//! arr-api — the HTTP surface. See DESIGN.md §9.1.
//!
//! The API is the product; the web UI is one client of it. So the `OpenAPI`
//! document is not written by hand and not kept in step by review: routes are
//! registered through [`utoipa_axum::routes`], which only accepts a handler
//! carrying a `#[utoipa::path]` annotation. A handler added without one fails
//! to compile, and the gate in DESIGN.md §12 fails with it.

mod health;
mod movies;
mod owners;
mod roots;
mod search;
mod state;

use axum::routing::get;
use axum::{Json, Router};
use utoipa::OpenApi;
use utoipa_axum::router::OpenApiRouter;
use utoipa_axum::routes;
use utoipa_scalar::{Scalar, Servable};

pub use health::{Check, Health, HealthReport, Status};
pub use movies::{Accepted, AttentionQueues, CreateMovie, ErrorBody, Movie, Release, UpdateMovie};
pub use owners::{CreateOwner, Owner, UpdateOwner};
pub use roots::Root;
pub use search::{ClassifiedRelease, SearchResponse};
pub use state::{AppState, MovieCommand, Upstreams, DEFAULT_TMDB_URL};

/// Where the generated document is served, and where `just gen-client` reads
/// it back from when it is fetched rather than dumped from the binary.
pub const OPENAPI_PATH: &str = "/api/openapi.json";

/// Where the browsable UI lives.
pub const DOCS_PATH: &str = "/api/docs";

/// Document-level metadata. Paths and schemas are collected from the router,
/// never listed here — a list is a thing to forget to update.
#[derive(OpenApi)]
#[openapi(
    info(
        title = "arr",
        description = "One service in place of Radarr and Sonarr. No authentication: \
                       the perimeter is the VPN (DESIGN.md §2).",
    ),
    tags(
        (name = "system", description = "Service health and metadata"),
        (name = "movies", description = "Movie library and actions"),
        (name = "owners", description = "Owner tags and filtered views (DESIGN.md §4.3)"),
        (name = "search", description = "Unified title and release search"),
        (name = "roots", description = "Root folders and their policies")
    ),
)]
struct ApiDoc;

/// Every annotated route, still needing state.
fn api_router() -> OpenApiRouter<AppState> {
    OpenApiRouter::with_openapi(ApiDoc::openapi())
        .routes(routes!(health::health))
        .routes(routes!(movies::list, movies::create))
        .routes(routes!(movies::get, movies::update, movies::delete))
        .routes(routes!(movies::search))
        .routes(routes!(movies::releases))
        .routes(routes!(movies::grab))
        .routes(routes!(movies::attention))
        .routes(routes!(movies::list_owners))
        .routes(routes!(movies::tag_owner, movies::untag_owner))
        .routes(routes!(owners::list, owners::create))
        .routes(routes!(owners::get, owners::update, owners::delete))
        .routes(routes!(search::search))
        .routes(routes!(search::releases))
        .routes(routes!(roots::list))
}

/// The generated `OpenAPI` document.
#[must_use]
pub fn openapi() -> utoipa::openapi::OpenApi {
    api_router().split_for_parts().1
}

/// The whole application: the API, the served document, and the browsable UI.
pub fn router(state: AppState) -> Router {
    let (router, api) = api_router().split_for_parts();
    let document = api.clone();

    router
        .route(
            OPENAPI_PATH,
            get(move || {
                let document = document.clone();
                async move { Json(document) }
            }),
        )
        .merge(Scalar::with_url(DOCS_PATH, api))
        .with_state(state)
}

#[cfg(test)]
mod tests {
    use super::*;
    use wiremock::matchers::{method, path};
    use wiremock::{Mock, MockServer, ResponseTemplate};

    /// A Prowlarr that answers `/ping`, and a Transmission that answers an
    /// RPC call the way a real one does when it has no session id yet.
    async fn upstreams_up() -> (MockServer, MockServer) {
        let prowlarr = MockServer::start().await;
        Mock::given(method("GET"))
            .and(path("/ping"))
            .respond_with(
                ResponseTemplate::new(200).set_body_json(serde_json::json!({ "status": "OK" })),
            )
            .mount(&prowlarr)
            .await;

        let transmission = MockServer::start().await;
        Mock::given(method("POST"))
            .and(path("/transmission/rpc"))
            .respond_with(
                ResponseTemplate::new(409).insert_header("X-Transmission-Session-Id", "abc"),
            )
            .mount(&transmission)
            .await;

        (prowlarr, transmission)
    }

    /// Serve the app on an ephemeral port and return its base URL. The server
    /// task dies with the runtime at the end of the test.
    async fn serve(state: AppState) -> String {
        let listener = tokio::net::TcpListener::bind("127.0.0.1:0")
            .await
            .expect("bind ephemeral port");
        let addr = listener.local_addr().expect("local addr");
        tokio::spawn(async move {
            axum::serve(listener, router(state)).await.expect("serve");
        });
        format!("http://{addr}")
    }

    async fn report(state: AppState) -> serde_json::Value {
        let base = serve(state).await;
        let response = reqwest::get(format!("{base}/api/health"))
            .await
            .expect("request health");
        assert_eq!(response.status(), 200, "health always answers 200");
        response.json().await.expect("health body is json")
    }

