feat: implement fiscal period date fields component and validation logic (#301)

* feat: implement fiscal period date fields component and validation logic

* feat: update fiscal period validation and naming logic

lib/bookkeeping/__tests__/validate-period-duration.test.ts

@@ -64,12 +64,12 @@ describe('validatePeriodDuration', () => {
     expect(validatePeriodDuration('2025-03-25', '2025-12-31', { isFirstPeriod: true })).toBeNull()
   })
 
-  it('allows mid-month start for first period (October)', () => {
-    expect(validatePeriodDuration('2025-10-15', '2025-12-31', { isFirstPeriod: true })).toBeNull()
+  it('allows mid-month start for first period (July)', () => {
+    expect(validatePeriodDuration('2025-07-15', '2025-12-31', { isFirstPeriod: true })).toBeNull()
   })
 
-  it('still allows day-1 start for first period', () => {
-    expect(validatePeriodDuration('2025-10-01', '2025-12-31', { isFirstPeriod: true })).toBeNull()
+  it('still allows day-1 start for first period (6 months)', () => {
+    expect(validatePeriodDuration('2025-07-01', '2025-12-31', { isFirstPeriod: true })).toBeNull()
   })
 
   it('enforces end-of-month even for first period', () => {
@@ -84,6 +84,26 @@ describe('validatePeriodDuration', () => {
     expect(result).toContain('18 months')
   })
 
+  it('enforces 6-month minimum for first period (2 months)', () => {
+    expect(validatePeriodDuration('2026-03-25', '2026-05-31', { isFirstPeriod: true })).toBe(
+      'First fiscal period must be at least 6 months (BFL 3 kap.)'
+    )
+  })
+
+  it('enforces 6-month minimum for first period (5 months)', () => {
+    expect(validatePeriodDuration('2026-08-01', '2026-12-31', { isFirstPeriod: true })).toBe(
+      'First fiscal period must be at least 6 months (BFL 3 kap.)'
+    )
+  })
+
+  it('allows exactly 6 months for first period', () => {
+    expect(validatePeriodDuration('2026-07-01', '2026-12-31', { isFirstPeriod: true })).toBeNull()
+  })
+
+  it('realistic customer case: 2026-03-25 to 2027-02-28', () => {
+    expect(validatePeriodDuration('2026-03-25', '2027-02-28', { isFirstPeriod: true })).toBeNull()
+  })
+
   it('returns error when end is not last day of month', () => {
     expect(validatePeriodDuration('2025-01-01', '2025-12-15')).toBe(
       'Period end must be the last day of a month'

lib/bookkeeping/validate-period-duration.ts

@@ -62,5 +62,10 @@ export function validatePeriodDuration(start: string, end: string, options?: Val
     return `Period duration ${months} months exceeds maximum 18 months (BFL 3 kap.)`
   }
 
+  // First fiscal period must be at least 6 months per BFL 3 kap.
+  if (options?.isFirstPeriod && months < 6) {
+    return `First fiscal period must be at least 6 months (BFL 3 kap.)`
+  }
+
   return null
 }

lib/import/__tests__/sie-import.test.ts

@@ -6,6 +6,7 @@ import {
   ensureFiscalPeriod,
   importVouchers,
   computeVoucherNumberRanges,
+  linkOpeningBalanceEntryToPeriod,
 } from '../sie-import'
 import { createQueuedMockSupabase } from '@/tests/helpers'
 import type { ParsedSIEFile, AccountMapping } from '../types'
@@ -421,6 +422,84 @@ describe('ensureFiscalPeriod validation', () => {
   })
 })
 
