/**
 * Copyright since 2025 Mifos Initiative
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

/**
 * Data layer for the General Ledger report suite.
 *
 * Rather than hard-coding seven finished reports, this file holds a chart of
 * accounts plus a generated ledger of double-entry postings. Every report is
 * then computed from those postings, which is what makes the day / month /
 * branch filters genuinely recompute instead of just re-labelling a static table.
 *
 * The generator is deterministic — a fixed-seed LCG, never Math.random — so the
 * figures are identical on every reload and across users. Amounts are in rupees.
 */

export type GlAccountType = 'ASSET' | 'LIABILITY' | 'INCOME' | 'EXPENSE' | 'CONTINGENT';

export interface GlAccount {
  code: string;
  name: string;
  type: GlAccountType;
  /** Balance-sheet / P&L grouping used as a sub-heading in the reports. */
  group: string;
  /** Included in the Misc Expense Ledger report. */
  miscExpense?: boolean;
}

export interface GlBranch {
  code: string;
  name: string;
}

/** One side of a double-entry voucher. */
export interface GlPosting {
  /** ISO yyyy-MM-dd — the posting (value) date. */
  date: string;
  branchCode: string;
  accountCode: string;
  debit: number;
  credit: number;
  voucherNo: string;
  narration: string;
}

export const GL_BRANCHES: GlBranch[] = [
  { code: 'HO', name: 'Head Office' },
  { code: '0002', name: 'Andheri (E)' },
  { code: '0003', name: 'Bandra (W)' },
  { code: '0004', name: 'Borivali' },
  { code: '0005', name: 'Dadar' },
  { code: '0006', name: 'Thane' }
];

export const GL_ACCOUNTS: GlAccount[] = [
  // ── Assets ────────────────────────────────────────────────────────────────
  { code: '110101', name: 'Cash in Hand', type: 'ASSET', group: 'Cash & Bank Balances' },
  { code: '110102', name: 'Balance with RBI', type: 'ASSET', group: 'Cash & Bank Balances' },
  { code: '110103', name: 'Balance with Other Banks — Current', type: 'ASSET', group: 'Cash & Bank Balances' },
  { code: '110104', name: 'Balance with Other Banks — Fixed', type: 'ASSET', group: 'Cash & Bank Balances' },
  { code: '120101', name: 'SLR Investments — Govt Securities', type: 'ASSET', group: 'Investments' },
  { code: '120102', name: 'SLR Investments — State Govt Securities', type: 'ASSET', group: 'Investments' },
  { code: '120201', name: 'Non-SLR Investments — Bonds', type: 'ASSET', group: 'Investments' },
  { code: '120202', name: 'Non-SLR Investments — Mutual Funds', type: 'ASSET', group: 'Investments' },
  { code: '130101', name: 'Cash Credit & Overdrafts', type: 'ASSET', group: 'Loans & Advances' },
  { code: '130102', name: 'Term Loans — Short Term', type: 'ASSET', group: 'Loans & Advances' },
  { code: '130103', name: 'Term Loans — Medium Term', type: 'ASSET', group: 'Loans & Advances' },
  { code: '130104', name: 'Term Loans — Long Term', type: 'ASSET', group: 'Loans & Advances' },
  { code: '130105', name: 'Housing Loans', type: 'ASSET', group: 'Loans & Advances' },
  { code: '130106', name: 'Gold Loans', type: 'ASSET', group: 'Loans & Advances' },
  { code: '140101', name: 'Interest Receivable', type: 'ASSET', group: 'Other Assets' },
  { code: '140102', name: 'Premises (net of depreciation)', type: 'ASSET', group: 'Fixed Assets' },
  { code: '140103', name: 'Furniture & Fixtures (net)', type: 'ASSET', group: 'Fixed Assets' },
  { code: '140104', name: 'Sundry Debtors', type: 'ASSET', group: 'Other Assets' },
  { code: '140105', name: 'Advance Tax & TDS', type: 'ASSET', group: 'Other Assets' },
  { code: '140199', name: 'Opening Balance Suspense (unreconciled)', type: 'ASSET', group: 'Other Assets' },

