fix(transactions): persist the source filter per company and stop the reset race (#1726)

The source filter was persisted under a browser-wide v1 key (#1105), but
the stale-filter guard added in #1124 compared the restored value against
sourceItems before cash accounts, skattekonto rows, and transactions had
loaded, so every mount reset the in-memory filter back to 'Alla källor'
while storage kept the old choice: restore-then-reset on every visit.

- New pure helper components/transactions/source-filter-storage.ts:
  per-company v2 key, isSourceFilter moved out of the page, read/write
  helpers (read removes the retired v1 key once), and
  resolveEffectiveSourceFilter.
- page.tsx keeps sourceFilter as the WANTED filter, restored per company
  (with a state-only ?source= URL override that is never written to
  storage); the guard effect is replaced by a derived
  effectiveSourceFilter memo used by every consumer, so a source that is
  still loading or went stale shows 'all' without destroying the choice.
- ?highlight= deep links widen to 'all' in memory when the wanted filter
  would hide the highlighted row.
- Unit tests for the helper; no i18n changes, no migrations.

Co-authored-by: Jakob Wennberg <311770904+jakobwennberg-oss@users.noreply.github.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

components/transactions/__tests__/source-filter-storage.test.ts

@@ -0,0 +1,122 @@
+import { describe, it, expect, vi, afterEach } from 'vitest'
+import {
+  SOURCE_FILTER_STORAGE_PREFIX,
+  isSourceFilter,
+  readStoredSourceFilter,
+  writeStoredSourceFilter,
+  resolveEffectiveSourceFilter,
+} from '@/components/transactions/source-filter-storage'
+
+const LEGACY_KEY = 'Accounted:transaction-source-filter:v1'
+
+function stubLocalStorage(initial: Record<string, string> = {}) {
+  const store = new Map<string, string>(Object.entries(initial))
+  const localStorage = {
+    getItem: (key: string) => store.get(key) ?? null,
+    setItem: (key: string, value: string) => {
+      store.set(key, value)
+    },
+    removeItem: (key: string) => {
+      store.delete(key)
+    },
+  }
+  vi.stubGlobal('window', { localStorage })
+  return store
+}
+
+afterEach(() => {
+  vi.unstubAllGlobals()
+})
+
+describe('isSourceFilter', () => {
+  it('accepts every member of the SourceFilter union', () => {
+    expect(isSourceFilter('all')).toBe(true)
+    expect(isSourceFilter('bank')).toBe(true)
+    expect(isSourceFilter('bank:other')).toBe(true)
+    expect(isSourceFilter('skatteverket')).toBe(true)
+    expect(isSourceFilter('acct:2f8d1c3a')).toBe(true)
+  })
+
+  it('rejects null and unknown values', () => {
+    expect(isSourceFilter(null)).toBe(false)
+    expect(isSourceFilter('')).toBe(false)
+    expect(isSourceFilter('everything')).toBe(false)
+    expect(isSourceFilter('account:123')).toBe(false)
+    expect(isSourceFilter('ALL')).toBe(false)
+  })
+})
+
+describe('resolveEffectiveSourceFilter', () => {
+  it('keeps the wanted filter when its id is among the items', () => {
+    expect(resolveEffectiveSourceFilter('acct:a1', ['all', 'acct:a1', 'skatteverket'])).toBe(
+      'acct:a1',
+    )
+    expect(resolveEffectiveSourceFilter('skatteverket', ['all', 'skatteverket'])).toBe(
+      'skatteverket',
+    )
+  })
+
+  it('falls back to all when the wanted id is missing (items still loading or source stale)', () => {
+    expect(resolveEffectiveSourceFilter('acct:a1', ['all'])).toBe('all')
+    expect(resolveEffectiveSourceFilter('skatteverket', ['all', 'acct:a1'])).toBe('all')
+    expect(resolveEffectiveSourceFilter('bank:other', ['all', 'acct:a1'])).toBe('all')
+  })
+
+  it('passes all through regardless of items', () => {
+    expect(resolveEffectiveSourceFilter('all', [])).toBe('all')
+    expect(resolveEffectiveSourceFilter('all', ['all', 'acct:a1'])).toBe('all')
+  })
+})
+
+describe('readStoredSourceFilter / writeStoredSourceFilter', () => {
+  it('round-trips a filter under the per-company key', () => {
+    stubLocalStorage()
+    writeStoredSourceFilter('company-a', 'acct:a1')
+    expect(readStoredSourceFilter('company-a')).toBe('acct:a1')
+  })
+
+  it('keeps companies separate: one company never reads another company value', () => {
+    stubLocalStorage()
+    writeStoredSourceFilter('company-a', 'acct:a1')
+    writeStoredSourceFilter('company-b', 'skatteverket')
+    expect(readStoredSourceFilter('company-a')).toBe('acct:a1')
+    expect(readStoredSourceFilter('company-b')).toBe('skatteverket')
+    expect(readStoredSourceFilter('company-c')).toBe('all')
+  })
+
+  it('returns all when the stored value is invalid', () => {
+    stubLocalStorage({ [SOURCE_FILTER_STORAGE_PREFIX + 'company-a']: 'garbage' })
+    expect(readStoredSourceFilter('company-a')).toBe('all')
+  })
+
+  it('returns all when localStorage throws', () => {
+    vi.stubGlobal('window', {
+      localStorage: {
+        getItem: () => {
+          throw new Error('denied')
+        },
+        setItem: () => {
+          throw new Error('denied')
+        },
+        removeItem: () => {
+          throw new Error('denied')
+        },
+      },
+    })
+    expect(readStoredSourceFilter('company-a')).toBe('all')
+    // Write must swallow the failure too.
+    expect(() => writeStoredSourceFilter('company-a', 'bank')).not.toThrow()
+  })
+
+  it('returns all when window is unavailable (SSR/node)', () => {
+    // No stub: vitest runs in the node environment, so window is undefined.
+    expect(readStoredSourceFilter('company-a')).toBe('all')
+    expect(() => writeStoredSourceFilter('company-a', 'bank')).not.toThrow()
+  })
+
+  it('removes the retired browser-wide v1 key on read and ignores its value', () => {
+    const store = stubLocalStorage({ [LEGACY_KEY]: 'skatteverket' })
+    expect(readStoredSourceFilter('company-a')).toBe('all')
+    expect(store.has(LEGACY_KEY)).toBe(false)
+  })
+})

