# Galaxy Phase C — Server-side HistoryRead — Implementation Plan

> **For Claude:** REQUIRED SUB-SKILL: use superpowers-extended-cc:subagent-driven-development (or executing-plans) to implement this plan task-by-task.

**Goal:** Answer OPC UA HistoryRead (Raw / Processed / AtTime / Events) for historized equipment
tags by dispatching to the existing `IHistorianDataSource` (Wonderware TCP client). Authoring via a
`"isHistorized"` flag in the existing `TagConfig` blob — **no UI, no EF migration**.

**Architecture:** Carry `isHistorized`/`historianTagname` through the Phase-B `alarm`-object seam
(`TagConfig` → `EquipmentTagPlan` → byte-parity artifact → `EnsureVariable`), set `Historizing` +
`AccessLevels.HistoryRead`, register a NodeId→tagname map, and override `CustomNodeManager2`'s
HistoryRead surface to block-bridge onto the async data source. Config-gated DI mirrors
`AddAlarmHistorian`; the Host supplies the Wonderware client.

**Tech Stack:** .NET 10, OPC Foundation `Opc.Ua.Server` (`CustomNodeManager2`), Akka-free node
manager, xUnit + Shouldly.

**Design:** `docs/plans/2026-06-14-galaxy-phase-c-historian-design.md` (read for the locked decisions).

---

## Execution notes (hard rules — every task)

- **Branch:** `feat/galaxy-phase-c-historian` (already created off master `c9a0f627`). Do NOT work on
  master.
- **Stage by path; never `git add .`.** Never stage `sql_login.txt`,
  `src/Server/ZB.MOM.WW.OtOpcUa.Host/pki/`, `pending.md`, `current.md`, or
  `docker-dev/docker-compose.yml`. Never echo the gateway API key or historian `SharedSecret` into a
  tracked file. No force-push, no `--no-verify`.
- **NO EF/Configuration entity or migration change.** The flag rides in `TagConfig` JSON.
- **NO bUnit** — there is no UI in Phase C; everything here is offline-unit-testable. The live `/run`
  is deferred (Task 7).
- Production projects are `TreatWarningsAsErrors` — keep the build at **0 warnings** in `src/`.
- Each task: write the failing test, see it fail, implement minimally, see it pass, then commit by path.

---

### Task 0: Feature branch (already created)

**Classification:** trivial · **Estimated implement time:** ~0 min · **Parallelizable with:** none

Precondition met — `feat/galaxy-phase-c-historian` exists off master `c9a0f627`, design committed
`5e42c1bc`. No action.

---

### Task 1: Carry `isHistorized` + `historianTagname` (composer + artifact, byte-parity)

**Classification:** standard · **Estimated implement time:** ~5 min · **Parallelizable with:** none

Mirror the Phase B `alarm`-object carrier exactly.

**Files:**
- Modify: `src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/Phase7Composer.cs`
  - `EquipmentTagPlan` record (`:82-91`): add `bool IsHistorized` and `string? HistorianTagname` as
    the last two positional fields (update the doc-comment to mention they parse identically on the
    artifact side, like `Alarm`).
  - Add `internal static (bool IsHistorized, string? HistorianTagname) ExtractTagHistorize(string?
    tagConfig)` next to `ExtractTagAlarm` (`:461`): parse `isHistorized` (bool; absent/non-bool ⇒
    false) and `historianTagname` (string; absent/blank/non-string ⇒ null). Never throws (catch
    `JsonException` ⇒ `(false, null)`). Carry the **byte-parity** comment naming
    `DeploymentArtifact.ExtractTagHistorize`.
  - In the `equipmentTags` `.Select(...)` (`:331-340`): set `IsHistorized` / `HistorianTagname` from
    `ExtractTagHistorize(t.TagConfig)`.
- Modify: `src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Drivers/DeploymentArtifact.cs`
  - Add a **byte-parity** `private static (bool, string?) ExtractTagHistorize(string? tagConfig)` next
    to `ExtractTagAlarm` (`:658`), same parse, carrying the byte-parity comment naming the composer.
  - In `BuildEquipmentTagPlans` (`:440-449`): thread the two new fields onto the `new
    EquipmentTagPlan(...)`.
- Test: `tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/ExtractTagHistorizeTests.cs` (new; model on
  `ExtractTagAlarmTests.cs`).
- Test: `tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Drivers/DeploymentArtifactHistorizeParityTests.cs`
  (new; model on `DeploymentArtifactAliasParityTests.cs`).

