use std::collections::BTreeMap;

use axum::{
    Json, Router,
    extract::{Path, Query},
    http::{HeaderMap, StatusCode},
    response::Redirect,
    routing::{get, post},
};
use crank_adapter_rest::{OutboundHttpPolicy, RestAdapter, RestAdapterError, RestRequest};
use crank_core::{
    HttpMethod, PreparedRequest, ProtocolAdapter, RestTarget, RuntimeRequestContext, Target,
};
use opentelemetry::{
    global,
    trace::{TraceContextExt, TracerProvider as _},
};
use opentelemetry_sdk::{propagation::TraceContextPropagator, trace::SdkTracerProvider};
use serde_json::{Value, json};
use tokio::net::TcpListener;
use tracing::Instrument;
use tracing_opentelemetry::OpenTelemetrySpanExt;
use tracing_subscriber::layer::SubscriberExt;

#[tokio::test]
async fn executes_rest_request_and_normalizes_json_response() {
    let base_url = spawn_test_server().await;
    let adapter = test_adapter();
    let target = RestTarget {
        base_url,
        method: HttpMethod::Post,
        path_template: "/users/{user_id}".to_owned(),
        static_headers: BTreeMap::from([("x-static".to_owned(), "static".to_owned())]),
    };
    let request = RestRequest {
        path_params: BTreeMap::from([("user_id".to_owned(), "42".to_owned())]),
        query_params: BTreeMap::from([("expand".to_owned(), "true".to_owned())]),
        headers: BTreeMap::from([("x-trace-id".to_owned(), "trace-123".to_owned())]),
        body: Some(json!({ "name": "Ada" })),
        timeout_ms: 1_000,
    };

    let response = adapter.execute(&target, &request).await.unwrap();

    assert_eq!(response.status_code, 200);
    assert_eq!(
        response.body,
        json!({
            "id": "42",
            "query": "true",
            "trace": "trace-123",
            "static": "static",
            "payload": { "name": "Ada" }
        })
    );
}

#[tokio::test]
async fn protocol_context_overrides_mapped_correlation_headers() {
    let base_url = spawn_test_server().await;
    let adapter = test_adapter();
    let target = Target::Rest(RestTarget {
        base_url,
        method: HttpMethod::Post,
        path_template: "/users/{user_id}".to_owned(),
        static_headers: BTreeMap::from([
            ("x-request-id".to_owned(), "static-request".to_owned()),
            (
                "x-correlation-id".to_owned(),
                "static-correlation".to_owned(),
            ),
        ]),
    });
    let prepared = PreparedRequest {
        path_params: BTreeMap::from([("user_id".to_owned(), "42".to_owned())]),
        headers: BTreeMap::from([
            ("x-request-id".to_owned(), "mapped-request".to_owned()),
            (
                "x-correlation-id".to_owned(),
                "mapped-correlation".to_owned(),
            ),
        ]),
        body: Some(json!({ "name": "Ada" })),
        timeout_ms: 1_000,
        ..PreparedRequest::default()
    };
    let context = RuntimeRequestContext::new("req-runtime", "corr-runtime");

    let response = adapter
        .invoke_unary(&target, &prepared, &context)
        .await
        .unwrap();

    assert_eq!(response.body["request_id"], "req-runtime");
    assert_eq!(response.body["correlation_id"], "corr-runtime");
}

