// 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
// 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.

use futures::stream::StreamExt;
use libp2p::{
    gossipsub, mdns, noise,
    swarm::{NetworkBehaviour, SwarmEvent},
    tcp, yamux,
};
use std::time::Duration;
use std::{error::Error, hash::Hash};
use tokio::{io, io::AsyncBufReadExt, select};
use tracing_subscriber::EnvFilter;

// We create a custom network behaviour that combines Gossipsub and Mdns.
#[derive(NetworkBehaviour)]
struct MyBehaviour {
    gossipsub: gossipsub::Behaviour,
    mdns: mdns::tokio::Behaviour,
}

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    let _ = tracing_subscriber::fmt()
        .with_env_filter(EnvFilter::from_default_env())
        .try_init();

    let mut swarm = libp2p::SwarmBuilder::with_new_identity()
        .with_tokio()
        .with_tcp(
            tcp::Config::default(),
            noise::Config::new,
            yamux::Config::default,
        )?
        .with_behaviour(|key| {
            // Set a custom gossipsub configuration
            let gossipsub_config = gossipsub::ConfigBuilder::default()
                .heartbeat_interval(Duration::from_secs(10))
                .validation_mode(gossipsub::ValidationMode::Strict) // This sets the kind of message validation. The default is Strict (enforce message signing)
                .build()
                .map_err(io::Error::other)?; // Temporary hack because `build` does not return a proper `std::error::Error`.

            // build a gossipsub network behaviour
            let gossipsub = gossipsub::Behaviour::new(
                gossipsub::MessageAuthenticity::Signed(key.clone()),
                gossipsub_config,
            )?;

            let mdns =
                mdns::tokio::Behaviour::new(mdns::Config::default(), key.public().to_peer_id())?;
            Ok(MyBehaviour { gossipsub, mdns })
        })?
        .build();

    println!("Running swarm with identity {}", swarm.local_peer_id());

    // Create a Gossipsub topic
    let topic = gossipsub::IdentTopic::new("test-net");
    // subscribes to our topic
    swarm.behaviour_mut().gossipsub.subscribe(&topic)?;

    // Read full lines from stdin
    let mut stdin = io::BufReader::new(io::stdin()).lines();

    // Listen on all interfaces and whatever port the OS assigns
    swarm.listen_on("/ip4/0.0.0.0/tcp/0".parse()?)?;

    println!("Enter messages via STDIN and they will be sent to connected peers using Gossipsub");

    // Kick it off
    loop {
        select! {
            Ok(Some(line)) = stdin.next_line() => {
                if let Err(e) = swarm
                    .behaviour_mut().gossipsub
                    .publish(topic.clone(), line.as_bytes()) {
                    println!("Publish error: {e:?}");
                }
            }
            event = swarm.select_next_some() => match event {
                SwarmEvent::Behaviour(MyBehaviourEvent::Mdns(mdns::Event::Discovered(list))) => {
                    for (peer_id, multiaddr) in list {
                        println!("mDNS discovered a new peer: {peer_id} on {multiaddr}");
                        swarm.behaviour_mut().gossipsub.add_explicit_peer(&peer_id);
                    }
                },
                SwarmEvent::Behaviour(MyBehaviourEvent::Mdns(mdns::Event::Expired(list))) => {
                    for (peer_id, multiaddr) in list {
                        println!("mDNS discover peer has expired: {peer_id} on {multiaddr}");
                        swarm.behaviour_mut().gossipsub.remove_explicit_peer(&peer_id);
                    }
                },
                SwarmEvent::Behaviour(MyBehaviourEvent::Gossipsub(gossipsub::Event::Message {
                    propagation_source: peer_id,
                    message_id: id,
                    message,
                })) => println!(
                        "Got message: '{}' with id: {id} from peer: {peer_id}",
                        String::from_utf8_lossy(&message.data),
                    ),
                SwarmEvent::NewListenAddr { address, .. } => {
                    println!("Local node is listening on {address}");
                }
                e => {
                    println!("Other swarm event: {:?}", e);
                }
            }
        }
    }
}
