use clap::{Arg, Command};
use std::io::{BufRead, Read, Write};
use stream_vbyte::{decode::decode, encode::encode, scalar::Scalar};

fn main() {
    let matches = Command::new("stream-vbyte cli")
        .subcommand(Command::new("enc").about("Encode numbers"))
        .subcommand(
            Command::new("dec").about("Decode numbers").arg(
                Arg::new("count")
                    .help("count of numbers in encoded input")
                    .short('c')
                    .long("count")
                    .required(true),
            ),
        )
        .get_matches();

    match matches.subcommand_name() {
        Some("enc") => run_encode(),
        Some("dec") => {
            let count: usize = matches
                .subcommand_matches("dec")
                .unwrap()
                .get_one::<String>("count")
                .unwrap()
                .parse()
                .expect("count must be an int");

            run_decode(count);
        }
        _ => println!("Invalid subcommand"),
    }
}

fn run_encode() {
    let stdin = std::io::stdin();
    let stdin_handle = stdin.lock();

    let nums: Vec<u32> = stdin_handle
        .lines()
        .map(|l| l.expect("Should be able to read stdin"))
        .map(|s| s.parse().expect("Each line must be a u32"))
        .collect();

    let mut encoded = Vec::new();
    encoded.resize(nums.len() * 5, 0);
    let encoded_len = encode::<Scalar>(&nums, &mut encoded);

    let stdout = std::io::stdout();
    let mut stdout_handle = stdout.lock();
    stdout_handle
        .write_all(&encoded[0..encoded_len])
        .expect("Should be able to write to stdout");

    eprintln!("Encoded {} numbers", nums.len());
}

fn run_decode(count: usize) {
    let stdin = std::io::stdin();
    let mut stdin_handle = stdin.lock();

    let mut encoded = Vec::new();
    stdin_handle
        .read_to_end(&mut encoded)
        .expect("Should be able to read stdin");

    let mut decoded = Vec::new();
    decoded.resize(count, 0);
    decode::<Scalar>(&encoded, count, &mut decoded);

    for d in &decoded {
        println!("{}", d);
    }

    eprintln!("Decoded {} numbers", decoded.len());
}