histsdk/src/AVEVA.Historian.Client/Protocol/Historian2020ProtocolDialect.cs

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

namespace AVEVA.Historian.Client.Protocol;

internal sealed class Historian2020ProtocolDialect
{
    private readonly HistorianClientOptions _options;

    public Historian2020ProtocolDialect(HistorianClientOptions options)
    {
        _options = options ?? throw new ArgumentNullException(nameof(options));
    }

    private bool UseGrpc => _options.Transport == HistorianTransport.RemoteGrpc;

    public IAsyncEnumerable<HistorianSample> ReadRawAsync(string tag, DateTime startUtc, DateTime endUtc, int maxValues, CancellationToken cancellationToken)
    {
        return UseGrpc
            ? new HistorianGrpcReadOrchestrator(_options).ReadRawAsync(tag, startUtc, endUtc, maxValues, cancellationToken)
            : new HistorianWcfReadOrchestrator(_options).ReadRawAsync(tag, startUtc, endUtc, maxValues, cancellationToken);
    }

    public IAsyncEnumerable<HistorianAggregateSample> ReadAggregateAsync(string tag, DateTime startUtc, DateTime endUtc, RetrievalMode mode, TimeSpan interval, CancellationToken cancellationToken)
    {
        return UseGrpc
            ? new HistorianGrpcReadOrchestrator(_options).ReadAggregateAsync(tag, startUtc, endUtc, mode, interval, cancellationToken)
            : new HistorianWcfReadOrchestrator(_options).ReadAggregateAsync(tag, startUtc, endUtc, mode, interval, cancellationToken);
    }

    public Task<IReadOnlyList<HistorianSample>> ReadAtTimeAsync(string tag, IReadOnlyList<DateTime> timestampsUtc, CancellationToken cancellationToken)
    {
        cancellationToken.ThrowIfCancellationRequested();
        return UseGrpc
            ? new HistorianGrpcReadOrchestrator(_options).ReadAtTimeAsync(tag, timestampsUtc, cancellationToken)
            : new HistorianWcfReadOrchestrator(_options).ReadAtTimeAsync(tag, timestampsUtc, cancellationToken);
    }

    public IAsyncEnumerable<HistorianBlock> ReadBlocksAsync(string tag, DateTime startUtc, DateTime endUtc, CancellationToken cancellationToken)
    {
        return Missing<HistorianBlock>("StartBlockRetrievalQuery", cancellationToken);
    }

    public IAsyncEnumerable<HistorianEvent> ReadEventsAsync(DateTime startUtc, DateTime endUtc, HistorianEventFilter? filter, CancellationToken cancellationToken)
    {
        return UseGrpc
            ? new HistorianGrpcEventOrchestrator(_options).ReadEventsAsync(startUtc, endUtc, filter, cancellationToken)
            : new HistorianWcfEventOrchestrator(_options).ReadEventsAsync(startUtc, endUtc, filter, cancellationToken);
    }

    public Task<HistorianConnectionStatus> GetConnectionStatusAsync(CancellationToken cancellationToken)
    {
        cancellationToken.ThrowIfCancellationRequested();

        // Over gRPC (2023 R2) the status is measured from the gRPC handshake (the WCF synthesize-from-
        // probe path uses the MDAS binding, which can't reach the gRPC port). Non-gRPC stays on WCF.
        return UseGrpc
            ? HistorianGrpcStatusClient.GetConnectionStatusAsync(_options, cancellationToken)
            : Wcf.HistorianWcfStatusClient.GetConnectionStatusAsync(_options, cancellationToken);
    }

    public Task<HistorianStoreForwardStatus> GetStoreForwardStatusAsync(CancellationToken cancellationToken)
    {
        cancellationToken.ThrowIfCancellationRequested();

        // Over gRPC (2023 R2) we return a MEASURED idle-state: the client actually contacts the server
        // (GetHistorianConsoleStatus) and reports ErrorOccurred when unreachable. The active-SF buffer
        // magnitude lives behind the D2 storage-engine console wall and stays false. Non-gRPC transports
        // keep the synthesized all-false (no SF sidecar to probe). See R4.3 §9.7.
        return UseGrpc
            ? HistorianGrpcStatusClient.GetStoreForwardStatusAsync(_options, cancellationToken)
            : Wcf.HistorianWcfStatusClient.GetStoreForwardStatusAsync(_options, cancellationToken);
    }

    public Task<string?> GetSystemParameterAsync(string name, CancellationToken cancellationToken)
    {
        cancellationToken.ThrowIfCancellationRequested();
        ArgumentException.ThrowIfNullOrWhiteSpace(name);
        return UseGrpc
            ? HistorianGrpcStatusClient.GetSystemParameterAsync(_options, name, cancellationToken)
            : Wcf.HistorianWcfStatusClient.GetSystemParameterAsync(_options, name, cancellationToken);
    }

    public Task<string?> GetServerTimeZoneAsync(CancellationToken cancellationToken)
    {
        cancellationToken.ThrowIfCancellationRequested();

        // 2023 R2 gRPC returns the real server time-zone name; the 2020 WCF
        // GetSystemTimeZoneName is a client-side stub (empty value), so there is no evidence-backed
        // value to return on that transport — fail closed rather than hand back an empty string.
        if (!UseGrpc)
        {
            throw new ProtocolEvidenceMissingException("GetSystemTimeZoneName (2020 WCF stub — gRPC/2023R2 only)");
        }

        return HistorianGrpcStatusClient.GetSystemTimeZoneNameAsync(_options, cancellationToken);
    }

    public Task<string?> GetRuntimeParameterAsync(string name, CancellationToken cancellationToken)
    {
        cancellationToken.ThrowIfCancellationRequested();
        ArgumentException.ThrowIfNullOrWhiteSpace(name);
        return UseGrpc
            ? HistorianGrpcStatusClient.GetRuntimeParameterAsync(_options, name, cancellationToken)
            : Wcf.HistorianWcfStatusClient.GetRuntimeParameterAsync(_options, name, cancellationToken);
    }

    public Task<IReadOnlyList<Models.HistorianTagExtendedProperty>> GetTagExtendedPropertiesAsync(string tag, CancellationToken cancellationToken)
    {
        cancellationToken.ThrowIfCancellationRequested();
        ArgumentException.ThrowIfNullOrWhiteSpace(tag);
        return UseGrpc
            ? Grpc.HistorianGrpcTagClient.GetTagExtendedPropertiesAsync(_options, tag, cancellationToken)
            : Wcf.HistorianWcfTagExtendedPropertyClient.GetTagExtendedPropertiesAsync(_options, tag, cancellationToken);
    }

    public Task<HistorianSqlResult> ExecuteSqlCommandAsync(string command, HistorianSqlExecuteOption option, CancellationToken cancellationToken)
    {
        cancellationToken.ThrowIfCancellationRequested();
        ArgumentException.ThrowIfNullOrWhiteSpace(command);
        return UseGrpc
            ? Grpc.HistorianGrpcSqlClient.ExecuteSqlCommandAsync(_options, command, option, cancellationToken)
            : Wcf.HistorianWcfSqlClient.ExecuteSqlCommandAsync(_options, command, option, cancellationToken);
    }

    private static async IAsyncEnumerable<T> Missing<T>(
        string operation,
        [System.Runtime.CompilerServices.EnumeratorCancellation] CancellationToken cancellationToken)
    {
        await Task.Yield();
        cancellationToken.ThrowIfCancellationRequested();
        throw new ProtocolEvidenceMissingException(operation);
#pragma warning disable CS0162
        yield break;
#pragma warning restore CS0162
    }
}