# WCS P0-B1 Offline SHADOW Demo Implementation Plan

> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [x]`) syntax for tracking.

**Goal:** Extend `javaTest` with a deterministic, fail-closed, in-memory P0-B1 SHADOW traffic-control kernel without changing the existing LEGACY demo or production modules.

**Architecture:** New code lives under `com.ft546.wcs.shadow` and reads immutable snapshots to produce `GRANT/HOLD/YIELD` decisions and replayable events. The SHADOW application layer receives read-only resource state and write-forbidden ports, while state-machine and feedback tests exercise simulated HARD/UNKNOWN_HARD contracts independently of authoritative LEGACY state.

**Tech Stack:** Java 8, Maven, JUnit Jupiter 5.10.2, Jackson Databind 2.17.2, Surefire 3.2.5.

## Global Constraints

- Keep Java source and target compatibility at Java 8.
- Keep all existing LEGACY behavior and tests passing.
- Do not modify any `ruoyi-*` production code.
- Do not connect SQL Server, PLC, WMS, Spring, or network services.
- SHADOW must not write PLC commands, LEGACY business state, or authoritative reservations.
- Traffic zones are coordination/version boundaries, not implicit capacity-one resources.
- `HARD` and `UNKNOWN_HARD` are released only by matching feedback, never by ETA expiry.
- Unknown cargo, lift signals, restart, disconnect, and feedback mismatch fail closed.
- The result is offline SHADOW simulation evidence, not field SHADOW, HIL, ACTIVE, or production evidence.

---

### Task 1: Versioned Map and Resource Ledger

**Files:**
- Modify: `javaTest/pom.xml`
- Create: `javaTest/src/main/java/com/ft546/wcs/shadow/map/EffectiveTrafficMap.java`
- Create: `javaTest/src/main/java/com/ft546/wcs/shadow/map/TrafficMapCompiler.java`
- Create: `javaTest/src/main/java/com/ft546/wcs/shadow/resource/ResourceKey.java`
- Create: `javaTest/src/main/java/com/ft546/wcs/shadow/resource/ResourceLedger.java`
- Test: `javaTest/src/test/java/com/ft546/wcs/shadow/MapAndResourceLedgerTest.java`

**Interfaces:**
- Produces: `TrafficMapCompiler.compile(MapDefinition): EffectiveTrafficMap`
- Produces: `ResourceKey.node(String)`, `edge(String,String)`, `conflict(String)`
- Produces: `ResourceLedger.evaluate(String, Collection<ResourceKey>): ProtectionResult`

- [x] **Step 1: Write failing map and ledger tests**

Cover checksum mismatch, unconfirmed zone, canonical undirected edge key, zone non-exclusivity, same-node conflict, opposite-edge conflict, capacity, and non-conflicting parallel candidates.

```java
assertEquals("EDGE:A:B", ResourceKey.edge("B", "A").value());
assertTrue(ledger.evaluate("V1", Arrays.asList(ResourceKey.node("N1"))).isGranted());
assertFalse(ledger.evaluate("V2", Arrays.asList(ResourceKey.node("N1"))).isGranted());
```

- [x] **Step 2: Run the focused test and verify RED**

Run: `mvn -f javaTest/pom.xml -Dtest=MapAndResourceLedgerTest test`

Expected: compilation failure because the SHADOW types do not exist.

- [x] **Step 3: Implement immutable map compilation and ledger evaluation**

`EffectiveTrafficMap` exposes immutable nodes, edges, capacities, safe wait/yield sites, `mapCode`, `versionId`, and checksum. `ResourceLedger` copies authoritative protection input and mutates only its private simulation state.

