use std::{io::Write, path::PathBuf};

use clap::Parser;

#[derive(Debug, Parser)]
struct Args {
    file: Option<String>,
}

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let stdout = std::io::stdout();
    let handle = stdout.lock();
    let mut writer = std::io::BufWriter::new(handle);

    let args = Args::parse();
    let mut reader = match args.file {
        Some(file) => {
            let path = PathBuf::from(file);
            let file = std::fs::File::open(path)?;
            Box::new(std::io::BufReader::new(file)) as Box<dyn std::io::Read>
        }
        None => Box::new(std::io::BufReader::new(std::io::stdin())) as Box<dyn std::io::Read>,
    };

    let mut buf = [0u8; 1024];
    write!(writer, "[")?;
    loop {
        let n = reader.read(&mut buf)?;
        if n == 0 {
            break;
        }
        for i in 0..n {
            write!(writer, "{:#02X},", buf[i])?;
        }
    }
    write!(writer, "];")?;
    writer.flush()?;
    Ok(())
}