import { defineConnector, parseXml, raw, type NormalizedBatch, type ProposedInstrument } from "@market-atlas/connector-sdk";
import type { InstrumentHint, NormalizedObservation } from "@market-atlas/market-model";
import { zonedTimeToUtc } from "@market-atlas/market-model";

const URL = "https://home.treasury.gov/resource-center/data-chart-center/interest-rates/pages/xml?data=daily_treasury_yield_curve&field_tdr_date_value_month=";
const TENORS: Array<[string, string, string]> = [
  ["BC_1MONTH", "US1M", "US Treasury 1-month"],
  ["BC_2MONTH", "US2M", "US Treasury 2-month"],
  ["BC_3MONTH", "US3M", "US Treasury 3-month"],
  ["BC_4MONTH", "US4M", "US Treasury 4-month"],
  ["BC_6MONTH", "US6M", "US Treasury 6-month"],
  ["BC_1YEAR", "US1Y", "US Treasury 1-year"],
  ["BC_2YEAR", "US2Y", "US Treasury 2-year"],
  ["BC_3YEAR", "US3Y", "US Treasury 3-year"],
  ["BC_5YEAR", "US5Y", "US Treasury 5-year"],
  ["BC_7YEAR", "US7Y", "US Treasury 7-year"],
  ["BC_10YEAR", "US10Y", "US Treasury 10-year"],
  ["BC_20YEAR", "US20Y", "US Treasury 20-year"],
  ["BC_30YEAR", "US30Y", "US Treasury 30-year"],
];
const hint = (symbol: string, name: string): InstrumentHint => ({ assetClass: "TREASURY", name: `${name} par yield`, exchangeId: null, currency: "USD", country: "US", securityType: "PAR_YIELD", metadata: { featured: ["US2Y", "US10Y", "US30Y", "US3M"].includes(symbol), unit: "percent" } });
const seeds: ProposedInstrument[] = TENORS.map(([, s, n]) => ({ symbol: s, hint: hint(s, n), aliases: [s.replace("US", "US "), `${s.slice(2)} treasury`] }));

const month = (d: Date) => `${d.getUTCFullYear()}${String(d.getUTCMonth() + 1).padStart(2, "0")}`;

/** U.S. Treasury daily par yield curve (official XML/OData feed). Publishes once per business day after ~15:30 ET. */
export const usTreasuryYieldCurve = defineConnector({
  metadata: {
    id: "us-treasury-yield-curve",
    name: "U.S. Treasury — daily par yield curve",
    version: "1.0.0",
    sourceId: "us-treasury",
    organization: "U.S. Department of the Treasury",
    sourceType: "XML",
    jurisdiction: "US",
    rightsStatus: "OFFICIAL_OPEN_DATA",
    realtimeStatus: "END_OF_DAY",
    expectedLatencyMs: null,
    supportsStreaming: false,
    supportsHistorical: true,
    assetClasses: ["TREASURY"],
    exchanges: [],
    homepage: "https://home.treasury.gov/resource-center/data-chart-center/interest-rates/TextView?type=daily_treasury_yield_curve",
    description: "Daily Treasury par yield curve rates (1 month → 30 years) from the official Treasury XML feed. One value per tenor per business day.",
    rightsNotes: "U.S. federal government work — public domain.",
    termsUrl: "https://home.treasury.gov/subfooter/terms-of-use",
    sourceFamily: "us-treasury",
    enabled: true,
  },
  seeds,
  defaultSymbols: seeds.map((s) => s.symbol),
  rateLimits: { "home.treasury.gov": 0.5 },
  schedule: { intervalMs: 60 * 60_000 },
  async poll(ctx) {
    const now = new Date();
    const out = [];
    const cur = await ctx.http.getText(URL + month(now), { timeoutMs: 30_000 });
    if (!cur.notModified) out.push(raw("us-treasury-yield-curve", "us-treasury", "month", cur.text, { month: month(now) }));
    // Early in the month the current file may hold < 2 rows → also read the previous month for PREVIOUS_CLOSE.
    if ((cur.text.match(/<entry>/g) ?? []).length < 2) {
      const prevMonth = new Date(Date.UTC(now.getUTCFullYear(), now.getUTCMonth() - 1, 1));
      const prev = await ctx.http.getText(URL + month(prevMonth), { timeoutMs: 30_000 });
      out.unshift(raw("us-treasury-yield-curve", "us-treasury", "month", prev.text, { month: month(prevMonth) }));
    }
    return out;
  },
  normalize(r): NormalizedBatch {
    if (r.kind !== "month" || typeof r.payload !== "string") return { observations: [] };
    const doc = parseXml<any>(r.payload);
    const entries: any[] = doc?.feed?.entry ? (Array.isArray(doc.feed.entry) ? doc.feed.entry : [doc.feed.entry]) : [];
    const rows = entries
      .map((e) => e?.content?.["m:properties"])
      .filter(Boolean)
      .map((p: Record<string, unknown>) => ({ date: text(p["d:NEW_DATE"]), values: Object.fromEntries(TENORS.map(([k]) => [k, num(p[`d:${k}`])])) }))
      .filter((row) => row.date)
      .sort((a, b) => a.date!.localeCompare(b.date!));
    const last = rows[rows.length - 1];
    const prev = rows[rows.length - 2];
    if (!last) return { observations: [] };
    const observations: NormalizedObservation[] = [];
    for (const [key, symbol, name] of TENORS) {
      const v = last.values[key];
      if (v == null) continue;
      const ts = zonedTimeToUtc(`${last.date!.slice(0, 10)}T15:30:00`, "America/New_York");
      const base = { symbol, instrumentHint: hint(symbol, name), currency: "USD", observationType: "REFERENCE_RATE" as const, sourceTimestamp: ts, timestampTrust: "SOURCE" as const, rightsStatus: "OFFICIAL_OPEN_DATA" as const, realtimeStatus: "END_OF_DAY" as const, meta: { date: last.date!.slice(0, 10) } };
      observations.push({ ...base, field: "YIELD", value: v }, { ...base, field: "LAST_PRICE", value: v });
      const pv = prev?.values[key];
      if (pv != null) observations.push({ ...base, field: "PREVIOUS_CLOSE", value: pv, meta: { date: prev!.date!.slice(0, 10) } });
    }
    return { observations, stats: { rows: rows.length } };
  },
  fixturesDir: "fixtures",
});

function text(v: unknown): string | null {
  if (v == null) return null;
  if (typeof v === "string") return v;
  if (typeof v === "object" && typeof (v as Record<string, unknown>)["#text"] === "string") return (v as Record<string, string>)["#text"]!;
  return null;
}
function num(v: unknown): number | null {
  const t = text(v);
  if (t == null || t === "") return null;
  const n = Number(t);
  return Number.isFinite(n) ? n : null;
}