using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using ZB.MOM.WW.OtOpcUa.Host.Configuration;
using ZB.MOM.WW.OtOpcUa.Host.Domain;

namespace ZB.MOM.WW.OtOpcUa.Host
{
    /// <summary>
    ///     Fluent builder for constructing OpcUaService with dependency overrides.
    ///     Used by integration tests to substitute fakes for COM/DB components.
    /// </summary>
    internal class OpcUaServiceBuilder
    {
        private IUserAuthenticationProvider? _authProvider;
        private bool _authProviderSet;
        private AppConfiguration _config = new();
        private IGalaxyRepository? _galaxyRepository;
        private bool _galaxyRepositorySet;
        private IMxAccessClient? _mxAccessClient;
        private bool _mxAccessClientSet;
        private IMxProxy? _mxProxy;
        private bool _mxProxySet;

        /// <summary>
        ///     Replaces the default service configuration used by the test host.
        /// </summary>
        /// <param name="config">The full configuration snapshot to inject into the service under test.</param>
        /// <returns>The current builder so additional overrides can be chained.</returns>
        public OpcUaServiceBuilder WithConfig(AppConfiguration config)
        {
            _config = config;
            return this;
        }

        /// <summary>
        ///     Sets the OPC UA port used by the test host so multiple integration runs can coexist.
        /// </summary>
        /// <param name="port">The TCP port to expose for the test server.</param>
        /// <returns>The current builder so additional overrides can be chained.</returns>
        public OpcUaServiceBuilder WithOpcUaPort(int port)
        {
            _config.OpcUa.Port = port;
            return this;
        }

        /// <summary>
        ///     Sets the Galaxy name represented by the test address space.
        /// </summary>
        /// <param name="name">The Galaxy name to expose through OPC UA and diagnostics.</param>
        /// <returns>The current builder so additional overrides can be chained.</returns>
        public OpcUaServiceBuilder WithGalaxyName(string name)
        {
            _config.OpcUa.GalaxyName = name;
            return this;
        }

        /// <summary>
        ///     Injects an MXAccess proxy substitute for tests that exercise the proxy-driven runtime path.
        /// </summary>
        /// <param name="proxy">The proxy fake or stub to supply to the service.</param>
        /// <returns>The current builder so additional overrides can be chained.</returns>
        public OpcUaServiceBuilder WithMxProxy(IMxProxy? proxy)
        {
            _mxProxy = proxy;
            _mxProxySet = true;
            return this;
        }

        /// <summary>
        ///     Injects a repository substitute for tests that control Galaxy hierarchy and deploy metadata.
        /// </summary>
        /// <param name="repository">The repository fake or stub to supply to the service.</param>
        /// <returns>The current builder so additional overrides can be chained.</returns>
        public OpcUaServiceBuilder WithGalaxyRepository(IGalaxyRepository? repository)
        {
            _galaxyRepository = repository;
            _galaxyRepositorySet = true;
            return this;
        }

        /// <summary>
        ///     Override the MxAccessClient directly, skipping STA thread and COM interop entirely.
        ///     When set, the service will use this client instead of creating one from IMxProxy.
        /// </summary>
        /// <param name="client">The direct MXAccess client substitute to inject into the service.</param>
        /// <returns>The current builder so additional overrides can be chained.</returns>
        public OpcUaServiceBuilder WithMxAccessClient(IMxAccessClient? client)
        {
            _mxAccessClient = client;
            _mxAccessClientSet = true;
            return this;
        }

        /// <summary>
        ///     Seeds a convenience fake repository with Galaxy hierarchy and attribute rows for address-space tests.
        /// </summary>
        /// <param name="hierarchy">The object hierarchy to expose through the test OPC UA namespace.</param>
        /// <param name="attributes">The attribute rows to attach to the hierarchy.</param>
        /// <returns>The current builder so additional overrides can be chained.</returns>
        public OpcUaServiceBuilder WithHierarchy(List<GalaxyObjectInfo> hierarchy, List<GalaxyAttributeInfo> attributes)
        {
            if (!_galaxyRepositorySet)
            {
                var fake = new FakeBuilderGalaxyRepository();
                _galaxyRepository = fake;
                _galaxyRepositorySet = true;
            }

            if (_galaxyRepository is FakeBuilderGalaxyRepository fakeRepo)
            {
                fakeRepo.Hierarchy = hierarchy;
                fakeRepo.Attributes = attributes;
            }

            return this;
        }

        /// <summary>
        ///     Disables the embedded dashboard so tests can focus on the runtime bridge without binding the HTTP listener.
        /// </summary>
        /// <returns>The current builder so additional overrides can be chained.</returns>
        /// <summary>
        ///     Injects a custom authentication provider for tests that need deterministic role resolution.
        /// </summary>
        public OpcUaServiceBuilder WithAuthProvider(IUserAuthenticationProvider? provider)
        {
            _authProvider = provider;
            _authProviderSet = true;
            return this;
        }

        /// <summary>
        ///     Sets the authentication configuration for the test host.
        /// </summary>
        public OpcUaServiceBuilder WithAuthentication(AuthenticationConfiguration authConfig)
        {
            _config.Authentication = authConfig;
            return this;
        }

        public OpcUaServiceBuilder DisableDashboard()
        {
            _config.Dashboard.Enabled = false;
            return this;
        }

