darkfi/bin/ircd/src/irc/client.rs

use std::net::SocketAddr;

use futures::{
    io::{BufReader, ReadHalf, WriteHalf},
    AsyncBufReadExt, AsyncRead, AsyncWrite, AsyncWriteExt, FutureExt,
};
use fxhash::FxHashMap;
use log::{debug, error, info, warn};

use darkfi::{
    net::P2pPtr,
    system::{SubscriberPtr, Subscription},
    Error, Result,
};

use crate::{
    buffers::{ArcPrivmsgsBuffer, SeenIds},
    crypto::{decrypt_privmsg, decrypt_target, encrypt_privmsg},
    privmsg::{MAXIMUM_LENGTH_OF_MESSAGE, MAXIMUM_LENGTH_OF_NICKNAME},
    ChannelInfo, ContactInfo, Privmsg,
};

const RPL_NOTOPIC: u32 = 331;
const RPL_TOPIC: u32 = 332;
const RPL_NAMEREPLY: u32 = 353;
const RPL_ENDOFNAMES: u32 = 366;

pub struct IrcClient<C: AsyncRead + AsyncWrite + Send + Unpin + 'static> {
    // network stream
    write_stream: WriteHalf<C>,
    pub address: SocketAddr,

    // msgs buffer
    privmsgs_buffer: ArcPrivmsgsBuffer,
    seen_msg_ids: SeenIds,

    // init bool
    is_nick_init: bool,
    is_user_init: bool,
    is_registered: bool,
    is_cap_end: bool,
    is_pass_init: bool,

    // user config
    nickname: String,
    password: String,
    capabilities: FxHashMap<String, bool>,

    // channels and contacts
    auto_channels: Vec<String>,
    pub configured_chans: FxHashMap<String, ChannelInfo>,
    pub configured_contacts: FxHashMap<String, ContactInfo>,

    // p2p
    p2p: P2pPtr,
    p2p_notifiers: SubscriberPtr<Privmsg>,
    subscription: Subscription<Privmsg>,
}

impl<C: AsyncRead + AsyncWrite + Send + Unpin + 'static> IrcClient<C> {
    #[allow(clippy::too_many_arguments)]
    pub fn new(
        write_stream: WriteHalf<C>,
        address: SocketAddr,
        privmsgs_buffer: ArcPrivmsgsBuffer,
        seen_msg_ids: SeenIds,
        password: String,
        auto_channels: Vec<String>,
        configured_chans: FxHashMap<String, ChannelInfo>,
        configured_contacts: FxHashMap<String, ContactInfo>,
        p2p: P2pPtr,
        p2p_notifiers: SubscriberPtr<Privmsg>,
        subscription: Subscription<Privmsg>,
    ) -> Self {
        let mut capabilities = FxHashMap::default();
        capabilities.insert("no-history".to_string(), false);
        Self {
            write_stream,
            address,
            privmsgs_buffer,
            seen_msg_ids,
            is_nick_init: false,
            is_user_init: false,
            is_registered: false,
            is_cap_end: true,
            is_pass_init: false,
            nickname: "anon".to_string(),
            password,
            auto_channels,
            configured_chans,
            configured_contacts,
            capabilities,
            p2p,
            p2p_notifiers,
            subscription,
        }
    }

    /// Start listening for messages came from p2p network or irc client
    pub async fn listen(&mut self, mut reader: BufReader<ReadHalf<C>>) {
        loop {
            let mut line = String::new();

            futures::select! {
                msg = self.subscription.receive().fuse() => {
                    if let Err(e) = self.process_msg_from_p2p(&msg).await {
                        error!("[CLIENT {}] Process msg from p2p: {}",  self.address, e);
                        break
                    }
                }
                err = reader.read_line(&mut line).fuse() => {
                    if let Err(e) = self.process_line(err, line).await {
                        error!("[CLIENT {}] Process line failed: {}",  self.address, e);
                        break
                    }
                }
            }
        }

