fix(transactions): resolve bank account from cash_account_id in bulk-book and direct-book dialogs (#770)

Follow-up to #769: applies the same fetch-on-open + resolveAccount pattern to
BulkBookDialog (manual tab bank-leg pre-fill) and BookDirectlyDialog (settlement
line in buildPrefillLines). Both dialogs now fetch /api/cash-accounts when they
open, gate the pre-fill on the fetch resolving, and resolve the correct BAS
ledger account per transaction instead of always emitting '1930'.

Adds lib/cash-accounts/resolve-account.ts (cherry of the utility from #769)
since that PR is not yet merged into main.

Signed-off-by: Jonas Flodén <jonas@floden.nu>

components/extensions/general/BookDirectlyDialog.tsx

@@ -28,7 +28,8 @@ import {
 import { getErrorMessage } from '@/lib/errors/get-error-message'
 import { formatVoucher } from '@/lib/bookkeeping/voucher-series-resolver'
 import { resolveSekAmount } from '@/lib/bookkeeping/currency-utils'
-import type { BASAccount, FiscalPeriod, InvoiceExtractionResult } from '@/types'
+import { resolveAccount } from '@/lib/cash-accounts/resolve-account'
+import type { BASAccount, CashAccount, FiscalPeriod, InvoiceExtractionResult } from '@/types'
 
 interface InboxItem {
   id: string
@@ -77,9 +78,12 @@ interface Props {
 // a transaction is selected and the document is in a foreign currency, the
 // transaction's SEK amount is the canonical figure. The cost-account row
 // stays blank — the user must pick a cost account themselves.
+// bankAccount defaults to '1930' but is replaced by the resolved ledger account
+// once the cash-accounts fetch completes.
 function buildPrefillLines(
   item: InboxItem,
-  selectedTransactionAmount: number | null = null
+  selectedTransactionAmount: number | null = null,
+  bankAccount: string = '1930',
 ): FormLine[] {
   const docTotal = item.extracted_data?.totals?.total ?? null
   const docVat = item.extracted_data?.totals?.vatAmount ?? null
@@ -125,7 +129,7 @@ function buildPrefillLines(
     })
   }
   lines.push({
-    account_number: '1930',
+    account_number: bankAccount,
     debit_amount: '',
     credit_amount: String(totalRounded),
   })
@@ -157,6 +161,9 @@ export default function BookDirectlyDialog({ open, onOpenChange, item, onSuccess
   // pending, or unsupported.
   const [fxRate, setFxRate] = useState<number | null>(null)
 
+  // null = fetch pending; array = loaded (may be empty on error — falls back to '1930')
+  const [cashAccounts, setCashAccounts] = useState<CashAccount[] | null>(null)
+
   const [periods, setPeriods] = useState<FiscalPeriod[]>([])
   const [accounts, setAccounts] = useState<BASAccount[]>([])
   const [entryDate, setEntryDate] = useState<string>(
@@ -169,6 +176,9 @@ export default function BookDirectlyDialog({ open, onOpenChange, item, onSuccess
     return [supplier, invoiceNum].filter(Boolean).join(' · ') || 'Bokföring från inkorg'
   })
   const [notes, setNotes] = useState<string>('')
+  // Start with blank lines; they are replaced once cashAccounts resolves (see
+  // the combined prefill effect below). This mirrors the TransactionBookingDialog
+  // pattern of gating JournalEntryForm on bankAccount !== null.
   const [lines, setLines] = useState<FormLine[]>(() => buildPrefillLines(item))
 
   // Transaction picker — optional selection.
@@ -181,11 +191,14 @@ export default function BookDirectlyDialog({ open, onOpenChange, item, onSuccess
 
   const [isSubmitting, setIsSubmitting] = useState(false)
 
-  // Reset state when a different item opens the dialog
+  // Reset state when a different item opens the dialog. We pass bankAccount
+  // here but it may still be null (fetch in flight) — in that case '1930' is
+  // used as a placeholder and the prefill-update effect below will overwrite
+  // the settlement line once the fetch resolves.
   useEffect(() => {
     if (!open) return
     setEntryDate(item.extracted_data?.invoice?.invoiceDate || new Date().toISOString().slice(0, 10))
-    setLines(buildPrefillLines(item))
+    setLines(buildPrefillLines(item, null, bankAccount ?? '1930'))
     setSelectedTransactionId(item.matched_transaction_id)
     const supplier = item.extracted_data?.supplier?.name?.trim() || ''
     const invoiceNum = item.extracted_data?.invoice?.invoiceNumber?.trim() || ''
@@ -218,6 +231,29 @@ export default function BookDirectlyDialog({ open, onOpenChange, item, onSuccess
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [open, targetCurrency, item.id])
 
