# Step 2: analysis-state-guards

## Read First

Read these files before editing:

- `/AGENTS.md`
- `/docs/PLAN.md`
- `/docs/PROGRESS.md`
- `/docs/WORKNOTE.md`
- `/docs/AGENT_RULES.md`
- `/docs/implementation-plans/analysis-state-analysis-base-implementation-plan.md`
- `/include/fesa/core/AnalysisState.hpp`
- `/src/core/AnalysisState.cpp`
- `/tests/core/analysis_state_test.cpp`
- `/CMakeLists.txt`

## Task

Extend `AnalysisState` with mutation and guard behavior.

Required contract:

- `resize(std::size_t dof_count)` resets every vector to the new size and fills with zero.
- `setDisplacement(std::vector<double>)`, `setExternalForce(std::vector<double>)`, `setInternalForce(std::vector<double>)`, `setResidual(std::vector<double>)`, and `setReaction(std::vector<double>)` replace one vector.
- setter inputs must match `dofCount()`.
- size mismatch throws `std::invalid_argument`.
- a failed setter must not mutate the existing vector.
- `clearForces()` zeros external force, internal force, residual, and reaction while leaving displacement unchanged.
- `currentTime()`, `incrementIndex()`, and `iterationIndex()` accessors exist with setters.

## Tests To Write First

Add tests in `/tests/core/analysis_state_test.cpp` before production changes:

- setters replace vectors when sizes match.
- mismatched setter input throws and preserves old values.
- resize resets all vectors to zero.
- clearForces preserves displacement and zeros force-like vectors.
- time, increment, and iteration counters can be updated.

Run the targeted test and confirm it fails before implementation:

```powershell
ctest --test-dir build/msvc-debug --output-on-failure -C Debug -R analysis
```

Then implement the minimum code needed to pass.

## Acceptance Criteria

Run:

```powershell
ctest --test-dir build/msvc-debug --output-on-failure -C Debug -R analysis
python scripts/validate_workspace.py
```

Update `/phases/analysis-state-analysis-base/index.json` step 2 with `completed`, `error`, or `blocked`.

## Do Not

- Do not add dynamics-only velocity or acceleration vectors in this phase.
- Do not add thermal temperature fields in this phase.
- Do not add equation numbering or DOF mapping responsibilities.