use std::net::SocketAddr;
use askama::Template;
use axum::{
    extract::State,
    routing::post,
    http::StatusCode,
    response::{IntoResponse, Response},
    Json, Router,
};
use serde::Deserialize;

mod jabber;
mod prometheus_alert;

enum Payload {
    Prometheus(prometheus_alert::Payload),
}

impl Payload {
    fn render(&self) -> Result<String, askama::Error> {
        match self {
            Payload::Prometheus(payload) => payload.render(),
        }
    }

    async fn handle_payload(&self, jabber: jabber::Handle) -> Response {
        let mut error_message = None;

        match self.render() {
            Ok(message) => {
                jabber.send_message(message).await;
            }
            Err(e) => {
                error_message = Some(format!("{}", e));
            }
        }

        match error_message {
            None =>
                StatusCode::OK.into_response(),
            Some(error_message) =>
                (StatusCode::INTERNAL_SERVER_ERROR,
                 error_message
                ).into_response()
        }
    }
}

async fn alerts(
    State(jabber): State<jabber::Handle>,
    Json(payload): Json<prometheus_alert::Payload>,
) -> Response {
    Payload::Prometheus(payload)
        .handle_payload(jabber)
        .await
}

#[derive(Deserialize)]
struct Config {
    listen_port: u16,
    jid: String,
    password: String,
    muc: String,
}

#[tokio::main]
async fn main() {
    // initialize tracing
    tracing_subscriber::fmt::init();

    let config: Config = serde_json::from_str(
        &std::fs::read_to_string(
            std::env::args().nth(1)
                .expect("Call with config.json")
        ).expect("read config")
    ).expect("parse config");
    let jabber = jabber::run(config.jid, config.password, config.muc).await;

    // build our application with a route
    let app = Router::new()
        .route("/alert", post(alerts))
        .with_state(jabber);

    let addr = SocketAddr::from(([127, 0, 0, 1], config.listen_port));
    tracing::debug!("listening on {}", addr);
    let server = axum::Server::bind(&addr)
        .serve(app.into_make_service());
    systemd::daemon::notify(false, [(systemd::daemon::STATE_READY, "1")].iter())
        .unwrap();
    server.await
        .unwrap();
}