triagebot/parser/src/command.rs

use crate::code_block::ColorCodeBlocks;
use crate::error::Error;
use crate::token::{Token, Tokenizer};

pub mod assign;
pub mod nominate;
pub mod ping;
pub mod relabel;

pub fn find_commmand_start(input: &str, bot: &str) -> Option<usize> {
    input.find(&format!("@{}", bot))
}

#[derive(Debug)]
pub enum Command<'a> {
    Relabel(Result<relabel::RelabelCommand, Error<'a>>),
    Assign(Result<assign::AssignCommand, Error<'a>>),
    Ping(Result<ping::PingCommand, Error<'a>>),
    Nominate(Result<nominate::NominateCommand, Error<'a>>),
    None,
}

#[derive(Debug)]
pub struct Input<'a> {
    all: &'a str,
    parsed: usize,
    code: ColorCodeBlocks,
    bot: &'a str,
}

fn parse_single_command<'a, T, F, M>(
    parse: F,
    mapper: M,
    tokenizer: &Tokenizer<'a>,
) -> Option<(Tokenizer<'a>, Command<'a>)>
where
    F: FnOnce(&mut Tokenizer<'a>) -> Result<Option<T>, Error<'a>>,
    M: FnOnce(Result<T, Error<'a>>) -> Command<'a>,
    T: std::fmt::Debug,
{
    let mut tok = tokenizer.clone();
    let res = parse(&mut tok);
    log::info!("parsed {:?} command: {:?}", std::any::type_name::<T>(), res);
    match res {
        Ok(None) => None,
        Ok(Some(v)) => Some((tok, mapper(Ok(v)))),
        Err(err) => Some((tok, mapper(Err(err)))),
    }
}

impl<'a> Input<'a> {
    pub fn new(input: &'a str, bot: &'a str) -> Input<'a> {
        Input {
            all: input,
            parsed: 0,
            code: ColorCodeBlocks::new(input),
            bot,
        }
    }

    pub fn parse_command(&mut self) -> Command<'a> {
        let start = match find_commmand_start(&self.all[self.parsed..], self.bot) {
            Some(pos) => pos,
            None => return Command::None,
        };
        self.parsed += start;
        let mut tok = Tokenizer::new(&self.all[self.parsed..]);
        assert_eq!(
            tok.next_token().unwrap(),
            Some(Token::Word(&format!("@{}", self.bot)))
        );
        log::info!("identified potential command");

        let mut success = vec![];

        let original_tokenizer = tok.clone();

        success.extend(parse_single_command(
            relabel::RelabelCommand::parse,
            Command::Relabel,
            &original_tokenizer,
        ));
        success.extend(parse_single_command(
            assign::AssignCommand::parse,
            Command::Assign,
            &original_tokenizer,
        ));
        success.extend(parse_single_command(
            ping::PingCommand::parse,
            Command::Ping,
            &original_tokenizer,
        ));
        success.extend(parse_single_command(
            nominate::NominateCommand::parse,
            Command::Nominate,
            &original_tokenizer,
        ));

        if success.len() > 1 {
            panic!(
                "succeeded parsing {:?} to multiple commands: {:?}",
                &self.all[self.parsed..],
                success
            );
        }

        if self
            .code
            .overlaps_code((self.parsed)..(self.parsed + tok.position()))
            .is_some()
        {
            log::info!("command overlaps code; code: {:?}", self.code);
            return Command::None;
        }

        match success.pop() {
            Some((mut tok, c)) => {
                // if we errored out while parsing the command do not move the input forwards
                if c.is_ok() {
                    self.parsed += tok.position();
                }
                c
            }
            None => Command::None,
        }
    }
}

impl<'a> Command<'a> {
    pub fn is_ok(&self) -> bool {
        match self {
            Command::Relabel(r) => r.is_ok(),
            Command::Assign(r) => r.is_ok(),
            Command::Ping(r) => r.is_ok(),
            Command::Nominate(r) => r.is_ok(),
            Command::None => true,
        }
    }

    pub fn is_err(&self) -> bool {
        !self.is_ok()
    }

    pub fn is_none(&self) -> bool {
        match self {
            Command::None => true,
            _ => false,
        }
    }
}

#[test]
fn errors_outside_command_are_fine() {
    let input =
        "haha\" unterminated quotes @bot modify labels: +bug. Terminating after the command";
    let mut input = Input::new(input, "bot");
    assert!(input.parse_command().is_ok());
}

#[test]
fn code_1() {
    let input = "`@bot modify labels: +bug.`";
    let mut input = Input::new(input, "bot");
    assert!(input.parse_command().is_none());
}

#[test]
fn code_2() {
    let input = "```
    @bot modify labels: +bug.
    ```";
    let mut input = Input::new(input, "bot");
    assert!(input.parse_command().is_none());
}

#[test]
fn move_input_along() {
    let input = "@bot modify labels: +bug. Afterwards, delete the world.";
    let mut input = Input::new(input, "bot");
    let parsed = input.parse_command();
    assert!(parsed.is_ok());
    assert_eq!(&input.all[input.parsed..], " Afterwards, delete the world.");
}

#[test]
fn move_input_along_1() {
    let input = "@bot modify labels\": +bug. Afterwards, delete the world.";
    let mut input = Input::new(input, "bot");
    assert!(input.parse_command().is_err());
    // don't move input along if parsing the command fails
    assert_eq!(input.parsed, 0);
}