**Steps:**
1. Failing test `ExtractTagHistorizeTests`: `{"FullName":"T.A","isHistorized":true}` ⇒ `(true,null)`;
   `+"historianTagname":"WW.Tag"` ⇒ `(true,"WW.Tag")`; absent ⇒ `(false,null)`; `"isHistorized":false`
   ⇒ `(false,null)`; malformed JSON / blank-tagname ⇒ `(false,null)` / `(true,null)`; never throws.
2. Run → fail (method missing). Implement `ExtractTagHistorize` + record fields + Select wiring. Run →
   pass.
3. Failing test `DeploymentArtifactHistorizeParityTests`: build a snapshot with a historized tag (and
   one with an override tagname), run it through `ConfigComposer`→artifact→`DeploymentArtifact`
   decode, and assert the decoded `EquipmentTagPlan.IsHistorized`/`HistorianTagname` equal the
   composer's for the same input (parity). Run → fail. Implement the artifact side. Run → pass.
4. `dotnet build` clean (0 warn); `dotnet test` the two projects green. Commit by path
   (`Phase7Composer.cs`, `DeploymentArtifact.cs`, the two new test files).

---

### Task 2: Materialize historized — `Historizing` + `HistoryRead` bit + NodeId→tagname registry

**Classification:** standard · **Estimated implement time:** ~5 min · **Parallelizable with:** none

**Files:**
- Modify: `src/Core/ZB.MOM.WW.OtOpcUa.Commons/OpcUa/IOpcUaAddressSpaceSink.cs` — `EnsureVariable`
  signature gains a trailing `string? historianTagname` param (doc: null ⇒ not historized). Update the
  `NullOpcUaAddressSpaceSink` no-op impl in the same file.
- Modify: `src/Core/ZB.MOM.WW.OtOpcUa.Commons/OpcUa/DeferredAddressSpaceSink.cs` — pass the new param
  through.
- Modify: `src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/SdkAddressSpaceSink.cs` — pass-through.
- Modify: `src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/Phase7Applier.cs` — `SafeEnsureVariable` (`:294`)
  gains the param; `MaterialiseEquipmentTags` (`:200`) computes
  `string? historianTagname = tag.IsHistorized ? (string.IsNullOrWhiteSpace(tag.HistorianTagname) ?
  tag.FullName : tag.HistorianTagname) : null;` and passes it.
- Modify: `src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OtOpcUaNodeManager.cs`
  - Add `private readonly ConcurrentDictionary<string,string> _historizedTagnames = new(StringComparer.Ordinal);`
  - `EnsureVariable` (`:820`): take `string? historianTagname`; when non-null set `Historizing = true`,
    OR `AccessLevels.HistoryRead` into both `AccessLevel`+`UserAccessLevel` (keep the writable
    ReadWrite composite), and `_historizedTagnames[variableNodeId] = historianTagname`. When null,
    behavior is exactly as today (`Historizing=false`).
  - `RebuildAddressSpace` (`:889`): `_historizedTagnames.Clear();` alongside the other clears.
- Test: `tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/SdkAddressSpaceSinkTests.cs` (extend) — or a
  new `NodeManagerHistorizeTests.cs` if cleaner. Reuse the node-manager harness in `SdkAddressSpaceSinkTests`
  / `EquipmentWriteGateTests`.

**Steps:**
1. Failing test: materialize a variable with `historianTagname:"WW.Tag"` ⇒ the node's `Historizing`
   is true and `(AccessLevel & AccessLevels.HistoryRead) != 0`; a null tagname ⇒ `Historizing` false,
   no History bit. (Expose a read path: the existing tests already reach `BaseDataVariableState` via
   the node manager — assert on that, or add a small `TryGetVariable` test accessor if none exists.)
2. Run → fail. Thread the param through all five seam files + node manager. Run → pass.
3. Failing test (applier): a historized `EquipmentTagPlan` with no override ⇒ the sink receives
   `historianTagname == FullName`; with an override ⇒ receives the override. (Use a recording fake
   `IOpcUaAddressSpaceSink`.) Run → fail → implement the applier resolve → pass.
4. Build clean; the `OpcUaServer.Tests` suite green (existing `EnsureVariable` callers updated for the
   new param). Commit by path.

