import { YahooClient } from './YahooClient.js';
import { REGIME } from '../config/constants.js';

const TTL_MS = 60 * 60 * 1000;

const DEFAULTS = {
  sp500Price: 5000,
  riskFreeRate: 4.5,
  vixLevel: 20,
  rateRegime: REGIME.HIGH,
  volatilityRegime: REGIME.NORMAL,
  benchmarks: { marketPE: 22, techPE: 30, reitYield: 3.5, igSpread: 1.0 },
};

const rateRegime = (rate) => (rate < 2 ? REGIME.LOW : rate <= 5 ? REGIME.NORMAL : REGIME.HIGH);
const volRegime = (vix) => (vix < 15 ? REGIME.LOW : vix <= 25 ? REGIME.NORMAL : REGIME.HIGH);

const pe = (summary) =>
  summary.summaryDetail?.trailingPE ?? summary.defaultKeyStatistics?.forwardPE;

export class BenchmarkProvider {
  // logger: object with .warn() — defaults to console so CLI behaviour is unchanged.
  constructor({ logger = console } = {}) {
    this.client = new YahooClient();
    this.cache = { data: null, expiresAt: 0 };
    this.logger = logger;
  }

  async getMarketContext() {
    if (this.cache.data && Date.now() < this.cache.expiresAt) return this.cache.data;

    try {
      const [sp500, tn10y, vix, spy, xlk, xlre, lqd] = await Promise.all([
        this.client.fetchSummary('^GSPC'),
        this.client.fetchSummary('^TNX'),
        this.client.fetchSummary('^VIX'),
        this.client.fetchSummary('SPY'),
        this.client.fetchSummary('XLK'),
        this.client.fetchSummary('XLRE'),
        this.client.fetchSummary('LQD'),
      ]);

      const riskFreeRate = tn10y.price?.regularMarketPrice ?? 0;
      const sp500Price = sp500.price?.regularMarketPrice ?? 0;
      const vixLevel = vix.price?.regularMarketPrice ?? 0;

      if (!sp500Price || !riskFreeRate) throw new Error('Invalid market data (zero values)');

      const lqdYield = (lqd.summaryDetail?.trailingAnnualDividendYield ?? 0) * 100;

      const context = {
        sp500Price,
        riskFreeRate,
        vixLevel,
        rateRegime: rateRegime(riskFreeRate),
        volatilityRegime: volRegime(vixLevel),
        benchmarks: {
          marketPE: pe(spy) ?? 22,
          techPE: pe(xlk) ?? 30,
          reitYield: (xlre.summaryDetail?.trailingAnnualDividendYield ?? 0.035) * 100,
          igSpread: Math.max(0.1, lqdYield - riskFreeRate),
        },
        timestamp: new Date().toISOString(),
      };

      this.cache = { data: context, expiresAt: Date.now() + TTL_MS };
      return context;
    } catch (err) {
      this.logger.warn('Market data fetch failed, using defaults:', err.message);
      return this.cache.data ?? DEFAULTS;
    }
  }
}