<!-- GSD:project-start source:PROJECT.md -->

## Project

**FamilySync**

FamilySync is a self-hosted, Dockerized family organization hub for a two-person household, modeled loosely on Skylight. It gives the family one unified, color-coded calendar and shared collaborative lists (groceries, gift ideas), reachable from a single low-friction React PWA — across a mixed Android/Fastmail and Apple ecosystem — built as one custom app on top of the family's existing paid Fastmail account. Email stays with members' existing mail clients and is out of scope.

**Core Value:** The household can see and co-edit one color-coded family calendar (shared + each member's personal) and shared lists from a single low-friction PWA — cross-ecosystem, no app store, no per-member calendar credential juggling.

### Constraints

- **Tech stack**: MariaDB for the database — PostgreSQL is not available in the stack
- **Tech stack**: Redis available (optional, for live list sync / push)
- **Infrastructure**: Unraid host running Docker + Docker Compose
- **Auth**: Authelia (already deployed) — OIDC/OAuth2 for the custom app; all members authenticate through it
- **Calendar backend**: Fastmail (paid, existing) is the single source for all calendars via JMAP/CalDAV
- **Frontend**: React PWA only — no React Native, no App Store
- **Networking**: Split-DNS internal domain, private IPs internally; public exposure via Pangolin/Newt tunnel, no open ports
- **UX**: Must be slick and low-friction for a non-technical Apple member — hard constraint, drives design tradeoffs
- **Scope**: No email features; no forking existing apps

<!-- GSD:project-end -->

<!-- GSD:stack-start source:research/STACK.md -->

## Technology Stack

## Recommended Stack

### Core Technologies

| Technology           | Version | Purpose                   | Why Recommended                                                                                                                                                             |
| -------------------- | ------- | ------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Node.js + TypeScript | 22 LTS  | Backend runtime           | First-class typing, same language as frontend, largest CalDAV/OIDC library ecosystem                                                                                        |
| Hono                 | 4.12.23 | HTTP framework            | Web-Standards-native, first-class TypeScript, built-in SSE helper, WebSocket via `@hono/node-server`; lighter than Express and better ergonomics than Fastify for this size |
| Drizzle ORM          | 0.45.2  | MariaDB query layer       | Type-safe SQL, zero runtime overhead, native `mysql2` driver support, schema-as-code migrations via `drizzle-kit`                                                           |
| mysql2               | 3.22.4  | MariaDB driver            | The only maintained native MariaDB/MySQL driver; Drizzle targets it explicitly                                                                                              |
| React 19             | 19.x    | PWA frontend              | Required by project; concurrent features, stable                                                                                                                            |
| Vite                 | 8.0.x   | Build tooling             | De-facto standard for React PWAs; fast HMR, native ESM                                                                                                                      |
| vite-plugin-pwa      | 1.3.0   | Service worker + manifest | Zero-config Workbox integration, handles install prompt, offline cache, background sync scaffolding                                                                         |

### Supporting Libraries

| Library               | Version | Purpose                          | When to Use                                                                                                                                   |
| --------------------- | ------- | -------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------- |
| tsdav                 | 2.2.2   | CalDAV client for Node.js        | All calendar reads and writes against Fastmail CalDAV endpoint; handles PROPFIND, REPORT, PUT, DELETE                                         |
| ical.js               | 2.2.1   | iCalendar (.ics) parsing         | Parse raw VCALENDAR/VEVENT payloads returned by tsdav; handles VTIMEZONE, RDATE, EXDATE                                                       |
| rrule                 | 2.8.1   | Recurrence rule expansion        | Expand RRULE strings into concrete event occurrences for the calendar view; ical.js's built-in expansion is less ergonomic for UI consumption |
| web-push              | 3.6.7   | Server-side VAPID push           | Generate VAPID keys, sign and dispatch push messages to browser push services (APNs for iOS, FCM for Android)                                 |
| @hono/oidc-auth       | 1.8.3   | OIDC session middleware for Hono | Storage-less JWT session cookies; authorization-code + PKCE flow; works with any RFC-compliant OIDC provider including Authelia               |
| openid-client         | 6.8.4   | Low-level OIDC primitives        | If `@hono/oidc-auth` proves insufficient (e.g., custom token introspection), use this as the lower-level escape hatch                         |
| ioredis               | 5.11.0  | Redis client                     | Pub/sub for broadcasting list-change events to SSE connections across Node processes                                                          |
| zod                   | 3.24.x  | Schema validation                | Validate API request bodies and CalDAV event payloads before writing back to Fastmail                                                         |
| @hono/zod-validator   | 0.8.0   | Hono middleware for Zod          | Validate request body/query in route handlers with Zod schemas                                                                                |
| @tanstack/react-query | 5.101.0 | Server state + caching           | Manages calendar and list data fetching, background refetch, stale-while-revalidate; pairs with SSE for live list updates                     |
| zustand               | 5.0.14  | Client state                     | UI-only state (selected date range, color assignments, drawer open/closed); keep server state in React Query                                  |
| drizzle-kit           | 0.31.10 | Schema migrations                | Generates and runs MariaDB migrations from Drizzle schema definitions                                                                         |

