using System.Linq;
using System.Text.Json;
using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
using ZB.MOM.WW.OtOpcUa.Configuration.Enums;
using ZB.MOM.WW.OtOpcUa.OpcUaServer;
using ZB.MOM.WW.OtOpcUa.Runtime.Drivers;

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

/// <summary>
///     Proves the Phase 4c array intent (<c>isArray</c> + optional <c>arrayLength</c>), which rides
///     inside the raw <c>TagConfig</c> JSON blob, round-trips with byte-parity through both
///     equipment-tag producers: the live-edit composer (<see cref="Phase7Composer.Compose"/>) and the
///     artifact decoder (<see cref="DeploymentArtifact.ParseComposition(System.ReadOnlySpan{byte})"/>).
///     A secondary/follower node decoding a serialized deployment artifact MUST materialise array tags
///     identically to the primary, so the artifact side must derive <c>IsArray</c> / <c>ArrayLength</c>
///     from the same blob the composer parses. The composer's <c>ExtractTagArray</c> is internal and not
///     visible to this test assembly (<c>InternalsVisibleTo</c> only names the OpcUaServer.Tests
///     project), so byte-parity is asserted via the public-surface round-trip — exactly as the sibling
///     <see cref="DeploymentArtifactHistorizeParityTests"/> does.
/// </summary>
public sealed class DeploymentArtifactArrayParityTests
{
    /// <summary>
    ///     One draft consumed by both producers, exercising every <c>ExtractTagArray</c> branch:
    ///     <c>isArray:true,arrayLength:16</c> ⇒ <c>(true, 16u)</c>; absent ⇒ <c>(false, null)</c>;
    ///     <c>isArray:true</c> with no length ⇒ <c>(true, null)</c>; a non-number (string) length while
    ///     <c>isArray:true</c> ⇒ <c>(true, null)</c>. The decoded <c>EquipmentTags</c> must equal the
    ///     composer's element-wise (positional-record value equality) and in the same order, proving
    ///     <c>IsArray</c> / <c>ArrayLength</c> are derived byte-identically on both seams.
    /// </summary>
    [Fact]
    public void Composer_and_artifact_agree_on_array_equipment_tags()
    {
        var ns = new Namespace
        {
            NamespaceId = "ns-eq",
            ClusterId = "c1",
            Kind = NamespaceKind.Equipment,
            NamespaceUri = "urn:eq",
        };
        var driver = new DriverInstance
        {
            DriverInstanceId = "drv-modbus",
            ClusterId = "c1",
            NamespaceId = "ns-eq",
            Name = "Modbus1",
            DriverType = "Modbus",
            DriverConfig = "{}",
        };
        var area = new UnsArea { UnsAreaId = "area-1", ClusterId = "c1", Name = "filling" };
        var line = new UnsLine { UnsLineId = "line-1", UnsAreaId = "area-1", Name = "line-1" };
        var equip = new Equipment
        {
            EquipmentId = "eq-1",
            DriverInstanceId = "drv-modbus",
            UnsLineId = "line-1",
            Name = "FillingPump",
            MachineCode = "FILLINGPUMP",
        };

        // Array WITH an explicit bounded length → (true, 16u).
        var arrayBoundedTag = new Tag
        {
            TagId = "tag-array-bounded",
            DriverInstanceId = "drv-modbus",
            EquipmentId = "eq-1",
            FolderPath = null,
            Name = "Recipe",
            DataType = "Int32",
            AccessLevel = TagAccessLevel.Read,
            TagConfig = "{\"FullName\":\"40001\",\"isArray\":true,\"arrayLength\":16}",
        };
        // Plain scalar — no isArray flag → (false, null).
        var scalarTag = new Tag
        {
            TagId = "tag-scalar",
            DriverInstanceId = "drv-modbus",
            EquipmentId = "eq-1",
            FolderPath = null,
            Name = "Speed",
            DataType = "Float",
            AccessLevel = TagAccessLevel.ReadWrite,
            TagConfig = "{\"FullName\":\"40002\"}",
        };
        // Array WITHOUT a length → (true, null) ⇒ unbounded 1-D array at materialisation.
        var arrayUnboundedTag = new Tag
        {
            TagId = "tag-array-unbounded",
            DriverInstanceId = "drv-modbus",
            EquipmentId = "eq-1",
            FolderPath = null,
            Name = "Trace",
            DataType = "Float",
            AccessLevel = TagAccessLevel.Read,
            TagConfig = "{\"FullName\":\"40003\",\"isArray\":true}",
        };
        // Array with a NON-number (string) length token → length ignored ⇒ (true, null). This well-formed
        // blob exercises the artifact-side private ExtractTagArray's number-guard branch through the real
        // round-trip (it can't be unit-tested directly because it's private). A truly malformed TagConfig
        // string would cause ExtractTagFullName to return "" and break the SequenceEqual on other fields,
        // so the throws/malformed path is covered by the composer unit test, not here.
        var arrayBadLengthTag = new Tag
        {
            TagId = "tag-array-badlen",
            DriverInstanceId = "drv-modbus",
            EquipmentId = "eq-1",
            FolderPath = null,
            Name = "Buffer",
            DataType = "Int32",
            AccessLevel = TagAccessLevel.Read,
            TagConfig = "{\"FullName\":\"40004\",\"isArray\":true,\"arrayLength\":\"sixteen\"}",
        };