- [x] **Step 4: Run focused and existing tests**

Run: `mvn -f javaTest/pom.xml -Dtest=MapAndResourceLedgerTest test`

Run: `mvn -f javaTest/pom.xml test`

- [x] **Step 5: Commit**

```bash
git add javaTest/pom.xml javaTest/src/main/java/com/ft546/wcs/shadow/map javaTest/src/main/java/com/ft546/wcs/shadow/resource javaTest/src/test/java/com/ft546/wcs/shadow/MapAndResourceLedgerTest.java
git commit -m "feat: model shadow traffic resources"
```

### Task 2: Segment State and Immutable Snapshot

**Files:**
- Create: `javaTest/src/main/java/com/ft546/wcs/shadow/segment/ReservationState.java`
- Create: `javaTest/src/main/java/com/ft546/wcs/shadow/segment/SegmentState.java`
- Create: `javaTest/src/main/java/com/ft546/wcs/shadow/segment/TrafficSegment.java`
- Create: `javaTest/src/main/java/com/ft546/wcs/shadow/snapshot/TrafficVehicleSnapshot.java`
- Create: `javaTest/src/main/java/com/ft546/wcs/shadow/snapshot/TrafficSnapshot.java`
- Create: `javaTest/src/main/java/com/ft546/wcs/shadow/snapshot/SnapshotFreshnessPolicy.java`
- Test: `javaTest/src/test/java/com/ft546/wcs/shadow/SegmentAndSnapshotTest.java`

**Interfaces:**
- Produces: `TrafficSegment.transition(SegmentEvent): TrafficSegment`
- Produces: `SnapshotFreshnessPolicy.validate(previous,current,decisionTime): SnapshotHealth`

- [x] **Step 1: Write failing state and snapshot tests**

Assert PREPARED cannot jump to EXECUTING, COMMIT uncertainty creates UNKNOWN_HARD, snapshot collections are frozen, stale snapshots are rejected, sequence rollback is rejected, and boot ID change quarantines the vehicle.

- [x] **Step 2: Run focused test and verify RED**

Run: `mvn -f javaTest/pom.xml -Dtest=SegmentAndSnapshotTest test`

- [x] **Step 3: Implement state transitions and snapshot validation**

Only allow:

```text
SOFT_PLANNED -> PREPARING -> PREPARED -> COMMITTING -> COMMITTED -> EXECUTING -> COMPLETED
COMMITTING -> COMMIT_UNCERTAIN
COMMITTED/EXECUTING -> FAULT_LOCKED
```

All snapshot lists and maps are defensive unmodifiable copies.

- [x] **Step 4: Run focused and full tests**

Run: `mvn -f javaTest/pom.xml -Dtest=SegmentAndSnapshotTest test`

Run: `mvn -f javaTest/pom.xml test`

- [x] **Step 5: Commit**

```bash
git add javaTest/src/main/java/com/ft546/wcs/shadow/segment javaTest/src/main/java/com/ft546/wcs/shadow/snapshot javaTest/src/test/java/com/ft546/wcs/shadow/SegmentAndSnapshotTest.java
git commit -m "feat: validate shadow segment snapshots"
```

### Task 3: Wait Graph and Rolling Decisions

**Files:**
- Create: `javaTest/src/main/java/com/ft546/wcs/shadow/decision/DecisionType.java`
- Create: `javaTest/src/main/java/com/ft546/wcs/shadow/decision/ShadowCandidate.java`
- Create: `javaTest/src/main/java/com/ft546/wcs/shadow/decision/ShadowDecision.java`
- Create: `javaTest/src/main/java/com/ft546/wcs/shadow/decision/WaitForGraph.java`
- Create: `javaTest/src/main/java/com/ft546/wcs/shadow/decision/RollingDispatchPolicy.java`
- Test: `javaTest/src/test/java/com/ft546/wcs/shadow/RollingDispatchPolicyTest.java`

**Interfaces:**
- Produces: `WaitForGraph.wouldCreateCycle(waiter,holders): boolean`
- Produces: `RollingDispatchPolicy.decide(List<ShadowCandidate>, ResourceLedger, EffectiveTrafficMap): List<ShadowDecision>`

