import type { MappedData } from '../../../domains/shared';

// Internal: Yahoo Finance API response shape
type YahooSummary = Record<string, Record<string, unknown>>;

export class DataMapper {
  // ── Public entry point ────────────────────────────────────────────────────
  static mapToStandardFormat(ticker: string, summary: YahooSummary): MappedData {
    const quoteType = summary.price?.quoteType as string | undefined;
    const category = ((summary.assetProfile?.category as string) || '').toLowerCase();
    const yieldVal = (summary.summaryDetail?.trailingAnnualDividendYield as number) ?? 0;

    const isBond =
      category.includes('bond') ||
      category.includes('fixed income') ||
      category.includes('treasury') ||
      (quoteType === 'ETF' && yieldVal > 0.02 && category === '');

    if (quoteType === 'ETF') {
      return isBond
        ? { type: 'BOND', ticker, ...DataMapper.mapBondData(summary) }
        : { type: 'ETF', ticker, ...DataMapper.mapEtfData(summary) };
    }

    return { type: 'STOCK', ticker, ...DataMapper.mapStockData(summary) };
  }

  // ── Stock ─────────────────────────────────────────────────────────────────
  private static mapStockData(summary: YahooSummary) {
    const fd = (summary.financialData ?? {}) as Record<string, number | null>;
    const ks = (summary.defaultKeyStatistics ?? {}) as Record<string, number | null>;
    const sd = (summary.summaryDetail ?? {}) as Record<string, number | null>;
    const pr = (summary.price ?? {}) as Record<string, number | null>;

    const currentPrice = pr.regularMarketPrice ?? 0;
    const sharesOutstanding = ks.sharesOutstanding ?? 0;
    const operatingCashflow = fd.operatingCashflow ?? 0;
    const freeCashflow = fd.freeCashflow ?? 0;

    // P/FFO proxy — used for REIT scoring
    const pFFO =
      operatingCashflow > 0 && sharesOutstanding > 0
        ? (currentPrice as number) / (operatingCashflow / sharesOutstanding)
        : null;

    // FCF yield — negative FCF preserved so cash-burning companies fail the gate
    const fcfYield =
      freeCashflow !== 0 && sharesOutstanding > 0 && (currentPrice as number) > 0
        ? ((freeCashflow as number) / (sharesOutstanding as number) / (currentPrice as number)) *
          100
        : null;

    // PEG: prefer Yahoo's value, fall back to trailingPE / earningsGrowth
    const yahoosPEG = ks.pegRatio ?? null;
    const trailingPE = sd.trailingPE ?? null;
    const earningsGrowth = fd.earningsGrowth != null ? (fd.earningsGrowth as number) * 100 : null;
    const computedPEG =
      trailingPE != null && earningsGrowth != null && earningsGrowth > 0
        ? +((trailingPE as number) / earningsGrowth).toFixed(2)
        : null;
    const pegRatio = yahoosPEG ?? computedPEG;

    // Quick ratio — fall back to currentRatio when missing
    const quickRatio = fd.quickRatio ?? fd.currentRatio ?? null;

    // ── 52-week movement ──────────────────────────────────────────────────
    const week52High = sd.fiftyTwoWeekHigh ?? null;
    const week52Low = sd.fiftyTwoWeekLow ?? null;
    const week52Change =
      ks['52WeekChange'] != null ? +((ks['52WeekChange'] as number) * 100).toFixed(1) : null;
    const week52FromHigh =
      week52High != null && week52High > 0 && (currentPrice as number) > 0
        ? +(((currentPrice - week52High) / week52High) * 100).toFixed(1)
        : null;
    const week52FromLow =
      week52Low != null && week52Low > 0 && (currentPrice as number) > 0
        ? +(((currentPrice - week52Low) / week52Low) * 100).toFixed(1)
        : null;

    // ── Analyst consensus ─────────────────────────────────────────────────
    const analystRating = fd.recommendationMean ?? null;
    const analystTargetPrice = fd.targetMeanPrice ?? null;
    const numberOfAnalysts =
      fd.numberOfAnalystOpinions != null ? Math.round(fd.numberOfAnalystOpinions as number) : null;
    const analystUpside =
      analystTargetPrice != null && (currentPrice as number) > 0
        ? +(((analystTargetPrice - currentPrice) / currentPrice) * 100).toFixed(1)
        : null;

    // ── Gross margin ──────────────────────────────────────────────────────
    const grossMargin =
      fd.grossMargins != null ? +((fd.grossMargins as number) * 100).toFixed(1) : null;

    // ── DCF intrinsic value ───────────────────────────────────────────────
    const revenueGrowthDecimal = fd.revenueGrowth != null ? (fd.revenueGrowth as number) : null;
    const earningsGrowthDecimal = fd.earningsGrowth != null ? (fd.earningsGrowth as number) : null;
    const dcfGrowthRate =
      earningsGrowthDecimal ?? (revenueGrowthDecimal != null ? revenueGrowthDecimal * 0.7 : null);

    const dcf = DataMapper.computeDCF(
      freeCashflow as number,
      sharesOutstanding as number,
      currentPrice as number,
      dcfGrowthRate,
    );

