namespace ZB.MOM.WW.OtOpcUa.Core.Abstractions;

/// <summary>
///     Driver capability for historical-data reads (OPC UA HistoryRead). Optional —
///     only drivers whose backends carry historian data implement this. Currently:
///     Galaxy (Wonderware Historian via the optional plugin), OPC UA Client (forward
///     to upstream server).
/// </summary>
public interface IHistoryProvider
{
    /// <summary>
    ///     Read raw historical samples for a single attribute over a time range.
    ///     The Core wraps this with continuation-point handling.
    /// </summary>
    Task<HistoryReadResult> ReadRawAsync(
        string fullReference,
        DateTime startUtc,
        DateTime endUtc,
        uint maxValuesPerNode,
        CancellationToken cancellationToken);

    /// <summary>
    ///     Read processed (aggregated) samples — interval-bucketed average / min / max / etc.
    ///     Optional — drivers that only support raw history can throw <see cref="NotSupportedException"/>.
    /// </summary>
    Task<HistoryReadResult> ReadProcessedAsync(
        string fullReference,
        DateTime startUtc,
        DateTime endUtc,
        TimeSpan interval,
        HistoryAggregateType aggregate,
        CancellationToken cancellationToken);
}

/// <summary>Result of a HistoryRead call.</summary>
/// <param name="Samples">Returned samples in chronological order.</param>
/// <param name="ContinuationPoint">Opaque token for the next call when more samples are available; null when complete.</param>
public sealed record HistoryReadResult(
    IReadOnlyList<DataValueSnapshot> Samples,
    byte[]? ContinuationPoint);

/// <summary>Aggregate function for processed history reads. Mirrors OPC UA Part 13 standard aggregates.</summary>
public enum HistoryAggregateType
{
    Average,
    Minimum,
    Maximum,
    Total,
    Count,
}