using Google.Protobuf.WellKnownTypes;
using Microsoft.Extensions.Logging.Abstractions;
using Xunit;
using ZB.MOM.WW.HistorianGateway.Contracts.Grpc;
using ZB.MOM.WW.OtOpcUa.Core.Abstractions;

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

public sealed class GatewayHistorianDataSourceTests
{
    [Fact]
    public async Task ReadRaw_maps_samples_and_passes_args()
    {
        var fake = new FakeHistorianGatewayClient
        {
            RawSamples = new[]
            {
                new HistorianSample { Tag = "T", NumericValue = 1.0, OpcQuality = 192, Timestamp = Ts(2026, 1, 1, 0, 0, 0) },
                new HistorianSample { Tag = "T", NumericValue = 2.0, OpcQuality = 0, Timestamp = Ts(2026, 1, 1, 0, 0, 1) },
            },
        };
        var ds = new GatewayHistorianDataSource(fake, NullLogger<GatewayHistorianDataSource>.Instance);
        var start = new DateTime(2026, 1, 1, 0, 0, 0, DateTimeKind.Utc);
        var r = await ds.ReadRawAsync("T", start, start.AddMinutes(5), 100, TestContext.Current.CancellationToken);
        Assert.Equal(2, r.Samples.Count);
        Assert.Equal(0x80000000u, r.Samples[1].StatusCode); // Bad from quality 0
        Assert.Equal("T", fake.LastReadRawTag);
        // #687: asked from 1 ms before the window with room for AVEVA's boundary row (GatewayRawBoundaryRowTests).
        Assert.Equal(100 + RawAggregateReader.PreWindowAllowance, fake.LastReadRawMaxValues);
    }

    [Fact]
    public async Task ReadProcessed_uses_aggregate_mode_mapping()
    {
        var fake = new FakeHistorianGatewayClient();
        var ds = new GatewayHistorianDataSource(fake, NullLogger<GatewayHistorianDataSource>.Instance);
        await ds.ReadProcessedAsync("T", default, default, TimeSpan.FromSeconds(60), HistoryAggregateType.Total, TestContext.Current.CancellationToken);
        Assert.Equal(RetrievalMode.Integral, fake.LastAggregateMode);
        Assert.Equal(TimeSpan.FromSeconds(60), fake.LastAggregateInterval);
    }

    [Fact] // #681: the native buckets are stamped with the interval START and carry the Calculated bits
    public async Task ReadProcessed_native_buckets_are_stamped_at_the_interval_start_with_the_Calculated_bit()
    {
        var start = new DateTime(2026, 1, 1, 0, 0, 0, DateTimeKind.Utc);
        var fake = new FakeHistorianGatewayClient
        {
            AggregateSamples = new[]
            {
                new HistorianAggregateSample { Value = 7.0, OpcQuality = 192, StartTime = Timestamp.FromDateTime(start), EndTime = Timestamp.FromDateTime(start.AddMinutes(1)) },
                new HistorianAggregateSample { OpcQuality = 0, StartTime = Timestamp.FromDateTime(start.AddMinutes(1)), EndTime = Timestamp.FromDateTime(start.AddMinutes(2)) },
            },
        };
        var ds = new GatewayHistorianDataSource(fake, NullLogger<GatewayHistorianDataSource>.Instance);
        var r = await ds.ReadProcessedAsync("T", start, start.AddMinutes(2), TimeSpan.FromMinutes(1), HistoryAggregateType.TimeAverage, TestContext.Current.CancellationToken);
        Assert.Equal(new DateTime?[] { start, start.AddMinutes(1) }, r.Samples.Select(x => x.SourceTimestampUtc).ToArray());
        Assert.Equal(new[] { 0x00000401u, 0x809B0401u }, r.Samples.Select(x => x.StatusCode).ToArray());
    }

    [Fact]
    public async Task ReadProcessed_TimeAverage_requests_TimeWeightedAverage()
    {
        var fake = new FakeHistorianGatewayClient();
        var ds = new GatewayHistorianDataSource(fake, NullLogger<GatewayHistorianDataSource>.Instance);
        await ds.ReadProcessedAsync("T", default, default, TimeSpan.FromSeconds(60), HistoryAggregateType.TimeAverage, TestContext.Current.CancellationToken);
        Assert.Equal(RetrievalMode.TimeWeightedAverage, fake.LastAggregateMode);
    }

    [Theory] // #681 (was #679 BadAggregateNotSupported): served from a raw read, never a native retrieval mode
    [InlineData(HistoryAggregateType.Average)]
    [InlineData(HistoryAggregateType.Count)]
    [InlineData(HistoryAggregateType.Minimum)]
    [InlineData(HistoryAggregateType.Maximum)]
    public async Task ReadProcessed_per_sample_aggregate_reads_raw_not_a_retrieval_mode(HistoryAggregateType aggregate)
    {
        var fake = new FakeHistorianGatewayClient();
        var ds = new GatewayHistorianDataSource(fake, NullLogger<GatewayHistorianDataSource>.Instance);
        var t0 = new DateTime(2026, 1, 1, 0, 0, 0, DateTimeKind.Utc);
        await ds.ReadProcessedAsync("T", t0, t0.AddMinutes(1), TimeSpan.FromSeconds(60), aggregate, TestContext.Current.CancellationToken);
        Assert.Equal(0, fake.ReadAggregateCallCount);
        Assert.True(fake.ReadRawCallCount >= 1); // the window, plus the earlier-data probe when the range matters
    }

