/*

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

 See LICENSE.txt for this sample’s licensing information

 Abstract:

 Main view controller for the Interactive Content sample app.  This file manages the interactions between the view and ARKit.

 */

import UIKit

import SceneKit

import ARKit

class ViewController: UIViewController {

    @IBOutlet var sceneView: ARSCNView!

    @IBOutlet weak var toast: UIVisualEffectView!

    @IBOutlet weak var label: UILabel!

    var chameleon = Chameleon()

    override func viewDidLoad() {

        super.viewDidLoad()

        // Set the view's delegate

        sceneView.delegate = self

        // Set the scene to the view

        sceneView.scene = chameleon

        // The chameleon uses an environment map, so disable built-in lighting

        sceneView.automaticallyUpdatesLighting = false

    }

    override func viewDidAppear(_ animated: Bool) {

        super.viewDidAppear(animated)

        guard ARWorldTrackingConfiguration.isSupported else {

            fatalError("""

                ARKit is not available on this device. For apps that require ARKit

                for core functionality, use the `arkit` key in the key in the

                `UIRequiredDeviceCapabilities` section of the Info.plist to prevent

                the app from installing. (If the app can't be installed, this error

                can't be triggered in a production scenario.)

                In apps where AR is an additive feature, use `isSupported` to

                determine whether to show UI for launching AR experiences.

            """) // For details, see https://developer.apple.com/documentation/arkit

        }

        // Prevent the screen from being dimmed after a while.

        UIApplication.shared.isIdleTimerDisabled = true

        // Start a new session

        startNewSession()

    }

    override func viewWillDisappear(_ animated: Bool) {

        super.viewWillDisappear(animated)

        // Pause the view's session

        sceneView.session.pause()

    }

    func startNewSession() {

        // hide toast

        self.toast.alpha = 0

        self.toast.frame = self.toast.frame.insetBy(dx: 5, dy: 5)

        chameleon.hide()

        // Create a session configuration with horizontal plane detection

        let configuration = ARWorldTrackingConfiguration()

        configuration.planeDetection = .horizontal

        // Run the view's session

        sceneView.session.run(configuration, options: [.removeExistingAnchors, .resetTracking])

    }

    // MARK: - Gesture Recognizers

    @IBAction func didTap(_ recognizer: UITapGestureRecognizer) {

        let location = recognizer.location(in: sceneView)

        // When tapped on the object, call the object's method to react on it

        let sceneHitTestResult = sceneView.hitTest(location, options: nil)

        if !sceneHitTestResult.isEmpty {

            // We only have one content, so we know which node was hit.

            // If the scene contains multiple objects, you would need to check here if the right node was hit

            chameleon.reactToTap(in: sceneView)

            return

        }

        // When tapped on a plane, reposition the content

        let arHitTestResult = sceneView.hitTest(location, types: .existingPlane)

        if !arHitTestResult.isEmpty {

            let hit = arHitTestResult.first!

            chameleon.setTransform(hit.worldTransform)

            chameleon.reactToPositionChange(in: sceneView)

        }

    }

    @IBAction func didPan(_ recognizer: UIPanGestureRecognizer) {

        let location = recognizer.location(in: sceneView)

        // Drag the object on an infinite plane

        let arHitTestResult = sceneView.hitTest(location, types: .existingPlane)

        if !arHitTestResult.isEmpty {

            let hit = arHitTestResult.first!

            chameleon.setTransform(hit.worldTransform)

            if recognizer.state == .ended {

                chameleon.reactToPositionChange(in: sceneView)

            }

        }

    }

}

extension ViewController: ARSCNViewDelegate {

    func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor) {

        if chameleon.isVisible() { return }

        // Unhide the content and position it on the detected plane

        if anchor is ARPlaneAnchor {

            chameleon.setTransform(anchor.transform)

            chameleon.show()

            chameleon.reactToInitialPlacement(in: sceneView)

            DispatchQueue.main.async {

                self.hideToast()

            }

        }

    }

    func renderer(_ renderer: SCNSceneRenderer, updateAtTime time: TimeInterval) {

        chameleon.reactToRendering(in: sceneView)

    }

    func renderer(_ renderer: SCNSceneRenderer, didApplyConstraintsAtTime time: TimeInterval) {

        chameleon.reactToDidApplyConstraints(in: sceneView)

    }

}

extension ViewController: ARSessionObserver {

    func sessionWasInterrupted(_ session: ARSession) {

        showToast("Session was interrupted")

    }

    func sessionInterruptionEnded(_ session: ARSession) {

        startNewSession()

    }

    func session(_ session: ARSession, didFailWithError error: Error) {

        showToast("Session failed: \(error.localizedDescription)")

        startNewSession()

    }

    func session(_ session: ARSession, cameraDidChangeTrackingState camera: ARCamera) {

        var message: String? = nil

        switch camera.trackingState {

        case .notAvailable:

            message = "Tracking not available"

        case .limited(.initializing):

            message = "Initializing AR session"

        case .limited(.excessiveMotion):

            message = "Too much motion"

        case .limited(.insufficientFeatures):

            message = "Not enough surface details"

        case .normal:

            if !chameleon.isVisible() {

                message = "Move to find a horizontal surface"

            }

        default:

            // We are only concerned with the tracking states above.

            message = "Camera changed tracking state"

        }

        message != nil ? showToast(message!) : hideToast()

    }

}

extension ViewController {

    func showToast(_ text: String) {

        label.text = text

        guard toast.alpha == 0 else {

            return

        }

        toast.layer.masksToBounds = true

        toast.layer.cornerRadius = 7.5

        UIView.animate(withDuration: 0.25, animations: {

            self.toast.alpha = 1

            self.toast.frame = self.toast.frame.insetBy(dx: -5, dy: -5)

        })

    }

    func hideToast() {

        UIView.animate(withDuration: 0.25, animations: {

            self.toast.alpha = 0

            self.toast.frame = self.toast.frame.insetBy(dx: 5, dy: 5)

        })

    }

}