import SwiftUI
import AVFoundation

struct CustomCameraView: UIViewControllerRepresentable {
    @Binding var isPresented: Bool
    let onImageCaptured: (UIImage) -> Void
    @Environment(\.presentationMode) private var presentationMode
    
    func makeUIViewController(context: Context) -> CustomCameraViewController {
        let viewController = CustomCameraViewController()
        viewController.delegate = context.coordinator
        return viewController
    }
    
    func updateUIViewController(_ uiViewController: CustomCameraViewController, context: Context) {}
    
    func makeCoordinator() -> Coordinator {
        Coordinator(self)
    }
    
    class Coordinator: NSObject, CustomCameraViewControllerDelegate {
        let parent: CustomCameraView
        
        init(_ parent: CustomCameraView) {
            self.parent = parent
        }
        
        func didCaptureImage(_ image: UIImage) {
            parent.onImageCaptured(image)
            parent.presentationMode.wrappedValue.dismiss()
        }
        
        func didCancel() {
            parent.presentationMode.wrappedValue.dismiss()
        }
    }
}

protocol CustomCameraViewControllerDelegate: AnyObject {
    func didCaptureImage(_ image: UIImage)
    func didCancel()
}

class CustomCameraViewController: UIViewController {
    private var captureSession: AVCaptureSession?
    private var photoOutput: AVCapturePhotoOutput?
    private var previewLayer: AVCaptureVideoPreviewLayer?
    private var captureDevice: AVCaptureDevice?
    
    weak var delegate: CustomCameraViewControllerDelegate?
    
    private lazy var captureButton: UIButton = {
        let button = UIButton(type: .system)
        button.backgroundColor = .white
        button.tintColor = .black
        button.layer.cornerRadius = 35
        button.layer.borderWidth = 5
        button.layer.borderColor = UIColor.lightGray.cgColor
        button.addTarget(self, action: #selector(capturePhoto), for: .touchUpInside)
        return button
    }()
    
    private lazy var closeButton: UIButton = {
        let button = UIButton(type: .system)
        button.setImage(UIImage(systemName: "xmark"), for: .normal)
        button.tintColor = .white
        button.addTarget(self, action: #selector(closeCamera), for: .touchUpInside)
        return button
    }()
    
    private lazy var flipButton: UIButton = {
        let button = UIButton(type: .system)
        button.setImage(UIImage(systemName: "arrow.triangle.2.circlepath.camera"), for: .normal)
        button.tintColor = .white
        button.addTarget(self, action: #selector(switchCamera), for: .touchUpInside)
        return button
    }()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .black
        checkCameraPermissions()
    }
    
    override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()
        // 确保预览层填满整个视图
        previewLayer?.frame = view.bounds
        // 更新视频方向
        if let connection = previewLayer?.connection, connection.isVideoOrientationSupported {
            connection.videoOrientation = .portrait
        }
    }
    
    private func checkCameraPermissions() {
        switch AVCaptureDevice.authorizationStatus(for: .video) {
        case .authorized:
            setupCamera()
        case .notDetermined:
            AVCaptureDevice.requestAccess(for: .video) { [weak self] granted in
                DispatchQueue.main.async {
                    if granted {
                        self?.setupCamera()
                    } else {
                        self?.delegate?.didCancel()
                    }
                }
            }
        default:
            delegate?.didCancel()
        }
    }
    
    private func setupCamera() {
        let session = AVCaptureSession()
        session.sessionPreset = .high
        
        // 修改这里：默认使用后置摄像头
        guard let device = AVCaptureDevice.default(.builtInWideAngleCamera, for: .video, position: .back) else {
            delegate?.didCancel()
            return
        }
        
        captureDevice = device
        
        do {
            let input = try AVCaptureDeviceInput(device: device)
            if session.canAddInput(input) {
                session.addInput(input)
            }
            
            let output = AVCapturePhotoOutput()
            if session.canAddOutput(output) {
                session.addOutput(output)
                photoOutput = output
            }
            
