import type { SupabaseClient } from '@supabase/supabase-js'
import { fetchAllRows } from '@/lib/supabase/fetch-all'
import type {
  FiscalPeriod,
  JournalEntry,
  JournalEntryLine,
} from '@/types'
import type {
  INK2Declaration,
  INK2RRutor,
  INK2Rutor,
  INK2SRutor,
  INK2AccountMapping,
  INK2RSRUCode,
} from './types'
import {
  INK2R_ASSET_CODES,
  INK2R_EQUITY_LIABILITY_CODES,
} from './types'

/**
 * INK2 Declaration Engine
 *
 * Generates INK2 (huvudblankett), INK2R (räkenskapsschema), and INK2S
 * (skattemässiga justeringar) for aktiebolag tax reporting.
 *
 * Account mappings follow the official BAS-to-SRU mapping from
 * bas.se/kontoplaner/sru/ and Skatteverket field code spec.
 *
 * INK2R contains the full balance sheet + income statement.
 * INK2S auto-derives basic fields (result + tax → taxable result), as well as
 * periodiseringsfond and överavskrivningar when those have been posted via the
 * bokslut-dispositions calculators in lib/bokslut/.
 */

/**
 * BAS-to-SRU account mappings for INK2R
 * Source: bas.se/kontoplaner/sru/ (stable since 2017)
 */
export const INK2R_ACCOUNT_MAPPINGS: INK2AccountMapping[] = [
  // ---- Balance sheet: Assets ----
  {
    sruCode: '7201',
    description: 'Koncessioner, patent, licenser, varumärken, goodwill',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [
      { start: '1010', end: '1079' },
      { start: '1090', end: '1099' },
    ],
  },
  {
    sruCode: '7202',
    description: 'Förskott immateriella anläggningstillgångar',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [{ start: '1080', end: '1089' }],
  },
  {
    sruCode: '7214',
    description: 'Byggnader och mark',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [
      { start: '1100', end: '1119' },
      { start: '1130', end: '1179' },
      { start: '1190', end: '1199' },
    ],
  },
  {
    sruCode: '7215',
    description: 'Maskiner, inventarier, övriga materiella',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [{ start: '1200', end: '1299' }],
  },
  {
    sruCode: '7216',
    description: 'Förbättringsutgifter på annans fastighet',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [{ start: '1120', end: '1129' }],
  },
  {
    sruCode: '7217',
    description: 'Pågående nyanläggningar, förskott materiella',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [{ start: '1180', end: '1189' }],
  },
  {
    sruCode: '7230',
    description: 'Andelar i koncernföretag',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [{ start: '1311', end: '1316' }],
  },
  {
    sruCode: '7231',
    description: 'Andelar i intresseföretag',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [{ start: '1330', end: '1338' }],
  },
  {
    sruCode: '7233',
    description: 'Ägarintressen övriga företag + långfristiga värdepapper',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [
      { start: '1350', end: '1359' },
      { start: '1380', end: '1389' },
    ],
  },
  {
    sruCode: '7232',
    description: 'Fordringar koncern/intresse',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [
      { start: '1320', end: '1329' },
      { start: '1340', end: '1349' },
    ],
  },
  {
    sruCode: '7234',
    description: 'Lån till delägare eller närstående',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [{ start: '1360', end: '1369' }],
  },
  {
    sruCode: '7235',
    description: 'Övriga långfristiga fordringar',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [
      { start: '1370', end: '1379' },
      { start: '1390', end: '1399' },
    ],
  },
  {
    sruCode: '7241',
    description: 'Råvaror och förnödenheter',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [{ start: '1410', end: '1419' }],
  },
  {
    sruCode: '7242',
    description: 'Varor under tillverkning',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [{ start: '1440', end: '1449' }],
  },
  {
    sruCode: '7243',
    description: 'Färdiga varor och handelsvaror',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [{ start: '1450', end: '1469' }],
  },
  {
    sruCode: '7244',
    description: 'Övriga lagertillgångar',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [{ start: '1470', end: '1489' }],
  },
  {
    sruCode: '7245',
    description: 'Pågående arbeten för annans räkning',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [{ start: '1490', end: '1499' }],
  },
  {
    sruCode: '7246',
    description: 'Förskott till leverantörer',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [{ start: '1400', end: '1409' }],
  },
  {
    sruCode: '7251',
    description: 'Kundfordringar',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [{ start: '1500', end: '1519' }],
  },
  {
    sruCode: '7252',
    description: 'Fordringar koncern/intresse (kortfristiga)',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [{ start: '1560', end: '1579' }],
  },
  {
    sruCode: '7261',
    description: 'Övriga fordringar',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [
      { start: '1520', end: '1559' },
      { start: '1580', end: '1599' },
      { start: '1600', end: '1619' },
      { start: '1621', end: '1699' },
    ],
  },
  {
    sruCode: '7262',
    description: 'Upparbetad men ej fakturerad intäkt',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [{ start: '1620', end: '1620' }],
  },
  {
    sruCode: '7263',
    description: 'Förutbetalda kostnader och upplupna intäkter',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [{ start: '1700', end: '1799' }],
  },
  {
    sruCode: '7270',
    description: 'Andelar i koncernföretag (kortfristiga)',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [{ start: '1860', end: '1869' }],
  },
  {
    sruCode: '7271',
    description: 'Övriga kortfristiga placeringar',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [
      { start: '1800', end: '1859' },
      { start: '1870', end: '1899' },
    ],
  },
  {
    sruCode: '7281',
    description: 'Kassa, bank och redovisningsmedel',
    section: 'assets',
    normalBalance: 'debit',
    accountRanges: [{ start: '1900', end: '1999' }],
  },

