commit c5d1d1dfbfca853a84003fa373c651393f8255eb
Author: Augusto Gunsch <augustogunsch@tutanota.com>
Date:   Sun Nov 28 23:00:39 2021 -0300

    Initial commit

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..27aff38
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+/target
+*.lock
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..9515810
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,11 @@
+[package]
+name = "snakers"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+tui = "0.16"
+termion = "1.5"
+rand = "0.8.4"
diff --git a/src/event.rs b/src/event.rs
new file mode 100644
index 0000000..7497841
--- /dev/null
+++ b/src/event.rs
@@ -0,0 +1,49 @@
+use std::io;
+use std::thread;
+use std::sync::mpsc;
+use termion::input::TermRead;
+use termion::event::Key;
+
+pub struct Events {
+    rx: mpsc::Receiver<Key>,
+}
+
+impl Events {
+    pub fn new() -> Events {
+        let (tx, rx) = mpsc::channel();
+
+        thread::spawn(move || {
+            let stdin = io::stdin();
+
+            for key in stdin.keys() {
+                match key {
+                    Ok(key) => if let Err(_) = tx.send(key) { return; },
+                    Err(_) => panic!("Failed to read stdin"),
+                }
+            }
+        });
+
+        Events {
+            rx,
+        }
+    }
+
+    pub fn next(&self) -> Option<Key> {
+        let key = self.rx.try_recv();
+        match key {
+            Ok(key) => Some(key),
+            Err(err) => match err {
+                mpsc::TryRecvError::Empty => None,
+                _ => panic!("Channel closed")
+            },
+        }
+    }
+
+    pub fn last(&self) -> Option<Key> {
+        let mut key = self.next();
+        while let Some(k) = self.next() {
+            key = Some(k);
+        }
+        key
+    }
+}
diff --git a/src/food.rs b/src/food.rs
new file mode 100644
index 0000000..f161789
--- /dev/null
+++ b/src/food.rs
@@ -0,0 +1,49 @@
+use crate::vec2::Vec2;
+use rand::prelude::*;
+use tui::widgets::canvas::{Context};
+use tui::style::Color;
+
+use crate::SCREEN_WIDTH;
+use crate::SCREEN_HEIGHT;
+
+pub struct Food {
+    pos: Vec2,
+    spoil_in: i32,
+}
+
+impl Food {
+    pub fn draw(&self, ctx: &mut Context) {
+        if self.spoiled() {
+            ctx.print(self.pos.x, self.pos.y, "*", Color::Green);
+        } else {
+            ctx.print(self.pos.x, self.pos.y, "*", Color::Red);
+        }
+    }
+
+    pub fn new() -> Self {
+        let mut rng = thread_rng();
+        let x = rng.gen_range(-(SCREEN_WIDTH/2.0) as i32..(SCREEN_WIDTH/2.0) as i32);
+        let y = rng.gen_range(-(SCREEN_HEIGHT/2.0) as i32..(SCREEN_HEIGHT/2.0) as i32);
+
+        Self {
+            pos: Vec2::new(x as f64, y as f64),
+            spoil_in: rng.gen_range(50..300),
+        }
+    }
+
+    pub fn spoiled(&self) -> bool {
+        self.spoil_in >= 0
+    }
+
+    pub fn rotten(&self) -> bool {
+        self.spoil_in <= -100
+    }
+
+    pub fn tick_spoil(&mut self) {
+        self.spoil_in -= 1;
+    }
+
+    pub fn get_pos(&self) -> &Vec2 {
+        &self.pos
+    }
+}
diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..69e3fbe
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,95 @@
+mod snake;
+mod vec2;
+mod event;
+mod food;
+
+use std::sync::Mutex;
+use std::io;
+use std::thread;
+use std::time::Duration;
+use tui::Terminal;
+use tui::backend::TermionBackend;
+use tui::widgets::{Block, Borders};
+use tui::style::Color;
+use tui::widgets::canvas::{Canvas};
+use termion::screen::AlternateScreen;
+use termion::raw::IntoRawMode;
+use termion::event::Key;
+
+use event::Events;
+use snake::Snake;
+use vec2::Vec2;
+use food::Food;
+
+const SCREEN_WIDTH: f64 = 360.0;
+const SCREEN_HEIGHT: f64 = 180.0;
+