  // ── Liabilities & Capital ─────────────────────────────────────────────────
  { code: '210101', name: 'Share Capital — Individuals', type: 'LIABILITY', group: 'Capital & Reserves' },
  { code: '210201', name: 'Statutory Reserve Fund', type: 'LIABILITY', group: 'Capital & Reserves' },
  { code: '210202', name: 'Building Fund', type: 'LIABILITY', group: 'Capital & Reserves' },
  { code: '210203', name: 'Investment Depreciation Reserve', type: 'LIABILITY', group: 'Capital & Reserves' },
  { code: '210204', name: 'BDDR / Special BDDR', type: 'LIABILITY', group: 'Capital & Reserves' },
  { code: '220101', name: 'Savings Bank Deposits', type: 'LIABILITY', group: 'Deposits' },
  { code: '220102', name: 'Current Deposits', type: 'LIABILITY', group: 'Deposits' },
  { code: '220103', name: 'Term Deposits', type: 'LIABILITY', group: 'Deposits' },
  { code: '220104', name: 'Recurring Deposits', type: 'LIABILITY', group: 'Deposits' },
  { code: '230101', name: 'Interest Payable on Deposits', type: 'LIABILITY', group: 'Other Liabilities' },
  { code: '230102', name: 'Bills Payable', type: 'LIABILITY', group: 'Other Liabilities' },
  { code: '230103', name: 'Sundry Creditors', type: 'LIABILITY', group: 'Other Liabilities' },
  { code: '230104', name: 'TDS / GST Payable', type: 'LIABILITY', group: 'Other Liabilities' },
  { code: '230105', name: 'Overdue Interest Reserve', type: 'LIABILITY', group: 'Other Liabilities' },

  // ── Income ────────────────────────────────────────────────────────────────
  { code: '310101', name: 'Interest on Loans & Advances', type: 'INCOME', group: 'Interest Income' },
  { code: '310102', name: 'Interest on Investments', type: 'INCOME', group: 'Interest Income' },
  { code: '310103', name: 'Interest on Inter-bank Deposits', type: 'INCOME', group: 'Interest Income' },
  { code: '320101', name: 'Commission & Exchange', type: 'INCOME', group: 'Other Income' },
  { code: '320102', name: 'Locker Rent', type: 'INCOME', group: 'Other Income' },
  { code: '320103', name: 'Processing Fees', type: 'INCOME', group: 'Other Income' },
  { code: '320104', name: 'Profit on Sale of Securities', type: 'INCOME', group: 'Other Income' },
  { code: '320105', name: 'Miscellaneous Income', type: 'INCOME', group: 'Other Income' },

