// Copyright 2015, 2016 Ethcore (UK) Ltd.
// This file is part of Parity.

// Parity is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// Parity 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 General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with Parity.  If not, see <http://www.gnu.org/licenses/>.

//! IPC over nanomsg transport

extern crate ethcore_ipc as ipc;
extern crate nanomsg;
#[macro_use] extern crate log;

pub use ipc::*;

use std::sync::*;
use std::io::Write;
use nanomsg::{Socket, Protocol};

pub struct Worker<S> where S: IpcInterface<S> {
	service: Arc<S>,
	sockets: Vec<Socket>,
	method_buf: [u8;2],
}

pub enum SocketError {
	DuplexLink
}

impl<S> Worker<S> where S: IpcInterface<S> {
	pub fn new(service: Arc<S>) -> Worker<S> {
		Worker::<S> {
			service: service.clone(),
			sockets: Vec::new(),
			method_buf: [0,0]
		}
	}

	pub fn poll(&mut self) {
		for socket in self.sockets.iter_mut() {
			// non-blocking read only ok if there is something to read from socket
			if let Ok(method_sign_len) = socket.nb_read(&mut self.method_buf) {
				if method_sign_len == 2 {
					let result = self.service.dispatch_buf(
						self.method_buf[1] as u16 * 256 + self.method_buf[0] as u16,
						socket);
					if let Err(e) = socket.write(&result) {
						warn!(target: "ipc", "Failed to write response: {:?}", e);
					}
				}
				else {
					warn!(target: "ipc", "Failed to read method signature from socket: unexpected message length({})", method_sign_len);
				}
			}
		}
	}

	pub fn add_duplex(&mut self, addr: &str) -> Result<(), SocketError>  {
		let mut socket = try!(Socket::new(Protocol::Pair).map_err(|e| {
			warn!(target: "ipc", "Failed to create ipc socket: {:?}", e);
			SocketError::DuplexLink
		}));

		try!(socket.bind(addr).map_err(|e| {
			warn!(target: "ipc", "Failed to bind socket to address '{}': {:?}", addr, e);
			SocketError::DuplexLink
		}));

		self.sockets.push(socket);
		Ok(())
	}
}

#[cfg(test)]
mod tests {

	use super::Worker;
	use ipc::*;
	use std::io::Read;
	use std::sync::Arc;

	struct DummyService;

	impl IpcInterface<DummyService> for DummyService {
		fn dispatch<R>(&self, r: &mut R) -> Vec<u8> where R: Read {
			vec![]
		}
		fn dispatch_buf<R>(&self, method_num: u16, r: &mut R) -> Vec<u8> where R: Read {
			vec![]
		}
	}

	#[test]
	fn can_create_worker() {
		let worker = Worker::<DummyService>::new(Arc::new(DummyService));
		assert_eq!(0, worker.sockets.len());
	}
}