nix-files/pkgs/additional/mx-sanebot/src/msg_handler.rs

309 lines
8.5 KiB
Rust

use std::borrow::ToOwned;
use std::fmt;
use std::process;
use std::str;
use serde_json;
use serde::Deserialize;
use super::parsing::{self, Parser};
mod tt {
pub(super) use super::parsing::{
Either,
Lit,
Maybe,
Nul,
OneOrMore,
Then,
};
use crate::{ilit, lit};
// grammar:
// REQUEST = <!> (HELP | BT-REQ)
//
// HELP = <help>
// BT-REQ = <bt> [(BT-SEARCH | BT-ADD)]
//
// BT-SEARCH = <search> ARGS
// BT-ADD = <add> ARGS
//
// MAYBE_ARGS = [SPACE [ARGS]]
// ARGS = ARG MAYBE_ARGS
// ARG = NOT-SPACE [ARG]
//
// NOT-SPACE = (ALPHA | NUM | SPECIAL)
pub(super) type Request = Then<Bang, Either<Help, BtReq>>;
pub(super) type Bang = Lit<{ '!' as u8 }>;
pub(super) type Space = Lit<{ ' ' as u8 }>;
pub(super) type Alpha = Either<
ilit!('A'), Either<
ilit!('B'), Either<
ilit!('C'), Either<
ilit!('D'), Either<
ilit!('E'), Either<
ilit!('F'), Either<
ilit!('G'), Either<
ilit!('H'), Either<
ilit!('I'), Either<
ilit!('J'), Either<
ilit!('K'), Either<
ilit!('L'), Either<
ilit!('M'), Either<
ilit!('N'), Either<
ilit!('O'), Either<
ilit!('P'), Either<
ilit!('Q'), Either<
ilit!('R'), Either<
ilit!('S'), Either<
ilit!('T'), Either<
ilit!('U'), Either<
ilit!('V'), Either<
ilit!('W'), Either<
ilit!('X'), Either<
ilit!('Y'),
ilit!('Z'),
>>>>>>>>>>>>>>>>>>>>>>>>>;
pub(super) type Dig = Either<
lit!('0'), Either<
lit!('1'), Either<
lit!('2'), Either<
lit!('3'), Either<
lit!('4'), Either<
lit!('5'), Either<
lit!('6'), Either<
lit!('7'), Either<
lit!('8'),
lit!('9'),
>>>>>>>>>;
pub(super) type Symbol = Either<
Bang, Either<
lit!('@'), Either<
lit!('#'), Either<
lit!('$'), Either<
lit!('%'), Either<
lit!('^'), Either<
lit!('&'), Either<
lit!('*'), Either<
lit!('('), Either<
lit!(')'), Either<
lit!('-'), Either<
lit!('_'), Either<
lit!('+'), Either<
lit!('='), Either<
lit!('['), Either<
lit!('{'), Either<
lit!(']'), Either<
lit!('}'), Either<
lit!('\\'), Either<
lit!('|'), Either<
lit!(';'), Either<
lit!(':'), Either<
lit!('\''), Either<
lit!('"'), Either<
lit!(','), Either<
lit!('<'), Either<
lit!('.'), Either<
lit!('>'), Either<
lit!('/'), Either<
lit!('?'), Either<
lit!('`'),
lit!('~'),
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>;
// pub(super) type Whitespace = Then<Space, Maybe<Box<Whitespace>>>;
pub(super) type Whitespace = OneOrMore<Space>;
pub(super) type Help = Then<
ilit!('H'), Then<
ilit!('E'), Then<
ilit!('L'),
ilit!('P'),
>>>;
pub(super) type BtReq = Then<Bt, Maybe<Then<Whitespace, BtSearch>>>;
pub(super) type Bt = Then<
ilit!('B'),
ilit!('T'),
>;
pub(super) type BtSearch = Then<Search, OneOrMore<SpacedArg>>;
pub(super) type Search = Then<
ilit!('S'), Then<
ilit!('E'), Then<
ilit!('A'), Then<
ilit!('R'), Then<
ilit!('C'),
ilit!('H'),
>>>>>;
pub(super) type SpacedArg = Then<Whitespace, Arg>;
pub(super) type Arg = OneOrMore<Either<
Alpha, Either<
Dig,
Symbol
>>>;
}
pub struct MessageHandler;
impl MessageHandler {
/// parse any message directed to me, and return text to present to the user who messaged me.