  // ---- Balance sheet: Equity & Liabilities ----
  {
    sruCode: '7301',
    description: 'Bundet eget kapital',
    section: 'equity_liabilities',
    normalBalance: 'credit',
    accountRanges: [{ start: '2010', end: '2089' }],
  },
  {
    sruCode: '7302',
    description: 'Fritt eget kapital',
    section: 'equity_liabilities',
    normalBalance: 'credit',
    accountRanges: [{ start: '2090', end: '2099' }],
  },
  {
    sruCode: '7321',
    description: 'Periodiseringsfonder',
    section: 'equity_liabilities',
    normalBalance: 'credit',
    accountRanges: [
      { start: '2100', end: '2109' },
      { start: '2110', end: '2129' },
    ],
  },
  {
    sruCode: '7322',
    description: 'Ackumulerade överavskrivningar',
    section: 'equity_liabilities',
    normalBalance: 'credit',
    accountRanges: [{ start: '2150', end: '2159' }],
  },
  {
    sruCode: '7323',
    description: 'Övriga obeskattade reserver',
    section: 'equity_liabilities',
    normalBalance: 'credit',
    accountRanges: [
      { start: '2130', end: '2149' },
      { start: '2160', end: '2199' },
    ],
  },
  {
    sruCode: '7331',
    description: 'Pensionsavsättningar tryggandelagen',
    section: 'equity_liabilities',
    normalBalance: 'credit',
    accountRanges: [{ start: '2210', end: '2219' }],
  },
  {
    sruCode: '7332',
    description: 'Övriga pensionsavsättningar',
    section: 'equity_liabilities',
    normalBalance: 'credit',
    accountRanges: [{ start: '2220', end: '2229' }],
  },
  {
    sruCode: '7333',
    description: 'Övriga avsättningar',
    section: 'equity_liabilities',
    normalBalance: 'credit',
    accountRanges: [{ start: '2230', end: '2299' }],
  },
  {
    sruCode: '7350',
    description: 'Obligationslån',
    section: 'equity_liabilities',
    normalBalance: 'credit',
    accountRanges: [
      { start: '2300', end: '2319' },
      { start: '2320', end: '2329' },
    ],
  },
  {
    sruCode: '7351',
    description: 'Checkräkningskredit (långfristig)',
    section: 'equity_liabilities',
    normalBalance: 'credit',
    accountRanges: [{ start: '2330', end: '2339' }],
  },
  {
    sruCode: '7352',
    description: 'Övriga skulder kreditinstitut (långfristiga)',
    section: 'equity_liabilities',
    normalBalance: 'credit',
    accountRanges: [{ start: '2340', end: '2359' }],
  },
  {
    sruCode: '7353',
    description: 'Skulder koncern/intresse (långfristiga)',
    section: 'equity_liabilities',
    normalBalance: 'credit',
    accountRanges: [{ start: '2360', end: '2379' }],
  },
  {
    sruCode: '7354',
    description: 'Övriga skulder (långfristiga)',
    section: 'equity_liabilities',
    normalBalance: 'credit',
    accountRanges: [{ start: '2380', end: '2399' }],
  },
  {
    sruCode: '7360',
    description: 'Checkräkningskredit (kortfristig)',
    section: 'equity_liabilities',
    normalBalance: 'credit',
    accountRanges: [{ start: '2410', end: '2419' }],
  },
  {
    sruCode: '7361',
    description: 'Övriga skulder kreditinstitut (kortfristiga)',
    section: 'equity_liabilities',
    normalBalance: 'credit',
    accountRanges: [{ start: '2420', end: '2439' }],
  },
  {
    sruCode: '7362',
    description: 'Förskott från kunder',
    section: 'equity_liabilities',
    normalBalance: 'credit',
    accountRanges: [{ start: '2400', end: '2409' }],
  },
  {
    sruCode: '7363',
    description: 'Pågående arbeten (skuldsida)',
    section: 'equity_liabilities',
    normalBalance: 'credit',
    accountRanges: [{ start: '2450', end: '2459' }],
  },
  {
    sruCode: '7364',
    description: 'Fakturerad men ej upparbetad intäkt',
    section: 'equity_liabilities',
    normalBalance: 'credit',
    accountRanges: [{ start: '2460', end: '2469' }],
  },
  {
    sruCode: '7365',
    description: 'Leverantörsskulder',
    section: 'equity_liabilities',
    normalBalance: 'credit',
    accountRanges: [{ start: '2440', end: '2449' }],
  },
  {
    sruCode: '7366',
    description: 'Växelskulder',
    section: 'equity_liabilities',
    normalBalance: 'credit',
    accountRanges: [{ start: '2490', end: '2490' }],
  },
  {
    sruCode: '7367',
    description: 'Skulder koncern/intresse (kortfristiga)',
    section: 'equity_liabilities',
    normalBalance: 'credit',
    accountRanges: [{ start: '2470', end: '2479' }],
  },
  {
    sruCode: '7369',
    description: 'Övriga skulder (kortfristiga)',
    section: 'equity_liabilities',
    normalBalance: 'credit',
    accountRanges: [
      { start: '2480', end: '2489' },
      { start: '2491', end: '2499' },
      { start: '2600', end: '2799' },
      { start: '2800', end: '2899' },
    ],
  },
  {
    sruCode: '7368',
    description: 'Skatteskulder',
    section: 'equity_liabilities',
    normalBalance: 'credit',
    accountRanges: [{ start: '2500', end: '2599' }],
  },
  {
    sruCode: '7370',
    description: 'Upplupna kostnader och förutbetalda intäkter',
    section: 'equity_liabilities',
    normalBalance: 'credit',
    accountRanges: [{ start: '2900', end: '2999' }],
  },

