import { Vec2 } from "cc";
//跟随移动
export class Follow2DMove {
    private _pos:Vec2;//起始点
    private _dir:Vec2;//起始方向
    private _rot:number=0;
    private _speed:number;//移动速度
    private _speed_add:number;//移动加速度
    private _ro_speed:number;//转向速度
    private _ro_speed_add:number;//转向加速度
    /***
     * 
     */
    constructor(pos:Vec2,dir:Vec2|number,speed:number=410,speed_add:number=200,ro_speed:number=60,ro_speed_add:number=150){
       this._pos = new Vec2(pos.x,pos.y);
       if(typeof(dir)=='number'){
           this.setRot(dir);
       }else{
           this.setRotByDir(dir);
       }
       this._speed =speed;
       this._speed_add= speed_add;
       this._ro_speed = ro_speed;
       this._ro_speed_add = ro_speed_add;
       //

    }
    public get pos():Vec2{
      return this._pos;
    }
    public get dir():Vec2{
      return this._dir;
    }
    public get rot():number{
      return this._rot;
    }
    public setRotByDir(dir:Vec2){
      this._dir = dir.clone();
      this._rot = this.DirToRot(this._dir);
   }
   public setRot(an:number){
      this._rot = an;
      this._dir = this.RotToDir(this._rot);
   }
   private readonly _dr:number= 180/Math.PI;
   private readonly _rd:number = Math.PI / 180;
   private DirToRot(dir:Vec2):number{
      let radian = dir.signAngle(new Vec2(1,0));
      let angle =-this._dr* radian;
      return(angle);
   }
   private RotToDir(angle:number):Vec2{
      let radian = this._rd *angle;
      let cos = Math.cos(radian);
      let sin = Math.sin(radian);
      return new Vec2(cos, sin).normalize();
   }
   //
   /**本坐标到一个点的方向*/
   private GetDirXY(x:number,y:number):Vec2{
      return new Vec2(x-this._pos.x,y-this._pos.y).normalize();
   }
   private RotationDir(dir:Vec2,angle:number):Vec2
   {
       let radian = Math.PI / 180 *angle;
       let sin = Math.sin(radian);
       var cos = Math.cos(radian);
       var newX = dir.x * cos + dir.y * sin;
       var newY = dir.x * -sin + dir.y * cos;
       dir.x=newX;
       dir.y=newY;
       return dir;
   }
   /**追踪目标x,y*/
   public FollowXY(x:number,y:number,dt:number):void
   {
       let mbdir = this.GetDirXY(x,y);//目标方向
       let vdir = this._dir;//当前方向
       let jd = 180 / Math.PI * vdir.signAngle(mbdir);
       this._ro_speed += this._ro_speed_add*dt;
       let ro = this._ro_speed*dt;
       const jdabs= Math.abs(jd);
       if(ro>=jdabs){
          ro = jd>0 ? -jdabs:jdabs;
       }else{
          ro = jd>0 ? -ro:ro;
       }
       if(ro!=0)this.RotationDir(vdir,ro);
       this.setRotByDir(vdir);
       this.Move(dt);
    }
    private _fame_speed:number=0;
    public get fame_speed():number{
        return this._fame_speed;
    }
    /**向前移动不追踪*/
    public Move(dt:number):void{
      this._speed+=this._speed_add*dt;
      this._fame_speed=this._speed*dt;
      let v = this._dir.clone().multiplyScalar(this._fame_speed);
      this._pos.x+=v.x;
      this._pos.y+=v.y; 
    }
    /**向前移动距离*/
    public MoveDis(dis:number):void{
      let v = this._dir.clone().multiplyScalar(dis);
      this._pos.x+=v.x;
      this._pos.y+=v.y; 
    }
}