import SwiftUI
import AVFoundation
import AudioToolbox
import Combine
import CoreData
import QRCode

// MARK: - 主扫描视图
struct ScannerView: View {
    @StateObject private var scannerViewModel = ScannerViewModel()
    @State private var showPreviewPause = false
    @State private var screenOrientation = UIDevice.current.orientation
    @State private var previewLayer: AVCaptureVideoPreviewLayer?
    @State private var navigateToDetail = false
    @State private var selectedHistoryItem: HistoryItem?
    
    // 图片解码相关状态
    @State private var showImagePicker = false
    @State private var isDecodingImage = false
    @State private var decodedImageCodes: [DetectedCode] = []
    
    var body: some View {
        ZStack {
            // 相机权限检查
            if scannerViewModel.cameraAuthorizationStatus == .authorized {
                // 相机预览层
                CameraPreviewView(session: scannerViewModel.captureSession, previewLayer: $previewLayer)
                    .ignoresSafeArea()
                
                // 扫描界面覆盖层
                ScanningOverlayView(
                    showPreviewPause: showPreviewPause,
                    detectedCodesCount: scannerViewModel.detectedCodes.count,
                    onImageDecode: { showImagePicker = true }
                )
                
                // 条码位置标记覆盖层
                if showPreviewPause && (!scannerViewModel.detectedCodes.isEmpty || !decodedImageCodes.isEmpty) {
                    CodePositionOverlay(
                        detectedCodes: scannerViewModel.detectedCodes + decodedImageCodes,
                        previewLayer: previewLayer,
                        onCodeSelected: handleCodeSelection
                    )
                }
                
                // 测试按钮（调试用）
                if showPreviewPause && (scannerViewModel.detectedCodes.count + decodedImageCodes.count) == 1 {
                    let singleCode = scannerViewModel.detectedCodes.first ?? decodedImageCodes.first
                    if let code = singleCode {
                        TestAutoSelectButton(
                            detectedCode: code,
                            onSelect: handleCodeSelection
                        )
                    }
                }
            } else {
                // 权限未授权时的UI
                CameraPermissionView(
                    authorizationStatus: scannerViewModel.cameraAuthorizationStatus,
                    onRequestPermission: {
                        scannerViewModel.refreshCameraPermission()
                    },
                    onOpenSettings: {
                        scannerViewModel.openSettings()
                    }
                )
            }
        }
        .navigationTitle("扫描器")
        .navigationBarTitleDisplayMode(.inline)
        .navigationBarBackButtonHidden(false)
        .sheet(isPresented: $showImagePicker) {
            ImagePicker(onImageSelected: handleImageDecodeResult)
        }
        .toolbar {
            ToolbarItem(placement: .navigationBarLeading) {
                // 手电筒按钮 - 只在相机权限已授权时显示
                if scannerViewModel.cameraAuthorizationStatus == .authorized && scannerViewModel.isTorchAvailable {
                    Button(action: {
                        logInfo("🔦 用户点击手电筒按钮", className: "ScannerView")
                        
                        // 添加触觉反馈
                        let impactFeedback = UIImpactFeedbackGenerator(style: .medium)
                        impactFeedback.impactOccurred()
                        
                        scannerViewModel.toggleTorch()
                    }) {
                        Image(systemName: scannerViewModel.isTorchOn ? "bolt.fill" : "bolt")
                            .font(.system(size: 18, weight: .semibold))
                            .foregroundColor(scannerViewModel.isTorchOn ? .yellow : .blue)
                    }
                }
            }
            
            ToolbarItem(placement: .navigationBarTrailing) {
                // 重新扫描按钮 - 只在预览暂停状态时显示
                if showPreviewPause {
                    Button(action: {
                        logInfo("🔄 用户点击工具栏重新扫描按钮", className: "ScannerView")
                        
                        // 添加触觉反馈
                        let impactFeedback = UIImpactFeedbackGenerator(style: .medium)
                        impactFeedback.impactOccurred()
                        
                        resetToScanning()
                    }) {
                        HStack(spacing: 6) {
                            Image(systemName: "arrow.clockwise")
                                .font(.system(size: 16, weight: .semibold))
                            