    return {
      peRatio: trailingPE ?? ks.forwardPE,
      trailingPE,
      pegRatio,
      priceToBook: ks.priceToBook ?? null,
      evToEbitda: ks.enterpriseToEbitda ?? null,
      grossMargin,
      netProfitMargin: fd.profitMargins != null ? (fd.profitMargins as number) * 100 : null,
      operatingMargin: fd.operatingMargins != null ? (fd.operatingMargins as number) * 100 : null,
      returnOnEquity: fd.returnOnEquity != null ? (fd.returnOnEquity as number) * 100 : null,
      revenueGrowth: fd.revenueGrowth != null ? (fd.revenueGrowth as number) * 100 : null,
      earningsGrowth,
      debtToEquity: fd.debtToEquity != null ? (fd.debtToEquity as number) / 100 : null,
      quickRatio,
      fcfYield,
      pFFO,
      dividendYield:
        sd.trailingAnnualDividendYield != null
          ? (sd.trailingAnnualDividendYield as number) * 100
          : null,
      beta: sd.beta ?? null,
      week52High,
      week52Low,
      week52Change,
      week52FromHigh,
      week52FromLow,
      marketCap: pr.marketCap ?? null,
      analystRating,
      analystTargetPrice,
      analystUpside,
      numberOfAnalysts,
      dcfIntrinsicValue: dcf?.intrinsicValue ?? null,
      dcfMarginOfSafety: dcf?.marginOfSafety ?? null,
      currentPrice,
      assetProfile: summary.assetProfile || {},
    };
  }

  // ── ETF ───────────────────────────────────────────────────────────────────
  private static mapEtfData(summary: YahooSummary) {
    return {
      expenseRatio: ((summary.summaryDetail?.expenseRatio as number) ?? 0) * 100,
      totalAssets: (summary.summaryDetail?.totalAssets as number) ?? 0,
      yield: ((summary.summaryDetail?.trailingAnnualDividendYield as number) ?? 0) * 100,
      fiveYearReturn: ((summary.defaultKeyStatistics?.fiveYearAverageReturn as number) ?? 0) * 100,
      volume:
        (summary.summaryDetail?.averageVolume as number) ??
        (summary.price?.averageVolume as number) ??
        0,
      currentPrice: (summary.price?.regularMarketPrice as number) ?? 0,
    };
  }

  // ── Bond ──────────────────────────────────────────────────────────────────
  private static mapBondData(summary: YahooSummary) {
    return {
      yieldToMaturity: ((summary.summaryDetail?.yield as number) ?? 0) * 100,
      duration: DataMapper.inferDuration(summary.assetProfile?.category as string),
      creditRating: DataMapper.inferCreditRating(summary.assetProfile?.category as string),
      currentPrice: (summary.price?.regularMarketPrice as number) ?? 0,
    };
  }

  private static inferCreditRating(category: string | undefined): string {
    const cat = (category || '').toLowerCase();
    if (cat.includes('government') || cat.includes('treasury')) return 'AAA';
    if (cat.includes('muni')) return 'AA';
    if (cat.includes('high yield') || cat.includes('junk')) return 'BB';
    if (cat.includes('corporate') || cat.includes('investment grade')) return 'A';
    return 'BBB';
  }

  private static inferDuration(category: string | undefined): number {
    const cat = (category || '').toLowerCase();
    if (cat.includes('short') || cat.includes('ultrashort') || cat.includes('1-3')) return 2;
    if (cat.includes('intermediate') || cat.includes('3-7') || cat.includes('3-10')) return 5;
    if (cat.includes('long') || cat.includes('10+') || cat.includes('20+')) return 18;
    if (cat.includes('target maturity') || cat.includes('defined maturity')) return 4;
    return 6;
  }

  // ── DCF ───────────────────────────────────────────────────────────────────
  // Two-stage model:
  //   Stage 1 — FCF/share grows at `growthRate` for 5 years, discounted at 9.5% WACC.
  //   Stage 2 — Terminal value via Gordon Growth Model at 2.5% perpetuity rate.
  // Only fires when TTM FCF per share is positive.
  private static computeDCF(
    freeCashflow: number,
    sharesOutstanding: number,
    currentPrice: number,
    growthRate: number | null,
    riskFreeRate = 0.04,
  ): { intrinsicValue: number; marginOfSafety: number } | null {
    if (!freeCashflow || freeCashflow <= 0) return null;
    if (!sharesOutstanding || sharesOutstanding <= 0) return null;
    if (!currentPrice || currentPrice <= 0) return null;

    const fcfPerShare = freeCashflow / sharesOutstanding;
    if (fcfPerShare <= 0) return null;

    const discountRate = riskFreeRate + 0.055; // WACC proxy
    const terminalGrowth = 0.025; // long-run GDP growth
    const years = 5;
    const g = Math.min(Math.max(growthRate ?? 0.08, -0.05), 0.3);

    let pv = 0;
    let fcfT = fcfPerShare;
    for (let t = 1; t <= years; t++) {
      fcfT *= 1 + g;
      pv += fcfT / Math.pow(1 + discountRate, t);
    }

    const terminalValue = (fcfT * (1 + terminalGrowth)) / (discountRate - terminalGrowth);
    pv += terminalValue / Math.pow(1 + discountRate, years);

    const intrinsicValue = +pv.toFixed(2);
    const marginOfSafety = +(((intrinsicValue - currentPrice) / intrinsicValue) * 100).toFixed(1);

    return { intrinsicValue, marginOfSafety };
  }
}