+describe('linkOpeningBalanceEntryToPeriod', () => {
+  // Regression: SIE import created the opening-balance entry but never wrote
+  // its ID back to fiscal_periods. Without the link, getOpeningBalances falls
+  // through to summing all prior journal lines, which inflates balance-sheet
+  // accounts across multi-year imports (each year's IB double-counted against
+  // the prior year's UB).
+  type Supabase = Parameters<typeof linkOpeningBalanceEntryToPeriod>[0]
+
+  it('writes opening_balance_entry_id and opening_balances_set to the fiscal period', async () => {
+    const updates: Array<{ payload: Record<string, unknown>; filters: Record<string, unknown> }> = []
+
+    const supabase = {
+      from: (table: string) => {
+        if (table !== 'fiscal_periods') {
+          throw new Error(`Unexpected table: ${table}`)
+        }
+        let pendingPayload: Record<string, unknown> = {}
+        const filters: Record<string, unknown> = {}
+        const chain = {
+          update: (payload: Record<string, unknown>) => {
+            pendingPayload = payload
+            return chain
+          },
+          eq: (col: string, val: unknown) => {
+            filters[col] = val
+            return chain
+          },
+          then: (resolve: (v: unknown) => void) => {
+            updates.push({ payload: pendingPayload, filters: { ...filters } })
+            resolve({ data: null, error: null })
+          },
+        }
+        return chain
+      },
+    }
+
+    await linkOpeningBalanceEntryToPeriod(
+      supabase as unknown as Supabase,
+      'company-1',
+      'period-1',
+      'ob-entry-1',
+    )
+
+    expect(updates).toHaveLength(1)
+    expect(updates[0].payload).toEqual({
+      opening_balance_entry_id: 'ob-entry-1',
+      opening_balances_set: true,
+    })
+    expect(updates[0].filters).toEqual({
+      id: 'period-1',
+      company_id: 'company-1',
+    })
+  })
+
+  it('throws a descriptive error when the update fails', async () => {
+    const supabase = {
+      from: () => {
+        const chain = {
+          update: () => chain,
+          eq: () => chain,
+          then: (resolve: (v: unknown) => void) =>
+            resolve({ data: null, error: { message: 'permission denied' } }),
+        }
+        return chain
+      },
+    }
+
+    await expect(
+      linkOpeningBalanceEntryToPeriod(
+        supabase as unknown as Supabase,
+        'company-1',
+        'period-1',
+        'ob-entry-1',
+      ),
+    ).rejects.toThrow(/Failed to link opening balance entry.*permission denied/)
+  })
+})
+
 describe('isBalanceSheetAccount', () => {
   it('returns true for class 1 (assets)', () => {
     expect(isBalanceSheetAccount('1510')).toBe(true)

lib/import/sie-import.ts

@@ -207,6 +207,7 @@ async function cleanupStaleImportRecords(
     .eq('company_id', companyId)
     .eq('file_hash', fileHash)
     .in('status', ['pending', 'failed'])
+    .lt('created_at', oneHourAgo)
 }
 
 /**
@@ -458,6 +459,36 @@ async function createOpeningBalanceEntry(
   return entry.id
 }
 
+/**
+ * Link an opening-balance journal entry to its fiscal period so balance-sheet
+ * reports use the explicit IB path in getOpeningBalances() (reads only that
+ * entry's lines for IB) instead of falling through to summing all prior
+ * journal lines — which inflates multi-year imports, because each year's IB
+ * is double-counted against the prior year's UB.
+ *
+ * Mirrors the pattern used by the Excel-based OB import at
+ * app/api/import/opening-balance/execute/route.ts:224-231.
+ */
+export async function linkOpeningBalanceEntryToPeriod(
+  supabase: SupabaseClient,
+  companyId: string,
+  fiscalPeriodId: string,
+  openingBalanceEntryId: string
+): Promise<void> {
+  const { error } = await supabase
+    .from('fiscal_periods')
+    .update({
+      opening_balance_entry_id: openingBalanceEntryId,
+      opening_balances_set: true,
+    })
+    .eq('id', fiscalPeriodId)
+    .eq('company_id', companyId)
+
+  if (error) {
+    throw new Error(`Failed to link opening balance entry to fiscal period: ${error.message}`)
+  }
+}
+
 /**
  * Create journal entries from vouchers using batch insert for performance.
  *
@@ -1636,6 +1667,13 @@ export async function executeSIEImport(
           if (result.openingBalanceEntryId) {
             result.journalEntriesCreated++
             result.journalEntryIds.push(result.openingBalanceEntryId)
+
+            await linkOpeningBalanceEntryToPeriod(
+              supabase,
+              companyId,
+              result.fiscalPeriodId,
+              result.openingBalanceEntryId
+            )
           }
         }
       }