import AVFoundation
import CoreGraphics
import UIKit

class FrameManager: NSObject, ObservableObject {

    static let shared = FrameManager()
    
    let context = CIContext()

    @Published var current: CVPixelBuffer?

    @Published var image: UIImage?

    let videoOutputQueue = DispatchQueue(
        label: "de.christophhagen.videoout",
        qos: .userInitiated,
        attributes: [],
        autoreleaseFrequency: .workItem)

    private override init() {
        super.init()

        CameraManager.shared.setVideoDelegate(self, queue: videoOutputQueue)
    }
}

extension FrameManager: AVCaptureVideoDataOutputSampleBufferDelegate {
    
    func captureOutput(
        _ output: AVCaptureOutput,
        didOutput sampleBuffer: CMSampleBuffer,
        from connection: AVCaptureConnection
    ) {
        if let buffer = sampleBuffer.imageBuffer {
            DispatchQueue.main.async {
                self.current = buffer
            }
        }
    }
}

extension FrameManager: AVCapturePhotoCaptureDelegate {

    func photoOutput(_ output: AVCapturePhotoOutput, didFinishProcessingPhoto photo: AVCapturePhoto, error: Error?) {
        let image = convert(photo, error: error)
        DispatchQueue.main.async {
            self.image = image
        }
    }

    private func convert(_ photo: AVCapturePhoto, error: Error?) -> UIImage? {
        guard error == nil else {
            log("PhotoCaptureHandler: \(error!)")
            return nil
        }

        guard let cgImage = photo.cgImageRepresentation() else {
            log("PhotoCaptureHandler: No image captured")
            return nil
        }
        let image = UIImage(cgImage: cgImage, scale: UIScreen.main.scale, orientation: .right)
        guard let masked = image.crop(factor: CameraView.circleCropFactor).circleMasked else {
            log("Could not mask image")
            return nil
        }
        return masked
    }
}