using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging.Abstractions;
using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
using ZB.MOM.WW.OtOpcUa.OpcUaServer;
using ZB.MOM.WW.OtOpcUa.Runtime;
using ZB.MOM.WW.OtOpcUa.Runtime.Historian;

namespace ZB.MOM.WW.OtOpcUa.Runtime.Tests.Historian;

/// <summary>
///     Verifies the config-gated <c>AddHistorianProvisioning</c> registration AND that a registered
///     provisioner is actually reached by the address-space applier on a historized-tag deploy. This is the
///     wiring the HistorianGateway-integration review found missing: PR #423 shipped
///     <c>GatewayTagProvisioner</c> + unit tests but never registered it in DI nor passed it into the applier,
///     so <c>EnsureTags</c> was dormant (every deploy used the no-op <see cref="NullHistorianProvisioning"/>).
///     <para>
///         When the <c>ServerHistorian</c> section is absent or disabled the <see cref="NullHistorianProvisioning"/>
///         default seeded by <c>AddOtOpcUaRuntime</c> survives (the factory is never invoked); when it is enabled
///         the factory's returned <see cref="IHistorianProvisioning"/> wins (last-registration-wins over the
///         <c>TryAddSingleton</c> Null default) and — constructed into the applier the way
///         <c>WithOtOpcUaRuntimeActors</c> does — its <see cref="IHistorianProvisioning.EnsureTagsAsync"/> fires
///         for an added historized tag.
///     </para>
/// </summary>
public sealed class AddHistorianProvisioningTests
{
    /// <summary>Capturing <see cref="IHistorianProvisioning"/> double — records the requests it was handed and
    /// signals a <see cref="TaskCompletionSource"/> when invoked so the fire-and-forget applier dispatch can be
    /// awaited deterministically.</summary>
    private sealed class CapturingProvisioner : IHistorianProvisioning
    {
        private readonly TaskCompletionSource _called = new(TaskCreationOptions.RunContinuationsAsynchronously);

        /// <summary>The requests the applier handed to <see cref="EnsureTagsAsync"/>.</summary>
        public List<HistorianTagProvisionRequest> Seen { get; } = new();

        /// <summary>Completes once <see cref="EnsureTagsAsync"/> has been invoked.</summary>
        public Task Called => _called.Task;

        /// <inheritdoc />
        public Task<HistorianProvisionResult> EnsureTagsAsync(
            IReadOnlyList<HistorianTagProvisionRequest> requests, CancellationToken ct)
        {
            Seen.AddRange(requests);
            _called.TrySetResult();
            return Task.FromResult(new HistorianProvisionResult(requests.Count, requests.Count, 0, 0));
        }
    }

    private static IConfiguration ConfigFrom(Dictionary<string, string?> values)
        => new ConfigurationBuilder().AddInMemoryCollection(values).Build();

    private static IConfiguration EnabledConfig() => ConfigFrom(new Dictionary<string, string?>
    {
        ["ServerHistorian:Enabled"] = "true",
        ["ServerHistorian:Endpoint"] = "https://historian.example.com:5222",
        ["ServerHistorian:ApiKey"] = "histgw_x_y",
    });

    [Fact]
    public void Section_absent_keeps_null_provisioning_and_factory_not_invoked()
    {
        var factoryInvoked = false;
        var services = new ServiceCollection();
        services.AddOtOpcUaRuntime();

        services.AddHistorianProvisioning(ConfigFrom(new Dictionary<string, string?>()), (_, _) =>
        {
            factoryInvoked = true;
            return new CapturingProvisioner();
        });

        using var provider = services.BuildServiceProvider();
        provider.GetRequiredService<IHistorianProvisioning>().ShouldBeSameAs(NullHistorianProvisioning.Instance);
        factoryInvoked.ShouldBeFalse();
    }

    [Fact]
    public void Section_disabled_keeps_null_provisioning_and_factory_not_invoked()
    {
        var factoryInvoked = false;
        var services = new ServiceCollection();
        services.AddOtOpcUaRuntime();
        var config = ConfigFrom(new Dictionary<string, string?> { ["ServerHistorian:Enabled"] = "false" });

        services.AddHistorianProvisioning(config, (_, _) =>
        {
            factoryInvoked = true;
            return new CapturingProvisioner();
        });

        using var provider = services.BuildServiceProvider();
        provider.GetRequiredService<IHistorianProvisioning>().ShouldBeSameAs(NullHistorianProvisioning.Instance);
        factoryInvoked.ShouldBeFalse();
    }

    [Fact]
    public void Section_enabled_registers_factory_provisioner_over_the_null_default()
    {
        var prov = new CapturingProvisioner();
        var services = new ServiceCollection();
        services.AddOtOpcUaRuntime();

        services.AddHistorianProvisioning(EnabledConfig(), (_, _) => prov);

        using var provider = services.BuildServiceProvider();
        var resolved = provider.GetRequiredService<IHistorianProvisioning>();
        resolved.ShouldBeSameAs(prov);
        resolved.ShouldNotBeSameAs(NullHistorianProvisioning.Instance);
    }

