using System.Reflection;
using System.Runtime.ExceptionServices;
using Microsoft.AspNetCore.Components;
using Microsoft.AspNetCore.Components.RenderTree;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging.Abstractions;
using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.AdminUI.Browsing;
using ZB.MOM.WW.OtOpcUa.AdminUI.Components.Shared.Raw;
using ZB.MOM.WW.OtOpcUa.AdminUI.Tests.Uns;
using ZB.MOM.WW.OtOpcUa.AdminUI.Uns;
using ZB.MOM.WW.OtOpcUa.Commons.Browsing;
using ZB.MOM.WW.OtOpcUa.Configuration;
using ZB.MOM.WW.OtOpcUa.Configuration.Entities;

namespace ZB.MOM.WW.OtOpcUa.AdminUI.Tests.Raw;

/// <summary>
///     Pins that a superseded open of the browse modal can never write its device's browse context under
///     a different device's displayed modal.
/// </summary>
/// <remarks>
///     <para>
///         Blazor does not serialize <c>OnParametersSetAsync</c> against its own outstanding task, and the
///         modal's <c>_open</c> bool cannot tell two opens apart. Its resolve awaits the merged probe
///         config and the target group context, so without a post-await staleness re-check a
///         close-reopen onto another device lets the first open's late continuation install its
///         <c>_driverType</c> / <c>_mergedConfig</c> / <c>_groupPrefix</c> — and "Connect &amp; browse"
///         would then silently dial the wrong controller and commit under the wrong group. Same race, same
///         fix as the two sibling modals (<c>RawTagModal</c>, <c>RawManualTagEntryModal</c>, 2026-08-05).
///     </para>
///     <para>
///         AdminUI has no bUnit, so the component is driven directly as a class: its injected properties,
///         its <c>[Parameter]</c>s (BL0005 forbids setting those from outside the component, and this
///         project treats warnings as errors) and its private resolve state are reached by reflection.
///         Unlike the siblings this modal calls <c>StateHasChanged</c> on the open path, which throws
///         unless the component holds a render handle — hence the inert renderer below.
///     </para>
/// </remarks>
// BL0006 warns off Microsoft.AspNetCore.Components.RenderTree, which is right for production code and
// unavoidable here: subclassing Renderer is the only way to hand a component a render handle without
// taking a bUnit dependency, and Renderer's abstract render method is typed in that namespace. The surface
// used is that one parameter — no RenderTree type is inspected, stored or asserted on.
#pragma warning disable BL0006
public sealed class RawBrowseModalStaleOpenTests : IDisposable
{
    private const string ConfigA = """{"endpoint":"10.0.0.1:44818","slot":0}""";
    private const string ConfigB = """{"endpoint":"10.0.0.2:44818","slot":1}""";

    private readonly List<InertRenderer> _renderers = new();

    [Fact]
    public async Task A_stale_open_never_feeds_the_browser_another_devices_config()
    {
        var deviceAResolve = new TaskCompletionSource();
        var svc = new FakeRawTreeService
        {
            OnLoadMergedProbeConfigAsync = async deviceId =>
            {
                if (deviceId == "dev-A") { await deviceAResolve.Task; return ("AbCip", ConfigA); }
                return ("TwinCAT", ConfigB);
            },
        };

        var modal = NewModal(svc, new FakeBrowserSessionService(), NullExportReader());

        // Quick close-reopen onto another device while dev-A's resolve is still in flight.
        SetParameters(modal, visible: true, deviceId: "dev-A", tagGroupId: null);
        var staleOpen = OpenAsync(modal);

        SetParameters(modal, visible: false, deviceId: "dev-A", tagGroupId: null);
        await OpenAsync(modal);

        SetParameters(modal, visible: true, deviceId: "dev-B", tagGroupId: null);
        await OpenAsync(modal);

        deviceAResolve.SetResult();
        await staleOpen;

        Field<string>(modal, "_mergedConfig").ShouldBe(ConfigB);
        Field<string>(modal, "_driverType").ShouldBe("TwinCAT");
    }