  // ---- Income statement ----
  {
    sruCode: '7410',
    description: 'Nettoomsättning',
    section: 'income_statement',
    normalBalance: 'credit',
    accountRanges: [{ start: '3000', end: '3799' }],
  },
  {
    sruCode: '7412',
    description: 'Aktiverat arbete för egen räkning',
    section: 'income_statement',
    normalBalance: 'credit',
    accountRanges: [{ start: '3800', end: '3899' }],
  },
  {
    sruCode: '7413',
    description: 'Övriga rörelseintäkter',
    section: 'income_statement',
    normalBalance: 'credit',
    accountRanges: [{ start: '3900', end: '3999' }],
  },
  {
    sruCode: '7411',
    description: 'Förändring av lager',
    section: 'income_statement',
    normalBalance: 'net',
    accountRanges: [{ start: '4900', end: '4999' }],
  },
  {
    sruCode: '7511',
    description: 'Råvaror och förnödenheter',
    section: 'income_statement',
    normalBalance: 'debit',
    accountRanges: [
      { start: '4000', end: '4499' },
      { start: '4500', end: '4599' },
      { start: '4700', end: '4899' },
    ],
  },
  {
    sruCode: '7512',
    description: 'Handelsvaror',
    section: 'income_statement',
    normalBalance: 'debit',
    accountRanges: [{ start: '4600', end: '4699' }],
  },
  // CRITICAL: BAS 5000-6999 ALL map to SRU 7513
  {
    sruCode: '7513',
    description: 'Övriga externa kostnader',
    section: 'income_statement',
    normalBalance: 'debit',
    accountRanges: [{ start: '5000', end: '6999' }],
  },
  {
    sruCode: '7514',
    description: 'Personalkostnader',
    section: 'income_statement',
    normalBalance: 'debit',
    accountRanges: [{ start: '7000', end: '7699' }],
  },
  {
    sruCode: '7515',
    description: 'Av- och nedskrivningar materiella/immateriella',
    section: 'income_statement',
    normalBalance: 'debit',
    accountRanges: [{ start: '7800', end: '7899' }],
  },
  {
    sruCode: '7516',
    description: 'Nedskrivningar omsättningstillgångar',
    section: 'income_statement',
    normalBalance: 'debit',
    accountRanges: [{ start: '7700', end: '7799' }],
  },
  {
    sruCode: '7517',
    description: 'Övriga rörelsekostnader',
    section: 'income_statement',
    normalBalance: 'debit',
    accountRanges: [{ start: '7900', end: '7999' }],
  },
  {
    sruCode: '7414',
    description: 'Resultat från andelar i koncernföretag',
    section: 'income_statement',
    normalBalance: 'net',
    accountRanges: [{ start: '8000', end: '8099' }],
  },
  {
    sruCode: '7415',
    description: 'Resultat från andelar i intresseföretag',
    section: 'income_statement',
    normalBalance: 'net',
    accountRanges: [{ start: '8100', end: '8199' }],
  },
  {
    sruCode: '7423',
