using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
using ZB.MOM.WW.OtOpcUa.Configuration.Enums;
using ZB.MOM.WW.OtOpcUa.Configuration.Validation;

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

/// <summary>
///     v3 WP1: the namespace-binding + Galaxy-FullName rules are retired (Namespace entity gone;
///     Tags are raw-only, not equipment-bound). The retained rules (UNS segments, path length,
///     EquipmentUuid immutability, external-id reservation preflight, EquipmentId derivation,
///     cluster topology, VirtualTag equipment-signal collision) are exercised below against the v3
///     entity shapes. WP4 (Wave C) adds the new v3 rules (raw-name charset, historized-tagname length,
///     UNS effective-leaf uniqueness).
/// </summary>
[Trait("Category", "Unit")]
public sealed class DraftValidatorTests
{
    /// <summary>Verifies that UnsSegment validation rejects uppercase and special characters.</summary>
    /// <param name="name">The segment name to validate.</param>
    /// <param name="shouldPass">Whether the validation should pass for this name.</param>
    [Theory]
    [InlineData("valid-name", true)]
    [InlineData("line-01", true)]
    [InlineData("_default", true)]
    [InlineData("UPPER", false)]
    [InlineData("with space", false)]
    [InlineData("", false)]
    public void UnsSegment_rule_accepts_lowercase_or_default_only(string name, bool shouldPass)
    {
        var uuid = Guid.NewGuid();
        var draft = new DraftSnapshot
        {
            GenerationId = 1, ClusterId = "c",
            Equipment =
            [
                new Equipment
                {
                    EquipmentUuid = uuid,
                    EquipmentId = DraftValidator.DeriveEquipmentId(uuid),
                    Name = name,
                    UnsLineId = "line-a",
                    MachineCode = "m",
                },
            ],
        };

        var errors = DraftValidator.Validate(draft);
        var hasUnsError = errors.Any(e => e.Code == "UnsSegmentInvalid");
        hasUnsError.ShouldBe(!shouldPass);
    }

    /// <summary>Verifies that equipment UUID must remain immutable across generations.</summary>
    [Fact]
    public void EquipmentUuid_change_across_generations_is_rejected()
    {
        var oldUuid = Guid.Parse("11111111-1111-1111-1111-111111111111");
        var newUuid = Guid.Parse("22222222-2222-2222-2222-222222222222");
        var eid = DraftValidator.DeriveEquipmentId(oldUuid);

        var draft = new DraftSnapshot
        {
            GenerationId = 2, ClusterId = "c",
            Equipment = [new Equipment { EquipmentUuid = newUuid, EquipmentId = eid, Name = "eq", UnsLineId = "line-a", MachineCode = "m" }],
            PriorEquipment = [new Equipment { EquipmentUuid = oldUuid, EquipmentId = eid, Name = "eq", UnsLineId = "line-a", MachineCode = "m" }],
        };

        DraftValidator.Validate(draft).ShouldContain(e => e.Code == "EquipmentUuidImmutable");
    }

    /// <summary>Verifies that a ZTag cannot be reserved by a different equipment UUID.</summary>
    [Fact]
    public void ZTag_reserved_by_different_uuid_is_rejected()
    {
        var uuid = Guid.NewGuid();
        var otherUuid = Guid.NewGuid();

        var draft = new DraftSnapshot
        {
            GenerationId = 1, ClusterId = "c",
            Equipment = [new Equipment { EquipmentUuid = uuid, EquipmentId = DraftValidator.DeriveEquipmentId(uuid), Name = "eq", UnsLineId = "line-a", MachineCode = "m", ZTag = "ZT-001" }],
            ActiveReservations = [new ExternalIdReservation { Kind = ReservationKind.ZTag, Value = "ZT-001", EquipmentUuid = otherUuid, ClusterId = "c", FirstPublishedBy = "t" }],
        };

        DraftValidator.Validate(draft).ShouldContain(e => e.Code == "BadDuplicateExternalIdentifier");
    }