#[tokio::test(flavor = "current_thread")]
async fn current_trace_context_overrides_mapped_traceparent() {
    global::set_text_map_propagator(TraceContextPropagator::new());
    let provider = SdkTracerProvider::builder().build();
    let tracer = provider.tracer("rest-propagation-test");
    let subscriber =
        tracing_subscriber::registry().with(tracing_opentelemetry::layer().with_tracer(tracer));
    let dispatch = tracing::Dispatch::new(subscriber);
    let _dispatch_guard = tracing::dispatcher::set_default(&dispatch);
    let span = tracing::info_span!("runtime.execute");
    let context = span.context();
    let expected_trace_id = context.span().span_context().trace_id().to_string();
    let base_url = spawn_test_server().await;
    let target = RestTarget {
        base_url,
        method: HttpMethod::Post,
        path_template: "/users/{user_id}".to_owned(),
        static_headers: BTreeMap::new(),
    };
    let request = RestRequest {
        path_params: BTreeMap::from([("user_id".to_owned(), "42".to_owned())]),
        query_params: BTreeMap::new(),
        headers: BTreeMap::from([(
            "traceparent".to_owned(),
            "00-11111111111111111111111111111111-2222222222222222-01".to_owned(),
        )]),
        body: Some(json!({ "name": "Ada" })),
        timeout_ms: 1_000,
    };

    let response = test_adapter()
        .execute(&target, &request)
        .instrument(span)
        .await
        .unwrap();

    assert_eq!(
        &response.body["traceparent"].as_str().unwrap()[3..35],
        expected_trace_id
    );
    provider.shutdown().unwrap();
}

#[tokio::test]
async fn user_configured_propagation_headers_are_removed_without_trusted_context() {
    let base_url = spawn_test_server().await;
    let target = RestTarget {
        base_url,
        method: HttpMethod::Post,
        path_template: "/users/{user_id}".to_owned(),
        static_headers: BTreeMap::from([
            (
                "traceparent".to_owned(),
                "untrusted\ninvalid-value".to_owned(),
            ),
            ("tracestate".to_owned(), "vendor=value".to_owned()),
            ("baggage".to_owned(), "secret=must-not-leave".to_owned()),
        ]),
    };
    let request = RestRequest {
        path_params: BTreeMap::from([("user_id".to_owned(), "42".to_owned())]),
        query_params: BTreeMap::new(),
        headers: BTreeMap::new(),
        body: Some(json!({ "name": "Ada" })),
        timeout_ms: 1_000,
    };

    let response = test_adapter().execute(&target, &request).await.unwrap();

    assert!(response.body.get("traceparent").is_none());
    assert!(response.body.get("tracestate").is_none());
    assert!(response.body.get("baggage").is_none());
}

#[tokio::test]
async fn returns_unexpected_status_with_normalized_body() {
    let base_url = spawn_test_server().await;
    let adapter = test_adapter();
    let target = RestTarget {
        base_url,
        method: HttpMethod::Get,
        path_template: "/fail".to_owned(),
        static_headers: BTreeMap::new(),
    };
    let request = RestRequest {
        path_params: BTreeMap::new(),
        query_params: BTreeMap::new(),
        headers: BTreeMap::new(),
        body: None,
        timeout_ms: 1_000,
    };

    let error = adapter.execute(&target, &request).await.unwrap_err();

    assert!(matches!(
        error,
        RestAdapterError::UnexpectedStatus {
            status: 502,
            body: Value::Object(_)
        }
    ));
}

#[test]
fn rejects_private_targets_by_default() {
    let policy = OutboundHttpPolicy::default();

    let error = policy
        .validate_base_url("http://127.0.0.1:8080")
        .unwrap_err();

    assert!(matches!(error, RestAdapterError::TargetNotAllowed { .. }));
}

#[test]
fn accepts_explicit_private_ipv4_and_ipv6_targets() {
    let policy = OutboundHttpPolicy::allowing_hosts(["192.168.1.10", "::1"]);

    assert!(policy.validate_base_url("http://192.168.1.10:8080").is_ok());
    assert!(policy.validate_base_url("http://[::1]:8080").is_ok());
}

#[tokio::test]
async fn does_not_follow_redirects() {
    let base_url = spawn_test_server().await;
    let adapter = test_adapter();
    let target = RestTarget {
        base_url,
        method: HttpMethod::Get,
        path_template: "/redirect".to_owned(),
        static_headers: BTreeMap::new(),
    };

    let error = adapter
        .execute(&target, &empty_request())
        .await
        .unwrap_err();

    assert!(matches!(
        error,
        RestAdapterError::UnexpectedStatus { status: 303, .. }
    ));
}

