spotiarr-architecture

name	spotiarr-architecture
description	Trigger: architecture, layer, placement, where does X go, new feature, repo structure. spotiarr layer rules: backend DDD-lite, frontend hooks/store/views.
license	Apache-2.0
metadata	{"author":"gentleman-programming","version":"2.0"}

Activation Contract

Load when deciding where new code belongs across backend, frontend, or shared.

Hard Rules

• Dependencies point inward: presentation → application → domain; infrastructure implements inner-layer contracts — never the reverse.
• Prisma, Redis, yt-dlp, external HTTP → infrastructure/ only. Never in domain/ or presentation/.
• All use-cases and services register at: apps/backend/src/container.ts (NOT in infrastructure/ — it's at src/ root).
• Server state in frontend → TanStack Query (hooks/queries, hooks/mutations). Client state → Zustand slices under store/ (one file per domain).
• Real-time SSE sync → useServerEvents hook. Do not add manual SSE subscriptions elsewhere.
• Shared DTOs, enums, utilities → packages/shared/. Never duplicate in apps.
• All Spotify HTTP calls must go through CircuitBreaker.execute() (infrastructure/external/circuit-breaker.ts). Never add a raw Spotify HTTP call without wrapping it. The circuit persists open state via onOpen callback → settings → restored on restart.

Decision Gates

Backend — where does it go?
  Business rule / invariant?         → domain/
  Use-case orchestration?            → application/
  DB, queues, APIs, filesystem?      → infrastructure/
  HTTP routes, controllers, SSE?     → presentation/
  Cross-cutting request guards?      → presentation/middleware/

Frontend — where does it go?
  UI rendering / composition?        → components/
  Page-level screens?                → views/
  View logic / orchestration?        → hooks/
  Remote fetch / mutate?             → services/ + hooks/queries|mutations
  App-wide client state?             → store/
  Ephemeral gate/overlay state?      → local useState in the controller hook (NOT a Zustand store; see useTokenGate)

Cross-cutting types / utils?         → packages/shared/

References

• DI container: apps/backend/src/container.ts
• Store pattern: apps/frontend/src/store/
• Request guards: apps/backend/src/presentation/middleware/
• Auth gate hook: apps/frontend/src/hooks/controllers/useTokenGate.ts