    description: 'Resultat från övriga företag med ägarintresse',
    section: 'income_statement',
    normalBalance: 'net',
    accountRanges: [{ start: '8200', end: '8269' }],
  },
  {
    sruCode: '7416',
    description: 'Resultat från övriga finansiella anläggningstillgångar',
    section: 'income_statement',
    normalBalance: 'net',
    accountRanges: [{ start: '8270', end: '8299' }],
  },
  {
    sruCode: '7417',
    description: 'Övriga ränteintäkter och liknande',
    section: 'income_statement',
    normalBalance: 'credit',
    accountRanges: [{ start: '8300', end: '8399' }],
  },
  {
    sruCode: '7522',
    description: 'Räntekostnader och liknande',
    section: 'income_statement',
    normalBalance: 'debit',
    accountRanges: [{ start: '8400', end: '8499' }],
  },
  {
    sruCode: '7521',
    description: 'Nedskrivningar finansiella anläggningstillgångar',
    section: 'income_statement',
    normalBalance: 'debit',
    accountRanges: [{ start: '8500', end: '8599' }],
  },
  // Bokslutsdispositioner — account numbers per BAS 2020 (verified against
  // lib/bookkeeping/bas-data/class-8-financial.ts).
  {
    sruCode: '7525',
    description: 'Avsättning till periodiseringsfond',
    section: 'income_statement',
    normalBalance: 'debit',
    accountRanges: [{ start: '8811', end: '8811' }],
  },
  {
    sruCode: '7420',
    description: 'Återföring av periodiseringsfond',
    section: 'income_statement',
    normalBalance: 'credit',
    accountRanges: [{ start: '8819', end: '8819' }],
  },
  {
    sruCode: '7419',
    description: 'Mottagna koncernbidrag',
    section: 'income_statement',
    normalBalance: 'credit',
    accountRanges: [{ start: '8820', end: '8820' }],
  },
  {
    sruCode: '7524',
    description: 'Lämnade koncernbidrag',
    section: 'income_statement',
    normalBalance: 'debit',
    accountRanges: [{ start: '8830', end: '8830' }],
  },
  {
    sruCode: '7421',
    description: 'Förändring av överavskrivningar',
    section: 'income_statement',
    normalBalance: 'net',
    // 8850 = grupp, 8851-8853 = per kategori (immateriella, byggnader, M&I)
    accountRanges: [{ start: '8850', end: '8859' }],
  },
  {
    sruCode: '7422',
    description: 'Övriga bokslutsdispositioner',
    section: 'income_statement',
    normalBalance: 'net',
    // 8840 = Lämnade gottgörelser, 8860-8899 = övriga
    accountRanges: [
      { start: '8840', end: '8840' },
      { start: '8860', end: '8899' },
    ],
  },
  {
    sruCode: '7528',
    description: 'Skatt på årets resultat',
    section: 'income_statement',
    normalBalance: 'debit',
    accountRanges: [{ start: '8900', end: '8989' }],
  },
  // 7450/7550 (årets resultat vinst/förlust) are calculated, not mapped from accounts
]

