using AVEVA.Historian.Client.Models;
using AVEVA.Historian.Client.Wcf;

namespace AVEVA.Historian.Client.Tests;

public sealed class WcfEventWriteProtocolTests
{
    // Golden bytes captured from a native AddStreamedValue(HistorianEvent) over WCF (AddS2.pBuf),
    // instrument-wcf-writemessage, event-send capture A (Type="User.Write").
    private const string CaptureAddS2PBufBase64 =
        "T1MBANMAAADJAEWBOzXwXUZNolOHGu9JsyHwZ9L7+QDdAcAAwACNEbJ2OdoXacNJkFutCzR+krSAst37" +
        "+QDdAQkSAFJldGVzdFNka0V2ZW50U2VuZAkKAFVzZXIuV3JpdGUFAAIACQYAU291cmNlQyYAEgBSAGUA" +
        "dABlAHMAdABTAGQAawBFAHYAZQBuAHQAUwBlAG4AZAAJCgBUZXN0TWFya2VyQyoAFABoAGkAcwB0AHMA" +
        "ZABrAC0AUgAyAC4AMQAtAGMAYQBwAHQAdQByAGUA";

    [Fact]
    public void SerializeAddStreamValuesBufferMatchesInstrumentedNativeEventSend()
    {
        // Exact field values recovered from capture A's pBuf.
        Guid eventId = new("da3976b2-6917-49c3-905b-ad0b347e92b4");
        DateTime eventTimeUtc = DateTime.FromFileTimeUtc(134264637562710000L);
        DateTime receivedTimeUtc = DateTime.FromFileTimeUtc(134264637563449984L);

        HistorianEvent evt = new(
            Id: eventId,
            EventTimeUtc: eventTimeUtc,
            ReceivedTimeUtc: receivedTimeUtc,
            Type: "User.Write",
            SourceName: string.Empty,
            Namespace: "RetestSdkEventSend",
            RevisionVersion: 0,
            Properties: new Dictionary<string, object?>
            {
                ["Source"] = "RetestSdkEventSend",
                ["TestMarker"] = "histsdk-R2.1-capture",
            });

        // The capture's MDAS length marker excluded the final trailing pad byte, so the golden
        // bytes are the 210-byte deterministic content; the serializer appends one pad byte
        // (total 211) to satisfy the server's packet-length == buffer-size check.
        byte[] expectedContent = Convert.FromBase64String(CaptureAddS2PBufBase64);
        byte[] actual = HistorianEventWriteProtocol.SerializeAddStreamValuesBuffer(evt, receivedTimeUtc);

        Assert.Equal(expectedContent.Length + 1, actual.Length);
        Assert.Equal(expectedContent, actual[..expectedContent.Length]);
        Assert.Equal(0, actual[^1]);
        // The declared packet length (UInt32 @0x04) equals the delivered buffer length.
        Assert.Equal((uint)actual.Length, BitConverter.ToUInt32(actual, 4));
    }

    [Fact]
    public void BufferFramingFieldsAreDerivedFromValueBlobLength()
    {
        HistorianEvent evt = new(
            Id: new("da3976b2-6917-49c3-905b-ad0b347e92b4"),
            EventTimeUtc: DateTime.FromFileTimeUtc(134264637562710000L),
            ReceivedTimeUtc: DateTime.FromFileTimeUtc(134264637563449984L),
            Type: "User.Write",
            SourceName: string.Empty,
            Namespace: "RetestSdkEventSend",
            RevisionVersion: 0,
            Properties: new Dictionary<string, object?> { ["Source"] = "RetestSdkEventSend", ["TestMarker"] = "histsdk-R2.1-capture" });

        byte[] buf = HistorianEventWriteProtocol.SerializeAddStreamValuesBuffer(evt, evt.ReceivedTimeUtc);

        Assert.Equal(0x534F, BitConverter.ToUInt16(buf, 0)); // "OS"
        Assert.Equal(1, BitConverter.ToUInt16(buf, 2));      // sampleCount
        // Declared packet length (UInt32 @0x04) equals the delivered buffer length (incl. pad).
        Assert.Equal((uint)buf.Length, BitConverter.ToUInt32(buf, 4));
        // Inner length (UInt16 @0x08) = buffer length - 10.
        Assert.Equal((ushort)(buf.Length - 10), BitConverter.ToUInt16(buf, 8));
        // CM_EVENT tag id at the head of the value blob.
        Assert.Equal(HistorianEventWriteProtocol.CmEventTagId, new Guid(buf.AsSpan(10, 16).ToArray()));
    }

    [Fact]
    public void NonStringPropertyValueThrowsProtocolEvidenceMissing()
    {
        HistorianEvent evt = new(
            Id: Guid.NewGuid(),
            EventTimeUtc: new DateTime(2026, 6, 20, 12, 0, 0, DateTimeKind.Utc),
            ReceivedTimeUtc: new DateTime(2026, 6, 20, 12, 0, 0, DateTimeKind.Utc),
            Type: "User.Write",
            SourceName: string.Empty,
            Namespace: "ns",
            RevisionVersion: 0,
            Properties: new Dictionary<string, object?> { ["Count"] = 5 });

        Assert.Throws<ProtocolEvidenceMissingException>(
            () => HistorianEventWriteProtocol.SerializeAddStreamValuesBuffer(evt, evt.ReceivedTimeUtc));
    }
}