import Expo
import React
import ReactAppDependencyProvider
import BackgroundTasks

@UIApplicationMain
public class AppDelegate: ExpoAppDelegate {
  var window: UIWindow?

  var reactNativeDelegate: ExpoReactNativeFactoryDelegate?
  var reactNativeFactory: RCTReactNativeFactory?

  public override func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]? = nil
  ) -> Bool {
    // 注意：必须在 super.application() 之前注册后台任务
    // 这是 BGTaskScheduler 的硬性要求，否则任务永远不会被触发
    if #available(iOS 13.0, *) {
      registerBackgroundTasks()
    }
    
    let delegate = ReactNativeDelegate()
    let factory = ExpoReactNativeFactory(delegate: delegate)
    delegate.dependencyProvider = RCTAppDependencyProvider()

    reactNativeDelegate = delegate
    reactNativeFactory = factory
    bindReactNativeFactory(factory)

#if os(iOS) || os(tvOS)
    window = UIWindow(frame: UIScreen.main.bounds)
    factory.startReactNative(
      withModuleName: "main",
      in: window,
      launchOptions: launchOptions)
#endif

    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
  }
  
  // MARK: - Application Lifecycle
  
  public override func applicationDidEnterBackground(_ application: UIApplication) {
    super.applicationDidEnterBackground(application)
    
    // 后台任务调度现在由 BackgroundTaskBridge 统一管理
    // 这里只需要确保应用有足够的时间完成后台任务
    if #available(iOS 13.0, *) {
      NSLog("[AppDelegate] 应用进入后台，后台任务由 BackgroundTaskBridge 管理")
    }
  }
  
  // MARK: - Background Task Registration
  
  @available(iOS 13.0, *)
  private func registerBackgroundTasks() {
    let identifier = "com.anonymous.digitalpilates.task"
    
    // 注册后台任务处理器
    // 必须在应用启动完成前注册，否则会崩溃
    BGTaskScheduler.shared.register(
      forTaskWithIdentifier: identifier,
      using: nil
    ) { [weak self] task in
      NSLog("[AppDelegate] ✅ 后台任务被系统触发: \(identifier)")
      // 尝试通知 BackgroundTaskBridge 处理任务
      // 如果 bridge 不可用，标记任务完成
      self?.handleBackgroundTask(task, identifier: identifier)
    }
    
    NSLog("[AppDelegate] 后台任务已在应用启动时注册: \(identifier)")
    
    // 额外注册 processing 类型的任务（如果需要）
    let processingIdentifier = "com.anonymous.digitalpilates.processing"
    BGTaskScheduler.shared.register(
      forTaskWithIdentifier: processingIdentifier,
      using: nil
    ) { [weak self] task in
      NSLog("[AppDelegate] ✅ Processing 后台任务被系统触发: \(processingIdentifier)")
      self?.handleBackgroundTask(task, identifier: processingIdentifier)
    }
    
    NSLog("[AppDelegate] Processing 后台任务已注册: \(processingIdentifier)")
  }
  
  @available(iOS 13.0, *)
  private func handleBackgroundTask(_ task: BGTask, identifier: String) {
    NSLog("[AppDelegate] ====== 后台任务被触发 ======")
    NSLog("[AppDelegate] 任务标识符: \(identifier)")
    NSLog("[AppDelegate] 任务类型: \(type(of: task))")
    NSLog("[AppDelegate] 触发时间: \(Date().description)")
    
    // 记录任务开始
    let defaults = UserDefaults.standard
    defaults.set(Date().timeIntervalSince1970, forKey: "last_background_task_trigger")
    NSLog("[AppDelegate] 已记录任务触发时间到UserDefaults")
    
    // 设置任务过期处理器（iOS 给的执行时间有限，通常30秒）
    task.expirationHandler = { [weak self] in
      NSLog("[AppDelegate] ⚠️ 后台任务即将过期，强制完成")
      task.setTaskCompleted(success: false)
      
      // 确保重新调度下一次任务
      if let strongSelf = self {
        strongSelf.scheduleNextBackgroundTask(identifier: identifier)
      }
    }
    
    // 尝试获取 BackgroundTaskBridge 实例来处理任务
    // 如果 React Native bridge 还未初始化，我们仍然可以执行一些基本的后台工作
    guard let bridge = reactNativeFactory?.bridge,
          bridge.isValid else {
      NSLog("[AppDelegate] React Native bridge 未就绪")
      NSLog("[AppDelegate] 执行基本的后台任务并调度下一次")
      
      // 即使 JS 层不可用，也执行基本的后台维护
      self.executeBasicBackgroundMaintenance(task: task, identifier: identifier)
      return
    }
    