- [x] **Step 1: Write failing deterministic decision tests**

Cover stable priority/aging/task/vehicle ordering, same-node and opposite-edge HOLD, non-conflicting parallel GRANT, committed segment non-revocation, cycle rejection, safe YIELD, and no-safe-yield HOLD.

```java
assertEquals(Arrays.asList("V1", "V2"), decisions.stream()
    .map(ShadowDecision::getVehicleId).collect(Collectors.toList()));
assertEquals(DecisionType.HOLD, cycleDecision.getType());
assertEquals("WAIT_CYCLE", cycleDecision.getReasonCode());
```

- [x] **Step 2: Run focused test and verify RED**

Run: `mvn -f javaTest/pom.xml -Dtest=RollingDispatchPolicyTest test`

- [x] **Step 3: Implement deterministic rolling policy**

Sort by committed continuation, emergency, business priority descending, wait age descending, clearance cost ascending, task ID, and vehicle ID. Every non-GRANT decision includes reason code, conflicting resources, and blocking vehicles.

- [x] **Step 4: Run focused and full tests**

Run: `mvn -f javaTest/pom.xml -Dtest=RollingDispatchPolicyTest test`

Run: `mvn -f javaTest/pom.xml test`

- [x] **Step 5: Commit**

```bash
git add javaTest/src/main/java/com/ft546/wcs/shadow/decision javaTest/src/test/java/com/ft546/wcs/shadow/RollingDispatchPolicyTest.java
git commit -m "feat: decide shadow traffic safely"
```

### Task 4: Feedback Reconciliation and Fail-Closed Recovery

**Files:**
- Create: `javaTest/src/main/java/com/ft546/wcs/shadow/feedback/ExecutionFeedback.java`
- Create: `javaTest/src/main/java/com/ft546/wcs/shadow/feedback/FeedbackResult.java`
- Create: `javaTest/src/main/java/com/ft546/wcs/shadow/feedback/FeedbackReconciler.java`
- Test: `javaTest/src/test/java/com/ft546/wcs/shadow/FeedbackReconcilerTest.java`

**Interfaces:**
- Produces: `FeedbackReconciler.reconcile(TrafficSegment, ExecutionFeedback): FeedbackResult`

- [x] **Step 1: Write failing feedback tests**

Cover A-to-B release, destination retention, duplicate snapshot idempotency, ETA expiry retention, version mismatch, skip, rollback, disconnect, ACK loss, and PLC restart.

- [x] **Step 2: Run focused test and verify RED**

Run: `mvn -f javaTest/pom.xml -Dtest=FeedbackReconcilerTest test`

- [x] **Step 3: Implement matching and release rules**

Only matching boot ID, epoch, plan version, segment sequence, increasing snapshot sequence, and legal path suffix can release resources. Every mismatch returns quarantined `UNKNOWN_HARD` with zero released resources.

- [x] **Step 4: Run focused and full tests**

Run: `mvn -f javaTest/pom.xml -Dtest=FeedbackReconcilerTest test`

Run: `mvn -f javaTest/pom.xml test`

- [x] **Step 5: Commit**

```bash
git add javaTest/src/main/java/com/ft546/wcs/shadow/feedback javaTest/src/test/java/com/ft546/wcs/shadow/FeedbackReconcilerTest.java
git commit -m "feat: reconcile feedback fail closed"
```

### Task 5: SHADOW Guard, Events, JSON Replay, and Demo

**Files:**
- Create: `javaTest/src/main/java/com/ft546/wcs/shadow/application/ShadowWriteForbiddenException.java`
- Create: `javaTest/src/main/java/com/ft546/wcs/shadow/application/ShadowWritePort.java`
- Create: `javaTest/src/main/java/com/ft546/wcs/shadow/application/ShadowTrafficCoordinator.java`
- Create: `javaTest/src/main/java/com/ft546/wcs/shadow/replay/DecisionEvent.java`
- Create: `javaTest/src/main/java/com/ft546/wcs/shadow/replay/DecisionReplayService.java`
- Create: `javaTest/src/test/resources/shadow/golden/basic-conflict.json`
- Create: `javaTest/src/test/java/com/ft546/wcs/shadow/ShadowCoordinatorReplayTest.java`
- Modify: `javaTest/src/main/java/com/ft546/wcs/demo/DemoApplication.java`
- Modify: `javaTest/src/test/java/com/ft546/wcs/demo/DemoScenarioTest.java`