        var areas = new[] { area };
        var lines = new[] { line };
        var equipment = new[] { equip };
        var drivers = new[] { driver };
        var tags = new[] { arrayBoundedTag, scalarTag, arrayUnboundedTag, arrayBadLengthTag };
        var namespaces = new[] { ns };

        // ---- Side 1: the live-edit composer ----
        var composed = Phase7Composer.Compose(
            areas, lines, equipment, drivers, Array.Empty<ScriptedAlarm>(), tags, namespaces);

        // ---- Side 2: serialise the SAME draft to the artifact blob shape, then decode it ----
        var blob = JsonSerializer.SerializeToUtf8Bytes(new
        {
            Namespaces = new[]
            {
                new { ns.NamespaceId, ns.ClusterId, Kind = (int)ns.Kind },
            },
            DriverInstances = new[]
            {
                new { driver.DriverInstanceId, driver.DriverType, driver.DriverConfig, driver.NamespaceId, driver.ClusterId },
            },
            Tags = new[]
            {
                ToSnapshot(arrayBoundedTag),
                ToSnapshot(scalarTag),
                ToSnapshot(arrayUnboundedTag),
                ToSnapshot(arrayBadLengthTag),
            },
        });

        var decoded = DeploymentArtifact.ParseComposition(blob);

        // ---- Full byte-parity: every field, same order (positional-record value equality) ----
        decoded.EquipmentTags.Count.ShouldBe(4);
        decoded.EquipmentTags.SequenceEqual(composed.EquipmentTags).ShouldBeTrue();

        // Spell out the array fields per-tag so a divergence names the offending tag.
        var arrayBounded = decoded.EquipmentTags.Single(t => t.TagId == "tag-array-bounded");
        arrayBounded.IsArray.ShouldBeTrue();
        arrayBounded.ArrayLength.ShouldBe(16u);
        composed.EquipmentTags.Single(t => t.TagId == "tag-array-bounded").IsArray.ShouldBeTrue();
        composed.EquipmentTags.Single(t => t.TagId == "tag-array-bounded").ArrayLength.ShouldBe(16u);

        var scalar = decoded.EquipmentTags.Single(t => t.TagId == "tag-scalar");
        scalar.IsArray.ShouldBeFalse();
        scalar.ArrayLength.ShouldBeNull();
        composed.EquipmentTags.Single(t => t.TagId == "tag-scalar").IsArray.ShouldBeFalse();
        composed.EquipmentTags.Single(t => t.TagId == "tag-scalar").ArrayLength.ShouldBeNull();

        var arrayUnbounded = decoded.EquipmentTags.Single(t => t.TagId == "tag-array-unbounded");
        arrayUnbounded.IsArray.ShouldBeTrue();
        arrayUnbounded.ArrayLength.ShouldBeNull();
        composed.EquipmentTags.Single(t => t.TagId == "tag-array-unbounded").IsArray.ShouldBeTrue();
        composed.EquipmentTags.Single(t => t.TagId == "tag-array-unbounded").ArrayLength.ShouldBeNull();

        // 4th tag: isArray:true with a string arrayLength ⇒ (true, null) on both sides. Exercises the
        // artifact-side private ExtractTagArray's number-guard branch.
        var arrayBadLength = decoded.EquipmentTags.Single(t => t.TagId == "tag-array-badlen");
        arrayBadLength.IsArray.ShouldBeTrue();
        arrayBadLength.ArrayLength.ShouldBeNull();
        composed.EquipmentTags.Single(t => t.TagId == "tag-array-badlen").IsArray.ShouldBeTrue();
        composed.EquipmentTags.Single(t => t.TagId == "tag-array-badlen").ArrayLength.ShouldBeNull();
    }

    /// <summary>The Pascal-case snapshot a <see cref="Tag"/> EF entity serialises to in the artifact
    /// (matches ConfigComposer); the equipment-tag decoder re-parses these fields — including the raw
    /// <c>TagConfig</c> blob the array flags ride inside.</summary>
    private static object ToSnapshot(Tag t) => new
    {
        t.TagId,
        t.DriverInstanceId,
        t.EquipmentId,
        t.Name,
        t.FolderPath,
        t.DataType,
        AccessLevel = (int)t.AccessLevel,
        t.TagConfig,
    };
}