using NSubstitute;
using ZB.MOM.WW.ScadaBridge.CentralUI.Services;
using ZB.MOM.WW.ScadaBridge.Commons.Entities.Sites;
using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Repositories;
using ZB.MOM.WW.ScadaBridge.Commons.Messages.Health;
using ZB.MOM.WW.ScadaBridge.Commons.Types;
using ZB.MOM.WW.ScadaBridge.Commons.Types.Enums;
using ZB.MOM.WW.ScadaBridge.HealthMonitoring;

namespace ZB.MOM.WW.ScadaBridge.CentralUI.Tests.Services;

/// <summary>
/// M9-T25: unit tests for <see cref="ConnectionHealthQueryService"/>, which projects
/// the site health reports' name-keyed <see cref="SiteHealthReport.DataConnectionStatuses"/>
/// onto a connection-id → <see cref="ConnectionHealth"/> map for the design
/// DataConnections page. The site repository + health aggregator are substituted so
/// the name→id resolution + missing-report / unknown-name tolerance are exercised
/// without any EF Core or cluster traffic.
/// </summary>
public sealed class ConnectionHealthQueryServiceTests
{
    private readonly ISiteRepository _siteRepo = Substitute.For<ISiteRepository>();
    private readonly ICentralHealthAggregator _aggregator = Substitute.For<ICentralHealthAggregator>();

    private ConnectionHealthQueryService CreateService() => new(_siteRepo, _aggregator);

    private void SeedRepos(IEnumerable<Site> sites, IEnumerable<DataConnection> connections)
    {
        _siteRepo.GetAllSitesAsync(Arg.Any<CancellationToken>())
            .Returns(Task.FromResult<IReadOnlyList<Site>>(sites.ToList()));
        _siteRepo.GetAllDataConnectionsAsync(Arg.Any<CancellationToken>())
            .Returns(Task.FromResult<IReadOnlyList<DataConnection>>(connections.ToList()));
    }

    private static SiteHealthState StateWith(
        string siteIdentifier,
        params (string Name, ConnectionHealth Health)[] statuses)
    {
        var dict = statuses.ToDictionary(s => s.Name, s => s.Health);
        return new SiteHealthState
        {
            SiteId = siteIdentifier,
            IsOnline = true,
            LatestReport = MakeReport(siteIdentifier, dict),
        };
    }

    private static SiteHealthReport MakeReport(
        string siteIdentifier,
        IReadOnlyDictionary<string, ConnectionHealth> statuses) =>
        new(
            SiteId: siteIdentifier,
            SequenceNumber: 1,
            ReportTimestamp: DateTimeOffset.UtcNow,
            DataConnectionStatuses: statuses,
            TagResolutionCounts: new Dictionary<string, TagResolutionStatus>(),
            ScriptErrorCount: 0,
            AlarmEvaluationErrorCount: 0,
            StoreAndForwardBufferDepths: new Dictionary<string, int>(),
            DeadLetterCount: 0,
            DeployedInstanceCount: 0,
            EnabledInstanceCount: 0,
            DisabledInstanceCount: 0);

    [Fact]
    public async Task Maps_ConnectionNameStatuses_ToConnectionIds()
    {
        var site = new Site("Plant-A", "plant-a") { Id = 1 };
        var plc1 = new DataConnection("PLC-1", "OpcUa", 1) { Id = 100 };
        var rtu9 = new DataConnection("RTU-9", "Custom", 1) { Id = 200 };
        SeedRepos(new[] { site }, new[] { plc1, rtu9 });
        _aggregator.GetSiteState("plant-a").Returns(
            StateWith("plant-a",
                ("PLC-1", ConnectionHealth.Connected),
                ("RTU-9", ConnectionHealth.Disconnected)));

        var map = await CreateService().GetConnectionHealthAsync();

        Assert.Equal(ConnectionHealth.Connected, map[100]);
        Assert.Equal(ConnectionHealth.Disconnected, map[200]);
        Assert.Equal(2, map.Count);
    }

    [Fact]
    public async Task MissingReport_YieldsNoEntriesForThatSite()
    {
        var site = new Site("Plant-A", "plant-a") { Id = 1 };
        var plc1 = new DataConnection("PLC-1", "OpcUa", 1) { Id = 100 };
        SeedRepos(new[] { site }, new[] { plc1 });
        // No state tracked for the site yet (just-started central / no report).
        _aggregator.GetSiteState("plant-a").Returns((SiteHealthState?)null);

        var map = await CreateService().GetConnectionHealthAsync();

        Assert.Empty(map);
    }

    [Fact]
    public async Task StateWithoutLatestReport_YieldsNoEntries()
    {
        var site = new Site("Plant-A", "plant-a") { Id = 1 };
        var plc1 = new DataConnection("PLC-1", "OpcUa", 1) { Id = 100 };
        SeedRepos(new[] { site }, new[] { plc1 });
        // Heartbeat-only state: site is tracked but has not sent a full report.
        _aggregator.GetSiteState("plant-a").Returns(
            new SiteHealthState { SiteId = "plant-a", IsOnline = true, LatestReport = null });

        var map = await CreateService().GetConnectionHealthAsync();

        Assert.Empty(map);
    }

    [Fact]
    public async Task UnknownConnectionName_IsSkipped()
    {
        var site = new Site("Plant-A", "plant-a") { Id = 1 };
        var plc1 = new DataConnection("PLC-1", "OpcUa", 1) { Id = 100 };
        SeedRepos(new[] { site }, new[] { plc1 });
        // Report references a connection name with no matching DataConnection row
        // (e.g. a connection deleted centrally but still live at the site).
        _aggregator.GetSiteState("plant-a").Returns(
            StateWith("plant-a",
                ("PLC-1", ConnectionHealth.Connected),
                ("GHOST", ConnectionHealth.Error)));

        var map = await CreateService().GetConnectionHealthAsync();

        Assert.Equal(ConnectionHealth.Connected, map[100]);
        Assert.Single(map);
    }

    [Fact]
    public async Task ResolvesNamesPerSite_NotGloballyAmbiguous()
    {
        // Two sites each own a connection named "PLC-1". The name→id resolution
        // must be scoped to the report's own site so the right id is stamped.
        var siteA = new Site("Plant-A", "plant-a") { Id = 1 };
        var siteB = new Site("Plant-B", "plant-b") { Id = 2 };
        var aPlc = new DataConnection("PLC-1", "OpcUa", 1) { Id = 100 };
        var bPlc = new DataConnection("PLC-1", "OpcUa", 2) { Id = 200 };
        SeedRepos(new[] { siteA, siteB }, new[] { aPlc, bPlc });
        _aggregator.GetSiteState("plant-a").Returns(
            StateWith("plant-a", ("PLC-1", ConnectionHealth.Connected)));
        _aggregator.GetSiteState("plant-b").Returns(
            StateWith("plant-b", ("PLC-1", ConnectionHealth.Connecting)));

        var map = await CreateService().GetConnectionHealthAsync();

        Assert.Equal(ConnectionHealth.Connected, map[100]);
        Assert.Equal(ConnectionHealth.Connecting, map[200]);
    }
}