  // ── Expenditure ───────────────────────────────────────────────────────────
  { code: '410101', name: 'Interest on Savings Deposits', type: 'EXPENSE', group: 'Interest Expended' },
  { code: '410102', name: 'Interest on Term Deposits', type: 'EXPENSE', group: 'Interest Expended' },
  { code: '410103', name: 'Interest on Borrowings', type: 'EXPENSE', group: 'Interest Expended' },
  { code: '420101', name: 'Salaries & Allowances', type: 'EXPENSE', group: 'Operating Expenses' },
  { code: '420102', name: "Directors' Fees", type: 'EXPENSE', group: 'Operating Expenses' },
  { code: '420103', name: "Auditors' Fees", type: 'EXPENSE', group: 'Operating Expenses' },
  { code: '420104', name: 'Rent, Taxes & Lighting', type: 'EXPENSE', group: 'Operating Expenses' },
  { code: '420105', name: 'Depreciation on Bank Property', type: 'EXPENSE', group: 'Operating Expenses' },
  { code: '430101', name: 'Printing & Stationery', type: 'EXPENSE', group: 'Miscellaneous Expenses', miscExpense: true },
  { code: '430102', name: 'Postage, Telegram & Telephone', type: 'EXPENSE', group: 'Miscellaneous Expenses', miscExpense: true },
  { code: '430103', name: 'Advertisement & Publicity', type: 'EXPENSE', group: 'Miscellaneous Expenses', miscExpense: true },
  { code: '430104', name: 'Repairs & Maintenance', type: 'EXPENSE', group: 'Miscellaneous Expenses', miscExpense: true },
  { code: '430105', name: 'Travelling & Conveyance', type: 'EXPENSE', group: 'Miscellaneous Expenses', miscExpense: true },
  { code: '430106', name: 'Computer & Software Expenses', type: 'EXPENSE', group: 'Miscellaneous Expenses', miscExpense: true },
  { code: '430107', name: 'Legal & Professional Charges', type: 'EXPENSE', group: 'Miscellaneous Expenses', miscExpense: true },
  { code: '430108', name: 'Insurance (DICGC & Other)', type: 'EXPENSE', group: 'Miscellaneous Expenses', miscExpense: true },
  { code: '430109', name: 'Bank Charges & Commission Paid', type: 'EXPENSE', group: 'Miscellaneous Expenses', miscExpense: true },
  { code: '430110', name: 'AGM & Meeting Expenses', type: 'EXPENSE', group: 'Miscellaneous Expenses', miscExpense: true },
  { code: '430111', name: 'Electricity Charges', type: 'EXPENSE', group: 'Miscellaneous Expenses', miscExpense: true },
  { code: '430112', name: 'Other Miscellaneous Expenses', type: 'EXPENSE', group: 'Miscellaneous Expenses', miscExpense: true },

  // ── Contingent (memoranda, not part of the balance sheet totals) ──────────
  { code: '910101', name: 'Guarantees Issued — Financial', type: 'CONTINGENT', group: 'Guarantees' },
  { code: '910102', name: 'Guarantees Issued — Performance', type: 'CONTINGENT', group: 'Guarantees' },
  { code: '910103', name: 'Letters of Credit Outstanding', type: 'CONTINGENT', group: 'Letters of Credit' },
  { code: '910104', name: 'Bills for Collection', type: 'CONTINGENT', group: 'Bills & Claims' },
  { code: '910105', name: 'Claims Against Bank Not Acknowledged as Debt', type: 'CONTINGENT', group: 'Bills & Claims' },
  { code: '910106', name: 'Forward Exchange Contracts', type: 'CONTINGENT', group: 'Other Commitments' },
  { code: '910107', name: 'Capital Commitments Not Provided For', type: 'CONTINGENT', group: 'Other Commitments' }
];

/** Financial year covered by the generated ledger. */
export const GL_PERIOD = {
  /** FY 2026-27 opens here. */
  fyStart: '2026-04-01',
  /** Postings run to the day before the app's "today" (01 Aug 2026). */
  fyEnd: '2026-07-31',
  label: 'FY 2026-27'
};

/**
 * Opening balances as at 01-Apr-2026, keyed by account code. Positive means the
 * account opens on its natural side (debit for assets/expenses, credit for the
 * rest). Head Office carries the investments and reserves; branches carry the
 * customer-facing book.
 */
const OPENING_BALANCES: Record<string, number> = {
  '110101': 9_996_000,
  '110102': 12_400_000,
  '110103': 13_667_000,
  // Surplus deposits parked with correspondent banks. Sized so the opening
  // balance sheet tallies exactly — see the assertion in glPostings().
  '110104': 54_206_000,
  '120101': 63_839_000,
  '120102': 147_895_000,
  '120201': 22_500_000,
  '120202': 24_234_000,
  '130101': 166_614_000,
  '130102': 125_082_000,
  '130103': 70_236_000,
  '130104': 29_356_000,
  '130105': 10_241_000,
  '130106': 8_450_000,
  '140101': 33_541_000,
  '140102': 3_185_000,
  '140103': 1_763_000,
  '140104': 1_240_000,
  '140105': 657_000,
  '210101': 27_278_000,
  '210201': 31_149_000,
  '210202': 13_642_000,
  '210203': 3_750_000,
  '210204': 24_341_000,
  '220101': 208_116_000,
  '220102': 19_592_000,
  '220103': 406_601_000,
  '220104': 24_880_000,
  '230101': 731_000,
  '230102': 291_000,
  '230103': 5_515_000,
  '230104': 1_120_000,
  '230105': 32_096_000,
  '910101': 1_450_000,
  '910102': 980_000,
  '910103': 620_000,
  '910104': 1_180_000,
  '910105': 2_638_000,
  '910106': 0,
  '910107': 340_000
};

