use std::io;
use rand::Rng;
use std::cmp::Ordering;

fn main() {
    println!("Guess the number!");

    // generate random number from 1 to 100
    let secret_number = rand::thread_rng().gen_range(1..=100);

    loop {
        println!("Please input your guess.");

        // create an empty growable String object
        let mut guess = String::new();

        // read user input
        io::stdin()
            .read_line(&mut guess)
            .expect("Failed to read line");

        // if input valid, convert it from String to u32
        let guess: u32 = match guess.trim().parse() {
            Ok(num) => num,
            Err(_) => {
                println!("Invalid input.");
                continue;
            }
        };
        
        println!("You guessed: {guess}");
        
        // compare guess with secret_number
        match guess.cmp(&secret_number) {
            Ordering::Less => println!("Too small!"),
            Ordering::Greater => println!("Too big!"),
            Ordering::Equal => {
                println!("You win!");
                break;
            }
        }
    }
}