharing: SharingMode::Private,
                config: Some(
                    [
                        (
                            "token_endpoint".into(),
                            format!(
                                "http://127.0.0.1:{}{}",
                                h.mock_port(),
                                guard.path("/oauth/token")
                            ),
                        ),
                        ("client_id_ref".into(), "cred://oauth2-client-id".into()),
                        (
                            "client_secret_ref".into(),
                            "cred://oauth2-client-secret".into(),
                        ),
                    ]
                    .into_iter()
                    .collect(),
                ),
            })
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Get],
                        path: guard.path("/api/resource"),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Disabled,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    let req = http::Request::builder()
        .method(Method::GET)
        .uri(format!("/oauth2-test{}", guard.path("/api/resource")))
        .body(Body::Empty)
        .unwrap();
    let response = h.facade().proxy_request(ctx, req).await.unwrap();

    assert_eq!(response.status(), StatusCode::OK);

    // Verify the upstream received the Bearer token from the OAuth2 flow.
    let recorded = guard.recorded_requests().await;
    let api_request = recorded
        .iter()
        .find(|r| r.uri.contains("/api/resource"))
        .expect("upstream API request not found");
    let auth_header = api_request
        .headers
        .iter()
        .find(|(k, _)| k == "authorization")
        .map(|(_, v)| v.as_str())
        .expect("authorization header missing");
    assert_eq!(auth_header, "Bearer tok-oauth2-test");
}

/// 9.5: OAuth2 CC with missing credentials — credstore returns not found.
#[tokio::test]
async fn proxy_oauth2_missing_credentials_returns_error() {
    let mut guard = MockGuard::new();
    guard.mock(
        "GET",
        "/api/resource",
        MockResponse {
            status: 200,
            headers: vec![],
            body: MockBody::Json(json!({"status":"ok"})),
        },
    );

    // No credentials loaded for the OAuth2 refs.
    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("oauth2-missing-creds")
            .auth(oagw_sdk::AuthConfig {
                plugin_type: OAUTH2_CLIENT_CRED_AUTH_PLUGIN_ID.into(),
                sharing: SharingMode::Private,
                config: Some(
                    [
                        (
                            "token_endpoint".into(),
                            format!(
                                "http://127.0.0.1:{}{}",
                                h.mock_port(),
                                guard.path("/oauth/token")
                            ),
                        ),
                        ("client_id_ref".into(), "cred://missing-id".into()),
                        ("client_secret_ref".into(), "cred://missing-secret".into()),
                    ]
                    .into_iter()
                    .collect(),
                ),
            })
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Get],
                        path: guard.path("/api/resource"),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Disabled,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    let req = http::Request::builder()
        .method(Method::GET)
        .uri(format!(
            "/oauth2-missing-creds{}",
            guard.path("/api/resource")
        ))
        .body(Body::Empty)
        .unwrap();
    let response = h.facade().proxy_request(ctx, req).await;

    // Should fail with a secret-not-found error.
    assert!(response.is_err());
}

// ---------------------------------------------------------------------------
// Guard plugin integration tests
// ---------------------------------------------------------------------------

const REQUIRED_HEADERS_GUARD_PLUGIN_ID: &str =
    "gts.x.core.oagw.guard_plugin.v1~x.core.oagw.required_headers.v1";

/// Verify that the RequiredHeadersGuardPlugin allows requests that include
/// all required headers.
#[tokio::test]
async fn proxy_guard_allows_when_required_header_present() {
    let mut guard = MockGuard::new();
    guard.mock(
        "POST",
        "/guard-hdr-ok",
        MockResponse {
            status: 200,
            headers: vec![("content-type".into(), "application/json".into())],
            body: MockBody::Json(json!({"ok": true})),
        },
    );

    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("guard-hdr-ok")
            .headers(HeadersConfig {
                request: Some(RequestHeaderRules {
                    passthrough: PassthroughMode::All,
                    ..Default::default()
                }),
                response: None,
            })
            .plugins(PluginsConfig {
                sharing: SharingMode::Private,
                items: vec![PluginBinding {
                    plugin_ref: REQUIRED_HEADERS_GUARD_PLUGIN_ID.to_string(),
                    config: [("required_request_headers".into(), "x-correlation-id".into())].into(),
                }],
            })
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Post],
                        path: guard.path("/guard-hdr-ok"),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Disabled,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    let req = http::Request::builder()
        .method(Method::POST)
        .uri(format!("/guard-hdr-ok{}", guard.path("/guard-hdr-ok")))
        .header(http::header::CONTENT_TYPE, "application/json")
        .header("x-correlation-id", "test-123")
        .body(Body::from(r#"{"test": true}"#))
        .unwrap();

    let response = h.facade().proxy_request(ctx.clone(), req).await.unwrap();
    assert_eq!(response.status(), StatusCode::OK);
}

/// Verify that the RequiredHeadersGuardPlugin rejects requests missing a
/// required header, returning a 400 GuardRejected error.
#[tokio::test]
async fn proxy_guard_rejects_missing_required_header() {
    let mut guard = MockGuard::new();
    guard.mock(
        "POST",
        "/guard-hdr-miss",
        MockResponse {
            status: 200,
            headers: vec![("content-type".into(), "application/json".into())],
            body: MockBody::Json(json!({"ok": true})),
        },
    );

    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("guard-hdr-miss")
            .plugins(PluginsConfig {
                sharing: SharingMode::Private,
                items: vec![PluginBinding {
                    plugin_ref: REQUIRED_HEADERS_GUARD_PLUGIN_ID.to_string(),
                    config: [("required_request_headers".into(), "x-correlation-id".into())].into(),
                }],
            })
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Post],
                        path: guard.path("/guard-hdr-miss"),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Disabled,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    // Send request WITHOUT the required x-correlation-id header.
    let req = http::Request::builder()
        .method(Method::POST)
        .uri(format!("/guard-hdr-miss{}", guard.path("/guard-hdr-miss")))
        .header(http::header::CONTENT_TYPE, "application/json")
        .body(Body::from(r#"{"test": true}"#))
        .unwrap();

    let err = h
        .facade()
        .proxy_request(ctx.clone(), req)
        .await
        .expect_err("guard should reject missing required header");

    match err {
        oagw_sdk::error::ServiceGatewayError::GuardRejected {
            status, error_code, ..
        } => {
            assert_eq!(status, 400);
            assert_eq!(error_code, "REQUIRED_HEADER_MISSING");
        }
        other => panic!("expected GuardRejected, got: {other:?}"),
    }

    // Verify the request never reached the upstream.
    let recorded = guard.recorded_requests().await;
    assert!(
        recorded.is_empty(),
        "rejected request should not reach upstream"
    );
}

/// Verify that an unconfigured RequiredHeadersGuardPlugin allows all requests.
#[tokio::test]
async fn proxy_guard_allows_unconfigured() {
    let mut guard = MockGuard::new();
    guard.mock(
        "POST",
        "/guard-hdr-noconf",
        MockResponse {
            status: 200,
            headers: vec![("content-type".into(), "application/json".into())],
            body: MockBody::Json(json!({"ok": true})),
        },
    );

