use clap::{Arg, App};
use qrcode::QrCode;

const C_W: char = ' ';
const C_B: char = '█';
const W: &str = " ";
const B: &str = " ";
const NL: &str = "\n";

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let matches = App::new("QR cli")
                    .version("0.1.1")
                    .author("Hatter Jiang <jht5945@gmail.com>")
                    .about("QR command line tool")
                    .arg(Arg::with_name("INPUT")
                        .help("Set the QR input")
                        .required(true)
                        .index(1))
                    .get_matches();

    let mut input: Option<String> = None;
    if let Some(input_arg) = matches.args.get("INPUT") {
        if input_arg.vals.len() > 0 {
            input = input_arg.vals[0].clone().into_string().ok();
        }
    }

    let input_string = match input {
        Some(i) => i,
        None => return Ok(()), // TODO no input
    };

    let code = QrCode::new(input_string.as_bytes()).unwrap();
    let string = code.render::<char>()
        .quiet_zone(false)
        .module_dimensions(2, 1)
        .build();
    let mut output_stirng = String::with_capacity(1024);
    let mut ln_len = 0;
    for c in string.chars() {
        match c {
            C_B | C_W => ln_len += 1,
            _ => break,
        }
    }
    println!("【QR test for: {}】", &input_string);
    for _ in 0..ln_len+4 {
        output_stirng.push_str(W);
    }
    output_stirng.push_str(NL);
    output_stirng.push_str(W);
    output_stirng.push_str(W);
    for c in string.chars() {
        match c {
            C_B => output_stirng.push_str(B),
            C_W => output_stirng.push_str(W),
            _ => { // new line
                output_stirng.push_str(W);
                output_stirng.push_str(W);
                output_stirng.push(c);
                output_stirng.push_str(W);
                output_stirng.push_str(W);
            }
        }
    }
    output_stirng.push_str(W);
    output_stirng.push_str(W);
    output_stirng.push_str(NL);
    for _ in 0..ln_len+4 {
        output_stirng.push_str(W);
    }
    println!("{}", output_stirng);

    Ok(())
}