# Implementation Plan: Job 903 — Admin Challenges Import must Replace, Modal must Auto-Close

## 1. Architectural Reconnaissance

- **Codebase style & conventions:**
  - Backend: NestJS (TypeScript, `strict`, class-based `Injectable` services, TypeORM with `better-sqlite3`, async/await, controllers delegating to services).
  - Frontend: Angular 20 standalone components with `ChangeDetectionStrategy.OnPush`, signal `input()` / `output()`, `@if`/`@for` control flow, RxJS only for the search debounce, smart/dumb split. Pure helpers live in `*.pure.ts` and are tested directly without a TestBed.
  - Tests: Jest + ts-jest configured in `tests/jest.config.js` as two projects (`backend`, `frontend`). Backend specs use `Test.createTestingModule` with in-memory SQLite and a unique `mkdtempSync` upload dir per file (no shared FS races). Frontend specs in `tests/frontend/` import pure helpers directly (no DOM) — the only TestBed specs are for components that must exercise `@Input` bindings.
  - `npm test` at the repo root runs **all** tests for **all** components via the Jest project selector.

- **Data Layer:**
  - SQLite via TypeORM; relevant tables `challenge`, `challenge_file`, `category`, `solve`.
  - File storage: `data/uploads/challenges/<uuid>` for committed files, `.staging/<uuid>` for in-flight uploads.
  - Repository injection via `@InjectRepository(Entity)`; transactions via `this.dataSource.transaction(async (manager) => { ... })`.

- **Test Framework & Structure:**
  - Backend tests in `/repo/tests/backend/*.spec.ts` (Jest, `testEnvironment: 'node'`).
  - Frontend tests in `/repo/tests/frontend/*.spec.ts` (Jest + `jsdom`); pure-helper specs do not need TestBed.
  - Single command: `npm test` (already wired in root `package.json`).
  - New specs to add: one backend spec for the replace-all-on-confirmed-import behavior, one frontend spec for the auto-close + list-refresh behavior of the import modal. Both must be runnable with `npm test`.

- **Required Tools & Dependencies:** No new tools or packages. Existing `better-sqlite3`, TypeORM, NestJS, Angular, and Jest setup is sufficient.

## 2. Impacted Files

- **To Modify:**
  - `backend/src/modules/admin/challenges.service.ts` — change `importConfirmed()` so it wipes every pre-existing `challenge` (and cascade-deletes their `challenge_file` + `solve` rows) before re-inserting from the document. Re-link the now-unreferenced disk files for unlink and unlink any orphaned file rows after the swap.
  - `frontend/src/app/features/admin/challenges/challenges.component.ts` — after a successful confirmed import (`onImportConfirm`), call `closeImport()` so the dialog disappears (it currently stays open showing the result message and a manual Close button).
  - `docs/guides/admin-challenges.md` — clarify that **Import with `?confirm=overwrite` replaces the entire challenge set** (not just upserts by name). Update the "Importing the same document twice is idempotent" line to state the full-replace semantics.
  - `docs/architecture/key-files.md` — update the one-line responsibility for `challenges.service.ts` to mention the replace-on-confirmed-import contract.

- **To Create:**
  - `tests/backend/admin-challenges-import-replace.spec.ts` — focused contract test asserting that an overwrite-confirmed import removes pre-existing challenges (including their files and solves) and leaves only the imported set; checks both DB and the on-disk `challenges/` directory.
  - `tests/frontend/admin-challenges-import-autoclose.spec.ts` — pure/smart test asserting that after a successful `onImportConfirm`, the import modal closes (i.e. `importOpen()` flips to `false`) and the result is still surfaced via the page-level status banner.

## 3. Proposed Changes

### 3.1 Backend — `AdminChallengesService.importConfirmed` becomes a full replace

In `backend/src/modules/admin/challenges.service.ts`, refactor `importConfirmed` (currently lines 412–522) so the confirmed path:

1. **Stage every file up front** (unchanged logic, lines 421–446). Keep the early `rollbackStaged` on validation failure.
2. **Inside one transaction** (unchanged transaction wrapper, line 450):
   a. Load every existing challenge row with `manager.getRepository(ChallengeEntity).find()` (no filter).
   b. Capture each existing challenge's `ChallengeFileEntity` rows (`find({ where: { challengeId: In(ids) } })`) so we know which `storedFilename`s are still referenced after the transaction.
   c. Delete every existing challenge row with a single `manager.delete(ChallengeEntity, {})` — TypeORM cascades to `challenge_file` and `solve` rows via the existing FK cascade. This is the **replace** semantics.
   d. Then iterate `doc.challenges` and (as today) skip entries whose category is unknown, otherwise create a new challenge row + new file rows pointing at the already-staged tokens. Result counts stay `{ imported, skipped, warnings }`.
3. **After commit, clean up disk** — for the captured pre-existing stored filenames, call `fileService.removeFinal(storedFilename)` best-effort (same helper used by `remove()`). Newly-inserted challenges' files are then committed via the existing `commit(item.staged.token)` loop (lines 506–517).
4. **Do not break the preview path.** `previewImport` keeps the existing conflict/unknown-category logic; the destructive replace only happens when `?confirm=overwrite` (controller path `admin-challenges.controller.ts:87-92`).
5. **No changes to DTOs or to the export shape.** `exportAll()` already produces the versioned envelope that the new behavior requires for round-tripping.

**Edge cases to handle explicitly:**
- Empty `doc.challenges` ⇒ result `{ imported: 0, skipped: [], warnings: [] }`; existing rows are wiped, files unlinked, no new rows created.
- Unknown-category rows ⇒ counted in `skipped`; do **not** preserve them, do **not** abort the wipe. The wipe happens before the per-challenge inserts.
- Disk-unlink failure for a removed file ⇒ swallow + log via `ChallengeFilesService.removeFinal` (matches existing delete behavior, never throws).