/**
 * Check if an account number falls within a mapping's ranges
 */
export function isAccountInMapping(accountNumber: string, mapping: INK2AccountMapping): boolean {
  for (const range of mapping.accountRanges) {
    if (accountNumber >= range.start && accountNumber <= range.end) {
      if (range.exclude && range.exclude.includes(accountNumber)) {
        continue
      }
      return true
    }
  }
  return false
}

/**
 * Truncate to nearest krona (drop öre) per SFL 22 kap. 1 §
 */
function truncateToKrona(value: number): number {
  return value >= 0 ? Math.floor(value) : Math.ceil(value)
}

/**
 * Check if the balance sheet totals differ beyond the expected rounding tolerance.
 */
export function checkBalanceWarning(totalAssets: number, totalEquityLiabilities: number): string | null {
  const balanceDiff = Math.abs(totalAssets - totalEquityLiabilities)
  const ROUNDING_TOLERANCE_KR = 2
  if (balanceDiff > ROUNDING_TOLERANCE_KR && (totalAssets > 0 || totalEquityLiabilities > 0)) {
    return `Balansräkningen är inte i balans. Tillgångar: ${totalAssets} kr, Eget kapital och skulder: ${totalEquityLiabilities} kr (differens: ${balanceDiff} kr).`
  }
  return null
}

/** Create zero-initialized INK2R rutor */
function createEmptyINK2RRutor(): INK2RRutor {
  return {
    '7201': 0, '7202': 0, '7214': 0, '7215': 0, '7216': 0, '7217': 0,
    '7230': 0, '7231': 0, '7233': 0, '7232': 0, '7234': 0, '7235': 0,
    '7241': 0, '7242': 0, '7243': 0, '7244': 0, '7245': 0, '7246': 0,
    '7251': 0, '7252': 0, '7261': 0, '7262': 0, '7263': 0,
    '7270': 0, '7271': 0, '7281': 0,
    '7301': 0, '7302': 0,
    '7321': 0, '7322': 0, '7323': 0,
    '7331': 0, '7332': 0, '7333': 0,
    '7350': 0, '7351': 0, '7352': 0, '7353': 0, '7354': 0,
    '7360': 0, '7361': 0, '7362': 0, '7363': 0, '7364': 0,
    '7365': 0, '7366': 0, '7367': 0, '7369': 0, '7368': 0, '7370': 0,
    '7410': 0, '7411': 0, '7412': 0, '7413': 0,
    '7511': 0, '7512': 0, '7513': 0, '7514': 0, '7515': 0, '7516': 0, '7517': 0,
    '7414': 0, '7415': 0, '7423': 0, '7416': 0, '7417': 0,
    '7521': 0, '7522': 0,
    '7524': 0, '7419': 0, '7420': 0, '7525': 0, '7421': 0, '7422': 0,
    '7528': 0,
    '7450': 0, '7550': 0,
  }
}

// Reuse canonical code arrays from types.ts (single source of truth)
const ASSET_CODES = INK2R_ASSET_CODES
const EQUITY_LIABILITY_CODES = INK2R_EQUITY_LIABILITY_CODES

/**
 * Generate INK2 declaration for a fiscal period
 */
export async function generateINK2Declaration(
  supabase: SupabaseClient,
  companyId: string,
  fiscalPeriodId: string
): Promise<INK2Declaration> {

  // Fetch fiscal period
  const { data: period, error: periodError } = await supabase
    .from('fiscal_periods')
    .select('*')
    .eq('id', fiscalPeriodId)
    .eq('company_id', companyId)
    .single()

  if (periodError || !period) {
    throw new Error('Fiscal period not found')
  }

  // Fetch company settings
  const { data: settings } = await supabase
    .from('company_settings')
    .select('company_name, org_number, entity_type, address_line1, postal_code, city, email')
    .eq('company_id', companyId)
    .single()

  // Resolve entity_type: prefer company_settings, fall back to companies table (NOT NULL, always reliable)
  let entityType = settings?.entity_type
  if (!entityType) {
    const { data: company, error: companyError } = await supabase
      .from('companies')
      .select('entity_type')
      .eq('id', companyId)
      .single()
    if (companyError) throw new Error(`Failed to resolve entity type: ${companyError.message}`)
    entityType = company?.entity_type
  }

  if (entityType !== 'aktiebolag') {
    throw new Error('INK2 declaration is only for aktiebolag (limited company)')
  }

