// Build site/engine/canada.js from fetched 2025/2026 sources (PLAN.md Stage 1).
// Sources: CRA current-year (2026) tax-rates page (fetched 2026 via harness), ESDC quarterly
// report Apr-Jun 2026, OAS payments page (Oct-Dec 2026 block), OAS recovery-tax page,
// taxtips.ca province pages (brackets 2026+2025, BPA, surtax FAQ, QC brackets).
const fs = require("fs");
const path = require("path");
const FETCH = path.join(__dirname, "..", ".fetch");
const OUT = path.join(__dirname, "..", "site", "engine", "canada.js");

const ASOF_CRA = "2026-06-25"; // CRA current-year (2026) page publish
const ASOF_ESDC = "2026-04-01"; // quarterly report Apr-Jun 2026 (CPP 2026 figures)
const ASOF_OAS = "2026-09-29"; // payments page Oct-Dec 2026 block
const ASOF_TT = "2026-02-22"; // taxtips dateModified (fetched today)

function num(s) { return Number(String(s).replace(/[$,\s]/g, "")); }

// ---------- province tables (taxtips) ----------
function provinceTable(p) {
  const html = fs.readFileSync(path.join(FETCH, "tt_" + p + ".htm"), "utf8");
  const first = html.match(/<table[\s\S]*?<\/table>/i); // province table is first on page
  if (!first) return [];
  const rows = [...first[0].matchAll(/<tr[^>]*>([\s\S]*?)<\/tr>/gi)];
  const out = [];
  for (const tr of rows) {
    const cells = [...tr[1].matchAll(/<td[^>]*>([\s\S]*?)<\/td>/gi)]
      .map(c => c[1].replace(/<[^>]+>/g, " ").replace(/&nbsp;/g, " ").replace(/\s+/g, " ").trim());
    if (cells.length < 2) continue;
    // data row: [income26, rate26, income25, rate25, ...]
    const income26 = cells[0], rate26 = cells[1];
    let m;
    if ((m = income26.match(/^first \$([\d,]+)$/i))) out.push({ up: num(m[1]), rate: rate26 });
    else if ((m = income26.match(/^over \$[\d,]+ up to \$([\d,]+)$/i))) out.push({ up: num(m[1]), rate: rate26 });
    else if ((m = income26.match(/^over \$([\d,]+)$/i))) out.push({ up: null, rate: rate26 });
  }
  return out.map(r => ({ up: r.up, rate: parseFloat(r.rate) / 100 }));
}
function faqBPA(p) {
  const t = fs.readFileSync(path.join(FETCH, "tt_" + p + ".htm"), "utf8")
    .replace(/<[^>]+>/g, " ").replace(/&nbsp;/g, " ").replace(/&#\d+;/g, " ")
    .replace(/&amp;/g, "&").replace(/\s+/g, " ");
  const m = t.match(/basic personal amount for 2026 is \$([\d,]+)/i) ||
            t.match(/Basic Personal Amount 2026[^$]{0,200}\$([\d,]+)/i);
  return m ? num(m[1]) : null;
}

const fed2026 = [
  { up: 58523, rate: 0.14 }, { up: 117045, rate: 0.205 }, { up: 181440, rate: 0.26 },
  { up: 258482, rate: 0.29 }, { up: null, rate: 0.33 }
];

const provIds = {
  on: "Ontario", bc: "British Columbia", ab: "Alberta", mb: "Manitoba", sk: "Saskatchewan",
  ns: "Nova Scotia", nb: "New Brunswick", nl: "Newfoundland & Labrador", pe: "Prince Edward Island",
  yt: "Yukon", nt: "Northwest Territories", nu: "Nunavut", qc: "Quebec"
};
const prov = {};
for (const [id, name] of Object.entries(provIds)) {
  const brackets = provinceTable(id);
  if (!brackets.length) throw new Error("no brackets parsed for " + id);
  const e = {
    name,
    brackets,
    bpa: faqBPA(id),
    source: "taxtips.ca/taxrates/" + id + ".htm (2026 table)",
    asOf: ASOF_TT
  };
  if (id === "on") e.surtax = [{ from: 6474, rate: 0.20 }, { from: 8102, rate: 0.36 }];
  if (id === "yt") e.bpa = 16452; // YT BPA tracks federal 2026 max (min/max table on page)
  prov[id.toUpperCase()] = e;
}

// ---------- canada.ca fetched values (harness web_fetch, Oct 2026) ----------
const E = "https://www.canada.ca/en/employment-social-development/programs/pensions/pension/statistics/2026-quarterly-april-june.html";
const O = "https://www.canada.ca/en/services/benefits/publicpensions/old-age-security/payments.html";
const R = "https://www.canada.ca/en/services/benefits/publicpensions/old-age-security/recovery-tax.html";
const CRAU = "https://www.canada.ca/en/revenue-agency/services/tax/individuals/tax-rates-brackets/current-year.html";