        /// <summary>
        ///     Sets the redundancy configuration for the test host.
        /// </summary>
        /// <param name="redundancy">The redundancy configuration to inject.</param>
        /// <returns>The current builder so additional overrides can be chained.</returns>
        public OpcUaServiceBuilder WithRedundancy(RedundancyConfiguration redundancy)
        {
            _config.Redundancy = redundancy;
            return this;
        }

        /// <summary>
        ///     Sets the application URI for the test host, distinct from the namespace URI.
        /// </summary>
        /// <param name="applicationUri">The unique application URI for this server instance.</param>
        /// <returns>The current builder so additional overrides can be chained.</returns>
        public OpcUaServiceBuilder WithApplicationUri(string applicationUri)
        {
            _config.OpcUa.ApplicationUri = applicationUri;
            return this;
        }

        /// <summary>
        ///     Sets the security profile configuration for the test host.
        /// </summary>
        /// <param name="security">The security profile configuration to inject.</param>
        /// <returns>The current builder so additional overrides can be chained.</returns>
        /// <summary>
        ///     Enables alarm condition tracking on the test host so integration tests can exercise the alarm-creation path.
        /// </summary>
        /// <param name="enabled">Whether alarm tracking should be enabled.</param>
        /// <returns>The current builder so additional overrides can be chained.</returns>
        public OpcUaServiceBuilder WithAlarmTracking(bool enabled)
        {
            _config.OpcUa.AlarmTrackingEnabled = enabled;
            return this;
        }

        /// <summary>
        ///     Configures the template-based alarm object filter for integration tests.
        /// </summary>
        /// <param name="filters">Zero or more wildcard patterns. Empty → filter disabled.</param>
        /// <returns>The current builder so additional overrides can be chained.</returns>
        public OpcUaServiceBuilder WithAlarmFilter(params string[] filters)
        {
            _config.OpcUa.AlarmFilter = new AlarmFilterConfiguration
            {
                ObjectFilters = filters.ToList()
            };
            return this;
        }

        public OpcUaServiceBuilder WithSecurity(SecurityProfileConfiguration security)
        {
            _config.Security = security;
            return this;
        }

        /// <summary>
        ///     Effectively disables Galaxy change detection by pushing the polling interval beyond realistic test durations.
        /// </summary>
        /// <returns>The current builder so additional overrides can be chained.</returns>
        public OpcUaServiceBuilder DisableChangeDetection()
        {
            _config.GalaxyRepository.ChangeDetectionIntervalSeconds = int.MaxValue;
            return this;
        }

        /// <summary>
        ///     Creates an <see cref="OpcUaService" /> using the accumulated test doubles and configuration overrides.
        /// </summary>
        /// <returns>A service instance ready for integration-style testing.</returns>
        public OpcUaService Build()
        {
            return new OpcUaService(
                _config,
                _mxProxySet ? _mxProxy : null,
                _galaxyRepositorySet ? _galaxyRepository : null,
                _mxAccessClientSet ? _mxAccessClient : null,
                _mxAccessClientSet,
                _authProviderSet ? _authProvider : null,
                _authProviderSet);
        }

        /// <summary>
        ///     Internal fake repository used by WithHierarchy for convenience.
        /// </summary>
        private class FakeBuilderGalaxyRepository : IGalaxyRepository
        {
            /// <summary>
            ///     Gets or sets the hierarchy rows that the fake repository returns to the service.
            /// </summary>
            public List<GalaxyObjectInfo> Hierarchy { get; set; } = new();

            /// <summary>
            ///     Gets or sets the attribute rows that the fake repository returns to the service.
            /// </summary>
            public List<GalaxyAttributeInfo> Attributes { get; set; } = new();

            /// <summary>
            ///     Occurs when the fake repository wants to simulate a Galaxy deploy change.
            /// </summary>
            public event Action? OnGalaxyChanged;

            /// <summary>
            ///     Returns the seeded hierarchy rows for address-space construction.
            /// </summary>
            /// <param name="ct">A cancellation token that is ignored by the in-memory fake.</param>
            /// <returns>The configured hierarchy rows.</returns>
            public Task<List<GalaxyObjectInfo>> GetHierarchyAsync(CancellationToken ct = default)
            {
                return Task.FromResult(Hierarchy);
            }

            /// <summary>
            ///     Returns the seeded attribute rows for address-space construction.
            /// </summary>
            /// <param name="ct">A cancellation token that is ignored by the in-memory fake.</param>
            /// <returns>The configured attribute rows.</returns>
            public Task<List<GalaxyAttributeInfo>> GetAttributesAsync(CancellationToken ct = default)
            {
                return Task.FromResult(Attributes);
            }

            /// <summary>
            ///     Returns the current UTC time so change-detection tests have a deploy timestamp to compare against.
            /// </summary>
            /// <param name="ct">A cancellation token that is ignored by the in-memory fake.</param>
            /// <returns>The current UTC time.</returns>
            public Task<DateTime?> GetLastDeployTimeAsync(CancellationToken ct = default)
            {
                return Task.FromResult<DateTime?>(DateTime.UtcNow);
            }

            /// <summary>
            ///     Reports a healthy repository connection for builder-based test setups.
            /// </summary>
            /// <param name="ct">A cancellation token that is ignored by the in-memory fake.</param>
            /// <returns>A completed task returning <see langword="true" />.</returns>
            public Task<bool> TestConnectionAsync(CancellationToken ct = default)
            {
                return Task.FromResult(true);
            }
        }
    }
}