// Copyright (C) 2021 Quickwit, Inc.
//
// Quickwit is offered under the AGPL v3.0 and as commercial software.
// For commercial licensing, contact us at hello@quickwit.io.
//
// AGPL:
// 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 <http://www.gnu.org/licenses/>.

use prometheus::{Encoder, IntCounter, IntGauge, Opts, TextEncoder};

pub fn new_counter(name: &str, description: &str) -> IntCounter {
    let counter =
        IntCounter::with_opts(Opts::new(name, description)).expect("Failed to create counter");
    prometheus::register(Box::new(counter.clone())).expect("Failed to register counter");
    counter
}

pub fn new_gauge(name: &str, description: &str) -> IntGauge {
    let gauge = IntGauge::with_opts(Opts::new(name, description)).expect("Failed to create gauge");
    prometheus::register(Box::new(gauge.clone())).expect("Failed to register gauge");
    gauge
}

pub fn metrics_handler() -> impl warp::Reply {
    let metric_families = prometheus::gather();
    let mut buffer = Vec::new();
    let encoder = TextEncoder::new();
    let _ = encoder.encode(&metric_families, &mut buffer); // TODO avoid ignoring the error.
    String::from_utf8_lossy(&buffer).to_string()
}