/********************************************************************************
 *   Prometheus exporter for monitoring network connectivity using icmp pings   *
 *                                                                              *
 *   Copyright (C) 2019-2022 Jan Christian Grünhage                             *
 *   Copyright (C) 2020-2021 Famedly GmbH                                            *
 *                                                                              *
 *   This program is free software: you can redistribute it and/or modify       *
 *   it under the terms of the GNU Affero General Public License as             *
 *   published by the Free Software Foundation, either version 3 of the         *
 *   License, or (at your option) any later version.                            *
 *                                                                              *
 *   This program is distributed in the hope that it will be useful,            *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of             *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the               *
 *   GNU Affero General Public License for more details.                        *
 *                                                                              *
 *   You should have received a copy of the GNU Affero General Public License   *
 *   along with this program.  If not, see <https://www.gnu.org/licenses/>.     *
 ********************************************************************************/
use crate::config::Config;
use anyhow::Result;
use axum::{response::IntoResponse, routing::get, Router, Server};
use log::info;
use metrics_exporter_prometheus::PrometheusHandle;

async fn metrics(handle: PrometheusHandle) -> impl IntoResponse {
    handle.render()
}

pub(crate) async fn start_serving_metrics(config: &Config, handle: PrometheusHandle) -> Result<()> {
    let app = Router::new()
        .route(
            "/metrics",
            get({
                let handle = handle.clone();
                move || metrics(handle)
            }),
        )
        .route("/health", get(|| async { "" }));
    let serve_future = Server::bind(&config.listener).serve(app.into_make_service());
    info!("Listening on {}", &config.listener);
    Ok(serve_future.await?)
}