                            Text("rescan_button".localized)
                                .font(.system(size: 14, weight: .medium))
                        }
                        .foregroundColor(.blue)
                    }
                }
            }
        }
        .onAppear {
            // 只有在相机权限已授权时才启动扫描
            if scannerViewModel.cameraAuthorizationStatus == .authorized {
                scannerViewModel.startScanning()
            }
        }
        .onDisappear {
            scannerViewModel.stopScanning()
            // 确保退出时关闭手电筒
            if scannerViewModel.isTorchOn {
                scannerViewModel.turnOffTorch()
            }
        }
        .alert("scan_error_title".localized, isPresented: $scannerViewModel.showAlert) {
            Button("OK") { }
        } message: {
            Text("scan_error_message".localized)
        }
        .onReceive(scannerViewModel.$detectedCodes) { codes in
            handleDetectedCodes(codes)
        }
        .onReceive(scannerViewModel.$cameraAuthorizationStatus) { status in
            if status == .authorized {
                logInfo("🎯 相机权限已授权，启动扫描", className: "ScannerView")
                scannerViewModel.startScanning()
            }
        }
        .onReceive(NotificationCenter.default.publisher(for: UIDevice.orientationDidChangeNotification)) { _ in
            handleOrientationChange()
        }
        .background(
            NavigationLink(
                destination: Group {
                    if let historyItem = selectedHistoryItem {
                        QRCodeDetailView(historyItem: historyItem)
                            .onDisappear {
                                // 从详情页返回时，重新开始扫描
                                logInfo("🔄 从详情页返回，重新开始扫描", className: "ScannerView")
                                resetToScanning()
                            }
                    }
                },
                isActive: $navigateToDetail
            ) {
                EmptyView()
            }
        )
    }
    
    // MARK: - 私有方法
    
    private func handleDetectedCodes(_ codes: [DetectedCode]) {
        guard !codes.isEmpty else { return }
        
        logInfo("检测到条码数量: \(codes.count)", className: "ScannerView")
        
        if codes.count == 1 {
            logInfo("单个条码，准备自动选择", className: "ScannerView")
            pauseForPreview()
            autoSelectSingleCode(code: codes[0])
        } else {
            logInfo("多个条码，等待用户选择", className: "ScannerView")
            pauseForPreview()
        }
    }
    
    private func handleOrientationChange() {
        screenOrientation = UIDevice.current.orientation
        logInfo("Screen orientation changed to: \(screenOrientation.rawValue)", className: "ScannerView")
    }
    
    private func handleCodeSelection(_ selectedCode: DetectedCode) {
        logInfo("🎯 ScannerView 收到条码选择回调", className: "ScannerView")
        logInfo("  选择的条码ID: \(selectedCode.id)", className: "ScannerView")
        logInfo("  选择的条码类型: \(selectedCode.type)", className: "ScannerView")
        logInfo("  选择的条码内容: \(selectedCode.content)", className: "ScannerView")
        logInfo("  选择的条码位置: \(selectedCode.bounds)", className: "ScannerView")
        
        // 停止扫描功能，避免在详情页面继续扫描
        scannerViewModel.stopScanning()
        logInfo("🛑 已停止扫描功能", className: "ScannerView")
        
        // 创建 HistoryItem 并保存到 Core Data
        let historyItem = createHistoryItem(from: selectedCode)
        
        // 延迟一小段时间确保扫描完全停止后再跳转
        DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) {
            // 设置选中的历史记录项并导航到详情页
            self.selectedHistoryItem = historyItem
            self.navigateToDetail = true
        }
        
        // 发送通知（保持向后兼容）
        let formattedResult = "类型: \(selectedCode.type)\n内容: \(selectedCode.content)"
        logInfo("  格式化结果: \(formattedResult)", className: "ScannerView")
        NotificationCenter.default.post(name: .scannerDidScanCode, object: formattedResult)
    }
    
    private func createHistoryItem(from detectedCode: DetectedCode) -> HistoryItem {
        let context = CoreDataManager.shared.container.viewContext
        let historyItem = HistoryItem(context: context)
        
        historyItem.id = UUID()
        historyItem.content = detectedCode.content
        historyItem.dataType = DataType.qrcode.rawValue
        historyItem.dataSource = DataSource.scanned.rawValue
        historyItem.createdAt = Date()
        historyItem.isFavorite = false
        
        // 根据条码类型设置相应的类型字段
        if detectedCode.type.lowercased().contains("qr") || detectedCode.type.lowercased().contains("二维码") {
            // 尝试解析二维码类型
            let parsedData = QRCodeParser.parseQRCode(detectedCode.content)
            historyItem.qrCodeType = parsedData.type.rawValue
        } else {
            // 条形码类型
            historyItem.barcodeType = detectedCode.type
        }
        
