import SwiftUI
import UserNotifications
import Photos

/// 权限管理视图，用于管理应用的各种权限设置
struct PermissionManagementView: View {
    // MARK: - 状态变量
    @State private var photoLibraryStatus: PHAuthorizationStatus = .notDetermined  // 相册权限状态
    @State private var notificationStatus: UNAuthorizationStatus = .notDetermined  // 通知权限状态
    
    var body: some View {
        ZStack {
            // 设置整体背景色
            Color.themeTextWhiteSecondary
                .edgesIgnoringSafeArea(.all)
            
            VStack(spacing: 0) {
                // 自定义导航栏
                SimpleNaviHeader(title: "Permission Management") {
                    Router.shared.pop()  // 返回上一页
                }
                .padding(.top, UIApplication.shared.windows.first?.safeAreaInsets.top ?? 0)
                
                // 权限设置卡片
                VStack(spacing: 0) {
                    // 1. 相册权限
                    PermissionRow(
                        title: "Gallery Permissions",
                        isEnabled: photoLibraryStatus == .authorized
                    ) {
                        requestPhotoLibraryPermission()  // 请求相册权限
                    }
                    
                    // 2. 通知权限
                    PermissionRow(
                        title: "Notification Permissions",
                        isEnabled: notificationStatus == .authorized
                    ) {
                        requestNotificationPermission()  // 请求通知权限
                    }
                }
                .background(Color.white)
                .cornerRadius(16)
                .padding()
                
                Spacer()  // 将内容推到顶部
            }
        }
        .navigationBarHidden(true)  // 隐藏系统导航栏
        .edgesIgnoringSafeArea(.all)
        .onAppear {
            // 视图出现时检查权限状态
            checkPhotoLibraryPermission()
            checkNotificationPermission()
        }
    }
    
    // MARK: - 相册权限相关方法
    
    /// 检查相册权限状态
    private func checkPhotoLibraryPermission() {
        photoLibraryStatus = PHPhotoLibrary.authorizationStatus()
    }
    
    /// 请求相册权限
    private func requestPhotoLibraryPermission() {
        // 如果未授权，则请求权限
        if photoLibraryStatus == .notDetermined {
            PHPhotoLibrary.requestAuthorization { status in
                DispatchQueue.main.async {
                    self.photoLibraryStatus = status
                    // 如果用户拒绝，则打开应用设置
                    if status != .authorized {
                        self.openAppSettings()
                    }
                }
            }
        } else {
            // 如果已决定过权限，则直接打开设置
            openAppSettings()
        }
    }
    
    // MARK: - 通知权限相关方法
    
    /// 检查通知权限状态
    private func checkNotificationPermission() {
        UNUserNotificationCenter.current().getNotificationSettings { settings in
            DispatchQueue.main.async {
                self.notificationStatus = settings.authorizationStatus
            }
        }
    }
    
    /// 请求通知权限
    private func requestNotificationPermission() {
        UNUserNotificationCenter.current().getNotificationSettings { settings in
            // 如果从未请求过权限
            if settings.authorizationStatus == .notDetermined {
                // 请求通知权限
                UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .badge, .sound]) { granted, _ in
                    DispatchQueue.main.async {
                        self.notificationStatus = granted ? .authorized : .denied
                        // 如果用户拒绝，则打开应用设置
                        if !granted {
                            self.openAppSettings()
                        }
                    }
                }
            } else {
                // 如果已经请求过权限，则直接打开设置
                DispatchQueue.main.async {
                    self.openAppSettings()
                }
            }
        }
    }
    
    // MARK: - 辅助方法
    
    /// 打开应用设置页面
    private func openAppSettings() {
        if let url = URL(string: UIApplication.openSettingsURLString) {
            UIApplication.shared.open(url)
        }
    }
}

/// 权限设置行视图
struct PermissionRow: View {
    let title: String          // 权限名称
    let isEnabled: Bool        // 是否已授权
    let action: () -> Void     // 点击事件
    
    var body: some View {
        Button(action: action) {
            HStack {
                // 权限名称
                Text(title)
                    .foregroundColor(.primary)
                    .font(.system(size: 16))
                
                Spacer()
                
                // 权限开关
                Toggle("", isOn: .constant(isEnabled))
                    .labelsHidden()
                    .tint(Color.themePrimary)
                    .disabled(true)
                    .onAppear {
                        // 使用主题色并确保完全不透明
                        let themeColor = UIColor(Color.themePrimary)
                        UISwitch.appearance(whenContainedInInstancesOf: [UIView.self]).onTintColor = themeColor
                        UISwitch.appearance(whenContainedInInstancesOf: [UIView.self]).thumbTintColor = .white
                        // 确保使用不透明的背景
                        UISwitch.appearance(whenContainedInInstancesOf: [UIView.self]).backgroundColor = UIColor.clear
                    }
            }
            .padding()
        }
        .buttonStyle(PlainButtonStyle())
        // 添加底部边框
        .overlay(
            Rectangle()
                .frame(height: 1)
                .foregroundColor(Color(.systemGray6)),
            alignment: .bottom
        )
    }
}

// 预览
#Preview {
    PermissionManagementView()
}