class GameScene: SKScene, UIGestureRecognizerDelegate {
var SceneCamera = SKCameraNode()

var LastLocation = CGPoint()

@objc func handlePanFrom(recognizer: UIPanGestureRecognizer) {
    var translation = recognizer.translation(in: recognizer.view!)
    translation = CGPoint(x: translation.x + LastLocation.x, y: -translation.y + LastLocation.y)
    camera?.position = CGPoint(x: position.x - translation.x, y: position.y - translation.y)

    if recognizer.state == .ended {
        LastLocation = translation
    }
}

@objc func handlePinchFrom(recognizer: UIPinchGestureRecognizer) {

    var anchorPoint = recognizer.location(in: recognizer.view)
    anchorPoint = self.convertPoint(fromView: anchorPoint)

    let anchorPointInCamera = camera?.convert(anchorPoint, from: self)
    camera?.setScale((camera?.xScale)! / (recognizer.scale))

    let CameraAnchorPointInScene = self.convert(anchorPointInCamera!, from: camera!)
    let TranslationOfAnchorInScene = (x: anchorPoint.x - CameraAnchorPointInScene.x, y: anchorPoint.y - CameraAnchorPointInScene.y)

    camera?.position = CGPoint(x: (camera?.position.x)! + TranslationOfAnchorInScene.x, y: (camera?.position.y)! + TranslationOfAnchorInScene.y)
    recognizer.scale = 1.0

    setCameraConstraints()
}

override func didMove(to view: SKView) {

    // Setup camera control
    SceneCamera.position = CGPoint(x: (scene?.frame.midX)!, y: (scene?.frame.midY)!)

    let playableAreaScaleForIphoneAndIpadPro =  (view.bounds.size.height) / (scene?.frame.height)!
    SceneCamera.setScale(1/playableAreaScaleForIphoneAndIpadPro)

    self.addChild(SceneCamera)
    self.camera = SceneCamera

    setCameraConstraints()

    // Camera Control: Pinch(Zoom)
    let PinchGesture = UIPinchGestureRecognizer(target: self, action: #selector(handlePinchFrom(recognizer:)))
    PinchGesture.delegate = self
    self.view?.addGestureRecognizer(PinchGesture)

    let PanGesture = UIPanGestureRecognizer(target: self, action: #selector(handlePanFrom(recognizer:)))
    PanGesture.minimumNumberOfTouches = 2
    PanGesture.delegate = self
    self.view?.addGestureRecognizer(PanGesture)
}

func setCameraConstraints() {

    guard let camera = camera else { return }


    let scaledSize = CGSize(width: size.width * camera.xScale, height: size.height * camera.yScale)


    let boardContentRect = scene?.frame

    let xInset = min((scaledSize.width / 2) - 0.0, (boardContentRect?.width)! / 2)
    let yInset = min((scaledSize.height / 2) - 0.0, (boardContentRect?.height)! / 2)

    let insetContentRect = boardContentRect?.insetBy(dx: xInset, dy: yInset)

    let xRange = SKRange(lowerLimit: (insetContentRect?.minX)!, upperLimit: (insetContentRect?.maxX)!)
    let yRange = SKRange(lowerLimit: (insetContentRect?.minY)!, upperLimit: (insetContentRect?.maxY)!)

    let levelEdgeConstraint = SKConstraint.positionX(xRange, y: yRange)
    levelEdgeConstraint.referenceNode = scene

    camera.constraints = [levelEdgeConstraint]
}

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
    return true
}
}