import SwiftUI
import LabWiseKit

@Observable
final class AppState {
    var isAuthenticated: Bool = false
    var currentUser: AuthUser?

    static let shared = AppState()

    private let authClient = AuthClient()

    private init() {
        // Wire 401 handler
        APIClient.shared.onUnauthorized = { [weak self] in
            guard let self else { return }
            Task { @MainActor in
                self.signedOut()
            }
        }

        // If a session cookie exists, validate it with the server on launch
        let hasCookie = HTTPCookieStorage.shared.cookies?.contains {
            ($0.name == "__Secure-better-auth.session_token" || $0.name == "better-auth.session_token")
            && !$0.value.isEmpty
        } ?? false
        if hasCookie {
            // Optimistically show the authenticated UI, then validate
            isAuthenticated = true
            Task { @MainActor [weak self] in
                await self?.validateExistingSession()
            }
        }
    }

    @MainActor
    private func validateExistingSession() async {
        do {
            let user = try await authClient.fetchCurrentUser()
            currentUser = user
            isAuthenticated = true
        } catch {
            // Cookie was stale or invalid
            signedOut()
        }
    }

    @MainActor
    func signedIn(user: AuthUser) {
        currentUser = user
        isAuthenticated = true
    }

    @MainActor
    func signedOut() {
        currentUser = nil
        isAuthenticated = false
    }
}