;(()=>{
  
	"use strict";
	const POINT_NUM = 20;
  const FILLL_COLORS = ["#8AB3BB","#82A5AD","#8AB4BD","#92C1CB","#7CADB6","#97CBD5","#82A5AC","#8AB4BD"]
	/**
	 * キャンバスオブジェクト
	 * @param {string} canvasId canvasのid属性
	 */
	class Canvas{
		constructor(canvasId) {
			var canvas  = document.getElementById(canvasId);
			this.ctx    = canvas.getContext('2d');
			this.canvasW = canvas.width;
			this.canvasH = canvas.height;
		}
		clear(){
			this.ctx.clearRect(0, 0, this.canvasW , this.canvasH );
		}
	}
	/**
	 * 座標オブジェクト
	 * @param {number} x X座標
	 * @param {number} y Y座標
	 */
	class Point{
		constructor(x,y) {
			this.x = x;
			this.y = y;
		}
		isEqual(point) {
			return (this.x === point.x && this.y === point.y);
		}
	}
	/**
	 * 辺オブジェクト
	 * @param {Point} start 開始座標
	 * @param {Point} end 終了座標
	 */
	class Edge{
		constructor(start,end) {
			this.start = start;
			this.end   = end;
		}
		isEqual(edge) {
			return (
				(this.start.isEqual(edge.start) && this.end.isEqual(edge.end)) ||
				(this.start.isEqual(edge.end)   && this.end.isEqual(edge.start))
			);
		}
	}
	/**
	 * 多角形オブジェクト
	 * @param {Array} points 座標情報
	 */
	class Polygon{
		constructor(points) {
			this.points = points;
		}
		draw(ctx,strokeStyle,fillStyle){
			ctx.beginPath();
			ctx.moveTo(this.points[0].x, this.points[0].y);
			for(var i=1; i<this.points.length ; i++){
				ctx.lineTo(this.points[i].x, this.points[i].y);
			}
			ctx.closePath();
			if(strokeStyle){
				ctx.strokeStyle = strokeStyle;
				ctx.stroke();
			}
			if(fillStyle){
				ctx.fillStyle   = fillStyle;
				ctx.fill();
			}
		}
	}
	/**
	 * 三角形オブジェクト
	 * @param {Array} points 座標情報
	 */
	class Triangle extends Polygon{
		/**
		* 外接円の取得
		*/
		getCircumscribedCircle() {
			//未定義の場合は定義
			if(!this._circumscribedCircle){
				var x1 = this.points[0].x;
				var y1 = this.points[0].y;
				var x2 = this.points[1].x;
				var y2 = this.points[1].y;
				var x3 = this.points[2].x;
				var y3 = this.points[2].y;
				
				//各座標の2乗を取得
				var x1pow2 = Math.pow(x1,2);
				var x2pow2 = Math.pow(x2,2);
				var x3pow2 = Math.pow(x3,2);
				var y1pow2 = Math.pow(y1,2);
				var y2pow2 = Math.pow(y2,2);
				var y3pow2 = Math.pow(y3,2);
				
				//公式より中心座標を取得
				var c = 2 * ((x2 - x1) * (y3 - y1) - (y2 - y1) * (x3 - x1));
				var x = ((y3 - y1) * (x2pow2 - x1pow2 + y2pow2 - y1pow2) + (y1 - y2) * (x3pow2 - x1pow2 + y3pow2 - y1pow2)) / c;
				var y = ((x1 - x3) * (x2pow2 - x1pow2 + y2pow2 - y1pow2) + (x2 - x1) * (x3pow2 - x1pow2 + y3pow2 - y1pow2)) / c;
				
				//外接円の半径rは、中心から三角形の任意の頂点(x1,y1)までの距離
				var r = Math.sqrt(Math.pow(x1 - x,2) + Math.pow(y1 - y,2));
				this._circumscribedCircle =  new Circle(new Point(x,y),r);
			}
			return this._circumscribedCircle;
		}
		/**
		* 辺の取得
		*/
		getEdges(){
			//未定義の場合は定義
			if(!this._edges){
				this._edges = [];
				this._edges.push(new Edge(this.points[0],this.points[1]));
				this._edges.push(new Edge(this.points[1],this.points[2]));
				this._edges.push(new Edge(this.points[2],this.points[0]));
			}
			return this._edges;
		}
	}
/**
 * 円オブジェクト
 * @param {Point} center 中心座標情報
 * @param {number} radius 半径
 */
class Circle{
	constructor(center,radius){
		this.center = center;
		this.radius = radius;
	}
	/**
	 * 円内に引数の点が含まれているか確認
	 */
	isInclude(point) {
		var x = point.x - this.center.x;
		var y = point.y - this.center.y;
		var len = Math.sqrt((x * x) + (y * y));
		return len < this.radius;
	}
	/**
	* 描画
	*/
	draw(ctx,strokeStyle,fillStyle){
		ctx.beginPath();
		ctx.arc(this.center.x,this.center.y,this.radius,0,Math.PI*2,true);
		if(strokeStyle){
			ctx.strokeStyle = strokeStyle;
			ctx.stroke();
		}
		if(fillStyle){
			ctx.fillStyle   = fillStyle;
			ctx.fill();
		}
	}
};
	//表示処理
	var canvas = new Canvas("ctx");
	canvas.clear();