+fn main() -> Result<(), io::Error> {
+    let stdout = io::stdout().into_raw_mode()?;
+    let stdout = AlternateScreen::from(stdout);
+    let backend = TermionBackend::new(stdout);
+    let mut terminal = Terminal::new(backend)?;
+
+    let mut snake = Snake::new(0.0, 0.0, Color::LightBlue);
+    let mut food_pool: Vec<Food> = Vec::new();
+
+    while food_pool.len() < 15 {
+        food_pool.push(Food::new());
+    }
+
+    let food_pool = Mutex::new(food_pool);
+
+    let events = Events::new();
+    loop {
+        thread::sleep(Duration::from_millis(15));
+
+        terminal.draw(|f| {
+            let canvas = Canvas::default()
+                .block(Block::default()
+                             .title("Canvas")
+                             .borders(Borders::ALL))
+                             .x_bounds([-SCREEN_WIDTH/2.0, SCREEN_WIDTH/2.0])
+                             .y_bounds([-SCREEN_HEIGHT/2.0, SCREEN_HEIGHT/2.0])
+                .paint(|ctx| {
+                    //ctx.draw(&snake);
+                    snake.draw_big(ctx);
+
+                    for food in &*food_pool.lock().unwrap() {
+                        food.draw(ctx);
+                    }
+                });
+
+            f.render_widget(canvas, f.size());
+        })?;
+
+        snake.advance();
+
+        if snake.collides_with(&snake) {
+            return Ok(());
+        }
+
+        for key in events.last() {
+            match key {
+                Key::Ctrl(c) => if c == 'c' { return Ok(()); },
+                Key::Up => snake.change_direction(Vec2::new(0.0, 1.0)),
+                Key::Left => snake.change_direction(Vec2::new(-1.0, 0.0)),
+                Key::Down => snake.change_direction(Vec2::new(0.0, -1.0)),
+                Key::Right => snake.change_direction(Vec2::new(1.0, 0.0)),
+                _ => {}
+            }
+        }
+        let mut food_pool = food_pool.lock().unwrap();
+        snake.try_eat(&mut food_pool);
+
+        for food in &mut *food_pool {
+            food.tick_spoil();
+        }
+
+        for i in 0..food_pool.len() {
+            if food_pool[i].rotten() {
+                food_pool.swap_remove(i);
+                food_pool.push(Food::new());
+            }
+        }
+    }
+}
diff --git a/src/snake.rs b/src/snake.rs
new file mode 100644
index 0000000..8e06cf8
--- /dev/null
+++ b/src/snake.rs
@@ -0,0 +1,183 @@
+use std::ptr;
+use std::collections::LinkedList;
+use tui::widgets::canvas::{Shape, Painter, Line, Context};
+use tui::style::Color;
+use crate::vec2::Vec2;
+use crate::food::Food;
+
+pub struct Snake {
+    body: LinkedList<Vec2>,
+    color: Color,
+    direction: Vec2,
+    speed: Vec2,
+}
+
+impl Shape for Snake {
+    fn draw(&self, painter: &mut Painter) {
+        let mut body = self.body.iter();
+        let mut last = body.next().unwrap();
+
+        for node in body {
+            let line = Line {
+                x1: last.x,
+                y1: last.y,
+                x2: node.x,
+                y2: node.y,
+                color: self.color,
+            };
+            line.draw(painter);
+            last = node;
+        }
+
+        let head = self.get_head();
+        let head_point = Line {
+            x1: head.x,
+            y1: head.y,
+            x2: head.x,
+            y2: head.y,
+            color: Color::LightYellow
+        };
+
+        head_point.draw(painter);
+    }
+}
+
+impl Snake {
+    fn draw_segment(&self, node1: Vec2, node2: Vec2, ctx: &mut Context) {
+        let x1 = node1.x as i32;
+        let x2 = node2.x as i32;
+        let y1 = node1.y as i32;
+        let y2 = node2.y as i32;
+
+        let x_range = if x2 > x1 {
+            x1..=x2
+        } else {
+            x2..=x1
+        };