        warn!("[CLIENT {}] Close connection", self.address);
        self.subscription.unsubscribe().await;
    }

    pub async fn process_msg_from_p2p(&mut self, msg: &Privmsg) -> Result<()> {
        info!("[P2P] Received: {}", msg.to_string().trim());

        let mut msg = msg.clone();
        let mut contact = String::new();
        decrypt_target(
            &mut contact,
            &mut msg,
            self.configured_chans.clone(),
            self.configured_contacts.clone(),
        );
        if msg.target.starts_with('#') {
            // Try to potentially decrypt the incoming message.
            if !self.configured_chans.contains_key(&msg.target) {
                return Ok(())
            }

            let chan_info = self.configured_chans.get_mut(&msg.target).unwrap();
            if !chan_info.joined {
                return Ok(())
            }

            if let Some(salt_box) = &chan_info.salt_box {
                decrypt_privmsg(salt_box, &mut msg);
                info!("Decrypted received message: {:?}", msg);
            }

            // add the nickname to the channel's names
            if !chan_info.names.contains(&msg.nickname) {
                chan_info.names.push(msg.nickname.clone());
            }

            self.reply(&msg.to_string()).await?;
            return Ok(())
        } else if self.is_cap_end && self.is_nick_init {
            if !self.configured_contacts.contains_key(&contact) {
                return Ok(())
            }

            let contact_info = self.configured_contacts.get(&contact).unwrap();
            if let Some(salt_box) = &contact_info.salt_box {
                decrypt_privmsg(salt_box, &mut msg);
                // This is for /query
                msg.nickname = contact;
                info!("[P2P] Decrypted received message: {:?}", msg);
            }

            self.reply(&msg.to_string()).await?;
        }

        Ok(())
    }

    pub async fn process_line(
        &mut self,
        err: std::result::Result<usize, std::io::Error>,
        line: String,
    ) -> Result<()> {
        if let Err(e) = err {
            warn!("[CLIENT {}] Read line error: {}", self.address, e);
            return Err(Error::ChannelStopped)
        }

        let irc_msg = match clean_input_line(line) {
            Ok(msg) => msg,
            Err(e) => {
                warn!("[CLIENT {}] Connection error: {}", self.address, e);
                return Err(Error::ChannelStopped)
            }
        };

        info!("[CLIENT {}] Msg: {}", self.address, irc_msg);

        if let Err(e) = self.update(irc_msg).await {
            warn!("[CLIENT {}] Connection error: {}", self.address, e);
            return Err(Error::ChannelStopped)
        }
        Ok(())
    }

    async fn update(&mut self, line: String) -> Result<()> {
        if line.len() > MAXIMUM_LENGTH_OF_MESSAGE {
            return Err(Error::MalformedPacket)
        }

        if self.password.is_empty() {
            self.is_pass_init = true
        }

        let (command, value) = parse_line(&line)?;
        let (command, value) = (command.as_str(), value.as_str());

        match command {
            "PASS" => self.on_receive_pass(value).await?,
            "USER" => self.on_receive_user().await?,
            "NAMES" => self.on_receive_names(value.split(',').map(String::from).collect()).await?,
            "NICK" => self.on_receive_nick(value).await?,
            "JOIN" => self.on_receive_join(value.split(',').map(String::from).collect()).await?,
            "PART" => self.on_receive_part(value.split(',').map(String::from).collect()).await?,
            "TOPIC" => self.on_receive_topic(&line, value).await?,
            "PING" => self.on_ping(value).await?,
            "PRIVMSG" => self.on_receive_privmsg(&line, value).await?,
            "CAP" => self.on_receive_cap(&line, &value.to_uppercase()).await?,
            "QUIT" => self.on_quit()?,
            _ => warn!("[CLIENT {}] Unimplemented `{}` command", self.address, command),
        }

        self.registre().await?;
        Ok(())
    }

    async fn registre(&mut self) -> Result<()> {
        if !self.is_registered && self.is_cap_end && self.is_nick_init && self.is_user_init {
            debug!("Initializing peer connection");
            let register_reply = format!(":darkfi 001 {} :Let there be dark\r\n", self.nickname);
            self.reply(&register_reply).await?;
            self.is_registered = true;

            self.on_receive_join(self.auto_channels.clone()).await?;

            if *self.capabilities.get("no-history").unwrap() {
                return Ok(())
            }