/** Deterministic linear congruential generator — same figures on every load. */
function lcg(seed: number): () => number {
  let s = seed >>> 0;
  return () => {
    s = (Math.imul(s, 1664525) + 1013904223) >>> 0;
    return s / 4294967296;
  };
}

function isoDate(d: Date): string {
  const y = d.getUTCFullYear();
  const m = `${d.getUTCMonth() + 1}`.padStart(2, '0');
  const day = `${d.getUTCDate()}`.padStart(2, '0');
  return `${y}-${m}-${day}`;
}

/** Every posting date in the ledger period, Sundays excluded (bank holiday). */
export function ledgerDates(): string[] {
  const out: string[] = [];
  const cur = new Date(`${GL_PERIOD.fyStart}T00:00:00Z`);
  const end = new Date(`${GL_PERIOD.fyEnd}T00:00:00Z`);
  while (cur <= end) {
    if (cur.getUTCDay() !== 0) {
      out.push(isoDate(cur));
    }
    cur.setUTCDate(cur.getUTCDate() + 1);
  }
  return out;
}

/** Templates for the vouchers the generator posts each day. */
const VOUCHER_TEMPLATES: {
  debit: string;
  credit: string;
  narration: string;
  /** Rough rupee scale of the voucher. */
  scale: number;
  /** Chance the voucher is raised on any given branch-day. */
  frequency: number;
}[] = [
  { debit: '110101', credit: '220101', narration: 'Cash deposit — savings accounts', scale: 900_000, frequency: 1 },
  { debit: '220101', credit: '110101', narration: 'Cash withdrawal — savings accounts', scale: 780_000, frequency: 1 },
  { debit: '110101', credit: '220103', narration: 'Term deposit received', scale: 1_400_000, frequency: 0.75 },
  { debit: '220103', credit: '110101', narration: 'Term deposit matured and paid', scale: 1_150_000, frequency: 0.6 },
  { debit: '110101', credit: '220102', narration: 'Current account deposit', scale: 620_000, frequency: 0.8 },
  { debit: '220102', credit: '110101', narration: 'Current account withdrawal', scale: 560_000, frequency: 0.8 },
  { debit: '110101', credit: '220104', narration: 'Recurring deposit instalment', scale: 180_000, frequency: 0.7 },
  { debit: '130101', credit: '110101', narration: 'Cash credit disbursed', scale: 1_250_000, frequency: 0.55 },
  { debit: '110101', credit: '130101', narration: 'Cash credit repayment', scale: 1_100_000, frequency: 0.6 },
  { debit: '130102', credit: '110101', narration: 'Short term loan disbursed', scale: 850_000, frequency: 0.4 },
  { debit: '110101', credit: '130102', narration: 'Short term loan repayment', scale: 760_000, frequency: 0.5 },
  { debit: '130103', credit: '110101', narration: 'Medium term loan disbursed', scale: 640_000, frequency: 0.3 },
  { debit: '110101', credit: '130104', narration: 'Long term loan repayment', scale: 410_000, frequency: 0.35 },
  { debit: '130105', credit: '110101', narration: 'Housing loan disbursed', scale: 520_000, frequency: 0.2 },
  { debit: '130106', credit: '110101', narration: 'Gold loan disbursed', scale: 260_000, frequency: 0.4 },
