rand_string 0.1.1

use rand::seq::SliceRandom;
use std::string::FromUtf8Error;

const BASE_STR: &str = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!@#$%^";

fn gen_string(size: usize) -> Result<String, FromUtf8Error> {
    let mut rng = &mut rand::thread_rng();
    let s = String::from_utf8(
        BASE_STR
            .as_bytes()
            .choose_multiple(&mut rng, size)
            .cloned()
            .collect(),
    )?;
    Ok(s)
}

pub fn gen_rand_string(size: usize) -> Option<String> {
    if size > 0 {
        match gen_string(size) {
            Ok(s) => Some(s),
            _ => None,
        }
    } else {
        panic!("Interger must be greater than 0");
    }
}