    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("guard-hdr-noconf")
            .plugins(PluginsConfig {
                sharing: SharingMode::Private,
                items: vec![PluginBinding {
                    plugin_ref: REQUIRED_HEADERS_GUARD_PLUGIN_ID.to_string(),
                    config: HashMap::new(),
                }],
            })
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Post],
                        path: guard.path("/guard-hdr-noconf"),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Disabled,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    let req = http::Request::builder()
        .method(Method::POST)
        .uri(format!(
            "/guard-hdr-noconf{}",
            guard.path("/guard-hdr-noconf")
        ))
        .header(http::header::CONTENT_TYPE, "application/json")
        .body(Body::from(r#"{"test": true}"#))
        .unwrap();

    let response = h.facade().proxy_request(ctx.clone(), req).await.unwrap();
    assert_eq!(response.status(), StatusCode::OK);
}

// ---------------------------------------------------------------------------
// Transform plugin integration tests
// ---------------------------------------------------------------------------

const REQUEST_ID_TRANSFORM_PLUGIN_ID: &str =
    "gts.x.core.oagw.transform_plugin.v1~x.core.oagw.request_id.v1";

/// Verify that the RequestIdTransformPlugin injects an X-Request-ID header when
/// the inbound request does not include one.
#[tokio::test]
async fn proxy_transform_injects_request_id() {
    let mut guard = MockGuard::new();
    guard.mock(
        "POST",
        "/transform-test",
        MockResponse {
            status: 200,
            headers: vec![("content-type".into(), "application/json".into())],
            body: MockBody::Json(json!({"ok": true})),
        },
    );

    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("transform-inject")
            .plugins(PluginsConfig {
                sharing: SharingMode::Private,
                items: vec![PluginBinding {
                    plugin_ref: REQUEST_ID_TRANSFORM_PLUGIN_ID.to_string(),
                    config: Default::default(),
                }],
            })
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Post],
                        path: guard.path("/transform-test"),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Disabled,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    // Send request WITHOUT X-Request-ID.
    let req = http::Request::builder()
        .method(Method::POST)
        .uri(format!(
            "/transform-inject{}",
            guard.path("/transform-test")
        ))
        .header(http::header::CONTENT_TYPE, "application/json")
        .body(Body::from(r#"{"test": true}"#))
        .unwrap();

    let response = h.facade().proxy_request(ctx.clone(), req).await.unwrap();
    assert_eq!(response.status(), StatusCode::OK);

    // The mock upstream should have received the request WITH an X-Request-ID.
    let recorded = guard.recorded_requests().await;
    assert_eq!(recorded.len(), 1);
    let has_request_id = recorded[0]
        .headers
        .iter()
        .any(|(k, _)| k.eq_ignore_ascii_case("x-request-id"));
    assert!(
        has_request_id,
        "upstream should have received x-request-id header injected by transform plugin"
    );
}

/// Verify that the RequestIdTransformPlugin preserves an existing X-Request-ID
/// from the inbound request (does not overwrite it).
#[tokio::test]
async fn proxy_transform_preserves_request_id() {
    let mut guard = MockGuard::new();
    guard.mock(
        "POST",
        "/transform-preserve",
        MockResponse {
            status: 200,
            headers: vec![("content-type".into(), "application/json".into())],
            body: MockBody::Json(json!({"ok": true})),
        },
    );

    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("transform-preserve")
            .headers(HeadersConfig {
                request: Some(RequestHeaderRules {
                    passthrough: PassthroughMode::All,
                    ..Default::default()
                }),
                ..Default::default()
            })
            .plugins(PluginsConfig {
                sharing: SharingMode::Private,
                items: vec![PluginBinding {
                    plugin_ref: REQUEST_ID_TRANSFORM_PLUGIN_ID.to_string(),
                    config: Default::default(),
                }],
            })
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Post],
                        path: guard.path("/transform-preserve"),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Disabled,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    // Send request WITH an existing X-Request-ID.
    let req = http::Request::builder()
        .method(Method::POST)
        .uri(format!(
            "/transform-preserve{}",
            guard.path("/transform-preserve")
        ))
        .header(http::header::CONTENT_TYPE, "application/json")
        .header("x-request-id", "custom-trace-id-999")
        .body(Body::from(r#"{"test": true}"#))
        .unwrap();

    let response = h.facade().proxy_request(ctx.clone(), req).await.unwrap();
    assert_eq!(response.status(), StatusCode::OK);

    // The mock upstream should have received the ORIGINAL X-Request-ID.
    let recorded = guard.recorded_requests().await;
    assert_eq!(recorded.len(), 1);
    let request_id = recorded[0]
        .headers
        .iter()
        .find(|(k, _)| k.eq_ignore_ascii_case("x-request-id"))
        .map(|(_, v)| v.as_str());
    assert_eq!(
        request_id,
        Some("custom-trace-id-999"),
        "upstream should have received the original x-request-id, not a generated one"
    );
}

/// Verify that a failing transform plugin (unknown GTS ID) does not block the
/// proxy pipeline — the request still succeeds (log-and-continue).
#[tokio::test]
async fn proxy_transform_error_continues_pipeline() {
    let mut guard = MockGuard::new();
    guard.mock(
        "POST",
        "/transform-error",
        MockResponse {
            status: 200,
            headers: vec![("content-type".into(), "application/json".into())],
            body: MockBody::Json(json!({"ok": true})),
        },
    );

    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    // Bind a non-existent transform plugin — resolution will fail.
    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("transform-error")
            .plugins(PluginsConfig {
                sharing: SharingMode::Private,
                items: vec![PluginBinding {
                    plugin_ref: "gts.x.core.oagw.transform_plugin.v1~x.core.oagw.nonexistent.v1"
                        .to_string(),
                    config: Default::default(),
                }],
            })
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Post],
                        path: guard.path("/transform-error"),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Disabled,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    // Request should succeed despite the broken transform plugin.
    let req = http::Request::builder()
        .method(Method::POST)
        .uri(format!(
            "/transform-error{}",
            guard.path("/transform-error")
        ))
        .header(http::header::CONTENT_TYPE, "application/json")
        .body(Body::from(r#"{"test": true}"#))
        .unwrap();

    let response = h.facade().proxy_request(ctx.clone(), req).await.unwrap();
    assert_eq!(
        response.status(),
        StatusCode::OK,
        "pipeline should continue despite transform resolution failure"
    );
}

// ---------------------------------------------------------------------------
// CORS integration tests
// ---------------------------------------------------------------------------

fn test_cors_config() -> CorsConfig {
    CorsConfig {
        sharing: SharingMode::Private,
        enabled: true,
        allowed_origins: vec!["https://example.com".to_string()],
        allowed_methods: vec![CorsHttpMethod::Get, CorsHttpMethod::Post],
        expose_headers: vec!["x-request-id".to_string()],
        allow_credentials: false,
    }
}

