(load "bunnu.k")
[Shell grammar: 'bunnu]

println "Hello world\n";

// Show a canvas

var canvas = ImageBox.newImage:(SDLImage.newExtent:([400, 400].asPoint()));
var frame = FrameBox.with:title:(canvas, "turtle");
frame.position:([440, 10].asPoint());
Window.default().addFront:(frame);

// Prepare the context and draw a circle just for testing.

var ctx = SDLContext.new:(canvas.image());
ctx.color:(Color.withR:withG:withB:(200, 180, 60));
ctx.fillCircle:radius:([100,50].asPoint(), 80);
canvas.damaged();


// Setting up the turtle.
var x = 200;
var y = 200;
var angle = 0;

// Define a couple of turtle functions.
var forward = function(n) {
  var newX = x + n * angle.cos();
  var newY = y + n * angle.sin();
  ctx.color:(Color.withR:withG:withB:(0, 150, 20));
  ctx.drawLine:to:(Point.withX:withY:(x, y).asPoint(), Point.withX:withY:(newX,newY).asPoint());
  canvas.damaged();
  x = newX;
  y = newY;
};

var turn = function(n) {
  angle = angle + n * Float.pi() / 180;
};

var clean = function() {
  ctx.color:(Color.withR:withG:withB:(255, 255, 255));
  ctx.fillRectangle:extent:([0,0].asPoint(), [400,400].asPoint());
  x = 200;
  y = 200;
  angle = 0;
  canvas.damaged();
};

forward(100);
turn(144);

clean();
for (i = 1; i <= 40; i = i + 1) {
  forward(4 * i);
  turn(89);
}


var inspi = function(side, angle, inc) {
  for (i = 0; i < 2000; i = i + 1) {
    forward(side);
    turn(angle + inc * i);
  }
};

inspi(20, 40, 30);

canvas.onMotion: = function (event) {
  clean();
  inspi(8, event.position().x(), event.position().y());
};