using AVEVA.Historian.Client.Wcf;

namespace AVEVA.Historian.Client.Tests;

public sealed class WcfHistoricalWriteProtocolTests
{
    // The exact 56-byte HistoryService.AddStreamValues "values" buffer captured live from the native
    // 2023 R2 client writing a historical Float sample (124.5) to a sandbox tag — see
    // docs/plans/revision-write-path.md §"R3.1 CAPTURED".
    private const string CapturedBufferHex =
        "4f4e0100380000002e00" +                     // "ON" + count(1) + totalLen(56) + payloadLen(46)
        "d51d3107e9f8664793b155d3d1aef544" +         // tag GUID 07311dd5-f8e9-4766-93b1-55d3d1aef544
        "70df38b1d101dd01" +                         // sample FILETIME
        "c000" +                                     // OpcQuality = 192
        "c0100100" +                                 // analog double descriptor
        "e64bcb74e201dd01" +                         // received/version FILETIME
        "000000000000f942";                          // double 124.5

    [Fact]
    public void SerializeAddStreamValuesBuffer_MatchesCapturedNativeBuffer()
    {
        var tagGuid = new Guid("07311dd5-f8e9-4766-93b1-55d3d1aef544");
        DateTime sampleTime = DateTime.FromFileTimeUtc(0x01dd01d1b138df70);
        DateTime receivedTime = DateTime.FromFileTimeUtc(0x01dd01e274cb4be6);

        byte[] actual = HistorianHistoricalWriteProtocol.SerializeAddStreamValuesBuffer(
            tagGuid, sampleTime, value: 124.5, receivedTime, quality: 192);

        Assert.Equal(Convert.FromHexString(CapturedBufferHex), actual);
    }

    [Fact]
    public void SerializeAddStreamValuesBuffer_HeaderDeclaresLengths()
    {
        byte[] buffer = HistorianHistoricalWriteProtocol.SerializeAddStreamValuesBuffer(
            Guid.NewGuid(), DateTime.UtcNow, value: 1.0, DateTime.UtcNow);

        Assert.Equal(56, buffer.Length);
        Assert.Equal(0x4E4F, BitConverter.ToUInt16(buffer, 0));      // "ON"
        Assert.Equal(1, BitConverter.ToUInt16(buffer, 2));           // sampleCount
        Assert.Equal((uint)buffer.Length, BitConverter.ToUInt32(buffer, 4));
        Assert.Equal(buffer.Length - 10, BitConverter.ToUInt16(buffer, 8));
    }
}