lmxopcua/src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Uns/RawBrowseCommitMapper.cs

using System.Text.Json.Nodes;
using ZB.MOM.WW.OtOpcUa.AdminUI.Uns.TagEditors;
using ZB.MOM.WW.OtOpcUa.Commons.Types;
using ZB.MOM.WW.OtOpcUa.Configuration.Enums;
using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
using ZB.MOM.WW.OtOpcUa.Driver.AbCip;
using ZB.MOM.WW.OtOpcUa.Driver.FOCAS;
using ZB.MOM.WW.OtOpcUa.Driver.Sql.Contracts;
using ZB.MOM.WW.OtOpcUa.Driver.TwinCAT;
using ZB.MOM.WW.OtOpcUa.Driver.Mqtt;

namespace ZB.MOM.WW.OtOpcUa.AdminUI.Uns;

/// <summary>
/// Pure mapper for the WP6 "Browse device…" re-target: turns a selected driver-browse leaf into a
/// <see cref="RawTagImportRow"/> ready for <see cref="IRawTreeService.ImportTagsAsync"/>. Under the v3
/// identity contract the tag's identity is its RawPath (device + optional group + name), so the leaf's
/// driver reference is written into the driver-typed <c>TagConfig</c> as an ordinary <b>address field</b>
/// (<c>nodeId</c>/<c>tagPath</c>/<c>symbolPath</c>/<c>address</c>/<c>attributeRef</c> per driver) — never an
/// identity key. The address-field write reuses the same <c>&lt;Driver&gt;TagConfigModel</c> the typed tag
/// editors use, so a browse-committed tag round-trips through that editor unchanged.
/// </summary>
public static class RawBrowseCommitMapper
{
    /// <summary>
    /// Maps one selected browse leaf into an import row.
    /// </summary>
    /// <param name="driverType">The owning device's driver type (a <see cref="DriverTypeNames"/> value).</param>
    /// <param name="fullName">The leaf's driver-side full reference (the <c>BrowseNode.NodeId</c> = the
    /// captured <c>DriverAttributeInfo.FullName</c>) — becomes the driver-typed address field.</param>
    /// <param name="browseName">The leaf's browse name. Becomes the raw tag <c>Name</c> after
    /// <see cref="ToRawSegment"/> coerces it into a legal RawPath segment — a Sparkplug metric name
    /// legitimately contains <c>/</c> and a Name may not (Gitea #509). The leaf's binding address is
    /// unaffected: it travels separately into the <c>TagConfig</c>.</param>
    /// <param name="driverDataType">The leaf's <see cref="DriverDataType"/> name (from the browse
    /// attribute side-channel), or null when the browser cannot report a type (e.g. the OPC UA Client tree).</param>
    /// <param name="defaultDataType">The OPC-UA built-in type name to fall back to when
    /// <paramref name="driverDataType"/> is null/unmappable.</param>
    /// <param name="groupPrefix">The target TagGroup's device-relative path when committing under a group,
    /// or null when committing at the device root. Prepended to any mirrored folder path.</param>
    /// <param name="folderPath">The captured browse-folder nesting above the leaf (root→parent display
    /// names); mirrored onto nested TagGroups only when <paramref name="createGroups"/> is true.</param>
    /// <param name="createGroups">When true, mirror <paramref name="folderPath"/> as nested TagGroups.</param>
    /// <param name="addressFields">The leaf's structured address (<see cref="AttributeInfo.AddressFields"/>),
    /// for a driver whose binding is a tuple rather than a single reference string; null for every driver
    /// whose address is the <paramref name="fullName"/> itself.</param>
    /// <returns>The assembled import row.</returns>
    public static RawTagImportRow MapLeaf(
        string driverType,
        string fullName,
        string browseName,
        string? driverDataType,
        string defaultDataType,
        string? groupPrefix,
        IReadOnlyList<string>? folderPath,
        bool createGroups,
        IReadOnlyDictionary<string, string>? addressFields = null)
    {
        var dataType = MapDataType(driverDataType) ?? defaultDataType;
        var tagConfig = BuildTagConfig(driverType, fullName, addressFields);
        var name = ToRawSegment(browseName);
        var mirrored = createGroups && folderPath is { Count: > 0 }
            ? string.Join(RawPaths.Separator, folderPath)
            : null;
        var groupPath = CombineGroupPath(groupPrefix, mirrored);

