namespace ZB.MOM.WW.OtOpcUa.Driver.Sql.Contracts;

/// <summary>
///     The keys <c>SqlBrowseSession</c> states in a browsed column's <c>AttributeInfo.AddressFields</c>, and
///     that <c>RawBrowseCommitMapper</c> reads back when it builds the committed tag's <c>TagConfig</c>.
///     <para><b>Why a shared constant rather than a literal at each end.</b> A Sql tag's binding is a tuple
///     (table + column + which row), so — exactly as for MQTT's Sparkplug tuple and
///     <c>MqttTagConfigKeys</c> — the producing session states the parts and the mapper must never
///     re-infer them. Two independently spelled string literals agree by coincidence, and a disagreement is
///     silent: the mapper simply sees no field, and emits a config missing whatever the session was trying
///     to say. That is precisely how Gitea #552 shipped — a wide-row blob with no <c>rowSelector</c>, which
///     both <see cref="SqlEquipmentTagParser"/> and the authoring gate refuse.</para>
///     <para>These are the <em>browse channel's</em> names, not the tag blob's schema. Three of them happen
///     to match a <c>TagConfig</c> key because the mapper writes them straight through;
///     <see cref="TopByTimestamp"/> matches the key <em>nested inside</em> <c>rowSelector</c> — deliberately
///     not spelled <c>timestampColumn</c>, which is the blob's unrelated top-level source-timestamp
///     field.</para>
/// </summary>
public static class SqlBrowseAddressFields
{
    /// <summary>The catalog schema owning the browsed column's table (e.g. <c>dbo</c>, <c>sales</c>).</summary>
    public const string Schema = "schema";

    /// <summary>The unqualified table (or view) name the browsed column belongs to.</summary>
    public const string Table = "table";

    /// <summary>The browsed column's own name — the wide-row tag's value column.</summary>
    public const string ColumnName = "columnName";

    /// <summary>
    ///     The table's preferred date/time-typed column, when it has one: the commit writes it as the
    ///     wide-row <c>rowSelector.topByTimestamp</c>, i.e. "read the newest row". Absent when the table
    ///     carries no date/time column at all, which is not a shape a browse can bind — see
    ///     <c>RawBrowseCommitMapper.DescribeUncommittableLeaf</c>.
    /// </summary>
    public const string TopByTimestamp = "topByTimestamp";
}