---
phase: 18-auto-timezone-detection-and-ability-to-change-timezone
plan: "02"
subsystem: api
tags: [timezone, iana, drizzle, vitest, tdd, admin, hono]

# Dependency graph
requires:
  - phase: 18-01
    provides: isValidIanaTimezone + getHouseholdTimezone (consumed by timezoneSchema + GET handler)
  - phase: 10-admin-role-settings
    provides: adminRouter + requireAdmin + appConfig table

provides:
  - GET /api/admin/config/timezone — reads stored household timezone with isExplicitlySet flag
  - PUT /api/admin/config/timezone — validates IANA string + upserts household_timezone in app_config
  - POST /api/admin/config/timezone/seed — seeds only when unset (D-03 no-overwrite)

affects:
  - 18-03-PLAN (broker rewire — reminderScheduler + outboxWorker import getHouseholdTimezone)
  - 18-04-PLAN (PWA settings UI — consumes GET + PUT endpoints built here)

# Tech tracking
tech-stack:
  added: []
  patterns:
    - zValidator('json', schema) without noEchoHook for non-sensitive config (timezone is not a credential)
    - Drizzle onDuplicateKeyUpdate upsert for config PUT (appConfig PK = key)
    - SELECT-before-INSERT pattern for no-overwrite seed (D-03 — DO NOT use onDuplicateKeyUpdate for seed)
    - requireAdmin positional coverage: new routes appended after line-41 adminRouter.use('*', requireAdmin)

key-files:
  created: []
  modified:
    - apps/api/src/routes/admin.ts
    - apps/api/tests/routes/admin.test.ts

key-decisions:
  - "timezoneSchema uses isValidIanaTimezone (from 18-01) in Zod .refine() — no noEchoHook needed (T-18-06: timezone is non-sensitive)"
  - "GET /config/timezone reads row directly (not via getHouseholdTimezone) to compute isExplicitlySet from row?.value != null, then uses getHouseholdTimezone for the fallback value"
  - "seed endpoint uses SELECT-then-INSERT (not onDuplicateKeyUpdate) to ensure D-03 no-overwrite is an explicit code path, not a silent race"

requirements-completed: [D-01, D-02, D-03, D-04]

# Metrics
duration: 3min
completed: 2026-06-15
---

# Phase 18 Plan 02: Admin Timezone API Endpoints Summary

**Three role-gated admin endpoints (GET + PUT + seed) added to adminRouter with server-side IANA validation via isValidIanaTimezone and D-03 no-overwrite seed semantics enforced by SELECT-before-INSERT**

## Performance

- **Duration:** 3 min
- **Started:** 2026-06-15T02:09:38Z
- **Completed:** 2026-06-15T02:12:39Z
- **Tasks:** 2 (TDD RED + GREEN)
- **Files modified:** 2

## Accomplishments

- Added `describe('admin timezone config')` to `admin.test.ts` with 8 test cases covering all boundary conditions
- Implemented `GET /api/admin/config/timezone`, `PUT /api/admin/config/timezone`, and `POST /api/admin/config/timezone/seed` on the existing `adminRouter`
- All routes inherit the line-41 `requireAdmin` guard (Pitfall 9 / T-18-03) — no per-route auth addition needed
- `timezoneSchema` uses `isValidIanaTimezone` from Plan 18-01 in a Zod `.refine()` — no `noEchoHook` (T-18-06)
- `PUT` uses `onDuplicateKeyUpdate` for a true upsert; `seed` uses SELECT-then-INSERT to enforce D-03 no-overwrite
- 25/25 `admin.test.ts` tests pass; 366/366 full API suite green; `tsc --noEmit` clean

## Task Commits

1. **Task 1: RED — failing integration tests** - `f109b3c` (test)
2. **Task 2: GREEN — implement GET/PUT/seed timezone endpoints** - `3bd6a5d` (feat)

## Files Created/Modified

- `apps/api/src/routes/admin.ts` — added appConfig + householdTimezone imports, timezoneSchema, and three new route handlers
- `apps/api/tests/routes/admin.test.ts` — added appConfig import + `describe('admin timezone config')` with 8 test cases + per-test afterEach cleanup

## Decisions Made

- `timezoneSchema` does NOT use `noEchoHook` because timezone strings are non-sensitive (not credentials/PII); standard `zValidator` error responses are safe (T-18-06 accepted disposition).
- `GET /config/timezone` does a direct single-row read (not `getHouseholdTimezone`) so the handler can compute `isExplicitlySet` from `row?.value != null` before deciding whether to invoke the fallback chain — using `getHouseholdTimezone` would discard the "was it stored?" signal.
- `POST /api/admin/config/timezone/seed` uses a SELECT-then-INSERT (not `onDuplicateKeyUpdate`) so that D-03 no-overwrite is an explicit code branch, not an implicit race. The test asserts the stored value after a second seed attempt remains unchanged.

## Deviations from Plan

None — plan executed exactly as written.

## Issues Encountered

- Running `pnpm --filter @familysync/api exec vitest run` requires `DB_ROOT_PASSWORD` from `.env` sourced into the shell (the global-setup provisions `familysync_test` using the root credential). This is the established pattern from quick 260613-ndv and documented in `familysync-dev-stack-setup.md`.

## Known Stubs

None — all three endpoints are fully wired to the database. No placeholder data.

## Threat Flags

No new threat surface beyond the plan's threat model. All three endpoints are behind `requireAdmin` (T-18-03). IANA validation enforced by `isValidIanaTimezone` (T-18-04). No SQL injection surface — key is a hard-coded literal, value is IANA-validated, Drizzle parameterizes the insert/upsert (T-18-07).

## TDD Gate Compliance

- RED gate: `f109b3c` — `test(18-02): add failing integration tests for admin timezone endpoints`
- GREEN gate: `3bd6a5d` — `feat(18-02): admin timezone GET/PUT/seed endpoints`
- REFACTOR gate: N/A (implementation was clean on first pass)

## Next Phase Readiness

- Plan 18-03 (broker rewire) can import `getHouseholdTimezone(db)` from `../lib/householdTimezone.js` to replace the bare `process.env.TZ ?? Intl…` lookups in `reminderScheduler.ts:247` and `outboxWorker.ts:501,607`.
- Plan 18-04 (PWA settings UI) can wire to `GET /api/admin/config/timezone` and `PUT /api/admin/config/timezone`. The seed endpoint is also available for the Phase 12 wizard auto-detect flow.

## Self-Check: PASSED

- `apps/api/src/routes/admin.ts` — FOUND (modified)
- `apps/api/tests/routes/admin.test.ts` — FOUND (modified)
- Commit `f109b3c` — FOUND
- Commit `3bd6a5d` — FOUND

---
*Phase: 18-auto-timezone-detection-and-ability-to-change-timezone*
*Completed: 2026-06-15*