        // Access baseline mirrors manual entry (Read); write-idempotent stays false (unknown at browse time);
        // no poll-group (batching is authored later).
        return new RawTagImportRow(
            groupPath,
            new RawTagInput(name, dataType, TagAccessLevel.Read, WriteIdempotent: false, PollGroupId: null, tagConfig));
    }

    /// <summary>
    ///     Coerces a browse leaf's name into a legal RawPath segment (Gitea #509): trims the ends and
    ///     replaces every <see cref="RawPaths.Separator"/> with <see cref="SeparatorReplacement"/>.
    /// </summary>
    /// <param name="browseName">The leaf's browse name, as the driver reported it.</param>
    /// <returns>A <see cref="RawPaths.ValidateSegment"/>-clean segment; blank only if the input was blank.</returns>
    /// <remarks>
    ///     <para>
    ///     <b>The Name and the address are two fields, and only the Name is constrained.</b> A tag Name is
    ///     a RawPath segment, so it may not contain <c>/</c>; the driver-side reference it binds by has no
    ///     such rule and is written into the <c>TagConfig</c> untouched by <see cref="BuildTagConfig"/>.
    ///     Refusing the commit outright conflated the two — and it refused a metric the Sparkplug B spec
    ///     makes <em>mandatory</em> on every edge node (<c>Node Control/Rebirth</c>), so the one metric an
    ///     operator is most likely to browse for was the one that could not be committed.
    ///     </para>
    ///     <para>
    ///     <b>This deliberately covers every driver, not just MQTT.</b> The argument is about what a Name
    ///     is, not about who produced it: any browser whose leaf name carries a <c>/</c> hits the same
    ///     wall, and for all of them the binding address travels separately and survives intact.
    ///     </para>
    ///     <para>
    ///     <b>The rule set is <see cref="RawPaths.ValidateSegment"/>'s, not an invented one</b> — empty,
    ///     an embedded separator, and leading/trailing whitespace are exactly what it rejects, so trimming
    ///     and replacing is total rather than a best-effort guess. <c>RawBrowseCommitMapperTests</c> pins
    ///     that by asserting the output validates, so a new rule there fails here instead of silently
    ///     letting an illegal Name through to the import.
    ///     </para>
    ///     <para>
    ///     Sanitising is not injective, so two distinct leaves can land on one Name — see
    ///     <see cref="DescribeNameCollisions"/>, which is why a caller must run that check rather than
    ///     trusting this in isolation.
    ///     </para>
    /// </remarks>
    public static string ToRawSegment(string? browseName)
    {
        var trimmed = (browseName ?? "").Trim();
        return trimmed.Length == 0 ? "" : trimmed.Replace(RawPaths.Separator, SeparatorReplacement);
    }

    /// <summary>What <see cref="ToRawSegment"/> substitutes for a separator inside a browse name.</summary>
    private const char SeparatorReplacement = '_';

    /// <summary>
    ///     Names the browse leaves that <see cref="ToRawSegment"/> would land on one tag Name within one
    ///     target group, or an empty list when the mapped rows are all distinct.
    /// </summary>
    /// <param name="browseNames">The ORIGINAL leaf names, in the same order as <paramref name="rows"/>.</param>
    /// <param name="rows">The mapped import rows.</param>
    /// <returns>One operator-facing message per colliding set; empty when there is nothing to refuse.</returns>
    /// <remarks>
    ///     Sanitising maps many names onto one — <c>A/B</c> and <c>A_B</c> both become <c>A_B</c> — and a
    ///     silent collision is materially worse than the refusal #509 replaced: two distinct metrics would
    ///     become one tag bound to whichever address the import happened to keep. So the coercion is only
    ///     safe when paired with this check.
    ///     <para>
    ///     Scoped per target group, because the Name only has to be unique within its group — the same
    ///     metric name under two devices is not a collision.
    ///     </para>
    ///     <para>
    ///     The message names the specific pair rather than failing the batch anonymously. The commit
    ///     itself stays all-or-nothing, matching the CSV import's staged-review semantics: nothing is
    ///     written while any row is unresolvable.
    ///     </para>
    /// </remarks>
    public static IReadOnlyList<string> DescribeNameCollisions(
        IReadOnlyList<string> browseNames,
        IReadOnlyList<RawTagImportRow> rows)
    {
        ArgumentNullException.ThrowIfNull(browseNames);
        ArgumentNullException.ThrowIfNull(rows);

