//
//  SceneDelegate.swift
//  suixinkan
//

import UIKit

class SceneDelegate: UIResponder, UIWindowSceneDelegate {

    var window: UIWindow?
    private var sessionExpiredDialog: SessionExpiredDialogViewController?

    func scene(
        _ scene: UIScene,
        willConnectTo session: UISceneSession,
        options connectionOptions: UIScene.ConnectionOptions
    ) {
        guard let windowScene = scene as? UIWindowScene else { return }

        AppNavigationBarAppearance.applyGlobalAppearance()

        let debugPreviewRoot = makeAccountDeletionDebugPreviewRootIfNeeded()
        if debugPreviewRoot == nil {
            enforceAccountDeletionStateBeforeLaunch()
        }

        let window = UIWindow(windowScene: windowScene)
        window.rootViewController = debugPreviewRoot ?? AppRouter.makeRootViewController()
        window.makeKeyAndVisible()
        self.window = window
        (UIApplication.shared.delegate as? AppDelegate)?.window = window

        PushNotificationManager.shared.attach(window: window)

        registerNotifications()

        if AppStore.shared.session.isLoggedIn {
            DispatchQueue.main.async {
                PushNotificationManager.shared.handleLoginCompleted()
            }
        }
        if let response = connectionOptions.notificationResponse {
            PushNotificationManager.shared.handleNotificationResponse(response)
        }
    }

    func sceneDidDisconnect(_ scene: UIScene) {
        NotificationCenter.default.removeObserver(self)
        if (UIApplication.shared.delegate as? AppDelegate)?.window === window {
            (UIApplication.shared.delegate as? AppDelegate)?.window = nil
        }
    }

    func scene(_ scene: UIScene, openURLContexts URLContexts: Set<UIOpenURLContext>) {
        guard let url = URLContexts.first?.url else { return }
        _ = WeChatManager.shared.handleOpenURL(url)
    }

    func scene(_ scene: UIScene, continue userActivity: NSUserActivity) {
        _ = WeChatManager.shared.handleContinueUserActivity(userActivity)
    }

    func sceneDidBecomeActive(_ scene: UIScene) {
        PushNotificationManager.shared.retryPendingRegistrationUpload()
    }

    private func registerNotifications() {
        NotificationCenter.default.addObserver(
            self,
            selector: #selector(handleSessionDidExpire),
            name: NotificationName.sessionDidExpire,
            object: nil
        )
        NotificationCenter.default.addObserver(
            self,
            selector: #selector(handleUserDidLogout),
            name: NotificationName.userDidLogout,
            object: nil
        )
        NotificationCenter.default.addObserver(
            self,
            selector: #selector(handleUserDidLogin),
            name: NotificationName.userDidLogin,
            object: nil
        )
        NotificationCenter.default.addObserver(
            self,
            selector: #selector(handleAccountDidSwitch),
            name: NotificationName.accountDidSwitch,
            object: nil
        )
    }

    /// 为设计核对提供仅 Debug 生效的注销页直达入口，不影响正式启动流程。
    private func makeAccountDeletionDebugPreviewRootIfNeeded() -> UIViewController? {
#if DEBUG
        guard ProcessInfo.processInfo.arguments.contains("--account-deletion-preview") else { return nil }
        let service = AccountDeletionMockService(responseDelayNanoseconds: 0)
        let viewModel = AccountDeletionViewModel(username: "18651857230", service: service)
        return UINavigationController(rootViewController: AccountDeletionViewController(viewModel: viewModel))
#else
        return nil
#endif
    }

    /// App 冷启动时若账号已进入注销冷静期，则清除旧登录态并返回登录页。
    private func enforceAccountDeletionStateBeforeLaunch() {
        guard AppStore.shared.session.isLoggedIn,
              let username = AccountDeletionIdentity.currentUsername() else { return }
        switch AccountDeletionMockService.shared.loginState(for: username) {
        case .pending, .completed:
            AppStore.shared.logout()
        case .none:
            break
        }
    }

    @objc private func handleSessionDidExpire() {
        guard AppStore.shared.session.isLoggedIn else { return }
        guard sessionExpiredDialog == nil else { return }

        GlobalLoadingManager.shared.hideAll()
        let dialog = SessionExpiredDialogViewController { [weak self] in
            self?.transitionToLogin()
        }
        sessionExpiredDialog = dialog

        guard let presenter = topViewController(from: window?.rootViewController) else {
            sessionExpiredDialog = nil
            return
        }
        presenter.present(dialog, animated: true)
    }

    private func transitionToLogin() {
        sessionExpiredDialog = nil
        PushNotificationManager.shared.handleLogout()
        AppStore.shared.logout()
        AppRouter.setRoot(.login, on: window)
    }

    @objc private func handleUserDidLogout() {
        transitionToLogin()
    }

    @objc private func handleUserDidLogin() {
        sessionExpiredDialog?.dismiss(animated: false)
        sessionExpiredDialog = nil
        AppRouter.setRoot(.mainTab, on: window)
        DispatchQueue.main.async {
            PushNotificationManager.shared.handleLoginCompleted()
            PushNotificationManager.shared.routePendingNotificationIfPossible()
        }
    }

    @objc private func handleAccountDidSwitch() {
        PushNotificationManager.shared.handleAccountSwitched()
    }

    private func topViewController(from viewController: UIViewController?) -> UIViewController? {
        guard let viewController else { return nil }
        if let presented = viewController.presentedViewController {
            return topViewController(from: presented)
        }
        if let navigationController = viewController as? UINavigationController {
            return topViewController(from: navigationController.visibleViewController)
        }
        if let tabBarController = viewController as? UITabBarController {
            return topViewController(from: tabBarController.selectedViewController)
        }
        return viewController
    }
}