use anyhow::{anyhow, Result};
use log::{debug, error, info, warn};
use std::{
    fs::{File, OpenOptions},
    io::{Read, Write},
    str::from_utf8,
};

fn main() -> Result<()> {
    pretty_env_logger::try_init()?;
    let mut controller_data = [0; 4];

    let mut vblank = File::open("vblank")?;
    let mut input = OpenOptions::new().write(true).open("input")?;

    info!("ready");

    loop {
        let mut data = [0; 3];
        debug!("waiting for vblank");
        vblank.read(&mut data)?;
        let str = from_utf8(&data)?;
        debug!("got data: {}", str);

        match str {
            "OK\n" => input.write(&controller_data)?,
            "BYE" => {
                warn!("asked to exit by the game");
                return Ok(());
            },
            _ => {
                error!("got unknown FIFO data {}", str);
                return Err(anyhow!("unknown FIFO data received"));
            }
        };
    }
}