rulebot/src/main.rs

use rand::Rng;

type State = [bool; 8];

fn map_state(rule: u8, state: &State) -> State {
    let mut new_state: [bool; 8] = [false; 8];

    for i in 0..8 {
        let pattern = ((i != 0 && state[i - 1]) as u8 * 4)
            | (state[i] as u8 * 2)
            | ((i != 7 && state[i + 1]) as u8);
        new_state[i] = (rule >> pattern & 1) == 1;
    }

    new_state
}

fn state_to_string(state: State) -> String {
    state.map(|c| if c { "⬛" } else { "⬜" }).concat()
}

fn num_to_state(num: u8) -> State {
    let mut state = [false; 8];

    for i in 0..8 {
        state[i] = (num >> i & 1) == 1;
    }

    state
}

fn main() {
    let mut rng = rand::thread_rng();
    let seed: u16 = rng.gen();

    let rule: u8 = (seed & 0xff) as u8;
    let init_state = num_to_state((seed >> 8 & 0xff) as u8);

    let states: String = (0..8)
        .scan(init_state, |state, _i| {
            let old_state = *state;
            *state = map_state(rule, state);
            Some(old_state)
        })
        .map(state_to_string)
        .collect::<Vec<String>>()
        .join("\n");

    println!("Rule: {}\n{}", rule, states);

    let client = reqwest::blocking::Client::new();
    let res = client
        .post("https://mastodon.raptorpond.com/api/v1/statuses")
        .header(
            "Authorization",
            format!("Bearer {}", std::env::var("MASTODON_TOKEN").unwrap()),
        )
        .form(&[
            ("status", format!("Rule: {}\n{}", rule, states)),
            ("visibility", String::from("private")),
        ])
        .send();

    match res {
        Ok(_) => std::process::exit(exitcode::OK),
        Err(error) => {
            println!("{:?}", error);
            std::process::exit(exitcode::IOERR);
        }
    }
}