use rand::Rng;
use std::io::{stdin,stdout,Write};

fn write_map(snake: char, apple: char, x_snake: u16, y_snake: u16, x_apple: u16, y_apple: u16, width: u16, height: u16) {
    print!("{}[2J", 27 as char);
    for y in 0..height {
        for x in 0..width {
            if x == x_snake && y == y_snake {
                print!("{}",snake);
            }
            else if x == x_apple && y == y_apple {
                print!("{}", apple);
            }
            else {
                print!(".");
            }
        }
        println!();
    }
    println!("Snake: {},{}\nApple: {},{}",x_snake,y_snake,x_apple,y_apple)
}

fn input() -> String{
    let mut s=String::new();
    let _=stdout().flush();
    stdin().read_line(&mut s).expect("Did not enter a correct string");
    if let Some('\n')=s.chars().next_back() {
        s.pop();
    }
    if let Some('\r')=s.chars().next_back() {
        s.pop();
    }
    return s;
}

fn main() {
    let mut rng = rand::thread_rng();

    let width: u16 = 130;
    let height: u16 = 30;

    let mut x_snake: u16 = 0;
    let mut y_snake: u16 = 0;
    let mut x_apple: u16 = rand::thread_rng().gen_range(0..width);
    let mut y_apple: u16 = rand::thread_rng().gen_range(0..height);
    println!("X apple: {}, Y apple: {}",x_apple,y_apple);

    let snake: char = 'S';
    let apple: char = 'A';

    let mut alive: bool = true; 

    write_map(snake, apple, x_snake, y_snake, x_apple, y_apple, width, height);
    while alive {
        let direction: &str = &input();    
        // Movement
        if direction == "w" { 
            if y_snake == 0 { y_snake = height - 1 }
            else { y_snake-=1 } 
        }
        if direction == "a" { 
            if x_snake == 0 { x_snake = width - 1 }
            else { x_snake-=1 }
        }
        if direction == "s" { y_snake+=1 }
        if direction == "d" { x_snake+=1 }
        // Looping over edge
        if x_snake > width { x_snake = 0 }
        if x_snake < 0 { x_snake = width }
        write_map(snake, apple, x_snake, y_snake, x_apple, y_apple, width, height);
    };
}