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

namespace ZB.MOM.WW.OtOpcUa.Driver.Historian.Sql.Common;

/// <summary>A stored sample as read back: source time, typed value and stored status.</summary>
/// <param name="TimeUtc">Source timestamp (UTC).</param>
/// <param name="Value">Typed value (<see cref="HistorianValue.Empty"/> for an outage marker).</param>
/// <param name="Status">Stored OPC UA status code.</param>
public readonly record struct StoredSample(DateTime TimeUtc, HistorianValue Value, uint Status)
{
    /// <summary>Severity Good or Uncertain, and a value present (an Empty sample is an outage marker).</summary>
    public bool IsUsable => !StatusBits.IsBad(Status) && Value.Kind != HistorianValueKind.Empty;

    /// <summary>Usable with severity Good.</summary>
    public bool IsGood => IsUsable && StatusBits.IsGood(Status);

    /// <summary>
    ///     Builds a sample from stored columns, applying the quality clamp: an Empty (no-value) row whose stored status
    ///     is not Bad is served as <c>BadNoData</c> — defence in depth for rows written before the writer forced every
    ///     Empty sample Bad.
    /// </summary>
    /// <param name="timeUtc">Source timestamp (UTC).</param>
    /// <param name="value">Stored value.</param>
    /// <param name="status">Stored status code.</param>
    /// <returns>The sample, clamped.</returns>
    public static StoredSample FromStored(DateTime timeUtc, HistorianValue value, uint status)
    {
        if (value.Kind == HistorianValueKind.Empty && !StatusBits.IsBad(status))
            status = HistorianStatusCodes.BadNoData;
        return new StoredSample(timeUtc, value, status);
    }
}