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 * OPC Foundation MIT License 1.00
 *
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 * obtaining a copy of this software and associated documentation
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 * ======================================================================*/

using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using Opc.Ua.Identity;

namespace Opc.Ua.Server
{
    /// <summary>
    /// The interface that a server exposes to objects that it contains.
    /// </summary>
    public interface IServerInternal : IAuditEventServer, IDisposable
    {
        /// <summary>
        /// The endpoint addresses used by the server.
        /// </summary>
        /// <value>The endpoint addresses.</value>
        IEnumerable<Uri> EndpointAddresses { get; }

        /// <summary>
        /// The context to use when serializing/deserializing extension objects.
        /// </summary>
        /// <value>The message context.</value>
        IServiceMessageContext MessageContext { get; }

        /// <summary>
        /// The default system context for the server.
        /// </summary>
        /// <value>The default system context.</value>
        ServerSystemContext DefaultSystemContext { get; }

        /// <summary>
        /// The table of namespace uris known to the server.
        /// </summary>
        /// <value>The namespace URIs.</value>
        NamespaceTable NamespaceUris { get; }

        /// <summary>
        /// The table of remote server uris known to the server.
        /// </summary>
        /// <value>The server URIs.</value>
        StringTable ServerUris { get; }

        /// <summary>
        /// The factory used to create encodeable objects that the server understands.
        /// </summary>
        /// <value>The factory.</value>
        IEncodeableFactory Factory { get; }

        /// <summary>
        /// The datatypes, object types and variable types known to the server.
        /// </summary>
        /// <value>The type tree.</value>
        /// <remarks>
        /// The type tree table is a global object that all components of a server have access to.
        /// Node managers must populate this table with all types that they define.
        /// This object is thread safe.
        /// </remarks>
        TypeTable TypeTree { get; }

        /// <summary>
        /// The factory which helps creating main
        /// node managers used by the server.
        /// </summary>
        IMainNodeManagerFactory MainNodeManagerFactory { get; }

        /// <summary>
        /// The master node manager for the server.
        /// </summary>
        /// <value>The node manager.</value>
        IMasterNodeManager NodeManager { get; }

        /// <summary>
        /// The internal node manager for the servers.
        /// </summary>
        /// <value>The core node manager.</value>
        ICoreNodeManager CoreNodeManager { get; }

        /// <summary>
        /// Returns the node manager that managers the server diagnostics.
        /// </summary>
        /// <value>The diagnostics node manager.</value>
        IDiagnosticsNodeManager DiagnosticsNodeManager { get; }

        /// <summary>
        /// Returns the node manager that managers the server configuration.
        /// </summary>
        /// <value>The configuration node manager.</value>
        IConfigurationNodeManager ConfigurationNodeManager { get; }

        /// <summary>
        /// The manager for events that all components use to queue events that occur.
        /// </summary>
        /// <value>The event manager.</value>
        EventManager EventManager { get; }

        /// <summary>
        /// A manager for localized resources that components can use to localize text.
        /// </summary>
        /// <value>The resource manager.</value>
        ResourceManager ResourceManager { get; }

        /// <summary>
        /// A manager for outstanding requests that allows components to receive notifications if the timeout or are cancelled.
        /// </summary>
        /// <value>The request manager.</value>
        RequestManager RequestManager { get; }

        /// <summary>
        /// A manager for aggregate calculators supported by the server.
        /// </summary>
        /// <value>The aggregate manager.</value>
        AggregateManager AggregateManager { get; }

        /// <summary>
        /// A manager for modelling rules supported by the server.
        /// </summary>
        /// <value>The modelling rules manager.</value>
        ModellingRulesManager ModellingRulesManager { get; }

        /// <summary>
        /// The manager for active sessions.
        /// </summary>
        /// <value>The session manager.</value>
        ISessionManager SessionManager { get; }

        /// <summary>
        /// The manager for role identity / application / endpoint mapping rules
        /// per OPC UA Part 18 §6.4. <c>null</c> only on stripped-down server hosts
        /// that don't expose Server.ServerCapabilities.RoleSet. Integrators may
        /// override the default in-memory implementation by calling
        /// <see cref="SetRoleManager"/> before the address space is bound.
        /// </summary>
        IRoleManager RoleManager { get; }

        /// <summary>
        /// The registry that validates user identity tokens before falling back
        /// to the legacy <c>SessionManager.ImpersonateUser</c> event. Integrators
        /// may replace the default empty registry by calling
        /// <see cref="SetIdentityRegistry"/> before sessions are activated.
        /// </summary>
        IServerIdentityRegistry IdentityRegistry { get; }