        return rows
            .Select((row, i) => (row, original: i < browseNames.Count ? browseNames[i] : row.Tag.Name))
            .GroupBy(x => (x.row.TagGroupPath ?? "", x.row.Tag.Name), TupleComparer)
            .Where(g => g.Count() > 1)
            .Select(g =>
                $"'{g.Key.Item2}' would be the name of {g.Count()} different tags"
                + (string.IsNullOrEmpty(g.Key.Item1) ? "" : $" in group '{g.Key.Item1}'")
                + $": {string.Join(", ", g.Select(x => $"'{x.original}'"))}. "
                + "Their names differ only by characters that are not legal in a tag name. Commit them "
                + "separately, or author them by manual entry with distinct names.")
            .ToList();
    }

    /// <summary>Ordinal comparer for the (group path, name) collision key — RawPath comparison is ordinal.</summary>
    private static readonly IEqualityComparer<(string, string)> TupleComparer =
        EqualityComparer<(string, string)>.Create(
            (a, b) => RawPaths.Comparer.Equals(a.Item1, b.Item1) && RawPaths.Comparer.Equals(a.Item2, b.Item2),
            x => HashCode.Combine(RawPaths.Comparer.GetHashCode(x.Item1), RawPaths.Comparer.GetHashCode(x.Item2)));

    /// <summary>
    /// Maps a <see cref="DriverDataType"/> enum NAME (as reported by the browse attribute side-channel) to the
    /// OPC-UA built-in type name a <see cref="RawTagInput.DataType"/> carries. Mirrors
    /// <c>DiscoveredNodeMapper.ToBuiltinTypeString</c>: most names pass through, <c>Float32</c>/<c>Float64</c>
    /// become <c>Float</c>/<c>Double</c>, and <c>Reference</c> (a Galaxy attribute ref) carries as <c>String</c>.
    /// Returns null when the input is null/blank or not a known driver data type (caller supplies a default).
    /// </summary>
    /// <param name="driverDataType">The <see cref="DriverDataType"/> name, or null/blank.</param>
    /// <returns>The OPC-UA built-in type name, or null when unmappable.</returns>
    public static string? MapDataType(string? driverDataType)
    {
        if (string.IsNullOrWhiteSpace(driverDataType)
            || !Enum.TryParse<DriverDataType>(driverDataType, ignoreCase: true, out var dt))
            return null;

        return dt switch
        {
            DriverDataType.Boolean => "Boolean",
            DriverDataType.Int16 => "Int16",
            DriverDataType.Int32 => "Int32",
            DriverDataType.Int64 => "Int64",
            DriverDataType.UInt16 => "UInt16",
            DriverDataType.UInt32 => "UInt32",
            DriverDataType.UInt64 => "UInt64",
            DriverDataType.Float32 => "Float",
            DriverDataType.Float64 => "Double",
            DriverDataType.String => "String",
            DriverDataType.DateTime => "DateTime",
            DriverDataType.Reference => "String",
            _ => null,
        };
    }

