function doTrafficLights() {
  var activeLight = getActiveLight();
  // your code will replace this call
  // to `console.log()`
  if (activeLight === "red") {
    turnRed() ;
  } else if (activeLight === "yellow") {
    turnYellow() ;
  } else {
    turnGreen() ;
  }

}


/* From here down, you are not expected to
   understand.... for now :)


   Nothing to see here!

*/


function turnOffLights() {
  $('.traffic-light').removeClass('yellow-on red-on green-on');
}

function turnGreen() {
  turnOffLights();
  $('.green-light').addClass('green-on');
}

function turnYellow() {
  turnOffLights();
  $('.yellow-light').addClass('yellow-on');
}

function turnRed() {
  turnOffLights();
  $('.red-light').addClass('red-on');
}

function getActiveLight() {
  return (['red', 'green', 'yellow'])[Math.floor(Math.random() * 3)];
}

function handleClicks() {
  $('.js-control-lights').click(function() {
    doTrafficLights();
  });
}

$(handleClicks);

/*-----------------------------------*/

function main() {
  try {
    doAllTheThings();
  }
  catch(e) {
    console.error(e);
    reportError(e);
  }
}

function doAllTheThings() {
  throw {
    message: "Everything's ruined",
    name: "FatalException",
    toString: function(){return this.name + ": " + this.message;}
  }
}

function reportError(e) {
  $('.js-error-report').text("Uh oh, something went wrong! Here's what we know: " + e.message);
}



/* From here down, you are not expected to
   understand.... for now :)


   Nothing to see here!

*/