using Microsoft.Extensions.Logging.Abstractions;
using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;

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

/// <summary>
///     Guards the failure-visibility surface added for archreview 01/S-1: the applier must report a
///     failed rebuild (<see cref="AddressSpaceApplyOutcome.RebuildFailed"/>) and tally swallowed per-node
///     sink failures (<see cref="AddressSpaceApplyOutcome.FailedNodes"/> for Apply's own passes; the
///     <c>Materialise*</c> passes return their own failed-node counts) instead of reporting optimistic
///     success while the running address space is stale or partial.
/// </summary>
public sealed class AddressSpaceApplierFailureSurfaceTests
{
    // ---------------- T1: RebuildFailed ----------------

    /// <summary>A rebuild whose sink call throws is reported as attempted-but-failed, not optimistic success.</summary>
    [Fact]
    public void Apply_WhenRebuildThrows_ReportsRebuildFailed()
    {
        var sink = new ConfigurableThrowingSink { ThrowOnRebuild = true };
        var applier = new AddressSpaceApplier(sink, NullLogger<AddressSpaceApplier>.Instance);

        var outcome = applier.Apply(AddedEquipmentPlan("new"));

        outcome.RebuildCalled.ShouldBeTrue();
        outcome.RebuildFailed.ShouldBeTrue();
    }

    /// <summary>A clean apply reports no failure on either channel — the regression guard for the new fields.</summary>
    [Fact]
    public void Apply_HappyPath_ReportsNoFailure()
    {
        var sink = new ConfigurableThrowingSink();
        var applier = new AddressSpaceApplier(sink, NullLogger<AddressSpaceApplier>.Instance);

        var outcome = applier.Apply(AddedEquipmentPlan("new"));

        outcome.RebuildCalled.ShouldBeTrue();
        outcome.RebuildFailed.ShouldBeFalse();
        outcome.FailedNodes.ShouldBe(0);
    }

    // ---------------- T2: FailedNodes (removal-pass tally) ----------------

    /// <summary>A removal-pass alarm-condition write that throws is counted into FailedNodes (swallowed today).</summary>
    [Fact]
    public void Apply_WhenRemovalConditionWriteThrows_CountsFailedNodes()
    {
        var sink = new ConfigurableThrowingSink { ThrowOnAlarmWrite = true };
        var applier = new AddressSpaceApplier(sink, NullLogger<AddressSpaceApplier>.Instance);

        var outcome = applier.Apply(EquipmentRemovalPlan("eq-1"));

        outcome.RemovedNodes.ShouldBe(1);
        outcome.FailedNodes.ShouldBe(1);
    }

    // ---------------- fixtures ----------------

    private static AddressSpacePlan AddedEquipmentPlan(string id) => new(
        AddedEquipment: new[] { new EquipmentNode(id, id, "line-1") },
        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>());

    private static AddressSpacePlan EquipmentRemovalPlan(params string[] ids) => new(
        AddedEquipment: Array.Empty<EquipmentNode>(),
        RemovedEquipment: ids.Select(id => new EquipmentNode(id, id, "line-1")).ToArray(),
        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>());

    /// <summary>An <see cref="IOpcUaAddressSpaceSink"/> whose every sink call can be independently made to
    /// throw, so tests can drive each Safe* helper's catch branch. Non-throwing calls are no-ops.</summary>
    private sealed class ConfigurableThrowingSink : IOpcUaAddressSpaceSink
    {
        public bool ThrowOnRebuild { get; init; }
        public bool ThrowOnEnsureVariable { get; init; }
        public bool ThrowOnEnsureFolder { get; init; }
        public bool ThrowOnAlarmWrite { get; init; }
        public bool ThrowOnMaterialiseAlarm { get; init; }

        public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc) { }

        public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc)
        {
            if (ThrowOnAlarmWrite) throw new InvalidOperationException("simulated WriteAlarmCondition fault");
        }

        public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, bool isNative = false)
        {
            if (ThrowOnMaterialiseAlarm) throw new InvalidOperationException("simulated MaterialiseAlarmCondition fault");
        }

        public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName)
        {
            if (ThrowOnEnsureFolder) throw new InvalidOperationException("simulated EnsureFolder fault");
        }

        public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, string? historianTagname = null, bool isArray = false, uint? arrayLength = null)
        {
            if (ThrowOnEnsureVariable) throw new InvalidOperationException("simulated EnsureVariable fault");
        }

        public void RebuildAddressSpace()
        {
            if (ThrowOnRebuild) throw new InvalidOperationException("simulated RebuildAddressSpace fault");
        }

        public void RaiseNodesAddedModelChange(string affectedNodeId) { }
    }
}