# Step 13: Element Definition and Domain Ownership

## 담당 역할과 필수 스킬

- 담당 역할: `implementation-agent`
- 필수 스킬: `harness`, `fesa-cpp-msvc-tdd`
- 이 Step만 `RED -> observed failure -> minimal GREEN -> focused/full VERIFY`로 수행한다.

## 읽어야 할 파일

- `/AGENTS.md`
- `/docs/CODINGSTYLE.md`
- `/docs/ARCHITECTURE.md`
- `/docs/ADR.md`
- `/docs/cpp-object-oriented-modular-refactoring/implementation-plan.md`
- Step 11 `source_target_resolver` files
- Step 12 material/property headers and tests
- `/include/fesa/model/model_types.h`
- `/include/fesa/model/domain.h`, `/src/fesa/model/domain.cpp`
- `/include/fesa/analysis/analysis_model.h`, `/src/fesa/analysis/analysis_model.cpp`
- `/src/fesa/io/abaqus/domain_mapper.cpp`
- matching Domain, AnalysisModel and DomainMapper tests
- `/src/fesa/CMakeLists.txt`, `/tests/CMakeLists.txt`
- `/phases/cpp-object-oriented-modular-refactoring/index.json`
- `/phases/cpp-object-oriented-modular-refactoring/step13.md`

## 작업

Requirements `R-MODEL-001` and `R-ELEMENT-001`의 semantic ownership을 구현한다.

1. Domain/AnalysisModel/mapper tests에 `C-MODEL-002`를 먼저 추가한다. Tests verify mixed
   B33/MITC4 definition ownership through base references, vector-position `EntityIndex`, insertion
   order, const access, move-only Domain, and Domain-outlives-AnalysisModel contract.
2. Missing base/ownership API로 RED compile failure를 기록한다.
3. Candidate interface:

```cpp
enum class ElementDefinitionKind { kEulerBeam3D, kMitc4Shell };

class ElementDefinition {
 public:
  virtual ~ElementDefinition() = default;
  virtual ElementDefinitionKind Kind() const noexcept = 0;
  virtual const SourceEntityId& SourceId() const noexcept = 0;
  virtual std::string_view SourceElementType() const noexcept = 0;
  virtual const std::vector<EntityIndex>& NodeIndices() const noexcept = 0;
  virtual EntityIndex PropertyIndex() const noexcept = 0;
};
```

4. Create `/include/fesa/elements/element_definition.h`. Keep concrete definitions in the
   current `/include/fesa/elements/euler_beam_3d.h` and
   `/include/fesa/elements/mitc4_shell.h` ownership modules rather than creating a second record
   location.
5. Existing `EulerBeam3DDefinition` and `Mitc4ShellDefinition` become final concrete definitions;
   preserve B33 vs S4/S4R source type and FESA internal identity.
6. Domain owns `std::vector<std::unique_ptr<ElementDefinition>>`,
   `std::vector<std::unique_ptr<ElementProperty>>`, and
   `std::vector<std::unique_ptr<Material>>`. Accessors return const base references or const
   collection views; Domain copy is disabled and move is allowed if existing construction needs it.
7. Mapper builds a complete validated candidate before moving it into Domain. Failed mapping must
   not leave a partially visible Domain.
8. AnalysisModel remains a non-owning active index/reference view and never copies Domain.

## Acceptance Criteria

```powershell
cmake --build .harness/build --config Debug --target fesa_unit_tests
ctest --test-dir .harness/build -C Debug `
  -R "ElementDefinition|DomainModel|AnalysisModel|InpDomainMapping" --output-on-failure
& "C:/Program Files/LLVM/bin/clang-format.exe" --dry-run --Werror `
  include/fesa/elements/element_definition.h `
  include/fesa/model/domain.h src/fesa/model/domain.cpp `
  tests/unit/model/domain_test.cpp tests/unit/analysis/analysis_model_test.cpp `
  tests/unit/io/abaqus/domain_mapper_test.cpp
cmake --build .harness/build --config Debug
ctest --test-dir .harness/build -C Debug --show-only=json-v1
ctest --test-dir .harness/build -C Debug --output-on-failure
```

## 검증 및 상태 갱신

- RED, stable ownership/order/lifetime focused tests, mapper and full CTest를 summary에 기록한다.
- Index/order/lifetime regression is `error`; missing ownership decision is `blocked`.
- 성공 시 현재 Step만 `completed`로 갱신한다.
- timestamp, retry, commit, advancement는 Executor 소유다.

## 금지사항

- `Clone()` or `shared_ptr`를 추가하지 마라. 이유: Domain has unique immutable ownership.
- Node/Element에 equation id를 저장하지 마라.
- Runtime Element methods를 semantic definition에 넣지 마라.
- 직접 commit하거나 hook script를 수동 실행하지 마라.