        /// <summary>
        /// The manager for the OPC UA Part 18 §5 user-management model.
        /// <c>null</c> when the server doesn't expose
        /// <c>ServerConfiguration.UserManagement</c>. Integrators inject a
        /// concrete instance by calling <see cref="SetUserManagement"/>.
        /// </summary>
        UserManagement.IUserManagement? UserManagement { get; }

        /// <summary>
        /// The manager for active subscriptions.
        /// </summary>
        ISubscriptionManager SubscriptionManager { get; }

        /// <summary>
        /// The factory for (durable) monitored item queues
        /// </summary>
        IMonitoredItemQueueFactory MonitoredItemQueueFactory { get; }

        /// <summary>
        /// The store to persist and retrieve subscriptions
        /// </summary>
        ISubscriptionStore SubscriptionStore { get; }

        /// <summary>
        /// The server's telemetry context
        /// </summary>
        ITelemetryContext Telemetry { get; }

        /// <summary>
        /// Whether the server is currently running.
        /// </summary>
        /// <value>
        /// 	<c>true</c> if this instance is running; otherwise, <c>false</c>.
        /// </value>
        /// <remarks>
        /// This flag is set to false when the server shuts down. Threads running should check this flag whenever
        /// they return from a blocking operation. If it is false the thread should clean up and terminate.
        /// </remarks>
        bool IsRunning { get; }

        /// <summary>
        /// Returns the status object for the server.
        /// </summary>
        /// <value>The status.</value>
        [Obsolete("No longer thread safe. To read the value use CurrentState, to write use UpdateServerStatus.")]
        ServerStatusValue Status { get; }

        /// <summary>
        /// Gets or sets the current state of the server.
        /// </summary>
        /// <value>The state of the current.</value>
        ServerState CurrentState { get; set; }

        /// <summary>
        /// Returns the Server object node
        /// </summary>
        /// <value>The Server object node.</value>
        ServerObjectState ServerObject { get; }

        /// <summary>
        /// Used to synchronize access to the server diagnostics.
        /// </summary>
        /// <value>The diagnostics lock.</value>
        object DiagnosticsLock { get; }

        /// <summary>
        /// Used to synchronize write access to the server diagnostics.
        /// </summary>
        /// <value>The diagnostics lock.</value>
        object DiagnosticsWriteLock { get; }

        /// <summary>
        /// Returns the diagnostics structure for the server.
        /// </summary>
        /// <value>The server diagnostics.</value>
        ServerDiagnosticsSummaryDataType ServerDiagnostics { get; }

        /// <summary>
        /// Whether the server is collecting diagnostics.
        /// </summary>
        /// <value><c>true</c> if diagnostics is enabled; otherwise, <c>false</c>.</value>
        bool DiagnosticsEnabled { get; }

        /// <summary>
        /// Closes the specified session.
        /// </summary>
        /// <param name="context">The context.</param>
        /// <param name="sessionId">The session identifier.</param>
        /// <param name="deleteSubscriptions">if set to <c>true</c> subscriptions are to be deleted.</param>
        [Obsolete("Use CloseSessionAsync instead.")]
        void CloseSession(OperationContext context, NodeId sessionId, bool deleteSubscriptions);

        /// <summary>
        /// Closes the specified session.
        /// </summary>
        /// <param name="context">The context.</param>
        /// <param name="sessionId">The session identifier.</param>
        /// <param name="deleteSubscriptions">if set to <c>true</c> subscriptions are to be deleted.</param>
        /// <param name="cancellationToken">The cancellation token.</param>
        ValueTask CloseSessionAsync(
            OperationContext context,
            NodeId sessionId,
            bool deleteSubscriptions,
            CancellationToken cancellationToken = default);

        /// <summary>
        /// Deletes the specified subscription.
        /// </summary>
        /// <param name="subscriptionId">The subscription identifier.</param>
        /// <param name="cancellationToken">The cancellation token.</param>
        ValueTask DeleteSubscriptionAsync(uint subscriptionId, CancellationToken cancellationToken = default);

        /// <summary>
        /// Called by any component to report a global event.
        /// </summary>
        /// <param name="e">The event.</param>
        void ReportEvent(IFilterTarget e);

        /// <summary>
        /// Called by any component to report a global event.
        /// </summary>
        /// <param name="context">The context.</param>
        /// <param name="e">The event.</param>
        void ReportEvent(ISystemContext context, IFilterTarget e);