+  // Fetch cash accounts once when the dialog opens so the settlement line can
+  // be routed to the correct ledger account instead of the hardcoded '1930'.
+  useEffect(() => {
+    if (!open) return
+    setCashAccounts(null)
+    let cancelled = false
+    fetch('/api/cash-accounts')
+      .then((r) => {
+        if (!r.ok) throw new Error(`cash-accounts fetch failed: ${r.status}`)
+        return r.json()
+      })
+      .then((json) => {
+        if (cancelled) return
+        setCashAccounts((json.data ?? []) as CashAccount[])
+      })
+      .catch(() => {
+        // Fall back to empty list — resolveAccount will return '1930'
+        if (!cancelled) setCashAccounts([])
+      })
+    return () => { cancelled = true }
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [open, item.id])
+
   // SEK-equivalent of the underlag total — the anchor for ranking candidates.
   const targetSek = useMemo(() => {
     if (targetAmount == null) return null
@@ -240,14 +276,37 @@ export default function BookDirectlyDialog({ open, onOpenChange, item, onSuccess
       : resolveSekAmount(tx.amount, tx.amount_sek ?? null, tx.currency, tx.exchange_rate ?? null)
   }, [selectedTransactionId, transactions])
 
+  // The settlement currency to resolve against:
+  // - When a transaction is selected, use that transaction's currency.
+  // - Otherwise, use the document's currency (falls back to SEK).
+  const settlementCurrency = useMemo(() => {
+    if (selectedTransactionId) {
+      const tx = transactions.find((t) => t.id === selectedTransactionId)
+      if (tx) return (tx.currency ?? 'SEK').toUpperCase()
+    }
+    return targetCurrency
+  }, [selectedTransactionId, transactions, targetCurrency])
+
+  // Resolved bank account — null while the cash-accounts fetch is in flight.
+  // Derived from the cash accounts list; falls back to '1930' if the list is
+  // empty or no single-currency match exists.
+  const bankAccount = useMemo<string | null>(() => {
+    if (cashAccounts === null) return null
+    const { account } = resolveAccount(cashAccounts, null, settlementCurrency)
+    return account
+  }, [cashAccounts, settlementCurrency])
+
   useEffect(() => {
     if (!open) return
-    // Update amounts when the transaction selection changes, but preserve
-    // user-entered account numbers. This handles "user typed cost account,
-    // then picked an SEK-denominated transaction" — we want the SEK figure
-    // to flow into the line amounts without forgetting their account pick.
+    // Update amounts when the transaction selection or resolved bank account
+    // changes, but preserve user-entered account numbers. This handles "user
+    // typed cost account, then picked an SEK-denominated transaction" — we
+    // want the SEK figure to flow into the line amounts without forgetting
+    // their account pick. bankAccount may be null while the fetch is in flight;
+    // pass '1930' as a safe placeholder in that case — the effect re-runs once
+    // the fetch resolves and bankAccount becomes non-null.
     setLines((current) => {
-      const next = buildPrefillLines(item, selectedTransactionAmount)
+      const next = buildPrefillLines(item, selectedTransactionAmount, bankAccount ?? '1930')
       return next.map((nl, i) => {
         const existing = current[i]
         if (!existing) return nl
@@ -257,7 +316,7 @@ export default function BookDirectlyDialog({ open, onOpenChange, item, onSuccess
         }
       })
     })
-  }, [open, item, selectedTransactionAmount])
+  }, [open, item, selectedTransactionAmount, bankAccount])
 
   // Fetch fiscal periods and accounts on first open
   useEffect(() => {

components/transactions/BulkBookDialog.tsx

@@ -4,6 +4,8 @@ import { useEffect, useMemo, useState } from 'react'
 import { useTranslations } from 'next-intl'
 import { createClient } from '@/lib/supabase/client'
 import { useCompany } from '@/contexts/CompanyContext'
+import { resolveAccount } from '@/lib/cash-accounts/resolve-account'
+import type { CashAccount } from '@/types'
 import {
   Dialog,
   DialogContent,
@@ -81,6 +83,8 @@ export default function BulkBookDialog({
   const [templates, setTemplates] = useState<BookingTemplateLibrary[]>([])
   const [loadingTemplates, setLoadingTemplates] = useState(true)
   const [selectedTemplateId, setSelectedTemplateId] = useState<string | null>(null)
+  // null = fetch pending; array = loaded (may be empty on error — falls back to '1930')
+  const [cashAccounts, setCashAccounts] = useState<CashAccount[] | null>(null)
   const [mode, setMode] = useState<Mode>('one_line_per_tx')
   const [description, setDescription] = useState('')
   const [manualLines, setManualLines] = useState<ManualLine[]>([])
@@ -137,6 +141,28 @@ export default function BulkBookDialog({
     }
   }, [open, company, supabase])
 
