mod blockfetch;
mod chainsync;
mod channel;
mod stream;
mod txsubmit;

pub mod packet;

use cardano_sdk::chaininfo::ChainInfo;
use cardano_sdk::protocol::{
    BlockFetch, ChainSync, DiffusionMode, Point, Protocol, TxSubmit, Version,
};
use std::collections::HashMap;
use std::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr};
use std::str::FromStr;
use stream::StreamStatsShared;
use thiserror::*;
use tokio::net::TcpStream;
use tracing::{debug, info};

use trust_dns_resolver::{config::*, TokioAsyncResolver};

pub use blockfetch::BlockFetcher;
pub use chainsync::ChainIntersection;
pub use channel::Channel;
use packet::rawchan::{ChannelWriter, RawChannel};
pub use packet::{frame::PacketBytes, ProtocolError};
pub use txsubmit::SubmitNext;

#[derive(Clone, Debug)]
pub struct NetworkDescription {
    pub anchor_hosts: Vec<(String, u16)>,
    pub chain_info: ChainInfo,
    pub net_versions: Vec<Version>,
    pub known_points: Vec<(u64, Point)>,
}

impl NetworkDescription {
    pub fn mainnet() -> Self {
        Self {
            anchor_hosts: vec![(String::from("relays-new.cardano-mainnet.iohk.io."), 3001)],
            chain_info: ChainInfo::MAINNET,
            net_versions: vec![Version::V6, Version::V7, Version::V8],
            known_points: vec![(
                1,
                Point::from_raw(
                    0,
                    "f0f7892b5c333cffc4b3c4344de48af4cc63f55e44936196f365a9ef2244134f",
                )
                .unwrap(),
            )],
        }
    }

    pub fn testnet() -> Self {
        Self {
            anchor_hosts: vec![(String::from("relays-new.cardano-testnet.iohkdev.io."), 3001)],
            chain_info: ChainInfo::TESTNET,
            net_versions: vec![Version::V6, Version::V7, Version::V8],
            known_points: vec![
                (
                    1,
                    Point::from_raw(
                        1031,
                        "388a82f053603f3552717d61644a353188f2d5500f4c6354cc1ad27a36a7ea91",
                    )
                    .unwrap(),
                ),
                // shelley
                (
                    1597133,
                    Point::from_raw(
                        1598400,
                        "02b1c561715da9e540411123a6135ee319b02f60b9a11a603d3305556c04329f",
                    )
                    .unwrap(),
                ),
                // after shelley
                (
                    2349176,
                    Point::from_raw(
                        19742400,
                        "80095b5d08fe5a97581f4ba940cb91410eb88673f581fc61785608718553fab6",
                    )
                    .unwrap(),
                ),
            ],
        }
    }

    pub fn preprod() -> Self {
        Self {
            anchor_hosts: vec![(String::from("preprod-node.world.dev.cardano.org."), 30000)],
            chain_info: ChainInfo::PREPROD,
            net_versions: vec![Version::V6, Version::V7, Version::V8],
            known_points: vec![(
                // shelley
                46,
                Point::from_raw(
                    86400,
                    "c4a1595c5cc7a31eda9e544986fe9387af4e3491afe0ca9a80714f01951bbd5c",
                )
                .unwrap(),
            )],
        }
    }

    pub fn preview() -> Self {
        Self {
            anchor_hosts: vec![(String::from("preview-node.world.dev.cardano.org."), 30002)],
            chain_info: ChainInfo::PREVIEW,
            net_versions: vec![Version::V6, Version::V7, Version::V8],
            known_points: vec![(
                // shelley
                505,
                Point::from_raw(
                    86400,
                    "283b30cedbfc17647564abb43012bd2f17871ec0be748535c38a52088ced6a9f",
                )
                .unwrap(),
            )],
        }
    }

    pub fn override_hosts(mut self, v: &[(String, u16)]) -> Self {
        self.anchor_hosts = v.to_owned();
        self
    }
}

async fn resolve_name(dest: &str) -> Result<Vec<IpAddr>, ()> {
    let ip = match Ipv4Addr::from_str(dest) {
        Ok(addr) => Some(IpAddr::V4(addr)),
        Err(_) => match Ipv6Addr::from_str(dest) {
            Ok(addr6) => Some(IpAddr::V6(addr6)),
            Err(_) => None,
        },
    };