            // Send dm messages in buffer
            let privmsgs_buffer = self.privmsgs_buffer.lock().await;
            for msg in privmsgs_buffer.iter() {
                let is_dm = msg.target == self.nickname ||
                    (msg.nickname == self.nickname && !msg.target.starts_with('#'));

                if is_dm {
                    self.p2p_notifiers.notify_by_id(msg.clone(), self.subscription.get_id()).await;
                }
            }
            drop(privmsgs_buffer);
        }
        Ok(())
    }

    async fn reply(&mut self, message: &str) -> Result<()> {
        self.write_stream.write_all(message.as_bytes()).await?;
        debug!("Sent {}", message);
        Ok(())
    }

    fn on_quit(&self) -> Result<()> {
        // Close the connection
        Err(Error::NetworkServiceStopped)
    }

    async fn on_receive_user(&mut self) -> Result<()> {
        // We can stuff any extra things like public keys in here.
        // Ignore it for now.
        if self.is_pass_init {
            self.is_user_init = true;
        } else {
            // Close the connection
            warn!("[IRC SERVER] Password is required");
            return self.on_quit()
        }
        Ok(())
    }

    async fn on_receive_pass(&mut self, password: &str) -> Result<()> {
        if self.password == password {
            self.is_pass_init = true
        } else {
            // Close the connection
            warn!("[IRC SERVER] Password is not correct!");
            return self.on_quit()
        }
        Ok(())
    }

    async fn on_receive_nick(&mut self, nickname: &str) -> Result<()> {
        if nickname.len() > MAXIMUM_LENGTH_OF_NICKNAME {
            return Ok(())
        }

        self.is_nick_init = true;
        let old_nick = std::mem::replace(&mut self.nickname, nickname.to_string());

        let nick_reply = format!(":{}!anon@dark.fi NICK {}\r\n", old_nick, self.nickname);
        self.reply(&nick_reply).await
    }

    async fn on_receive_part(&mut self, channels: Vec<String>) -> Result<()> {
        for chan in channels.iter() {
            let part_reply = format!(":{}!anon@dark.fi PART {}\r\n", self.nickname, chan);
            self.reply(&part_reply).await?;
            if self.configured_chans.contains_key(chan) {
                let chan_info = self.configured_chans.get_mut(chan).unwrap();
                chan_info.joined = false;
            }
        }
        Ok(())
    }

    async fn on_receive_topic(&mut self, line: &str, channel: &str) -> Result<()> {
        if let Some(substr_idx) = line.find(':') {
            // Client is setting the topic
            if substr_idx >= line.len() {
                return Err(Error::MalformedPacket)
            }

            let topic = &line[substr_idx + 1..];
            let chan_info = self.configured_chans.get_mut(channel).unwrap();
            chan_info.topic = Some(topic.to_string());

            let topic_reply =
                format!(":{}!anon@dark.fi TOPIC {} :{}\r\n", self.nickname, channel, topic);
            self.reply(&topic_reply).await?;
        } else {
            // Client is asking or the topic
            let chan_info = self.configured_chans.get(channel).unwrap();
            let topic_reply = if let Some(topic) = &chan_info.topic {
                format!("{} {} {} :{}\r\n", RPL_TOPIC, self.nickname, channel, topic)
            } else {
                const TOPIC: &str = "No topic is set";
                format!("{} {} {} :{}\r\n", RPL_NOTOPIC, self.nickname, channel, TOPIC)
            };
            self.reply(&topic_reply).await?;
        }
        Ok(())
    }

