using Microsoft.EntityFrameworkCore;
using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.AdminUI.Uns;
using ZB.MOM.WW.OtOpcUa.Configuration;
using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
using ZB.MOM.WW.OtOpcUa.Configuration.Enums;

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

/// <summary>
/// Verifies the v3 Batch-3 UNS reference-only equipment mutations on <see cref="UnsTreeService"/>:
/// adding references (with computed RawPath + inherited datatype/access), removing them, setting the
/// display-name override, the cross-cluster rejection, the same-tag / same-name duplicate rejections,
/// and the <see cref="IEffectiveNameGuard"/>-consumed collision rejection (via a configurable fake).
/// </summary>
/// <remarks>
/// The EF InMemory provider enforces neither <c>RowVersion</c> concurrency nor the filtered-unique
/// indexes, so the service's own pre-checks are what protect the data in these tests.
/// </remarks>
[Trait("Category", "Unit")]
public sealed class UnsTreeServiceReferenceTests
{
    private const string EquipmentId = "EQ-1";

    /// <summary>A configurable <see cref="IEffectiveNameGuard"/>: returns <see cref="Result"/> from every check.</summary>
    private sealed class FakeGuard : IEffectiveNameGuard
    {
        public string? Result { get; set; }

        public string? LastProposedName { get; private set; }

        public Task<string?> CheckAsync(
            string equipmentId, string proposedEffectiveName, EffectiveNameSourceKind kind,
            string? excludeSourceId, CancellationToken ct = default)
        {
            LastProposedName = proposedEffectiveName;
            return Task.FromResult(Result);
        }
    }

    private static OtOpcUaConfigDbContext Db(string name) =>
        new(new DbContextOptionsBuilder<OtOpcUaConfigDbContext>().UseInMemoryDatabase(name).Options);

    private static IDbContextFactory<OtOpcUaConfigDbContext> Factory(string name) => UnsTreeTestDb.Factory(name);

    /// <summary>
    /// Seeds two clusters (MAIN, SITE-A), each with driver→device→tags, plus an equipment (<c>EQ-1</c>)
    /// under MAIN. MAIN tags: <c>MAIN/dev1/speed</c> (Float, Read) and <c>MAIN/dev1/running</c>
    /// (Boolean, ReadWrite), with <c>speed</c> also nested under a group <c>grp</c> variant. SITE-A tag:
    /// <c>OTHER/dev2/temp</c> (for the cross-cluster rejection).
    /// </summary>
    private static void Seed(string name)
    {
        using var db = Db(name);

        db.ServerClusters.Add(new ServerCluster { ClusterId = "MAIN", Name = "Main", Enterprise = "zb", Site = "s1", RedundancyMode = RedundancyMode.None, CreatedBy = "t" });
        db.ServerClusters.Add(new ServerCluster { ClusterId = "SITE-A", Name = "Site A", Enterprise = "zb", Site = "s2", RedundancyMode = RedundancyMode.None, CreatedBy = "t" });

        db.UnsAreas.Add(new UnsArea { UnsAreaId = "AREA-1", ClusterId = "MAIN", Name = "assembly" });
        db.UnsLines.Add(new UnsLine { UnsLineId = "LINE-1", UnsAreaId = "AREA-1", Name = "line-a" });
        db.Equipment.Add(new Equipment { EquipmentId = EquipmentId, EquipmentUuid = Guid.NewGuid(), UnsLineId = "LINE-1", Name = "machine-1", MachineCode = "mc_1" });

        // MAIN raw topology.
        db.DriverInstances.Add(new DriverInstance { DriverInstanceId = "DRV-1", ClusterId = "MAIN", Name = "MAIN", DriverType = "Modbus", DriverConfig = "{}" });
        db.Devices.Add(new Device { DeviceId = "DEV-1", DriverInstanceId = "DRV-1", Name = "dev1", DeviceConfig = "{}" });
        db.TagGroups.Add(new TagGroup { TagGroupId = "TG-1", DeviceId = "DEV-1", Name = "grp" });
        db.Tags.Add(new Tag { TagId = "TAG-speed", DeviceId = "DEV-1", Name = "speed", DataType = "Float", AccessLevel = TagAccessLevel.Read, TagConfig = "{}" });
        db.Tags.Add(new Tag { TagId = "TAG-running", DeviceId = "DEV-1", Name = "running", DataType = "Boolean", AccessLevel = TagAccessLevel.ReadWrite, TagConfig = "{}" });
        db.Tags.Add(new Tag { TagId = "TAG-grouped", DeviceId = "DEV-1", TagGroupId = "TG-1", Name = "nested", DataType = "Int32", AccessLevel = TagAccessLevel.Read, TagConfig = "{}" });