    [Fact]
    public void Section_enabled_passes_bound_options_to_factory()
    {
        ServerHistorianOptions? seen = null;
        var services = new ServiceCollection();
        services.AddOtOpcUaRuntime();
        var config = ConfigFrom(new Dictionary<string, string?>
        {
            ["ServerHistorian:Enabled"] = "true",
            ["ServerHistorian:Endpoint"] = "https://historian.example.com:5222",
            ["ServerHistorian:ApiKey"] = "histgw_x_y",
            ["ServerHistorian:UseTls"] = "true",
            ["ServerHistorian:CaCertificatePath"] = "/etc/ssl/gateway-ca.pem",
        });

        services.AddHistorianProvisioning(config, (opts, _) =>
        {
            seen = opts;
            return new CapturingProvisioner();
        });

        using var provider = services.BuildServiceProvider();
        _ = provider.GetRequiredService<IHistorianProvisioning>();

        seen.ShouldNotBeNull();
        seen.Endpoint.ShouldBe("https://historian.example.com:5222");
        seen.ApiKey.ShouldBe("histgw_x_y");
        seen.UseTls.ShouldBeTrue();
        seen.CaCertificatePath.ShouldBe("/etc/ssl/gateway-ca.pem");
    }

    /// <summary>
    ///     The end-to-end wiring proof the dormant-provisioner bug needed: register the provisioner via
    ///     <c>AddHistorianProvisioning</c>, resolve it, construct the <see cref="AddressSpaceApplier"/> EXACTLY
    ///     as <c>WithOtOpcUaRuntimeActors</c> does (<c>provisioning: resolver.GetService&lt;IHistorianProvisioning&gt;()</c>),
    ///     then apply a plan that adds a historized tag and assert the gateway-backed
    ///     <see cref="IHistorianProvisioning.EnsureTagsAsync"/> actually fires (with the resolved historian name).
    /// </summary>
    [Fact]
    public async Task Registered_provisioner_is_invoked_by_the_applier_on_a_historized_deploy()
    {
        var prov = new CapturingProvisioner();
        var services = new ServiceCollection();
        services.AddOtOpcUaRuntime();
        services.AddHistorianProvisioning(EnabledConfig(), (_, _) => prov);
        using var provider = services.BuildServiceProvider();

        // Mirror the production construction in WithOtOpcUaRuntimeActors: resolve the provisioner and pass it in.
        var resolved = provider.GetService<IHistorianProvisioning>();
        var applier = new AddressSpaceApplier(
            NullOpcUaAddressSpaceSink.Instance, NullLogger<AddressSpaceApplier>.Instance, provisioning: resolved);

        applier.Apply(PlanWithAddedTags(
            HistorizedTag(displayName: "Temp", historianName: "Pump1.Temp", dataType: "Float32"),
            NonHistorizedTag(displayName: "Run", dataType: "Boolean")));

        await prov.Called.WaitAsync(TimeSpan.FromSeconds(5));
        prov.Seen.Count.ShouldBe(1);
        prov.Seen[0].TagName.ShouldBe("Pump1.Temp");
        prov.Seen[0].DataType.ShouldBe(DriverDataType.Float32);
    }

    private static EquipmentTagPlan HistorizedTag(string displayName, string? historianName, string dataType, string fullName = "ref")
        => new("tag-" + displayName, "eq-1", "drv", FolderPath: "", Name: displayName, DataType: dataType, FullName: fullName,
            Writable: false, Alarm: null, IsHistorized: true, HistorianTagname: historianName);

    private static EquipmentTagPlan NonHistorizedTag(string displayName, string dataType)
        => new("tag-" + displayName, "eq-1", "drv", FolderPath: "", Name: displayName, DataType: dataType, FullName: "ref",
            Writable: false, Alarm: null, IsHistorized: false, HistorianTagname: null);

    private static AddressSpacePlan PlanWithAddedTags(params EquipmentTagPlan[] tags) => new(
        AddedEquipment: Array.Empty<EquipmentNode>(),
        RemovedEquipment: Array.Empty<EquipmentNode>(),
        ChangedEquipment: Array.Empty<AddressSpacePlan.EquipmentDelta>(),
        AddedDrivers: Array.Empty<DriverInstancePlan>(),
        RemovedDrivers: Array.Empty<DriverInstancePlan>(),
        ChangedDrivers: Array.Empty<AddressSpacePlan.DriverDelta>(),
        AddedAlarms: Array.Empty<ScriptedAlarmPlan>(),
        RemovedAlarms: Array.Empty<ScriptedAlarmPlan>(),
        ChangedAlarms: Array.Empty<AddressSpacePlan.AlarmDelta>())
    {
        AddedEquipmentTags = tags,
    };
}