    [Fact]
    public async Task A_stale_group_resolve_never_retargets_the_displayed_open()
    {
        var dbName = SeedGroup("TG-A", deviceId: "dev-A", name: "GroupA");
        var groupResolve = new TaskCompletionSource();

        var svc = new FakeRawTreeService
        {
            OnLoadMergedProbeConfig = deviceId =>
                deviceId == "dev-A" ? ("AbCip", ConfigA) : null,
        };

        var modal = NewModal(
            svc,
            new FakeBrowserSessionService(),
            new RawTagCsvExportReader(new GatedDbContextFactory(dbName, groupResolve.Task)));

        // The merged-config resolve completes inline here, so this open suspends inside the GROUP
        // resolve — the second await, which a fix that guards only the first one leaves unprotected.
        SetParameters(modal, visible: true, deviceId: "dev-A", tagGroupId: "TG-A");
        var staleOpen = OpenAsync(modal);

        SetParameters(modal, visible: false, deviceId: "dev-A", tagGroupId: "TG-A");
        await OpenAsync(modal);

        // Re-opened with no device and no target group: the displayed open commits at a device root it
        // has not resolved yet, so both writes the stale continuation makes are observable.
        SetParameters(modal, visible: true, deviceId: "", tagGroupId: null);
        await OpenAsync(modal);

        groupResolve.SetResult();
        await staleOpen;

        Field<string?>(modal, "_groupPrefix").ShouldBeNull();
        Field<string>(modal, "_effectiveDeviceId").ShouldBe("");
    }

    [Fact]
    public async Task A_stale_open_completing_late_never_clears_the_live_opens_loading_state()
    {
        var deviceAResolve = new TaskCompletionSource();
        var deviceBResolve = new TaskCompletionSource();
        var svc = new FakeRawTreeService
        {
            OnLoadMergedProbeConfigAsync = async deviceId =>
            {
                if (deviceId == "dev-A") { await deviceAResolve.Task; return ("AbCip", ConfigA); }
                await deviceBResolve.Task;
                return ("TwinCAT", ConfigB);
            },
        };

        var modal = NewModal(svc, new FakeBrowserSessionService(), NullExportReader());

        SetParameters(modal, visible: true, deviceId: "dev-A", tagGroupId: null);
        var staleOpen = OpenAsync(modal);

        SetParameters(modal, visible: false, deviceId: "dev-A", tagGroupId: null);
        await OpenAsync(modal);

        SetParameters(modal, visible: true, deviceId: "dev-B", tagGroupId: null);
        var liveOpen = OpenAsync(modal);

        // The stale run finishes while the live one is still resolving. Its tail state — the spinner
        // flag and the render it forces — belongs to an open that is no longer displayed: letting the
        // `finally` run would drop the live open's spinner and paint the not-yet-resolved
        // "Browsing unavailable" panel over a device that is still loading.
        deviceAResolve.SetResult();
        await staleOpen;

        Field<bool>(modal, "_resolving").ShouldBeTrue();

        deviceBResolve.SetResult();
        await liveOpen;

        Field<bool>(modal, "_resolving").ShouldBeFalse();
    }

    [Fact]
    public async Task A_stale_resolve_failure_never_paints_its_error_over_the_live_open()
    {
        var deviceAResolve = new TaskCompletionSource();
        var svc = new FakeRawTreeService
        {
            OnLoadMergedProbeConfigAsync = async deviceId =>
            {
                if (deviceId == "dev-A") { await deviceAResolve.Task; return ("AbCip", ConfigA); }
                return ("TwinCAT", ConfigB);
            },
        };

        var modal = NewModal(svc, new FakeBrowserSessionService(), NullExportReader());

        SetParameters(modal, visible: true, deviceId: "dev-A", tagGroupId: null);
        var staleOpen = OpenAsync(modal);

        SetParameters(modal, visible: false, deviceId: "dev-A", tagGroupId: null);
        await OpenAsync(modal);

        SetParameters(modal, visible: true, deviceId: "dev-B", tagGroupId: null);
        await OpenAsync(modal);