### Development Tools

| Tool              | Purpose                                 | Notes                                                                          |
| ----------------- | --------------------------------------- | ------------------------------------------------------------------------------ |
| TypeScript 5.x    | Strict typing across backend + frontend | `strict: true`; share types between packages via a `packages/shared` workspace |
| ESLint + Prettier | Lint + format                           | Standard config; no bikeshedding needed                                        |
| Docker Compose    | Local dev + production parity           | Match Unraid stack exactly in dev                                              |
| Vitest            | Unit + integration tests                | Vite-native, same config as frontend                                           |

## Installation

# Backend

# Frontend

# Dev

## Calendar Integration: CalDAV, Not JMAP

- Principal URL: `https://caldav.fastmail.com/dav/principals/user/broker@fastmail.com/`
- `tsdav` performs `PROPFIND` on the principal to discover all calendar collections, then fetches each collection's events via `REPORT` (calendar-query or calendar-multiget).
- One app password covers all calendars owned by that account under the default "Mail, Contacts & Calendars" scope.
- `tsdav` returns raw iCalendar strings. Pass each to `ical.js` for parsing into event objects, then use `rrule` for RRULE expansion into the date range the UI needs.
- Write-back (create/edit/delete): PUT a new `.ics` to the collection URL; DELETE by UID.
- `node-ical`: older fork with weaker RRULE support; ical.js is maintained by Mozilla and is the reference implementation
- Direct `fetch`/`axios` against CalDAV: re-inventing XML namespace handling and PROPFIND parsing; tsdav exists specifically to avoid this
- JMAP: not available for calendars on Fastmail today

## Backend Framework

- First-class TypeScript with RPC-style type sharing (Hono RPC can export typed client for the React frontend — eliminates API drift)
- Built-in SSE streaming helper (`streamSSE`) for live list updates
- WebSocket support via `@hono/node-server`
- Runs on Node.js 22 LTS in Docker with `@hono/node-server`
- Prisma generates a binary engine that adds complexity in Docker images and has weaker MariaDB compatibility signals
- Drizzle uses `mysql2` directly — the same driver you'd use raw; no runtime translation layer
- Drizzle's `mysqlTable` schema is fully MariaDB-compatible (MariaDB is wire-compatible with MySQL; Drizzle's `mysql` dialect works)
- Type inference from schema → query results is the core value proposition; zero runtime overhead

## React PWA Stack

- TanStack Query owns all server-side state: calendar events, lists, user profile. It handles background refetch, cache invalidation, and loading states. Use `queryClient.invalidateQueries` from SSE event handlers to keep list data live.
- Zustand owns pure UI state: selected month, color assignments per calendar, drawer states. Do not put server data in Zustand.

| Requirement           | Detail                                                                                 |
| --------------------- | -------------------------------------------------------------------------------------- |
| Minimum iOS version   | 16.4 — push is silently unavailable on earlier versions                                |
| Installation required | PWA **must** be added to Home Screen; push does not work from Safari browser tabs      |
| User gesture          | `pushManager.subscribe()` must be called inside a tap handler, not on page load        |
| EU users on iOS 17.4+ | PWAs may open in Safari tabs instead of standalone mode due to DMA; affects push reach |
| Silent push           | Not supported on iOS; all push messages must display a visible notification            |
| Background sync       | Not supported on iOS; no `BackgroundSync` or `PeriodicBackgroundSync`                  |