        // SITE-A raw topology (for the cross-cluster rejection).
        db.DriverInstances.Add(new DriverInstance { DriverInstanceId = "DRV-2", ClusterId = "SITE-A", Name = "OTHER", DriverType = "Modbus", DriverConfig = "{}" });
        db.Devices.Add(new Device { DeviceId = "DEV-2", DriverInstanceId = "DRV-2", Name = "dev2", DeviceConfig = "{}" });
        db.Tags.Add(new Tag { TagId = "TAG-other", DeviceId = "DEV-2", Name = "temp", DataType = "Float", AccessLevel = TagAccessLevel.Read, TagConfig = "{}" });

        db.SaveChanges();
    }

    // ----- AddReferences -----

    /// <summary>Adding two raw tags persists two UnsTagReference rows for the equipment.</summary>
    [Fact]
    public async Task AddReferences_persists_rows()
    {
        var name = $"ref-add-{Guid.NewGuid():N}";
        Seed(name);
        var service = new UnsTreeService(Factory(name));

        var result = await service.AddReferencesAsync(EquipmentId, ["TAG-speed", "TAG-running"]);

        result.Ok.ShouldBeTrue();
        result.Error.ShouldBeNull();

        using var db = Db(name);
        var refs = db.UnsTagReferences.Where(r => r.EquipmentId == EquipmentId).ToList();
        refs.Count.ShouldBe(2);
        refs.Select(r => r.TagId).ShouldBe(new[] { "TAG-speed", "TAG-running" }, ignoreOrder: true);
        refs.All(r => r.DisplayNameOverride == null).ShouldBeTrue();
    }

    /// <summary>Loaded reference rows carry the computed RawPath and inherited (raw) datatype/access.</summary>
    [Fact]
    public async Task LoadReferences_projects_rawpath_and_inherited_type()
    {
        var name = $"ref-load-{Guid.NewGuid():N}";
        Seed(name);
        var service = new UnsTreeService(Factory(name));
        await service.AddReferencesAsync(EquipmentId, ["TAG-speed", "TAG-grouped"]);

        var rows = await service.LoadReferencesForEquipmentAsync(EquipmentId);

        rows.Count.ShouldBe(2);

        var speed = rows.Single(r => r.RawPath == "MAIN/dev1/speed");
        speed.EffectiveName.ShouldBe("speed");
        speed.DataType.ShouldBe("Float");
        speed.AccessLevel.ShouldBe(TagAccessLevel.Read);

        var nested = rows.Single(r => r.EffectiveName == "nested");
        nested.RawPath.ShouldBe("MAIN/dev1/grp/nested");
        nested.DataType.ShouldBe("Int32");
    }

    /// <summary>A raw tag whose cluster differs from the equipment's is rejected (cross-cluster).</summary>
    [Fact]
    public async Task AddReferences_cross_cluster_rejected()
    {
        var name = $"ref-xcluster-{Guid.NewGuid():N}";
        Seed(name);
        var service = new UnsTreeService(Factory(name));

        var result = await service.AddReferencesAsync(EquipmentId, ["TAG-other"]);

        result.Ok.ShouldBeFalse();
        result.Error.ShouldNotBeNull();
        result.Error.ShouldContain("cross-cluster");

        using var db = Db(name);
        db.UnsTagReferences.Any(r => r.EquipmentId == EquipmentId).ShouldBeFalse();
    }

    /// <summary>Re-referencing an already-referenced raw tag is rejected.</summary>
    [Fact]
    public async Task AddReferences_duplicate_tag_rejected()
    {
        var name = $"ref-dup-{Guid.NewGuid():N}";
        Seed(name);
        var service = new UnsTreeService(Factory(name));
        await service.AddReferencesAsync(EquipmentId, ["TAG-speed"]);

        var result = await service.AddReferencesAsync(EquipmentId, ["TAG-speed"]);

        result.Ok.ShouldBeFalse();
        result.Error.ShouldNotBeNull();
        result.Error.ShouldContain("already referenced");

        using var db = Db(name);
        db.UnsTagReferences.Count(r => r.EquipmentId == EquipmentId).ShouldBe(1);
    }

    /// <summary>A guard-reported collision (fake) becomes the mutation's readable failure; nothing is added.</summary>
    [Fact]
    public async Task AddReferences_guard_collision_rejected()
    {
        var name = $"ref-guard-{Guid.NewGuid():N}";
        Seed(name);
        var guard = new FakeGuard { Result = "'speed' already exists on equipment 'machine-1'." };
        var service = new UnsTreeService(Factory(name), guard);

        var result = await service.AddReferencesAsync(EquipmentId, ["TAG-speed"]);

        result.Ok.ShouldBeFalse();
        result.Error.ShouldBe("'speed' already exists on equipment 'machine-1'.");
        guard.LastProposedName.ShouldBe("speed");

        using var db = Db(name);
        db.UnsTagReferences.Any(r => r.EquipmentId == EquipmentId).ShouldBeFalse();
    }

