/*

 Copyright (C) 2018 Apple Inc. All Rights Reserved.

 See LICENSE.txt for this sample’s licensing information

 Abstract:

 SceneKit node wrapper that estimates an object's final placement

 */

import Foundation

import ARKit

class PreviewNode: SCNNode {

    // Saved positions that help smooth the movement of the preview

    var lastPositionOnPlane: float3?

    var lastPosition: float3?

    // Use average of recent positions to avoid jitter.

    private var recentPreviewNodePositions: [float3] = []

    // MARK: - Initialization

    override init() {

        super.init()

    }

    convenience init(node: SCNNode) {

        self.init()

        opacity = 0.5

        addChildNode(node)

    }

    required init?(coder aDecoder: NSCoder) {

        fatalError("init(coder:) has not been implemented")

    }

    // MARK: - Appearence

    func update(for position: float3, planeAnchor: ARPlaneAnchor?, camera: ARCamera?) {

        lastPosition = position

        if planeAnchor != nil {

            lastPositionOnPlane = position

        }

        updateTransform(for: position, camera: camera)

    }

    // MARK: - Private

    private func updateTransform(for position: float3, camera: ARCamera?) {

        // Add to the list of recent positions.

        recentPreviewNodePositions.append(position)

        // Remove anything older than the last 8 positions.

        recentPreviewNodePositions.keepLast(8)

        // Move to average of recent positions to avoid jitter.

        if let average = recentPreviewNodePositions.average {

            simdPosition = average

        }

    }

}