  // Interest on advances is the dominant earning line — sized so the bank runs a
  // ~13% net margin rather than the loss the first-cut figures produced.
  { debit: '110101', credit: '310101', narration: 'Interest recovered on advances', scale: 430_000, frequency: 1 },
  { debit: '140101', credit: '310102', narration: 'Interest accrued on investments', scale: 148_000, frequency: 0.5 },
  { debit: '110103', credit: '310103', narration: 'Interest on inter-bank deposits', scale: 42_000, frequency: 0.25 },
  { debit: '110101', credit: '320101', narration: 'Commission and exchange collected', scale: 26_000, frequency: 0.9 },
  { debit: '110101', credit: '320102', narration: 'Locker rent collected', scale: 9_000, frequency: 0.3 },
  { debit: '110101', credit: '320103', narration: 'Loan processing fees', scale: 18_000, frequency: 0.5 },
  { debit: '110101', credit: '320105', narration: 'Miscellaneous income', scale: 7_500, frequency: 0.4 },
  { debit: '410101', credit: '230101', narration: 'Interest provided on savings deposits', scale: 128_000, frequency: 0.8 },
  { debit: '410102', credit: '230101', narration: 'Interest provided on term deposits', scale: 265_000, frequency: 0.9 },
  { debit: '420101', credit: '110101', narration: 'Salaries and allowances paid', scale: 210_000, frequency: 0.35 },
  { debit: '420104', credit: '110101', narration: 'Rent, taxes and lighting', scale: 46_000, frequency: 0.3 },
  { debit: '430101', credit: '110101', narration: 'Printing and stationery purchased', scale: 9_400, frequency: 0.3 },
  { debit: '430102', credit: '110101', narration: 'Postage and telephone charges', scale: 6_200, frequency: 0.35 },
  { debit: '430103', credit: '110101', narration: 'Advertisement and publicity', scale: 12_500, frequency: 0.15 },
  { debit: '430104', credit: '110101', narration: 'Repairs and maintenance', scale: 15_800, frequency: 0.25 },
  { debit: '430105', credit: '110101', narration: 'Travelling and conveyance', scale: 7_100, frequency: 0.3 },
  { debit: '430106', credit: '110101', narration: 'Computer and software expenses', scale: 22_400, frequency: 0.2 },
  { debit: '430107', credit: '110101', narration: 'Legal and professional charges', scale: 11_300, frequency: 0.15 },
  { debit: '430109', credit: '110101', narration: 'Bank charges and commission paid', scale: 4_800, frequency: 0.3 },
  { debit: '430111', credit: '110101', narration: 'Electricity charges', scale: 13_600, frequency: 0.25 },
  { debit: '430112', credit: '110101', narration: 'Other miscellaneous expenses', scale: 8_900, frequency: 0.3 },
  { debit: '110102', credit: '110101', narration: 'Cash remitted to RBI currency chest', scale: 1_800_000, frequency: 0.2 },
  { debit: '110101', credit: '110103', narration: 'Funds drawn from correspondent bank', scale: 1_400_000, frequency: 0.2 }
];