    // ----- SetReferenceOverride -----

    /// <summary>Setting an override changes the effective name; clearing it falls back to the raw name.</summary>
    [Fact]
    public async Task SetReferenceOverride_sets_and_clears()
    {
        var name = $"ref-override-{Guid.NewGuid():N}";
        Seed(name);
        var service = new UnsTreeService(Factory(name));
        await service.AddReferencesAsync(EquipmentId, ["TAG-speed"]);

        var row = (await service.LoadReferencesForEquipmentAsync(EquipmentId)).Single();

        var set = await service.SetReferenceOverrideAsync(row.UnsTagReferenceId, "line-speed", row.RowVersion);
        set.Ok.ShouldBeTrue();

        var afterSet = (await service.LoadReferencesForEquipmentAsync(EquipmentId)).Single();
        afterSet.EffectiveName.ShouldBe("line-speed");
        afterSet.DisplayNameOverride.ShouldBe("line-speed");
        afterSet.RawPath.ShouldBe("MAIN/dev1/speed"); // raw path is unchanged by an override

        var clear = await service.SetReferenceOverrideAsync(afterSet.UnsTagReferenceId, "   ", afterSet.RowVersion);
        clear.Ok.ShouldBeTrue();

        var afterClear = (await service.LoadReferencesForEquipmentAsync(EquipmentId)).Single();
        afterClear.EffectiveName.ShouldBe("speed");
        afterClear.DisplayNameOverride.ShouldBeNull();
    }

    /// <summary>Setting an override that the guard reports as colliding is rejected.</summary>
    [Fact]
    public async Task SetReferenceOverride_guard_collision_rejected()
    {
        var name = $"ref-override-guard-{Guid.NewGuid():N}";
        Seed(name);
        var guard = new FakeGuard();
        var service = new UnsTreeService(Factory(name), guard);
        await service.AddReferencesAsync(EquipmentId, ["TAG-speed"]);
        var row = (await service.LoadReferencesForEquipmentAsync(EquipmentId)).Single();

        guard.Result = "collides with a virtual tag.";
        var result = await service.SetReferenceOverrideAsync(row.UnsTagReferenceId, "running", row.RowVersion);

        result.Ok.ShouldBeFalse();
        result.Error.ShouldBe("collides with a virtual tag.");
        guard.LastProposedName.ShouldBe("running");
    }

    // ----- RemoveReference -----

    /// <summary>Removing a reference deletes the row; a missing row is a no-op success.</summary>
    [Fact]
    public async Task RemoveReference_removes_row()
    {
        var name = $"ref-remove-{Guid.NewGuid():N}";
        Seed(name);
        var service = new UnsTreeService(Factory(name));
        await service.AddReferencesAsync(EquipmentId, ["TAG-speed"]);
        var row = (await service.LoadReferencesForEquipmentAsync(EquipmentId)).Single();

        var result = await service.RemoveReferenceAsync(row.UnsTagReferenceId, row.RowVersion);
        result.Ok.ShouldBeTrue();

        using var db = Db(name);
        db.UnsTagReferences.Any(r => r.EquipmentId == EquipmentId).ShouldBeFalse();

        // Already gone → idempotent success.
        var again = await service.RemoveReferenceAsync(row.UnsTagReferenceId, row.RowVersion);
        again.Ok.ShouldBeTrue();
    }

    // ----- Picker support -----

    /// <summary>The picker root is the equipment's own cluster node (structurally cluster-scoped).</summary>
    [Fact]
    public async Task LoadReferencePickerRoot_returns_cluster_node()
    {
        var name = $"ref-picker-{Guid.NewGuid():N}";
        Seed(name);
        var service = new UnsTreeService(Factory(name));

        var root = await service.LoadReferencePickerRootAsync(EquipmentId);

        root.ShouldNotBeNull();
        root!.Kind.ShouldBe(RawNodeKind.Cluster);
        root.EntityId.ShouldBe("MAIN");
        root.ClusterId.ShouldBe("MAIN");
        root.HasLazyChildren.ShouldBeTrue();
    }

    /// <summary>Select-all under a device returns every tag id in the device subtree.</summary>
    [Fact]
    public async Task LoadDescendantTagIds_device_returns_subtree_tags()
    {
        var name = $"ref-descend-{Guid.NewGuid():N}";
        Seed(name);
        var service = new UnsTreeService(Factory(name));

        var deviceNode = new RawNode
        {
            Kind = RawNodeKind.Device,
            Key = "dev:DEV-1",
            DisplayName = "dev1",
            ClusterId = "MAIN",
            EntityId = "DEV-1",
        };

        var ids = await service.LoadDescendantTagIdsAsync(deviceNode);

        ids.ShouldBe(new[] { "TAG-speed", "TAG-running", "TAG-grouped" }, ignoreOrder: true);
    }

    /// <summary>Select-all under a tag-group returns only the tags in that group's subtree.</summary>
    [Fact]
    public async Task LoadDescendantTagIds_group_returns_group_tags()
    {
        var name = $"ref-descend-grp-{Guid.NewGuid():N}";
        Seed(name);
        var service = new UnsTreeService(Factory(name));

        var groupNode = new RawNode
        {
            Kind = RawNodeKind.TagGroup,
            Key = "grp:TG-1",
            DisplayName = "grp",
            ClusterId = "MAIN",
            EntityId = "TG-1",
        };

        var ids = await service.LoadDescendantTagIdsAsync(groupNode);

        ids.ShouldBe(new[] { "TAG-grouped" });
    }
}