    /// <summary>
    /// Builds the driver-typed <c>TagConfig</c> JSON for a browse-committed tag: the driver's address field
    /// from <paramref name="fullName"/>, plus — for a driver that binds by its OWN data-type enum — the
    /// native type the browse leaf stated (see <see cref="NativeType{TEnum}"/>). Every other field stays at
    /// its model default, for the operator to author afterwards. Reuses the
    /// <c>&lt;Driver&gt;TagConfigModel</c> for driver types that have a typed editor; the model-less Galaxy
    /// driver gets the canonical camelCase <c>attributeRef</c> key directly.
    /// <para>
    /// <b>The data type is not optional decoration for AB CIP / TwinCAT / FOCAS</b> — their tag-definition
    /// factories decode the wire bytes by this field, not by the raw tag row's OPC UA <c>DataType</c>. A
    /// committed leaf left at the model default therefore reads real data through the wrong decoder and
    /// publishes a plausible wrong number rather than an error (Gitea #536).
    /// </para>
    /// <para>
    /// <b>MQTT is the one driver whose address is not a single string</b> — a Sparkplug tag binds by a
    /// <c>(group, edgeNode, device?, metric)</c> tuple — so it is built from the browse session's stated
    /// <paramref name="addressFields"/> instead. See <see cref="BuildMqttTagConfig"/>.
    /// </para>
    /// </summary>
    /// <param name="driverType">The owning device's driver type.</param>
    /// <param name="fullName">The leaf's driver-side full reference to write into the address field.</param>
    /// <param name="addressFields">The leaf's structured address, when the driver binds by a tuple —
    /// see <see cref="BuildMqttTagConfig"/>. Ignored by every single-reference driver.</param>
    /// <returns>The serialised driver-typed <c>TagConfig</c> JSON.</returns>
    public static string BuildTagConfig(
        string driverType,
        string fullName,
        IReadOnlyDictionary<string, string>? addressFields = null)
    {
        var address = fullName ?? "";
        if (Is(driverType, DriverTypeNames.Mqtt))
            return BuildMqttTagConfig(address, addressFields);
        if (Is(driverType, DriverTypeNames.OpcUaClient))
            return new OpcUaClientTagConfigModel { NodeId = address }.ToJson();
        if (Is(driverType, DriverTypeNames.AbCip))
            return new AbCipTagConfigModel
            {
                TagPath = address,
                DataType = NativeType(addressFields, AbCipDataType.DInt),
            }.ToJson();
        if (Is(driverType, DriverTypeNames.AbLegacy))
            return new AbLegacyTagConfigModel { Address = address }.ToJson();
        if (Is(driverType, DriverTypeNames.TwinCAT))
            return new TwinCATTagConfigModel
            {
                SymbolPath = address,
                DataType = NativeType(addressFields, TwinCATDataType.DInt),
            }.ToJson();
        if (Is(driverType, DriverTypeNames.FOCAS))
            return new FocasTagConfigModel
            {
                Address = address,
                DataType = NativeType(addressFields, FocasDataType.Int32),
            }.ToJson();
        if (Is(driverType, DriverTypeNames.S7))
            return new S7TagConfigModel { Address = address }.ToJson();
        // MTConnect: the DataItem id. The driver also accepts "address"/"dataItemId", but the typed
        // editor's canonical spelling is fullName — committing under the generic key below would open
        // in that editor with an EMPTY id field and blank it on save.
        if (Is(driverType, DriverTypeNames.MTConnect))
            return new MTConnectTagConfigModel { FullName = address }.ToJson();
        if (Is(driverType, DriverTypeNames.Galaxy))
            return WriteSingleKey("attributeRef", address);
        // Sql: a browsed leaf is a COLUMN, and a column name alone cannot address a tag — SqlTagConfigModel
        // needs the table too. SqlBrowseSession therefore travels schema/table/columnName in AddressFields.
        // Without this branch a Sql commit fell through to the generic "address" key below, which the typed
        // Sql editor does not read: it would open with empty fields and blank them on save — the exact
        // failure the MTConnect branch above was added to avoid (deferment.md G-6). Sql IS browsable
        // (SqlDriverBrowser), so the fallback's "browsable drivers are all handled above" was untrue.
        if (Is(driverType, DriverTypeNames.Sql))
            return BuildSqlTagConfig(address, addressFields);

        // Unknown/flat-address driver (e.g. Modbus is not browsable): record the reference under a generic
        // "address" key so nothing is lost. RawBrowseCommitMapperParityTests enumerates DriverTypeNames.All
        // and holds this line to two claims rather than to the assertion the comment used to make:
        //   - a driver type with a bespoke IDriverBrowser registered by AddAdminUI() — read back from the
        //     real registration, not a list — must NOT reach here; and
        //   - any type that does reach here must be named in that test's GenericKeyExemptions with a reason,
        //     and every name on that list must still reach here (Gitea #558) — an exemption for a driver
        //     that has since gained a branch above is a stale claim, and a silently inert one.
        // The universal DiscoveryDriverBrowser's arm is not derivable from the AdminUI assembly (it needs
        // the runtime drivers + the Host's IDriverFactory), so it is covered by the exemption list rather
        // than mechanically — see the test's remarks for the residual trust that leaves (Gitea #555).
        return WriteSingleKey("address", address);
    }