components/transactions/source-filter-storage.ts

@@ -0,0 +1,58 @@
+import type { SourceFilter } from '@/components/transactions/transaction-types'
+
+// Per-company key (v2). The v1 key was browser-wide, so an acct:<id> picked
+// under one company leaked into every other company in the same browser;
+// v2 scopes the memory per company like the FyPicker/JournalEntryList idiom.
+export const SOURCE_FILTER_STORAGE_PREFIX = 'Accounted:transaction-source-filter:v2:'
+
+// The retired browser-wide key from #1105. Removed once on read so it does
+// not linger in users' storage forever.
+const LEGACY_SOURCE_FILTER_STORAGE_KEY = 'Accounted:transaction-source-filter:v1'
+
+// Validates a persisted or URL-provided value. Stale acct:<id> entries
+// (account removed or disabled) are handled by resolveEffectiveSourceFilter,
+// which falls back to 'all' whenever the id is not among the picker items.
+export function isSourceFilter(value: string | null): value is SourceFilter {
+  return (
+    value === 'all' ||
+    value === 'bank' ||
+    value === 'bank:other' ||
+    value === 'skatteverket' ||
+    (value?.startsWith('acct:') ?? false)
+  )
+}
+
+export function readStoredSourceFilter(companyId: string): SourceFilter {
+  try {
+    // One-time cleanup of the legacy browser-wide key; v2 ignores its value.
+    window.localStorage.removeItem(LEGACY_SOURCE_FILTER_STORAGE_KEY)
+    const stored = window.localStorage.getItem(SOURCE_FILTER_STORAGE_PREFIX + companyId)
+    if (isSourceFilter(stored)) return stored
+  } catch {
+    // localStorage may be unavailable. Fall through to the default.
+  }
+  return 'all'
+}
+
+export function writeStoredSourceFilter(companyId: string, next: SourceFilter): void {
+  try {
+    window.localStorage.setItem(SOURCE_FILTER_STORAGE_PREFIX + companyId, next)
+  } catch {
+    // localStorage may be unavailable. The in-memory filter still works.
+  }
+}
+
+// The wanted filter (persisted choice or URL override) applies only while its
+// source actually exists among the picker items. While async sources
+// (cash accounts, skv rows, transactions) are still loading, or when a source
+// went stale (account disabled, skattekonto drained), the page shows 'all';
+// the wanted value stays intact so the choice springs back when the source
+// reappears. This derivation replaces the old reset-guard effect, which raced
+// the loads and permanently reset the in-memory filter on every mount.
+export function resolveEffectiveSourceFilter(
+  wanted: SourceFilter,
+  itemIds: readonly string[],
+): SourceFilter {
+  if (wanted === 'all') return 'all'
+  return itemIds.includes(wanted) ? wanted : 'all'
+}