using Microsoft.Extensions.Configuration;
using Shouldly;
using Xunit;
using ZB.MOM.WW.LmxOpcUa.Host.Configuration;

namespace ZB.MOM.WW.LmxOpcUa.Tests.Configuration
{
    /// <summary>
    /// Verifies that application configuration binds correctly from appsettings and that validation catches invalid bridge settings.
    /// </summary>
    public class ConfigurationLoadingTests
    {
        /// <summary>
        /// Loads the application configuration from the repository appsettings file for binding tests.
        /// </summary>
        /// <returns>The bound application configuration snapshot.</returns>
        private static AppConfiguration LoadFromJson()
        {
            var configuration = new ConfigurationBuilder()
                .AddJsonFile("appsettings.json", optional: false)
                .Build();

            var config = new AppConfiguration();
            configuration.GetSection("OpcUa").Bind(config.OpcUa);
            configuration.GetSection("MxAccess").Bind(config.MxAccess);
            configuration.GetSection("GalaxyRepository").Bind(config.GalaxyRepository);
            configuration.GetSection("Dashboard").Bind(config.Dashboard);
            return config;
        }

        /// <summary>
        /// Confirms that the OPC UA section binds the endpoint and session settings expected by the bridge.
        /// </summary>
        [Fact]
        public void OpcUa_Section_BindsCorrectly()
        {
            var config = LoadFromJson();
            config.OpcUa.Port.ShouldBe(4840);
            config.OpcUa.EndpointPath.ShouldBe("/LmxOpcUa");
            config.OpcUa.ServerName.ShouldBe("LmxOpcUa");
            config.OpcUa.GalaxyName.ShouldBe("ZB");
            config.OpcUa.MaxSessions.ShouldBe(100);
            config.OpcUa.SessionTimeoutMinutes.ShouldBe(30);
        }

        /// <summary>
        /// Confirms that the MXAccess section binds runtime timeout and reconnect settings correctly.
        /// </summary>
        [Fact]
        public void MxAccess_Section_BindsCorrectly()
        {
            var config = LoadFromJson();
            config.MxAccess.ClientName.ShouldBe("LmxOpcUa");
            config.MxAccess.ReadTimeoutSeconds.ShouldBe(5);
            config.MxAccess.WriteTimeoutSeconds.ShouldBe(5);
            config.MxAccess.MaxConcurrentOperations.ShouldBe(10);
            config.MxAccess.MonitorIntervalSeconds.ShouldBe(5);
            config.MxAccess.AutoReconnect.ShouldBe(true);
            config.MxAccess.ProbeStaleThresholdSeconds.ShouldBe(60);
        }

        /// <summary>
        /// Confirms that the Galaxy repository section binds connection and polling settings correctly.
        /// </summary>
        [Fact]
        public void GalaxyRepository_Section_BindsCorrectly()
        {
            var config = LoadFromJson();
            config.GalaxyRepository.ConnectionString.ShouldContain("ZB");
            config.GalaxyRepository.ChangeDetectionIntervalSeconds.ShouldBe(30);
            config.GalaxyRepository.CommandTimeoutSeconds.ShouldBe(30);
            config.GalaxyRepository.ExtendedAttributes.ShouldBe(false);
        }

        /// <summary>
        /// Confirms that extended-attribute loading defaults to disabled when not configured.
        /// </summary>
        [Fact]
        public void GalaxyRepository_ExtendedAttributes_DefaultsFalse()
        {
            var config = new GalaxyRepositoryConfiguration();
            config.ExtendedAttributes.ShouldBe(false);
        }

        /// <summary>
        /// Confirms that the extended-attribute flag can be enabled through configuration binding.
        /// </summary>
        [Fact]
        public void GalaxyRepository_ExtendedAttributes_BindsFromJson()
        {
            var configuration = new ConfigurationBuilder()
                .AddJsonFile("appsettings.json", optional: false)
                .AddInMemoryCollection(new[] { new System.Collections.Generic.KeyValuePair<string, string>("GalaxyRepository:ExtendedAttributes", "true") })
                .Build();

            var config = new GalaxyRepositoryConfiguration();
            configuration.GetSection("GalaxyRepository").Bind(config);
            config.ExtendedAttributes.ShouldBe(true);
        }

        /// <summary>
        /// Confirms that the dashboard section binds operator-dashboard settings correctly.
        /// </summary>
        [Fact]
        public void Dashboard_Section_BindsCorrectly()
        {
            var config = LoadFromJson();
            config.Dashboard.Enabled.ShouldBe(true);
            config.Dashboard.Port.ShouldBe(8081);
            config.Dashboard.RefreshIntervalSeconds.ShouldBe(10);
        }

        /// <summary>
        /// Confirms that the default configuration objects start with the expected bridge defaults.
        /// </summary>
        [Fact]
        public void DefaultValues_AreCorrect()
        {
            var config = new AppConfiguration();
            config.OpcUa.Port.ShouldBe(4840);
            config.MxAccess.ClientName.ShouldBe("LmxOpcUa");
            config.GalaxyRepository.ChangeDetectionIntervalSeconds.ShouldBe(30);
            config.Dashboard.Enabled.ShouldBe(true);
        }

        /// <summary>
        /// Confirms that a valid configuration passes startup validation.
        /// </summary>
        [Fact]
        public void Validator_ValidConfig_ReturnsTrue()
        {
            var config = LoadFromJson();
            ConfigurationValidator.ValidateAndLog(config).ShouldBe(true);
        }

        /// <summary>
        /// Confirms that an invalid OPC UA port is rejected by startup validation.
        /// </summary>
        [Fact]
        public void Validator_InvalidPort_ReturnsFalse()
        {
            var config = new AppConfiguration();
            config.OpcUa.Port = 0;
            ConfigurationValidator.ValidateAndLog(config).ShouldBe(false);
        }

        /// <summary>
        /// Confirms that an empty Galaxy name is rejected because the bridge requires a namespace target.
        /// </summary>
        [Fact]
        public void Validator_EmptyGalaxyName_ReturnsFalse()
        {
            var config = new AppConfiguration();
            config.OpcUa.GalaxyName = "";
            ConfigurationValidator.ValidateAndLog(config).ShouldBe(false);
        }
    }
}