using System.Collections.Generic;
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", 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);
            configuration.GetSection("Security").Bind(config.Security);
            configuration.GetSection("Historian").Bind(config.Historian);
            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.BindAddress.ShouldBe("0.0.0.0");
            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", false)
                .AddInMemoryCollection(new[]
                    { new 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.BindAddress.ShouldBe("0.0.0.0");
            config.OpcUa.Port.ShouldBe(4840);
            config.MxAccess.ClientName.ShouldBe("LmxOpcUa");
            config.GalaxyRepository.ChangeDetectionIntervalSeconds.ShouldBe(30);
            config.Dashboard.Enabled.ShouldBe(true);
        }

        /// <summary>
        ///     Confirms that BindAddress can be overridden to a specific hostname or IP.
        /// </summary>
        [Fact]
        public void OpcUa_BindAddress_CanBeOverridden()
        {
            var configuration = new ConfigurationBuilder()
                .AddInMemoryCollection(new[]
                {
                    new KeyValuePair<string, string>("OpcUa:BindAddress", "localhost")
                })
                .Build();

            var config = new OpcUaConfiguration();
            configuration.GetSection("OpcUa").Bind(config);
            config.BindAddress.ShouldBe("localhost");
        }

        /// <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);
        }

        /// <summary>
        ///     Confirms that the Security section binds profile list from appsettings.json.
        /// </summary>
        [Fact]
        public void Security_Section_BindsProfilesCorrectly()
        {
            var config = LoadFromJson();
            config.Security.Profiles.ShouldContain("None");
            config.Security.AutoAcceptClientCertificates.ShouldBe(true);
            config.Security.MinimumCertificateKeySize.ShouldBe(2048);
        }

        /// <summary>
        ///     Stability review 2026-04-13 Finding 3: MxAccess.RequestTimeoutSeconds must be at
        ///     least 1. Zero or negative values disable the safety bound and are rejected.
        /// </summary>
        [Fact]
        public void Validator_MxAccessRequestTimeoutZero_ReturnsFalse()
        {
            var config = LoadFromJson();
            config.MxAccess.RequestTimeoutSeconds = 0;
            ConfigurationValidator.ValidateAndLog(config).ShouldBe(false);
        }

        /// <summary>
        ///     Stability review 2026-04-13 Finding 3: Historian.RequestTimeoutSeconds must be at
        ///     least 1 when historian is enabled.
        /// </summary>
        [Fact]
        public void Validator_HistorianRequestTimeoutZero_ReturnsFalse()
        {
            var config = LoadFromJson();
            config.Historian.Enabled = true;
            config.Historian.ServerName = "localhost";
            config.Historian.RequestTimeoutSeconds = 0;
            ConfigurationValidator.ValidateAndLog(config).ShouldBe(false);
        }

        /// <summary>
        ///     Confirms the bound AppConfiguration carries non-zero default request timeouts.
        /// </summary>
        [Fact]
        public void Validator_DefaultRequestTimeouts_AreSensible()
        {
            var config = new AppConfiguration();
            config.MxAccess.RequestTimeoutSeconds.ShouldBeGreaterThanOrEqualTo(1);
            config.Historian.RequestTimeoutSeconds.ShouldBeGreaterThanOrEqualTo(1);
        }

        /// <summary>
        ///     Confirms that a minimum key size below 2048 is rejected by the validator.
        /// </summary>
        [Fact]
        public void Validator_InvalidMinKeySize_ReturnsFalse()
        {
            var config = new AppConfiguration();
            config.Security.MinimumCertificateKeySize = 1024;
            ConfigurationValidator.ValidateAndLog(config).ShouldBe(false);
        }

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

        /// <summary>
        ///     Confirms that custom security profiles can be bound from in-memory configuration.
        /// </summary>
        [Fact]
        public void Security_Section_BindsCustomProfiles()
        {
            var configuration = new ConfigurationBuilder()
                .AddInMemoryCollection(new[]
                {
                    new KeyValuePair<string, string>("Security:Profiles:0", "None"),
                    new KeyValuePair<string, string>("Security:Profiles:1", "Basic256Sha256-SignAndEncrypt"),
                    new KeyValuePair<string, string>("Security:AutoAcceptClientCertificates", "false"),
                    new KeyValuePair<string, string>("Security:MinimumCertificateKeySize", "4096")
                })
                .Build();

            // Clear default list before binding to match production behavior
            var config = new AppConfiguration();
            config.Security.Profiles.Clear();
            configuration.GetSection("Security").Bind(config.Security);

            config.Security.Profiles.Count.ShouldBe(2);
            config.Security.Profiles.ShouldContain("None");
            config.Security.Profiles.ShouldContain("Basic256Sha256-SignAndEncrypt");
            config.Security.AutoAcceptClientCertificates.ShouldBe(false);
            config.Security.MinimumCertificateKeySize.ShouldBe(4096);
        }

        [Fact]
        public void Redundancy_Section_BindsFromJson()
        {
            var config = LoadFromJson();
            config.Redundancy.Enabled.ShouldBe(false);
            config.Redundancy.Mode.ShouldBe("Warm");
            config.Redundancy.Role.ShouldBe("Primary");
            config.Redundancy.ServiceLevelBase.ShouldBe(200);
        }