    /// <summary>Verifies that equipment ID must be derived from its UUID.</summary>
    [Fact]
    public void EquipmentId_that_does_not_match_derivation_is_rejected()
    {
        var uuid = Guid.NewGuid();
        var draft = new DraftSnapshot
        {
            GenerationId = 1, ClusterId = "c",
            Equipment = [new Equipment { EquipmentUuid = uuid, EquipmentId = "EQ-operator-typed", Name = "eq", UnsLineId = "line-a", MachineCode = "m" }],
        };

        DraftValidator.Validate(draft).ShouldContain(e => e.Code == "EquipmentIdNotDerived");
    }

    /// <summary>Verifies that all violations are reported simultaneously (single-pass validation).</summary>
    [Fact]
    public void Draft_with_multiple_violations_surfaces_all_of_them()
    {
        var uuid = Guid.NewGuid();
        var draft = new DraftSnapshot
        {
            GenerationId = 1, ClusterId = "c",
            // EQ-wrong is not the canonical derivation, and "BAD NAME" fails the UNS segment regex.
            Equipment = [new Equipment { EquipmentUuid = uuid, EquipmentId = "EQ-wrong", Name = "BAD NAME", UnsLineId = "line-a", MachineCode = "m" }],
        };

        var errors = DraftValidator.Validate(draft);
        errors.ShouldContain(e => e.Code == "EquipmentIdNotDerived");
        errors.ShouldContain(e => e.Code == "UnsSegmentInvalid");
    }

    /// <summary>Probe for the deploy-path gate: a full, realistic v3 config (UNS area/line +
    /// canonical Equipment + distinct-named VirtualTags) must produce ZERO validation errors so the
    /// reject-on-any-error deploy gate is safe to activate.</summary>
    [Fact]
    public void Full_realistic_config_passes_all_rules()
    {
        var area = new UnsArea { UnsAreaId = "area-filling", ClusterId = "MAIN", Name = "filling" };
        var line = new UnsLine { UnsLineId = "line-1", UnsAreaId = area.UnsAreaId, Name = "line-1" };

        var rinserUuid = Guid.NewGuid();
        var fillerUuid = Guid.NewGuid();
        var rinser = new Equipment
        {
            EquipmentUuid = rinserUuid,
            EquipmentId = DraftValidator.DeriveEquipmentId(rinserUuid),
            Name = "rinser-01",
            UnsLineId = line.UnsLineId,
            MachineCode = "machine_001",
        };
        var filler = new Equipment
        {
            EquipmentUuid = fillerUuid,
            EquipmentId = DraftValidator.DeriveEquipmentId(fillerUuid),
            Name = "filler-02",
            UnsLineId = line.UnsLineId,
            MachineCode = "machine_002",
        };

        var draft = new DraftSnapshot
        {
            GenerationId = 0,
            ClusterId = string.Empty,        // global snapshot — matches DraftSnapshotFactory.FromConfigDbAsync
            UnsAreas = [area],
            UnsLines = [line],
            Equipment = [rinser, filler],
            VirtualTags =
            [
                BuildVirtualTag(equipmentId: rinser.EquipmentId, name: "oee"),
                BuildVirtualTag(equipmentId: filler.EquipmentId, name: "throughput"),
            ],
        };

        var errors = DraftValidator.Validate(draft);

        errors.ShouldBeEmpty(
            "a realistic canonical deployed config must pass every DraftValidator rule so the " +
            "reject-on-any-error deploy gate is safe; firing rules: " +
            string.Join("; ", errors.Select(e => $"[{e.Code}] {e.Message}")));
    }

    // ------------------------------------------------------------------------------------
    // ValidateNoEquipmentSignalNameCollision — v3: VirtualTag name uniqueness within equipment
    // ------------------------------------------------------------------------------------

