using System.Buffers.Binary;
using AVEVA.Historian.Client.Models;
using AVEVA.Historian.Client.Wcf;

namespace AVEVA.Historian.Client.Tests;

public sealed class WcfHistoricalWriteProtocolTests
{
    // Exact HistoryService.AddStreamValues "values" buffers captured live from the native 2023 R2
    // client writing one historical sample to a sandbox tag of each analog type — see
    // docs/plans/revision-write-path.md §"R3.1 CAPTURED". The value descriptor (C0 10 01 00) is
    // constant across types; only the value width differs.
    [Theory]
    [InlineData(HistorianDataType.Float, 124.5,
        "4f4e0100380000002e00d51d3107e9f8664793b155d3d1aef54470df38b1d101dd01c000c0100100e64bcb74e201dd01000000000000f942")]
    [InlineData(HistorianDataType.Double, 124.5,
        "4f4e01003c0000003200" + "7f970bb0b5a7344bb7bf6899ff06d027" + "c07d5f23d701dd01" + "c000" + "c0100100" + "08eff1e6e701dd01" + "000000000000000000205f40")]
    [InlineData(HistorianDataType.Int2, 1234d,
        "4f4e0100360000002c00" + "35bb0ca5865a7f4498f06bf4e4d9ab23" + "f012f356d701dd01" + "c000" + "c0100100" + "9546841ae801dd01" + "00000000d204")]
    [InlineData(HistorianDataType.Int4, 12345d,
        "4f4e0100380000002e00" + "ca9735f7f841b244b56f9c14ccfeac32" + "b09bc72fd701dd01" + "c000" + "c0100100" + "104b59f3e701dd01" + "0000000039300000")]
    [InlineData(HistorianDataType.UInt4, 305419896d,
        "4f4e0100380000002e00" + "e7ae22d8e4cc65439ebd8bcb09402974" + "602d6663d701dd01" + "c000" + "c0100100" + "498af726e801dd01" + "0000000078563412")]
    public void SerializeAddStreamValuesBuffer_MatchesCapturedNativeBuffer(HistorianDataType dataType, double value, string capturedHex)
    {
        byte[] captured = Convert.FromHexString(capturedHex);

        // The GUID + both FILETIMEs sit at fixed offsets (the value width varies after them).
        var tagGuid = new Guid(captured.AsSpan(10, 16).ToArray());
        long sampleFt = BinaryPrimitives.ReadInt64LittleEndian(captured.AsSpan(26, 8));
        long receivedFt = BinaryPrimitives.ReadInt64LittleEndian(captured.AsSpan(40, 8));

        byte[] actual = HistorianHistoricalWriteProtocol.SerializeAddStreamValuesBuffer(
            tagGuid,
            dataType,
            DateTime.FromFileTimeUtc(sampleFt),
            value,
            DateTime.FromFileTimeUtc(receivedFt),
            quality: 192);

        Assert.Equal(captured, actual);
    }

    [Fact]
    public void SerializeAddStreamValuesBuffer_UnsupportedType_Throws()
    {
        Assert.Throws<ProtocolEvidenceMissingException>(() =>
            HistorianHistoricalWriteProtocol.SerializeAddStreamValuesBuffer(
                Guid.NewGuid(), HistorianDataType.SingleByteString, DateTime.UtcNow, 1.0, DateTime.UtcNow));
    }

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

        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));
    }
}