/*
 * mCaptcha - A proof of work based DoS protection system
 * Copyright © 2023 Aravinth Manivannan <realravinth@batsense.net>
 *
 * 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 std::collections::HashMap;
use std::sync::Arc;

//use actix_web::web;
//use actix_web::web::Data;

use crate::app::DcacheApp;
use crate::DcacheNodeId;

use tokio::sync::mpsc;

#[derive(Debug)]
pub enum HealthStatus {
    Healthy(DcacheNodeId),
    Down(DcacheNodeId),
}

pub struct HealthMetrics;

impl HealthMetrics {
    pub async fn spawn(
        app: Arc<DcacheApp>,
        threshold: usize,
        mut rx: mpsc::Receiver<HealthStatus>,
    ) -> tokio::task::JoinHandle<()> {
        let mut current_error_rate = HashMap::new();
        let fut = async move {
            while let Some(msg) = rx.recv().await {
                match msg {
                    HealthStatus::Healthy(id) => {
                        current_error_rate.insert(id, 0);
                    }
                    HealthStatus::Down(id) => {
                        if let Some(existing_count) =
                            current_error_rate.get(&id).map(|s| s.to_owned())
                        {
                            current_error_rate.insert(id, existing_count + 1);
                            if existing_count == threshold {
                                let cluster_metrics = app.raft.metrics().borrow().clone();
                                let mut new_nodes: Vec<DcacheNodeId> = Vec::new();
                                for node in cluster_metrics.membership_config.nodes() {
                                    if *node.0 == id {
                                        continue;
                                    }

                                    new_nodes.push(*node.0);
                                }

                                let _res =
                                    app.raft.change_membership(new_nodes, false).await.unwrap();
                            }
                        } else {
                            current_error_rate.insert(id, 1);
                        }
                    }
                }
            }
        };

        tokio::spawn(fut)
    }
}