# Story 1.6: Legacy Anti-Corruption Data Access Layer

Status: ready-for-dev

## Story

As a a developer,
I want a dedicated read-only data access layer for legacy Access-derived entities using fixed join keys,
so that legacy data is available to all features without any risk of schema mutation or direct table coupling.

## Acceptance Criteria

1. **Given** a feature requests municipality or jurisdiction data **When** the anti-corruption layer is called **Then** it returns data joined by ID, JCode/JurisCode, or KitID without modifying any legacy table structure or content (NFR12)
2. **Given** the anti-corruption layer executes any query **When** the operation is inspected **Then** only SELECT operations are permitted — INSERT, UPDATE, and DELETE on legacy entities are blocked at the layer boundary
3. **Given** legacy data is returned through the layer **When** mapped to the application domain **Then** it is converted to strongly-typed domain model objects before being returned to any calling feature
4. **Given** any application code outside the layer attempts to query legacy tables directly **When** reviewed in code **Then** no such direct access exists — the anti-corruption layer is the sole access point for legacy data

## Tasks / Subtasks

- [ ] Implement story behavior in aligned backend/frontend modules (AC: #1)
  - [ ] Add or update API/service/UI components required by the story scope
  - [ ] Keep legacy Access entities read-only and route writes to extension-layer structures
- [ ] Cover acceptance criteria #2 in implementation and tests (AC: #2)
  - [ ] Add validation/error handling and UX state updates as needed
- [ ] Cover acceptance criteria #3 in implementation and tests (AC: #3)
  - [ ] Add validation/error handling and UX state updates as needed
- [ ] Cover acceptance criteria #4 in implementation and tests (AC: #4)
  - [ ] Add validation/error handling and UX state updates as needed
- [ ] Validate and document completion evidence
  - [ ] Verify build/tests for touched modules
  - [ ] Capture changed files and any migration/config implications

## Dev Notes

- Follow Epic 1 architecture constraints: ASP.NET Core + React separation, RBAC-aware patterns, and immutable legacy tables.
- Reuse shared component and workflow patterns defined in UX and architecture docs; avoid parallel custom implementations.
- Keep changes scoped to this story; do not pull forward Epic 2+ features.

### Project Structure Notes

- Backend: `BriansClientRouteReports.Server/`
- Frontend: `brians-client-route-reports-client/`
- Story artifacts: `_bmad-output/implementation-artifacts/`

### References

- Story source: `_bmad-output/planning-artifacts/epics.md` (Epic 1 / Story 1.6)
- Architecture constraints: `_bmad-output/planning-artifacts/architecture.md`
- UX patterns: `_bmad-output/planning-artifacts/ux-design-specification.md`

## Dev Agent Record

### Agent Model Used

GPT-5 Codex

### Debug Log References

- Story generated from epic source and architecture/UX planning artifacts.

### Completion Notes List

- Story context created and marked ready-for-dev.

### File List

- `_bmad-output/implementation-artifacts/1-6-legacy-anti-corruption-data-access-layer.md`