### 3.2 Frontend — `AdminChallengesComponent.onImportConfirm` closes the modal

In `frontend/src/app/features/admin/challenges/challenges.component.ts`:

- In `onImportConfirm()` (lines 455–470), after `await this.load()` succeeds and `importResult` is set, additionally call `closeImport()`. `closeImport()` already clears `importDoc`, `importPreview`, `importResult`, and `importError` (lines 447–453) and resets `importOpen` to `false`.
- The page-level status banner is already populated by `this.statusMessage.set(summarizeImportResult(result))` immediately before `closeImport()`, so the user still sees the "Imported N challenges" message after the dialog closes.
- The `<app-challenge-import-modal>` template already renders a "Close" button while `result()` is set; that branch becomes unreachable after the fix (the modal will close before the user can click it), so no template change is required. The result branch is kept as a defensive fallback for any future flow that intentionally keeps the modal open (e.g. partial-failure display).

### 3.3 Docs — clarify the replace semantics

- `docs/guides/admin-challenges.md` — under the "Import" section (line 103) replace the third bullet ("Click Overwrite & Import … the server upserts challenges inside one transaction by case-insensitive name") with: "Click **Overwrite & Import** → the client posts the same document with `?confirm=overwrite`. The server stages every file up front (rolling back any FS failure), then **wipes every existing challenge (cascade-deleting their `challenge_file` and `solve` rows and best-effort unlinking their disk files) and inserts the archive's challenges** in one transaction."
- Update the last "Notes" line on idempotency (line 138) to: "Importing the same document twice is idempotent: every existing challenge (matching or not) is replaced by the archive contents."
- `docs/architecture/key-files.md` — update the `challenges.service.ts` responsibility to "... CRUD, list aggregates, transactional deletion, export, full-replace import orchestration."

## 4. Test Strategy

### 4.1 Backend contract test — `tests/backend/admin-challenges-import-replace.spec.ts`

- Mirror the wiring of `tests/backend/admin-challenges-import-export.spec.ts`: `:memory:` SQLite, unique `mkdtempSync(os.tmpdir() + '/hipctf-challenges-import-replace-…')` `UPLOAD_DIR`, all migrations including `UpgradeChallengeAdminSchema1700000000500`, TypeOrmModule.forFeature for `CategoryEntity`, `ChallengeEntity`, `ChallengeFileEntity`, `SolveEntity`.
- AAA structure. Mocking strategy: no external boundaries — use real in-memory SQLite + real `ChallengeFilesService` writing to the temp dir. Isolation: per-file temp dir (no parallel FS races).
- Tests (minimal, one logical assertion each):
  1. **Replace wipes unrelated challenges** — Seed `Alpha` (CRY, NC, port=1337, flag='flag{a}', with one staged file committed) and `Bravo` (CRY, WEB). Call `importConfirmed` with a single-challenge doc `{ name: 'Imported Charlie', … categorySystemKey: 'CRY', … }`. Assert `list({}).map(r => r.name)` is exactly `['Imported Charlie']` and that `chRepo.count()` equals 1.
  2. **Disk files of wiped challenges are unlinked** — Capture the stored filename of Alpha's committed file via `fileRepo.findOne({ where: { challengeId: alpha.id } })`. After the import, assert `fs.existsSync(path.join(finalDir, alphaStoredName))` is `false`, while the new challenge's stored file exists.
  3. **Empty archive wipes everything** — Re-seed Alpha, then `importConfirmed` with `{ challenges: [] }`. Assert `chRepo.count() === 0` and the previously-committed disk file is unlinked.
  4. **Unknown-category rows are skipped, not preserved** — Seed `Keep` (WEB). Import a doc containing one unknown-category challenge plus nothing else. Assert `result.skipped` has length 1 and `list({})` is empty (the wipe still happened).

### 4.2 Frontend modal test — `tests/frontend/admin-challenges-import-autoclose.spec.ts`

- Smart container test using `TestBed.createComponent(AdminChallengesComponent)` to exercise the live handler.
- Mock `AdminService` (`jest.fn()` for `previewChallengeImport`, `confirmChallengeImport`, `listChallenges`, `listCategories`, `exportChallenges`) and stub the document `createElement('input')` file-picker flow by setting `importDoc`/`importPreview` directly via a small helper (or by calling the public `openImport()` + injecting the file via a fake `<input>` ref). Keep it minimal: directly drive the component signals is preferable to mocking the file picker.
- AAA structure. Mocking strategy: only `AdminService` (network boundary). No DOM snapshotting; we assert on signal values (OnPush friendly) and DOM text via `fixture.nativeElement.textContent` if needed.
- Tests:
  1. **`onImportConfirm` closes the modal after success** — arrange: `component.importOpen.set(true)`, `component.importDoc.set({ … })`, `component.importPreview.set({ total: 1, conflicts: [], unknownCategories: [], warnings: [] })`. Stub `admin.confirmChallengeImport` to resolve `{ imported: 1, skipped: [], warnings: [] }` and `admin.listChallenges` to resolve `[]`. Act: `await component.onImportConfirm()`. Assert `component.importOpen()` is `false`, `component.importResult()` is `null` (cleared by `closeImport`), and `component.statusMessage()` contains "Imported 1".
  2. **`onImportConfirm` keeps the modal open when the network call rejects** — arrange same, stub `confirmChallengeImport` to reject with a generic error. Act + assert `component.importOpen()` stays `true` and `component.importError()` is non-null.

### 4.3 Run command

- From the repo root: `npm test` (or `npm run test:backend` / `npm run test:frontend` for individual projects). Both new specs run inside the existing `ts-jest` configuration with no additional setup.