/// Helper: create an upstream with CORS enabled and a single route pointing at the mock.
async fn setup_cors_upstream(
    h: &AppHarness,
    guard: &MockGuard,
    alias: &str,
    cors: Option<CorsConfig>,
) -> uuid::Uuid {
    let ctx = h.security_context().clone();

    let mut builder = CreateUpstreamRequest::builder(
        Server {
            endpoints: vec![Endpoint {
                scheme: Scheme::Http,
                host: "127.0.0.1".into(),
                port: h.mock_port(),
            }],
        },
        "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
    )
    .alias(alias);

    if let Some(c) = cors {
        builder = builder.cors(c);
    }

    let upstream = h
        .facade()
        .create_upstream(ctx.clone(), builder.build())
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Get, HttpMethod::Post],
                        path: guard.path("/api/data"),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Disabled,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    upstream.id
}

// CORS: Upstream Vary header is preserved alongside CORS Vary header.
#[tokio::test]
async fn cors_actual_request_preserves_upstream_vary() {
    let mut guard = MockGuard::new();
    guard.mock(
        "GET",
        "/api/data",
        MockResponse {
            status: 200,
            headers: vec![
                ("content-type".into(), "application/json".into()),
                ("vary".into(), "Accept-Encoding".into()),
            ],
            body: MockBody::Json(json!({"ok": true})),
        },
    );

    let h = AppHarness::builder().build().await;
    setup_cors_upstream(&h, &guard, "cors-vary", Some(test_cors_config())).await;

    let req = http::Request::builder()
        .method(Method::GET)
        .uri(format!("/cors-vary{}", guard.path("/api/data")))
        .header("origin", "https://example.com")
        .body(Body::Empty)
        .unwrap();

    let response = h
        .facade()
        .proxy_request(h.security_context().clone(), req)
        .await
        .unwrap();
    assert_eq!(response.status(), StatusCode::OK);

    let vary_values: Vec<&str> = response
        .headers()
        .get_all(http::header::VARY)
        .iter()
        .filter_map(|v| v.to_str().ok())
        .collect();

    assert!(
        vary_values.iter().any(|v| v.contains("Accept-Encoding")),
        "upstream Vary: Accept-Encoding must be preserved, got: {vary_values:?}"
    );
    assert!(
        vary_values.iter().any(|v| v.contains("Origin")),
        "CORS Vary: Origin must be present, got: {vary_values:?}"
    );
}

// CORS: Actual request with allowed origin includes CORS headers.
#[tokio::test]
async fn cors_actual_request_includes_headers() {
    let mut guard = MockGuard::new();
    guard.mock(
        "POST",
        "/api/data",
        MockResponse {
            status: 200,
            headers: vec![("content-type".into(), "application/json".into())],
            body: MockBody::Json(json!({"ok": true})),
        },
    );

    let h = AppHarness::builder().build().await;
    setup_cors_upstream(&h, &guard, "cors-actual", Some(test_cors_config())).await;

    let req = http::Request::builder()
        .method(Method::POST)
        .uri(format!("/cors-actual{}", guard.path("/api/data")))
        .header("origin", "https://example.com")
        .header("content-type", "application/json")
        .body(Body::from(r#"{"test": true}"#))
        .unwrap();

    let response = h
        .facade()
        .proxy_request(h.security_context().clone(), req)
        .await
        .unwrap();
    assert_eq!(response.status(), StatusCode::OK);

    let headers = response.headers();
    assert_eq!(
        headers.get("access-control-allow-origin").unwrap(),
        "https://example.com"
    );
    assert_eq!(
        headers.get("access-control-expose-headers").unwrap(),
        "x-request-id"
    );
    assert!(
        headers.get(http::header::VARY).is_some(),
        "Vary header must be present"
    );
}

// CORS: No CORS config means no CORS headers in response.
#[tokio::test]
async fn cors_disabled_no_cors_headers() {
    let mut guard = MockGuard::new();
    guard.mock(
        "GET",
        "/api/data",
        MockResponse {
            status: 200,
            headers: vec![("content-type".into(), "application/json".into())],
            body: MockBody::Json(json!({"ok": true})),
        },
    );

    let h = AppHarness::builder().build().await;
    setup_cors_upstream(&h, &guard, "cors-disabled", None).await;

    let req = http::Request::builder()
        .method(Method::GET)
        .uri(format!("/cors-disabled{}", guard.path("/api/data")))
        .header("origin", "https://example.com")
        .body(Body::Empty)
        .unwrap();

    let response = h
        .facade()
        .proxy_request(h.security_context().clone(), req)
        .await
        .unwrap();
    assert_eq!(response.status(), StatusCode::OK);
    assert!(
        response
            .headers()
            .get("access-control-allow-origin")
            .is_none(),
        "no CORS config should produce no CORS headers"
    );
}

// CORS: Upstream error (500) still includes CORS headers so browsers can read error details.
#[tokio::test]
async fn cors_headers_present_on_upstream_error_response() {
    let mut guard = MockGuard::new();
    guard.mock(
        "GET",
        "/api/data",
        MockResponse {
            status: 500,
            headers: vec![("content-type".into(), "application/json".into())],
            body: MockBody::Json(json!({"error": "internal server error"})),
        },
    );

    let h = AppHarness::builder().build().await;
    setup_cors_upstream(&h, &guard, "cors-err", Some(test_cors_config())).await;

    let req = http::Request::builder()
        .method(Method::GET)
        .uri(format!("/cors-err{}", guard.path("/api/data")))
        .header("origin", "https://example.com")
        .body(Body::Empty)
        .unwrap();

    let response = h
        .facade()
        .proxy_request(h.security_context().clone(), req)
        .await
        .unwrap();
    assert_eq!(response.status(), StatusCode::INTERNAL_SERVER_ERROR);

    assert_eq!(
        response
            .headers()
            .get("access-control-allow-origin")
            .unwrap(),
        "https://example.com",
        "CORS headers must be present even on error responses"
    );
}

// CORS: allow_credentials reflects origin and sets credentials header.
#[tokio::test]
async fn cors_credentials_reflects_origin() {
    let mut guard = MockGuard::new();
    guard.mock(
        "GET",
        "/api/data",
        MockResponse {
            status: 200,
            headers: vec![("content-type".into(), "application/json".into())],
            body: MockBody::Json(json!({"ok": true})),
        },
    );

    let h = AppHarness::builder().build().await;
    let cors = CorsConfig {
        allow_credentials: true,
        ..test_cors_config()
    };
    setup_cors_upstream(&h, &guard, "cors-creds", Some(cors)).await;

    let req = http::Request::builder()
        .method(Method::GET)
        .uri(format!("/cors-creds{}", guard.path("/api/data")))
        .header("origin", "https://example.com")
        .body(Body::Empty)
        .unwrap();

    let response = h
        .facade()
        .proxy_request(h.security_context().clone(), req)
        .await
        .unwrap();
    assert_eq!(response.status(), StatusCode::OK);

    let headers = response.headers();
    assert_eq!(
        headers.get("access-control-allow-origin").unwrap(),
        "https://example.com",
        "credentials mode must reflect origin, not wildcard"
    );
    assert_eq!(
        headers.get("access-control-allow-credentials").unwrap(),
        "true"
    );
}