    /// <summary>Two VirtualTags sharing (EquipmentId, Name) collide on a single OPC UA NodeId.</summary>
    [Fact]
    public void Two_VirtualTags_same_equipment_and_name_collide()
    {
        var draft = new DraftSnapshot
        {
            GenerationId = 1, ClusterId = "c",
            VirtualTags =
            [
                BuildVirtualTag(equipmentId: "eq-1", name: "speed", suffix: "a"),
                BuildVirtualTag(equipmentId: "eq-1", name: "speed", suffix: "b"),
            ],
        };

        DraftValidator.Validate(draft).ShouldContain(e => e.Code == "EquipmentSignalNameCollision");
    }

    /// <summary>VirtualTags with the same name under DIFFERENT equipment do not collide.</summary>
    [Fact]
    public void Same_name_different_equipment_does_not_collide()
    {
        var draft = new DraftSnapshot
        {
            GenerationId = 1, ClusterId = "c",
            VirtualTags =
            [
                BuildVirtualTag(equipmentId: "eq-1", name: "speed"),
                BuildVirtualTag(equipmentId: "eq-2", name: "speed"),
            ],
        };

        DraftValidator.Validate(draft).ShouldNotContain(e => e.Code == "EquipmentSignalNameCollision");
    }

    private static VirtualTag BuildVirtualTag(string equipmentId, string name, string suffix = "") => new()
    {
        VirtualTagId = $"vtag-{equipmentId}-{name}{suffix}",
        EquipmentId = equipmentId,
        Name = name,
        DataType = "Float",
        ScriptId = "s-1",
    };

    // ------------------------------------------------------------------------------------
    // Phase 6.3 task #148 part 2 — ValidateClusterTopology (unchanged in v3)
    // ------------------------------------------------------------------------------------

    /// <summary>Verifies that cluster topology validation checks node count against declared redundancy mode.</summary>
    /// <param name="nodeCount">The declared cluster node count.</param>
    /// <param name="mode">The declared redundancy mode.</param>
    /// <param name="enabledNodes">The number of enabled nodes to include in the topology.</param>
    /// <param name="expectedDeclaredErrors">The number of ClusterRedundancyModeInvalid errors expected.</param>
    [Theory]
    [InlineData(1, RedundancyMode.None, 1, 0)]  // single-node standalone — ok
    [InlineData(2, RedundancyMode.Warm, 2, 0)]  // 2-node warm — ok
    [InlineData(2, RedundancyMode.Hot,  2, 0)]  // 2-node hot — ok
    [InlineData(1, RedundancyMode.Warm, 1, 1)]  // declared mismatch — should flag
    [InlineData(2, RedundancyMode.None, 2, 1)]  // None with 2 nodes — should flag
    public void ValidateClusterTopology_checks_declared_pair(
        byte nodeCount, RedundancyMode mode, int enabledNodes, int expectedDeclaredErrors)
    {
        var cluster = BuildCluster(nodeCount: nodeCount, mode: mode);
        var nodes = Enumerable.Range(0, enabledNodes)
            .Select(i => BuildNode($"n-{i}", enabled: true))
            .ToList();

        var errors = DraftValidator.ValidateClusterTopology(cluster, nodes);
        errors.Count(e => e.Code == "ClusterRedundancyModeInvalid").ShouldBe(expectedDeclaredErrors);
    }

    /// <summary>Verifies that disabled nodes cause topology validation to fail.</summary>
    [Fact]
    public void ValidateClusterTopology_flags_disabled_node_mismatch()
    {
        var cluster = BuildCluster(nodeCount: 2, mode: RedundancyMode.Hot);
        var nodes = new[]
        {
            BuildNode("primary", enabled: true),
            BuildNode("backup",  enabled: false),
        };

        var errors = DraftValidator.ValidateClusterTopology(cluster, nodes);
        errors.ShouldContain(e => e.Code == "ClusterEnabledNodeCountMismatch");
    }