/// the message passed here may or may not be a "valid" request.
/// if invalid, expect an error message or help message, still meant for the user.
pub fn on_msg(&self, msg: &str) -> Response {
let req = self.parse_msg(msg).unwrap_or(Request::Help);
req.evaluate()
}
fn parse_msg(&self, msg: &str) -> Result<Request, ()> {
match msg.as_bytes().parse_all::<tt::Request>() {
Ok(req) => Ok(req.into()),
Err(_) => Err(()),
}
}
}
enum Request {
Help,
Bt,
BtSearch(String),
}
impl From<tt::Request> for Request {
fn from(t: tt::Request) -> Self {
match t {
tt::Then(_bang, tt::Either::A(_help)) => Self::Help,
tt::Then(_bang, tt::Either::B(bt_req)) => match bt_req {
tt::Then(_bt, tt::Either::A(tt::Then(_ws, bt_search))) => {
let tt::Then(_, spaced_args) = bt_search;
Self::BtSearch(spaced_args.to_string())
},
tt::Then(_bt, tt::Either::B(tt::Nul)) => Self::Bt,
}
}
}
}
fn exec_stdout(program: &str, args: &[&str]) -> Option<String> {
process::Command::new(program)
.args(args)
.output()
.ok()
.and_then(|output|
str::from_utf8(&output.stdout).ok().map(ToOwned::to_owned)
)
}
impl Request {
fn evaluate(self) -> Response {
match self {
Request::Help => Response::Help,
Request::Bt => match exec_stdout("sane-bt-show", &[]) {
Some(m) => Response::Bt(m),
None => Response::Error("failed to execute sane-bt-show".to_owned()),
},
Request::BtSearch(phrase) => match exec_stdout("sane-bt-search", &[&*phrase, "--json"]) {
Some(r) => match serde_json::from_str(&r) {
Ok(torrents) => Response::BtSearch(torrents),
Err(e) => Response::Error(format!("failed to decode sane-bt-search response: {e}")),
},
None => Response::Error("failed to execute sane-bt-search".to_owned()),
},
}
}
}
#[derive(Deserialize)]
pub struct Torrent {
seeders: u32,
pub_date: String, // YYYY-MM-DD
size: u64,
tracker: String,
title: String,
magnet: String,
}
pub enum Response {
Error(String),
Help,
Bt(String),
BtSearch(Vec<Torrent>),
}
impl Response {
pub fn html(&self) -> Option<String> {
match self {
Response::Help => Some(
r#"
commands:
<ul>
<li><code>!help</code> => show this message</li>
<li><code>!bt</code> => show torrent statuses</li>
<li><code>!bt search &lt;phrase&gt;</code> => search for torrents</li>
</ul>
"#.to_owned()
),
Response::BtSearch(torrents) => Some({
let fmt_torrents = torrents.into_iter().map(|t| {
let Torrent {
seeders,
pub_date,
size,
tracker,
title,
magnet,
} = t;
let mib = size >> 20;
format!(r#"
<tr>
<th>{seeders}</th>
<th>{pub_date}</th>
<th>{mib}</th>
<th>{tracker}</th>
<th>{title}</th>
<th>{magnet}</th>
</tr>
"#)
}).collect::<String>();
format!(r#"
<table>
<tr>
<th>Seeders</th>
<th>Date</th>
<th>Size (MiB)</th>
<th>Tracker</th>
<th>Title</th>
<th>URL</th>
</tr>
{fmt_torrents}
</table>
"#)
}),
_ => None,
}
}
}
impl fmt::Display for Response {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
Response::Error(e) => write!(f, "{}", e)?,
Response::Help => {
write!(f, "commands:\n")?;
write!(f, " !help => show this message\n")?;
write!(f, " !bt => show torrent statuses\n")?;
write!(f, " !bt search <phrase> => search for torrents\n")?;
},
Response::Bt(stdout) => write!(f, "{}", stdout)?,
Response::BtSearch(torrents) => write!(f, "{} torrents", torrents.len())?,
}
Ok(())
}
}