// CORS: Wildcard origin returns literal "*".
#[tokio::test]
async fn cors_wildcard_origin_returns_star() {
    let mut guard = MockGuard::new();
    guard.mock(
        "GET",
        "/api/data",
        MockResponse {
            status: 200,
            headers: vec![("content-type".into(), "application/json".into())],
            body: MockBody::Json(json!({"ok": true})),
        },
    );

    let h = AppHarness::builder().build().await;
    let cors = CorsConfig {
        allowed_origins: vec!["*".to_string()],
        ..test_cors_config()
    };
    setup_cors_upstream(&h, &guard, "cors-wildcard", Some(cors)).await;

    let req = http::Request::builder()
        .method(Method::GET)
        .uri(format!("/cors-wildcard{}", guard.path("/api/data")))
        .header("origin", "https://anything.example.com")
        .body(Body::Empty)
        .unwrap();

    let response = h
        .facade()
        .proxy_request(h.security_context().clone(), req)
        .await
        .unwrap();
    assert_eq!(response.status(), StatusCode::OK);

    assert_eq!(
        response
            .headers()
            .get("access-control-allow-origin")
            .unwrap(),
        "*",
        "wildcard config must return literal '*'"
    );
}

// CORS: Route-level CORS with Inherit merges origins from upstream.
#[tokio::test]
async fn cors_route_inherit_merges_origins() {
    let mut guard = MockGuard::new();
    guard.mock(
        "GET",
        "/api/data",
        MockResponse {
            status: 200,
            headers: vec![("content-type".into(), "application/json".into())],
            body: MockBody::Json(json!({"ok": true})),
        },
    );

    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    // Upstream allows https://example.com
    let upstream_cors = test_cors_config();
    let mut builder = CreateUpstreamRequest::builder(
        Server {
            endpoints: vec![Endpoint {
                scheme: Scheme::Http,
                host: "127.0.0.1".into(),
                port: h.mock_port(),
            }],
        },
        "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
    )
    .alias("cors-route-inherit");
    builder = builder.cors(upstream_cors);

    let upstream = h
        .facade()
        .create_upstream(ctx.clone(), builder.build())
        .await
        .unwrap();

    // Route adds https://other.com via Inherit sharing.
    let route_cors = CorsConfig {
        sharing: SharingMode::Inherit,
        enabled: true,
        allowed_origins: vec!["https://other.com".to_string()],
        allowed_methods: vec![CorsHttpMethod::Get, CorsHttpMethod::Post],
        expose_headers: vec!["x-request-id".to_string()],
        allow_credentials: false,
    };

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Get, HttpMethod::Post],
                        path: guard.path("/api/data"),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Disabled,
                    }),
                    grpc: None,
                },
            )
            .cors(route_cors)
            .build(),
        )
        .await
        .unwrap();

    // Request from the route-added origin should be allowed.
    let req = http::Request::builder()
        .method(Method::GET)
        .uri(format!("/cors-route-inherit{}", guard.path("/api/data")))
        .header("origin", "https://other.com")
        .body(Body::Empty)
        .unwrap();

    let response = h.facade().proxy_request(ctx.clone(), req).await.unwrap();
    assert_eq!(response.status(), StatusCode::OK);
    assert_eq!(
        response
            .headers()
            .get("access-control-allow-origin")
            .unwrap(),
        "https://other.com",
        "route-level Inherit origin must be allowed"
    );

    // Request from the upstream origin should also still be allowed.
    let req = http::Request::builder()
        .method(Method::GET)
        .uri(format!("/cors-route-inherit{}", guard.path("/api/data")))
        .header("origin", "https://example.com")
        .body(Body::Empty)
        .unwrap();

    let response = h.facade().proxy_request(ctx.clone(), req).await.unwrap();
    assert_eq!(response.status(), StatusCode::OK);
    assert_eq!(
        response
            .headers()
            .get("access-control-allow-origin")
            .unwrap(),
        "https://example.com",
        "upstream origin must still be allowed after route Inherit merge"
    );
}

// CORS: Disallowed origin is rejected before reaching upstream.
#[tokio::test]
async fn cors_actual_request_disallowed_origin_rejected_before_upstream() {
    let guard = MockGuard::new();
    // No mock registered — if the upstream is called, the request will fail differently.

    let h = AppHarness::builder().build().await;
    setup_cors_upstream(&h, &guard, "cors-reject-origin", Some(test_cors_config())).await;

    let req = http::Request::builder()
        .method(Method::GET)
        .uri(format!("/cors-reject-origin{}", guard.path("/api/data")))
        .header("origin", "https://evil.com")
        .body(Body::Empty)
        .unwrap();

    let response = h
        .facade()
        .proxy_request(h.security_context().clone(), req)
        .await;
    assert!(
        response.is_err(),
        "disallowed origin on actual request should be rejected before reaching upstream"
    );
}

// CORS: Disallowed method is rejected before reaching upstream.
#[tokio::test]
async fn cors_actual_request_disallowed_method_rejected_before_upstream() {
    let guard = MockGuard::new();
    // No mock registered — if the upstream is called, the request will fail differently.

    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    // Route allows DELETE but CORS config only allows GET and POST.
    let cors = test_cors_config(); // allowed_methods: [Get, Post]

    let mut builder = CreateUpstreamRequest::builder(
        Server {
            endpoints: vec![Endpoint {
                scheme: Scheme::Http,
                host: "127.0.0.1".into(),
                port: h.mock_port(),
            }],
        },
        "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
    )
    .alias("cors-reject-method");
    builder = builder.cors(cors);

    let upstream = h
        .facade()
        .create_upstream(ctx.clone(), builder.build())
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Get, HttpMethod::Post, HttpMethod::Delete],
                        path: guard.path("/api/data"),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Disabled,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    // DELETE is allowed by the route but not by CORS — should be rejected.
    let req = http::Request::builder()
        .method(Method::DELETE)
        .uri(format!("/cors-reject-method{}", guard.path("/api/data")))
        .header("origin", "https://example.com")
        .body(Body::Empty)
        .unwrap();

    let response = h
        .facade()
        .proxy_request(h.security_context().clone(), req)
        .await;
    assert!(
        response.is_err(),
        "disallowed method on actual request should be rejected before reaching upstream"
    );
}

// CORS: Multiple specific origins — matching origin gets headers, non-matching doesn't.
#[tokio::test]
async fn cors_multiple_specific_origins() {
    let mut guard = MockGuard::new();
    guard.mock(
        "GET",
        "/api/data",
        MockResponse {
            status: 200,
            headers: vec![("content-type".into(), "application/json".into())],
            body: MockBody::Json(json!({"ok": true})),
        },
    );

    let h = AppHarness::builder().build().await;
    let cors = CorsConfig {
        allowed_origins: vec![
            "https://alpha.com".to_string(),
            "https://beta.com".to_string(),
        ],
        ..test_cors_config()
    };
    setup_cors_upstream(&h, &guard, "cors-multi", Some(cors)).await;

    // Matching origin gets CORS headers.
    let req = http::Request::builder()
        .method(Method::GET)
        .uri(format!("/cors-multi{}", guard.path("/api/data")))
        .header("origin", "https://beta.com")
        .body(Body::Empty)
        .unwrap();

    let response = h
        .facade()
        .proxy_request(h.security_context().clone(), req)
        .await
        .unwrap();
    assert_eq!(response.status(), StatusCode::OK);
    assert_eq!(
        response
            .headers()
            .get("access-control-allow-origin")
            .unwrap(),
        "https://beta.com"
    );