    [Theory] // no AVEVA mode and not a per-sample aggregate: not supported, gateway never called, no failure recorded
    [InlineData(HistoryAggregateType.TimeAverage2)]
    [InlineData(HistoryAggregateType.PercentGood)]
    public async Task ReadProcessed_unsupported_aggregate_throws_without_calling_gateway_or_recording_failure(HistoryAggregateType aggregate)
    {
        var fake = new FakeHistorianGatewayClient();
        var ds = new GatewayHistorianDataSource(fake, NullLogger<GatewayHistorianDataSource>.Instance);
        await Assert.ThrowsAsync<HistoryAggregateNotSupportedException>(() => ds.ReadProcessedAsync(
            "T", default, default, TimeSpan.FromSeconds(60), aggregate, TestContext.Current.CancellationToken));
        Assert.Equal(0, fake.ReadAggregateCallCount);
        Assert.Equal(0, fake.ReadRawCallCount);
        var h = ds.GetHealthSnapshot();
        Assert.Equal(0, h.TotalFailures);
        Assert.Equal(0, h.TotalQueries);
    }

    [Fact]
    public async Task ReadAtTime_aligns_one_snapshot_per_timestamp_with_gaps_Bad()
    {
        var fake = new FakeHistorianGatewayClient();
        var t0 = new DateTime(2026, 1, 1, 0, 0, 0, DateTimeKind.Utc);
        var t1 = t0.AddSeconds(1);
        fake.AtTimeSamples = new[] { new HistorianSample { NumericValue = 5.0, OpcQuality = 192, Timestamp = Timestamp.FromDateTime(t0) } };
        var ds = new GatewayHistorianDataSource(fake, NullLogger<GatewayHistorianDataSource>.Instance);
        var r = await ds.ReadAtTimeAsync("T", new[] { t0, t1 }, TestContext.Current.CancellationToken);
        Assert.Equal(2, r.Samples.Count);          // exactly one per requested ts, in order
        Assert.Equal(5.0, r.Samples[0].Value);
        Assert.Equal(0x80000000u, r.Samples[1].StatusCode); // gap → Bad at requested ts
    }

    [Fact] // #690: an at-time NULL (histsdk: value 0 + Bad) is null + Bad, like the SQL backends' AtTime of a Bad sample
    public async Task ReadAtTime_of_a_NULL_row_carries_no_value()
    {
        var fake = new FakeHistorianGatewayClient();
        var t0 = new DateTime(2026, 1, 1, 0, 0, 0, DateTimeKind.Utc);
        fake.AtTimeSamples = new[]
        {
            new HistorianSample { NumericValue = 0, OpcQuality = 0, Quality = 1, Timestamp = Timestamp.FromDateTime(t0) },
        };
        var ds = new GatewayHistorianDataSource(fake, NullLogger<GatewayHistorianDataSource>.Instance);
        var r = await ds.ReadAtTimeAsync("T", new[] { t0 }, TestContext.Current.CancellationToken);
        Assert.Null(r.Samples[0].Value);
        Assert.Equal(0x80000000u, r.Samples[0].StatusCode);
    }

    [Fact]
    public async Task Empty_window_is_not_a_fault()
    {
        var fake = new FakeHistorianGatewayClient { RawSamples = Array.Empty<HistorianSample>() };
        var ds = new GatewayHistorianDataSource(fake, NullLogger<GatewayHistorianDataSource>.Instance);
        var r = await ds.ReadRawAsync("T", default, default, 10, TestContext.Current.CancellationToken);
        Assert.Empty(r.Samples);                    // GoodNoData-empty, no throw
    }

    [Fact]
    public async Task Disposing_data_source_disposes_client()
    {
        var fake = new FakeHistorianGatewayClient();
        var ds = new GatewayHistorianDataSource(fake, NullLogger<GatewayHistorianDataSource>.Instance);
        await ds.DisposeAsync();
        Assert.Equal(1, fake.DisposeCallCount);
    }

    [Fact]
    public void Dispose_via_sync_path_disposes_client()
    {
        var fake = new FakeHistorianGatewayClient();
        var ds = new GatewayHistorianDataSource(fake, NullLogger<GatewayHistorianDataSource>.Instance);
        ((IDisposable)ds).Dispose();
        Assert.Equal(1, fake.DisposeCallCount);
    }

    // Ts(...) builds a Google.Protobuf.WellKnownTypes.Timestamp from UTC parts.
    private static Timestamp Ts(int y, int mo, int d, int h, int mi, int s)
        => Timestamp.FromDateTime(new DateTime(y, mo, d, h, mi, s, DateTimeKind.Utc));
}