matrix-bot/src/main.rs

#![warn(clippy::nursery, clippy::pedantic)]

use std::fmt::Display;
use std::path::PathBuf;
use std::str::FromStr;
use std::time::Duration;

use clap::Parser;
use enum_iterator::IntoEnumIterator;
use matrix_sdk::room::{Joined, Room};
use matrix_sdk::ruma::events::room::member::MemberEventContent;
use matrix_sdk::ruma::events::room::message::{
    MessageEventContent, MessageType, TextMessageEventContent,
};
use matrix_sdk::ruma::events::{StrippedStateEvent, SyncMessageEvent};
use matrix_sdk::ruma::UserId;
use matrix_sdk::{Client, ClientConfig, Result, Session, SyncSettings};
use serde::{Deserialize, Serialize};
use tracing::{error, info};

#[derive(Parser)]
struct Args {
    #[clap(subcommand)]
    subcommand: Command,
}

#[derive(Parser)]
enum Command {
    Login {
        user_id: UserId,
        password: String,
    },
    Run {
        #[clap(default_value = "config.toml")]
        config_path: PathBuf,
        #[clap(default_value = "data")]
        store_path: PathBuf,
    },
}

#[derive(Serialize, Deserialize)]
struct TomlConfig {
    session: Session,
}

#[tokio::main]
async fn main() -> Result<()> {
    tracing_subscriber::fmt::init();
    let args = Args::parse();

    match args.subcommand {
        Command::Login { user_id, password } => handle_login(user_id, &password).await,
        Command::Run {
            config_path,
            store_path,
        } => handle_run(config_path, store_path).await,
    }
}

async fn handle_login(user_id: UserId, password: &str) -> Result<()> {
    let client = Client::new_from_user_id(user_id.clone()).await?;
    let resp = client
        .login(user_id.localpart(), password, None, None)
        .await?;

    info!("Config generated. Please store this somewhere (like config.toml)!");
    println!(
        "\n\n{}",
        toml::to_string_pretty(&TomlConfig {
            session: Session {
                access_token: resp.access_token,
                device_id: resp.device_id,
                user_id,
            }
        })
        .unwrap()
    );

    Ok(())
}

async fn handle_run(config_path: PathBuf, store_path: PathBuf) -> Result<()> {
    let data = std::fs::read_to_string(config_path)?;
    let config: TomlConfig = toml::from_str(&data).unwrap();

    let client_config = ClientConfig::default().store_path(store_path);
    let client =
        Client::new_from_user_id_with_config(config.session.user_id.clone(), client_config).await?;
    client.restore_login(config.session.clone()).await?;

    info!(user = %config.session.user_id, device_id = %config.session.device_id, "Logged in");

    let sync_settings = SyncSettings::default();

    // Sync once before registering events to not double-send events on boot.
    client.sync_once(sync_settings.clone()).await?;

    client
        .register_event_handler(auto_join)
        .await
        .register_event_handler(on_room_message)
        .await;

    // Syncing is important to synchronize the client state with the server.
    // This method will never return.
    client.sync(sync_settings).await;

    Ok(())
}

async fn auto_join(
    room_member: StrippedStateEvent<MemberEventContent>,
    client: Client,
    room: Room,
) -> Result<()> {
    if room_member.state_key != client.user_id().await.unwrap() {
        return Ok(());
    }

    if let Room::Invited(room) = room {
        info!("Autojoining room {}", room.room_id());
        let mut delay = 2;

        while let Err(err) = room.accept_invitation().await {
            // retry autojoin due to synapse sending invites, before the
            // invited user can join for more information see
            // https://github.com/matrix-org/synapse/issues/4345
            error!(
                room_id = ?room.room_id(),
                ?err,
                "Failed to join room, retrying in {delay}s",
            );

            tokio::time::sleep(Duration::from_secs(delay)).await;
            delay *= 2;

            if delay > 3600 {
                error!(
                    room_id = ?room.room_id(),
                    ?err,
                    "Failed to join room. Giving up.",
                );
                break;
            }
        }

        info!(room_id = ?room.room_id(), "Successfully joined room.");
    }

    Ok(())
}

async fn on_room_message(
    event: SyncMessageEvent<MessageEventContent>,
    room: Room,
    client: Client,
) -> Result<()> {
    // Ignore messages sent from self.
    if client.user_id().await.as_ref() == Some(&event.sender) {
        return Ok(());
    }

    if let Room::Joined(room) = room {
        parse_message(event, room).await?;
    }