    // Non-matching origin is rejected before reaching upstream.
    let req = http::Request::builder()
        .method(Method::GET)
        .uri(format!("/cors-multi{}", guard.path("/api/data")))
        .header("origin", "https://gamma.com")
        .body(Body::Empty)
        .unwrap();

    let response = h
        .facade()
        .proxy_request(h.security_context().clone(), req)
        .await;
    assert!(
        response.is_err(),
        "non-matching origin should be rejected with 403"
    );
}

// ---------------------------------------------------------------------------
// WebSocket frame-aware relay integration tests
// ---------------------------------------------------------------------------

/// Read HTTP response headers from a raw TCP stream until the `\r\n\r\n` terminator.
/// Returns the complete header block as a String. Panics on timeout or if the
/// buffer fills without finding the terminator.
async fn read_http_response_headers(stream: &mut tokio::net::TcpStream) -> String {
    use tokio::io::AsyncReadExt;
    // Read one byte at a time so we never consume bytes beyond the
    // \r\n\r\n header terminator. Chunk-based reads can over-read into
    // the WebSocket frame stream, silently swallowing data and causing
    // flaky EOF errors on the first frame read.
    let mut buf = Vec::with_capacity(4096);
    let deadline = tokio::time::Instant::now() + std::time::Duration::from_secs(5);
    loop {
        let mut byte = [0u8; 1];
        tokio::time::timeout_at(deadline, stream.read_exact(&mut byte))
            .await
            .expect("timed out reading HTTP response headers")
            .expect("read error / unexpected EOF");
        buf.push(byte[0]);
        if buf.ends_with(b"\r\n\r\n") {
            return String::from_utf8_lossy(&buf).into_owned();
        }
        assert!(buf.len() < 4096, "header buffer full without \\r\\n\\r\\n");
    }
}

/// Helper: perform a WebSocket handshake over a raw TCP stream.
/// Returns the stream positioned after the 101 response headers and after
/// confirming the proxy bridge is fully operational via a Ping/Pong probe.
async fn ws_handshake(stream: &mut tokio::net::TcpStream, uri: &str) {
    use tokio::io::AsyncWriteExt;
    let req = format!(
        "GET {uri} HTTP/1.1\r\n\
         Host: 127.0.0.1\r\n\
         Upgrade: websocket\r\n\
         Connection: Upgrade\r\n\
         Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==\r\n\
         Sec-WebSocket-Version: 13\r\n\
         \r\n"
    );
    stream.write_all(req.as_bytes()).await.unwrap();
    let resp = read_http_response_headers(stream).await;
    assert!(
        resp.starts_with("HTTP/1.1 101"),
        "expected 101 Switching Protocols, got: {resp}"
    );
    // Ensure the proxy bridge is fully operational before returning.
    // Without this, the spawned bridge task may still be awaiting
    // on_upgrade when the caller sends its first data frame, causing
    // flaky "EOF on frame 0" failures under CI resource pressure.
    ws_readiness_probe(stream).await;
}

/// Helper: build a masked WebSocket frame for sending from a client.
fn build_masked_frame(opcode: u8, payload: &[u8]) -> Vec<u8> {
    let mask = [0x37, 0xfa, 0x21, 0x3d];
    let mut frame = Vec::new();
    frame.push(0x80 | opcode); // FIN + opcode
    if payload.len() < 126 {
        frame.push(0x80 | payload.len() as u8); // MASK + len
    } else {
        frame.push(0x80 | 126);
        frame.extend_from_slice(&(payload.len() as u16).to_be_bytes());
    }
    frame.extend_from_slice(&mask);
    for (i, &byte) in payload.iter().enumerate() {
        frame.push(byte ^ mask[i % 4]);
    }
    frame
}

/// Helper: read a WebSocket frame from a raw stream.
/// Returns (opcode, payload) or None on EOF or timeout.
async fn read_ws_frame(stream: &mut tokio::net::TcpStream) -> Option<(u8, Vec<u8>)> {
    use tokio::io::AsyncReadExt;
    let timeout = std::time::Duration::from_secs(5);

    let mut hdr = [0u8; 2];
    match tokio::time::timeout(timeout, stream.read_exact(&mut hdr)).await {
        Ok(Ok(_)) => {}
        _ => return None,
    }
    let opcode = hdr[0] & 0x0F;
    let masked = hdr[1] & 0x80 != 0;
    let len_byte = (hdr[1] & 0x7F) as u64;

    let payload_len: usize = if len_byte < 126 {
        len_byte as usize
    } else if len_byte == 126 {
        let mut buf = [0u8; 2];
        tokio::time::timeout(timeout, stream.read_exact(&mut buf))
            .await
            .ok()?
            .ok()?;
        u16::from_be_bytes(buf) as usize
    } else {
        let mut buf = [0u8; 8];
        tokio::time::timeout(timeout, stream.read_exact(&mut buf))
            .await
            .ok()?
            .ok()?;
        u64::from_be_bytes(buf) as usize
    };

    let mask_key = if masked {
        let mut key = [0u8; 4];
        tokio::time::timeout(timeout, stream.read_exact(&mut key))
            .await
            .ok()?
            .ok()?;
        Some(key)
    } else {
        None
    };

    let mut payload = vec![0u8; payload_len];
    if payload_len > 0 {
        tokio::time::timeout(timeout, stream.read_exact(&mut payload))
            .await
            .ok()?
            .ok()?;
    }
    if let Some(key) = mask_key {
        for (i, byte) in payload.iter_mut().enumerate() {
            *byte ^= key[i % 4];
        }
    }
    Some((opcode, payload))
}

/// Send a Ping and wait for the matching Pong, confirming the proxy bridge
/// pipeline is fully operational before the test sends data frames.
///
/// The Ping is buffered in the TCP kernel even if the bridge task hasn't
/// started reading yet — once `frame_relay` begins, it forwards the Ping
/// to the upstream, axum's tungstenite layer auto-responds with Pong, and
/// the Pong arrives back here.
async fn ws_readiness_probe(stream: &mut tokio::net::TcpStream) {
    use tokio::io::AsyncWriteExt;
    let probe = b"ready";
    let ping = build_masked_frame(0x9, probe);
    stream.write_all(&ping).await.unwrap();
    loop {
        match read_ws_frame(stream).await {
            Some((0xA, data)) if data == probe => return,
            Some((0xA, _)) => continue, // stale or unrelated Pong
            Some((0x9, _)) => continue, // Ping from upstream
            Some((0x8, close_payload)) => panic!(
                "readiness probe failed: expected Pong with payload {:?}, \
                 but server sent Close frame with payload {close_payload:?} — \
                 idle timeout may be too short for CI/coverage builds",
                std::str::from_utf8(probe).unwrap(),
            ),
            other => panic!(
                "readiness probe failed: expected Pong with payload {:?}, got {other:?}",
                std::str::from_utf8(probe).unwrap(),
            ),
        }
    }
}