    /// <summary>Verifies that a valid standalone cluster passes validation.</summary>
    [Fact]
    public void ValidateClusterTopology_returns_no_errors_on_valid_standalone()
    {
        var cluster = BuildCluster(nodeCount: 1, mode: RedundancyMode.None);
        var nodes = new[] { BuildNode("only", enabled: true) };

        var errors = DraftValidator.ValidateClusterTopology(cluster, nodes);
        errors.ShouldBeEmpty();
    }

    private static ServerCluster BuildCluster(byte nodeCount, RedundancyMode mode) => new()
    {
        ClusterId = "c-test",
        Name = "Test",
        Enterprise = "zb",
        Site = "dev",
        NodeCount = nodeCount,
        RedundancyMode = mode,
        Enabled = true,
        CreatedBy = "t",
    };

    private static ClusterNode BuildNode(string id, bool enabled) => new()
    {
        NodeId = id,
        ClusterId = "c-test",
        Host = "localhost",
        OpcUaPort = 4840,
        DashboardPort = 5001,
        ApplicationUri = $"urn:{id}",
        ServiceLevelBase = 200,
        Enabled = enabled,
        CreatedBy = "t",
    };

    // ------------------------------------------------------------------------------------
    // ValidatePathLength — Enterprise/Site length precision (Configuration-003)
    // ------------------------------------------------------------------------------------

    /// <summary>Verifies that path length validation uses actual Enterprise and Site lengths.</summary>
    [Fact]
    public void PathLength_uses_actual_Enterprise_Site_when_provided()
    {
        var areaId = "area-a";
        var lineId = "line-b";
        var uuid = Guid.NewGuid();
        var eqName = new string('x', 90); // 90 chars — exceeds UNS regex but that's a separate error

        var snapshot = new DraftSnapshot
        {
            GenerationId = 1,
            ClusterId = "c",
            Enterprise = "zb",  // 2 chars (actual)
            Site = "s",         // 1 char (actual)
            UnsAreas = [new UnsArea { UnsAreaId = areaId, ClusterId = "c", Name = new string('a', 32) }],
            UnsLines = [new UnsLine { UnsLineId = lineId, UnsAreaId = areaId, Name = new string('b', 32) }],
            Equipment =
            [
                new Equipment
                {
                    EquipmentUuid = uuid,
                    EquipmentId   = DraftValidator.DeriveEquipmentId(uuid),
                    Name          = eqName,
                    UnsLineId     = lineId,
                    MachineCode   = "m",
                },
            ],
        };

        var errors = DraftValidator.Validate(snapshot);

        errors.ShouldNotContain(e => e.Code == "PathTooLong",
            "actual Enterprise='zb' + Site='s' keeps total path at 161 chars — under the 200-char limit");
    }

    /// <summary>Verifies that path length validation uses conservative fallback when Enterprise and Site are absent.</summary>
    [Fact]
    public void PathLength_conservative_fallback_when_Enterprise_Site_absent()
    {
        var areaId = "area-x";
        var lineId = "line-y";
        var uuid = Guid.NewGuid();

        var snapshot = new DraftSnapshot
        {
            GenerationId = 1,
            ClusterId = "c",
            UnsAreas = [new UnsArea { UnsAreaId = areaId, ClusterId = "c", Name = new string('a', 32) }],
            UnsLines = [new UnsLine { UnsLineId = lineId, UnsAreaId = areaId, Name = new string('b', 32) }],
            Equipment =
            [
                new Equipment
                {
                    EquipmentUuid = uuid,
                    EquipmentId   = DraftValidator.DeriveEquipmentId(uuid),
                    Name          = new string('c', 29),
                    UnsLineId     = lineId,
                    MachineCode   = "m",
                },
            ],
        };

        var errors = DraftValidator.Validate(snapshot);

        errors.ShouldNotContain(e => e.Code == "PathTooLong",
            "conservative 32+32+32+32+29+4 = 161 chars is still under the 200-char limit");
    }
}