## Authelia OIDC Integration

- `response_types: [code]`
- `grant_types: [authorization_code, refresh_token]`
- `require_pkce: true`, `pkce_challenge_method: S256`
- `token_endpoint_auth_method: client_secret_basic`

## Live List Sync

## Alternatives Considered

| Recommended     | Alternative            | Why Not                                                                                           |
| --------------- | ---------------------- | ------------------------------------------------------------------------------------------------- |
| Hono            | Express                | No native TypeScript ergonomics; no built-in SSE; larger ecosystem but more boilerplate           |
| Hono            | Fastify                | Good choice but heavier plugin model; Hono's Web Standards alignment is better for this size      |
| Drizzle         | Prisma                 | Binary engine complicates Docker; weaker explicit MariaDB support; heavier                        |
| tsdav           | Raw fetch + xml2js     | CalDAV XML namespace handling is tedious; tsdav is the established TypeScript CalDAV client       |
| ical.js         | node-ical              | node-ical is a fork that has diverged; ical.js is the Mozilla-maintained reference implementation |
| @hono/oidc-auth | express-openid-connect | express-openid-connect is Express-specific; Hono middleware is the correct fit                    |
| SSE             | WebSockets             | WebSockets are bidirectional; list sync is server→client only; SSE is simpler and proxy-friendly  |
| CalDAV          | JMAP                   | JMAP calendars not available on Fastmail as of 2026                                               |

## What NOT to Use

| Avoid                       | Why                                                              | Use Instead      |
| --------------------------- | ---------------------------------------------------------------- | ---------------- |
| JMAP for calendars          | Not implemented by Fastmail; spec not finalized                  | CalDAV via tsdav |
| Prisma                      | Binary engine, weaker MariaDB compat, larger footprint in Docker | Drizzle ORM      |
| oidc-client-ts              | Browser-side OIDC library; wrong layer for a backend-session app | @hono/oidc-auth  |
| node-ical                   | Older fork of ical.js, less maintained, weaker RRULE handling    | ical.js          |
| Create React App            | Deprecated February 2025                                         | Vite             |
| PostgreSQL                  | Not in the Unraid stack; hard constraint                         | MariaDB          |
| NestJS                      | Massive framework overhead for a two-user household app          | Hono             |
| Firebase/FCM as push broker | Third-party dependency; VAPID direct push works without it       | web-push (VAPID) |

## Version Compatibility

| Package               | Compatible With        | Notes                                                                                      |
| --------------------- | ---------------------- | ------------------------------------------------------------------------------------------ |
| drizzle-orm@0.45.x    | mysql2@3.x             | Use `drizzle-orm/mysql2` import path; mysql2@3.x uses Promises API by default              |
| vite-plugin-pwa@1.3.x | Vite@8.x, Workbox@7.x  | vite-plugin-pwa 0.16+ requires Node 16+; 1.x tracks Vite 6+                                |
| @hono/oidc-auth@1.8.x | hono@4.x, oauth4webapi | Peer-depends on hono 4.x                                                                   |
| ical.js@2.x           | rrule@2.8.x            | Use together: ical.js parses the RRULE string, pass to `new RRule(RRule.parseString(...))` |
| web-push@3.6.x        | Node.js 18+            | VAPID uses Web Crypto; works in Node.js 18+ natively                                       |