#[tokio::test]
async fn rejects_responses_over_the_configured_limit() {
    let base_url = spawn_test_server().await;
    let adapter = RestAdapter::with_policy(
        OutboundHttpPolicy::allowing_hosts(["127.0.0.1"]).with_max_response_bytes(8),
    );
    let target = RestTarget {
        base_url,
        method: HttpMethod::Get,
        path_template: "/large".to_owned(),
        static_headers: BTreeMap::new(),
    };

    let error = adapter
        .execute(&target, &empty_request())
        .await
        .unwrap_err();

    assert!(matches!(
        error,
        RestAdapterError::ResponseTooLarge { limit_bytes: 8 }
    ));
}

fn empty_request() -> RestRequest {
    RestRequest {
        path_params: BTreeMap::new(),
        query_params: BTreeMap::new(),
        headers: BTreeMap::new(),
        body: None,
        timeout_ms: 1_000,
    }
}

fn test_adapter() -> RestAdapter {
    RestAdapter::with_policy(OutboundHttpPolicy::allowing_hosts(["127.0.0.1"]))
}

async fn spawn_test_server() -> String {
    let app = Router::new()
        .route("/users/{user_id}", post(create_user))
        .route("/fail", get(fail))
        .route("/redirect", get(|| async { Redirect::to("/large") }))
        .route(
            "/large",
            get(|| async { "response larger than eight bytes" }),
        );
    let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
    let address = listener.local_addr().unwrap();

    tokio::spawn(async move {
        axum::serve(listener, app).await.unwrap();
    });

    format!("http://{}", address)
}

async fn create_user(
    Path(user_id): Path<String>,
    Query(query): Query<BTreeMap<String, String>>,
    headers: HeaderMap,
    Json(payload): Json<Value>,
) -> Json<Value> {
    let trace = headers
        .get("x-trace-id")
        .and_then(|value| value.to_str().ok())
        .unwrap_or_default();
    let static_header = headers
        .get("x-static")
        .and_then(|value| value.to_str().ok())
        .unwrap_or_default();
    let request_id = headers
        .get("x-request-id")
        .and_then(|value| value.to_str().ok());
    let correlation_id = headers
        .get("x-correlation-id")
        .and_then(|value| value.to_str().ok());
    let traceparent = headers
        .get("traceparent")
        .and_then(|value| value.to_str().ok());
    let tracestate = headers
        .get("tracestate")
        .and_then(|value| value.to_str().ok());
    let baggage = headers.get("baggage").and_then(|value| value.to_str().ok());

    let mut response = json!({
        "id": user_id,
        "query": query.get("expand").cloned().unwrap_or_default(),
        "trace": trace,
        "static": static_header,
        "payload": payload
    });
    let response = response.as_object_mut().unwrap();
    if let Some(request_id) = request_id {
        response.insert(
            "request_id".to_owned(),
            Value::String(request_id.to_owned()),
        );
    }
    if let Some(correlation_id) = correlation_id {
        response.insert(
            "correlation_id".to_owned(),
            Value::String(correlation_id.to_owned()),
        );
    }
    if let Some(traceparent) = traceparent {
        response.insert(
            "traceparent".to_owned(),
            Value::String(traceparent.to_owned()),
        );
    }
    if let Some(tracestate) = tracestate {
        response.insert(
            "tracestate".to_owned(),
            Value::String(tracestate.to_owned()),
        );
    }
    if let Some(baggage) = baggage {
        response.insert("baggage".to_owned(), Value::String(baggage.to_owned()));
    }

    Json(Value::Object(response.clone()))
}

async fn fail() -> (axum::http::StatusCode, Json<Value>) {
    (
        StatusCode::BAD_GATEWAY,
        Json(json!({ "error": "upstream failed" })),
    )
}