# Tasks: Cancel Event

**Input**: Design documents from `/specs/016-cancel-event/`
**Prerequisites**: plan.md, spec.md, research.md, data-model.md, contracts/patch-event-endpoint.yaml

**Tests**: Included — constitution mandates TDD (tests before implementation) and E2E for every frontend user story.

**Organization**: Tasks grouped by user story. Both stories are P1 but US2 depends on US1's backend work.

## Format: `[ID] [P?] [Story] Description`

- **[P]**: Can run in parallel (different files, no dependencies)
- **[Story]**: Which user story this task belongs to (e.g., US1, US2)
- Include exact file paths in descriptions

---

## Phase 1: Setup (Shared Infrastructure)

**Purpose**: OpenAPI spec, database migration, and domain model changes that both user stories depend on.

- [X] T001 Update OpenAPI spec with PATCH endpoint on `/events/{eventToken}` (organizerToken as query param), PatchEventRequest schema (`cancelled`, `cancellationReason`), and extend GetEventResponse with `cancelled`/`cancellationReason` fields in `backend/src/main/resources/openapi/api.yaml`
- [X] T002 Add Liquibase changeset 004 adding `cancelled` (BOOLEAN NOT NULL DEFAULT FALSE) and `cancellation_reason` (VARCHAR 2000) columns to `events` table in `backend/src/main/resources/db/changelog/004-add-cancellation-columns.xml` and register it in `db.changelog-master.xml`
- [X] T003 [P] Extend domain model `Event.java` with `cancelled`, `cancellationReason` fields and `cancel(String reason)` method (throws `EventAlreadyCancelledException`). Create `EventAlreadyCancelledException` in `backend/src/main/java/de/fete/domain/model/`. Domain model: `backend/src/main/java/de/fete/domain/model/Event.java`
- [X] T004 [P] Extend JPA entity `EventJpaEntity.java` with `cancelled` and `cancellation_reason` columns and update mapper in `backend/src/main/java/de/fete/adapter/out/persistence/EventPersistenceAdapter.java`
- [X] T005 Regenerate frontend TypeScript types from updated OpenAPI spec via `cd frontend && npm run generate:api`

**Checkpoint**: Schema, migration, and domain model ready. Both user stories can now proceed.

---

## Phase 2: User Story 1 — Organizer Cancels an Event (Priority: P1) MVP

**Goal**: Organizer can cancel an event via a bottom sheet with optional reason. Cancellation is irreversible and persists on reload.

**Independent Test**: View event with organizer token, tap cancel, optionally enter reason, confirm. Event remains cancelled on reload.

### Tests for User Story 1

> **Write these tests FIRST — ensure they FAIL before implementation**

- [X] ~~T006~~ Removed (EventTest.java unnecessary — cancel() tested via service/integration tests)
- [X] T007 [P] [US1] Write unit test for cancel use case in EventService (delegates to domain, saves, 403/404/409 cases) in `backend/src/test/java/de/fete/application/service/EventServiceCancelTest.java`
- [X] T008 [P] [US1] Write integration tests for `PATCH /events/{eventToken}` endpoint (204 success, 403 wrong token, 404 not found, 409 already cancelled) in `backend/src/test/java/de/fete/adapter/in/web/EventControllerIntegrationTest.java`
- [X] T009 [P] [US1] Write E2E test: organizer opens cancel bottom sheet, enters reason, confirms — event shows as cancelled on reload in `frontend/e2e/cancel-event.spec.ts`
- [X] T010 [P] [US1] Write E2E test: organizer cancels without reason — event shows as cancelled in `frontend/e2e/cancel-event.spec.ts`
- [X] T011 [P] [US1] Write E2E test: cancel API fails — error displayed in bottom sheet, button re-enabled for retry in `frontend/e2e/cancel-event.spec.ts`