---

### Task 3: HistoryRead override — Raw / Processed / AtTime + `NullHistorianDataSource` + wiring prop

**Classification:** high-risk · **Estimated implement time:** ~6 min · **Parallelizable with:** none

This is the load-bearing OPC UA service-level task.

**Files:**
- Create: `src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/Historian/NullHistorianDataSource.cs` —
  singleton `Instance`; all reads return empty `HistoryReadResult`/`HistoricalEventsResult` (empty
  list, null continuation); `GetHealthSnapshot()` returns a disabled snapshot; `Dispose()` no-op.
- Modify: `src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OtOpcUaNodeManager.cs`
  - Add `private volatile IHistorianDataSource _historianDataSource = NullHistorianDataSource.Instance;`
    + `public IHistorianDataSource HistorianDataSource { get => _historianDataSource; set =>
    _historianDataSource = value ?? NullHistorianDataSource.Instance; }` (doc mirrors `NodeWriteGateway`).
  - **Confirm the override surface** of the installed `OPCFoundation.NetStandard.Opc.Ua.Server` first:
    query the DeepWiki MCP (`OPCFoundation/UA-.NETStandard`, per CLAUDE.md) AND inspect the actual
    base members (e.g. `grep`/decompile the referenced `Opc.Ua.Server.CustomNodeManager2` for
    `HistoryRead`). RECOMMENDED: override the per-details protected virtuals
    (`HistoryReadRawModified`, `HistoryReadProcessed`, `HistoryReadAtTime`); FALLBACK: override the
    single public `HistoryRead(...)` and switch on `details`. Whatever the chosen surface, do **not**
    invoke base for nodes we own (`_historizedTagnames` hit); mark `Processed`/fill `results[i]`.
  - Per node: resolve `NodeId.Identifier` (string) in `_historizedTagnames`; miss ⇒
    `BadHistoryOperationUnsupported`. On hit, dispatch to `_historianDataSource` (block with
    `.GetAwaiter().GetResult()` in `try`/`catch` → per-node `BadHistoryOperationUnsupported`/
    `BadUnexpectedError` + log; never fault the batch). Map `DataValueSnapshot` →
    `Opc.Ua.DataValue`; wrap in `HistoryData`; `results[i].HistoryData = new ExtensionObject(data)`;
    `StatusCode = samples.Count == 0 ? GoodNoData : Good`; `ContinuationPoint = null`. Handle
    `releaseContinuationPoints == true` ⇒ `Good` no-op.
  - `MapAggregate(NodeId)` helper → `HistoryAggregateType`; unknown ⇒ `BadAggregateNotSupported`.
  - `DataValueSnapshot→DataValue` mapping helper (value Variant, StatusCode, source+server ts).
- Test: `tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/NodeManagerHistoryReadTests.cs` (new) — a
  recording/fake `IHistorianDataSource`.
- Test: `tests/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions.Tests/Historian/NullHistorianDataSourceTests.cs`
  (new).

**Steps:**
1. Confirm the override surface (DeepWiki + assembly). Write `NullHistorianDataSource` + its test
   (empty results). Run → pass.
2. Failing test (Raw): materialize a historized node; set a fake source returning 2 samples; invoke
   the HistoryRead override with a `ReadRawModifiedDetails` + one `HistoryReadValueId` for the node;
   assert the fake got `(tagname == FullName, start, end, numValues)`, the result decodes to a
   `HistoryData` of 2 `DataValue`s with mapped value/status/timestamps, `StatusCode == Good`.
3. Run → fail. Add the prop + override + Raw path + mappers. Run → pass.
4. Add tests + impl for: Processed (aggregate mapping, `BadAggregateNotSupported` on unknown), AtTime
   (request times passed through), default-vs-override tagname, empty ⇒ `GoodNoData`, non-historized
   node ⇒ `BadHistoryOperationUnsupported`, backend-throw ⇒ per-node bad + batch survives.
5. Build clean; `OpcUaServer.Tests` + `Core.Abstractions.Tests` green. Commit by path.

