var DegToRad = require('../../math/DegToRad'); 
var GetBoolean = require('../../tweens/builders/GetBoolean'); 
var GetValue = require('../../utils/object/GetValue'); 
var TWEEN_CONST = require('../../tweens/tween/const'); 
var Vector2 = require('../../math/Vector2'); 
var PathFollower = { 
path: null ,
rotateToPath: false ,
pathRotationOffset: 0,
pathOffset: null ,
pathVector: null ,
pathDelta: null ,
pathTween: null ,
pathConfig: null ,
_prevDirection: TWEEN_CONST.PLAYING_FORWARD,
setPath: function (path, config){ 
if (config === undefined) { 
config = this.pathConfig; 
} 
var tween = this.pathTween; 
if (tween && tween.isPlaying()) { 
tween.stop(); 
} 
this.path = path; 
if (config) { 
this.startFollow(config); 
} 
return this; 
} 
,
setRotateToPath: function (value, offset){ 
if (offset === undefined) { 
offset = 0; 
} 
this.rotateToPath = value; 
this.pathRotationOffset = offset; 
return this; 
} 
,
isFollowing: function (){ 
var tween = this.pathTween; 
return (tween && tween.isPlaying()); 
} 
,
startFollow: function (config, startAt){ 
if (config === undefined) { 
config = { 
}
; 
} 
if (startAt === undefined) { 
startAt = 0; 
} 
var tween = this.pathTween; 
if (tween && tween.isPlaying()) { 
tween.stop(); 
} 
if (typeof config === 'number') { 
config = { 
duration: config}
; 
} 
config.from = GetValue(config, 'from', 0); 
config.to = GetValue(config, 'to', 1); 
var positionOnPath = GetBoolean(config, 'positionOnPath', false ); 
this.rotateToPath = GetBoolean(config, 'rotateToPath', false ); 
this.pathRotationOffset = GetValue(config, 'rotationOffset', 0); 
var seek = GetValue(config, 'startAt', startAt); 
if (seek) { 
config.onStart = function (tween){ 
var tweenData = tween.data[0]; 
tweenData.progress = seek; 
tweenData.elapsed = tweenData.duration * seek; 
var v = tweenData.ease(tweenData.progress); 
tweenData.current = tweenData.start + ((tweenData.end - tweenData.start) * v); 
_AN_Read_target('target', tweenData)[tweenData.key] = tweenData.current; 
} 
; 
} 
if (!this.pathOffset) { 
this.pathOffset = new Vector2(this.x, this.y); 
} 
if (!this.pathVector) { 
this.pathVector = new Vector2(); 
} 
if (!this.pathDelta) { 
this.pathDelta = new Vector2(); 
} 
this.pathDelta.reset(); 
this.pathTween = this.scene.sys.tweens.addCounter(config); 
this.path.getStartPoint(this.pathOffset); 
if (positionOnPath) { 
this.x = this.pathOffset.x; 
this.y = this.pathOffset.y; 
} 
this.pathOffset.x = this.x - this.pathOffset.x; 
this.pathOffset.y = this.y - this.pathOffset.y; 
this._prevDirection = TWEEN_CONST.PLAYING_FORWARD; 
if (this.rotateToPath) { 
var nextPoint = this.path.getPoint(0.1); 
this.rotation = Math.atan2(nextPoint.y - this.y, nextPoint.x - this.x) + DegToRad(this.pathRotationOffset); 
} 
this.pathConfig = config; 
return this; 
} 
,
pauseFollow: function (){ 
var tween = this.pathTween; 
if (tween && tween.isPlaying()) { 
tween.pause(); 
} 
return this; 
} 
,
resumeFollow: function (){ 
var tween = this.pathTween; 
if (tween && tween.isPaused()) { 
tween.resume(); 
} 
return this; 
} 
,
stopFollow: function (){ 
var tween = this.pathTween; 
if (tween && tween.isPlaying()) { 
tween.stop(); 
} 
return this; 
} 
,
pathUpdate: function (){ 
var tween = this.pathTween; 
if (tween) { 
var tweenData = tween.data[0]; 
var pathDelta = this.pathDelta; 
var pathVector = this.pathVector; 
pathDelta.copy(pathVector).negate(); 
if (tweenData.state === TWEEN_CONST.COMPLETE) { 
this.path.getPoint(1, pathVector); 
pathDelta.add(pathVector); 
pathVector.add(this.pathOffset); 
this.setPosition(pathVector.x, pathVector.y); 
return ; 
} 
 else if (tweenData.state !== TWEEN_CONST.PLAYING_FORWARD && tweenData.state !== TWEEN_CONST.PLAYING_BACKWARD) { 
return ; 
} 
this.path.getPoint(tween.getValue(), pathVector); 
pathDelta.add(pathVector); 
pathVector.add(this.pathOffset); 
var oldX = this.x; 
var oldY = this.y; 
this.setPosition(pathVector.x, pathVector.y); 
var speedX = this.x - oldX; 
var speedY = this.y - oldY; 
if (speedX === 0 && speedY === 0) { 
return ; 
} 
if (tweenData.state !== this._prevDirection) { 
this._prevDirection = tweenData.state; 
return ; 
} 
if (this.rotateToPath) { 
this.rotation = Math.atan2(speedY, speedX) + DegToRad(this.pathRotationOffset); 
} 
} 
} 
}
; 
module.exports = PathFollower;