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// Copyright 2019-2021 Parity Technologies (UK) Ltd.
//
// Permission is hereby granted, free of charge, to any
// person obtaining a copy of this software and associated
// documentation files (the "Software"), to deal in the
// Software without restriction, including without
// limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of
// the Software, and to permit persons to whom the Software
// is furnished to do so, subject to the following
// conditions:
//
// The above copyright notice and this permission notice
// shall be included in all copies or substantial portions
// of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
// ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
// TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
// PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
// SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
// CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
// IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

//! RPC Logger layer.

use std::{
	pin::Pin,
	task::{Context, Poll},
};

use futures_util::Future;
use jsonrpsee_core::{
	server::MethodResponse,
	tracing::server::{rx_log_from_json, tx_log_from_str},
};
use jsonrpsee_types::Request;
use pin_project::pin_project;
use tracing::{instrument::Instrumented, Instrument};

use crate::middleware::rpc::RpcServiceT;

/// RPC logger layer.
#[derive(Copy, Clone, Debug)]
pub struct RpcLoggerLayer(u32);

impl RpcLoggerLayer {
	/// Create a new logging layer.
	pub fn new(max: u32) -> Self {
		Self(max)
	}
}

impl<S> tower::Layer<S> for RpcLoggerLayer {
	type Service = RpcLogger<S>;

	fn layer(&self, service: S) -> Self::Service {
		RpcLogger { service, max: self.0 }
	}
}

/// A middleware that logs each RPC call and response.
#[derive(Debug)]
pub struct RpcLogger<S> {
	max: u32,
	service: S,
}

impl<'a, S> RpcServiceT<'a> for RpcLogger<S>
where
	S: RpcServiceT<'a>,
{
	type Future = Instrumented<ResponseFuture<S::Future>>;

	#[tracing::instrument(name = "method_call", skip_all, fields(method = request.method_name()), level = "trace")]
	fn call(&self, request: Request<'a>) -> Self::Future {
		rx_log_from_json(&request, self.max);

		ResponseFuture { fut: self.service.call(request), max: self.max }.in_current_span()
	}
}

/// Response future to log the response for a method call.
#[pin_project]
pub struct ResponseFuture<F> {
	#[pin]
	fut: F,
	max: u32,
}

impl<F> std::fmt::Debug for ResponseFuture<F> {
	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
		f.write_str("ResponseFuture")
	}
}

impl<F: Future<Output = MethodResponse>> Future for ResponseFuture<F> {
	type Output = F::Output;

	fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
		let max = self.max;
		let fut = self.project().fut;

		let res = fut.poll(cx);
		if let Poll::Ready(rp) = &res {
			tx_log_from_str(rp.as_result(), max);
		}
		res
	}
}