using System;
using Shouldly;
using Xunit;
using ZB.MOM.WW.LmxOpcUa.Host.Domain;
using ZB.MOM.WW.LmxOpcUa.Host.GalaxyRepository;
using ZB.MOM.WW.LmxOpcUa.Host.Metrics;
using ZB.MOM.WW.LmxOpcUa.Host.Status;
using ZB.MOM.WW.LmxOpcUa.Tests.Helpers;

namespace ZB.MOM.WW.LmxOpcUa.Tests.Status
{
    /// <summary>
    /// Verifies the HTML, JSON, and health snapshots generated for the operator status dashboard.
    /// </summary>
    public class StatusReportServiceTests
    {
        /// <summary>
        /// Confirms that the generated HTML contains every dashboard panel expected by operators.
        /// </summary>
        [Fact]
        public void GenerateHtml_ContainsAllPanels()
        {
            var sut = CreateService();
            var html = sut.GenerateHtml();

            html.ShouldContain("Connection");
            html.ShouldContain("Health");
            html.ShouldContain("Subscriptions");
            html.ShouldContain("Galaxy Info");
            html.ShouldContain("Operations");
            html.ShouldContain("Footer");
        }

        /// <summary>
        /// Confirms that the generated HTML includes the configured auto-refresh meta tag.
        /// </summary>
        [Fact]
        public void GenerateHtml_ContainsMetaRefresh()
        {
            var sut = CreateService();
            var html = sut.GenerateHtml();
            html.ShouldContain("meta http-equiv='refresh' content='10'");
        }

        /// <summary>
        /// Confirms that the connection panel renders the current runtime connection state.
        /// </summary>
        [Fact]
        public void GenerateHtml_ConnectionPanel_ShowsState()
        {
            var sut = CreateService();
            var html = sut.GenerateHtml();
            html.ShouldContain("Connected");
        }

        /// <summary>
        /// Confirms that the Galaxy panel renders the bridged Galaxy name.
        /// </summary>
        [Fact]
        public void GenerateHtml_GalaxyPanel_ShowsName()
        {
            var sut = CreateService();
            var html = sut.GenerateHtml();
            html.ShouldContain("TestGalaxy");
        }

        /// <summary>
        /// Confirms that the operations table renders the expected performance metric headers.
        /// </summary>
        [Fact]
        public void GenerateHtml_OperationsTable_ShowsHeaders()
        {
            var sut = CreateService();
            var html = sut.GenerateHtml();
            html.ShouldContain("Count");
            html.ShouldContain("Success Rate");
            html.ShouldContain("Avg (ms)");
            html.ShouldContain("Min (ms)");
            html.ShouldContain("Max (ms)");
            html.ShouldContain("P95 (ms)");
        }

        /// <summary>
        /// Confirms that the footer renders timestamp and version information.
        /// </summary>
        [Fact]
        public void GenerateHtml_Footer_ContainsTimestampAndVersion()
        {
            var sut = CreateService();
            var html = sut.GenerateHtml();
            html.ShouldContain("Generated:");
            html.ShouldContain("Version:");
        }

        /// <summary>
        /// Confirms that the generated JSON includes the major dashboard sections.
        /// </summary>
        [Fact]
        public void GenerateJson_Deserializes()
        {
            var sut = CreateService();
            var json = sut.GenerateJson();

            json.ShouldNotBeNullOrWhiteSpace();
            json.ShouldContain("Connection");
            json.ShouldContain("Health");
            json.ShouldContain("Subscriptions");
            json.ShouldContain("Galaxy");
            json.ShouldContain("Operations");
            json.ShouldContain("Footer");
        }

        /// <summary>
        /// Confirms that the report service reports healthy when the runtime connection is up.
        /// </summary>
        [Fact]
        public void IsHealthy_WhenConnected_ReturnsTrue()
        {
            var sut = CreateService();
            sut.IsHealthy().ShouldBe(true);
        }

        /// <summary>
        /// Confirms that the report service reports unhealthy when the runtime connection is down.
        /// </summary>
        [Fact]
        public void IsHealthy_WhenDisconnected_ReturnsFalse()
        {
            var mxClient = new FakeMxAccessClient { State = ConnectionState.Disconnected };
            var sut = new StatusReportService(new HealthCheckService(), 10);
            sut.SetComponents(mxClient, null, null, null);
            sut.IsHealthy().ShouldBe(false);
        }

        /// <summary>
        /// Creates a status report service preloaded with representative runtime, Galaxy, and metrics data.
        /// </summary>
        /// <returns>A configured status report service for dashboard assertions.</returns>
        private static StatusReportService CreateService()
        {
            var mxClient = new FakeMxAccessClient();
            using var metrics = new PerformanceMetrics();
            metrics.RecordOperation("Read", TimeSpan.FromMilliseconds(10));
            metrics.RecordOperation("Write", TimeSpan.FromMilliseconds(20));

            var galaxyStats = new GalaxyRepositoryStats
            {
                GalaxyName = "TestGalaxy",
                DbConnected = true,
                LastDeployTime = new DateTime(2024, 6, 1),
                ObjectCount = 42,
                AttributeCount = 200,
                LastRebuildTime = DateTime.UtcNow
            };

            var sut = new StatusReportService(new HealthCheckService(), 10);
            sut.SetComponents(mxClient, metrics, galaxyStats, null);
            return sut;
        }
    }
}