/**
* 導航網格類 左上角為原點(0,0)
 * @author BrightLi
 * @since 2020/4/18
 */

import Node from "./Node";
import AStar from "./AStar"

export default class Grid 
{
private _startNode:Node; //起點
private _endNode:Node; //終點
private _nodes:Array<Array<Node>>; //Node數組
private _width:number; //網格列數
private _height:number; //網格行數
	private _astar:AStar;

// 構造函數
	public constructor(width:number, height:number) {
		this._width = width;
		this._height = height;
		this._nodes = [];
		var x:number,y:number;
		for(x=0;x<width;x++){
			this._nodes[x] = [];
			for(y=0;y<height;y++){
				this._nodes[x][y] = new Node(x,y);
			}
		}
		this._astar=new AStar();
	}
// 獲得節點
	public getNodeAt(x:number , y:number):Node{
		var result=this._nodes[x][y];
		// result.reset();
		return result;
	}
// 是否可以行走
	public isWallableAt(x:number,y:number):boolean{
		return this.isInside(x,y) && this._nodes[x][y].walkable;
	}
// 設置坐標是否可以行走
	public setWalkableAt(x:number, y:number, value:boolean){
		this._nodes[x][y].walkable = value;
	}
// 設置起點
	public setStartNode(x:number,y:number){
		this._startNode=new Node(x,y);
	}
// 設置終點
	public setEndNode(x:number,y:number){
		this._endNode=new Node(x,y);
	}
// 尋路
	public findPath():Array<Node>{
		return this._astar.findPath(this);
	}
// 網格寬度
	public get width(){
		return this._width;
	}
// 網格高度
	public get height(){
		return this._height;
	}
// 獲得起點
	public get startNode(){
		return this._startNode;
	}
// 獲得終點
	public get endNode(){
		return this._endNode;
	}
// 坐標點是否在網格內
	public isInside(x:number,y:number):boolean{
		return (x>=0 && x<this._width) && (y>=0 && y<this._height);
	}
// 相鄰節點 Always:0,Never:1,IfAtMostOneObstancle:2,OnlyWhenNoObstacels:3,
	public getNeighbors(node:Node,diagonallMovement:number):Array<Node>
	{
		var x=node.x,
		y=node.y,
		neighbors=Array<Node>(),
//上下左右
		s0=false,s1=false,
		s2=false,s3=false,
//斜方向
		d0=false,d1=false,
		d2=false,d3=false,
		nodes=this._nodes;
// 上
		if(this.isWallableAt(x,y-1)){
			neighbors.push(nodes[x][y-1]);
			s0=true;
		}
// 右
		if(this.isWallableAt(x+1,y)){
			neighbors.push(nodes[x+1][y]);
			s1=true;
		}
// 下
		if(this.isWallableAt(x,y+1)){
			neighbors.push(nodes[x][y+1]);
			s2=true;
		}
// 左
		if(this.isWallableAt(x-1,y)){
			neighbors.push(nodes[x-1][y]);
			s3=true;
		}
		if(diagonallMovement==1){
			return neighbors;
		}
		if(diagonallMovement==3){
			d0=s3 && s0;
			d1=s0 && s1;
			d2=s1 && s2;
			d3=s2 && s3;
		}else if(diagonallMovement==2){
			d0=s3 || s0;
			d1=s0 || s1;
			d2=s1 || s2;
			d3=s2 || s3;
		}else if(diagonallMovement==0){
			d0=true;
			d1=true;
			d2=true;
			d3=true;
		}
// 左上
		if(d0 && this.isWallableAt(x-1,y-1)){
			neighbors.push(nodes[x-1][y-1]);
		}
// 右上
		if(d1 && this.isWallableAt(x+1,y-1)){
			neighbors.push(nodes[x+1][y+1]);
		}
// 右下
		if(d2 && this.isWallableAt(x+1,y+1)){
			neighbors.push(nodes[x+1][y+1]);
		}
// 左下
		if(d2 && this.isWallableAt(x-1,y+1)){
			neighbors.push(nodes[x-1][y+1]);
		}
		return neighbors;
	}
// 圓滑路徑
	public smoothenPath(path:Array<Node>){
		var len=path.length,
		x0=path[0].x,
		y0=path[0].y,
		x1=path[path.length-1].x,
		y1=path[path.length-1].y,
		sx:number,sy:number,
		ex:number,ey:number,
		newPath:Array<Node>,
		i:number,j:number,coord:Node,line:Array<Node>,testCoord:Node,blocked:boolean;
		sx=x0;
		sy=y0;
		newPath=[new Node(sx,sy)];
		for(i=2;i<path.length;++i){
			coord=path[i];
			ex=coord.x;
			ey=coord.y;
			line=this.interpolate(sx,sy,ex,ey);
			blocked=false;
			for(j=1;j<line.length;++j){
				testCoord=line[j];
				if(!this.isWallableAt(testCoord.x,testCoord.y)){
					blocked=true;
					break;
				}
			}
			if(blocked){
				var lastValidCoord=path[i-1];
				newPath.push(lastValidCoord);
				sx=lastValidCoord.x;
				sy=lastValidCoord.y;
			}
		}
		newPath.push(new Node(x1,y1));
		return newPath;
	}

	private interpolate(x0:number,y0:number,x1:number,y1:number){
		var line:Array<Node>=[],
		sx:number,sy:number,dx:number,dy:number,err:number,e2:number;
		dx=Math.abs(x1-x0);
		dy=Math.abs(y1-y0);
		sx=(x0<x1) ?1:-1;
		sy=(y0<y1) ?1:-1;
		err=dx-dy;
		while(true){
			line.push(new Node(x0,y0));
			if(x0==x1 && y0==y1){
				break;
			}
			e2=2*err;
			if(e2>-dy){
				err=err-dy;
				x0=x0+sx;
			}
			if(e2<dx){
				err=err+dx;
				y0=y0+sy;
			}
		}
		return line;
	}
}