"use strict";

import Vector from './Vector';

class Star
{
	constructor(inCanvas, inPosition, inSize)
	{
		this.canvas = inCanvas;
		
		this.position = inPosition;
		this.rotation = 0;
		this.rotationStep = 0;
		this.alpha = 1;
		
		this.pointCount = 5;
		
		this.size = inSize;
		this.innerRingRatio = 0.5;
		
		this.colour = "white";
	}
	
	/**
	 * The step around a circle (in radians) between each point (both inner and
	 * outer) on the star.
	 * Used by recalculatePoints().
	 * @return {number} The step around a circle between each point on the star.
	 */
	get pointStep()
	{
		return (Math.PI * 2) / (this.pointCount * 2);
	}
	
	get innerRingSize()
	{
		return this.innerRingRatio * this.size;
	}
	
	recalculatePoints()
	{
		this.points = [];
		for (let n = 0, i = 0; n < Math.PI * 2; n += this.pointStep, i++)
		{
			let currentSize = i % 2 == 0 ? this.size : this.innerRingSize;
			this.points.push(new Vector(
				currentSize * Math.cos(Math.PI * 2 * (n / (Math.PI * 2)) - Math.PI / 2),
				currentSize * Math.sin(Math.PI * 2 * (n / (Math.PI * 2)) - Math.PI / 2)
			));
		}
	}
	
	update(dt)
	{
		this.rotation += this.rotationStep * dt;
		// if(this.rotation > Math.PI * 2)
		// 	this.rotation -= Math.PI * 2;
		// if(this.rotation < 0)
		// 	this.rotation += Math.PI * 2;
	}
	
	render(context)
	{
		if(!(this.points instanceof Array))
			this.recalculatePoints();
		
		context.save();
		context.translate(this.position.x, this.position.y);
		context.rotate(this.rotation);
		
		context.beginPath();
		context.moveTo(this.points[0].x, this.points[0].y);
		for (let point of this.points) {
			context.lineTo(point.x, point.y);
		}
		context.closePath();
		
		context.globalAlpha = this.alpha;
		context.fillStyle = this.colour;
		context.fill();
		
		context.restore();
	}
}

export default Star;