Resume the last garden on this device (#97)

`/` always dumped you on the gardens list; a phone user who lives in one
garden had to open the list and tap in every time. Now the device
remembers the garden it was last in and `/` resumes there.

- lib/lastGarden.ts: per-device localStorage (pansy:last-garden), same
  swallow-failures rationale as the seed tray / recents. getLastGardenId
  guards against a non-positive/garbage stored value.
- The `/` route redirects to the stored garden when present, else /gardens.
- The editor records the garden on successful load, and — if it 404s
  (deleted or access revoked) — forgets it (only if it's the stored one,
  so a bad direct link can't wipe a good resume target) and bounces to the
  list, so a stale id can't trap the user on an error screen. Transient
  errors still show the retryable message.
- ApiError.isNotFound getter (mirrors isConflict/isUnauthorized).

Verified live at 390px: resume into the last garden; a stale id bounces to
/gardens and clears itself. tsc + vitest (incl. new lastGarden test) green.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01H3zbym8Doka2d7D48maSgZ

web/src/lib/api.ts

@@ -30,6 +30,11 @@ export class ApiError extends Error {
   get isUnauthorized(): boolean {
     return this.status === 401
   }
+
+  /** Resource is gone or masked (pansy returns 404 for no-access, not 403). */
+  get isNotFound(): boolean {
+    return this.status === 404
+  }
 }
 
 type ParamValue = string | number | boolean | undefined | null

web/src/lib/lastGarden.test.ts

@@ -0,0 +1,70 @@
+import { afterEach, beforeEach, describe, expect, it } from 'vitest'
+import { getLastGardenId, rememberLastGarden, forgetLastGarden } from './lastGarden'
+
+// The tests run in the node environment (no DOM), so stand up a minimal
+// in-memory localStorage rather than pull in jsdom for one thin module.
+function installStorage(impl?: Partial<Storage>) {
+  const store = new Map<string, string>()
+  const base: Storage = {
+    getItem: (k) => store.get(k) ?? null,
+    setItem: (k, v) => void store.set(k, String(v)),
+    removeItem: (k) => void store.delete(k),
+    clear: () => store.clear(),
+    key: (i) => [...store.keys()][i] ?? null,
+    get length() {
+      return store.size
+    },
+  }
+  ;(globalThis as { localStorage?: Storage }).localStorage = { ...base, ...impl }
+}
+
+beforeEach(() => installStorage())
+afterEach(() => {
+  delete (globalThis as { localStorage?: Storage }).localStorage
+})
+
+describe('lastGarden', () => {
+  it('round-trips a remembered garden id', () => {
+    expect(getLastGardenId()).toBeNull()
+    rememberLastGarden(42)
+    expect(getLastGardenId()).toBe(42)
+  })
+
+  it('rejects a non-positive or unparseable stored value', () => {
+    localStorage.setItem('pansy:last-garden', 'not-a-number')
+    expect(getLastGardenId()).toBeNull()
+    localStorage.setItem('pansy:last-garden', '0')
+    expect(getLastGardenId()).toBeNull()
+    localStorage.setItem('pansy:last-garden', '-3')
+    expect(getLastGardenId()).toBeNull()
+  })
+
+  it('forgets unconditionally with no argument', () => {
+    rememberLastGarden(7)
+    forgetLastGarden()
+    expect(getLastGardenId()).toBeNull()
+  })
+
+  it('forgets only when the stored id matches onlyIfEquals', () => {
+    rememberLastGarden(5)
+    // A 404 on a different (directly-linked) garden must not wipe the good resume.
+    forgetLastGarden(9)
+    expect(getLastGardenId()).toBe(5)
+    // A 404 on the stored garden itself does clear it.
+    forgetLastGarden(5)
+    expect(getLastGardenId()).toBeNull()
+  })
+
+  it('swallows storage failures instead of throwing', () => {
+    installStorage({
+      setItem: () => {
+        throw new Error('quota')
+      },
+      getItem: () => {
+        throw new Error('blocked')
+      },
+    })
+    expect(() => rememberLastGarden(1)).not.toThrow()
+    expect(getLastGardenId()).toBeNull() // getItem throwing → null, not a crash
+  })
+})

