import Foundation

enum DefaultContainer {
    private static let credentials: any CredentialStore = FileCredentialStore(
        location: documentFileURL("credentials.json")
    )

    private static let logStore: any LogStore = FileLogStore(
        location: documentFileURL("log-center.json")
    )

    /// The phone's relay identity, shared by every relay transport.
    ///
    /// It is loaded once rather than per transport: the key pair must be the same one the node
    /// paired with, and a second load that regenerated it would silently invalidate every pairing.
    static let deviceIdentities = FileDeviceIdentityStore(
        location: documentFileURL("device-identity.json")
    )

    static func documentFileURL(_ name: String) -> URL {
        let directory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0]
        return directory.appendingPathComponent(name)
    }

    static func makeInstanceRepository() -> FileInstanceRepository {
        FileInstanceRepository(location: documentFileURL("instances.json"))
    }

    /// The transport pair every feature service uses: direct on the LAN, relay through the agent.
    ///
    /// The relay side reads the identity file per request rather than holding a copy: pairing can
    /// happen after a transport is built, and a held copy would sign with keys the node has never
    /// seen, which fails as an unreadable request with no useful cause.
    private static func makeTransport(
        client: any SimAdminClientProtocol,
        sessions: InstanceSessionStore
    ) -> NodeTransportRouter {
        let identities = deviceIdentities
        return NodeTransportRouter(
            direct: DirectTransport(client: client, sessions: sessions, credentials: credentials),
            relay: RelayTransport(identity: { try identities.loadOrCreate() })
        )
    }

    @MainActor
    static func makeFleetModel() -> FleetViewModel {
        purgeLegacyGrouping()
        let sessions = InstanceSessionStore()
        return FleetViewModel(
            repository: makeInstanceRepository(),
            probe: ConnectionProbe(transport: makeTransport(client: SimAdminClient(), sessions: sessions)),
            credentials: credentials,
            deviceService: DeviceService(
                transport: makeTransport(client: SimAdminClient(), sessions: sessions)
            )
        )
    }

    /// 0.2.2 起分组被标签取代，遗留的分组文件与偏好键一次性清掉，避免 Documents 里留死数据。
    private static func purgeLegacyGrouping() {
        try? FileManager.default.removeItem(at: documentFileURL("instance-groups.json"))
        UserDefaults.standard.removeObject(forKey: "fleet.groupMode")
    }

    @MainActor
    static func makeMessagesModel() -> MessagesViewModel {
        let sessions = InstanceSessionStore()
        return MessagesViewModel(
            repository: makeInstanceRepository(),
            service: MessageService(
                transport: makeTransport(client: SimAdminClient(), sessions: sessions)
            )
        )
    }

    @MainActor
    static func makeLogsModel(autoRefreshOnAppear: Bool = true) -> LogsViewModel {
        let store = logStore
        let sessions = InstanceSessionStore()
        return LogsViewModel(
            repository: makeInstanceRepository(),
            service: LogCenterService(
                transport: makeTransport(client: SimAdminClient(), sessions: sessions),
                store: store
            ),
            store: store,
            autoRefreshOnAppear: autoRefreshOnAppear
        )
    }

    @MainActor
    static func makeSettingsModel() -> SettingsViewModel {
        SettingsViewModel(store: logStore)
    }

    @MainActor
    static func makeDeviceModel(instance: Instance) -> DeviceViewModel {
        let sessions = InstanceSessionStore()
        return DeviceViewModel(
            instance: instance,
            service: DeviceService(
                transport: makeTransport(client: SimAdminClient(), sessions: sessions)
            ),
            probe: ConnectionProbe(
                transport: makeTransport(client: SimAdminClient(), sessions: sessions)
            )
        )
    }
}