/* ============================================================================
 * pspension.js — Optional federal public service pension (PSSA) module.
 *
 * Implements the PSPC-published formula for members with 2+ years of
 * pensionable service (contributed to the pension):
 *
 *   Lifetime annual   = 1.375% × min(avg5, AMPE) × min(S, 35)
 *                     + 2%     × max(0, avg5 − AMPE) × min(S, 35)
 *   Bridge benefit    = 0.625% × min(avg5, AMPE) × min(S, 35)   (pre-65 only;
 *                     payable from retirement, ends at the start of the month
 *                     of the 65th birthday — coincides with CPP/D coverage)
 *   Total pre-65      = 2% × avg5 × min(S, 35)
 *
 * avg5  = average salary over the 5 consecutive years of highest paid service
 *         (modelled as the user-entered figure; AMPE = Average Maximum
 *         Pensionable Earnings — indexed to YMPE, 100% of YMPE since 2010;
 *         we use the current YMPE from canada.js as a real-dollar proxy).
 * S     = years of recognised pensionable service, capped at 35.
 *
 * Early-reduction (annual allowance) decision tree — Group 1 (joined on/after
 * 1999-04-01 and before 2013-01-01; payable from 50):
 *   unreduced if (age ≥ 60 and S ≥ 2) or (age ≥ 55 and S ≥ 30);
 *   F1 (S < 25):  5% × (60 − age)
 *   F2 (S ≥ 25):  max( 5% × (55 − age), 5% × (30 − S) )
 *   age ≥ 55 with S ≥ 25: apply the LOWER of F1 and F2 (PSPC page);
 *   leaving before 50: F1 with age pinned at 50 → 50% reduction cap.
 * Group 2 (joined on/after 2013-01-01; payable from 55):
 *   unreduced if (age ≥ 65 and S ≥ 2) or (age ≥ 60 and S ≥ 30);
 *   F1 (S < 25):  5% × (65 − age)
 *   F2 (S ≥ 25):  max( 5% × (60 − age), 5% × (30 − S) )
 *   age ≥ 60 with S ≥ 25: apply the LOWER of F1 and F2;
 *   leaving before 55: F1 pinned at 55 → 50%; the planner models the
 *   PSPC-default path: deferred annuity, unreduced, payable at 65.
 * Reduction applies to the WHOLE pension (lifetime + bridge); ages/service
 * to the nearest tenth of a year. Under 2 years of service: return of
 * contributions only (no pension).
 *
 * Sources verified 2026-02 (constants re-checked verbatim, page dated 2025-08-15).
 * UMD: window.RetirePS in the browser, module.exports in Node.
 * ==========================================================================*/
(function (root, factory) {
  if (typeof module !== 'undefined' && module.exports) module.exports = factory();
  else root.RetirePS = factory();
})(typeof self !== 'undefined' ? self : this, function () {
  'use strict';

  var PCT_LOW = 0.01375;    // 1.375% — career average up to AMPE
  var PCT_HIGH = 0.02;      // 2%     — career average above AMPE
  var BRIDGE_PCT = 0.00625; // 0.625% — bridge benefit (pre-65), up to AMPE only
  var MAX_SERVICE = 35;     // pensionable-service cap
  var EARLY_PCT = 0.05;     // 5% per year (or part-year, to the tenth)
  var GROUP1_CUTOFF_YEAR = 2012; // joined on/before 2012-12-31 → Group 1
  var MAX_REDUCTION = 0.5;  // 50% cap (F1 at the earliest payable age)

  /* IT (Indian and Northern Government Services) annual rates of pay,
   * TBS "IT" collective agreement, Appendix A, wage-adjustment row
   * effective 2024-12-22. Overridable: the UI exposes these as defaults. */
  var IT_RATES_ASOF = '2024-12-22';
  var IT_RATES_SOURCE = 'https://www.canada.ca/en/treasury-board-secretariat/topics/pay/collective-agreements/it.html';
  var IT_LEVELS = [
    { id: 'IT-01', steps: [69361, 71925, 74485, 77031, 79574, 82120, 84661, 89382] },
    { id: 'IT-02', steps: [85854, 88603, 91348, 94095, 96844, 99589, 102335, 105080] },
    { id: 'IT-03', steps: [101343, 104833, 108324, 111817, 115306, 118791, 122281, 125914] },
    { id: 'IT-04', steps: [116037, 120038, 124039, 128039, 132039, 136041, 140039, 144434] },
    { id: 'IT-05', steps: [133582, 138563, 143539, 148520, 153503, 158485, 163465, 168446, 174076] }
  ];

