//
//  CameraManager+PhotoOutput.swift of MijickCamera
//
//  Created by Tomasz Kurylik. Sending ❤️ from Kraków!
//    - Mail: tomasz.kurylik@mijick.com
//    - GitHub: https://github.com/FulcrumOne
//    - Medium: https://medium.com/@mijick
//
//  Copyright ©2024 Mijick. All rights reserved.


import AVKit

@MainActor class CameraManagerPhotoOutput: NSObject {
    private(set) var parent: CameraManager!
    private(set) var output: AVCapturePhotoOutput = .init()
}

// MARK: Setup
extension CameraManagerPhotoOutput {
    func setup(parent: CameraManager) throws(MCameraError) {
        self.parent = parent
        try self.parent.captureSession.add(output: output)
    }
}


// MARK: - CAPTURE PHOTO



// MARK: Capture
extension CameraManagerPhotoOutput {
    func capture() {
        guard let parent else {
            print("CameraManagerPhotoOutput: parent is nil, cannot capture")
            return
        }
        
        configureOutput()
        
        // Check if we should disable iOS Retina Flash (when using custom screen flash from SwiftUI layer)
        let disableBuiltInFlash = parent.attributes.screenFlashColor != nil &&
                                   parent.attributes.cameraPosition == .front &&
                                   parent.attributes.flashMode != .off
        
        let settings = getPhotoOutputSettings(disableFlash: disableBuiltInFlash)
        output.capturePhoto(with: settings, delegate: self)
        parent.cameraMetalView.performImageCaptureAnimation()
    }
}
private extension CameraManagerPhotoOutput {
    func getPhotoOutputSettings(disableFlash: Bool) -> AVCapturePhotoSettings {
        let settings = AVCapturePhotoSettings()
        
        // When using custom screen flash for front camera, disable iOS's built-in flash
        // to prevent double-flash (our custom flash + iOS Retina Flash)
        if disableFlash {
            settings.flashMode = .off
        } else {
            // For back camera, use the requested flash mode if supported
            let desiredFlashMode = parent.attributes.flashMode.toDeviceFlashMode()
            if output.supportedFlashModes.contains(desiredFlashMode) {
                settings.flashMode = desiredFlashMode
            } else {
                settings.flashMode = .off
            }
        }
        
        return settings
    }
    func configureOutput() {
        guard let connection = output.connection(with: .video), connection.isVideoMirroringSupported else { return }

        connection.isVideoMirrored = parent.attributes.mirrorOutput ? parent.attributes.cameraPosition != .front : parent.attributes.cameraPosition == .front
        connection.videoOrientation = parent.attributes.deviceOrientation
    }
}

// MARK: Receive Data
extension CameraManagerPhotoOutput: @preconcurrency AVCapturePhotoCaptureDelegate {
    func photoOutput(_ output: AVCapturePhotoOutput, didFinishProcessingPhoto photo: AVCapturePhoto, error: (any Error)?) {
        guard let imageData = photo.fileDataRepresentation(),
              let ciImage = CIImage(data: imageData)
        else { return }

        let capturedCIImage = prepareCIImage(ciImage, parent.attributes.cameraFilters)
        let capturedCGImage = prepareCGImage(capturedCIImage)
        let capturedUIImage = prepareUIImage(capturedCGImage)
        let capturedMedia = MCameraMedia(data: capturedUIImage)

        parent.setCapturedMedia(capturedMedia)
    }
}
private extension CameraManagerPhotoOutput {
    func prepareCIImage(_ ciImage: CIImage, _ filters: [CIFilter]) -> CIImage {
        ciImage.applyingFilters(filters)
    }
    func prepareCGImage(_ ciImage: CIImage) -> CGImage? {
        CIContext().createCGImage(ciImage, from: ciImage.extent)
    }
    func prepareUIImage(_ cgImage: CGImage?) -> UIImage? {
        guard let cgImage else { return nil }

        let frameOrientation = getFixedFrameOrientation()
        let orientation = UIImage.Orientation(frameOrientation)
        let uiImage = UIImage(cgImage: cgImage, scale: 1.0, orientation: orientation)
        return uiImage
    }
}
private extension CameraManagerPhotoOutput {
    func getFixedFrameOrientation() -> CGImagePropertyOrientation {
        guard UIDevice.current.orientation != parent.attributes.deviceOrientation.toDeviceOrientation() else { return parent.attributes.frameOrientation }

        return switch (parent.attributes.deviceOrientation, parent.attributes.cameraPosition) {
            case (.portrait, .front): .left
            case (.portrait, .back): .right
            case (.landscapeLeft, .back): .down
            case (.landscapeRight, .back): .up
            case (.landscapeLeft, .front) where parent.attributes.mirrorOutput: .up
            case (.landscapeLeft, .front): .upMirrored
            case (.landscapeRight, .front) where parent.attributes.mirrorOutput: .down
            case (.landscapeRight, .front): .downMirrored
            default: .right
        }
    }
}