use ed25519_dalek::ed25519::signature::SignerMut;
use std::error::Error;
use tokio::{io, io::AsyncBufReadExt, select};

use futures::prelude::*;
use libp2p::{
    mdns,
    request_response::{self, ProtocolSupport},
    swarm::SwarmEvent,
    Multiaddr,
};
use tracing_subscriber::EnvFilter;

use cll2v0::{
    keys,
    messages::MyRequest,
    protocol::{mk_swarm, MyBehaviourEvent},
};

use clap::{Parser, Subcommand};

/// cll2v0 is a playground for rust libraries.
/// This is signing service.
#[derive(Parser)]
#[command(arg_required_else_help(true), version, about)]
struct Args {
    #[command(subcommand)]
    cmd: Option<Command>,
}

#[derive(Subcommand)]
enum Command {
    /// Start server
    Start(ClientParams),
}

#[derive(clap::Args, Debug)]
pub struct ClientParams {
    /// Root of the multiaddr
    #[arg(
        long,
        default_value = "/ip4/0.0.0.0/tcp/52321/p2p/12D3KooWPADMrTD3njNGBwyiqFEaDSarki8bQJdiFtofo8sGXs1o"
    )]
    pub server_addr: String,
    // pub listen_on : String,
    /// If used in prod, this should be an envvar.
    #[arg(
        long,
        default_value = "0000000000000000000000000000000000000000000000000000000000000000"
    )]
    pub skey: String,
    // FIXME :: rust does not like this option /// If turn trace on
    // pub trace: bool,
}

fn main() -> Result<(), Box<dyn Error>> {
    match Args::parse().cmd {
        Some(Command::Start(sp)) => tokio::runtime::Builder::new_multi_thread()
            .enable_all()
            .build()
            .unwrap()
            .block_on(start(sp)),
        _ => {
            panic!("oops")
        }
    }
}

pub async fn start(params: ClientParams) -> Result<(), Box<dyn Error>> {
    println!("params {:?}", params);
    let ClientParams {
        server_addr,
        skey: skey_hex,
    } = params;
    if true {
        let _ = tracing_subscriber::fmt()
            .with_env_filter(EnvFilter::from_default_env())
            .try_init();
    }

    let key = keys::signing_key_from_hex(&skey_hex)?;
    println!("VERIFYING : {}", keys::to_hex(&key.verifying_key()));

    let keypair = keys::libp2p_kp_from_hex(skey_hex)?;

    let mut swarm = mk_swarm(&keypair.clone().into(), ProtocolSupport::Outbound)?;
    swarm.listen_on("/ip4/0.0.0.0/tcp/0".parse()?)?;

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

    let server_addr: libp2p::Multiaddr = server_addr.parse()?;
    let server_peer_id = match server_addr.clone().pop() {
        Some(libp2p::multiaddr::Protocol::P2p(peer_id)) => peer_id,
        _ => panic!("must end in peer"),
    };
    println!("server addr : {:?}, {:?}", server_addr, server_peer_id);
    let _res = swarm.dial(server_addr)?;

    loop {
        select! {
            Ok(Some(line)) = stdin.next_line() => {
                println!("MESSAGE: {}", line);
                let bytes = line.into_bytes();
                let req = MyRequest {
                        key: keypair.clone().public().to_bytes(),
                        body: bytes.clone(),
                        sig: keys::sign(&mut key.clone(), bytes).to_vec(),
                    };
                println!("REQ : {:?}", req);
                swarm.behaviour_mut().req_res.send_request(
                    &server_peer_id,
                    req,
                );
            }
            event = swarm.select_next_some() => match event {
                // MDNS BEHAVIOR
                SwarmEvent::Behaviour(MyBehaviourEvent::Mdns(mdns::Event::Discovered(list))) => {
                    for (peer_id, multiaddr) in list {
                        println!("add peer {:?}, {:?}", peer_id, multiaddr.clone());
                        // swarm.dial(multiaddr)?;
                    }
                }
                // SwarmEvent::Behaviour(MyBehaviourEvent::Mdns(mdns::Event::Expired(list))) => {
                //     for (peer_id, _multiaddr) in list {
                //         println!("mDNS discover peer has expired: {peer_id}");
                //         // swarm.behaviour_mut().gossipsub.remove_explicit_peer(&peer_id);
                //     }
                // }
                // SwarmEvent::Behaviour(MyBehaviourEvent::ReqRes(request_response::Event::Message {
                //     peer: _peer,
                //     message:
                //         libp2p::request_response::Message::Request {
                //             request, channel, ..
                //         },
                // })) => {
                //     // println!("Req : {:?} {:?} {:?}", peer, channel, hex::encode(request.body.clone()), );
                //     println!("REQSIG : {}", hex::encode(request.sig.clone()),);
                //     let _ = swarm.behaviour_mut().req_res.send_response(
                //         channel,
                //         MyResponse {
                //             sig: keypair.sign(&request.body),
                //         },
                //     );
                // }
                SwarmEvent::Behaviour(MyBehaviourEvent::ReqRes(request_response::Event::Message {
                    peer: _peer,
                    message: libp2p::request_response::Message::Response { response, .. },
                })) => {
                    // println!("response : {:?} {:?} {:?}", peer, request_id, "" );
                    println!("RESSIG : {}", hex::encode(response.sig.clone()),);
                }
                e => {
                    println!("OTHER {:?}", e)
                }
            }
        }
    }
}