---

### Task 4: HistoryRead override — Events over equipment-folder notifiers

**Classification:** high-risk · **Estimated implement time:** ~6 min · **Parallelizable with:** Task 5

**Files:**
- Modify: `src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OtOpcUaNodeManager.cs`
  - Add `private readonly ConcurrentDictionary<string,string> _eventNotifierSources = new(StringComparer.Ordinal);`
  - `EnsureFolderIsEventNotifier` (`:749`): when `_historianDataSource is not NullHistorianDataSource`,
    OR `EventNotifiers.HistoryRead` into `folder.EventNotifier` (keep `SubscribeToEvents`); register
    `_eventNotifierSources[folder.NodeId.Identifier?.ToString()] = folder.NodeId.Identifier?.ToString()`
    (the equipment id = `sourceName`). (Reads the data-source field — fine; it's set before
    materialization in the Host. If a deployment materializes before wiring, the bit is simply absent
    until the next rebuild — acceptable; document it.)
  - `RebuildAddressSpace`: `_eventNotifierSources.Clear();`.
  - Events dispatch (the `ReadEventDetails` arm of the chosen override surface): resolve the target
    folder NodeId in `_eventNotifierSources` (miss ⇒ `BadHistoryOperationUnsupported`); call
    `_historianDataSource.ReadEventsAsync(sourceName, start, end, maxEvents, ct)` (block + guard);
    project each `HistoricalEvent` → `HistoryEventFieldList` per `ReadEventDetails.Filter.SelectClauses`
    — support `BaseEventType` operands `EventId`, `SourceName`, `Time`, `Message`, `Severity`; an
    unsupported operand ⇒ `null` field; wrap in `HistoryEvent { Events = … }`; `StatusCode = Good`
    (or `GoodNoData` when empty).
  - `ProjectEventField(HistoricalEvent, SimpleAttributeOperand)` helper.
- Test: extend `NodeManagerHistoryReadTests.cs` — events arm.

**Steps:**
1. Failing test: promote a folder to a notifier with a wired (fake non-Null) source; invoke the
   override with a `ReadEventDetails` (a select clause for EventId/SourceName/Time/Message/Severity)
   on the folder; assert the fake got `(sourceName == equipmentId, …)` and each returned
   `HistoryEventFieldList` carries the projected fields in select-clause order; an unsupported operand
   ⇒ null field; empty ⇒ `GoodNoData`; a non-notifier node ⇒ `BadHistoryOperationUnsupported`.
2. Run → fail. Implement the `_eventNotifierSources` map + folder-promotion bit + the events arm +
   projector. Run → pass.
3. Build clean; `OpcUaServer.Tests` green. Commit by path.

---

### Task 5: DI + config + Host wiring (`AddServerHistorian`, `SetHistorianDataSource`)

**Classification:** standard · **Estimated implement time:** ~5 min · **Parallelizable with:** Task 4

**Files:**
- Create: `src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Historian/ServerHistorianOptions.cs` — `SectionName =
  "ServerHistorian"`; `Enabled`, `Host`, `Port`, `UseTls`, `ServerCertThumbprint`, `SharedSecret`;
  `Validate()` warnings mirroring `AlarmHistorianOptions` (empty SharedSecret, etc.).
- Modify: `src/Server/ZB.MOM.WW.OtOpcUa.Runtime/ServiceCollectionExtensions.cs`
  - `AddOtOpcUaRuntime`: `services.TryAddSingleton<IHistorianDataSource>(NullHistorianDataSource.Instance);`
  - Add `AddServerHistorian(this IServiceCollection, IConfiguration, Func<ServerHistorianOptions,
    IServiceProvider, IHistorianDataSource> factory)` — bind the section; `Enabled != true` ⇒ no-op
    (Null stays); else log `Validate()` warnings + `AddSingleton<IHistorianDataSource>(sp =>
    factory(opts, sp))`. Mirror `AddAlarmHistorian`.
- Modify: `src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OtOpcUaSdkServer.cs` — add
  `public bool SetHistorianDataSource(IHistorianDataSource? source)` mirroring `SetNodeWriteGateway`.
- Modify: `src/Server/ZB.MOM.WW.OtOpcUa.Host/Program.cs` — after `AddAlarmHistorian` (`:94`), add
  `AddServerHistorian(config, (opts,sp) => new WonderwareHistorianClient(new
  WonderwareHistorianClientOptions(opts.Host, opts.Port, opts.SharedSecret){ UseTls=opts.UseTls,
  ServerCertThumbprint=opts.ServerCertThumbprint }, sp.GetService<ILogger<WonderwareHistorianClient>>()))`.
- Modify: `src/Server/ZB.MOM.WW.OtOpcUa.Host/OpcUa/OtOpcUaServerHostedService.cs` — after
  `SetNodeWriteGateway` (`:147`), resolve `IHistorianDataSource` from DI and
  `_server.SetHistorianDataSource(source)`; in `StopAsync` (`:166`) `_server?.SetHistorianDataSource(null)`.
  (The hosted service must be able to resolve `IHistorianDataSource` — inject it or pull from the
  provider exactly as the other sinks are obtained.)
- Modify: `src/Server/ZB.MOM.WW.OtOpcUa.Host/appsettings.json` — add a disabled `ServerHistorian`
  block (documented defaults). **Do not** put a real `SharedSecret` in a tracked file (leave `""`).
- Test: `tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Historian/AddServerHistorianTests.cs` (new;
  model on the existing `AddAlarmHistorian` DI test) — disabled ⇒ resolves `NullHistorianDataSource`;
  enabled ⇒ resolves the factory's source.

