// Copyright 2018 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
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// DEALINGS IN THE SOFTWARE.

//! Ping example
//!
//! See ../src/tutorial.rs for a step-by-step guide building the example below.
//!
//! In the first terminal window, run:
//!
//! ```sh
//! cargo run --example ping
//! ```
//!
//! It will print the PeerId and the listening address, e.g. `Listening on
//! "/ip4/0.0.0.0/tcp/24915"`
//!
//! In the second terminal window, start a new instance of the example with:
//!
//! ```sh
//! cargo run --example ping -- /ip4/127.0.0.1/tcp/24915
//! ```
//!
//! The two nodes establish a connection, negotiate the ping protocol
//! and begin pinging each other.

use futures::executor::block_on;
use futures::prelude::*;
use libp2p::ping::{Ping, PingConfig};
use libp2p::swarm::{Swarm, SwarmEvent};
use libp2p::{identity, PeerId};
use std::error::Error;
use std::task::Poll;

fn main() -> Result<(), Box<dyn Error>> {
    let local_key = identity::Keypair::generate_ed25519();
    let local_peer_id = PeerId::from(local_key.public());
    println!("Local peer id: {:?}", local_peer_id);

    let transport = block_on(libp2p::development_transport(local_key))?;

    // Create a ping network behaviour.
    //
    // For illustrative purposes, the ping protocol is configured to
    // keep the connection alive, so a continuous sequence of pings
    // can be observed.
    let behaviour = Ping::new(PingConfig::new().with_keep_alive(true));

    let mut swarm = Swarm::new(transport, behaviour, local_peer_id);

    // Tell the swarm to listen on all interfaces and a random, OS-assigned
    // port.
    swarm.listen_on("/ip4/0.0.0.0/tcp/0".parse()?)?;

    // Dial the peer identified by the multi-address given as the second
    // command-line argument, if any.
    if let Some(addr) = std::env::args().nth(1) {
        let remote = addr.parse()?;
        swarm.dial_addr(remote)?;
        println!("Dialed {}", addr)
    }

    block_on(future::poll_fn(move |cx| loop {
        match swarm.poll_next_unpin(cx) {
            Poll::Ready(Some(event)) => match event {
                SwarmEvent::NewListenAddr{ address, .. } => println!("Listening on {:?}", address),
                SwarmEvent::Behaviour(event) => println!("{:?}", event),
                _ => {}
            },
            Poll::Ready(None) => return Poll::Ready(()),
            Poll::Pending => return Poll::Pending,
        }
    }));

    Ok(())
}