        // 保存到 Core Data
        CoreDataManager.shared.addHistoryItem(historyItem)
        
        logInfo("✅ 已创建并保存历史记录项", className: "ScannerView")
        return historyItem
    }
    
    private func pauseForPreview() {
        showPreviewPause = true
        // 暂停相机功能，防止在预览暂停时继续拍照
        scannerViewModel.pauseCamera()
    }
    
    private func resetToScanning() {
        logInfo("🔄 ScannerView 开始重置到扫描状态", className: "ScannerView")
        
        // 重置UI状态
        showPreviewPause = false
        
        // 重置扫描状态
        scannerViewModel.resetDetection()
        
        // 重置图片解码状态
        resetImageDecodeState()
        
        // 恢复相机功能并重新开始扫描
        scannerViewModel.resumeCamera()
        
        logInfo("✅ ScannerView 已重置到扫描状态", className: "ScannerView")
    }
    
    private func autoSelectSingleCode(code: DetectedCode) {
        logInfo("开始自动选择定时器，条码类型: \(code.type)", className: "ScannerView")
        
        DispatchQueue.main.asyncAfter(deadline: .now() + 1.0) {
            let totalCodes = self.scannerViewModel.detectedCodes.count + self.decodedImageCodes.count
            guard self.showPreviewPause && totalCodes == 1 else {
                logInfo("条件不满足，取消自动选择", className: "ScannerView")
                return
            }
            
            logInfo("条件满足，执行自动选择", className: "ScannerView")
            self.handleCodeSelection(code)
        }
    }
    
    // MARK: - 图片解码相关方法
    
    /// 处理图片解码结果
    private func handleImageDecodeResult(_ image: UIImage) {
        isDecodingImage = true
        decodedImageCodes.removeAll()
        
        logInfo("🔍 开始解码图片", className: "ScannerView")
        
        // 在后台线程进行解码
        DispatchQueue.global(qos: .userInitiated).async { [self] in
            
            // 使用QRCode库检测二维码
            let detected = QRCode.DetectQRCodes(in: image)
            if detected.count > 0 {
                logInfo("✅ 检测到 \(detected.count) 个二维码", className: "ScannerView")
                
                let results = detected.enumerated().map { index, qrCode in
                    DetectedCode(
                        type: "QR Code",
                        content: qrCode.messageString ?? "未知内容",
                        bounds: qrCode.bounds
                    )
                }
                
                DispatchQueue.main.async {
                    self.decodedImageCodes = results
                    self.isDecodingImage = false
                    self.pauseForPreview()
                    logInfo("✅ 图片解码完成，共 \(results.count) 个结果", className: "ScannerView")
                    
                    // 如果只有一个二维码，自动选择并跳转
                    if results.count == 1 {
                        DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) {
                            self.handleCodeSelection(results[0])
                        }
                    }
                }
            } else {
                DispatchQueue.main.async {
                    self.isDecodingImage = false
                    logWarning("❌ 图片中未检测到二维码", className: "ScannerView")
                }
            }
        }
    }
    
    /// 重置图片解码状态
    private func resetImageDecodeState() {
        decodedImageCodes.removeAll()
    }
}

// MARK: - 图片选择器（兼容iOS 15）
struct ImagePicker: UIViewControllerRepresentable {
    let onImageSelected: (UIImage) -> Void
    
    func makeUIViewController(context: Context) -> UIImagePickerController {
        let picker = UIImagePickerController()
        picker.delegate = context.coordinator
        picker.sourceType = .photoLibrary
        picker.allowsEditing = false
        return picker
    }
    
    func updateUIViewController(_ uiViewController: UIImagePickerController, context: Context) {}
    
    func makeCoordinator() -> Coordinator {
        Coordinator(self)
    }
    
    class Coordinator: NSObject, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
        let parent: ImagePicker
        
        init(_ parent: ImagePicker) {
            self.parent = parent
        }
        
        func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
            if let image = info[.originalImage] as? UIImage {
                parent.onImageSelected(image)
            }
            picker.dismiss(animated: true)
        }
        
        func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
            picker.dismiss(animated: true)
        }
    }
}

#if DEBUG
struct ScannerView_Previews: PreviewProvider {
    static var previews: some View {
        NavigationView {
            ScannerView()
        }
    }
}
#endif