**Steps:**
1. Failing DI test: `ServerHistorian:Enabled=false` ⇒ `IHistorianDataSource` is the Null instance;
   `Enabled=true` ⇒ the factory's fake. Run → fail.
2. Implement `ServerHistorianOptions` + `AddServerHistorian` + the `TryAddSingleton` default + the
   `SetHistorianDataSource` setter. Run → pass.
3. Wire the Host (`Program.cs` + hosted service + appsettings). Build the **Host** project to prove
   the Wonderware factory + DI compile (no unit test for the Host wiring — it's covered by the live
   gate). Build clean.
4. Commit by path (do NOT stage appsettings.json secrets — the block is disabled with empty secret).

---

### Task 6: Docs + bookkeeping

**Classification:** small · **Estimated implement time:** ~4 min · **Parallelizable with:** none

**Files:**
- Create: `docs/Historian.md` — the historized-tag `TagConfig` schema (`isHistorized`,
  `historianTagname` default=FullName), the `ServerHistorian` config section, HistoryRead behavior
  (the four variants, graceful degrade to `GoodNoData`, the single-shot/no-continuation limitation,
  events-on-equipment-folders), and a `Client.CLI historyread` example.
- Modify: `CLAUDE.md` — a short pointer under a Historian/HistoryRead note (one paragraph + the doc link).
- Modify (disk-only, **do NOT commit**): `pending.md` — mark #2 Phase C done with the merge SHA +
  the deferred live gate.
- Update: the plan's `.tasks.json` statuses.

**Steps:** Write the docs; commit `docs/Historian.md` + `CLAUDE.md` by path. Update `pending.md` on
disk only (never staged).

---

### Task 7: Live docker-dev `/run` verification — DEFERRED (user-driven)

**Classification:** n/a (live) · **Parallelizable with:** none · **Depends on:** Task 5

**Deferred — the agent does NOT sign in and the local docker-dev rig has no Wonderware sidecar.** The
historian backend is the WW Historian VM (`10.100.0.48`) + AVEVA, so this gate is operator-driven.
When run: author a historized Galaxy equipment tag (`TagConfig` `"isHistorized":true`), set
`ServerHistorian:Enabled=true` pointed at the sidecar (`Host`/`Port`/`SharedSecret`/TLS), deploy on
`MAIN-galaxy-eq` (`POST http://localhost:9200/api/deployments`, `X-Api-Key: docker-dev-deploy-key`),
then `Client.CLI historyread -u opc.tcp://localhost:4840 -n "ns=2;s=<equip>/<tag>" --start … --end …`
→ samples return; a non-historized tag ⇒ `BadHistoryOperationUnsupported`.

---

## Dependency graph

`0 → 1 → 2 → 3 → (4 ∥ 5) → 6 → 7(deferred)`. Tasks 4 and 5 touch disjoint files
(node-manager events arm vs. DI/Host/SdkServer) and may be dispatched concurrently after Task 3.

## Done

Build clean (0 warnings in `src/`) + `dotnet test` green (new + existing suites) for Tasks 1–6. The
live `/run` (Task 7) is the deferred user-driven gate.