    /// <summary>
    /// Builds the <c>TagConfig</c> for a browse-committed <b>MQTT</b> leaf, whose address is a
    /// <i>descriptor</i> rather than a single reference string: <c>topic</c> in Plain mode, and the
    /// <c>groupId</c>/<c>edgeNodeId</c>/<c>deviceId?</c>/<c>metricName</c> tuple in Sparkplug B mode.
    /// </summary>
    /// <param name="fullName">The leaf's browse node id — the Plain-mode fallback address only.</param>
    /// <param name="addressFields">The structured address the browse session stated.</param>
    /// <returns>The serialised <c>TagConfig</c> JSON.</returns>
    /// <remarks>
    ///     <para>
    ///     <b>The address is read from <paramref name="addressFields"/>, never parsed out of
    ///     <paramref name="fullName"/>.</b> A Sparkplug browse node id is
    ///     <c>{group}/{node}[/{device}]::{metric}</c>, and a metric name legitimately contains <c>/</c>
    ///     (<c>Node Control/Rebirth</c>) — so splitting the id cannot recover the tuple in general, and a
    ///     mapper that guessed would silently bind the wrong metric. The session that decoded the birth
    ///     already holds the decomposition and hands it over; this method only picks the keys it knows.
    ///     </para>
    ///     <para>
    ///     <b>Plain vs Sparkplug is likewise stated, not inferred</b> — the driver <i>type</i> reaching
    ///     here is just <c>Mqtt</c>, and the mode lives on the driver config, not on the tag. The
    ///     producing session knows its own mode and says so by which keys it emits: a
    ///     <c>metricName</c> ⇒ Sparkplug, a <c>topic</c> ⇒ Plain. (The blob deliberately carries no
    ///     <c>mode</c> key: <c>MqttTagDefinitionFactory</c> takes the shape from the driver's mode and
    ///     would ignore one, and <c>MqttTagConfigModel</c> re-infers it from these same keys.)
    ///     </para>
    ///     <para>
    ///     Keys are <b>whitelisted</b>, not splatted: these values came off a broker, and everything
    ///     beyond the address (payload format, JSONPath, QoS, dataType) stays at the driver's own
    ///     defaults for the operator to author afterwards. A leaf with no stated address at all is
    ///     rejected before this is reached — see <see cref="DescribeUncommittableLeaf"/>.
    ///     </para>
    /// </remarks>
    private static string BuildMqttTagConfig(string fullName, IReadOnlyDictionary<string, string>? addressFields)
    {
        if (TryGetField(addressFields, MqttTagConfigKeys.MetricName) is { } metricName)
        {
            var o = new JsonObject
            {
                [MqttTagConfigKeys.GroupId] = TryGetField(addressFields, MqttTagConfigKeys.GroupId) ?? "",
                [MqttTagConfigKeys.EdgeNodeId] = TryGetField(addressFields, MqttTagConfigKeys.EdgeNodeId) ?? "",
                [MqttTagConfigKeys.MetricName] = metricName,
            };

            // Absent, not blank, for a node-level metric — the two describe the same scope to the
            // factory, but only the absent form says "this metric has no device" to a reader.
            if (TryGetField(addressFields, MqttTagConfigKeys.DeviceId) is { } deviceId)
                o[MqttTagConfigKeys.DeviceId] = deviceId;

            return o.ToJsonString();
        }

        // Plain: the session states the topic; the node id is the same value and is the fallback for a
        // session that stated nothing (a shape DescribeUncommittableLeaf refuses upstream).
        return WriteSingleKey(
            MqttTagConfigKeys.Topic,
            TryGetField(addressFields, MqttTagConfigKeys.Topic) ?? fullName);
    }