  // Fetch all posted journal entries with lines for this period
  const { data: entries, error: entriesError } = await supabase
    .from('journal_entries')
    .select('*, lines:journal_entry_lines(*)')
    .eq('company_id', companyId)
    .eq('fiscal_period_id', fiscalPeriodId)
    .in('status', ['posted', 'reversed'])

  if (entriesError) {
    throw new Error(`Failed to fetch journal entries: ${entriesError.message}`)
  }

  // Fetch chart of accounts for account names
  const accounts = await fetchAllRows<{ account_number: string; account_name: string }>(({ from, to }) =>
    supabase
      .from('chart_of_accounts')
      .select('account_number, account_name')
      .eq('company_id', companyId)
      .order('account_number', { ascending: true })
      .range(from, to)
  )

  const accountNameMap = new Map<string, string>()
  for (const acc of accounts) {
    accountNameMap.set(acc.account_number, acc.account_name)
  }

  // Calculate balances per account (debit - credit)
  const accountBalances = new Map<string, number>()

  for (const entry of (entries as JournalEntry[]) || []) {
    const lines = (entry.lines as JournalEntryLine[]) || []
    for (const line of lines) {
      const current = accountBalances.get(line.account_number) || 0
      const netAmount = (Number(line.debit_amount) || 0) - (Number(line.credit_amount) || 0)
      accountBalances.set(line.account_number, current + netAmount)
    }
  }

  // Initialize INK2R rutor and breakdown
  const ink2r = createEmptyINK2RRutor()
  const allCodes = Object.keys(ink2r) as INK2RSRUCode[]
  const breakdown = {} as INK2Declaration['breakdown']
  for (const code of allCodes) {
    breakdown[code] = { accounts: [], total: 0 }
  }

  const warnings: string[] = []

  // Process each account balance against INK2R mappings
  for (const [accountNumber, balance] of accountBalances) {
    if (Math.abs(balance) < 0.01) continue

    // Skip account 8999 — årets resultat is calculated
    if (accountNumber === '8999') continue

    let mapped = false
    for (const mapping of INK2R_ACCOUNT_MAPPINGS) {
      if (isAccountInMapping(accountNumber, mapping)) {
        let amount: number

        if (mapping.section === 'income_statement') {
          // Income statement sign convention per Skatteverket INK2R:
          // All amounts are reported as positive values on the form.
          // Revenue (credit normal): balance is negative in ledger, negate → positive
          // Cost (debit normal): balance is positive in ledger, keep → positive
          // Net: negate so positive = income, negative = cost
          if (mapping.normalBalance === 'credit') {
            amount = -balance
          } else if (mapping.normalBalance === 'debit') {
            // Costs: debit balance is positive in ledger, keep positive (Skatteverket convention)
            amount = balance
          } else {
            // Net: negate to match accounting convention
            amount = -balance
          }
        } else {
          // Balance sheet: all amounts reported as positive
          if (mapping.normalBalance === 'debit') {
            amount = balance
          } else {
            amount = -balance
          }
        }

        ink2r[mapping.sruCode] += amount

        breakdown[mapping.sruCode].accounts.push({
          accountNumber,
          accountName: accountNameMap.get(accountNumber) || `Konto ${accountNumber}`,
          amount: truncateToKrona(amount),
        })

        mapped = true
        break
      }
    }

    if (!mapped) {
      // BAS accounts 4500-4599, 4700-4899, and 1300-1310 have no standard SRU mapping
      // These are unusual and may indicate custom accounts
      const classChar = accountNumber.charAt(0)
      if (classChar >= '1' && classChar <= '8') {
        // Only warn for standard BAS range accounts that weren't mapped
        warnings.push(`Konto ${accountNumber} (${accountNameMap.get(accountNumber) || 'okänt'}) kunde inte mappas till ett SRU-fält.`)
      }
    }
  }

  // Truncate all INK2R rutor to whole kronor
  for (const code of allCodes) {
    ink2r[code] = truncateToKrona(ink2r[code])
    breakdown[code].total = ink2r[code]
  }

  // Calculate totals
  const totalAssets = ASSET_CODES.reduce((sum, code) => sum + ink2r[code], 0)
  const totalEquityLiabilities = EQUITY_LIABILITY_CODES.reduce((sum, code) => sum + ink2r[code], 0)

