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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 Microsoft.Extensions.DependencyInjection;
using Opc.Ua.Configuration;

#nullable enable

namespace Opc.Ua.Lds.Server.Hosting
{
    /// <summary>
    /// Options for an OPC UA Local Discovery Server (LDS / LDS-ME) hosted
    /// by the .NET Generic Host via
    /// <see cref="OpcUaLdsServerBuilderExtensions.AddLdsServer(IOpcUaBuilder, Action{LdsServerOptions})"/>.
    /// </summary>
    /// <remarks>
    /// Only the most common knobs are exposed directly. Use
    /// <see cref="ConfigureBuilder"/> for full control of the underlying
    /// <see cref="IApplicationConfigurationBuilder"/> chain (security policies,
    /// transport quotas, custom security stores, etc.).
    /// </remarks>
    public sealed class LdsServerOptions
    {
        /// <summary>
        /// Application name. Used as the default for the certificate subject
        /// common-name and the PKI root path when those are not set explicitly.
        /// </summary>
        public string ApplicationName { get; set; } = "LdsServer";

        /// <summary>
        /// Application URI (e.g. <c>urn:localhost:UA:LocalDiscoveryServer</c>).
        /// Required.
        /// </summary>
        public string ApplicationUri { get; set; } = string.Empty;

        /// <summary>
        /// Product URI (e.g. <c>uri:opcfoundation.org:LocalDiscoveryServer</c>).
        /// Required.
        /// </summary>
        public string ProductUri { get; set; } = string.Empty;

        /// <summary>
        /// Optional explicit certificate subject. When not set, defaults to
        /// <c>CN={ApplicationName}, O=OPC Foundation, DC=localhost</c>.
        /// </summary>
        public string SubjectName { get; set; } = string.Empty;

        /// <summary>
        /// Listen URLs. Per OPC 10000-12 the canonical LDS endpoint is
        /// <c>opc.tcp://{host}:4840</c>; tests typically use ephemeral ports.
        /// Mutated in place by <c>options.EndpointUrls.Add(...)</c>.
        /// </summary>
        public IList<string> EndpointUrls { get; } = [];

        /// <summary>
        /// Filesystem root used for the certificate stores. When empty, defaults
        /// to <c>%TEMP%/OPC Foundation/{ApplicationName}/pki</c>.
        /// </summary>
        public string PkiRoot { get; set; } = string.Empty;

        /// <summary>
        /// Whether unknown peer certificates are auto-accepted. Convenient for
        /// quickstart samples; do not enable in production.
        /// </summary>
        public bool AutoAcceptUntrustedCertificates { get; set; }

        /// <summary>
        /// When <c>true</c> (the default) and the platform supports it, the
        /// hosted LDS announces itself via mDNS (LDS-ME, OPC 10000-12 §6.4.6)
        /// using <see cref="MulticastDiscovery"/>. Disable on platforms
        /// without multicast support or in test environments.
        /// </summary>
        public bool EnableMulticast { get; set; } = true;

        /// <summary>
        /// Restrict the multicast announcer to the loopback NIC. Intended
        /// for in-process tests where the LDS-ME traffic must stay local.
        /// Ignored when <see cref="EnableMulticast"/> is <c>false</c>.
        /// </summary>
        public bool MulticastLoopbackOnly { get; set; }

        /// <summary>
        /// Extra server capabilities to advertise. Each entry is appended
        /// via <c>IApplicationConfigurationBuilderServerOptions.AddServerCapabilities</c>
        /// and surfaces in <see cref="ServerConfiguration.ServerCapabilities"/>.
        /// The hosted LDS always adds <c>LDS</c> (and <c>LDS-ME</c> when
        /// multicast is enabled) per OPC 10000-12 Annex D; entries here are
        /// additive. Mutated in place by
        /// <c>options.ServerCapabilities.Add(...)</c>.
        /// </summary>
        public IList<string> ServerCapabilities { get; } = [];

        /// <summary>
        /// Optional escape hatch invoked after the standard configuration steps
        /// (transport quotas, server policies, security configuration) but
        /// before <c>CreateAsync</c>. Use it to add bespoke security policies,
        /// override quotas, or add custom security stores.
        /// </summary>
        public Action<IApplicationConfigurationBuilderServerSelected>? ConfigureBuilder { get; set; }
    }
}