//
//  ViewController.swift
//  ARR2D2
//
//  Created by Charlie Barber on 7/7/21.
//

import UIKit
import Metal
import MetalKit
import ARKit

extension MTKView : RenderDestinationProvider {
}

class ViewController: UIViewController, MTKViewDelegate, ARSessionDelegate {
    
    var session: ARSession!
    var renderer: Renderer!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // Set the view's delegate
        session = ARSession()
        session.delegate = self
        
        // Set the view to use the default device
        if let view = self.view as? MTKView {
            view.device = MTLCreateSystemDefaultDevice()
            view.backgroundColor = UIColor.clear
            view.delegate = self

            guard view.device != nil else {
                print("Metal is not supported on this device")
                return
            }

            // Configure the renderer to draw to the view
            renderer = Renderer(session: session, metalDevice: view.device!, renderDestination: view)

            renderer.drawRectResized(size: view.bounds.size)
        }

        let tapGesture = UITapGestureRecognizer(target: self, action: #selector(ViewController.handleTap(gestureRecognize:)))
        view.addGestureRecognizer(tapGesture)
    }
    
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        
        // Create a session configuration
        let configuration = ARWorldTrackingConfiguration()
        
//        configuration.planeDetection = [.horizontal]

        // Run the view's session
        session.run(configuration)
    }
    
    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        
        // Pause the view's session
        session.pause()
    }
    
    @objc
    func handleTap(gestureRecognize: UITapGestureRecognizer) {
        // Create anchor using the camera's current position
        if let currentFrame = session.currentFrame {

            // Create a transform with a translation of 0.2 meters in front of the camera
            var translation = matrix_identity_float4x4
            var scale = matrix_identity_float4x4
            translation.columns.3.z = -2
            scale.columns.0.x = 0.1
            scale.columns.1.y = 0.1
            scale.columns.2.z = 0.1

            let rotationY = float4x4().rotateYAxis(by: 180)
            let rotationZ = float4x4().rotateZAxis(by: 270)
            let rotation = rotationY * rotationZ
            let tranformation = translation * scale * rotation
            let transform = simd_mul(currentFrame.camera.transform, tranformation)

            // Add a new anchor to the session
            let anchor = ARAnchor(transform: transform)
            session.add(anchor: anchor)
        }
    }
    
    // MARK: - MTKViewDelegate
    
    // Called whenever view changes orientation or layout is changed
    func mtkView(_ view: MTKView, drawableSizeWillChange size: CGSize) {
        renderer.drawRectResized(size: size)
    }
    
//    // Called whenever the view needs to render
    func draw(in view: MTKView) {
        renderer.update()
    }
    
    // MARK: - ARSessionDelegate
    
    func session(_ session: ARSession, didAdd anchors: [ARAnchor]) {
        
        for anchor in anchors {
            guard let planeAnchor = anchor as? ARPlaneAnchor else { return }

            if let currentFrame = session.currentFrame {

                // Create a transform with a translation of 0.2 meters in front of the camera
                var translation = matrix_identity_float4x4
                var scale = matrix_identity_float4x4
                translation.columns.3.x = -0.077392
                translation.columns.3.y = -1.280197
                translation.columns.3.z = -1.772298
                scale.columns.0.x = 0.1
                scale.columns.1.y = 0.1
                scale.columns.2.z = 0.1

                let rotationY = float4x4().rotateYAxis(by: 180)
                let rotationZ = float4x4().rotateZAxis(by: 270)
                let rotation = rotationY * rotationZ
                let tranformation = translation * scale * rotation
                let transform = simd_mul(currentFrame.camera.transform, tranformation)
                
                let anchoredObject = ARAnchor(transform: transform)
                session.add(anchor: anchoredObject)
            }
            
            
        }
    }
        
    func session(_ session: ARSession, didFailWithError error: Error) {
        // Present an error message to the user
        
    }
    
    func sessionWasInterrupted(_ session: ARSession) {
        // Inform the user that the session has been interrupted, for example, by presenting an overlay
        
    }
    
    func sessionInterruptionEnded(_ session: ARSession) {
        // Reset tracking and/or remove existing anchors if consistent tracking is required
        
    }
}