//! The swarm UI's PR report: every open pull request of the forge, or of one
//! repo, with the attributes a reviewer or merger filters on already
//! resolved. The logic is [`forge::Client::pr_report`]; this module is the
//! HTTP surface over it, the same shape as [`crate::issue_report`]. The repo
//! dropdown's source is `GET /api/pulls/repos`.

use axum::{
    Json,
    extract::{Path, State},
};

use crate::forge;
use crate::issue_report::issue_report_error_status;
use crate::routes::{AppState, error_problem};

/// The 503 detail when the forge did not answer within
/// [`forge::FORGE_DEADLINE`].
const DEADLINE_DETAIL: &str = "the forge did not answer within the deadline";

/// Every open pull request across every repo that has one.
#[utoipa::path(
    get,
    path = "/api/pr-report",
    responses(
        (status = 200, description = "every open pull request, newest number first within a repo", body = Vec<forge::pr_report::PrReportRow>),
        (status = 503, description = "no forge is configured on this host, the report could not be built, or the forge did not answer within two minutes (problem+json)", body = String),
    ),
    tag = "pulls"
)]
pub async fn get_pr_report_all(
    State(state): State<AppState>,
) -> Result<Json<Vec<forge::pr_report::PrReportRow>>, problem_details::ProblemDetails> {
    let Some(client) = state.forge.get() else {
        return Err(error_problem(
            axum::http::StatusCode::SERVICE_UNAVAILABLE,
            "no forge is configured on this host",
        ));
    };
    let Some(built) = forge::within_forge_deadline("PR report", client.pr_report_all()).await
    else {
        return Err(error_problem(
            axum::http::StatusCode::SERVICE_UNAVAILABLE,
            DEADLINE_DETAIL,
        ));
    };
    match built {
        Ok(rows) => Ok(Json(rows)),
        Err(e) => {
            let detail = format!("{e:#}");
            tracing::warn!(error = %detail, "building the all-repos PR report failed");
            Err(error_problem(
                axum::http::StatusCode::SERVICE_UNAVAILABLE,
                &detail,
            ))
        }
    }
}

/// The open pull requests of `{org}/{repo}`. A 404 from the forge for the
/// repo itself is a 404 here; anything else stays 503, as for the issue
/// report ([`issue_report_error_status`]).
#[utoipa::path(
    get,
    path = "/api/repos/{org}/{repo}/pr-report",
    params(
        ("org" = String, Path, description = "repo owner (user or org)"),
        ("repo" = String, Path, description = "repo name"),
    ),
    responses(
        (status = 200, description = "every open pull request in this repo", body = Vec<forge::pr_report::PrReportRow>),
        (status = 404, description = "no such repo (problem+json)", body = String),
        (status = 503, description = "no forge is configured on this host, the report could not be built, or the forge did not answer within two minutes (problem+json)", body = String),
    ),
    tag = "pulls"
)]
pub async fn get_pr_report(
    State(state): State<AppState>,
    Path((org, repo)): Path<(String, String)>,
) -> Result<Json<Vec<forge::pr_report::PrReportRow>>, problem_details::ProblemDetails> {
    let Some(client) = state.forge.get() else {
        return Err(error_problem(
            axum::http::StatusCode::SERVICE_UNAVAILABLE,
            "no forge is configured on this host",
        ));
    };
    let Some(built) =
        forge::within_forge_deadline("repo PR report", client.pr_report(&org, &repo)).await
    else {
        return Err(error_problem(
            axum::http::StatusCode::SERVICE_UNAVAILABLE,
            DEADLINE_DETAIL,
        ));
    };
    match built {
        Ok(rows) => Ok(Json(rows)),
        Err(e) => {
            let status = issue_report_error_status(&e);
            if status == axum::http::StatusCode::NOT_FOUND {
                Err(error_problem(status, &format!("{org}/{repo} not found")))
            } else {
                let detail = format!("{e:#}");
                tracing::warn!(error = %detail, %org, %repo, "building PR report failed");
                Err(error_problem(status, &detail))
            }
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    /// Each route against a forge that accepts the connection and never
    /// answers: 503 at the deadline. The paused clock jumps to the deadline
    /// once nothing else can run, so this takes no wall time.
    #[tokio::test(start_paused = true)]
    async fn every_route_is_503_when_the_forge_never_answers() {
        use axum::body::Body;
        use axum::http::{Request, StatusCode};
        use tower::ServiceExt as _;

        let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.unwrap();
        let url = url::Url::parse(&format!("http://{}/", listener.local_addr().unwrap())).unwrap();
        for uri in ["/api/pr-report", "/api/repos/o/r/pr-report"] {
            let (state, _) = crate::routes::tests::state_with_roster();
            assert!(
                state
                    .forge
                    .set(std::sync::Arc::new(forge::Client::for_test_forge(
                        url.clone()
                    )))
                    .is_ok()
            );
            let start = tokio::time::Instant::now();
            let req = Request::get(uri).body(Body::empty()).expect("a request");
            let res = crate::startup::build_app(state)
                .oneshot(req)
                .await
                .expect("infallible");
            assert_eq!(res.status(), StatusCode::SERVICE_UNAVAILABLE, "{uri}");
            let bytes = axum::body::to_bytes(res.into_body(), usize::MAX)
                .await
                .unwrap();
            let body = String::from_utf8_lossy(&bytes);
            assert!(body.contains(super::DEADLINE_DETAIL), "{uri}: {body}");
            assert_eq!(start.elapsed(), forge::FORGE_DEADLINE, "{uri}");
        }
    }
}