tiny_terminal_snake/
snake.rs

1use crate::frame::*;
2use std::io::{Error, ErrorKind, Result};
3
4#[derive(Copy, Clone, Debug)]
5pub enum Direction {
6    Up,
7    Down,
8    Left,
9    Right,
10}
11
12#[derive(Debug)]
13pub struct Snake {
14    pub body: Vec<(i32, i32)>,
15    dir: Direction,
16}
17
18impl Snake {
19    pub fn new(head: (i32, i32), dir: Direction, length: usize) -> Self {
20        let a = match dir {
21            Direction::Up => (-1, 0),
22            Direction::Down => (1, 0),
23            Direction::Left => (0, 1),
24            Direction::Right => (0, -1),
25        };
26
27        // make tail
28        let b = (0..length)
29            .map(|x| (head.0 + x as i32 * a.0, head.1 + x as i32 * a.1))
30            .collect::<Vec<_>>();
31
32        if !b.iter().all(|x| x.0 >= 0 && x.1 >= 0) {
33            return Self { body: vec![], dir };
34        }
35
36        Self {
37            body: b.iter().map(|x| (x.0, x.1)).collect::<Vec<_>>(),
38            dir,
39        }
40    }
41
42    pub fn len(&self) -> usize {
43        self.body.len()
44    }
45
46    pub fn head(&self) -> (i32, i32) {
47        self.body.first().unwrap().clone()
48    }
49
50    pub fn add_tail(&mut self, d: (i32, i32)) {
51        self.body.push(d);
52    }
53
54    pub fn show(&self, frame: &mut Frame) -> Result<()> {
55        for b in &self.body {
56            frame.write(b.0, b.1, String::from("◼"))?;
57        }
58        Ok(())
59    }
60
61    // return the tail
62    pub fn move_one_step(&mut self, k: &Direction) -> Result<(i32, i32)> {
63        self.dir = *k;
64        let step = match self.dir {
65            Direction::Up => (-1, 0),
66            Direction::Down => (1, 0),
67            Direction::Left => (0, -1),
68            Direction::Right => (0, 1),
69        };
70
71        let tail = self.body.pop().unwrap();
72        let a = self.body.first().unwrap();
73        let new_head = (a.0 as i32 + step.0, a.1 as i32 + step.1);
74
75        if self.included(&(new_head.0 as usize, new_head.1 as usize)) {
76            return Err(Error::new(ErrorKind::AlreadyExists, ""));
77        }
78
79        self.body.insert(0, new_head);
80
81        Ok(tail)
82    }
83
84    pub fn included(&self, point: &(usize, usize)) -> bool {
85        self.body.contains(&(point.0 as i32, point.1 as i32))
86    }
87}
tiny_terminal_snake/snake.rs

tiny_terminal_snake/
snake.rs