  var SOURCES = {
    g1En: 'https://www.canada.ca/en/public-services-procurement/services/pay-pension/public-service-pension-plan/retired/entitlement-information-packages/2-more-years-pensionable-service/member-on-before-december-31-2012.html',
    g1Fr: 'https://www.canada.ca/fr/services-publics-approvisionnement/services/paye-pension/regime-retraite-fonction-publique/retraite/trousse-information-presentations/2-ans-plus-service-ouvrant-droit-pension/participant-31-decembre-2012-ou-avant.html',
    g2En: 'https://www.canada.ca/en/public-services-procurement/services/pay-pension/public-service-pension-plan/retired/entitlement-information-packages/2-more-years-pensionable-service/member-on-after-january-1-2013.html',
    g2Fr: 'https://www.canada.ca/fr/services-publics-approvisionnement/services/paye-pension/regime-retraite-fonction-publique/retraite/trousse-information-presentations/2-ans-plus-service-ouvrant-droit-pension/participant-1er-janvier-2013-ou-apres.html',
    glossaryEn: 'https://www.canada.ca/en/treasury-board-secretariat/services/pension-plan/plan-information/glossary.html',
    atAGlanceEn: 'https://www.canada.ca/en/treasury-board-secretariat/services/pension-plan/plan-information/public-service-pension-glance.html',
    ympeCra: 'https://www.canada.ca/en/revenue-agency/services/tax/businesses/topics/payroll/payroll-deductions-contributions/canada-pension-plan-cpp/cpp-enhancement.html',
    splittingCra: 'https://www.canada.ca/en/revenue-agency/services/tax/individuals/topics/pension-income-splitting.html',
    itAgreement: IT_RATES_SOURCE
  };

  function tenth(x) { return Math.round(x * 10) / 10; }
  function round2(x) { return Math.round(x * 100) / 100; }

  /* 1 | 2 from the year the member joined the federal public service. */
  function psGroup(joinYear) {
    var y = +joinYear;
    if (!y) return null;
    return y <= GROUP1_CUTOFF_YEAR ? 1 : 2;
  }

  /* Auto-derive years of pensionable service (PS-AUTO-SERVICE):
   *   yearsWorkedSoFar = currentYear − joinYear
   *   ageAtJoin        = age − yearsWorkedSoFar
   *   serviceYears     = retireAge − ageAtJoin, clamped to [0, 60] (whole years;
   *                      the pension formula applies its own 35-yr MAX_SERVICE cap).
   * currentYear defaults to the calendar year. Returns null when age, joinYear or
   * retireAge is missing/invalid — the UI then falls back to manual entry. */
  function autoServiceYears(age, joinYear, retireAge, currentYear) {
    var y = +currentYear;
    if (!(y > 0)) y = new Date().getFullYear();
    var a = +age, j = +joinYear, r = +retireAge;
    if (!(a > 0) || !(r > 0) || !(y > 0)) return null;
    if (!(j >= 1900 && j <= 2999)) return null;
    if (!isFinite(a) || !isFinite(j) || !isFinite(r) || !isFinite(y)) return null;
    var joinAge = a - (y - j);
    var s = r - joinAge;
    return Math.round(Math.max(0, Math.min(60, s)));
  }

  function itLevel(id) {
    for (var i = 0; i < IT_LEVELS.length; i++) if (IT_LEVELS[i].id === id) return IT_LEVELS[i];
    return null;
  }
  function itRange(id) {
    var lv = itLevel(id);
    if (!lv) return null;
    return { min: lv.steps[0], top: lv.steps[lv.steps.length - 1], steps: lv.steps, asof: IT_RATES_ASOF };
  }

  /* Early-reduction (annual allowance) per the PSPC decision tree.
   * Returns { unreduced, pct, formula: 'F1'|'F2'|'min(F1,F2)'|null, note }
   * with pct in [0, 0.5]; ages/service to the nearest tenth (PSPC).
   * note keys: 'unreduced' | 'f1Under50' | 'f1Under55' (fixed-age rules). */
  function psEarlyReduction(group, retireAge, serviceYears) {
    var age = tenth(+retireAge), S = tenth(+serviceYears);
    var g = +group === 2 ? 2 : 1;
    var R = function (pct, formula, unreduced, note) {
      return { unreduced: !!unreduced, pct: pct, formula: formula, note: note || null };
    };
    if (g === 1) {
      if (age >= 60 || (age >= 55 && S >= 30)) return R(0, null, true, 'unreduced');
      var f1 = EARLY_PCT * Math.max(0, 60 - age);
      if (age < 50) return R(MAX_REDUCTION, 'F1', false, 'f1Under50');  // payable from 50, age pinned at 50
      if (S < 25) return R(Math.min(MAX_REDUCTION, f1), 'F1', false, null);
      var f2a = Math.max(0, EARLY_PCT * (55 - age)), f2b = Math.max(0, EARLY_PCT * (30 - S));
      var f2 = Math.max(f2a, f2b);
      if (age >= 55) return R(Math.min(MAX_REDUCTION, Math.min(f1, f2)), 'min(F1,F2)', false, null);
      return R(Math.min(MAX_REDUCTION, f2), 'F2', false, null);
    }
    if (age >= 65 || (age >= 60 && S >= 30)) return R(0, null, true, 'unreduced');
    var g1 = EARLY_PCT * Math.max(0, 65 - age);
    if (age < 55) return R(MAX_REDUCTION, 'F1', false, 'f1Under55');    // payable from 55, age pinned at 55
    if (S < 25) return R(Math.min(MAX_REDUCTION, g1), 'F1', false, null);
    var h2a = Math.max(0, EARLY_PCT * (60 - age)), h2b = Math.max(0, EARLY_PCT * (30 - S));
    var h2 = Math.max(h2a, h2b);
    if (age >= 60) return R(Math.min(MAX_REDUCTION, Math.min(g1, h2)), 'min(F1,F2)', false, null);
    return R(Math.min(MAX_REDUCTION, h2), 'F2', false, null);
  }