/// Helper: set up an upstream + route pointing at the mock's /ws/echo endpoint.
async fn setup_ws_upstream(h: &AppHarness, alias: &str) {
    let ctx = h.security_context().clone();
    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias(alias)
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx,
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Get],
                        path: "/ws/echo".into(),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Append,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();
}

/// Helper: start an Axum server on a random port and return the address.
async fn start_oagw_server(h: &AppHarness) -> (std::net::SocketAddr, tokio::task::JoinHandle<()>) {
    let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.unwrap();
    let addr = listener.local_addr().unwrap();
    let router = h.router().clone();
    let handle = tokio::spawn(async move {
        axum::serve(listener, router).await.ok();
    });
    (addr, handle)
}

// 14.5: Close frame is forwarded through the gateway with status code preserved.
#[tokio::test(flavor = "multi_thread", worker_threads = 4)]
async fn proxy_websocket_close_frame_propagated() {
    let h = AppHarness::builder().build().await;
    setup_ws_upstream(&h, "ws-close-prop").await;
    let (addr, server_handle) = start_oagw_server(&h).await;

    let mut stream = tokio::net::TcpStream::connect(addr).await.unwrap();
    ws_handshake(&mut stream, "/oagw/v1/proxy/ws-close-prop/ws/echo").await;

    // Send a text frame to confirm the connection works.
    let text_frame = build_masked_frame(0x1, b"alive");
    tokio::io::AsyncWriteExt::write_all(&mut stream, &text_frame)
        .await
        .unwrap();
    let echo = read_ws_frame(&mut stream).await.unwrap();
    assert_eq!(echo.0, 0x1); // text opcode
    assert_eq!(echo.1, b"alive");

    // Send Close 1000 (Normal Closure).
    let mut close_payload = 1000u16.to_be_bytes().to_vec();
    close_payload.extend_from_slice(b"Normal");
    let close_frame = build_masked_frame(0x8, &close_payload);
    tokio::io::AsyncWriteExt::write_all(&mut stream, &close_frame)
        .await
        .unwrap();

    // Should receive Close frame back (echoed by mock upstream through gateway).
    // The gateway may tear down the TCP connection immediately after the close
    // handshake, so we may get the Close frame or just EOF.
    match read_ws_frame(&mut stream).await {
        Some((opcode, payload)) => {
            assert_eq!(opcode, 0x8, "expected Close opcode");
            assert!(
                payload.len() >= 2,
                "close payload should contain status code"
            );
            let code = u16::from_be_bytes([payload[0], payload[1]]);
            assert_eq!(code, 1000, "close status code should be 1000");
        }
        None => {
            // EOF after close is acceptable — the close was processed and the
            // gateway tore down the connection before we could read the response.
        }
    }

    server_handle.abort();
}

// 14.6: Idle timeout sends Close 1001 (Going Away) to the client.
#[tokio::test(flavor = "multi_thread", worker_threads = 4)]
async fn proxy_websocket_idle_timeout_sends_1001() {
    let h = AppHarness::builder()
        .with_websocket_idle_timeout(std::time::Duration::from_secs(1))
        .build()
        .await;
    setup_ws_upstream(&h, "ws-idle-1001").await;
    let (addr, server_handle) = start_oagw_server(&h).await;

    let mut stream = tokio::net::TcpStream::connect(addr).await.unwrap();
    ws_handshake(&mut stream, "/oagw/v1/proxy/ws-idle-1001/ws/echo").await;

    // Confirm connection works.
    let text_frame = build_masked_frame(0x1, b"ping");
    tokio::io::AsyncWriteExt::write_all(&mut stream, &text_frame)
        .await
        .unwrap();
    let echo = read_ws_frame(&mut stream).await.unwrap();
    assert_eq!(echo.0, 0x1);

    // Wait for idle timeout to fire.
    tokio::time::sleep(std::time::Duration::from_secs(2)).await;

    // Should receive Close 1001.
    let frame = read_ws_frame(&mut stream).await;
    match frame {
        Some((opcode, payload)) => {
            assert_eq!(opcode, 0x8, "expected Close frame after idle timeout");
            assert!(
                payload.len() >= 2,
                "close payload should contain status code"
            );
            let code = u16::from_be_bytes([payload[0], payload[1]]);
            assert_eq!(code, 1001, "idle timeout should send Close 1001 Going Away");
        }
        None => {
            // EOF is acceptable if the connection was torn down before we could read.
            // The key assertion is that the gateway closed the connection.
        }
    }

    server_handle.abort();
}

// 14.7: Max frame size enforcement sends Close 1009 (Message Too Big).
#[tokio::test(flavor = "multi_thread", worker_threads = 4)]
async fn proxy_websocket_max_frame_size_sends_1009() {
    let h = AppHarness::builder()
        .with_websocket_max_frame_size(50) // 50 bytes max
        .build()
        .await;
    setup_ws_upstream(&h, "ws-maxframe").await;
    let (addr, server_handle) = start_oagw_server(&h).await;

    let mut stream = tokio::net::TcpStream::connect(addr).await.unwrap();
    ws_handshake(&mut stream, "/oagw/v1/proxy/ws-maxframe/ws/echo").await;

    // Small frame should work fine.
    let small_frame = build_masked_frame(0x1, b"ok");
    tokio::io::AsyncWriteExt::write_all(&mut stream, &small_frame)
        .await
        .unwrap();
    let echo = read_ws_frame(&mut stream).await.unwrap();
    assert_eq!(echo.0, 0x1);
    assert_eq!(echo.1, b"ok");

    // Send a frame exceeding the 50-byte limit.
    let oversized_payload = vec![0x41; 100]; // 100 bytes > 50
    let oversized_frame = build_masked_frame(0x1, &oversized_payload);
    tokio::io::AsyncWriteExt::write_all(&mut stream, &oversized_frame)
        .await
        .unwrap();

    // Should receive Close 1009 (Message Too Big).
    // On some platforms (notably Windows) the gateway may tear down the TCP
    // connection before the Close frame is delivered, so EOF is also acceptable.
    let frame = read_ws_frame(&mut stream).await;
    match frame {
        Some((opcode, payload)) => {
            assert_eq!(opcode, 0x8, "expected Close frame for oversized message");
            assert!(
                payload.len() >= 2,
                "close payload should contain status code"
            );
            let code = u16::from_be_bytes([payload[0], payload[1]]);
            assert_eq!(code, 1009, "oversized frame should trigger Close 1009");
        }
        None => {
            // EOF / connection reset — the gateway closed the connection after
            // detecting the oversized frame, which is acceptable behaviour.
        }
    }

    server_handle.abort();
}

// 14.8: Caller disconnect mid-session triggers upstream Close.
#[tokio::test(flavor = "multi_thread", worker_threads = 4)]
async fn proxy_websocket_caller_disconnect_mid_session() {
    let h = AppHarness::builder().build().await;
    setup_ws_upstream(&h, "ws-caller-drop").await;
    let (addr, server_handle) = start_oagw_server(&h).await;

    let mut stream = tokio::net::TcpStream::connect(addr).await.unwrap();
    ws_handshake(&mut stream, "/oagw/v1/proxy/ws-caller-drop/ws/echo").await;