    async fn on_ping(&mut self, value: &str) -> Result<()> {
        let pong = format!("PONG {}\r\n", value);
        self.reply(&pong).await
    }

    async fn on_receive_cap(&mut self, line: &str, subcommand: &str) -> Result<()> {
        self.is_cap_end = false;

        let capabilities_keys: Vec<String> = self.capabilities.keys().cloned().collect();

        match subcommand {
            "LS" => {
                let cap_ls_reply = format!(
                    ":{}!anon@dark.fi CAP * LS :{}\r\n",
                    self.nickname,
                    capabilities_keys.join(" ")
                );
                self.reply(&cap_ls_reply).await?;
            }

            "REQ" => {
                let substr_idx = line.find(':').ok_or(Error::MalformedPacket)?;

                if substr_idx >= line.len() {
                    return Err(Error::MalformedPacket)
                }

                let cap: Vec<&str> = line[substr_idx + 1..].split(' ').collect();

                let mut ack_list = vec![];
                let mut nak_list = vec![];

                for c in cap {
                    if self.capabilities.contains_key(c) {
                        self.capabilities.insert(c.to_string(), true);
                        ack_list.push(c);
                    } else {
                        nak_list.push(c);
                    }
                }

                let cap_ack_reply = format!(
                    ":{}!anon@dark.fi CAP * ACK :{}\r\n",
                    self.nickname,
                    ack_list.join(" ")
                );

                let cap_nak_reply = format!(
                    ":{}!anon@dark.fi CAP * NAK :{}\r\n",
                    self.nickname,
                    nak_list.join(" ")
                );

                self.reply(&cap_ack_reply).await?;
                self.reply(&cap_nak_reply).await?;
            }

            "LIST" => {
                let enabled_capabilities: Vec<String> = self
                    .capabilities
                    .clone()
                    .into_iter()
                    .filter(|(_, v)| *v)
                    .map(|(k, _)| k)
                    .collect();

                let cap_list_reply = format!(
                    ":{}!anon@dark.fi CAP * LIST :{}\r\n",
                    self.nickname,
                    enabled_capabilities.join(" ")
                );
                self.reply(&cap_list_reply).await?;
            }

            "END" => {
                self.is_cap_end = true;
            }
            _ => {}
        }
        Ok(())
    }

    async fn on_receive_names(&mut self, channels: Vec<String>) -> Result<()> {
        for chan in channels.iter() {
            if !chan.starts_with('#') {
                continue
            }
            if self.configured_chans.contains_key(chan) {
                let chan_info = self.configured_chans.get(chan).unwrap();

                if chan_info.names.is_empty() {
                    return Ok(())
                }

                let names_reply = format!(
                    ":{}!anon@dark.fi {} = {} : {}\r\n",
                    self.nickname,
                    RPL_NAMEREPLY,
                    chan,
                    chan_info.names.join(" ")
                );

                self.reply(&names_reply).await?;

                let end_of_names = format!(
                    ":DarkFi {:03} {} {} :End of NAMES list\r\n",
                    RPL_ENDOFNAMES, self.nickname, chan
                );

                self.reply(&end_of_names).await?;
            }
        }
        Ok(())
    }

    async fn on_receive_privmsg(&mut self, line: &str, target: &str) -> Result<()> {
        let substr_idx = line.find(':').ok_or(Error::MalformedPacket)?;

        if substr_idx >= line.len() {
            return Err(Error::MalformedPacket)
        }

        let message = line[substr_idx + 1..].to_string();

        info!("[CLIENT {}] (Plain) PRIVMSG {} :{}", self.address, target, message,);

        let privmsgs_buffer = self.privmsgs_buffer.lock().await;
        let last_term = privmsgs_buffer.last_term() + 1;
        drop(privmsgs_buffer);

