using System.Collections.Generic;
using ZB.MOM.WW.LmxOpcUa.Host.Configuration;
using ZB.MOM.WW.LmxOpcUa.Host.Domain;

namespace ZB.MOM.WW.LmxOpcUa.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 AppConfiguration _config = new AppConfiguration();
        private IMxProxy? _mxProxy;
        private IGalaxyRepository? _galaxyRepository;
        private IMxAccessClient? _mxAccessClient;
        private bool _mxProxySet;
        private bool _galaxyRepositorySet;
        private bool _mxAccessClientSet;

        /// <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>
        public OpcUaServiceBuilder DisableDashboard()
        {
            _config.Dashboard.Enabled = false;
            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>
        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);
        }

        /// <summary>
        /// Internal fake repository used by WithHierarchy for convenience.
        /// </summary>
        private class FakeBuilderGalaxyRepository : IGalaxyRepository
        {
            /// <summary>
            /// Occurs when the fake repository wants to simulate a Galaxy deploy change.
            /// </summary>
            public event System.Action? OnGalaxyChanged;

            /// <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>
            /// 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 System.Threading.Tasks.Task<List<GalaxyObjectInfo>> GetHierarchyAsync(System.Threading.CancellationToken ct = default)
                => System.Threading.Tasks.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 System.Threading.Tasks.Task<List<GalaxyAttributeInfo>> GetAttributesAsync(System.Threading.CancellationToken ct = default)
                => System.Threading.Tasks.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 System.Threading.Tasks.Task<System.DateTime?> GetLastDeployTimeAsync(System.Threading.CancellationToken ct = default)
                => System.Threading.Tasks.Task.FromResult<System.DateTime?>(System.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 System.Threading.Tasks.Task<bool> TestConnectionAsync(System.Threading.CancellationToken ct = default)
                => System.Threading.Tasks.Task.FromResult(true);
        }
    }
}