            // 创建预览层并确保填满整个屏幕
            let previewLayer = AVCaptureVideoPreviewLayer(session: session)
            previewLayer.videoGravity = .resizeAspectFill
            previewLayer.frame = view.bounds
            previewLayer.connection?.videoOrientation = .portrait
            
            // 确保预览层填满整个视图
            view.layer.insertSublayer(previewLayer, at: 0)
            self.previewLayer = previewLayer
            
            DispatchQueue.global(qos: .userInitiated).async {
                session.startRunning()
                
                DispatchQueue.main.async {
                    self.setupUI()
                }
            }
            
            captureSession = session
            
        } catch {
            print("Error setting up camera: \(error)")
            delegate?.didCancel()
        }
    }
    
    private func setupUI() {
        view.bringSubviewToFront(closeButton)
        view.bringSubviewToFront(flipButton)
        view.bringSubviewToFront(captureButton)
        
        view.addSubview(closeButton)
        closeButton.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            closeButton.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor, constant: 20),
            closeButton.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 20),
            closeButton.widthAnchor.constraint(equalToConstant: 44),
            closeButton.heightAnchor.constraint(equalToConstant: 44)
        ])
        
        view.addSubview(flipButton)
        flipButton.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            flipButton.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor, constant: -20),
            flipButton.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 20),
            flipButton.widthAnchor.constraint(equalToConstant: 44),
            flipButton.heightAnchor.constraint(equalToConstant: 44)
        ])
        
        view.addSubview(captureButton)
        captureButton.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            captureButton.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            captureButton.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor, constant: -30),
            captureButton.widthAnchor.constraint(equalToConstant: 70),
            captureButton.heightAnchor.constraint(equalToConstant: 70)
        ])
    }
    
    @objc private func capturePhoto() {
        let settings = AVCapturePhotoSettings()
        photoOutput?.capturePhoto(with: settings, delegate: self)
    }
    
    @objc private func closeCamera() {
        delegate?.didCancel()
    }
    
    @objc private func switchCamera() {
        guard let currentInput = captureSession?.inputs.first as? AVCaptureDeviceInput else { return }
        
        let newPosition: AVCaptureDevice.Position = currentInput.device.position == .front ? .back : .front
        
        guard let newDevice = AVCaptureDevice.default(.builtInWideAngleCamera, for: .video, position: newPosition) else { return }
        
        do {
            let newInput = try AVCaptureDeviceInput(device: newDevice)
            captureSession?.beginConfiguration()
            captureSession?.removeInput(currentInput)
            
            if captureSession?.canAddInput(newInput) == true {
                captureSession?.addInput(newInput)
                captureDevice = newDevice
            } else {
                captureSession?.addInput(currentInput)
            }
            
            captureSession?.commitConfiguration()
        } catch {
            print("Error switching camera: \(error)")
        }
    }
}

extension CustomCameraViewController: AVCapturePhotoCaptureDelegate {
    func photoOutput(_ output: AVCapturePhotoOutput, didFinishProcessingPhoto photo: AVCapturePhoto, error: Error?) {
        if let error = error {
            print("Error capturing photo: \(error)")
            return
        }
        
        guard let imageData = photo.fileDataRepresentation(),
              let image = UIImage(data: imageData) else {
            return
        }
        
        let fixedImage = image.fixedOrientation()
        
        DispatchQueue.main.async {
            self.delegate?.didCaptureImage(fixedImage)
        }
    }
}

extension UIImage {
    func fixedOrientation() -> UIImage {
        if imageOrientation == .up {
            return self
        }
        
        UIGraphicsBeginImageContextWithOptions(size, false, scale)
        draw(in: CGRect(origin: .zero, size: size))
        let normalizedImage = UIGraphicsGetImageFromCurrentImageContext() ?? self
        UIGraphicsEndImageContext()
        
        return normalizedImage
    }
}