fete/specs/016-cancel-event/plan.md

Implementation Plan: Cancel Event

Branch: 016-cancel-event | Date: 2026-03-12 | Spec: spec.md Input: Feature specification from /specs/016-cancel-event/spec.md

Summary

Allow organizers to permanently cancel events via a bottom sheet UI. Cancelled events display a red banner to visitors and block new RSVPs. Implementation adds a PATCH /events/{eventToken} endpoint, extends the Event entity with cancelled and cancellationReason fields, and reuses the existing BottomSheet.vue component for the cancel interaction.

Technical Context

Language/Version: Java 25 (backend), TypeScript 5.9 (frontend) Primary Dependencies: Spring Boot 3.5.x, Vue 3, Vue Router 5, openapi-fetch, openapi-typescript Storage: PostgreSQL (JPA via Spring Data, Liquibase migrations) Testing: JUnit (backend), Vitest (frontend unit), Playwright + MSW (frontend E2E) Target Platform: Self-hosted Linux server, mobile-first PWA Project Type: Web application (REST API + SPA) Performance Goals: N/A — simple state transition, no performance-critical path Constraints: Privacy by design (no analytics/tracking), WCAG AA, mobile-first Scale/Scope: Single new endpoint, 2 new DB columns, 1 view extension

Constitution Check

GATE: Must pass before Phase 0 research. Re-check after Phase 1 design.

Principle	Status	Notes
I. Privacy by Design	PASS	No new data collection beyond organizer-provided reason. No analytics.
II. Test-Driven Methodology	PASS	TDD enforced: tests before implementation, E2E mandatory for both user stories.
III. API-First Development	PASS	OpenAPI spec updated first, types generated before implementation. example: fields included.
IV. Simplicity & Quality	PASS	Minimal change: 2 columns, 1 endpoint, reuse existing BottomSheet. No over-engineering.
V. Dependency Discipline	PASS	No new dependencies required.
VI. Accessibility	PASS	Reuses accessible BottomSheet component. Banner uses semantic HTML + ARIA.

Gate result: PASS — no violations.

Project Structure

Documentation (this feature)

specs/016-cancel-event/
├── plan.md              # This file
├── spec.md              # Feature specification
├── research.md          # Phase 0 output — design decisions
├── data-model.md        # Phase 1 output — entity changes
├── quickstart.md        # Phase 1 output — implementation overview
├── contracts/           # Phase 1 output — API contract additions
│   └── patch-event-endpoint.yaml
└── tasks.md             # Phase 2 output (/speckit.tasks command)

Source Code (repository root)

backend/
├── src/main/java/de/fete/
│   ├── domain/model/Event.java                          # + cancelled, cancellationReason, cancel()
│   ├── application/service/EventService.java            # + CancelEventUseCase implementation
│   ├── adapter/in/web/EventController.java              # + cancelEvent endpoint
│   └── adapter/out/persistence/
│       ├── EventJpaEntity.java                          # + cancelled, cancellation_reason columns
│       └── EventPersistenceAdapter.java                 # + mapper updates
├── src/main/resources/
│   ├── openapi/api.yaml                                 # + cancel endpoint, request/response schemas
│   └── db/changelog/004-add-cancellation-columns.xml    # New migration
└── src/test/java/de/fete/                               # Unit + integration tests

frontend/
├── src/
│   └── views/EventDetailView.vue                        # + cancel button, bottom sheet, banner
└── e2e/                                                 # E2E tests for both user stories

Structure Decision: Web application (Option 2) — matches existing project layout with backend/ and frontend/ at repository root.

Complexity Tracking

No violations — table not applicable.