+  // Fetch cash accounts once when the dialog opens so the manual bank-leg
+  // pre-fill can resolve the correct ledger account per transaction.
+  useEffect(() => {
+    if (!open) return
+    setCashAccounts(null)
+    let cancelled = false
+    fetch('/api/cash-accounts')
+      .then((r) => {
+        if (!r.ok) throw new Error(`cash-accounts fetch failed: ${r.status}`)
+        return r.json()
+      })
+      .then((json) => {
+        if (cancelled) return
+        setCashAccounts((json.data ?? []) as CashAccount[])
+      })
+      .catch(() => {
+        // Fall back to empty list — resolveAccount will return '1930'
+        if (!cancelled) setCashAccounts([])
+      })
+    return () => { cancelled = true }
+  }, [open])
+
   // Reset state when dialog closes so the next open starts clean.
   useEffect(() => {
     if (!open) {
@@ -145,31 +171,43 @@ export default function BulkBookDialog({
       setMode('one_line_per_tx')
       setDescription('')
       setManualLines([])
+      setCashAccounts(null)
     } else if (sharedDate) {
       // Pre-fill description with a sensible default the user can edit.
       setDescription(t('default_description', { date: sharedDate }))
     }
   }, [open, sharedDate, t])
 
-  // Pre-fill the bank side from the txs (one line per tx on 1930 with
-  // the correct Dr/Cr direction). We intentionally do NOT pre-fill a
-  // counterpart account: swedish-compliance flagged that a hardcoded
-  // 3001/5800 prefill nudges users into submitting verifikat without a
-  // VAT line (26xx) for momsregistrerade affärshändelser. The bank
-  // side is the unambiguous part the user always wants; the
+  // Pre-fill the bank side from the txs (one line per tx with the resolved
+  // ledger account and correct Dr/Cr direction). We intentionally do NOT
+  // pre-fill a counterpart account: swedish-compliance flagged that a
+  // hardcoded 3001/5800 prefill nudges users into submitting verifikat
+  // without a VAT line (26xx) for momsregistrerade affärshändelser. The
+  // bank side is the unambiguous part the user always wants; the
   // counterpart (and any VAT split) is the user's responsibility.
+  // Gate on cashAccounts !== null so lines are only built after the account
+  // fetch resolves — this prevents the form from briefly showing '1930' when
+  // the resolved account differs.
   useEffect(() => {
     if (tab !== 'manual') return
     if (manualLines.length > 0) return
     if (transactions.length === 0) return
+    if (cashAccounts === null) return
     const isIncome = direction === 'income'
-    const bankLines: ManualLine[] = transactions.map((tx) => ({
-      id: newManualLineId(),
-      account_number: '1930',
-      debit_amount: isIncome ? Math.abs(tx.amount).toFixed(2).replace('.', ',') : '',
-      credit_amount: isIncome ? '' : Math.abs(tx.amount).toFixed(2).replace('.', ','),
-      line_description: (tx.description || '').slice(0, 40).trim(),
-    }))
+    const bankLines: ManualLine[] = transactions.map((tx) => {
+      const { account } = resolveAccount(
+        cashAccounts,
+        tx.cash_account_id ?? null,
+        tx.currency ?? 'SEK',
+      )
+      return {
+        id: newManualLineId(),
+        account_number: account,
+        debit_amount: isIncome ? Math.abs(tx.amount).toFixed(2).replace('.', ',') : '',
+        credit_amount: isIncome ? '' : Math.abs(tx.amount).toFixed(2).replace('.', ','),
+        line_description: (tx.description || '').slice(0, 40).trim(),
+      }
+    })
     // One empty counterpart row to scaffold the next entry. Account
     // left blank — user must choose, which avoids the no-VAT trap.
     const counterpart: ManualLine = {
@@ -180,7 +218,7 @@ export default function BulkBookDialog({
       line_description: '',
     }
     setManualLines([...bankLines, counterpart])
-  }, [tab, manualLines.length, transactions, direction])
+  }, [tab, manualLines.length, transactions, direction, cashAccounts])
 
   // Live line preview — driven by either the template/mode pair (template
   // tab) or the user-edited manual lines (manual tab). Same downstream

lib/cash-accounts/resolve-account.ts

@@ -0,0 +1,31 @@
+import type { CashAccount } from '@/types'
+
+export interface ResolvedAccount {
+  account: string
+  fallback: boolean
+}
+
+/**
+ * Resolve the BAS ledger account number for a bank transaction.
+ *
+ * Resolution order:
+ * 1. cash_account_id is set → return that cash account's ledger_account.
+ * 2. Exactly one enabled account for the transaction currency → return it.
+ * 3. Give up → return '1930' with fallback=true.
+ */
+export function resolveAccount(
+  cashAccounts: CashAccount[],
+  cashAccountId: string | null,
+  currency: string,
+): ResolvedAccount {
+  if (cashAccountId) {
+    const bound = cashAccounts.find((a) => a.id === cashAccountId)
+    // If an explicit ID was given but not found, skip the currency fallback and
+    // return 1930 with fallback=true — the missing link is a data integrity signal.
+    if (bound) return { account: bound.ledger_account, fallback: false }
+    return { account: '1930', fallback: true }
+  }
+  const sameCurrency = cashAccounts.filter((a) => a.enabled && a.currency === currency)
+  if (sameCurrency.length === 1) return { account: sameCurrency[0].ledger_account, fallback: false }
+  return { account: '1930', fallback: true }
+}