import SwiftUI
import CoreData
import Photos

struct QRCodeSavedView: View {
    let qrCodeImage: UIImage
    let qrCodeContent: String
    let qrCodeType: QRCodeType
    let styleData: QRCodeStyleData?
    let historyItem: HistoryItem?
    
    @Environment(\.dismiss) private var dismiss
    @EnvironmentObject var coreDataManager: CoreDataManager
    @Environment(\.presentationMode) private var presentationMode
    @State private var shouldReturnToRoot = false
    @State private var shouldPopToRoot = false
    @State private var showingShareSheet = false
    @State private var showingAlert = false
    @State private var alertMessage = ""
    @State private var isSavingToPhotos = false
    @State private var showingImageComposer = false
    @State private var showingBackgroundImagePicker = false
    @State private var selectedBackgroundImage: UIImage?
    
    // 用于保存图片的辅助类
    private let photoSaver = PhotoSaver()
    
    var body: some View {
        VStack(spacing: 30) {
            // 二维码图片
            qrCodeImageView
            
            // 操作按钮
            actionButtonsSection
            
            Spacer()
        }
        .padding()
        .navigationTitle("二维码已保存")
        .navigationBarTitleDisplayMode(.inline)
        .toolbar {
                            ToolbarItem(placement: .navigationBarTrailing) {
                    Button("返回主页") {
                        // 返回到ContentView，清除导航栈
                        shouldPopToRoot = true
                    }
                }
        }
        .sheet(isPresented: $showingShareSheet) {
            ShareSheet(activityItems: [qrCodeImage])
        }
        .alert("提示", isPresented: $showingAlert) {
            Button("确定") { }
        } message: {
            Text(alertMessage)
        }
        .background(
            NavigationLink(
                destination: ContentView()
                    .navigationBarBackButtonHidden(true)
                    .navigationBarHidden(true),
                isActive: $shouldPopToRoot
            ) {
                EmptyView()
            }
        )
        .sheet(isPresented: $showingBackgroundImagePicker) {
            ImagePicker(
                onImageSelected: { image in
                    selectedBackgroundImage = image
                    showingImageComposer = true
                },
                shouldProcessImage: false
            )
        }
        .sheet(isPresented: $showingImageComposer) {
            if let backgroundImage = selectedBackgroundImage {
                ImageComposerView(qrCodeImage: qrCodeImage, backgroundImage: backgroundImage)
            }
        }
    }
    
    // MARK: - 二维码图片视图
    private var qrCodeImageView: some View {
        VStack(spacing: 16) {
            Image(uiImage: qrCodeImage)
                .resizable()
                .aspectRatio(contentMode: .fit)
                .frame(width: 300, height: 300)
                .cornerRadius(16)
                .shadow(radius: 10)
            
            Text("扫描此二维码")
                .font(.headline)
                .foregroundColor(.secondary)
        }
    }
    
    // MARK: - 操作按钮区域
    private var actionButtonsSection: some View {
        HStack(spacing: 12) {
            // 分享按钮
            Button(action: {
                showingShareSheet = true
            }) {
                VStack(spacing: 8) {
                    Image(systemName: "square.and.arrow.up")
                        .font(.title2)
                    
                    Text("分享")
                        .font(.caption)
                        .fontWeight(.medium)
                }
                .frame(maxWidth: .infinity)
                .padding(.vertical, 16)
                .background(Color.blue)
                .foregroundColor(.white)
                .cornerRadius(12)
            }
            
            // 保存到相册按钮
            Button(action: saveToPhotos) {
                VStack(spacing: 8) {
                    if isSavingToPhotos {
                        ProgressView()
                            .scaleEffect(0.8)
                            .foregroundColor(.white)
                    } else {
                        Image(systemName: "photo")
                            .font(.title2)
                    }
                    
                    Text(isSavingToPhotos ? "保存中..." : "保存")
                        .font(.caption)
                        .fontWeight(.medium)
                }
                .frame(maxWidth: .infinity)
                .padding(.vertical, 16)
                .background(Color.green)
                .foregroundColor(.white)
                .cornerRadius(12)
            }
            .disabled(isSavingToPhotos)
            
            // 添加到图片按钮
            Button(action: addToPhotos) {
                VStack(spacing: 8) {
                    Image(systemName: "plus.rectangle.on.folder")
                        .font(.title2)
                    
                    Text("添加到图片")
                        .font(.caption)
                        .fontWeight(.medium)
                }
                .frame(maxWidth: .infinity)
                .padding(.vertical, 16)
                .background(Color.orange)
                .foregroundColor(.white)
                .cornerRadius(12)
            }
        }
    }
    
    // MARK: - 保存到相册
    private func saveToPhotos() {
        isSavingToPhotos = true
        
        // 检查相册权限
        let status = PHPhotoLibrary.authorizationStatus()
        
        switch status {
        case .authorized, .limited:
            saveImageToPhotos()
        case .notDetermined:
            PHPhotoLibrary.requestAuthorization { newStatus in
                DispatchQueue.main.async {
                    if newStatus == .authorized || newStatus == .limited {
                        self.saveImageToPhotos()
                    } else {
                        self.showPermissionAlert()
                    }
                    self.isSavingToPhotos = false
                }
            }
        case .denied, .restricted:
            DispatchQueue.main.async {
                self.showPermissionAlert()
                self.isSavingToPhotos = false
            }
        @unknown default:
            DispatchQueue.main.async {
                self.showPermissionAlert()
                self.isSavingToPhotos = false
            }
        }
    }
    
    private func saveImageToPhotos() {
        photoSaver.saveImage(qrCodeImage) { success, error in
            DispatchQueue.main.async {
                self.isSavingToPhotos = false
                
                if success {
                    self.alertMessage = "二维码已保存到相册"
                } else {
                    self.alertMessage = "保存失败：\(error?.localizedDescription ?? "未知错误")"
                }
                self.showingAlert = true
            }
        }
    }
    
    private func showPermissionAlert() {
        alertMessage = "需要相册权限才能保存图片，请在设置中开启"
        showingAlert = true
    }
    
    // MARK: - 添加到图片
    private func addToPhotos() {
        // 先选择背景图片，然后跳转到图片合成界面
        showingBackgroundImagePicker = true
    }
}

// MARK: - 图片保存辅助类
class PhotoSaver: NSObject {
    func saveImage(_ image: UIImage, completion: @escaping (Bool, Error?) -> Void) {
        UIImageWriteToSavedPhotosAlbum(image, self, #selector(image(_:didFinishSavingWithError:contextInfo:)), nil)
        self.completion = completion
    }
    
    private var completion: ((Bool, Error?) -> Void)?
    
    @objc private func image(_ image: UIImage, didFinishSavingWithError error: Error?, contextInfo: UnsafeRawPointer) {
        completion?(error == nil, error)
    }
}

#Preview {
    let sampleImage = UIImage(systemName: "qrcode") ?? UIImage()
    let sampleStyleData = QRCodeStyleData(
        foregroundColor: "black",
        backgroundColor: "white",
        dotType: "square",
        eyeType: "square",
        logo: nil,
        hasCustomLogo: false,
        customLogoFileName: nil
    )
    
    return QRCodeSavedView(
        qrCodeImage: sampleImage,
        qrCodeContent: "https://example.com",
        qrCodeType: .url,
        styleData: sampleStyleData,
        historyItem: nil
    )
    .environmentObject(CoreDataManager())
}