High Resolution Photo Capture Enhancements

import AVFoundation
import Photos
import UIKit

class HighResPhotoCaptureController: NSObject {
    let session = AVCaptureSession()
    let photoOutput = AVCapturePhotoOutput()
    var currentProxyURL: URL?

    func configure() throws {
        session.beginConfiguration()
        session.sessionPreset = .photo

        guard let device = AVCaptureDevice.default(.builtInWideAngleCamera,
                                                   for: .video,
                                                   position: .back),
              let input = try? AVCaptureDeviceInput(device: device),
              session.canAddInput(input) else {
            throw CameraError.deviceUnavailable
        }
        session.addInput(input)

        photoOutput.maxPhotoQualityPrioritization = .quality
        photoOutput.isResponsiveCaptureEnabled = true
        photoOutput.isFastCapturePrioritizationEnabled = true  // iOS 27 + iPhone 16/17
        photoOutput.isDeferredPhotoDeliveryEnabled = true

        guard session.canAddOutput(photoOutput) else {
            throw CameraError.outputUnavailable
        }
        session.addOutput(photoOutput)

        // Select largest supported dimensions from the active format
        if let largestDimensions = device.activeFormat
            .supportedMaxPhotoDimensions.last {
            photoOutput.maxPhotoDimensions = largestDimensions
        }

        session.commitConfiguration()

        // Pre-allocate resources for 48MP quality captures
        let prepareSettings = AVCapturePhotoSettings()
        prepareSettings.maxPhotoDimensions = photoOutput.maxPhotoDimensions
        prepareSettings.photoQualityPrioritization = .quality
        photoOutput.setPreparedPhotoSettingsArray([prepareSettings]) { prepared, error in
            if prepared {
                print("Resources pre-allocated for high-res capture")
            }
        }
    }

    func capturePhoto() {
        let settings = AVCapturePhotoSettings()
        settings.maxPhotoDimensions = photoOutput.maxPhotoDimensions
        settings.photoQualityPrioritization = .quality
        photoOutput.capturePhoto(with: settings, delegate: self)
    }

    enum CameraError: Error {
        case deviceUnavailable
        case outputUnavailable
    }
}

extension HighResPhotoCaptureController: AVCapturePhotoCaptureDelegate {
    // Called immediately after shutter — observe expected processing time
    func photoOutput(_ output: AVCapturePhotoOutput,
                     didCapturePhotoFor resolvedSettings: AVCaptureResolvedPhotoSettings) {
        let range = resolvedSettings.photoProcessingTimeRange
        print("Capture done. Processing: \(range.start.seconds)s – \(CMTimeAdd(range.start, range.duration).seconds)s")
    }

    // Deferred processing: receive lightweight proxy immediately
    func photoOutput(_ output: AVCapturePhotoOutput,
                     didFinishCapturingDeferredPhotoProxy deferredPhotoProxy: AVCaptureDeferredPhotoProxy?,
                     error: Error?) {
        guard let proxy = deferredPhotoProxy else { return }
        PHPhotoLibrary.shared().performChanges({
            let request = PHAssetCreationRequest.forAsset()
            request.addResource(with: .photo,
                                data: proxy.fileDataRepresentation()!,
                                options: nil)
        }) { success, error in
            print("Proxy saved to library, final quality will be deferred: \(success)")
        }
    }

    // Fallback: non-deferred delivery
    func photoOutput(_ output: AVCapturePhotoOutput,
                     didFinishProcessingPhoto photo: AVCapturePhoto,
                     error: Error?) {
        guard error == nil,
              let data = photo.fileDataRepresentation() else { return }
        print("Full-res photo ready: \(data.count / 1_000_000) MB")
    }
}