# Step 3: analysis-base-interface

## Read First

Read these files before editing:

- `/AGENTS.md`
- `/docs/PLAN.md`
- `/docs/PROGRESS.md`
- `/docs/WORKNOTE.md`
- `/docs/AGENT_RULES.md`
- `/docs/ADR.md`
- `/docs/ARCHITECTURE.md`
- `/docs/implementation-plans/analysis-state-analysis-base-implementation-plan.md`
- `/include/fesa/core/Domain.hpp`
- `/include/fesa/core/AnalysisState.hpp`
- `/CMakeLists.txt`

## Task

Add `fesa::analysis::Analysis` as a minimal base interface for future analysis strategies.

Candidate files:

- Create `/include/fesa/analysis/Analysis.hpp`
- Create `/tests/analysis/analysis_base_test.cpp`
- Modify `/CMakeLists.txt`

Required contract:

- `Analysis` has a virtual destructor.
- `Analysis` exposes `const char* name() const noexcept`.
- `Analysis` exposes `void run(const fesa::core::Domain& domain, fesa::core::AnalysisState& state)`.
- `run` delegates to a protected pure virtual `doRun(const fesa::core::Domain&, fesa::core::AnalysisState&)`.
- `Domain` is passed as const; `AnalysisState` is mutable.
- The base class must not own `Domain`, `AnalysisState`, solver objects, result writers, or reference artifacts.

## Tests To Write First

Write tests in `/tests/analysis/analysis_base_test.cpp` before production changes:

- a derived recording analysis can be used through `Analysis&`.
- `run` forwards the const `Domain` and mutable `AnalysisState` to the derived implementation.
- derived implementation can update `AnalysisState` without mutating `Domain`.
- `Analysis` can be deleted through a base pointer.

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 3 with `completed`, `error`, or `blocked`.

## Do Not

- Do not implement `LinearStaticAnalysis`.
- Do not add template-method hook lists for assembly, solve, boundary conditions, or output until `AnalysisModel` and `DofManager` exist.