using Xunit;
using ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian;   // AlarmHistorianEvent
using ZB.MOM.WW.OtOpcUa.Core.Abstractions;      // AlarmSeverity
using ZB.MOM.WW.OtOpcUa.Driver.Historian.Gateway.Mapping;

namespace ZB.MOM.WW.OtOpcUa.Driver.Historian.Gateway.Tests.Mapping;

public sealed class AlarmEventMapperTests
{
    [Fact]
    public void A_direct_event_has_a_nonzero_wire_id_that_survives_repeated_mapping()
    {
        var alarm = new AlarmHistorianEvent("A", "S", "N", "LimitAlarm", AlarmSeverity.High,
            "Activated", "m", "system", null, new DateTime(2026, 1, 1, 0, 0, 0, DateTimeKind.Utc));
        var first = AlarmEventMapper.ToHistorianEvent(alarm).Id;
        Assert.True(Guid.TryParse(first, out var id), $"Expected a delivery GUID; received '{first}'.");
        Assert.NotEqual(Guid.Empty, id);
        Assert.Equal(first, AlarmEventMapper.ToHistorianEvent(alarm).Id);
    }

    [Fact]
    public void Maps_source_time_type_and_rich_properties()
    {
        var a = new AlarmHistorianEvent("A1", "Area/Line/Pump1", "HiHi", "LimitAlarm",
            AlarmSeverity.High, "Activated", "Temp high", "operator1", "ack note",
            new DateTime(2026, 1, 1, 0, 0, 0, DateTimeKind.Utc));
        var e = AlarmEventMapper.ToHistorianEvent(a);
        Assert.Equal("Area/Line/Pump1", e.SourceName);
        Assert.Equal("LimitAlarm", e.Type);
        Assert.Equal(new DateTime(2026, 1, 1, 0, 0, 0, DateTimeKind.Utc), e.EventTime.ToDateTime());
        Assert.Equal(a.DeliveryId.ToString("D"), e.Id);
        Assert.Equal("A1", e.Properties["AlarmId"]);
        Assert.Equal("HiHi", e.Properties["AlarmName"]);
        Assert.Equal("Activated", e.Properties["EventKind"]);
        // Severity is the AlarmHistorianEvent.Severity XML doc contract: "Mapped to Historian's
        // numeric priority on the sink side" — NOT the .NET enum name. EventMapper.ParseSeverity on
        // the read side int.TryParse()s this same property, so a non-numeric string (the old bug:
        // alarm.Severity.ToString() == "High") silently always read back as the minimum severity (1).
        Assert.Equal("700", e.Properties["Severity"]);
        Assert.Equal("operator1", e.Properties["User"]);
        Assert.Equal("ack note", e.Properties["Comment"]);
        Assert.Equal("Temp high", e.Properties["Message"]);
    }

    /// <summary>
    /// Driver.Historian.Gateway-001 regression: the write side (<see cref="AlarmEventMapper"/>) and
    /// the read side (<see cref="EventMapper"/>) must agree on the wire representation of severity —
    /// a numeric OPC UA Part 9 priority string, matching the convention already used elsewhere in the
    /// codebase for the same enum (<c>NativeAlarmProjector.MapSeverity</c>: Low=200/Medium=500/
    /// High=700/Critical=900). Round-tripping through both mappers must reproduce the numeric severity,
    /// not collapse to the minimum every time.
    /// </summary>
    [Theory]
    [InlineData(AlarmSeverity.Low, (ushort)200)]
    [InlineData(AlarmSeverity.Medium, (ushort)500)]
    [InlineData(AlarmSeverity.High, (ushort)700)]
    [InlineData(AlarmSeverity.Critical, (ushort)900)]
    public void Severity_round_trips_through_EventMapper_as_numeric_priority(AlarmSeverity severity, ushort expected)
    {
        var a = new AlarmHistorianEvent("A1", "Area/Line/Pump1", "HiHi", "LimitAlarm",
            severity, "Activated", "m", "operator1", null,
            new DateTime(2026, 1, 1, 0, 0, 0, DateTimeKind.Utc));

        var wire = AlarmEventMapper.ToHistorianEvent(a);
        var readBack = EventMapper.ToHistoricalEvent(wire);

        Assert.Equal(expected, readBack.Severity);
    }

    [Fact]
    public void Null_comment_is_omitted_not_null()
    {
        var a = new AlarmHistorianEvent("A", "S", "N", "DiscreteAlarm", AlarmSeverity.Low, "Cleared", "m", "system", null,
            new DateTime(2026, 1, 1, 0, 0, 0, DateTimeKind.Utc));
        Assert.False(AlarmEventMapper.ToHistorianEvent(a).Properties.ContainsKey("Comment"));
    }

    [Fact]
    public void A_blank_condition_id_still_has_delivery_identity_and_adds_no_condition_property()
    {
        // Condition identity and event delivery identity serve different purposes.
        var a = new AlarmHistorianEvent("", "S", "N", "DiscreteAlarm", AlarmSeverity.Low, "Cleared", "m", "system", null,
            new DateTime(2026, 1, 1, 0, 0, 0, DateTimeKind.Utc));
        var e = AlarmEventMapper.ToHistorianEvent(a);
        Assert.Equal(a.DeliveryId.ToString("D"), e.Id);
        Assert.False(e.Properties.ContainsKey("AlarmId"));
    }

    [Fact]
    public void An_explicitly_empty_delivery_id_is_rejected_instead_of_reminted()
    {
        var alarm = new AlarmHistorianEvent("A", "S", "N", "LimitAlarm", AlarmSeverity.High,
            "Activated", "m", "system", null, DateTime.UtcNow) { DeliveryId = Guid.Empty };
        Assert.Throws<ArgumentException>(() => AlarmEventMapper.ToHistorianEvent(alarm));
    }
}