import SwiftUI
import AVFoundation

#if os(macOS)
import AppKit

// MARK: - 二维码扫描器视图
struct QRScannerView: NSViewRepresentable {
    let onCodeDetected: (String) -> Void
    
    func makeCoordinator() -> Coordinator {
        Coordinator(onCodeDetected: onCodeDetected)
    }
    
    func makeNSView(context: Context) -> NSView {
        let view = QRScannerHostView()
        view.coordinator = context.coordinator
        context.coordinator.previewLayer = view.previewLayer
        
        // 配置捕获会话
        let session = AVCaptureSession()
        context.coordinator.session = session
        
        guard let device = AVCaptureDevice.default(for: .video),
              let input = try? AVCaptureDeviceInput(device: device) else {
            return view
        }
        
        if session.canAddInput(input) {
            session.addInput(input)
        }
        
        let output = AVCaptureMetadataOutput()
        if session.canAddOutput(output) {
            session.addOutput(output)
            output.setMetadataObjectsDelegate(context.coordinator, queue: .main)
            output.metadataObjectTypes = [.qr]
        }
        
        view.previewLayer.session = session
        view.previewLayer.videoGravity = .resizeAspectFill
        
        // 后台启动会话
        DispatchQueue.global(qos: .userInitiated).async {
            session.startRunning()
        }
        
        return view
    }
    
    func updateNSView(_ nsView: NSView, context: Context) {}
    
    // MARK: - Coordinator
    class Coordinator: NSObject, AVCaptureMetadataOutputObjectsDelegate {
        let onCodeDetected: (String) -> Void
        var session: AVCaptureSession?
        weak var previewLayer: AVCaptureVideoPreviewLayer?
        private var lastDetected: String?
        private var lastDetectedTime: Date = .distantPast
        
        init(onCodeDetected: @escaping (String) -> Void) {
            self.onCodeDetected = onCodeDetected
        }
        
        func metadataOutput(_ output: AVCaptureMetadataOutput, didOutput metadataObjects: [AVMetadataObject], from connection: AVCaptureConnection) {
            guard let metadata = metadataObjects.first as? AVMetadataMachineReadableCodeObject,
                  let code = metadata.stringValue else { return }
            
            // 防抖：同一码 3 秒内不重复触发
            let now = Date()
            if code == lastDetected, now.timeIntervalSince(lastDetectedTime) < 3 {
                return
            }
            lastDetected = code
            lastDetectedTime = now
            
            onCodeDetected(code)
        }
        
        deinit {
            session?.stopRunning()
        }
    }
}

// MARK: - 宿主视图
class QRScannerHostView: NSView {
    let previewLayer = AVCaptureVideoPreviewLayer()
    weak var coordinator: QRScannerView.Coordinator?
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        wantsLayer = true
        // 不在 init 时设置 layer = previewLayer，等 layout 时再添加为 sublayer
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func layout() {
        super.layout()
        if previewLayer.superlayer == nil {
            layer?.addSublayer(previewLayer)
        }
        previewLayer.frame = bounds
    }
}

// MARK: - 扫码弹窗
struct QRScannerDialog: View {
    @ObservedObject var bridge: PlayerBridge
    @Environment(\.dismiss) private var dismiss
    @State private var detectedCode: String?
    @State private var isProcessing = false
    
    var body: some View {
        VStack(spacing: 16) {
            Text(L.scanQRCode)
                .font(.headline)
            
            Text(L.scanHint)
                .font(.caption)
                .foregroundColor(.secondary)
            
            QRScannerView { code in
                detectedCode = code
                handleCode(code)
            }
            .frame(width: 320, height: 240)
            .cornerRadius(8)
            
            if let code = detectedCode {
                VStack(spacing: 8) {
                    Text(L.detectedCode)
                        .font(.caption)
                        .foregroundColor(.secondary)
                    Text(code)
                        .font(.system(.body, design: .monospaced))
                        .lineLimit(2)
                        .multilineTextAlignment(.center)
                }
                .padding(12)
                .background(Color.secondary.opacity(0.1))
                .cornerRadius(8)
            }
            
            HStack {
                Button(L.close) { dismiss() }
                    .keyboardShortcut(.cancelAction)
                Spacer()
            }
        }
        .padding(20)
        .frame(width: 380)
    }
    
    private func handleCode(_ code: String) {
        guard !isProcessing else { return }
        
        // 检查是否为有效 URL
        if let url = URL(string: code), url.scheme == "http" || url.scheme == "https" {
            isProcessing = true
            bridge.addURL(code)
            
            // 延迟关闭弹窗
            DispatchQueue.main.asyncAfter(deadline: .now() + 1.5) {
                dismiss()
            }
        }
    }
}

#endif