using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;

namespace ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests;

/// <summary>
///     v3 Batch 4 (B4-WP1) — the classifier folds the Raw + UNS subtree diff sets into its routing policy:
///     raw/uns adds count as adds (PureAdd), removes as removes (PureRemove).
///     <para>Surgical deploys (2026-08-15 Task 4) narrowed the Changed sets: a NON-alarm raw-tag delta whose
///     only differences are the in-place-updatable attributes and/or its <c>ReferencingEquipmentPaths</c> is
///     surgical (NOT a rebuild), and every UNS-reference delta is applied remove+recreate. Alarm-bearing and
///     identity-field raw-tag deltas still route to Rebuild — the default-closed WP4 notifier guard.</para>
/// </summary>
public sealed class AddressSpaceChangeClassifierDualNamespaceTests
{
    private static readonly RawContainerNode Folder = new("Plant", null, "Plant", RawNodeKind.Folder);

    private static RawTagPlan RawTag(string nodeId) =>
        new("t-1", nodeId, "Plant/Modbus1/PLC-A", "drv-1", "Speed", "Float",
            Writable: false, Alarm: null, ReferencingEquipmentPaths: Array.Empty<string>());

    private static UnsReferenceVariable UnsRef(string nodeId) =>
        new("ref-1", "eq-1", nodeId, "Speed", "Plant/Modbus1/PLC-A/Speed", "Float", Writable: false);

    private static AddressSpacePlan Empty() => new(
        Array.Empty<EquipmentNode>(), Array.Empty<EquipmentNode>(), Array.Empty<AddressSpacePlan.EquipmentDelta>(),
        Array.Empty<DriverInstancePlan>(), Array.Empty<DriverInstancePlan>(), Array.Empty<AddressSpacePlan.DriverDelta>(),
        Array.Empty<ScriptedAlarmPlan>(), Array.Empty<ScriptedAlarmPlan>(), Array.Empty<AddressSpacePlan.AlarmDelta>());

    [Fact]
    public void Added_raw_tag_only_is_PureAdd()
    {
        var plan = Empty() with { AddedRawTags = new[] { RawTag("Plant/Modbus1/PLC-A/Speed") } };
        AddressSpaceChangeClassifier.Classify(plan).ShouldBe(AddressSpaceChangeKind.PureAdd);
    }

    [Fact]
    public void Added_raw_container_only_is_PureAdd()
    {
        var plan = Empty() with { AddedRawContainers = new[] { Folder } };
        AddressSpaceChangeClassifier.Classify(plan).ShouldBe(AddressSpaceChangeKind.PureAdd);
    }

    [Fact]
    public void Added_uns_reference_only_is_PureAdd()
    {
        var plan = Empty() with { AddedUnsReferenceVariables = new[] { UnsRef("filling/line-1/station-1/Speed") } };
        AddressSpaceChangeClassifier.Classify(plan).ShouldBe(AddressSpaceChangeKind.PureAdd);
    }

    [Fact]
    public void Removed_raw_tag_only_is_PureRemove()
    {
        var plan = Empty() with { RemovedRawTags = new[] { RawTag("Plant/Modbus1/PLC-A/Speed") } };
        AddressSpaceChangeClassifier.Classify(plan).ShouldBe(AddressSpaceChangeKind.PureRemove);
    }

    [Fact]
    public void Removed_uns_reference_only_is_PureRemove()
    {
        var plan = Empty() with { RemovedUnsReferenceVariables = new[] { UnsRef("filling/line-1/station-1/Speed") } };
        AddressSpaceChangeClassifier.Classify(plan).ShouldBe(AddressSpaceChangeKind.PureRemove);
    }

    [Fact]
    public void Raw_rename_add_and_remove_is_AddRemoveMix()
    {
        var plan = Empty() with
        {
            RemovedRawTags = new[] { RawTag("Plant/Modbus1/PLC-A/Speed") },
            AddedRawTags = new[] { RawTag("Plant/Modbus1/PLC-A/Velocity") },
        };
        AddressSpaceChangeClassifier.Classify(plan).ShouldBe(AddressSpaceChangeKind.AddRemoveMix);
    }

    /// <summary>The headline surgical case: adding/dropping a <c>UnsTagReference</c> flips the BACKING raw tag
    /// to Changed (ReferencingEquipmentPaths is part of RawTagPlan's equality). For a non-alarm VALUE tag that
    /// set is node-inert — it only drives native-alarm notifier wiring — so it must NOT tear down the world.
    /// (Was <c>Changed_raw_tag_is_Rebuild</c>; deliberately re-pointed by 2026-08-15 Task 4.)</summary>
    [Fact]
    public void Reference_only_raw_tag_delta_is_not_a_rebuild()
    {
        var plan = Empty() with
        {
            ChangedRawTags = new[]
            {
                new AddressSpacePlan.RawTagDelta(
                    RawTag("Plant/Modbus1/PLC-A/Speed"),
                    RawTag("Plant/Modbus1/PLC-A/Speed") with
                    {
                        ReferencingEquipmentPaths = new[] { "filling/line-1/station-1" },
                    }),
            },
        };
        AddressSpaceChangeClassifier.Classify(plan).ShouldBe(AddressSpaceChangeKind.AttributeOnly);
    }