        /// <summary>
        /// Refreshes the conditions for the specified subscription.
        /// </summary>
        /// <param name="context">The context.</param>
        /// <param name="subscriptionId">The subscription identifier.</param>
        void ConditionRefresh(OperationContext context, uint subscriptionId);

        /// <summary>
        /// Refreshes the conditions for the specified subscription and monitored item.
        /// </summary>
        /// <param name="context">The context.</param>
        /// <param name="subscriptionId">The subscription identifier.</param>
        /// <param name="monitoredItemId">The monitored item identifier.</param>
        void ConditionRefresh2(OperationContext context, uint subscriptionId, uint monitoredItemId);

        /// <summary>
        /// Sets the EventManager, the ResourceManager, the RequestManager and the AggregateManager.
        /// </summary>
        /// <param name="eventManager">The event manager.</param>
        /// <param name="resourceManager">The resource manager.</param>
        /// <param name="requestManager">The request manager.</param>
        /// <param name="cancellationToken">The cancellation token.</param>
        ValueTask CreateServerObjectAsync(
            EventManager eventManager,
            ResourceManager resourceManager,
            RequestManager requestManager,
            CancellationToken cancellationToken = default);

        /// <summary>
        /// Stores the MasterNodeManager and the CoreNodeManager
        /// </summary>
        /// <param name="nodeManager">The node manager.</param>
        void SetNodeManager(IMasterNodeManager nodeManager);

        /// <summary>
        /// Stores the MainNodeManagerFactory
        /// </summary>
        /// <param name="mainNodeManagerFactory">The main node manager factory.</param>
        void SetMainNodeManagerFactory(IMainNodeManagerFactory mainNodeManagerFactory);

        /// <summary>
        /// Stores the SessionManager, the SubscriptionManager in the datastore.
        /// </summary>
        /// <param name="sessionManager">The session manager.</param>
        /// <param name="subscriptionManager">The subscription manager.</param>
        void SetSessionManager(
            ISessionManager sessionManager,
            ISubscriptionManager subscriptionManager);

        /// <summary>
        /// Stores the MonitoredItemQueueFactory in the datastore.
        /// </summary>
        /// <param name="monitoredItemQueueFactory">The MonitoredItemQueueFactory.</param>
        void SetMonitoredItemQueueFactory(IMonitoredItemQueueFactory monitoredItemQueueFactory);

        /// <summary>
        /// Stores the Subscriptionstore in the datastore.
        /// </summary>
        /// <param name="subscriptionStore">The subscriptionstore.</param>
        void SetSubscriptionStore(ISubscriptionStore subscriptionStore);

        /// <summary>
        /// Replaces the role manager with a custom <see cref="IRoleManager"/>
        /// implementation. Must be called before the diagnostics node manager
        /// binds the address space (typically before <c>StartServer</c>).
        /// Integrators use this to plug a persistent backing store, an LDAP
        /// directory, etc., in place of the default in-memory
        /// <see cref="Server.RoleManager"/>.
        /// </summary>
        /// <param name="roleManager">The role manager to use.</param>
        void SetRoleManager(IRoleManager roleManager);

        /// <summary>
        /// Replaces the identity registry with a custom
        /// <see cref="IServerIdentityRegistry"/> implementation. Must be
        /// called before sessions are activated so authenticators can run
        /// ahead of the legacy impersonation event.
        /// </summary>
        /// <param name="registry">The identity registry to use.</param>
        void SetIdentityRegistry(IServerIdentityRegistry registry);

        /// <summary>
        /// Replaces the user-management facade with a custom
        /// <see cref="UserManagement.IUserManagement"/>
        /// implementation. Must be called before the configuration node
        /// manager binds the address space (typically before <c>StartServer</c>).
        /// </summary>
        /// <param name="userManagement">The user-management facade.</param>
        void SetUserManagement(UserManagement.IUserManagement userManagement);

        /// <summary>
        /// Stores the AggregateManager in the datastore.
        /// </summary>
        /// <param name="aggregateManager">The AggregateManager.</param>
        void SetAggregateManager(AggregateManager aggregateManager);

        /// <summary>
        /// Stores the ModellingRulesManager in the datastore.
        /// </summary>
        /// <param name="modellingRulesManager">The ModellingRulesManager.</param>
        void SetModellingRulesManager(ModellingRulesManager modellingRulesManager);

        /// <summary>
        /// Updates the server status safely.
        /// </summary>
        /// <param name="action">Action to perform on the server status object.</param>
        void UpdateServerStatus(Action<ServerStatusValue> action);
    }
}