    /// <summary>
    /// Describes why a selected browse leaf cannot be committed as a working tag, or <c>null</c> when it
    /// can. The AdminUI calls this before mapping so an unbindable selection fails <b>at commit, in
    /// words</b>.
    /// </summary>
    /// <param name="driverType">The owning device's driver type.</param>
    /// <param name="browseName">The leaf's browse name, for the message.</param>
    /// <param name="addressFields">The structured address the browse session stated, if any.</param>
    /// <returns>The operator-facing reason, or <c>null</c> when the leaf is committable.</returns>
    /// <remarks>
    ///     <para>
    ///     Exactly two drivers can fail this, and both for the same underlying reason: their binding is a
    ///     TUPLE, so a leaf can be selectable in the tree and still not carry enough to bind. Every
    ///     single-reference driver is unaffected — its address IS the node id.
    ///     </para>
    ///     <para>
    ///     <b>MQTT</b>: a leaf whose attribute lookup returned nothing, so no address was stated. Committing
    ///     it anyway is the defect this whole seam exists to close — a Sparkplug tuple cannot be
    ///     reconstructed from the node id, so the row would deploy clean and then report
    ///     <c>BadNodeIdUnknown</c> forever with nothing to point at.
    ///     </para>
    ///     <para>
    ///     <b>Sql</b> (Gitea #552): a column of a table carrying no date/time column. A wide-row tag must say
    ///     which ROW it reads, and with no timestamp to order by the only remaining selector is a
    ///     <c>whereColumn</c>/<c>whereValue</c> pair — whose value is <em>data</em>, not schema, and therefore
    ///     is not something any browse can know. Refusing here rather than letting the import's own gate
    ///     refuse the blob is what makes the message name the table and the fix; the gate would only report
    ///     that a row selector is missing, on every selected column at once.
    ///     </para>
    /// </remarks>
    public static string? DescribeUncommittableLeaf(
        string driverType,
        string browseName,
        IReadOnlyDictionary<string, string>? addressFields)
    {
        if (Is(driverType, DriverTypeNames.Mqtt)) return DescribeUncommittableMqttLeaf(browseName, addressFields);
        if (Is(driverType, DriverTypeNames.Sql)) return DescribeUncommittableSqlLeaf(browseName, addressFields);
        return null;
    }

    /// <summary>Describes an MQTT leaf that states no address at all, or <c>null</c> when it states one.</summary>
    /// <param name="browseName">The leaf's browse name, for the message.</param>
    /// <param name="addressFields">The structured address the browse session stated, if any.</param>
    /// <returns>The operator-facing reason, or <c>null</c>.</returns>
    private static string? DescribeUncommittableMqttLeaf(
        string browseName, IReadOnlyDictionary<string, string>? addressFields)
    {
        if (TryGetField(addressFields, MqttTagConfigKeys.MetricName) is not null) return null;
        if (TryGetField(addressFields, MqttTagConfigKeys.Topic) is not null) return null;

        return $"'{browseName}' could not be committed: the browse session reported no MQTT address for it "
             + "(its attribute lookup returned nothing). Re-open the browser and re-select it, or author "
             + "the tag manually.";
    }

    /// <summary>
    ///     Describes a Sql column leaf whose wide-row binding cannot be completed from the catalog, or
    ///     <c>null</c> when it can (Gitea #552).
    /// </summary>
    /// <param name="browseName">The leaf's browse name, for the message.</param>
    /// <param name="addressFields">The structured address the browse session stated, if any.</param>
    /// <returns>The operator-facing reason, or <c>null</c>.</returns>
    private static string? DescribeUncommittableSqlLeaf(
        string browseName, IReadOnlyDictionary<string, string>? addressFields)
    {
        if (TryGetField(addressFields, SqlBrowseAddressFields.Table) is not { } table)
        {
            return $"'{browseName}' could not be committed: the browse session reported no Sql table for it "
                 + "(its attribute lookup returned nothing). Re-open the browser and re-select it, or author "
                 + "the tag manually.";
        }

        if (TryGetField(addressFields, SqlBrowseAddressFields.TopByTimestamp) is not null) return null;

        return $"'{browseName}' could not be committed: '{table}' has no date/time column, so which ROW the "
             + "tag reads cannot be derived from the schema. Author it in the tag editor with a "
             + "whereColumn/whereValue row selector — the value it matches on is data, not schema, so the "
             + "browser cannot supply it.";
    }

