import SwiftUI

enum AppRoute: Hashable {
    case landing, login, register, pinLock, pinSetup, home
    case profile, settings, security, wallet, billing, support
}

struct AppRouter: View {
    @EnvironmentObject private var session: SessionStore
    @State private var path = NavigationPath()
    @State private var booted = false
    @State private var initialRoute: AppRoute = .landing

    var body: some View {
        NavigationStack(path: $path) {
            Group {
                if !booted {
                    SplashView(onFinish: handleSplashFinish)
                } else {
                    rootView
                }
            }
            .navigationDestination(for: AppRoute.self) { route in
                destination(for: route)
            }
        }
    }

    @ViewBuilder
    private var rootView: some View {
        switch initialRoute {
        case .pinLock: PinLockView(onUnlocked: { goHome() })
        case .home: HomeView(
            onNavigate: { path.append($0) },
            onLoggedOut: { resetToLanding() }
        )
        default: LandingView(
            onSignIn: { path.append(AppRoute.login) },
            onCreateAccount: { path.append(AppRoute.register) }
        )
        }
    }

    @ViewBuilder
    private func destination(for route: AppRoute) -> some View {
        switch route {
        case .landing:
            LandingView(
                onSignIn: { path.append(AppRoute.login) },
                onCreateAccount: { path.append(AppRoute.register) }
            )
        case .login:
            LoginView(
                onLoggedIn: { goHome() },
                onCreateAccount: {
                    path.removeLast(path.count)
                    path.append(AppRoute.register)
                },
                onBack: { path.removeLast() }
            )
        case .register:
            RegisterView(
                onRegistered: { goHome() },
                onSignIn: {
                    path.removeLast(path.count)
                    path.append(AppRoute.login)
                },
                onBack: { path.removeLast() }
            )
        case .pinLock:
            PinLockView(onUnlocked: { goHome() })
        case .pinSetup:
            PinSetupView(onPinSet: { goHome() })
        case .home:
            HomeView(onNavigate: { path.append($0) }, onLoggedOut: { resetToLanding() })
        case .profile:
            ProfileView(onBack: { path.removeLast() })
        case .settings:
            SettingsView(onBack: { path.removeLast() })
        case .security:
            SecurityView(onBack: { path.removeLast() })
        case .wallet:
            WalletView(onBack: { path.removeLast() })
        case .billing:
            BillingView(onBack: { path.removeLast() })
        case .support:
            SupportView(onBack: { path.removeLast() })
        }
    }

    private func handleSplashFinish() {
        booted = true
        if session.isLoggedIn {
            initialRoute = PinStore.shared.hasPin() ? .pinLock : .home
        } else {
            initialRoute = .landing
        }
    }

    private func goHome() {
        path = NavigationPath()
        initialRoute = .home
        booted = true
    }

    private func resetToLanding() {
        path = NavigationPath()
        initialRoute = .landing
        booted = true
    }
}