//  Copyright 2020, The Tari Project
//
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//  following conditions are met:
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//  1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following
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use std::task::Poll;

use futures::task::Context;
use log::*;
use tari_comms::message::InboundMessage;
use tower::{Service, layer::Layer};

use crate::connectivity::MetricsCollectorHandle;

const LOG_TARGET: &str = "comms::dht::metrics";

#[derive(Clone)]
pub struct Metrics<S> {
    next_service: S,
    metric_collector: MetricsCollectorHandle,
}

impl<S> Metrics<S> {
    pub fn new(service: S, metric_collector: MetricsCollectorHandle) -> Self {
        Self {
            next_service: service,
            metric_collector,
        }
    }
}

impl<S> Service<InboundMessage> for Metrics<S>
where S: Service<InboundMessage> + Clone + 'static
{
    type Error = S::Error;
    type Future = S::Future;
    type Response = S::Response;

    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
        self.next_service.poll_ready(cx)
    }

    fn call(&mut self, message: InboundMessage) -> Self::Future {
        if !self
            .metric_collector
            .write_metric_message_received(message.source_peer.clone())
        {
            debug!(target: LOG_TARGET, "Unable to write metric");
        }

        self.next_service.call(message)
    }
}

pub struct MetricsLayer {
    metric_collector: MetricsCollectorHandle,
}

impl MetricsLayer {
    pub fn new(metric_collector: MetricsCollectorHandle) -> Self {
        Self { metric_collector }
    }
}

impl<S> Layer<S> for MetricsLayer {
    type Service = Metrics<S>;

    fn layer(&self, service: S) -> Self::Service {
        Metrics::new(service, self.metric_collector.clone())
    }
}