    /// <summary>The in-place-updatable attribute whitelist (Writable / IsHistorized / HistorianTagname /
    /// DataType / IsArray / ArrayLength) on a non-alarm raw tag is surgical, not a rebuild.</summary>
    [Theory]
    [InlineData("writable")]
    [InlineData("historized")]
    [InlineData("historianTagname")]
    [InlineData("dataType")]
    [InlineData("array")]
    [InlineData("arrayLength")]
    public void Attribute_raw_tag_delta_is_not_a_rebuild(string field)
    {
        var baseline = RawTag("Plant/Modbus1/PLC-A/Speed");
        // ArrayLength moving ALONE (a resize of an already-array tag) — the whitelist must carry ArrayLength
        // in its own right, not only as a passenger of an IsArray flip. Its "previous" is already an array.
        var prev = field == "arrayLength" ? baseline with { IsArray = true, ArrayLength = 8 } : baseline;
        var cur = field switch
        {
            "writable" => prev with { Writable = true },
            "historized" => prev with { IsHistorized = true },
            "historianTagname" => prev with { IsHistorized = true, HistorianTagname = "Plant.PLC_A.Speed" },
            "dataType" => prev with { DataType = "Double" },
            "array" => prev with { IsArray = true, ArrayLength = 8 },
            "arrayLength" => prev with { ArrayLength = 16 },
            _ => throw new ArgumentOutOfRangeException(nameof(field)),
        };

        var plan = Empty() with { ChangedRawTags = new[] { new AddressSpacePlan.RawTagDelta(prev, cur) } };
        AddressSpaceChangeClassifier.Classify(plan).ShouldBe(AddressSpaceChangeKind.AttributeOnly);
    }

    /// <summary>WP4 binding guard: a raw tag carrying a native alarm on EITHER side still rebuilds — the
    /// rebuild is what clears + re-wires the per-equipment alarm notifiers.</summary>
    [Theory]
    [InlineData(true, false)]
    [InlineData(false, true)]
    [InlineData(true, true)]
    public void Alarm_bearing_raw_tag_delta_still_rebuilds(bool alarmBefore, bool alarmAfter)
    {
        var alarm = new EquipmentTagAlarmInfo("OffNormalAlarm", 700);
        var prev = RawTag("Plant/Modbus1/PLC-A/Speed") with { Alarm = alarmBefore ? alarm : null };
        var cur = RawTag("Plant/Modbus1/PLC-A/Speed") with
        {
            Alarm = alarmAfter ? alarm : null,
            ReferencingEquipmentPaths = new[] { "filling/line-1/station-1" },
        };

        var plan = Empty() with { ChangedRawTags = new[] { new AddressSpacePlan.RawTagDelta(prev, cur) } };
        AddressSpaceChangeClassifier.Classify(plan).ShouldBe(AddressSpaceChangeKind.Rebuild);
    }

    /// <summary>WP4 binding guard, CONTENT edition: an alarm present on BOTH sides whose severity (or type)
    /// moved still rebuilds. The null-check pair alone does not decide it — the with-equality whitelist has to
    /// leave <c>Alarm</c> out, so the two <see cref="EquipmentTagAlarmInfo"/> values compare unequal.</summary>
    [Fact]
    public void Alarm_content_only_raw_tag_delta_still_rebuilds()
    {
        var prev = RawTag("Plant/Modbus1/PLC-A/Speed") with { Alarm = new EquipmentTagAlarmInfo("OffNormalAlarm", 500) };
        var cur = prev with { Alarm = new EquipmentTagAlarmInfo("OffNormalAlarm", 900) };

        var plan = Empty() with { ChangedRawTags = new[] { new AddressSpacePlan.RawTagDelta(prev, cur) } };
        AddressSpaceChangeClassifier.Classify(plan).ShouldBe(AddressSpaceChangeKind.Rebuild);
    }

