Caps-iOS/Caps/Camera/ContentViewModel.swift

import CoreImage
import AVFoundation
import UIKit

class ContentViewModel: ObservableObject {

    @Published var error: Error?
    @Published var frame: CGImage?
    @Published var image: UIImage?

    private var cameraManager: CameraManager {
        .shared
    }
    private var frameManager: FrameManager {
        .shared
    }

    init() {
        setupSubscriptions()
    }
    
    func setupSubscriptions() {
        frameManager.image = nil
        frameManager.current = nil

        cameraManager.$error
            .receive(on: RunLoop.main)
            .map { $0 }
            .assign(to: &$error)

        frameManager.$current
            .receive(on: RunLoop.main)
            .compactMap { buffer in
                guard let image = CGImage.create(from: buffer) else {
                    return nil
                }

                let ciImage = CIImage(cgImage: image)
                return FrameManager.shared.context.createCGImage(ciImage, from: ciImage.extent)
            }
            .assign(to: &$frame)

        frameManager.$image
            .receive(on: RunLoop.main)
            .assign(to: &$image)
    }

    func endCapture() {
        cameraManager.stopVideoCaptureSession()
    }

    func startCapture() {
        cameraManager.startVideoCapture()
    }

    func captureImage() {
        cameraManager.capturePhoto(delegate: frameManager)
    }

    func continuouslyFocusOnMiddle() {
        cameraManager.continuouslyFocusOnMiddle()
    }
}