// lib/investinglive.ts
// Scrapes Giuseppe Dellamotta's recurring rate-expectations article on investinglive.com
// URL pattern: /centralbank/how-have-interest-rate-expectations-changed-after-this-weeks-events-YYYYMMDD/ (+ fallbacks)
// Published after major market events (typically on Fridays or post-CB-decision)
//
// Data format in articleBody JSON-LD:
//   "CB: XX bps (YY% probability of rate hike/no change at the next meeting)"
// Covers all 8 CBs including SNB — the only free public source with CHF OIS-equivalent data.

import type { Currency } from "./types";

// ── CB name → Currency ────────────────────────────────────────────────────────

const CB_TO_CCY: Record<string, Currency> = {
  "fed":  "USD",
  "fomc": "USD",
  "ecb":  "EUR",
  "boe":  "GBP",
  "boj":  "JPY",
  "boc":  "CAD",
  "rba":  "AUD",
  "rbnz": "NZD",
  "snb":  "CHF",
};

// ── Types ─────────────────────────────────────────────────────────────────────

export interface ILRateExpectation {
  currency:              Currency;
  nextMeetingProbPct:    number;   // probability of change at next meeting (0–100)
  nextMeetingIsHike:     boolean;  // true = hike, false = cut (no-change → isHike stays false)
  nextMeetingIsNoChange: boolean;
  bpsYearEnd:            number;   // cumulative bps priced in by year-end
  publishedDate:         string;   // YYYY-MM-DD
}

export type ILExpectationsMap = Partial<Record<Currency, ILRateExpectation>>;

export interface ILExpectationsWithHistory {
  current:  ILExpectationsMap;
  prev:     ILExpectationsMap;
  prevDate: string | null;
}

// ── URL discovery ─────────────────────────────────────────────────────────────

interface ArticleRef { url: string; dateStr: string; daysAgo: number; }

// Teste les 4 variantes d'URL (/centralbank/ ou /news/, events pluriel ou singulier)
// en parallèle pour un jour donné — un seul aller-retour réseau au lieu de 4 séquentiels.
async function tryUrl(daysAgo: number): Promise<ArticleRef | null> {
  const d = new Date(Date.now() - daysAgo * 86_400_000);
  const yyyymmdd = d.toISOString().slice(0, 10).replace(/-/g, "");
  const dateStr  = `${yyyymmdd.slice(0,4)}-${yyyymmdd.slice(4,6)}-${yyyymmdd.slice(6,8)}`;
  const candidates = [
    `https://investinglive.com/centralbank/how-have-interest-rate-expectations-changed-after-this-weeks-events-${yyyymmdd}/`,
    `https://investinglive.com/centralbank/how-have-interest-rate-expectations-changed-after-this-weeks-event-${yyyymmdd}/`,
    `https://investinglive.com/news/how-have-interest-rate-expectations-changed-after-this-weeks-events-${yyyymmdd}/`,
    `https://investinglive.com/news/how-have-interest-rate-expectations-changed-after-this-weeks-event-${yyyymmdd}/`,
  ];
  const hits = await Promise.all(candidates.map(async (url) => {
    try {
      const res = await fetch(url, {
        method:  "GET",
        headers: { "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 Chrome/124.0.0.0 Safari/537.36" },
        cache:   "no-store",
      });
      res.body?.cancel().catch(() => {});
      return res.ok ? url : null;
    } catch { return null; }
  }));
  const found = hits.find((u): u is string => u !== null);
  return found ? { url: found, dateStr, daysAgo } : null;
}

// Cherche le jour le plus récent (daysAgo le plus petit) avec un article dans [start, end],
// par lots concurrents plutôt que séquentiellement — évite jusqu'à ~150 aller-retours
// réseau en série (risque de timeout sur les fonctions serverless Vercel).
async function findDayInRange(start: number, end: number, batchSize = 6): Promise<ArticleRef | null> {
  for (let batchStart = start; batchStart <= end; batchStart += batchSize) {
    const batchEnd = Math.min(batchStart + batchSize - 1, end);
    const days = Array.from({ length: batchEnd - batchStart + 1 }, (_, i) => batchStart + i);
    const results = await Promise.all(days.map(tryUrl));
    const found = results
      .filter((r): r is ArticleRef => r !== null)
      .sort((a, b) => a.daysAgo - b.daysAgo)[0];
    if (found) return found;
  }
  return null;
}

async function findArticleRefs(): Promise<{ current: ArticleRef | null; previous: ArticleRef | null }> {
  const current = await findDayInRange(0, 14);

  console.log(`[IL] article courant : ${current ? `day=${current.daysAgo} url=${current.url}` : "introuvable (0–14 jours)"}`);
  if (!current) return { current: null, previous: null };

  const searchFrom = current.daysAgo + 1;
  const searchTo   = current.daysAgo + 28;
  const previous = await findDayInRange(searchFrom, searchTo);

  console.log(`[IL] article précédent : ${previous ? `day=${previous.daysAgo} url=${previous.url}` : `introuvable (day ${searchFrom}–${searchTo})`}`);
  return { current, previous };
}