**Interfaces:**
- Produces: `ShadowTrafficCoordinator.run(TrafficSnapshot,List<ShadowCandidate>): DecisionEvent`
- Produces: `DecisionReplayService.read(InputStream): DecisionEvent`
- Produces: `DecisionReplayService.replay(DecisionEvent): List<ShadowDecision>`

- [x] **Step 1: Write failing guard and replay tests**

Assert PLC/business/reservation writes all throw, coordinator leaves LEGACY state unchanged, JSON replay reproduces type/reason/resources, and Demo output contains an explicit offline SHADOW summary.

- [x] **Step 2: Run focused tests and verify RED**

Run: `mvn -f javaTest/pom.xml -Dtest=ShadowCoordinatorReplayTest,DemoScenarioTest test`

- [x] **Step 3: Implement coordinator, guard, event hash, and replay**

Use Jackson only at the replay boundary. Hash canonical event input with SHA-256. The coordinator records intended decisions but never invokes a mutable external port.

- [x] **Step 4: Run focused tests and executable demo**

Run: `mvn -f javaTest/pom.xml -Dtest=ShadowCoordinatorReplayTest,DemoScenarioTest test`

Run: `mvn -f javaTest/pom.xml exec:java`

- [x] **Step 5: Commit**

```bash
git add javaTest/pom.xml javaTest/src/main/java/com/ft546/wcs/shadow/application javaTest/src/main/java/com/ft546/wcs/shadow/replay javaTest/src/test/resources/shadow javaTest/src/main/java/com/ft546/wcs/demo/DemoApplication.java javaTest/src/test
git commit -m "feat: replay guarded shadow decisions"
```

### Task 6: Fixed-Seed Invariants and Documentation

**Files:**
- Create: `javaTest/src/test/java/com/ft546/wcs/shadow/ShadowInvariantPropertyTest.java`
- Modify: `javaTest/README.md`

**Interfaces:**
- Consumes: `RollingDispatchPolicy`, `ResourceLedger`, `FeedbackReconciler`
- Produces: repeatable invariant regression output including seed, map version, and input summary.

- [x] **Step 1: Write fixed-seed invariant tests**

For seeds `546001` through `546010`, generate bounded 2-to-8 vehicle candidate sets and assert capacity never exceeds limits, committed wait graph remains acyclic, the same input gives the same decisions, and fault/unknown feedback never frees resources.

- [x] **Step 2: Run property test**

Run: `mvn -f javaTest/pom.xml -Dtest=ShadowInvariantPropertyTest test`

- [x] **Step 3: Update README**

Document package boundaries, `mvn clean test`, `mvn exec:java`, covered P0-B1 scenarios, and the explicit exclusions for SQL, PLC, HIL, real SHADOW, ACTIVE, and production.

- [x] **Step 4: Run final verification**

Run:

```bash
mvn -f javaTest/pom.xml clean test
mvn -f javaTest/pom.xml exec:java
```

Inspect Surefire XML and require `tests > 0`, `failures = 0`, `errors = 0`, and `skipped = 0`. Run `git diff --check` and confirm no changed path under `ruoyi-*`.

- [x] **Step 5: Commit**

```bash
git add javaTest/src/test/java/com/ft546/wcs/shadow/ShadowInvariantPropertyTest.java javaTest/README.md
git commit -m "test: verify shadow traffic invariants"
```