var Controller = function(){
	this.grid_size = {x: 20, y: 20};
	this.initial_length = 3;
	this.time_step = 400;
	this.collectibles = [];
	this.views = [];
	this.snake = new Snake(this.initial_length);
	this.canTurn = true;
	var pos0 = {x: -1, y: -1};
	
	var higgs = new Particle(pos0);
	higgs.mass = 125;
	higgs.type = "Higgs"
	var electron = new Particle(pos0);
	electron.mass = .0005;
	electron.type = "electron";

	this.possible_collectibles = [
		{collectible: higgs, probability: 3e-3},
		{collectible: electron, probability: .5}
		]
	this.stage = new createjs.Stage("demoCanvas");
}

Controller.prototype.update_views = function(){
    for(var view in this.views){
        this.views[view].update();
    }
}

Controller.prototype.spawn_collectibles = function(){
	var collectible = get_random_element_with_probabilities(this.possible_collectibles);
	if (!collectible) return;
	collectible = Object.create(collectible.collectible);
	var rnd_pos = this.get_random_position();
	if (! this.is_position_occupied(rnd_pos)) {
		collectible.position = rnd_pos;
		this.collectibles.push(collectible);
		this.add_view(new ParticleView(collectible));
	}
}

Controller.prototype.start_game = function(){
	// this.session = new Session();
    var c = this;
	createjs.Ticker.on("tick", function(e){c.tick(e);});
	createjs.Ticker.timingMode = createjs.Ticker.RAF;
	this.bind_events();
	this.time = 0;
	this.score = 0;

    for(phModel in controller.snake.physicists){
        var model = controller.snake.physicists[phModel];
        var phView = new PhysicistView(model);
        this.add_view(phView);
    }
}

Controller.prototype.add_view = function(view){
    this.stage.addChild(view);
	this.views.push(view);
}

Controller.prototype.bind_events = function(){
    var c = this;
	window.onkeydown = function(e){
		var direction = null;
		var dir = {x: c.snake.physicists[0].direction.x, y: c.snake.physicists[0].direction.y};

		switch (e.keyCode){
			case 37:
			case 65:
				if(dir.x == 1)
					{
						break;}
				else {
						direction = {x: -1, y: 0};
						break;
					}
			case 38:
			case 87:
				if(dir.y == 1)
					{
						break;}
				else {
						direction = {x: 0, y: -1};
						break;
					}
			case 39:
			case 68:
				if(dir.x == -1)
					{
						break;}
				else {
						direction = {x: 1, y: 0};
						break;
				}
			case 40:
			case 83:
				if(dir.y == -1)
					{
						break;}
				else {
						direction = {x: 0, y: 1};
						break;
					}
		}
		if (direction && c.canTurn){
			c.turn_snake(direction);
			c.canTurn = false;
		}
	}
}

Controller.prototype.turn_snake = function(direction){
	this.snake.physicists[0].direction = direction;
}


Controller.prototype.tick = function(event){
	if(event.time - this.time > this.time_step){
		this.time = event.time;
        var next_cell = this.get_next_cell_position();
		var next_cell_content = this.is_position_occupied(next_cell);
		this.snake.move(next_cell);
		this.canTurn = true;
		if (next_cell_content && next_cell_content.collectible) this.snake.physicists[0].collect(next_cell_content.collectible);
        if(this.collectibles.length < 2){
		    this.spawn_collectibles();
        }
        this.update_views();
	}
	this.stage.update(event);
}

Controller.prototype.get_next_cell_position = function(){
	var ph0 = this.snake.physicists[0];
	var next_cell = Object.create(ph0.position);
	next_cell.x += ph0.direction.x;
	next_cell.y += ph0.direction.y;
	if (next_cell.x < 0) next_cell.x = this.grid_size.x - 1;
	if (next_cell.y < 0) next_cell.y = this.grid_size.y - 1;
	if (next_cell.x == this.grid_size.x) next_cell.x = 0;
	if (next_cell.y == this.grid_size.y) next_cell.y = 0;
	return next_cell;
}

Controller.prototype.get_random_position = function(){
	return {x: Math.floor(Math.random()*this.grid_size.x),
			y: Math.floor(Math.random()*this.grid_size.y)
		};
}

Controller.prototype.is_position_occupied = function(position){
	var phs = this.snake.physicists;
	for (var ph in phs){
		var pos = phs[ph].position;
		if (pos.x == position.x && pos.y == position.y) return {physicist:phs[ph]};
	}
	for (var c in this.collectibles){
		var pos = this.collectibles[c].position;
		if (pos.x == position.x && pos.y == position.y) return {collectible:this.collectibles[c]};
	}
	return null;
}

Controller.prototype.hit_test = function(e, particle){
	for (var ph_i in this.snake.physicists){
		var ph = this.snake.physicists[ph_i];
		if (ph.view.hitTest(e.x, e.y)) {
			this.ph.collect(particle);
		}
	}
}

Controller.prototype.remove_collectible = function(collectible){
	var i = this.collectibles.indexOf(collectible);
	if (i > -1) {
	    this.collectibles.splice(i, 1);
	}
	i = -1;
	i = this.views.indexOf(collectible.view);
	if (i > -1) {
	    this.views.splice(i, 1);
	}
	this.stage.removeChild(collectible.view);
}

var get_random_element_with_probabilities = function(array){
	var previous_probability = 0;
	var rnd = Math.random();
	for (ind in array){
		var probability = array[ind].probability;
		if (rnd  < probability + previous_probability) return array[ind];
		previous_probability += probability;
	}
	return null;
}