        [Fact]
        public void Redundancy_Section_BindsCustomValues()
        {
            var configuration = new ConfigurationBuilder()
                .AddInMemoryCollection(new[]
                {
                    new KeyValuePair<string, string>("Redundancy:Enabled", "true"),
                    new KeyValuePair<string, string>("Redundancy:Mode", "Hot"),
                    new KeyValuePair<string, string>("Redundancy:Role", "Secondary"),
                    new KeyValuePair<string, string>("Redundancy:ServiceLevelBase", "180"),
                    new KeyValuePair<string, string>("Redundancy:ServerUris:0", "urn:a"),
                    new KeyValuePair<string, string>("Redundancy:ServerUris:1", "urn:b")
                })
                .Build();

            var config = new AppConfiguration();
            configuration.GetSection("Redundancy").Bind(config.Redundancy);

            config.Redundancy.Enabled.ShouldBe(true);
            config.Redundancy.Mode.ShouldBe("Hot");
            config.Redundancy.Role.ShouldBe("Secondary");
            config.Redundancy.ServiceLevelBase.ShouldBe(180);
            config.Redundancy.ServerUris.Count.ShouldBe(2);
        }

        [Fact]
        public void Validator_RedundancyEnabled_NoApplicationUri_ReturnsFalse()
        {
            var config = new AppConfiguration();
            config.Redundancy.Enabled = true;
            config.Redundancy.ServerUris.Add("urn:a");
            config.Redundancy.ServerUris.Add("urn:b");
            // OpcUa.ApplicationUri is null
            ConfigurationValidator.ValidateAndLog(config).ShouldBe(false);
        }

        [Fact]
        public void Validator_InvalidServiceLevelBase_ReturnsFalse()
        {
            var config = new AppConfiguration();
            config.Redundancy.ServiceLevelBase = 0;
            ConfigurationValidator.ValidateAndLog(config).ShouldBe(false);
        }

        [Fact]
        public void OpcUa_ApplicationUri_DefaultsToNull()
        {
            var config = new OpcUaConfiguration();
            config.ApplicationUri.ShouldBeNull();
        }

        [Fact]
        public void OpcUa_ApplicationUri_BindsFromConfig()
        {
            var configuration = new ConfigurationBuilder()
                .AddInMemoryCollection(new[]
                {
                    new KeyValuePair<string, string>("OpcUa:ApplicationUri", "urn:test:app")
                })
                .Build();

            var config = new OpcUaConfiguration();
            configuration.GetSection("OpcUa").Bind(config);
            config.ApplicationUri.ShouldBe("urn:test:app");
        }

        [Fact]
        public void Historian_Section_BindsFromJson()
        {
            var config = LoadFromJson();
            config.Historian.Enabled.ShouldBe(false);
            config.Historian.ServerName.ShouldBe("localhost");
            config.Historian.IntegratedSecurity.ShouldBe(true);
            config.Historian.Port.ShouldBe(32568);
            config.Historian.CommandTimeoutSeconds.ShouldBe(30);
            config.Historian.MaxValuesPerRead.ShouldBe(10000);
        }

        [Fact]
        public void Historian_Section_BindsCustomValues()
        {
            var configuration = new ConfigurationBuilder()
                .AddInMemoryCollection(new[]
                {
                    new KeyValuePair<string, string>("Historian:Enabled", "true"),
                    new KeyValuePair<string, string>("Historian:ServerName", "historian-server"),
                    new KeyValuePair<string, string>("Historian:IntegratedSecurity", "false"),
                    new KeyValuePair<string, string>("Historian:UserName", "testuser"),
                    new KeyValuePair<string, string>("Historian:Password", "testpass"),
                    new KeyValuePair<string, string>("Historian:Port", "12345"),
                    new KeyValuePair<string, string>("Historian:CommandTimeoutSeconds", "60"),
                    new KeyValuePair<string, string>("Historian:MaxValuesPerRead", "5000")
                })
                .Build();

            var config = new HistorianConfiguration();
            configuration.GetSection("Historian").Bind(config);

            config.Enabled.ShouldBe(true);
            config.ServerName.ShouldBe("historian-server");
            config.IntegratedSecurity.ShouldBe(false);
            config.UserName.ShouldBe("testuser");
            config.Password.ShouldBe("testpass");
            config.Port.ShouldBe(12345);
            config.CommandTimeoutSeconds.ShouldBe(60);
            config.MaxValuesPerRead.ShouldBe(5000);
        }

        [Fact]
        public void Validator_HistorianEnabled_EmptyServerName_ReturnsFalse()
        {
            var config = new AppConfiguration();
            config.Historian.Enabled = true;
            config.Historian.ServerName = "";
            ConfigurationValidator.ValidateAndLog(config).ShouldBe(false);
        }

        [Fact]
        public void Validator_HistorianEnabled_InvalidPort_ReturnsFalse()
        {
            var config = new AppConfiguration();
            config.Historian.Enabled = true;
            config.Historian.Port = 0;
            ConfigurationValidator.ValidateAndLog(config).ShouldBe(false);
        }

        [Fact]
        public void Validator_HistorianEnabled_NoIntegratedSecurity_EmptyUserName_ReturnsFalse()
        {
            var config = new AppConfiguration();
            config.Historian.Enabled = true;
            config.Historian.IntegratedSecurity = false;
            config.Historian.UserName = "";
            ConfigurationValidator.ValidateAndLog(config).ShouldBe(false);
        }
    }
}