+        let y_range = if y2 > y1 {
+            y1..=y2
+        } else {
+            y2..=y1
+        };
+
+        if x2 == x1 {
+            for y in y_range {
+                ctx.print(node1.x as f64, y as f64, "|", self.color);
+            }
+        } else {
+            for x in x_range {
+                ctx.print(x as f64, node2.y as f64, "-", self.color);
+            }
+        }
+    }
+
+    pub fn draw_big(&self, ctx: &mut Context) {
+        let mut body = self.body.iter();
+        let mut last = body.next().unwrap();
+
+        for node in body {
+            self.draw_segment(*last, *node, ctx);
+            last = node;
+        }
+        ctx.layer();
+
+        let head = self.get_head();
+        ctx.print(head.x, head.y, "*", Color::LightYellow);
+    }
+
+    pub fn new(x: f64, y: f64, color: Color) -> Self {
+        Self {
+            body: LinkedList::from([Vec2::new(x, y), Vec2::new(x-5.0, y)]),
+            color,
+            direction: Vec2::new(1.0, 0.0),
+            speed: Vec2::from_single(1.0),
+        }
+    }
+
+    pub fn change_direction(&mut self, direction: Vec2) {
+        if self.direction != direction  && self.direction != -direction {
+            self.direction = direction;
+
+            // Create a new edge at current head position
+            let head = self.body.pop_front().unwrap();
+            self.body.push_front(head);
+            self.body.push_front(head);
+        }
+    }
+
+    pub fn grow(&mut self, multiplier: Vec2) {
+        let mut prev_tail = self.body.pop_back().unwrap();
+        let tail = self.body.pop_back().unwrap();
+
+        if tail == prev_tail {
+            self.body.push_back(tail);
+            self.grow(multiplier);
+            return;
+        }
+
+        prev_tail += tail.direction_to(&prev_tail) * multiplier;
+        self.body.push_back(tail);
+        self.body.push_back(prev_tail);
+    }
+
+    pub fn advance(&mut self) {
+        let mut head = self.body.pop_front().unwrap();
+        head += self.direction * self.speed;
+        self.body.push_front(head);
+
+        self.grow(-self.speed);
+    }
+
+    fn nodes_collide(target: &Vec2, node1: &Vec2, node2: &Vec2) -> bool {
+        if node1.x == node2.x && node1.x == target.x {
+            if node1.y < node2.y {
+                target.y >= node1.y && target.y <= node2.y
+            } else {
+                target.y <= node1.y && target.y >= node2.y
+            }
+        } else if node1.y == node2.y && node1.y == target.y {
+            if node1.x < node2.x {
+                target.x >= node1.x && target.x <= node2.x
+            } else {
+                target.x <= node1.x && target.x >= node2.x
+            }
+        } else {
+            false
+        }
+    }
+
+    pub fn collides_with(&self, other: &Self) -> bool {
+        let my_head = self.get_head();
+
+        let mut nodes = other.body.iter();
+        let mut last = nodes.next().unwrap();
+
+        // If checking against itself, skip first section
+        if ptr::eq(self, other) {
+            last = nodes.next().unwrap();
+        }
+
+        for node in nodes {
+            if Self::nodes_collide(my_head, last, node) {
+                return true;
+            }
+            last = node;
+        }
+
+        false
+    }
+
+    pub fn get_head(&self) -> &Vec2 {
+        self.body.iter().next().unwrap()
+    }
+
+    pub fn try_eat(&mut self, food_pool: &mut Vec<Food>) {
+        for i in 0..food_pool.len() {
+            if (*food_pool[i].get_pos() - *self.get_head()).len() <= self.speed.x + 2.0 {
+                food_pool.swap_remove(i);
+                self.grow(Vec2::from_single(12.0));
+                break;
+            }
+        }
+    }