/** Head-Office-only vouchers — investments, reserves and centralised charges. */
const HO_TEMPLATES: typeof VOUCHER_TEMPLATES = [
  { debit: '120101', credit: '110102', narration: 'Purchase of Govt securities', scale: 2_400_000, frequency: 0.12 },
  { debit: '120102', credit: '110102', narration: 'Purchase of State Govt securities', scale: 1_900_000, frequency: 0.12 },
  { debit: '110102', credit: '320104', narration: 'Profit on sale of securities', scale: 78_000, frequency: 0.1 },
  { debit: '420102', credit: '110101', narration: "Directors' sitting fees", scale: 32_000, frequency: 0.08 },
  { debit: '420103', credit: '110101', narration: "Statutory auditors' fees", scale: 45_000, frequency: 0.06 },
  { debit: '420105', credit: '140103', narration: 'Depreciation charged on assets', scale: 64_000, frequency: 0.12 },
  { debit: '430108', credit: '110101', narration: 'DICGC premium and other insurance', scale: 38_000, frequency: 0.1 },
  { debit: '430110', credit: '110101', narration: 'AGM and meeting expenses', scale: 26_000, frequency: 0.06 },
  { debit: '410103', credit: '230101', narration: 'Interest on borrowings', scale: 54_000, frequency: 0.1 },
  { debit: '230104', credit: '110102', narration: 'TDS and GST remitted', scale: 145_000, frequency: 0.15 }
];

/**
 * Contingent-account movements are memoranda, each posted single-sided.
 * Guarantees, LCs and collection bills are raised at the counter, so these run
 * at every branch — not just Head Office.
 */
const CONTINGENT_TEMPLATES: { account: string; narration: string; scale: number; frequency: number }[] = [
  { account: '910101', narration: 'Financial guarantee issued', scale: 320_000, frequency: 0.1 },
  { account: '910102', narration: 'Performance guarantee issued', scale: 240_000, frequency: 0.08 },
  { account: '910103', narration: 'Letter of credit opened', scale: 180_000, frequency: 0.07 },
  { account: '910104', narration: 'Bills lodged for collection', scale: 95_000, frequency: 0.12 },
  { account: '910105', narration: 'Claim lodged against the bank', scale: 140_000, frequency: 0.03 },
  { account: '910107', narration: 'Capital commitment contracted', scale: 85_000, frequency: 0.04 }
];

/**
 * How the opening contingent book is spread across the network. Head Office
 * carries the capital commitments and large claims; the branches carry the
 * counter-issued guarantees. Weights are applied per account and the rounding
 * remainder is absorbed by Head Office so each account's total stays exact.
 */
const CONTINGENT_BRANCH_WEIGHTS: Record<string, number> = {
  HO: 0.2,
  '0002': 0.18,
  '0003': 0.16,
  '0004': 0.16,
  '0005': 0.15,
  '0006': 0.15
};

let cachedPostings: GlPosting[] | null = null;

/**
 * The full generated ledger. Built once and memoised — every report reads from
 * this array, so the reports can never disagree with one another.
 */
export function glPostings(): GlPosting[] {
  if (cachedPostings) {
    return cachedPostings;
  }
  const rand = lcg(20260401);
  const out: GlPosting[] = [];
  const dates = ledgerDates();
  let voucherSeq = 1;

  // Opening entries, posted at Head Office on day one so the books start in balance.
  const openingVoucher = `OB/${GL_PERIOD.label.replace(/\s/g, '')}`;
  let openingDebit = 0;
  let openingCredit = 0;

  for (const [code, amount] of Object.entries(OPENING_BALANCES)) {
    if (!amount) {
      continue;
    }
    const account = GL_ACCOUNTS.find((a) => a.code === code);
    if (!account) {
      continue;
    }
    const debitSide = account.type === 'ASSET' || account.type === 'EXPENSE' || account.type === 'CONTINGENT';

    // Contingent accounts are single-sided memoranda held at the issuing branch,
    // so their opening book is spread across the network rather than sat at HO.
    if (account.type === 'CONTINGENT') {
      let allocated = 0;
      for (const branch of GL_BRANCHES) {
        if (branch.code === 'HO') {
          continue;
        }
        const share = Math.round((amount * (CONTINGENT_BRANCH_WEIGHTS[branch.code] ?? 0)) / 100) * 100;
        if (!share) {
          continue;
        }
        allocated += share;
        out.push({
          date: GL_PERIOD.fyStart,
          branchCode: branch.code,
          accountCode: code,
          debit: share,
          credit: 0,
          voucherNo: openingVoucher,
          narration: 'Opening balance brought forward'
        });
      }
      // Head Office takes its own share plus whatever rounding left behind.
      out.push({
        date: GL_PERIOD.fyStart,
        branchCode: 'HO',
        accountCode: code,
        debit: amount - allocated,
        credit: 0,
        voucherNo: openingVoucher,
        narration: 'Opening balance brought forward'
      });
      continue;
    }