    #[tokio::test]
    async fn all_upstreams_up_is_ok() {
        let (prowlarr, transmission) = upstreams_up().await;
        let tmdb = MockServer::start().await;
        Mock::given(method("GET"))
            .and(path("/configuration"))
            .respond_with(ResponseTemplate::new(200).set_body_json(serde_json::json!({})))
            .mount(&tmdb)
            .await;

        let state = AppState::new(
            Upstreams::new(
                prowlarr.uri(),
                format!("{}/transmission/rpc", transmission.uri()),
            )
            .with_tmdb_url(tmdb.uri())
            .with_tmdb_api_key(Some("key".into())),
        )
        .expect("state");

        let body = report(state).await;
        assert_eq!(body["status"], "ok");
        assert_eq!(body["prowlarr"]["status"], "ok");
        assert_eq!(body["transmission"]["status"], "ok");
        assert_eq!(body["tmdb"]["status"], "ok");
        assert_eq!(body["version"], env!("CARGO_PKG_VERSION"));
    }

    #[tokio::test]
    async fn a_missing_tmdb_key_is_unconfigured_not_an_outage() {
        let (prowlarr, transmission) = upstreams_up().await;
        let state = AppState::new(Upstreams::new(
            prowlarr.uri(),
            format!("{}/transmission/rpc", transmission.uri()),
        ))
        .expect("state");

        let body = report(state).await;
        assert_eq!(body["tmdb"]["status"], "unconfigured");
        assert_eq!(body["status"], "degraded");
    }

    #[tokio::test]
    async fn an_unreachable_upstream_degrades_the_service() {
        let (_prowlarr, transmission) = upstreams_up().await;

        // Port 1 is privileged and nothing binds it, so the probe gets a
        // refused connection immediately instead of waiting out the timeout.
        let state = AppState::new(Upstreams::new(
            "http://127.0.0.1:1".into(),
            format!("{}/transmission/rpc", transmission.uri()),
        ))
        .expect("state");

        let body = report(state).await;
        assert_eq!(body["status"], "degraded");
        assert_eq!(body["prowlarr"]["status"], "unreachable");
        assert_eq!(body["transmission"]["status"], "ok");
    }

    #[tokio::test]
    async fn an_upstream_answering_wrongly_is_unreachable() {
        let prowlarr = MockServer::start().await;
        Mock::given(method("GET"))
            .and(path("/ping"))
            .respond_with(ResponseTemplate::new(500))
            .mount(&prowlarr)
            .await;
        let transmission = MockServer::start().await;

        let state = AppState::new(Upstreams::new(
            prowlarr.uri(),
            format!("{}/transmission/rpc", transmission.uri()),
        ))
        .expect("state");

        let body = report(state).await;
        assert_eq!(body["prowlarr"]["status"], "unreachable");
        assert_eq!(body["prowlarr"]["detail"], "http 500");
    }

    #[tokio::test]
    async fn a_failed_tmdb_probe_never_echoes_the_api_key() {
        let (prowlarr, transmission) = upstreams_up().await;
        let tmdb = MockServer::start().await;
        Mock::given(method("GET"))
            .and(path("/configuration"))
            .respond_with(ResponseTemplate::new(401))
            .mount(&tmdb)
            .await;

        let state = AppState::new(
            Upstreams::new(
                prowlarr.uri(),
                format!("{}/transmission/rpc", transmission.uri()),
            )
            .with_tmdb_url(tmdb.uri())
            .with_tmdb_api_key(Some("super-secret".into())),
        )
        .expect("state");

        let body = report(state).await;
        assert_eq!(body["tmdb"]["status"], "unreachable");
        assert!(
            !body.to_string().contains("super-secret"),
            "the key must not reach the response body: {body}"
        );
    }

    #[test]
    fn the_document_is_generated_from_the_handler() {
        let document = openapi();
        let json = serde_json::to_value(&document).expect("serialise document");

        assert!(
            json["paths"]["/api/health"]["get"].is_object(),
            "the health route registered itself: {json}"
        );
        assert_eq!(json["paths"]["/api/health"]["get"]["tags"][0], "system");
        assert!(
            json["components"]["schemas"]["HealthReport"].is_object(),
            "the response body schema came along with it: {json}"
        );

        for (path, method) in [
            ("/api/movies", "get"),
            ("/api/movies", "post"),
            ("/api/movies/{movie_id}", "get"),
            ("/api/movies/{movie_id}", "patch"),
            ("/api/movies/{movie_id}", "delete"),
            ("/api/movies/{movie_id}/search", "post"),
            ("/api/movies/{movie_id}/releases", "get"),
            ("/api/movies/{movie_id}/releases/{release_id}/grab", "post"),
            ("/api/queues/attention", "get"),
        ] {
            assert!(
                json["paths"][path][method].is_object(),
                "missing {method} {path}"
            );
        }
        for schema in [
            "Movie",
            "CreateMovie",
            "UpdateMovie",
            "Release",
            "AttentionQueues",
        ] {
            assert!(
                json["components"]["schemas"][schema].is_object(),
                "{schema}"
            );
        }
    }

    #[tokio::test]
    async fn the_document_and_the_ui_are_served() {
        let state = AppState::new(Upstreams::new(
            "http://127.0.0.1:1".into(),
            "http://127.0.0.1:1".into(),
        ))
        .expect("state");
        let base = serve(state).await;

        let document: serde_json::Value = reqwest::get(format!("{base}{OPENAPI_PATH}"))
            .await
            .expect("fetch document")
            .json()
            .await
            .expect("document is json");
        assert!(document["paths"]["/api/health"].is_object());

        let docs = reqwest::get(format!("{base}{DOCS_PATH}"))
            .await
            .expect("fetch docs");
        assert_eq!(docs.status(), 200);
    }
}