+}
diff --git a/src/vec2.rs b/src/vec2.rs
new file mode 100644
index 0000000..ff1878f
--- /dev/null
+++ b/src/vec2.rs
@@ -0,0 +1,167 @@
+use std::ops::{Add, AddAssign, Neg, Mul, Div, Sub, SubAssign};
+use std::cmp::PartialEq;
+
+#[derive(Debug, Copy, Clone)]
+pub struct Vec2 {
+    pub x: f64, 
+    pub y: f64
+}
+
+impl Vec2 {
+    pub fn new(x: f64, y: f64) -> Self {
+        Self { x, y }
+    }
+
+    pub fn from_single(a: f64) -> Self {
+        Self { x: a, y: a }
+    }
+
+    pub fn origin() -> Self {
+        Self { x: 0.0, y: 0.0 }
+    }
+
+    pub fn len(&self) -> f64 {
+        (self.x.powf(2.0) + self.y.powf(2.0)).sqrt()
+    }
+
+    pub fn normal(&self) -> Self {
+        let hipothenuse = self.len();
+        if hipothenuse > 0.0 {
+            Self {
+                x: self.x / hipothenuse,
+                y: self.y / hipothenuse,
+            }
+        } else {
+            self.clone()
+        }
+    }
+
+    pub fn direction_to(&self, other: &Self) -> Self {
+        (*other - *self).normal()
+    }
+}
+
+impl Add for Vec2 {
+    type Output = Self;
+
+    fn add(self, rhs: Self) -> Self {
+        Self { x: self.x + rhs.x, y: self.y + rhs.y }
+    }
+}
+
+impl Sub for Vec2 {
+    type Output = Self;
+
+    fn sub(self, rhs: Self) -> Self {
+        Self {x: self.x - rhs.x, y: self.y - rhs.y}
+    }
+}
+
+impl AddAssign for Vec2 {
+    fn add_assign(&mut self, rhs: Self) {
+        self.x += rhs.x;
+        self.y += rhs.y;
+    }
+}
+
+impl SubAssign for Vec2 {
+    fn sub_assign(&mut self, rhs: Self) {
+        self.x -= rhs.x;
+        self.y -= rhs.y;
+    }
+}
+
+impl PartialEq for Vec2 {
+    fn eq(&self, other: &Self) -> bool {
+        self.x == other.x && self.y == other.y
+    }
+}
+
+impl Mul for Vec2 {
+    type Output = Self;
+
+    fn mul(self, rhs: Self) -> Self {
+        Self { x: self.x * rhs.x, y: self.y * rhs.y }
+    }
+}
+
+impl Div for Vec2 {
+    type Output = Self;
+
+    fn div(self, rhs: Self) -> Self {
+        Self {
+            x: if rhs.x > 0.0 { self.x / rhs.x } else { 0.0 },
+            y: if rhs.y > 0.0 { self.y / rhs.y } else { 0.0 },
+        }
+    }
+}
+
+impl Neg for Vec2 {
+    type Output = Self;
+
+    fn neg(self) -> Self {
+        Self {
+            x: -self.x,
+            y: -self.y,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Vec2;
+
+    #[test]
+    fn direction_0deg() {
+        let v1 = Vec2::origin();
+        let v2 = Vec2::new(2.0, 0.0);
+        let result = Vec2::new(1.0, 0.0);
+
+        assert_eq!(result, v1.direction_to(&v2));
+    }
+
+    #[test]
+    fn direction_45deg() {
+        let v1 = Vec2::origin();
+        let v2 = Vec2::from_single(1.0);
+        let result = Vec2::from_single(1.0/(2.0_f64).sqrt());
+
+        assert_eq!(result, v1.direction_to(&v2));
+    }
+
+    #[test]
+    fn direction_90deg() {
+        let v1 = Vec2::origin();
+        let v2 = Vec2::new(0.0, 23.121);
+        let result = Vec2::new(0.0, 1.0);
+
+        assert_eq!(result, v1.direction_to(&v2));
+    }
+
+    #[test]
+    fn direction_180deg() {
+        let v1 = Vec2::origin();
+        let v2 = Vec2::new(-82.1, 0.0);
+        let result = Vec2::new(-1.0, 0.0);
+
+        assert_eq!(result, v1.direction_to(&v2));
+    }
+
+    #[test]
+    fn direction_270deg() {
+        let v1 = Vec2::origin();
+        let v2 = Vec2::new(0.0, -2.8);
+        let result = Vec2::new(0.0, -1.0);
+
+        assert_eq!(result, v1.direction_to(&v2));
+    }
+
+    #[test]
+    fn direction_not_origin() {
+        let v1 = Vec2::from_single(1.0);
+        let v2 = Vec2::from_single(3.0);
+        let result = Vec2::from_single(1.0/(2.0_f64).sqrt());
+
+        assert_eq!(result, v1.direction_to(&v2));
+    }
+}