FOCAS PR 1 — Scaffolding + Core (FocasDriver skeleton + address parser + stub client). New Driver.FOCAS project for Fanuc CNC controllers (FS 0i/16i/18i/21i/30i/31i/32i/Series 35i/Power Mate i) talking via the Fanuc FOCAS/2 protocol. No NuGet reference to a FOCAS library — FWLIB (Fwlib32.dll) is Fanuc-proprietary + per-customer licensed + cannot be legally redistributed, so the driver is designed from the start to accept an IFocasClient supplied by the deployment side. Default IFocasClientFactory is UnimplementedFocasClientFactory which throws with a clear deployment-docs pointer at Create time so misconfigured servers fail fast rather than mysteriously hanging. Matches the pattern other drivers use for swappable wire layers (Modbus IModbusTransport, AbCip IAbCipTagFactory, TwinCAT ITwinCATClientFactory) — but uniquely, FOCAS ships without a production factory because of licensing. FocasHostAddress parses focas://{host}[:{port}] canonical form with default port 8193 (Fanuc-reserved FOCAS Ethernet port). Default-port stripping on ToString for roundtrip stability. Case-insensitive scheme. Rejects wrong scheme, empty body, invalid port, non-numeric port. FocasAddress handles the three addressing spaces a FOCAS driver touches — PMC (letter + byte + optional bit, X/Y for IO, F/G for PMC-CNC signals, R for internal relay, D for data table, C for counter, K for keep relay, A for message display, E for extended relay, T for timer, with .N bit syntax 0-7), CNC parameters (PARAM:n for a parameter number, PARAM:n/N for bit 0-31 of a parameter), macro variables (MACRO:n). Rejects unknown PMC letters, negative numbers, out-of-range bits (PMC 0-7, parameter 0-31), non-numeric fragments. FocasDataType — Bit / Byte / Int16 / Int32 / Float32 / Float64 / String covering the atomic types PMC reads + CNC parameters + macro variables return. ToDriverDataType widens to the Int32/Float32/Float64/Boolean/String surface. FocasStatusMapper covers the FWLIB EW_* return-code family documented in the FOCAS/1 + FOCAS/2 references — EW_OK=0, EW_FUNC=1 → BadNotSupported, EW_OVRFLOW=2/EW_NUMBER=3/EW_LENGTH=4 → BadOutOfRange, EW_PROT=5/EW_PASSWD=11 → BadNotWritable, EW_NOOPT=6/EW_VERSION=-9 → BadNotSupported, EW_ATTRIB=7 → BadTypeMismatch, EW_DATA=8 → BadNodeIdUnknown, EW_PARITY=9 → BadCommunicationError, EW_BUSY=-1 → BadDeviceFailure, EW_HANDLE=-8 → BadInternalError, EW_UNEXP=-10/EW_SOCKET=-16 → BadCommunicationError. IFocasClient + IFocasClientFactory abstraction — ConnectAsync, IsConnected, ReadAsync returning (value, status) tuple, WriteAsync returning status, ProbeAsync for IHostConnectivityProbe. Deployment supplies the real factory; driver assembly stays licence-clean. FocasDriverOptions + FocasDeviceOptions + FocasTagDefinition + FocasProbeOptions — one instance supports N CNCs, tags cross-key by HostAddress + use canonical FocasAddress strings. FocasDriver implements IDriver only (PRs 2-3 add read/write/discover/subscribe/probe/resolver). InitializeAsync parses each device HostAddress + fails fast on malformed strings → Faulted health. 65 new unit tests in FocasScaffoldingTests covering — 5 valid host forms + 8 invalid + default-port-strip ToString, 12 valid PMC addresses across all 11 canonical letters + 3 parameter forms with + without bit + 2 macro forms, 10 invalid address shapes, canonical roundtrip theory, data-type mapping theory, FWLIB EW_* status mapping theory (9 codes + unknown → generic), DriverType, multi-device Initialize + address parsing, malformed-address fault, shutdown, default factory throws NotSupportedException with deployment pointer + Fwlib32.dll mention. Total project count 31 src + 20 tests; full solution builds 0 errors. Other drivers untouched.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/ZB.MOM.WW.OtOpcUa.Driver.FOCAS/FocasDriver.cs

@@ -0,0 +1,89 @@
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.FOCAS;
+
+/// <summary>
+///     FOCAS driver for Fanuc CNC controllers (FS 0i / 16i / 18i / 21i / 30i / 31i / 32i / Series
+///     35i / Power Mate i). Talks to the CNC via the Fanuc FOCAS/2 FWLIB protocol through an
+///     <see cref="IFocasClient"/> the deployment supplies — FWLIB itself is Fanuc-proprietary
+///     and cannot be redistributed.