    /// <summary>
    ///     Reads the browse leaf's driver-native data type out of the stated address fields, falling
    ///     back to <paramref name="fallback"/> — the driver model's own default — when the browser
    ///     stated none or stated one this driver's enum does not name.
    /// </summary>
    /// <typeparam name="TEnum">The driver's own data-type enum.</typeparam>
    /// <param name="addressFields">The leaf's stated address fields.</param>
    /// <param name="fallback">The model default to keep when no usable native type was stated.</param>
    /// <returns>The parsed native type, or <paramref name="fallback"/>.</returns>
    /// <remarks>
    ///     <b>The type is READ, never derived (Gitea #536).</b> A commit used to leave this at the
    ///     model default, so every browsed AB CIP leaf — a REAL, a BOOL, a STRING — was written as
    ///     <c>DInt</c> and the driver decoded four bytes of a float as an integer: a plausible
    ///     number, no error, wrong value. Deriving it from the leaf's driver-AGNOSTIC
    ///     <c>DriverDataType</c> instead would fix the REAL and still get the integers wrong —
    ///     <c>SInt</c>, <c>Int</c> and <c>DInt</c> all collapse into <c>Int32</c> on the way out, so
    ///     a 16-bit INT would come back as a 32-bit DINT. The producing driver knows its own type
    ///     and states it; see <c>CapturedTreeBrowseSession.NativeTypeFields</c>.
    ///     <para>
    ///     Case-insensitive because the key travels as an enum NAME, and a driver is free to spell
    ///     it however its own enum does. An unparseable value keeps the default rather than failing
    ///     the commit: the address — the part that cannot be re-derived later — is still correct,
    ///     and the operator can fix the type in the typed editor.
    ///     </para>
    ///     <para>
    ///     <b>A numeric string is refused before parsing.</b> <c>Enum.TryParse</c> accepts <c>"9"</c>
    ///     for any enum and hands back whatever member sits at ordinal 9 — which <c>Enum.IsDefined</c>
    ///     then happily confirms — so a driver that stamped a number would bind a tag to a type nobody
    ///     named. Same trap <c>MTConnectTagConfigModel</c> documents for its own <c>dataType</c>.
    ///     </para>
    /// </remarks>
    private static TEnum NativeType<TEnum>(IReadOnlyDictionary<string, string>? addressFields, TEnum fallback)
        where TEnum : struct, Enum
        => TryGetField(addressFields, "dataType") is { Length: > 0 } raw
           && !char.IsAsciiDigit(raw[0]) && raw[0] is not ('-' or '+')
           && Enum.TryParse<TEnum>(raw, ignoreCase: true, out var parsed)
           && Enum.IsDefined(parsed)
            ? parsed
            : fallback;

    /// <summary>Reads one non-blank address field, or <c>null</c> when it is absent or blank.</summary>
    /// <param name="fields">The stated address fields, or null.</param>
    /// <param name="key">The field to read.</param>
    /// <returns>The trimmed value, or <c>null</c>.</returns>
    private static string? TryGetField(IReadOnlyDictionary<string, string>? fields, string key)
        => fields is not null && fields.TryGetValue(key, out var v) && !string.IsNullOrWhiteSpace(v)
            ? v.Trim()
            : null;

    /// <summary>
    /// Combines a target-group path prefix with an optional mirrored sub-path, matching the WP5 CSV import
    /// combine semantics: blank collapses to null, and a present prefix + suffix join with the RawPath
    /// separator. Returns null when both are absent (⇒ commit at the device root).
    /// </summary>
    /// <param name="prefix">The target TagGroup's device-relative path, or null/blank for the device root.</param>
    /// <param name="suffix">The mirrored folder sub-path, or null/blank.</param>
    /// <returns>The combined device-relative group path, or null for the device root.</returns>
    public static string? CombineGroupPath(string? prefix, string? suffix)
    {
        prefix = string.IsNullOrWhiteSpace(prefix) ? null : prefix.Trim();
        suffix = string.IsNullOrWhiteSpace(suffix) ? null : suffix.Trim();
        if (prefix is null) return suffix;
        return suffix is null ? prefix : $"{prefix}{RawPaths.SeparatorString}{suffix}";
    }

    private static bool Is(string driverType, string name)
        => string.Equals(driverType, name, StringComparison.OrdinalIgnoreCase);

