shaguabijia-app-ios/App/Auth/SessionStore.swift

import SwiftUI

/// 登录态真相源(UI 订阅)。token 实际存 Keychain,这里持内存镜像 + user 资料。
@MainActor
@Observable
final class SessionStore {
    var user: UserDTO?
    private(set) var isLoggedIn: Bool
    @ObservationIgnored private var authExpireObserver: NSObjectProtocol?

    init() {
        // 启动即判断:Keychain 有 access token 视为已登录(资料由 refreshProfile 拉)
        isLoggedIn = KeychainStore.get(.accessToken) != nil
        authExpireObserver = NotificationCenter.default.addObserver(
            forName: .authDidExpire, object: nil, queue: .main
        ) { [weak self] _ in
            MainActor.assumeIsolated { self?.clearLocal() }
        }
    }

    deinit {
        if let authExpireObserver {
            NotificationCenter.default.removeObserver(authExpireObserver)
        }
    }

    /// 登录成功:存 token + user。
    func loginSucceeded(_ resp: TokenWithUserDTO) async {
        await AuthTokens.shared.setTokens(access: resp.accessToken, refresh: resp.refreshToken)
        user = resp.user
        isLoggedIn = true
    }

    /// 资料更新后(改昵称/头像)同步内存镜像。
    func updateUser(_ user: UserDTO) {
        self.user = user
    }

    /// 拉最新资料(进入「我的」时刷新)。
    func refreshProfile() async {
        guard isLoggedIn else { return }
        if let u = try? await AuthService().me() { user = u }
    }

    /// 主动退出登录。
    func logout() async {
        _ = try? await AuthService().logout()   // 占位接口,失败也无所谓
        await AuthTokens.shared.clear()
        clearLocal()
    }

    private func clearLocal() {
        user = nil
        isLoggedIn = false
    }
}