web/src/lib/lastGarden.ts

@@ -0,0 +1,46 @@
+// The last garden opened on THIS device, so a returning user resumes where they
+// were instead of always landing on the gardens list. Per-device, in
+// localStorage (same rationale as the seed tray and PlantPicker recents): a
+// convenience, not authoritative state — a quota/availability failure is
+// swallowed, and a stored id that no longer loads clears itself (see the editor).
+//
+// Only the id is stored. The garden is resolved by the editor on load; if it's
+// gone (deleted, or access revoked), forgetLastGarden() drops it so `/` stops
+// resuming a garden that can't open.
+
+const KEY = 'pansy:last-garden'
+
+/** The last-opened garden id on this device, or null if none/unparseable. */
+export function getLastGardenId(): number | null {
+  try {
+    const raw = localStorage.getItem(KEY)
+    if (raw == null) return null
+    const n = Number(raw)
+    return Number.isInteger(n) && n > 0 ? n : null
+  } catch {
+    return null
+  }
+}
+
+/** Record the garden the device is now in, so `/` resumes here next time. */
+export function rememberLastGarden(id: number): void {
+  try {
+    localStorage.setItem(KEY, String(id))
+  } catch {
+    // Resume is a convenience; ignore quota/availability failures.
+  }
+}
+
+/**
+ * Forget the stored last garden. With `onlyIfEquals`, clears only when the stored
+ * id matches — so a 404 on a directly-linked garden can't wipe a different, still
+ * good resume target the user had.
+ */
+export function forgetLastGarden(onlyIfEquals?: number): void {
+  try {
+    if (onlyIfEquals != null && getLastGardenId() !== onlyIfEquals) return
+    localStorage.removeItem(KEY)
+  } catch {
+    // ignore
+  }
+}

web/src/pages/GardenEditorPage.tsx

@@ -36,6 +36,8 @@ import { useJournalCounts } from '@/lib/journal'
 import { attributableLots, lotsByPlant, useSeedLots, type SeedLot } from '@/lib/seedLots'
 import { useSeedTray } from '@/lib/seedTray'
 import { usePageTitle } from '@/lib/usePageTitle'
+import { rememberLastGarden, forgetLastGarden } from '@/lib/lastGarden'
+import { ApiError } from '@/lib/api'
 
 const routeApi = getRouteApi('/gardens/$gardenId')
 
@@ -133,6 +135,24 @@ export function GardenEditorPage() {
     navigate({ search: (prev) => ({ ...prev, focus: focusedObjectId ?? undefined }), replace: true })
   }, [focusedObjectId, navigate])
 
+  // Remember this garden as the device's last-opened, so `/` resumes here next
+  // visit. Keyed on the live query: which garden EXISTS doesn't depend on the
+  // season being viewed.
+  useEffect(() => {
+    if (live.isSuccess) rememberLastGarden(gid)
+  }, [live.isSuccess, gid])
+
+  // A last garden that 404s (deleted, or access revoked) must not strand the user
+  // on an error screen the `/` resume keeps returning to: forget it (only if it's
+  // this one, so a bad direct link can't wipe a good resume target) and bounce to
+  // the list. Transient errors (500/network) fall through to the retryable screen.
+  useEffect(() => {
+    if (live.isError && live.error instanceof ApiError && live.error.isNotFound) {
+      forgetLastGarden(gid)
+      navigate({ to: '/gardens' })
+    }
+  }, [live.isError, live.error, gid, navigate])
+
   // If the focused object vanished — deleted, or a stale ?focus id on load — leave
   // focus mode so the canvas isn't stuck dimmed with no way out.
   useEffect(() => {
@@ -256,12 +276,20 @@ export function GardenEditorPage() {
   }, [])
 
   if (full.isPending) return <p className="p-6 text-sm text-muted">Loading garden…</p>
-  if (full.isError)
+  if (full.isError) {
+    // A not-found is handled by the effect above (forget + bounce to the list);
+    // say so rather than flashing a dead-end error during the redirect.
+    const gone = full.error instanceof ApiError && full.error.isNotFound
     return (
       <div className="p-6">
-        <Alert>Could not load this garden.</Alert>
+        <Alert>
+          {gone
+            ? 'That garden is no longer available — taking you to your gardens…'
+            : 'Could not load this garden.'}
+        </Alert>
       </div>
     )
+  }
 
   const g = full.data.garden
   const garden: EditorGarden = {

web/src/router.tsx

@@ -18,6 +18,7 @@ import { SettingsPage } from '@/pages/SettingsPage'
 import { meQueryOptions } from '@/lib/auth'
 import { queryClient } from '@/lib/queryClient'
 import { safeRedirectPath } from '@/lib/redirect'
+import { getLastGardenId } from '@/lib/lastGarden'
 
 interface RouterContext {
   queryClient: QueryClient
@@ -66,7 +67,15 @@ async function requireAdmin(context: RouterContext, path: string) {
 const indexRoute = createRoute({
   getParentRoute: () => rootRoute,
   path: '/',
+  // Resume the garden this device was last in, so a returning user lands back in
+  // their plot rather than on the list every time. A stored id that no longer
+  // loads is cleared by the editor and bounces here to /gardens on the next
+  // visit, so this can't trap anyone on a dead garden.
   beforeLoad: () => {
+    const last = getLastGardenId()
+    if (last != null) {
+      throw redirect({ to: '/gardens/$gardenId', params: { gardenId: String(last) } })
+    }
     throw redirect({ to: '/gardens' })
   },
 })