using System.Security.Claims;
using Bunit;
using Microsoft.AspNetCore.Components.Authorization;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Extensions.Options;
using NSubstitute;
using ZB.MOM.WW.ScadaBridge.CentralUI.Components.Shared;
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.Interfaces.Services;
using ZB.MOM.WW.ScadaBridge.Communication;
using ZB.MOM.WW.ScadaBridge.DeploymentManager;
using ZB.MOM.WW.ScadaBridge.DeploymentManager.PendingUpdates;
using SitesPage = ZB.MOM.WW.ScadaBridge.CentralUI.Components.Pages.Admin.Sites;

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

/// <summary>
/// Regression tests for CentralUI-012. The Sites page loaded all sites and then
/// issued <c>GetDataConnectionsBySiteIdAsync</c> once per site (N+1 database
/// round-trips on every load and post-delete refresh). The fix fetches all
/// data connections in a single <c>GetAllDataConnectionsAsync</c> call and
/// groups them client-side.
/// </summary>
public class SitesPageTests : BunitContext
{
    private readonly ISiteRepository _siteRepo = Substitute.For<ISiteRepository>();
    private readonly IPendingUpdatesCache _pendingUpdates = Substitute.For<IPendingUpdatesCache>();

    private void RegisterServices()
    {
        Services.AddSingleton(_siteRepo);

        // Default: an empty snapshot, so the page's badges resolve without a stub.
        // Individual tests re-stub GetAsync before rendering.
        _pendingUpdates.GetAsync(Arg.Any<bool>(), Arg.Any<CancellationToken>())
            .Returns(_ => Task.FromResult(Snapshot()));
        Services.AddSingleton(_pendingUpdates);

        var comms = new CommunicationService(
            Options.Create(new CommunicationOptions()),
            NullLogger<CommunicationService>.Instance);
        Services.AddSingleton(comms);

        var artifactSvc = new ArtifactDeploymentService(
            _siteRepo,
            Substitute.For<IDeploymentManagerRepository>(),
            Substitute.For<ITemplateEngineRepository>(),
            Substitute.For<IExternalSystemRepository>(),
            Substitute.For<INotificationRepository>(),
            comms,
            Substitute.For<IAuditService>(),
            Options.Create(new DeploymentManagerOptions()),
            NullLogger<ArtifactDeploymentService>.Instance,
            new ArtifactRevisionHashService());
        Services.AddSingleton(artifactSvc);

        Services.AddSingleton<IDialogService>(Substitute.For<IDialogService>());

        var identity = new ClaimsIdentity(
            new[] { new Claim(ClaimTypes.Name, "admin") }, "TestCookie");
        var authState = new AuthenticationState(new ClaimsPrincipal(identity));
        Services.AddSingleton<AuthenticationStateProvider>(
            new StubAuthStateProvider(authState));
    }

    private sealed class StubAuthStateProvider : AuthenticationStateProvider
    {
        private readonly AuthenticationState _state;
        public StubAuthStateProvider(AuthenticationState state) => _state = state;
        public override Task<AuthenticationState> GetAuthenticationStateAsync()
            => Task.FromResult(_state);
    }

    private static List<Site> Sites(params int[] ids)
        => ids.Select(id => new Site($"Site{id}", $"SITE-{id}") { Id = id }).ToList();

    private static DataConnection Conn(int siteId, string name)
        => new(name, "OpcUa", siteId);

    private static PendingUpdatesSnapshot Snapshot(params SitePendingUpdates[] sites)
        => new(new DateTimeOffset(2026, 9, 14, 10, 30, 0, TimeSpan.Zero), sites);

    private static SitePendingUpdates Pending(
        int siteId,
        ArtifactDeploymentState state,
        int deployed = 0,
        int stale = 0,
        int unknown = 0)
        => new(
            siteId,
            $"SITE-{siteId}",
            $"Site{siteId}",
            state,
            state == ArtifactDeploymentState.NeverDeployed
                ? null
                : new DateTimeOffset(2026, 9, 13, 8, 0, 0, TimeSpan.Zero),
            deployed,
            stale,
            unknown);

