$(document).ready(function(){
	var canvas = $("#game_canvas");
	var context = canvas.get(0).getContext("2d");

	// Canvas dimensions
	var canvas_width = canvas.width();
	var canvas_height = canvas.height();

	// Game settings.
	var play_game;
	var platform_x;
	var platform_y;
	var platform_outer_radius;
	var platform_inner_radius;
	var asteroids;
	var player;
	var player_original_x;
	var player_original_y;
	var ui = $("#game_ui");
	var ui_intro = $("#game_intro");
	var ui_stats = $("#game_stats");
	var ui_complete = $("#game_complete");
	var ui_play = $("#game_play");
	var ui_reset = $(".game_reset");
	var ui_remaining = $("#game_remaining");
	var ui_score = $(".game_score");

	var Asteroid = function(x, y, radius, mass, friction){
		this.x = x;
		this.y = y;
		this.radius = radius;
		this.mass = mass;
		this.friction = friction;
		this.v_x = 0;
		this.v_y = 0;

		this.player = false;
	};

	// Reset and start the game
	function start_game(){
		ui_score.html("0");
		ui_stats.show();

		// Set up initial game settings
		play_game = false;
		platform_x = canvas_width / 2;
		platform_y = 150;
		platform_outer_radius = 100;
		platform_inner_radius = 75;
		asteroids = new Array();

		var outer_ring = 8; // Asteroids around outer ring
		var ring_count = 3; // Number of rings
		var ring_spacing = (platform_inner_radius / (ring_count - 1)); 	// Distance between
																		// each ring.
		for(var r = 0; r < ring_count; r++){
			var current_ring = 0; // Asteroids around current ring
			var angle = 0; // Angle between each asteroid
			var ring_radius = 0;

			// Is this the innermost ring?
			if(r == ring_count -1){
				current_ring = 1;
			} else {
				current_ring = outer_ring - (r * 3);
				angle = 360 /  current_ring;
				ring_radius = platform_inner_radius - (ring_spacing * r);
			};

			for(var a = 0; a < current_ring; a++){
				var x = 0;
				var y = 0;

				// Is this the innermost ring?
				if(r == ring_count - 1){
					x = platform_x;
					y = platform_y;
				} else {
					x = platform_x + (ring_radius * Math.cos((angle * a)
						* (Math.PI / 180)));
					y = platform_y + (ring_radius * Math.sin((angle * a)
						* (Math.PI / 180)));
				};

				var radius = 10;
				var mass = 5;
				var friction = 0.95;
				asteroids.push(new Asteroid(x, y, radius, mass, friction));
			};
		};

		// Start the animation loop
		animate();
	};

	// Initialize game environment
	function init(){
		ui_stats.hide();
		ui_complete.hide();

		ui_play.click(function(e){
			e.preventDefault();
			ui_intro.hide();
			start_game();
		});

		ui_reset.click(function(e){
			e.preventDefault();
			ui_complete.hide();
			start_game();
		});
	};

	// Animation loop that does all the fun stuff
	function animate(){
		// Clear
		context.clearRect(0, 0, canvas_width, canvas_height);

		context.fillStyle = "rgb(100, 100, 100)";
		context.beginPath();
		context.arc(platform_x, platform_y, platform_outer_radius, 0,
			Math.PI * 2, true);
		context.closePath();
		context.fill();

		if(play_game){
			// Run the animation loop again in 33 ms
			setTimeout(animate, 33);
		};
	};

	init();
});