        // A superseded open that FAILS is the same defect wearing the catch block: its diagnostic names
        // a device the operator is no longer looking at, and disables browsing for the one they are.
        deviceAResolve.SetException(new InvalidOperationException("dev-A unreachable"));
        await staleOpen;

        Field<bool>(modal, "_canBrowse").ShouldBeTrue();
        Field<string?>(modal, "_disabledReason").ShouldBeNull();
    }

    /// <inheritdoc/>
    public void Dispose()
    {
        foreach (var renderer in _renderers) { renderer.Dispose(); }
    }

    /// <summary>Builds a modal with its three injected dependencies set and a render handle attached.</summary>
    private RawBrowseModal NewModal(
        IRawTreeService svc, IBrowserSessionService browser, RawTagCsvExportReader exportReader)
    {
        var modal = new RawBrowseModal();
        Inject(modal, "Svc", svc);
        Inject(modal, "BrowserService", browser);
        Inject(modal, "ExportReader", exportReader);

        var renderer = new InertRenderer();
        _renderers.Add(renderer);
        renderer.Attach(modal);

        return modal;
    }

    /// <summary>An export reader over a factory that fails loudly — for tests that must never reach it.</summary>
    private static RawTagCsvExportReader NullExportReader()
        => new(new GatedDbContextFactory(dbName: null, gate: Task.CompletedTask));

    /// <summary>Seeds a lone tag-group row into a fresh InMemory database and returns its name.</summary>
    private static string SeedGroup(string tagGroupId, string deviceId, string name)
    {
        var dbName = $"rawbrowse-{Guid.NewGuid():N}";
        using var db = RawTreeTestDb.CreateNamed(dbName);
        db.TagGroups.Add(new TagGroup { TagGroupId = tagGroupId, DeviceId = deviceId, Name = name });
        db.SaveChanges();
        return dbName;
    }

    /// <summary>
    ///     Sets the modal's <c>[Parameter]</c>s. By reflection because BL0005 forbids assigning component
    ///     parameters from outside the component, and this project treats warnings as errors.
    /// </summary>
    private static void SetParameters(
        RawBrowseModal modal, bool visible, string deviceId, string? tagGroupId)
    {
        Set("Visible", visible);
        Set("DeviceId", deviceId);
        Set("TagGroupId", tagGroupId);

        void Set(string name, object? value)
        {
            var property = typeof(RawBrowseModal).GetProperty(name);
            property.ShouldNotBeNull($"the [Parameter] {name} was renamed or removed.");
            property!.SetValue(modal, value);
        }
    }

    /// <summary>Sets one of the <c>@inject</c>-generated private properties.</summary>
    private static void Inject(RawBrowseModal modal, string name, object value)
    {
        var property = typeof(RawBrowseModal).GetProperty(
            name,
            BindingFlags.NonPublic | BindingFlags.Instance);

        property.ShouldNotBeNull($"the injected {name} property was renamed or removed.");

        property!.SetValue(modal, value);
    }

    /// <summary>Drives the open path — the lifecycle method the resolve hangs off.</summary>
    private static async Task OpenAsync(RawBrowseModal modal)
    {
        var method = typeof(RawBrowseModal).GetMethod(
            "OnParametersSetAsync",
            BindingFlags.NonPublic | BindingFlags.Instance);

        method.ShouldNotBeNull("the open path moved off OnParametersSetAsync — retarget this driver.");

        await (Task)method!.Invoke(modal, null)!;
    }

    /// <summary>Reads one of the modal's private resolve-state fields.</summary>
    private static T Field<T>(RawBrowseModal modal, string name)
    {
        var field = typeof(RawBrowseModal).GetField(name, BindingFlags.NonPublic | BindingFlags.Instance);
        field.ShouldNotBeNull($"the modal's {name} field was renamed or removed.");
        return (T)field!.GetValue(modal)!;
    }