## Open Questions Flagged for Phase Research

## Sources

- [Fastmail API Documentation](https://www.fastmail.com/dev/) — Confirmed CalDAV-only for calendars; JMAP calendars not available
- [Fastmail App Passwords](https://www.fastmail.help/hc/en-us/articles/360058752854-App-passwords) — Scope covers CalDAV; single password covers all calendars in account
- [Using Fastmail with CalDAV libraries](https://utf9k.net/blog/fastmail-caldav/) — Principal URL pattern, app password auth
- [Fastmail Calendar Sharing](https://www.fastmail.help/hc/en-us/articles/1500000279781-Sharing-calendars-with-other-users) — Sharing is multi-user-account scoped; cross-account sharing unconfirmed
- [tsdav npm](https://www.npmjs.com/package/tsdav) — Version 2.2.2 confirmed
- [ical.js npm](https://www.npmjs.com/package/ical.js) — Version 2.2.1 confirmed; Mozilla-maintained
- [rrule npm](https://www.npmjs.com/package/rrule) — Version 2.8.1 confirmed
- [Hono](https://hono.dev/) — Version 4.12.23; Node.js adapter confirmed
- [Drizzle ORM MySQL](https://orm.drizzle.team/docs/get-started-mysql) — MariaDB via mysql2 confirmed
- [vite-plugin-pwa](https://vite-pwa-org.netlify.app/) — Version 1.3.0; Workbox 7 integration
- [web-push npm](https://www.npmjs.com/package/web-push) — Version 3.6.7
- [Meet Declarative Web Push — WebKit](https://webkit.org/blog/16535/meet-declarative-web-push/) — Safari 18.4+, iOS 18.4+ confirmed
- [PWA iOS Limitations 2026](https://www.magicbell.com/blog/pwa-ios-limitations-safari-support-complete-guide) — iOS 16.4 minimum; home screen required; EU DMA regression
- [Authelia Express.js Integration](https://www.authelia.com/integration/openid-connect/clients/expressjs/) — Authorization code + PKCE flow; client_secret_basic
- [@hono/oidc-auth GitHub](https://github.com/honojs/middleware/tree/main/packages/oidc-auth) — Storage-less JWT session cookies; Version 1.8.3

<!-- GSD:stack-end -->

<!-- GSD:conventions-start source:CONVENTIONS.md -->

## Conventions

### Browser-based verification

- **Use the `playwright-cli` skill (`.claude/skills/playwright-cli/`) to validate UI and workflows instead of asking the operator to check manually.** When a change touches the PWA, or a UI/UX decision needs grounding in real behavior, drive a real browser with `playwright-cli` and observe — don't prompt the human to do it. This applies to executors and verifiers too: prefer an automated `playwright-cli` check over a `checkpoint:human-verify` task whenever the check runs in a desktop/Chromium browser.
- **Exception — genuinely device-only checks still need a human.** iOS-Safari standalone-PWA behavior (Home-Screen install, standalone-mode OIDC redirect, iOS push) cannot be driven by `playwright-cli`; keep those as human checkpoints (e.g. Phase 3 Gate 2 iOS items).
- The `playwright-cli` binary is global (`/usr/local/bin/playwright-cli`). `@playwright/test` is not a repo dependency — install it in `apps/pwa` only if you need the spec-driven test-generation references.
<!-- GSD:conventions-end -->

<!-- GSD:architecture-start source:ARCHITECTURE.md -->

## Architecture

Architecture not yet mapped. Follow existing patterns found in the codebase.

<!-- GSD:architecture-end -->

<!-- GSD:skills-start source:skills/ -->

## Project Skills

No project skills found. Add skills to any of: `.claude/skills/`, `.agents/skills/`, `.cursor/skills/`, `.github/skills/`, or `.codex/skills/` with a `SKILL.md` index file.

<!-- GSD:skills-end -->

<!-- GSD:workflow-start source:GSD defaults -->

## GSD Workflow Enforcement

Before using Edit, Write, or other file-changing tools, start work through a GSD command so planning artifacts and execution context stay in sync.

Use these entry points:

- `/gsd-quick` for small fixes, doc updates, and ad-hoc tasks
- `/gsd-debug` for investigation and bug fixing
- `/gsd-execute-phase` for planned phase work

Do not make direct repo edits outside a GSD workflow unless the user explicitly asks to bypass it.

<!-- GSD:workflow-end -->

<!-- GSD:profile-start -->

## Developer Profile

> Profile not yet configured. Run `/gsd-profile-user` to generate your developer profile.
> This section is managed by `generate-claude-profile` -- do not edit manually.

<!-- GSD:profile-end -->