        let mut privmsg = Privmsg::new(&self.nickname, target, &message, last_term);

        if target.starts_with('#') {
            if !self.configured_chans.contains_key(target) {
                return Ok(())
            }

            let channel_info = self.configured_chans.get(target).unwrap();

            if !channel_info.joined {
                return Ok(())
            }

            if let Some(salt_box) = &channel_info.salt_box {
                encrypt_privmsg(salt_box, &mut privmsg);
                info!("[CLIENT {}] (Encrypted) PRIVMSG: {:?}", self.address, privmsg);
            }
        } else {
            if !self.configured_contacts.contains_key(target) {
                return Ok(())
            }

            let contact_info = self.configured_contacts.get(target).unwrap();
            if let Some(salt_box) = &contact_info.salt_box {
                encrypt_privmsg(salt_box, &mut privmsg);
                info!("[CLIENT {}] (Encrypted) PRIVMSG: {:?}", self.address, privmsg);
            }
        }

        {
            (*self.seen_msg_ids.lock().await).push(privmsg.id);
            (*self.privmsgs_buffer.lock().await).push(&privmsg)
        }

        self.p2p_notifiers
            .notify_with_exclude(privmsg.clone(), &[self.subscription.get_id()])
            .await;

        debug!(target: "ircd", "PRIVMSG to be sent: {:?}", privmsg);
        self.p2p.broadcast(privmsg).await?;

        Ok(())
    }

    async fn on_receive_join(&mut self, channels: Vec<String>) -> Result<()> {
        for chan in channels.iter() {
            if !chan.starts_with('#') {
                continue
            }
            if !self.configured_chans.contains_key(chan) {
                let mut chan_info = ChannelInfo::new()?;
                chan_info.topic = Some("n/a".to_string());
                self.configured_chans.insert(chan.to_string(), chan_info);
            }

            let chan_info = self.configured_chans.get_mut(chan).unwrap();
            if chan_info.joined {
                return Ok(())
            }
            chan_info.joined = true;

            let topic =
                if let Some(topic) = chan_info.topic.clone() { topic } else { "n/a".to_string() };
            chan_info.topic = Some(topic.to_string());

            {
                let j = format!(":{}!anon@dark.fi JOIN {}\r\n", self.nickname, chan);
                let t = format!(":DarkFi TOPIC {} :{}\r\n", chan, topic);
                self.reply(&j).await?;
                self.reply(&t).await?;
            }

            // Send messages in buffer
            if !self.capabilities.get("no-history").unwrap() {
                for msg in self.privmsgs_buffer.lock().await.iter() {
                    if msg.target == *chan {
                        self.p2p_notifiers
                            .notify_by_id(msg.clone(), self.subscription.get_id())
                            .await;
                    }
                }
            }
        }
        self.on_receive_names(channels).await?;
        Ok(())
    }
}

//
// Helper functions
//
fn clean_input_line(mut line: String) -> Result<String> {
    if line.is_empty() {
        return Err(Error::ChannelStopped)
    }

    if line == "\n" || line == "\r\n" {
        return Err(Error::ChannelStopped)
    }

    if &line[(line.len() - 2)..] == "\r\n" {
        // Remove CRLF
        line.pop();
        line.pop();
    } else if &line[(line.len() - 1)..] == "\n" {
        line.pop();
    } else {
        return Err(Error::ChannelStopped)
    }

    Ok(line.clone())
}

fn parse_line(line: &str) -> Result<(String, String)> {
    let mut tokens = line.split_ascii_whitespace();
    // Commands can begin with :garbage but we will reject clients doing
    // that for now to keep the protocol simple and focused.
    let command = tokens.next().ok_or(Error::MalformedPacket)?.to_uppercase();
    let value = tokens.next().ok_or(Error::MalformedPacket)?;
    Ok((command, value.to_owned()))
}