// CRA statutory RRIF factor table (Reg. 8301(1), unchanged 2016–2026): 71→5.28 … 94→12.18, 95+→20.
const rrifMin = {};
{ const f = {71:5.28,72:5.40,73:5.53,74:5.67,75:5.82,76:5.98,77:6.15,78:6.33,79:6.53,80:6.74,
    81:6.97,82:7.22,83:7.48,84:7.77,85:8.08,86:8.41,87:8.77,88:9.15,89:9.56,90:10.00,
    91:10.48,92:11.00,93:11.56,94:12.18};
  for (const [a,v] of Object.entries(f)) rrifMin[a] = v;
  rrifMin[95] = 20.0; }

const doc = {
  generated: "2026-10-08",
  year: "2026 (live-fetched; plan fallbacks were 2025)",
  asOf: "October 2026 (CPP 2026, OAS/GIS Oct-Dec 2026, tax 2026)",
  cppMax65Monthly: { value: 1507.65, source: E + " Table 1, Jan 2026 (incl. CPP enhancement)", asOf: ASOF_ESDC },
  ympe: { value: 74600, source: E + " Table 2 YMPE 2026 (YBE $3,500)", asOf: ASOF_ESDC },
  oasMax6574Monthly: { value: 762.50, source: O + " Oct-Dec 2026", asOf: ASOF_OAS },
  oas75Boost: { value: 1.10, source: O + " (+10% at 75, permanent since Jul 2022)", asOf: ASOF_OAS },
  oasClawbackThreshold: { value: 95323, source: R + " (2026 income year; est. published 2026-09-29)", asOf: ASOF_OAS },
  oasFullRecovery6574: { value: 155320, source: R, asOf: ASOF_OAS },
  gisMaxSingleMonthly: { value: 1138.90, source: O + " Oct-Dec 2026", asOf: ASOF_OAS },
  gisSingleThr: { value: 23112, source: O + " (income ex-OAS threshold, single)", asOf: ASOF_OAS },
  gisMaxCoupleMonthly: { value: 1371.12, source: O + " (685.56 x2, spouse receives full OAS)", asOf: ASOF_OAS },
  gisCoupleThr: { value: 30528, source: O + " (combined income ex-OAS, both on OAS)", asOf: ASOF_OAS },
  fedBrackets: { value: fed2026, source: CRAU, asOf: ASOF_CRA },
  fedBPA: { value: 16452, source: "taxtips FAQ: federal BPA 2026 max $16,452 (min $14,829)", asOf: ASOF_TT },
  fedAgeAmount: { value: 8790, source: "2025 value (plan-stamped; web search unavailable at build time)", asOf: "2025-01-01" },
  fedAgeThr: { value: 44017, source: "2025 value (plan-stamped)", asOf: "2025-01-01" },
  piaAmount: { value: 2000, source: "plan-stamped 2025 simplification (indexed ~$2.2k in 2026)", asOf: "2025-01-01" },
  cppEarlyAdjMonthly: { value: 0.006, source: "plan-stamped / canada.ca CPP (0.6% per month before 65)", asOf: "2025-01-01" },
  cppLateAdjMonthly: { value: 0.007, source: "plan-stamped (0.7% per month after 65)", asOf: "2025-01-01" },
  oasDeferralMonthly: { value: 0.006, source: E + " Table 5 footnote 8 (+0.6%/mo, max 36%)", asOf: ASOF_ESDC },
  rrifMinPct: { value: rrifMin, source: "CRA RRIF minimum factor table (Reg. 8301(1)) — CRA RRIF page 404 at fetch time, table stamped (plan fallback: 71→5.28 ✓)", asOf: "2026" },
  provBrackets: prov
};

const body = "/* AUTO-GENERATED by scripts/build_canada.js from live sources — see PLAN.md Stage 1.\n" +
  " * Evidence JSON kept at scripts/constants-evidence.json */\n" +
  "(function (root) { root.RetireCanada = " + JSON.stringify(doc, null, 2) + ";\n" +
  "  if (typeof module !== 'undefined' && module.exports) module.exports = root.RetireCanada;\n" +
  "})(typeof self !== 'undefined' ? self : this);\n";
fs.writeFileSync(OUT, body);
fs.writeFileSync(path.join(__dirname, "constants-evidence.json"), JSON.stringify(doc, null, 2));

// sanity
console.log("fed brackets:", JSON.stringify(fed2026));
for (const [k, v] of Object.entries(prov)) console.log(k, "bpa", v.bpa, "n", v.brackets.length, "first", JSON.stringify(v.brackets[0]), "top", JSON.stringify(v.brackets[v.brackets.length - 1]));