    /// <summary>
    ///     An <see cref="IDbContextFactory{TContext}"/> whose context creation can be held open, so a
    ///     test can suspend a resolve inside <c>ResolveGroupContextAsync</c> and interleave a second open.
    ///     A null database name means "must never be called".
    /// </summary>
    private sealed class GatedDbContextFactory(string? dbName, Task gate)
        : IDbContextFactory<OtOpcUaConfigDbContext>
    {
        /// <inheritdoc/>
        public OtOpcUaConfigDbContext CreateDbContext()
        {
            dbName.ShouldNotBeNull("the group-context resolve was reached by a test that forbids it.");
            return RawTreeTestDb.CreateNamed(dbName!);
        }

        /// <inheritdoc/>
        public async Task<OtOpcUaConfigDbContext> CreateDbContextAsync(CancellationToken ct = default)
        {
            await gate;
            return CreateDbContext();
        }
    }

    /// <summary>
    ///     Browse gate stand-in: every driver+config can browse, so a test asserting that a stale run did
    ///     not disable browsing has a true baseline to be falsified against. Nothing else is reachable —
    ///     these tests never open a session.
    /// </summary>
    private sealed class FakeBrowserSessionService : IBrowserSessionService
    {
        /// <inheritdoc/>
        public bool CanBrowse(string driverType, string configJson) => true;

        /// <inheritdoc/>
        public Task<BrowseOpenResult> OpenAsync(string driverType, string configJson, CancellationToken ct)
            => throw new NotImplementedException();

        /// <inheritdoc/>
        public Task<IReadOnlyList<BrowseNode>> RootAsync(Guid token, CancellationToken ct)
            => throw new NotImplementedException();

        /// <inheritdoc/>
        public Task<IReadOnlyList<BrowseNode>> ExpandAsync(Guid token, string nodeId, CancellationToken ct)
            => throw new NotImplementedException();

        /// <inheritdoc/>
        public Task<IReadOnlyList<AttributeInfo>> AttributesAsync(Guid token, string nodeId, CancellationToken ct)
            => throw new NotImplementedException();

        /// <inheritdoc/>
        public Task<int> RequestRebirthAsync(Guid token, string scope, CancellationToken ct)
            => throw new NotImplementedException();

        /// <inheritdoc/>
        public bool CanRequestRebirth(Guid token) => false;

        /// <inheritdoc/>
        public Task CloseAsync(Guid token) => throw new NotImplementedException();
    }

    /// <summary>
    ///     The smallest renderer that gives a component a working render handle: <c>StateHasChanged</c>
    ///     throws without one, and this modal calls it on the open path. Renders are built and then
    ///     discarded — the tests read the modal's state, not its markup.
    /// </summary>
    private sealed class InertRenderer()
        : Renderer(new ServiceCollection().BuildServiceProvider(), NullLoggerFactory.Instance)
    {
        /// <inheritdoc/>
        public override Dispatcher Dispatcher { get; } = new InlineDispatcher();

        /// <summary>Assigns the component a render handle, as a root component would receive.</summary>
        public void Attach(IComponent component) => AssignRootComponentId(component);

        /// <inheritdoc/>
        protected override void HandleException(Exception exception)
            => ExceptionDispatchInfo.Capture(exception).Throw();

        /// <inheritdoc/>
        protected override Task UpdateDisplayAsync(in RenderBatch renderBatch) => Task.CompletedTask;
    }

    /// <summary>
    ///     Runs everything on the calling thread. The real dispatcher would refuse a
    ///     <c>StateHasChanged</c> raised from a test thread (or from a resolve continuation), which is
    ///     exactly what these tests do.
    /// </summary>
    private sealed class InlineDispatcher : Dispatcher
    {
        /// <inheritdoc/>
        public override bool CheckAccess() => true;

        /// <inheritdoc/>
        public override Task InvokeAsync(Action workItem)
        {
            workItem();
            return Task.CompletedTask;
        }

        /// <inheritdoc/>
        public override Task InvokeAsync(Func<Task> workItem) => workItem();

        /// <inheritdoc/>
        public override Task<TResult> InvokeAsync<TResult>(Func<TResult> workItem)
            => Task.FromResult(workItem());

        /// <inheritdoc/>
        public override Task<TResult> InvokeAsync<TResult>(Func<Task<TResult>> workItem) => workItem();
    }
}