import React, { useMemo } from 'react';
import type { BacktestAnalysis } from '../../utils/backendApi';
import BacktestSparkline from './BacktestSparkline';
import type { EquityPoint } from '../../utils/backtestEquity';
import { krw, pct, pctAbs } from '../../utils/backtestUiUtils';
import { formatUpbitKrwPrice } from '../../utils/safeFormat';

interface Props {
  analysis: BacktestAnalysis | null;
  equityCurve: EquityPoint[];
  totalReturnOverride?: number;
  winRateOverride?: number;
  tradeCountOverride?: number;
  winCountOverride?: number;
  mddOverride?: number;
  sharpeOverride?: number;
  profitFactorOverride?: number;
  netProfitOverride?: number;
  emptyText?: string;
}

const num = (v: number, dec = 2) => (isFinite(v) ? v.toFixed(dec) : '–');

const fmtWon = (v: number) =>
  isFinite(v) ? `₩${formatUpbitKrwPrice(v, '–')}` : '–';

function MetricCell({
  label,
  value,
  tone,
}: {
  label: string;
  value: React.ReactNode;
  tone?: 'up' | 'down' | 'gold' | 'neutral';
}) {
  return (
    <div className="btd-analysis-metric">
      <span className="btd-analysis-metric-label">{label}</span>
      <span className={`btd-analysis-metric-value${tone ? ` btd-analysis-metric-value--${tone}` : ''}`}>
        {value}
      </span>
    </div>
  );
}

export default function BacktestKpiPanel({
  analysis,
  equityCurve,
  totalReturnOverride,
  winRateOverride,
  tradeCountOverride,
  winCountOverride,
  mddOverride,
  sharpeOverride,
  profitFactorOverride,
  netProfitOverride,
  emptyText = '분석 결과를 선택하세요.',
}: Props) {
  const positive = useMemo(() => {
    const ret = totalReturnOverride ?? analysis?.totalReturnPct ?? 0;
    return ret >= 0;
  }, [analysis, totalReturnOverride]);

  if (!analysis && totalReturnOverride == null) {
    return <div className="btd-analysis-empty">{emptyText}</div>;
  }

  const totalReturn = totalReturnOverride ?? analysis?.totalReturnPct ?? 0;
  const winRate = winRateOverride ?? analysis?.winRate ?? 0;
  const tradeCount = tradeCountOverride ?? analysis?.numberOfPositions ?? 0;
  const winCount = winCountOverride ?? analysis?.numberOfWinning ?? Math.round(tradeCount * winRate);
  const lossCount = analysis?.numberOfLosing ?? Math.max(0, tradeCount - winCount);
  const breakEven = analysis?.numberOfBreakEven ?? Math.max(0, tradeCount - winCount - lossCount);
  const mdd = mddOverride ?? analysis?.maxDrawdownPct ?? 0;
  const sharpe = sharpeOverride ?? analysis?.sharpeRatio ?? 0;
  const profitFactor = profitFactorOverride ?? (
    analysis && analysis.grossLoss !== 0
      ? Math.abs(analysis.grossProfit / analysis.grossLoss)
      : analysis?.profitLossRatio ?? 0
  );
  const netProfit = netProfitOverride ?? analysis?.totalProfitLoss ?? 0;
  const initialCap = analysis?.initialCapital ?? 0;
  const finalEquity = analysis?.finalEquity ?? initialCap + netProfit;
  const grossProfit = analysis?.grossProfit ?? 0;
  const grossLoss = analysis?.grossLoss ?? 0;
  const avgWin = winCount > 0 ? grossProfit / winCount : 0;
  const avgLoss = lossCount > 0 ? grossLoss / lossCount : 0;
  const buyHold = analysis?.buyAndHoldReturnPct ?? 0;
  const vsHold = analysis?.vsBuyAndHold ?? 0;
  const maxRunup = analysis?.maxRunupPct ?? 0;
  const sortino = analysis?.sortinoRatio ?? 0;
  const calmar = analysis?.calmarRatio ?? 0;
  const var95 = analysis?.valueAtRisk95 ?? 0;
  const es = analysis?.expectedShortfall ?? 0;
  const plRatio = analysis?.profitLossRatio ?? profitFactor;
  const recovery = mdd !== 0 ? totalReturn / Math.abs(mdd) : 0;