    match ip {
        // possibly a host then
        None => {
            let resolver =
                TokioAsyncResolver::tokio(ResolverConfig::default(), ResolverOpts::default())
                    .unwrap();
            let response = resolver.lookup_ip(dest).await.unwrap();
            let addresses = response.iter().collect::<Vec<_>>();
            Ok(addresses)
        }
        Some(ip) => Ok(vec![ip]),
    }
}

async fn connect_to(
    destinations: &[(String, u16)],
) -> Result<(SocketAddr, TcpStream), Vec<std::io::Error>> {
    let mut errors = Vec::new();

    for (dest, port) in destinations {
        let ip_addresses = resolve_name(dest).await.unwrap();

        // try to connect from (resolved) ip addresses at the expected port
        for ip_addr in ip_addresses {
            let addr = SocketAddr::new(ip_addr, *port);
            debug!("trying to connect to {}:{} ({})", dest, port, ip_addr);
            match TcpStream::connect(&addr).await {
                Err(e) => errors.push(e),
                Ok(stream) => {
                    info!("connected to {}:{} ({})", dest, port, ip_addr);
                    return Ok((addr, stream));
                }
            }
        }
    }

    return Err(errors);
}

pub struct NetworkHandle {
    #[allow(dead_code)]
    handle: tokio::task::JoinHandle<()>,

    /// the socket address of the opposite side
    pub sockaddr: SocketAddr,
    /// chainsync sub protocol
    pub chainsync: Channel<ChainSync>,
    /// txsubmit sub protocol
    pub txsubmit: Channel<TxSubmit>,
    /// blockfetch sub protocol
    pub blockfetch: Channel<BlockFetch>,
    /// Stats for the stream
    pub stats: StreamStatsShared,
}

#[derive(Debug, Error)]
pub enum NetworkError {
    #[error("protocol error {0}")]
    ProtocolError(#[from] ProtocolError),
    #[error("handshake error {0}")]
    HandshakeError(#[from] stream::HandshakeError),
    #[error("Connect I/O error {0:?}")]
    ConnectError(Vec<std::io::Error>),
}

fn channel<P: Protocol>(
    writer: tokio::sync::mpsc::Sender<PacketBytes>,
) -> (ChannelWriter, Channel<P>) {
    let (sender, receiver) = tokio::sync::mpsc::channel(16);
    let channel = RawChannel::new(P::NUMBER, writer, receiver);
    (ChannelWriter(sender), Channel::new(channel))
}

impl NetworkHandle {
    /// Connect to the network with the expected parameters, perform the protocol handshake
    /// and in the background wait for packet to send and receive.
    pub async fn start(
        network_description: &NetworkDescription,
    ) -> Result<NetworkHandle, NetworkError> {
        // try to connect to one of the known anchors in network_description
        let (sockaddr, tcp) = connect_to(&network_description.anchor_hosts)
            .await
            .map_err(|e| NetworkError::ConnectError(e))?;

        let (tx_sender, tx_receiver) = tokio::sync::mpsc::channel(64);

        let (chainsync_w, chainsync) = channel(tx_sender.clone());
        let (txsubmit_w, txsubmit) = channel(tx_sender.clone());
        let (blockfetch_w, blockfetch) = channel(tx_sender);
        let channels = HashMap::from([
            (ChainSync::NUMBER, chainsync_w),
            (TxSubmit::NUMBER, txsubmit_w),
            (BlockFetch::NUMBER, blockfetch_w),
        ]);

        let stats = stream::StreamStatsShared::default();

        // create a cardano stream, perform the handshake with the connected client
        // and then create the receiving / sending loop
        let mut stream = stream::Stream::new(stats.clone(), tcp, tx_receiver, channels);
        stream
            .handshake(
                network_description.chain_info.protocol_magic,
                DiffusionMode::InitiatorOnly,
                &network_description.net_versions,
            )
            .await??;

        let handle = tokio::spawn(async move { stream.process_fragment().await });

        Ok(NetworkHandle {
            sockaddr,
            handle,
            chainsync,
            blockfetch,
            txsubmit,
            stats,
        })
    }

    pub async fn stop(self) {
        self.handle.abort()
    }
}