    /// <summary>The QUANTIFIER: the rebuild gate is <c>.Any(d =&gt; !eligible(d))</c>, so ONE ineligible raw-tag
    /// delta must rebuild even when every other delta in the same plan is surgical. Pins against a regression
    /// to <c>.All(eligible)</c> on the wrong side, or to inspecting only <c>First()</c> — either of which would
    /// apply an identity/alarm change as an in-place attribute update and leave the node mis-wired.</summary>
    [Fact]
    public void One_ineligible_raw_tag_delta_among_eligible_ones_still_rebuilds()
    {
        var eligiblePrev = RawTag("Plant/Modbus1/PLC-A/Speed");
        var ineligiblePrev = RawTag("Plant/Modbus1/PLC-A/Temp") with { TagId = "t-2" };

        var plan = Empty() with
        {
            ChangedRawTags = new[]
            {
                // Surgical: a plain historize toggle. Listed FIRST so a First()-only check would pass it.
                new AddressSpacePlan.RawTagDelta(eligiblePrev, eligiblePrev with { IsHistorized = true }),
                // Ineligible: DriverInstanceId re-routes the node to a different driver point.
                new AddressSpacePlan.RawTagDelta(ineligiblePrev, ineligiblePrev with { DriverInstanceId = "drv-2" }),
            },
        };
        AddressSpaceChangeClassifier.Classify(plan).ShouldBe(AddressSpaceChangeKind.Rebuild);
    }

    /// <summary>Default-closed: an identity field outside the whitelist (DriverInstanceId re-routes the node to
    /// another driver point; Name/TagId/ParentNodeId re-shape identity) still forces a full rebuild.</summary>
    [Theory]
    [InlineData("driver")]
    [InlineData("name")]
    [InlineData("tagId")]
    [InlineData("parent")]
    public void Identity_field_raw_tag_delta_still_rebuilds(string field)
    {
        var prev = RawTag("Plant/Modbus1/PLC-A/Speed");
        var cur = field switch
        {
            "driver" => prev with { DriverInstanceId = "drv-2" },
            "name" => prev with { Name = "Velocity" },
            "tagId" => prev with { TagId = "t-2" },
            "parent" => prev with { ParentNodeId = "Plant/Modbus1/PLC-B" },
            _ => throw new ArgumentOutOfRangeException(nameof(field)),
        };

        var plan = Empty() with { ChangedRawTags = new[] { new AddressSpacePlan.RawTagDelta(prev, cur) } };
        AddressSpaceChangeClassifier.Classify(plan).ShouldBe(AddressSpaceChangeKind.Rebuild);
    }

    /// <summary>A UNS-reference re-point (BackingRawPath moved) is applied surgically (remove-previous +
    /// recreate-current), NOT as a rebuild. (Was <c>Uns_reference_repoint_is_Rebuild</c>; deliberately
    /// re-pointed by 2026-08-15 Task 4.)</summary>
    [Fact]
    public void Uns_reference_repoint_delta_is_not_a_rebuild()
    {
        var plan = Empty() with
        {
            ChangedUnsReferenceVariables = new[]
            {
                new AddressSpacePlan.UnsReferenceDelta(
                    UnsRef("filling/line-1/station-1/Speed"),
                    UnsRef("filling/line-1/station-1/Speed") with { BackingRawPath = "Plant/Modbus1/PLC-A/Velocity" }),
            },
        };
        AddressSpaceChangeClassifier.Classify(plan).ShouldBe(AddressSpaceChangeKind.AttributeOnly);
    }

    /// <summary>The other UnsReferenceDelta variant — a display-name override edit keeps the row id while the
    /// NodeId + EffectiveName change. Also surgical (remove-previous + recreate-current).</summary>
    [Fact]
    public void Uns_reference_display_name_delta_is_not_a_rebuild()
    {
        var plan = Empty() with
        {
            ChangedUnsReferenceVariables = new[]
            {
                new AddressSpacePlan.UnsReferenceDelta(
                    UnsRef("filling/line-1/station-1/Speed"),
                    UnsRef("filling/line-1/station-1/LineSpeed") with { EffectiveName = "LineSpeed" }),
            },
        };
        AddressSpaceChangeClassifier.Classify(plan).ShouldBe(AddressSpaceChangeKind.AttributeOnly);
    }

    /// <summary>The headline end-to-end shape: adding ONE UNS reference produces an added UNS variable PLUS the
    /// induced reference-only delta on the backing raw tag. That must classify PureAdd — one node created,
    /// zero teardown, every client subscription server-wide survives.</summary>
    [Fact]
    public void Uns_reference_add_with_induced_reference_only_raw_delta_is_pure_add()
    {
        var prev = RawTag("Plant/Modbus1/PLC-A/Speed");
        var cur = prev with { ReferencingEquipmentPaths = new[] { "filling/line-1/station-1" } };

        var plan = Empty() with
        {
            AddedUnsReferenceVariables = new[] { UnsRef("filling/line-1/station-1/Speed") },
            ChangedRawTags = new[] { new AddressSpacePlan.RawTagDelta(prev, cur) },
        };
        AddressSpaceChangeClassifier.Classify(plan).ShouldBe(AddressSpaceChangeKind.PureAdd);
    }
}