Accidental Solution to Bit's Quest #10 and #12

/*
 * Boilerplate Code. Here we assign a numerical index to each direction for
 * sensors and thrusters. We also have all sensor events call the "sense"
 * method so we can handle them all generically.
 */

var $this = this;
var directions = ["right", "bottom", "left", "top"];
var sensors   = [];
var thrusters = [];

for (var _i = 0; _i < 4; ++_i)
  (function() {
    var i = _i;
    this.on('sensor:' + directions[_i], function(c)
    {
      sensors[i] = c;
      sense.call(this, i);
    });

    sensors[i] = false;
 	thrusters[i] = this.thrusters[directions[i]];
  }).call(this);


/*
 * First we move to a wall: Our algorithm only knows how to follow walls to
 * the solution, and it expects to start against a wall, with no thrusters
 * running.
 */

this.on('start', function() {
  this.thrusters.top(true);

  var initialized = false;
  this.on('sensor:bottom', function() {
    if (!initialized)
    {
      initialized = true;
      this.thrusters.top(false);
    }
  });
});


/*
 * We either found a new wall, or a wall is no longer next to us. For each
 * wall we're next to, turn on the thruster clockwise to that wall. If we are
 * no longer next to a wall, go towards the last disappeared wall.
 */

function sense(i) {
  var anySensors = false;
  for (j in sensors)
    anySensors = anySensors || sensors[j];

  // A new direction to unexplored area just opened up, go to it
  if (! anySensors)
    thrusters[(i+2)%4](true);

  // Turn on a thruster clockwise from the wall we just encountered
  // Or, turn it off if there is no wall anymore.
  thrusters[(i+3)%4](sensors[i]);
};