### Implementation for User Story 1

- [X] T012 [US1] Create `UpdateEventUseCase` interface in `backend/src/main/java/de/fete/domain/port/in/UpdateEventUseCase.java`
- [X] T013 [US1] Implement cancel logic in `EventService.java` — load event, verify organizer token, call `event.cancel(reason)`, persist in `backend/src/main/java/de/fete/application/service/EventService.java`
- [X] T014 [US1] Implement `patchEvent` endpoint in `EventController.java` — PATCH handler, query param organizerToken, request body binding, error mapping (403/404/409) in `backend/src/main/java/de/fete/adapter/in/web/EventController.java`
- [X] T015 [US1] Add cancel button (visible only when organizer token exists and event not cancelled — covers FR-012) and cancel bottom sheet (textarea with 2000 char limit + confirm button + inline error) to `frontend/src/views/EventDetailView.vue`
- [X] T016 [US1] Wire cancel bottom sheet confirm action to `PATCH /events/{eventToken}` API call via openapi-fetch, handle success (reload event data) and error (show inline message, re-enable button) in `frontend/src/views/EventDetailView.vue`

**Checkpoint**: Organizer can cancel an event. All US1 acceptance scenarios pass.

---

## Phase 3: User Story 2 — Attendee Sees Cancelled Event (Priority: P1)

**Goal**: Visitors see a prominent red cancellation banner on cancelled events. RSVP buttons are hidden. All other event details remain visible.

**Independent Test**: View a cancelled event's detail page — banner visible (with reason if provided), RSVP buttons hidden, other details intact.

### Tests for User Story 2

> **Write these tests FIRST — ensure they FAIL before implementation**

- [X] ~~T017~~ Removed (RsvpServiceCancelledTest unnecessary — covered by integration test)
- [X] T018 [P] [US2] Write integration test for `POST /events/{eventToken}/rsvps` returning 409 when event is cancelled in `backend/src/test/java/de/fete/adapter/in/web/EventControllerIntegrationTest.java`
- [X] T019 [P] [US2] Write E2E test: visitor sees red banner with cancellation reason on cancelled event in `frontend/e2e/cancelled-event-visitor.spec.ts`
- [X] T020 [P] [US2] Write E2E test: visitor sees red banner without reason when no reason was provided in `frontend/e2e/cancelled-event-visitor.spec.ts`
- [X] T021 [P] [US2] Write E2E test: RSVP buttons hidden on cancelled event, other details remain visible in `frontend/e2e/cancelled-event-visitor.spec.ts`

### Implementation for User Story 2

- [X] T022 [US2] Add cancelled-event guard to RSVP creation — check `event.isCancelled()`, return 409 Conflict in `backend/src/main/java/de/fete/application/service/RsvpService.java`
- [X] T023 [US2] Add cancellation banner component/section (red, prominent, includes reason if present, WCAG AA contrast) to `frontend/src/views/EventDetailView.vue`
- [X] T024 [US2] Hide RSVP buttons (`RsvpBar` or equivalent) when `event.cancelled === true` in `frontend/src/views/EventDetailView.vue`
- [X] ~~T025~~ Merged into T015 (cancel button v-if already handles FR-012)

**Checkpoint**: Both user stories fully functional. All acceptance scenarios pass.

---

## Phase 4: Polish & Cross-Cutting Concerns

**Purpose**: Validation, edge cases, and final cleanup.

- [X] T026 Verify cancellationReason max length (2000 chars) is enforced at API level (OpenAPI `maxLength`), domain level in `Event.java`, and UI level (textarea maxlength/counter)
- [X] T027 Run full backend test suite (`cd backend && ./mvnw verify`) and fix any failures
- [X] T028 Run full frontend test suite (`cd frontend && npm run test:unit`) and fix any failures
- [X] T029 Run E2E tests (`cd frontend && npx playwright test`) and fix any failures
- [X] T030 Run backend checkstyle (`cd backend && ./mvnw checkstyle:check`) and fix violations