use opentelemetry::global;
use opentelemetry_http::HeaderInjector;
use tracing::{Instrument as _, Span};
use tracing_opentelemetry::OpenTelemetrySpanExt;

/// Client span for an outbound HTTP call; the trace context of this span is
/// what gets injected into the request, so the remote hop parents to it.
pub fn http_client_span(method: &str, url: &str) -> Span {
    let name = format!("{method} {url}");
    tracing::info_span!(
        "http.client",
        "otel.name" = %name,
        "otel.kind" = "client",
        "http.request.method" = %method,
        "url.full" = %url,
        "http.response.status_code" = tracing::field::Empty,
    )
}

/// Sends a request inside `span` with `traceparent` injected into its headers.
pub async fn send(
    span: Span,
    request: reqwest::RequestBuilder,
) -> Result<reqwest::Response, reqwest::Error> {
    let mut headers = http::HeaderMap::new();
    global::get_text_map_propagator(|propagator| {
        propagator.inject_context(&span.context(), &mut HeaderInjector(&mut headers));
    });
    if let Some(request_id) = envelope::context::request_id()
        && let Ok(value) = request_id.parse()
    {
        headers.insert(
            http::header::HeaderName::from_static(envelope::REQUEST_ID_HEADER),
            value,
        );
    }

    let result = request
        .headers(headers)
        .send()
        .instrument(span.clone())
        .await;
    match &result {
        Ok(response) => {
            span.record(
                "http.response.status_code",
                i64::from(response.status().as_u16()),
            );
        }
        Err(_) => {
            span.record("otel.status_code", "error");
        }
    }
    result
}