    [Fact]
    public void LoadData_FetchesAllConnectionsInOneQuery_NoPerSiteQueries()
    {
        RegisterServices();
        _siteRepo.GetAllSitesAsync().Returns(Sites(1, 2, 3));
        _siteRepo.GetAllDataConnectionsAsync().Returns(new List<DataConnection>
        {
            Conn(1, "c1"), Conn(2, "c2"), Conn(3, "c3"),
        });

        Render<SitesPage>();

        // Regression: exactly one bulk query, and zero per-site queries.
        _siteRepo.Received(1).GetAllDataConnectionsAsync();
        _siteRepo.DidNotReceive().GetDataConnectionsBySiteIdAsync(Arg.Any<int>());
    }

    [Fact]
    public void LoadData_GroupsConnectionsBySite_AndRendersThem()
    {
        RegisterServices();
        _siteRepo.GetAllSitesAsync().Returns(Sites(1, 2));
        _siteRepo.GetAllDataConnectionsAsync().Returns(new List<DataConnection>
        {
            Conn(1, "alpha-conn"), Conn(2, "beta-conn"),
        });

        var cut = Render<SitesPage>();

        Assert.Contains("alpha-conn", cut.Markup);
        Assert.Contains("beta-conn", cut.Markup);
    }

    [Fact]
    public void ArtifactBadge_ShowsCurrent_OutOfDate_NeverDeployed()
    {
        RegisterServices();
        _siteRepo.GetAllSitesAsync().Returns(Sites(1, 2, 3));
        _siteRepo.GetAllDataConnectionsAsync().Returns(new List<DataConnection>());
        _pendingUpdates.GetAsync(Arg.Any<bool>(), Arg.Any<CancellationToken>())
            .Returns(_ => Task.FromResult(Snapshot(
                Pending(1, ArtifactDeploymentState.Current),
                Pending(2, ArtifactDeploymentState.OutOfDate),
                Pending(3, ArtifactDeploymentState.NeverDeployed))));

        var cut = Render<SitesPage>();

        cut.WaitForAssertion(() =>
        {
            Assert.Contains("aria-label=\"Artifacts: current\"", cut.Markup);
            Assert.Contains("Artifacts current", cut.Markup);
            Assert.Contains("aria-label=\"Artifacts: out of date\"", cut.Markup);
            Assert.Contains("Artifacts out of date", cut.Markup);
            Assert.Contains("aria-label=\"Artifacts: never deployed\"", cut.Markup);
            Assert.Contains("Artifacts never deployed", cut.Markup);
        });
    }

    [Fact]
    public void InstanceLine_ShowsStaleOfDeployed()
    {
        RegisterServices();
        _siteRepo.GetAllSitesAsync().Returns(Sites(1));
        _siteRepo.GetAllDataConnectionsAsync().Returns(new List<DataConnection>());
        _pendingUpdates.GetAsync(Arg.Any<bool>(), Arg.Any<CancellationToken>())
            .Returns(_ => Task.FromResult(Snapshot(
                Pending(1, ArtifactDeploymentState.Current, deployed: 5, stale: 2, unknown: 1))));

        var cut = Render<SitesPage>();

        cut.WaitForAssertion(() =>
        {
            Assert.Contains("2 of 5 instances out of date", cut.Markup);
            Assert.Contains("1 could not be evaluated", cut.Markup);
            Assert.Contains("/deployment/topology", cut.Markup);
        });
    }