  // Operating result: revenue minus costs (costs are positive per Skatteverket convention)
  const operatingResult =
    ink2r['7410'] + ink2r['7411'] + ink2r['7412'] + ink2r['7413']
    - ink2r['7511'] - ink2r['7512'] - ink2r['7513'] - ink2r['7514']
    - ink2r['7515'] - ink2r['7516'] - ink2r['7517']

  // Financial items: income minus costs
  const financialItems =
    ink2r['7414'] + ink2r['7415'] + ink2r['7423'] + ink2r['7416'] + ink2r['7417']
    - ink2r['7521'] - ink2r['7522']

  // Bokslutsdispositioner: subtract debit-normal, add credit-normal and net
  const bokslutsdispositioner =
    - ink2r['7524'] + ink2r['7419'] + ink2r['7420'] - ink2r['7525']
    + ink2r['7421'] + ink2r['7422']

  // Result before tax
  const resultBeforeTax = operatingResult + financialItems + bokslutsdispositioner

  // Result after tax (7528 is positive, subtract it)
  const resultAfterFinancial = resultBeforeTax - ink2r['7528']

  // Set årets resultat: vinst (7450) or förlust (7550)
  if (resultAfterFinancial >= 0) {
    ink2r['7450'] = resultAfterFinancial
    ink2r['7550'] = 0
  } else {
    ink2r['7450'] = 0
    ink2r['7550'] = Math.abs(resultAfterFinancial)
  }

  // Add calculated result to fritt eget kapital for balance
  // During open fiscal year, 2099 may have no balance — the result only exists
  // as net of income statement accounts. Adding it here handles both cases.
  const adjustedEquityLiabilities = totalEquityLiabilities + resultAfterFinancial

  // Fiscal year dates as YYYYMMDD
  const fyStart = (period.period_start as string).replace(/-/g, '')
  const fyEnd = (period.period_end as string).replace(/-/g, '')

  // Build INK2 (huvudblankett)
  // Auto-derive from INK2S result (simplified: result + non-deductible tax)
  // 7528 is already positive per Skatteverket convention
  const taxAmount = ink2r['7528']
  const taxableResult = resultAfterFinancial + taxAmount

  const ink2: INK2Rutor = {
    '7011': fyStart,
    '7012': fyEnd,
    '7113': taxableResult >= 0 ? taxableResult : 0,
    '7114': taxableResult < 0 ? Math.abs(taxableResult) : 0,
  }

  // Build INK2S (skattemässiga justeringar — auto-derived basics only)
  const ink2s: INK2SRutor = {
    '7011': fyStart,
    '7012': fyEnd,
    '7650': resultAfterFinancial >= 0 ? resultAfterFinancial : 0,
    '7750': resultAfterFinancial < 0 ? Math.abs(resultAfterFinancial) : 0,
    '7651': taxAmount, // Skatt (ej avdragsgill)
    '8020': taxableResult >= 0 ? taxableResult : 0,
    '8021': taxableResult < 0 ? Math.abs(taxableResult) : 0,
  }

  // Add warnings
  if (!(period as FiscalPeriod).is_closed) {
    warnings.push('Räkenskapsåret är inte stängt — deklarationen kan genereras, men siffrorna kan ändras om fler bokföringar görs.')
  }

  if (totalAssets === 0 && totalEquityLiabilities === 0 && ink2r['7410'] === 0) {
    warnings.push('Inga bokförda transaktioner hittades för perioden.')
  }

  const balanceWarning = checkBalanceWarning(totalAssets, adjustedEquityLiabilities)
  if (balanceWarning) {
    warnings.push(balanceWarning)
  }

  return {
    fiscalYear: {
      id: period.id,
      name: period.name,
      start: period.period_start,
      end: period.period_end,
      isClosed: period.is_closed,
    },
    ink2,
    ink2r,
    ink2s,
    breakdown,
    totals: {
      totalAssets,
      totalEquityLiabilities: adjustedEquityLiabilities,
      operatingResult,
      resultAfterFinancial,
    },
    companyInfo: {
      companyName: settings?.company_name || 'Okänt företag',
      orgNumber: settings?.org_number || null,
      addressLine1: settings?.address_line1 || null,
      postalCode: settings?.postal_code || null,
      city: settings?.city || null,
      email: settings?.email || null,
    },
    warnings,
  }
}