  var stage = {
    x : 0,
    y : 0,
    w : 400,
    h : 400
  }

	//ステージを描画
	//stage.obj = new Polygon([
	//	new Point(stage.x         , stage.y        ) , 
	//	new Point(stage.x+stage.w , stage.y        ) , 
	//	new Point(stage.x+stage.w , stage.y+stage.h) , 
	//	new Point(stage.x         , stage.y+stage.h) 
	//]);
	//stage.obj.draw(canvas.ctx,"gray");

	//ステージ内にランダムなポイントを取得
	var trianglePoints = [];
	for (var i = 0; i < POINT_NUM ; i++) {
		trianglePoints.push(new Point(
			stage.x+Math.random() * stage.w , 
			stage.y+Math.random() * stage.h
		));
	}
	trianglePoints.push(new Point(stage.x         , stage.y        )); 
	trianglePoints.push(new Point(stage.x+stage.w , stage.y        )); 
	trianglePoints.push(new Point(stage.x+stage.w , stage.y+stage.h)); 
	trianglePoints.push(new Point(stage.x         , stage.y+stage.h));
  //ランダムなポイントを描画
	//trianglePoints.forEach((point)=>{
	//	(new Circle(point,2)).draw(canvas.ctx,"red");
	//});

	//ステージを包む外接円
	var stageCircumscribedCircleRadius = Math.sqrt((stage.w*stage.w) + (stage.h*stage.h))/2;
	var stageCircumscribedCircleCenter = new Point(stage.x+stage.w/2,stage.y+stage.h/2);
	// (new Circle(stageCircumscribedCircleCenter,stageCircumscribedCircleRadius)).draw(canvas.ctx,"green");

	var circumscribedTrianglePoints = [],
		circumscribedTriangles = [];
	//ステージを包む外接円を包む外接三角形の頂点を取得
	circumscribedTrianglePoints.push(new Point(
		stageCircumscribedCircleCenter.x- Math.sqrt(3) * stageCircumscribedCircleRadius,
		stageCircumscribedCircleCenter.y-stageCircumscribedCircleRadius
	));
	circumscribedTrianglePoints.push(new Point(
		stageCircumscribedCircleCenter.x+Math.sqrt(3) * stageCircumscribedCircleRadius,
		stageCircumscribedCircleCenter.y-stageCircumscribedCircleRadius
	));
	circumscribedTrianglePoints.push(new Point(
		stageCircumscribedCircleCenter.x,
		stageCircumscribedCircleCenter.y+stageCircumscribedCircleRadius*2
	));
	//ステージを包む外接円を包む外接三角形を作成
	circumscribedTriangles.push(new Triangle(circumscribedTrianglePoints));
	//ステージを包む外接円を包む外接三角形を描画
	// circumscribedTriangles[0].draw(canvas.ctx,"yellow");

/**
* ドロネー分割
* @return {Array} ドロネー分割された三角形リスト
*/
var delaunayDiagram = (points,baseTriangle) => {
	//外部三角形を格納
	var triangles = baseTriangle
	//ドロネー分割
	points.forEach(function(point){
		var edges = [];
		var unique_edges = [];
		//ポイントを外接円に含む三角形を抽出、辺に分解
		triangles.forEach(function(targetTriangle,i){
			if(targetTriangle.getCircumscribedCircle().isInclude(point)){
				edges = edges.concat(targetTriangle.getEdges());
				delete triangles[i];
			}
		});
		//分解した辺リストから重複する辺を削除
		edges.forEach(function(edge0,i){
			var unique_flag =true;
			edges.forEach(function(edge1,j){
				//重複する辺がある場合
				if (i != j && edge0.isEqual(edge1)) {
					unique_flag= false;
				}
			});
			if(unique_flag){
				unique_edges.push(edge0)
			}
		});
		edges = unique_edges;
		//重複しない辺リストから三角形を生成
		edges.forEach(function(edge,i){
			triangles.push(new Triangle([edge.start, edge.end, point]));
		});
	});
	return triangles;
}
var triangles = delaunayDiagram(trianglePoints,circumscribedTriangles);
triangles.forEach((triangle,i)=>{
	triangle.draw(canvas.ctx,"gray",FILLL_COLORS[Math.ceil(i%FILLL_COLORS.length)]);
});
})();