    [Fact]
    public void InstanceLine_PluralisesTheSingleInstanceCase()
    {
        RegisterServices();
        _siteRepo.GetAllSitesAsync().Returns(Sites(1, 2));
        _siteRepo.GetAllDataConnectionsAsync().Returns(new List<DataConnection>());
        _pendingUpdates.GetAsync(Arg.Any<bool>(), Arg.Any<CancellationToken>())
            .Returns(_ => Task.FromResult(Snapshot(
                Pending(1, ArtifactDeploymentState.Current, deployed: 1, stale: 1),
                Pending(2, ArtifactDeploymentState.Current, deployed: 1))));

        var cut = Render<SitesPage>();

        cut.WaitForAssertion(() =>
        {
            Assert.Contains("1 of 1 instance out of date", cut.Markup);
            Assert.Contains("All 1 instance current", cut.Markup);
            Assert.DoesNotContain("1 instances", cut.Markup);
        });
    }

    [Fact]
    public void Recheck_ForcesRefresh()
    {
        RegisterServices();
        _siteRepo.GetAllSitesAsync().Returns(Sites(1));
        _siteRepo.GetAllDataConnectionsAsync().Returns(new List<DataConnection>());

        var cut = Render<SitesPage>();
        cut.Find("button[aria-label=\"Re-check pending updates\"]").Click();

        cut.WaitForAssertion(() =>
            _pendingUpdates.Received().GetAsync(true, Arg.Any<CancellationToken>()));
    }

    [Fact]
    public void SiteLoadFailure_SkipsTheFleetEvaluation()
    {
        RegisterServices();
        _siteRepo.GetAllSitesAsync()
            .Returns<Task<IReadOnlyList<Site>>>(_ => throw new InvalidOperationException("db down"));

        var cut = Render<SitesPage>();

        cut.WaitForAssertion(() => Assert.Contains("Failed to load sites", cut.Markup));
        // No cards to badge, so the whole-fleet flatten must not run at all.
        _pendingUpdates.DidNotReceive().GetAsync(Arg.Any<bool>(), Arg.Any<CancellationToken>());
    }

    [Fact]
    public void FailedRecheck_ClearsTheStaleAsOfCaption()
    {
        RegisterServices();
        _siteRepo.GetAllSitesAsync().Returns(Sites(1));
        _siteRepo.GetAllDataConnectionsAsync().Returns(new List<DataConnection>());
        _pendingUpdates.GetAsync(Arg.Any<bool>(), Arg.Any<CancellationToken>())
            .Returns(_ => Task.FromResult(Snapshot(Pending(1, ArtifactDeploymentState.Current))));

        var cut = Render<SitesPage>();
        cut.WaitForAssertion(() => Assert.Contains("Updates as of", cut.Markup));

        // The re-check now faults: the error wins, so the caption from the earlier good
        // evaluation must not stand next to "unavailable" badges.
        _pendingUpdates.GetAsync(Arg.Any<bool>(), Arg.Any<CancellationToken>())
            .Returns<Task<PendingUpdatesSnapshot>>(_ => throw new InvalidOperationException("evaluator down"));
        cut.Find("button[aria-label=\"Re-check pending updates\"]").Click();

        cut.WaitForAssertion(() =>
        {
            Assert.DoesNotContain("Updates as of", cut.Markup);
            Assert.Contains("Artifacts: unavailable", cut.Markup);
            Assert.Contains("Site1", cut.Markup);
        });
    }

    [Fact]
    public void CacheFault_ShowsUnavailable_AndSitesStillRender()
    {
        RegisterServices();
        _siteRepo.GetAllSitesAsync().Returns(Sites(1, 2));
        _siteRepo.GetAllDataConnectionsAsync().Returns(new List<DataConnection>());
        _pendingUpdates.GetAsync(Arg.Any<bool>(), Arg.Any<CancellationToken>())
            .Returns<Task<PendingUpdatesSnapshot>>(_ => throw new InvalidOperationException("evaluator down"));

        var cut = Render<SitesPage>();

        cut.WaitForAssertion(() =>
        {
            // The snapshot failing must never take the site list down with it.
            Assert.Contains("Site1", cut.Markup);
            Assert.Contains("Site2", cut.Markup);
            Assert.Contains("Artifacts: unavailable", cut.Markup);
        });
    }
}