snake

snake.js

function P(x, y) {
    return {
        x: x,
        y: y
    }
}
function R() {
    return {
        x: Math.floor(Math.random() * 16),
        y: Math.floor(Math.random() * 16)
    }
}
function A(a, b) {
    return {
        x: a.x + b.x,
        y: a.y + b.y
    }
}
function Q(a, b) {
    return a.x == b.x && a.y == b.y
}
function O(p) {
    return p.x < 0 || p.x > 15 || p.y < 0 || p.y > 15
}
function T(p) {
    return s.filter(Q.bind(this, p)).length
}
function M(p) {
    if (p.x != -d.x && p.y != -d.y) m = p
}
function B(l) {
    s.map(function (p) {
        c.fillRect(p.x << 3, p.y << 3, 8, 8)
    })
}
function C(p) {
    c.beginPath();
    c.arc((p.x << 3) + 4, (p.y << 3) + 4, 4, 0, 7);
    c.fill()
}
function F() {
    clearInterval(t);
    setTimeout(I, 5000);
    alert('FAIL')
}
window.addEventListener('keydown', function (e) {
    M({
        37: P(-1, 0),
        38: P(0, -1),
        39: P(1, 0),
        40: P(0, 1)
    }[e.keyCode])
}, false);

function I() {
    document.body.innerHTML = '<canvas width=128 height=128 style="width:256px;height:256px;border:8px solid black"></canvas>';
    c = document.body.firstChild.getContext('2d');
    s = [P(8, 8), P(7, 8), P(6, 8)];
    a = R();
    m = P(1, 0);
    t = setInterval(function () {
        d = m;
        n = A(s[0], d);
        (O(n) || T(n)) && F();
        s.unshift(n);
        Q(s[0], a) && (a = R()) || s.pop();
        c.clearRect(0, 0, 128, 128);
        B(s);
        C(a)
    }, 500);
}
setTimeout(I, 0)