// ── Article fetch + parse ─────────────────────────────────────────────────────

async function fetchAndParse(ref: ArticleRef): Promise<ILExpectationsMap> {
  try {
    const res = await fetch(ref.url, {
      headers: {
        "User-Agent":      "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 Chrome/124.0.0.0 Safari/537.36",
        "Accept":          "text/html,application/xhtml+xml",
        "Accept-Language": "en-US,en;q=0.9",
      },
      next: { revalidate: 21600 },
    });
    if (!res.ok) return {};

    const html = await res.text();
    const jsonLdMatch = html.match(/"articleBody"\s*:\s*"((?:[^"\\]|\\.)*)"/);
    if (!jsonLdMatch) {
      console.warn("[IL] articleBody not found:", ref.url);
      return {};
    }

    const body = jsonLdMatch[1]
      .replace(/\\n/g, "\n")
      .replace(/\\"/g, '"')
      .replace(/\\u003c/g, "<")
      .replace(/\\u003e/g, ">");

    const result = parseArticleBody(body, ref.dateStr);
    console.log(`[IL] Parsed ${Object.keys(result).length} CBs from article dated ${ref.dateStr}`);
    return result;
  } catch (err) {
    console.error("[IL] fetch error:", err);
    return {};
  }
}

// ── Article parser ─────────────────────────────────────────────────────────────

function parseArticleBody(text: string, publishedDate: string): ILExpectationsMap {
  const result: ILExpectationsMap = {};

  // Matches: "RBNZ: 75 bps (79% probability of rate hike at the next meeting)"
  //          "Fed: 13 bps (99% probability of no change at the next meeting)"
  //          "ECB: 53 bps (99% probability of rate cut at the next meeting)"
  const linePattern = /([A-Za-z]+)\s*:\s*(-?\d+)\s*bps\s*\(\s*(\d+)%\s*probability\s+of\s+(rate\s+(?:hike|cut)|no\s+change)\s+at\s+the\s+next\s+meeting\)/gi;

  let m: RegExpExecArray | null;
  while ((m = linePattern.exec(text)) !== null) {
    const [, cbRaw, bpsStr, probStr, directionRaw] = m;
    const ccy = CB_TO_CCY[cbRaw.toLowerCase()];
    if (!ccy) continue;

    const probPct               = parseInt(probStr);
    const direction             = directionRaw.toLowerCase();
    const nextMeetingIsNoChange = direction === "no change";
    const nextMeetingIsHike     = !nextMeetingIsNoChange && direction.includes("hike");
    const nextMeetingIsCut      = !nextMeetingIsNoChange && direction.includes("cut");

    let bpsYearEnd = parseInt(bpsStr);
    if (nextMeetingIsCut && bpsYearEnd > 0) bpsYearEnd = -bpsYearEnd;

    const nextMeetingProbPct = nextMeetingIsNoChange ? 100 - probPct : probPct;

    result[ccy] = {
      currency: ccy,
      nextMeetingProbPct,
      nextMeetingIsHike,
      nextMeetingIsNoChange,
      bpsYearEnd,
      publishedDate,
    };
  }

  return result;
}

// ── Exports ───────────────────────────────────────────────────────────────────

/** Retourne uniquement l'article le plus récent (compatibilité descendante). */
export async function fetchILExpectations(): Promise<ILExpectationsMap> {
  const { current } = await findArticleRefs();
  if (!current) {
    console.warn("[IL] No recent rate-expectations article found (last 14 days)");
    return {};
  }
  return fetchAndParse(current);
}

/** Retourne l'article courant ET l'article précédent pour calcul de delta semaine/semaine. */
export async function fetchILExpectationsWithHistory(): Promise<ILExpectationsWithHistory> {
  const { current, previous } = await findArticleRefs();

  if (!current) {
    console.warn("[IL] No recent rate-expectations article found (last 14 days)");
    return { current: {}, prev: {}, prevDate: null };
  }

  const [currentData, prevData] = await Promise.all([
    fetchAndParse(current),
    previous ? fetchAndParse(previous) : Promise.resolve({} as ILExpectationsMap),
  ]);

  return { current: currentData, prev: prevData, prevDate: previous?.dateStr ?? null };
}