    NSLog("[AppDelegate] React Native bridge 已就绪，尝试获取 BackgroundTaskBridge 模块")
    
    // 通过 bridge 查找 BackgroundTaskBridge 模块
    DispatchQueue.main.async {
      if let module = bridge.module(for: BackgroundTaskBridge.self) as? BackgroundTaskBridge {
        NSLog("[AppDelegate] ✅ 找到 BackgroundTaskBridge 模块，发送任务通知")
        // 通知 BackgroundTaskBridge 处理任务
        NotificationCenter.default.post(
          name: NSNotification.Name("BackgroundTaskBridge.handleTask"),
          object: nil,
          userInfo: ["task": task, "identifier": identifier]
        )
      } else {
        NSLog("[AppDelegate] ❌ BackgroundTaskBridge 模块未找到")
        NSLog("[AppDelegate] 执行基本的后台任务并调度下一次")
        self.executeBasicBackgroundMaintenance(task: task, identifier: identifier)
      }
    }
  }
  
  @available(iOS 13.0, *)
  private func executeBasicBackgroundMaintenance(task: BGTask, identifier: String) {
    NSLog("[AppDelegate] ===== 执行基本后台维护任务 =====")
    NSLog("[AppDelegate] 标识符: \(identifier)")
    NSLog("[AppDelegate] 开始时间: \(Date().description)")
    
    // 在后台线程执行基本维护
    DispatchQueue.global(qos: .background).async {
      // 执行一些基本的后台工作
      // 例如：清理缓存、检查应用状态等
      
      // 模拟一些工作
      Thread.sleep(forTimeInterval: 2.0)
      
      NSLog("[AppDelegate] 基本后台维护完成")
      
      // 标记任务完成
      task.setTaskCompleted(success: true)
      
      // 调度下一次后台任务
      self.scheduleNextBackgroundTask(identifier: identifier)
    }
  }
  
  @available(iOS 13.0, *)
  private func scheduleNextBackgroundTask(identifier: String) {
    NSLog("[AppDelegate] ===== 调度下一次后台任务 =====")
    NSLog("[AppDelegate] 标识符: \(identifier)")
    
    let request: BGTaskRequest
    if identifier.contains("processing") {
      request = BGProcessingTaskRequest(identifier: identifier)
      if let processingRequest = request as? BGProcessingTaskRequest {
        processingRequest.earliestBeginDate = Date(timeIntervalSinceNow: 15 * 60)
        processingRequest.requiresNetworkConnectivity = false
        processingRequest.requiresExternalPower = false
      }
    } else {
      request = BGAppRefreshTaskRequest(identifier: identifier)
      if let appRefreshRequest = request as? BGAppRefreshTaskRequest {
        appRefreshRequest.earliestBeginDate = Date(timeIntervalSinceNow: 15 * 60)
      }
    }
    
    let formatter = DateFormatter()
    formatter.dateFormat = "HH:mm:ss"
    let scheduledTime = formatter.string(from: Date(timeIntervalSinceNow: 15 * 60))
    NSLog("[AppDelegate] 计划执行时间: \(scheduledTime)")
    
    do {
      try BGTaskScheduler.shared.submit(request)
      NSLog("[AppDelegate] ✅ 成功调度下一次后台任务，15分钟后")
    } catch {
      NSLog("[AppDelegate] ❌ 调度下一次后台任务失败: \(error.localizedDescription)")
    }
  }

  // Linking API
  public override func application(
    _ app: UIApplication,
    open url: URL,
    options: [UIApplication.OpenURLOptionsKey: Any] = [:]
  ) -> Bool {
    return super.application(app, open: url, options: options) || RCTLinkingManager.application(app, open: url, options: options)
  }

  // Universal Links
  public override func application(
    _ application: UIApplication,
    continue userActivity: NSUserActivity,
    restorationHandler: @escaping ([UIUserActivityRestoring]?) -> Void
  ) -> Bool {
    let result = RCTLinkingManager.application(application, continue: userActivity, restorationHandler: restorationHandler)
    return super.application(application, continue: userActivity, restorationHandler: restorationHandler) || result
  }
}

class ReactNativeDelegate: ExpoReactNativeFactoryDelegate {
  // Extension point for config-plugins

  override func sourceURL(for bridge: RCTBridge) -> URL? {
    // needed to return the correct URL for expo-dev-client.
    bridge.bundleURL ?? bundleURL()
  }

  override func bundleURL() -> URL? {
#if DEBUG
    return RCTBundleURLProvider.sharedSettings().jsBundleURL(forBundleRoot: ".expo/.virtual-metro-entry")
#else
    return Bundle.main.url(forResource: "main", withExtension: "jsbundle")
#endif
  }
}