+/// </summary>
+/// <remarks>
+///     PR 1 ships <see cref="IDriver"/> only; read / write / discover / subscribe / probe / host-
+///     resolver capabilities land in PRs 2 and 3. The <see cref="IFocasClient"/> abstraction
+///     shipped here lets PR 2 onward stay license-clean — all tests run against a fake client
+///     + the default <see cref="UnimplementedFocasClientFactory"/> makes misconfigured servers
+///     fail fast.
+/// </remarks>
+public sealed class FocasDriver : IDriver, IDisposable, IAsyncDisposable
+{
+    private readonly FocasDriverOptions _options;
+    private readonly string _driverInstanceId;
+    private readonly IFocasClientFactory _clientFactory;
+    private readonly Dictionary<string, DeviceState> _devices = new(StringComparer.OrdinalIgnoreCase);
+    private DriverHealth _health = new(DriverState.Unknown, null, null);
+
+    public FocasDriver(FocasDriverOptions options, string driverInstanceId,
+        IFocasClientFactory? clientFactory = null)
+    {
+        ArgumentNullException.ThrowIfNull(options);
+        _options = options;
+        _driverInstanceId = driverInstanceId;
+        _clientFactory = clientFactory ?? new UnimplementedFocasClientFactory();
+    }
+
+    public string DriverInstanceId => _driverInstanceId;
+    public string DriverType => "FOCAS";
+
+    public Task InitializeAsync(string driverConfigJson, CancellationToken cancellationToken)
+    {
+        _health = new DriverHealth(DriverState.Initializing, null, null);
+        try
+        {
+            foreach (var device in _options.Devices)
+            {
+                var addr = FocasHostAddress.TryParse(device.HostAddress)
+                    ?? throw new InvalidOperationException(
+                        $"FOCAS device has invalid HostAddress '{device.HostAddress}' — expected 'focas://{{ip}}[:{{port}}]'.");
+                _devices[device.HostAddress] = new DeviceState(addr, device);
+            }
+            _health = new DriverHealth(DriverState.Healthy, DateTime.UtcNow, null);
+        }
+        catch (Exception ex)
+        {
+            _health = new DriverHealth(DriverState.Faulted, null, ex.Message);
+            throw;
+        }
+        return Task.CompletedTask;
+    }
+
+    public async Task ReinitializeAsync(string driverConfigJson, CancellationToken cancellationToken)
+    {
+        await ShutdownAsync(cancellationToken).ConfigureAwait(false);
+        await InitializeAsync(driverConfigJson, cancellationToken).ConfigureAwait(false);
+    }
+
+    public Task ShutdownAsync(CancellationToken cancellationToken)
+    {
+        _devices.Clear();
+        _health = new DriverHealth(DriverState.Unknown, _health.LastSuccessfulRead, null);
+        return Task.CompletedTask;
+    }
+
+    public DriverHealth GetHealth() => _health;
+    public long GetMemoryFootprint() => 0;
+    public Task FlushOptionalCachesAsync(CancellationToken cancellationToken) => Task.CompletedTask;
+
+    internal int DeviceCount => _devices.Count;
+    internal DeviceState? GetDeviceState(string hostAddress) =>
+        _devices.TryGetValue(hostAddress, out var s) ? s : null;
+
+    public void Dispose() => DisposeAsync().AsTask().GetAwaiter().GetResult();
+    public async ValueTask DisposeAsync() => await ShutdownAsync(CancellationToken.None).ConfigureAwait(false);
+
+    internal sealed class DeviceState(FocasHostAddress parsedAddress, FocasDeviceOptions options)
+    {
+        public FocasHostAddress ParsedAddress { get; } = parsedAddress;
+        public FocasDeviceOptions Options { get; } = options;
+    }
+}