feat: snake game

feat: unit.random
feat: ui.center

src/snake.js

@@ -0,0 +1,169 @@
+import Unit from './classes/unit';
+import Interface from './classes/interface';
+import fs from 'fs';
+
+let log = fs.createWriteStream(__dirname + '/log');
+
+let FRAME = 100;
+
+let ui = new Interface();
+
+let snake = [];
+const UP = 0;
+const DOWN = 1;
+const LEFT = 2;
+const RIGHT = 3;
+let head = createPart();
+head.color = '#71da29';
+head.dieOnExit = true;
+createPart();
+createPart();
+
+let point = new Unit(ui);
+point.shape = '+';
+point.color = '#f3ff6a';
+point.random();
+
+let score = 0;
+
+let stop = false;
+function loop() {
+  if (stop) return;
+  ui.clear();
+
+  point.draw();
+
+  snake.forEach((part, i) => {
+    part.draw();
+
+    if (i > 0) part.findWay(i);
+
+    part.move();
+  });
+
+  if (head.collides(point)) {
+    point.random();
+    createPart();
+    score++;
+
+    FRAME--;
+  }
+
+  if (head.collides(snake.slice(2))) {
+    gameover();
+  }
+
+  ui.cursor.goto(0, 0).yellow().write(`Score: ${score}`);
+  ui.cursor.reset();
+
+  setTimeout(loop, FRAME);
+}
+
+loop();
+
+ui.onKey('right', () => {
+  changeDirection(RIGHT);
+});
+ui.onKey('down', () => {
+  changeDirection(DOWN);
+});
+ui.onKey('up', () => {
+  changeDirection(UP);
+});
+ui.onKey('left', () => {
+  changeDirection(LEFT);
+});
+
+ui.onKey(() => {
+  if (!stop) return;
+
+  stop = false;
+  snake = [];
+  head = createPart();
+  head.color = '#71da29';
+  createPart();
+  createPart();
+
+  score = 0;
+
+  point.random();
+
+  loop();
+})
+
+function changeDirection(dir) {
+  head.direction = dir;
+}
+
+function createPart() {
+  let part = new Unit(ui);
+  let last = snake[snake.length - 1];
+
+  let direction;
+  if (!last) {
+    direction = UP;
+  } else {
+    direction = last.direction;
+  }
+
+  part.shape = '•';
+  part.color = '#bdfe91';
+  part.direction = direction;
+  part.changeTo = null;
+
+  part.findWay = function(i) {
+    let ahead = snake[i - 1];
+
+    if (this.changeTo !== null) {
+      this.direction = this.changeTo;
+      this.changeTo = null;
+    }
+    if (this.direction !== ahead.direction) {
+      this.changeTo = ahead.direction;
+    }
+  }
+
+  part.speed = function(multiplier = 1) {
+    let { direction } = part;
+    let x = direction == LEFT ? -1 :
+            direction == RIGHT ? 1 : 0;
+    let y = direction == UP ? -1 :
+            direction == DOWN ? 1 : 0;
+
+    return [x * multiplier, y * multiplier];
+  }
+
+  let [dX, dY] = part.speed();
+  dX *= -1;
+  dY *= -1;
+
+  let x = last ? last.x + dX : ui.center.x;
+  let y = last ? last.y + dY : ui.center.y;
+
+  part.go(x, y);
+
+  snake.push(part);
+  return part;
+}
+
+function gameover() {
+  const MSG = 'Game Over!';
+  ui.cursor.goto(ui.center.x - MSG.length / 2, ui.center.y);
+  ui.cursor.red();
+  ui.cursor.bold();
+  ui.write(MSG);
+
+  ui.cursor.reset();
+  ui.cursor.hex('#f65590');
+  const RETRY = 'Press any key to play again';
+  ui.cursor.goto(ui.center.x - RETRY.length / 2, ui.center.y + 2);
+  ui.write(RETRY);
+
+  stop = true;
+}
+
+process.on('exit', function() {
+  ui.cursor.horizontalAbsolute(0).eraseLine()
+  ui.cursor.show();
+  log.end();
+});