  /* Lifetime annual pension (years capped at 35 by the caller's service). */
  function psLifetimePension(avgSalary, ampe, years) {
    var Sc = Math.min(tenth(+years || 0), MAX_SERVICE);
    var capAvg = Math.min(Math.max(0, +avgSalary || 0), Math.max(0, +ampe || 0));
    var over = Math.max(0, (+avgSalary || 0) - (+ampe || 0));
    return round2(PCT_LOW * capAvg * Sc + PCT_HIGH * over * Sc);
  }
  /* Bridge benefit: 0.625% × min(avg,AMPE) × min(S,35) — caller zeroes at 65+. */
  function psBridgeBenefit(avgSalary, ampe, years) {
    var Sc = Math.min(tenth(+years || 0), MAX_SERVICE);
    var capAvg = Math.min(Math.max(0, +avgSalary || 0), Math.max(0, +ampe || 0));
    return round2(BRIDGE_PCT * capAvg * Sc);
  }

  /* Full benefit computation.
   * Input:  { joinYear, retireAge, serviceYears, avgSalary, ampe }
   * Output (plan contract): { group, serviceCapped, lifetime, bridge,
   *   reductionPct, formula, pensionAtRetirement, pensionFrom65, startAge,
   *   deferred, earlyOnlyNote, notes[] } — $ annual, to the cent. */
  function computePSPension(o) {
    o = o || {};
    var avg = Math.max(0, +o.avgSalary || 0);
    var ampe = Math.max(0, +o.ampe || 0);
    var S = tenth(+o.serviceYears || 0);
    var age = tenth(+o.retireAge || 0);
    var group = +o.group === 1 || +o.group === 2 ? +o.group : psGroup(o.joinYear) || 1;
    var Sc = Math.min(S, MAX_SERVICE);
    var lifetime = psLifetimePension(avg, ampe, Sc);
    var out = {
      group: group, serviceCapped: Sc, startAge: age, deferred: false,
      lifetime: lifetime, bridge: 0,
      reductionPct: 0, formula: null,
      pensionAtRetirement: lifetime, pensionFrom65: lifetime,
      earlyOnlyNote: null, notes: []
    };
    if (S < 2) {  // return of contributions only — no annuity (PSPC)
      out.lifetime = 0; out.pensionAtRetirement = 0; out.pensionFrom65 = 0;
      out.notes.push('lt2');
      return out;
    }
    var red = { pct: 0, formula: null };
    if (group === 2 && age < 55) {
      // PSPC default (no election within 1 year): deferred annuity, unreduced, at 65.
      out.deferred = true; out.startAge = 65;
      red = { pct: 0, formula: null };
      out.earlyOnlyNote = 'deferredG2';
    } else {
      red = psEarlyReduction(group, age, S);
      out.startAge = age;
      if (red.note === 'f1Under50') { out.startAge = 50; out.notes.push('f1Under50'); }
      if (red.note === 'f1Under55') { out.startAge = 55; out.notes.push('f1Under55'); }
    }
    out.reductionPct = red.pct;
    out.formula = red.formula;
    out.bridge = out.startAge < 65 ? psBridgeBenefit(avg, ampe, Sc) : 0;
    out.pensionAtRetirement = round2((out.lifetime + out.bridge) * (1 - out.reductionPct));
    out.pensionFrom65 = round2(out.lifetime * (1 - out.reductionPct));
    return out;
  }

  return {
    PCT_LOW: PCT_LOW, PCT_HIGH: PCT_HIGH, BRIDGE_PCT: BRIDGE_PCT,
    MAX_SERVICE: MAX_SERVICE, GROUP1_CUTOFF_YEAR: GROUP1_CUTOFF_YEAR,
    IT_LEVELS: IT_LEVELS, IT_RATES_ASOF: IT_RATES_ASOF, IT_RATES_SOURCE: IT_RATES_SOURCE,
    SOURCES: SOURCES,
    psGroup: psGroup, psLifetimePension: psLifetimePension,
    psBridgeBenefit: psBridgeBenefit, psEarlyReduction: psEarlyReduction,
    computePSPension: computePSPension, autoServiceYears: autoServiceYears,
    itLevel: itLevel, itRange: itRange
  };
});