import flash.events.KeyboardEvent;
import Particle;

// Define our vector (just a dynamic array with a specied type in AS3!)
var particleVect:Vector.<Particle> = new Vector.<Particle>;

// Define our number of particles to display on the screen and a start/stop animation flag
var numberOfParticles:uint = 200;

function addParticles():void
{
	// Create however many particles we've entered into our numberOfParticles variable
	for (var loop:uint = 0; loop < numberOfParticles; loop++) {
	
		// Create a new instance of Particle and add it to our Vector of Particles
		particleVect.push(new Particle());
		
		// Randomise the x (horizontal) and y (vertical) locations on stage 
		particleVect[loop].x = Math.random() * stage.stageWidth;
		particleVect[loop].y = Math.random() * stage.stageHeight;

		// Randomise alpha
		particleVect[loop].alpha = Math.random();
	
		// Randomise size between 0% and 100% (i.e. between 0.0 and 1.0)
		var sizeScale:Number = Math.random(); 
		particleVect[loop].scaleX = sizeScale;
		particleVect[loop].scaleY = sizeScale;	
		
		// Add the particle to the stage
		addChild(particleVect[loop]);
		
	} // End of for loop
	
} // End of addParticles function

function removeParticles():void
{
	// Remove however many particles we're working with from the stage
	for (var loop:uint = 0; loop < numberOfParticles; loop++) {
		
		// Call our custom destructor to unbind any particle eventListeners
		particleVect[loop].ParticleDestructor();
		
		// Remove the particle from the stage
		removeChild(particleVect[loop]);		
		
	}
	// Remove all but a single particle from the vector.
	// We cannot remove the last particle or it will completely destroy our global Particle vector
	// and if that happens, we cannot re-instantiate the global Particle vector from here when
	// (and if!) we want to resume animation! This is the same reason we can't just use "particleVect = null;"!!
	while(particleVect.length > 0) {
		particleVect.pop();
	}
	
} // End of removeParticles function

function particleController(e:KeyboardEvent):void
{
	// If the animation is stopped, add the particles and flip the flag
	if (toggleAnimation == false) 
	{
		addParticles();
		toggleAnimation = true;
	}
	else {
		// Otherwise animation must be running and we want it to stop, so remove the
		// particles and flip the flag
		removeParticles();
		toggleAnimation = false;
	}
	
} // End of particleController function

// With all our functions in place, bind the particle controller function to a keypress
stage.addEventListener(KeyboardEvent.KEY_DOWN, particleController);

// Kick off the animation without waiting for keypress, but still allow a keypress to toggle the animation
addParticles();
var toggleAnimation = true;