    // Confirm connection works.
    let text_frame = build_masked_frame(0x1, b"alive");
    tokio::io::AsyncWriteExt::write_all(&mut stream, &text_frame)
        .await
        .unwrap();
    let echo = read_ws_frame(&mut stream).await.unwrap();
    assert_eq!(echo.0, 0x1);
    assert_eq!(echo.1, b"alive");

    // Drop the client connection without sending Close — simulates abrupt disconnect.
    drop(stream);

    // Allow the gateway time to detect the disconnect and clean up.
    tokio::time::sleep(std::time::Duration::from_millis(200)).await;

    // Verify the gateway didn't crash — open a new connection and perform a
    // successful handshake on a fresh upstream to confirm the server is healthy.
    let mut stream2 = tokio::net::TcpStream::connect(addr).await.unwrap();
    ws_handshake(&mut stream2, "/oagw/v1/proxy/ws-caller-drop/ws/echo").await;
    let frame = build_masked_frame(0x1, b"still alive");
    tokio::io::AsyncWriteExt::write_all(&mut stream2, &frame)
        .await
        .unwrap();
    let echo = read_ws_frame(&mut stream2).await.unwrap();
    assert_eq!(echo.0, 0x1);
    assert_eq!(echo.1, b"still alive");

    server_handle.abort();
}

// 14.9: Connection header with multiple upgrade tokens (e.g. "keep-alive, Upgrade")
// is handled correctly — the WebSocket upgrade is still detected and processed.
#[tokio::test(flavor = "multi_thread", worker_threads = 4)]
async fn proxy_websocket_connection_header_multi_value() {
    let h = AppHarness::builder().build().await;
    setup_ws_upstream(&h, "ws-multi-conn").await;
    let (addr, server_handle) = start_oagw_server(&h).await;

    let mut stream = tokio::net::TcpStream::connect(addr).await.unwrap();

    // Send handshake with multi-value Connection header: "keep-alive, Upgrade".
    use tokio::io::AsyncWriteExt;
    let req = "GET /oagw/v1/proxy/ws-multi-conn/ws/echo HTTP/1.1\r\n\
         Host: 127.0.0.1\r\n\
         Upgrade: websocket\r\n\
         Connection: keep-alive, Upgrade\r\n\
         Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==\r\n\
         Sec-WebSocket-Version: 13\r\n\
         \r\n"
        .to_string();
    stream.write_all(req.as_bytes()).await.unwrap();
    let resp = read_http_response_headers(&mut stream).await;
    assert!(
        resp.starts_with("HTTP/1.1 101"),
        "expected 101 with multi-value Connection header, got: {resp}"
    );

    // Confirm the connection works — send a text frame and receive echo.
    let text_frame = build_masked_frame(0x1, b"multi-conn");
    stream.write_all(&text_frame).await.unwrap();
    let echo = read_ws_frame(&mut stream).await.unwrap();
    assert_eq!(echo.0, 0x1);
    assert_eq!(echo.1, b"multi-conn");

    server_handle.abort();
}

// 14.10: Ping/Pong frames forwarded through the gateway end-to-end.
#[tokio::test(flavor = "multi_thread", worker_threads = 4)]
async fn proxy_websocket_ping_pong_forwarded() {
    let h = AppHarness::builder().build().await;
    setup_ws_upstream(&h, "ws-pingpong").await;
    let (addr, server_handle) = start_oagw_server(&h).await;

    let mut stream = tokio::net::TcpStream::connect(addr).await.unwrap();
    ws_handshake(&mut stream, "/oagw/v1/proxy/ws-pingpong/ws/echo").await;

    // Send a Ping frame (opcode 0x9). The echo mock may or may not reply
    // with a Pong, but the key assertion is that the frame reaches the
    // upstream without crashing the gateway.
    let ping_frame = build_masked_frame(0x9, b"ping");
    tokio::io::AsyncWriteExt::write_all(&mut stream, &ping_frame)
        .await
        .unwrap();

    // After Ping, verify the connection is still functional by sending a
    // text message and checking the echo.
    let text_frame = build_masked_frame(0x1, b"after-ping");
    tokio::io::AsyncWriteExt::write_all(&mut stream, &text_frame)
        .await
        .unwrap();

    // Read frames until we get the text echo (may have a Pong in between).
    loop {
        let frame = read_ws_frame(&mut stream).await;
        match frame {
            Some((0x1, data)) => {
                assert_eq!(data, b"after-ping");
                break;
            }
            Some((0xA, _)) => continue, // Pong — skip
            Some((0x9, _)) => continue, // Ping from upstream — skip
            other => panic!("unexpected frame: {other:?}"),
        }
    }

    server_handle.abort();
}

// 14.11: Binary frames preserve opcode through the gateway end-to-end.
#[tokio::test(flavor = "multi_thread", worker_threads = 4)]
async fn proxy_websocket_binary_frame_opcode_preserved() {
    let h = AppHarness::builder().build().await;
    setup_ws_upstream(&h, "ws-binary-op").await;
    let (addr, server_handle) = start_oagw_server(&h).await;

    let mut stream = tokio::net::TcpStream::connect(addr).await.unwrap();
    ws_handshake(&mut stream, "/oagw/v1/proxy/ws-binary-op/ws/echo").await;

    // Send a binary frame (opcode 0x2).
    let payload: Vec<u8> = (0..=255).collect();
    let binary_frame = build_masked_frame(0x2, &payload);
    tokio::io::AsyncWriteExt::write_all(&mut stream, &binary_frame)
        .await
        .unwrap();

    // Echo should come back as binary (opcode 0x2), not text.
    let echo = read_ws_frame(&mut stream).await.unwrap();
    assert_eq!(
        echo.0, 0x2,
        "expected binary opcode 0x2, got 0x{:x}",
        echo.0
    );
    assert_eq!(echo.1, payload);

    server_handle.abort();
}

// 14.12: Sustained multi-message session with extended-length payloads.
// Sends 60 frames of varying sizes (including 2-byte and 8-byte extended length
// encodings) through the full Axum→Pingora→mock→relay→client stack, exercising
// the relay loop's long-running behavior.
#[tokio::test(flavor = "multi_thread", worker_threads = 4)]
async fn proxy_websocket_sustained_multi_message_extended_lengths() {
    let h = AppHarness::builder().build().await;
    setup_ws_upstream(&h, "ws-sustained").await;
    let (addr, server_handle) = start_oagw_server(&h).await;

    let mut stream = tokio::net::TcpStream::connect(addr).await.unwrap();
    ws_handshake(&mut stream, "/oagw/v1/proxy/ws-sustained/ws/echo").await;