    Ok(())
}

async fn parse_message(event: SyncMessageEvent<MessageEventContent>, room: Joined) -> Result<()> {
    let message = match &event.content.msgtype {
        MessageType::Text(TextMessageEventContent { body, .. }) => body.clone(),
        _ => return Ok(()),
    };

    if let Some(message) = message.strip_prefix('!') {
        let (command, args) = message.split_once(' ').unwrap_or((message, ""));
        match BotCommand::from_str(command).ok() {
            Some(BotCommand::Source) => source(room).await?,
            Some(BotCommand::Uwu) => uwuify(room, args).await?,
            Some(BotCommand::Ping) => ping(room).await?,
            Some(BotCommand::Help) => help(room).await?,
            _ => unsupported_command(event, room, command).await?,
        }
    }

    Ok(())
}

#[derive(enum_iterator::IntoEnumIterator)]
enum BotCommand {
    Help,
    Source,
    Uwu,
    Ping,
}

impl BotCommand {
    const fn help_text(&self) -> &'static str {
        match self {
            Self::Source => "Links to the source code for this bot.",
            Self::Uwu => "Uwuifies your message.",
            Self::Ping => "Pong!",
            Self::Help => "Prints this help.",
        }
    }
}

impl FromStr for BotCommand {
    type Err = ();

    fn from_str(s: &str) -> std::result::Result<Self, Self::Err> {
        match s.to_lowercase().as_str() {
            "source" => Ok(Self::Source),
            "uwu" => Ok(Self::Uwu),
            "ping" => Ok(Self::Ping),
            "help" => Ok(Self::Help),
            _ => Err(()),
        }
    }
}

impl Display for BotCommand {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            BotCommand::Source => write!(f, "source"),
            BotCommand::Uwu => write!(f, "uwu"),
            BotCommand::Ping => write!(f, "ping"),
            BotCommand::Help => write!(f, "help"),
        }
    }
}

async fn source(room: Joined) -> Result<()> {
    let content = MessageEventContent::text_plain("https://git.eddie.sh/edward/matrix-bot");
    room.send(content, None).await?;
    Ok(())
}

async fn uwuify(room: Joined, message: &str) -> Result<()> {
    let message = if message.is_empty() {
        "uwu".to_owned()
    } else {
        uwuifier::uwuify_str_sse(message)
    };
    let content = MessageEventContent::text_plain(message);
    room.send(content, None).await?;
    Ok(())
}

async fn ping(room: Joined) -> Result<()> {
    let content = MessageEventContent::text_plain("Pong!");
    room.send(content, None).await?;
    Ok(())
}

async fn help(room: Joined) -> Result<()> {
    let mut msg = "List of commands:\n\n".to_owned();
    for command in BotCommand::into_enum_iter() {
        msg.push_str(&command.to_string());
        msg.push_str(" - ");
        msg.push_str(command.help_text());
        msg.push_str("\n");
    }
    let content = MessageEventContent::notice_plain(msg);
    room.send(content, None).await?;
    Ok(())
}

async fn unsupported_command(
    original_event: SyncMessageEvent<MessageEventContent>,
    room: Joined,
    command: &str,
) -> Result<()> {
    let resp = original_event.into_full_event(room.room_id().clone());
    let content =
        MessageEventContent::notice_reply_plain(format!("Unknown command `{command}`"), &resp);
    room.send(content, None).await?;
    Ok(())
}