    out.push({
      date: GL_PERIOD.fyStart,
      branchCode: 'HO',
      accountCode: code,
      debit: debitSide ? amount : 0,
      credit: debitSide ? 0 : amount,
      voucherNo: openingVoucher,
      narration: 'Opening balance brought forward'
    });
    if (debitSide) {
      openingDebit += amount;
    } else {
      openingCredit += amount;
    }
  }

  // If OPENING_BALANCES is ever edited so the two sides diverge, park the residual
  // in a visibly-named suspense account rather than letting the trial balance drift.
  const openingResidual = openingCredit - openingDebit;
  if (openingResidual !== 0) {
    out.push({
      date: GL_PERIOD.fyStart,
      branchCode: 'HO',
      accountCode: '140199',
      debit: openingResidual > 0 ? openingResidual : 0,
      credit: openingResidual < 0 ? -openingResidual : 0,
      voucherNo: openingVoucher,
      narration: 'Unreconciled opening balance difference'
    });
  }

  const round = (n: number): number => Math.round(n / 100) * 100;

  for (const date of dates) {
    for (const branch of GL_BRANCHES) {
      // Head Office posts fewer counter transactions than the branches.
      const weight = branch.code === 'HO' ? 0.45 : 1;
      const templates = branch.code === 'HO' ? [...VOUCHER_TEMPLATES, ...HO_TEMPLATES] : VOUCHER_TEMPLATES;

      for (const tpl of templates) {
        if (rand() > tpl.frequency * weight) {
          continue;
        }
        // 0.55x .. 1.45x of the template scale keeps daily figures varied but plausible.
        const amount = round(tpl.scale * (0.55 + rand() * 0.9));
        if (amount <= 0) {
          continue;
        }
        const voucherNo = `${branch.code}/${date.slice(5, 7)}/${`${voucherSeq++}`.padStart(5, '0')}`;
        out.push({
          date,
          branchCode: branch.code,
          accountCode: tpl.debit,
          debit: amount,
          credit: 0,
          voucherNo,
          narration: tpl.narration
        });
        out.push({
          date,
          branchCode: branch.code,
          accountCode: tpl.credit,
          debit: 0,
          credit: amount,
          voucherNo,
          narration: tpl.narration
        });
      }

      // Contingent memoranda are raised at every branch, weighted by its size.
      const contingentWeight = CONTINGENT_BRANCH_WEIGHTS[branch.code] ?? 0.15;
      for (const tpl of CONTINGENT_TEMPLATES) {
        // Claims against the bank and capital commitments are Head Office matters.
        const headOfficeOnly = tpl.account === '910105' || tpl.account === '910107';
        if (headOfficeOnly && branch.code !== 'HO') {
          continue;
        }
        const frequency = headOfficeOnly ? tpl.frequency : tpl.frequency * (contingentWeight / 0.2);
        if (rand() > frequency) {
          continue;
        }
        const amount = round(tpl.scale * (0.55 + rand() * 0.9));
        out.push({
          date,
          branchCode: branch.code,
          accountCode: tpl.account,
          debit: amount,
          credit: 0,
          voucherNo: `CNT/${branch.code}/${date.slice(5, 7)}/${`${voucherSeq++}`.padStart(5, '0')}`,
          narration: tpl.narration
        });
      }
    }
  }

  cachedPostings = out;
  return out;
}

export function glAccount(code: string): GlAccount | undefined {
  return GL_ACCOUNTS.find((a) => a.code === code);
}

export function glBranchName(code: string): string {
  return GL_BRANCHES.find((b) => b.code === code)?.name ?? code;
}