    /// <summary>
    ///     Builds a <c>SqlTagConfigModel</c> blob from a browsed COLUMN leaf. Maps to
    ///     <c>SqlTagModel.WideRow</c> — the browse tree is schema → table → column, which is precisely the
    ///     wide-row shape (one row holds many signals as columns). A KeyValue (EAV) tag cannot be derived
    ///     from a browse pick because its key VALUE is data, not schema, so the operator authors that in the
    ///     typed editor.
    ///     <para>Falls back to the generic key when the fields are absent — an older browser build, or a
    ///     hand-made selection — rather than emitting a half-built Sql blob.</para>
    /// </summary>
    /// <param name="address">The leaf's browse node id — the column-name fallback only.</param>
    /// <param name="addressFields">The structured address the browse session stated.</param>
    /// <returns>The serialised <c>TagConfig</c> JSON.</returns>
    /// <remarks>
    ///     <para>
    ///     <b>A wide-row tag needs three things, not two: the table, the column, and WHICH ROW</b>
    ///     (Gitea #552). This branch used to emit only the first two, and a selector-less wide-row blob is
    ///     refused by <c>SqlEquipmentTagParser</c> and by <c>SqlTagConfigModel.Validate</c> alike — so every
    ///     browse-committed Sql tag was unreadable, first silently (<c>BadNodeIdUnknown</c> forever) and then,
    ///     once #551 put the gate on the import, loudly at commit.
    ///     </para>
    ///     <para>
    ///     <b>The row selector is READ from the session's stated fields, never inferred here</b> — same rule
    ///     as MQTT's Sparkplug tuple. The session holds the table's column metadata and names a date/time
    ///     column by TYPE (see <c>SqlBrowseSession.PreferredTimestampColumn</c>); this mapper has only a
    ///     column name and a table name, from which any selector it invented would be a guess about data.
    ///     </para>
    ///     <para>
    ///     <b>When no candidate was stated the blob stays selector-less on purpose.</b> The alternatives are
    ///     worse: a fabricated selector binds the tag to a row nobody chose, and dropping to the generic
    ///     <c>{"address": …}</c> key throws away the table the session did know. Kept in the wide-row shape,
    ///     the blob opens in the typed editor with everything but the selector filled in — and the commit
    ///     itself does not reach here, because <see cref="DescribeUncommittableLeaf"/> refuses that leaf in
    ///     words first.
    ///     </para>
    ///     <para>
    ///     The blob's top-level <c>timestampColumn</c> (the SOURCE-timestamp column, which makes the driver
    ///     stamp values with the row's time instead of the poll time) is deliberately left unset: ordering by
    ///     a column is not a claim that it timestamps the value, and turning it on silently would change every
    ///     browse-committed tag's published SourceTimestamp.
    ///     </para>
    /// </remarks>
    private static string BuildSqlTagConfig(string address, IReadOnlyDictionary<string, string>? addressFields)
    {
        if (addressFields is null
            || !addressFields.TryGetValue(SqlBrowseAddressFields.Table, out var table)
            || string.IsNullOrWhiteSpace(table))
        {
            return WriteSingleKey("address", address);
        }

        addressFields.TryGetValue(SqlBrowseAddressFields.Schema, out var schema);
        addressFields.TryGetValue(SqlBrowseAddressFields.ColumnName, out var columnName);

        // Qualify the table with its schema when the schema is not the default, so a tag authored against
        // "sales.Readings" cannot silently resolve to "dbo.Readings".
        var qualified = !string.IsNullOrWhiteSpace(schema) && !string.Equals(schema, "dbo", StringComparison.OrdinalIgnoreCase)
            ? $"{schema}.{table}"
            : table;

        return new SqlTagConfigModel
        {
            Model = SqlTagModel.WideRow,
            Table = qualified,
            ColumnName = string.IsNullOrWhiteSpace(columnName) ? address : columnName,

            // Null when the session stated none: SqlRowSelectorModel.ToJsonObject then returns null and the
            // "rowSelector" key is omitted entirely, rather than written as an empty or blank-valued object.
            RowSelector = new SqlRowSelectorModel
            {
                TopByTimestamp = TryGetField(addressFields, SqlBrowseAddressFields.TopByTimestamp),
            },
        }.ToJson();
    }

    private static string WriteSingleKey(string key, string value)
    {
        var o = new JsonObject { [key] = value };
        return o.ToJsonString();
    }
}