  return (
    <div className="btd-analysis-stack">
      <section className="btd-analysis-card btd-analysis-card--profit">
        <header className="btd-analysis-card-head">
          <h3 className="btd-analysis-card-title">수익성</h3>
          <span className="btd-analysis-card-tag">Profitability</span>
        </header>
        <div className="btd-analysis-card-body">
          <div className="btd-analysis-hero">
            <div className="btd-analysis-hero-main">
              <span className="btd-analysis-hero-label">총 수익률</span>
              <strong className={`btd-analysis-hero-value ${totalReturn >= 0 ? 'up' : 'down'}`}>
                {pct(totalReturn)}
              </strong>
            </div>
            <BacktestSparkline curve={equityCurve} positive={positive} width={80} height={30} />
          </div>
          <div className="btd-analysis-grid">
            <MetricCell label="초기 자본" value={fmtWon(initialCap)} />
            <MetricCell label="최종 자산" value={fmtWon(finalEquity)} tone={finalEquity >= initialCap ? 'up' : 'down'} />
            <MetricCell label="순이익" value={krw(netProfit)} tone={netProfit >= 0 ? 'up' : 'down'} />
            <MetricCell label="평균 수익률" value={pct(analysis?.avgReturnPct ?? 0)} tone={(analysis?.avgReturnPct ?? 0) >= 0 ? 'up' : 'down'} />
            <MetricCell label="총 이익 (Gross)" value={krw(grossProfit)} tone="up" />
            <MetricCell label="총 손실 (Gross)" value={krw(-Math.abs(grossLoss))} tone="down" />
            <MetricCell label="Buy & Hold" value={pct(buyHold)} tone={buyHold >= 0 ? 'up' : 'down'} />
            <MetricCell label="vs Buy & Hold" value={num(vsHold, 2)} tone={vsHold >= 1 ? 'up' : 'down'} />
          </div>
        </div>
      </section>

      <section className="btd-analysis-card btd-analysis-card--risk">
        <header className="btd-analysis-card-head">
          <h3 className="btd-analysis-card-title">리스크 관리</h3>
          <span className="btd-analysis-card-tag">Risk</span>
        </header>
        <div className="btd-analysis-card-body">
          <div className="btd-analysis-hero btd-analysis-hero--compact">
            <div className="btd-analysis-hero-main">
              <span className="btd-analysis-hero-label">MDD (최대낙폭)</span>
              <strong className="btd-analysis-hero-value down">{pct(mdd)}</strong>
            </div>
            <div className="btd-analysis-hero-side">
              <span className="btd-analysis-side-label">Max Runup</span>
              <strong className="btd-analysis-side-value up">{pct(maxRunup)}</strong>
            </div>
          </div>
          <div className="btd-analysis-grid">
            <MetricCell label="Sharpe Ratio" value={num(sharpe)} tone="gold" />
            <MetricCell label="Sortino Ratio" value={num(sortino)} tone="gold" />
            <MetricCell label="Calmar Ratio" value={num(calmar)} tone="gold" />
            <MetricCell label="Recovery Factor" value={num(recovery)} tone={recovery >= 1 ? 'up' : 'neutral'} />
            <MetricCell label="VaR (95%)" value={pct(var95)} tone="down" />
            <MetricCell label="Expected Shortfall" value={pct(es)} tone="down" />
          </div>
        </div>
      </section>

      <section className="btd-analysis-card btd-analysis-card--stats">
        <header className="btd-analysis-card-head">
          <h3 className="btd-analysis-card-title">거래 통계</h3>
          <span className="btd-analysis-card-tag">Trades</span>
        </header>
        <div className="btd-analysis-card-body">
          <div className="btd-analysis-hero btd-analysis-hero--compact">
            <div className="btd-analysis-hero-main">
              <span className="btd-analysis-hero-label">승률</span>
              <strong className={`btd-analysis-hero-value ${winRate >= 0.5 ? 'up' : 'down'}`}>
                {pctAbs(winRate, 1)}
              </strong>
            </div>
            <div className="btd-analysis-hero-side">
              <span className="btd-analysis-side-label">총 거래</span>
              <strong className="btd-analysis-side-value">{tradeCount}회</strong>
            </div>
          </div>
          <div className="btd-analysis-grid">
            <MetricCell label="승리" value={`${winCount}회`} tone="up" />
            <MetricCell label="패배" value={`${lossCount}회`} tone="down" />
            <MetricCell label="무승부" value={`${breakEven}회`} tone="neutral" />
            <MetricCell label="체결 비율" value={tradeCount > 0 ? pctAbs(winCount / tradeCount, 0) : '0%'} tone="gold" />
            <MetricCell label="평균 수익" value={krw(avgWin)} tone="up" />
            <MetricCell label="평균 손실" value={krw(-Math.abs(avgLoss))} tone="down" />
            <MetricCell label="Profit Factor" value={num(profitFactor)} tone={profitFactor >= 1 ? 'up' : 'down'} />
            <MetricCell label="손익비 (P/L)" value={num(plRatio)} tone="gold" />
          </div>
          <p className="btd-analysis-footnote">
            총 {tradeCount}회 · 승 {winCount} / 패 {lossCount}
            {breakEven > 0 ? ` / 무 ${breakEven}` : ''}
            · PF {num(profitFactor)}
          </p>
        </div>
      </section>
    </div>
  );
}