    // Mix of payload sizes:
    // - tiny (< 126 bytes, 1-byte length encoding)
    // - medium (200–499 bytes, 2-byte extended length encoding)
    // - large (30 KiB, 2-byte extended length — comfortably within the
    //   65 KiB DuplexStream bridge buffer; 8-byte encoding is covered by
    //   unit tests in websocket.rs::extended_length_payloads)
    let sizes: Vec<usize> = (0..60)
        .map(|i| match i % 3 {
            0 => 10 + (i * 7) % 100,   // tiny: 10–109 bytes
            1 => 200 + (i * 13) % 300, // medium: 200–499 bytes
            _ => 30_000,               // large: 30 KiB
        })
        .collect();

    for (i, &size) in sizes.iter().enumerate() {
        // Alternate text and binary to exercise opcode preservation.
        // Text frames must contain valid UTF-8 (the mock's axum WebSocket
        // validates this), so use ASCII-printable chars for text and raw
        // bytes for binary.
        let opcode = if i % 2 == 0 { 0x1 } else { 0x2 };
        let payload: Vec<u8> = if opcode == 0x1 {
            // Valid ASCII text: cycle through printable chars (0x20–0x7E).
            (0..size).map(|j| (0x20 + ((i + j) % 95)) as u8).collect()
        } else {
            // Raw binary: full byte range.
            (0..size).map(|j| ((i + j) % 256) as u8).collect()
        };
        let frame = build_masked_frame(opcode, &payload);
        tokio::io::AsyncWriteExt::write_all(&mut stream, &frame)
            .await
            .unwrap();

        let echo = tokio::time::timeout(
            std::time::Duration::from_secs(10),
            read_ws_frame(&mut stream),
        )
        .await
        .unwrap_or_else(|_| panic!("timeout waiting for echo of frame {i} (size {size})"));
        let (echo_op, echo_data) = echo.unwrap_or_else(|| panic!("EOF on frame {i}"));

        assert_eq!(
            echo_op, opcode,
            "frame {i}: opcode mismatch (expected 0x{opcode:x}, got 0x{echo_op:x})"
        );
        assert_eq!(echo_data.len(), size, "frame {i}: payload length mismatch");
        assert_eq!(
            echo_data, payload,
            "frame {i}: payload content mismatch (size {size})"
        );
    }

    server_handle.abort();
}

// 14.13: JSON-structured payload with multi-byte UTF-8 survives the proxy.
// Sends a realistic JSON message containing emoji, CJK, combining characters,
// and 4-byte UTF-8 sequences to verify the frame relay doesn't corrupt
// multi-byte boundaries.
#[tokio::test(flavor = "multi_thread", worker_threads = 4)]
async fn proxy_websocket_json_utf8_payload_integrity() {
    let h = AppHarness::builder().build().await;
    setup_ws_upstream(&h, "ws-json-utf8").await;
    let (addr, server_handle) = start_oagw_server(&h).await;

    let mut stream = tokio::net::TcpStream::connect(addr).await.unwrap();
    ws_handshake(&mut stream, "/oagw/v1/proxy/ws-json-utf8/ws/echo").await;

    // Realistic JSON payloads with multi-byte UTF-8.
    let payloads = [
        // OpenAI Realtime-style event with emoji and CJK
        r#"{"type":"response.audio_transcript.delta","event_id":"evt_001","delta":"こんにちは世界 🌍🔥 café résumé naïve"}"#,
        // 4-byte UTF-8: Mathematical Bold Script (U+1D4D0–U+1D503) and emoji
        r#"{"message":"𝓗𝓮𝓵𝓵𝓸 from 𝕋𝕖𝕤𝕥","emoji":"👨‍👩‍👧‍👦🏳️‍🌈","nulls":null,"nested":{"flag":true}}"#,
        // Combining characters and zero-width joiners
        r#"{"text":"e\u0301 n\u0303 o\u0308","zwj":"👩\u200d🔬","count":42}"#,
        // Large realistic message: chat completion chunk with mixed scripts
        r#"{"id":"chatcmpl-abc123","object":"chat.completion.chunk","created":1700000000,"model":"gpt-4","choices":[{"index":0,"delta":{"content":"Привет мир • مرحبا بالعالم • 你好世界"},"finish_reason":null}]}"#,
    ];

    for (i, payload_str) in payloads.iter().enumerate() {
        let payload = payload_str.as_bytes();
        let frame = build_masked_frame(0x1, payload);
        tokio::io::AsyncWriteExt::write_all(&mut stream, &frame)
            .await
            .unwrap();

        let echo = read_ws_frame(&mut stream)
            .await
            .unwrap_or_else(|| panic!("EOF on JSON payload {i}"));
        assert_eq!(echo.0, 0x1, "payload {i}: expected text opcode");
        assert_eq!(
            echo.1, payload,
            "payload {i}: byte-level mismatch — UTF-8 corruption through proxy"
        );

        // Also validate that the echoed bytes are valid UTF-8 and round-trip
        // through serde_json without loss.
        let echoed_str = std::str::from_utf8(&echo.1).expect("echoed payload is not valid UTF-8");
        let parsed: serde_json::Value =
            serde_json::from_str(echoed_str).expect("echoed payload is not valid JSON");
        let original: serde_json::Value =
            serde_json::from_str(payload_str).expect("original payload is not valid JSON");
        assert_eq!(
            parsed, original,
            "payload {i}: JSON semantic mismatch after proxy round-trip"
        );
    }

    server_handle.abort();
}

// Response header rules: set/add/remove operations applied to upstream response.
#[tokio::test]
async fn proxy_response_header_rules_applied() {
    let h = AppHarness::builder().build().await;
    let ctx = h.security_context().clone();

    let upstream = h
        .facade()
        .create_upstream(
            ctx.clone(),
            CreateUpstreamRequest::builder(
                Server {
                    endpoints: vec![Endpoint {
                        scheme: Scheme::Http,
                        host: "127.0.0.1".into(),
                        port: h.mock_port(),
                    }],
                },
                "gts.x.core.oagw.protocol.v1~x.core.oagw.http.v1",
            )
            .alias("resp-rules-test")
            .headers(HeadersConfig {
                request: None,
                response: Some(ResponseHeaderRules {
                    set: [("x-custom-safe".into(), "overwritten".into())]
                        .into_iter()
                        .collect(),
                    add: [("x-injected".into(), "added-value".into())]
                        .into_iter()
                        .collect(),
                    remove: vec!["x-remove-target".into()],
                }),
            })
            .build(),
        )
        .await
        .unwrap();

    h.facade()
        .create_route(
            ctx.clone(),
            CreateRouteRequest::builder(
                upstream.id,
                MatchRules {
                    http: Some(HttpMatch {
                        methods: vec![HttpMethod::Get],
                        path: "/response-headers".into(),
                        query_allowlist: vec![],
                        path_suffix_mode: PathSuffixMode::Append,
                    }),
                    grpc: None,
                },
            )
            .build(),
        )
        .await
        .unwrap();

    let req = http::Request::builder()
        .method(Method::GET)
        .uri("/resp-rules-test/response-headers")
        .body(Body::Empty)
        .unwrap();
    let response = h.facade().proxy_request(ctx.clone(), req).await.unwrap();
    assert_eq!(response.status(), StatusCode::OK);

    let headers = response.headers();

    // "set" overwrites existing header from upstream mock.
    assert_eq!(
        headers.get("x-custom-safe").unwrap(),
        "overwritten",
        "response set rule should overwrite upstream header"
    );

    // "add" injects a new header.
    assert_eq!(
        headers.get("x-injected").unwrap(),
        "added-value",
        "response add rule should inject header"
    );
}
