using Xunit;
using ZB.MOM.WW.OtOpcUa.Core.Abstractions;        // HistoryAggregateType
using ZB.MOM.WW.HistorianGateway.Contracts.Grpc;  // RetrievalMode
using ZB.MOM.WW.OtOpcUa.Driver.Historian.Gateway.Mapping;

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

public sealed class AggregateModeMapperTests
{
    [Theory]
    [InlineData(HistoryAggregateType.TimeAverage, RetrievalMode.TimeWeightedAverage)]
    [InlineData(HistoryAggregateType.Minimum, RetrievalMode.MinimumWithTime)]
    [InlineData(HistoryAggregateType.Maximum, RetrievalMode.MaximumWithTime)]
    [InlineData(HistoryAggregateType.Total,   RetrievalMode.Integral)]
    public void Maps_each_aggregate(HistoryAggregateType a, RetrievalMode expected)
        => Assert.Equal(expected, AggregateModeMapper.ToRetrievalMode(a));

    [Fact] // matrix guard: every member is either mapped or explicitly reported as not supported
    public void Every_aggregate_member_is_mapped_or_reports_not_supported()
    {
        var original = new[]
        {
            HistoryAggregateType.Minimum, HistoryAggregateType.Maximum,
            HistoryAggregateType.Total, HistoryAggregateType.TimeAverage,
        };
        foreach (var a in Enum.GetValues<HistoryAggregateType>())
        {
            if (original.Contains(a))
                _ = AggregateModeMapper.ToRetrievalMode(a);
            else
                Assert.Throws<HistoryAggregateNotSupportedException>(() => AggregateModeMapper.ToRetrievalMode(a));
        }
    }

    [Theory] // #679: AVEVA has no arithmetic mean and no sample count (Counter is a rollover increase)
    [InlineData(HistoryAggregateType.Average)]
    [InlineData(HistoryAggregateType.Count)]
    public void Average_and_Count_are_not_supported(HistoryAggregateType a)
        => Assert.Throws<HistoryAggregateNotSupportedException>(() => AggregateModeMapper.ToRetrievalMode(a));

    [Fact] // #682: the served (= advertised) set is exactly what the mapper maps, and the data source returns it
    public void Served_is_exactly_the_mapped_members_and_the_data_source_declares_it()
    {
        Assert.Equal(
            new[] { HistoryAggregateType.Minimum, HistoryAggregateType.Maximum, HistoryAggregateType.Total, HistoryAggregateType.TimeAverage }
                .OrderBy(a => a),
            AggregateModeMapper.Served.OrderBy(a => a));
        foreach (var a in Enum.GetValues<HistoryAggregateType>().Where(a => !AggregateModeMapper.Served.Contains(a)))
            Assert.Throws<HistoryAggregateNotSupportedException>(() => AggregateModeMapper.ToRetrievalMode(a));

        var source = new GatewayHistorianDataSource(
            new FakeHistorianGatewayClient(), Microsoft.Extensions.Logging.Abstractions.NullLogger<GatewayHistorianDataSource>.Instance);
        Assert.Same(AggregateModeMapper.Served, source.SupportedAggregates);
    }

    [Fact]
    public void Undefined_value_is_a_programming_error_not_a_not_supported()
        => Assert.Throws<ArgumentOutOfRangeException>(() => AggregateModeMapper.ToRetrievalMode((HistoryAggregateType)9999));
}