/**
 * 전략평가 차트 — 선택 봉 기준 N봉 추세선 Drawing 생성
 */
import type { Drawing } from '../types';
import type { OHLCVBar } from '../types';
import type { BacktestSettingsDto, StrategyDto } from './backendApi';
import type { ConditionDSL, LogicNode } from './strategyTypes';
import { trendLineConfigFromSettings, trendLineSegmentAt, trendLineKindForCross, isTrendLinePriceScaleField } from './trendLineGeometry';
import { calculateIndicator } from './indicatorRegistry';
import { DSL_TO_REGISTRY } from './strategyToChartIndicators';

function walkTrendLineConditions(
  node: LogicNode | null | undefined,
  side: 'buy' | 'sell',
  out: Array<{ side: 'buy' | 'sell'; cond: ConditionDSL }>,
): void {
  if (!node) return;
  if (node.type === 'TIMEFRAME') {
    node.children?.forEach(c => walkTrendLineConditions(c, side, out));
    return;
  }
  if (node.type === 'NOT') {
    const child = node.children?.[0];
    if (child) walkTrendLineConditions(child, side, out);
    return;
  }
  if (node.type === 'AND' || node.type === 'OR') {
    node.children?.forEach(c => walkTrendLineConditions(c, side, out));
    return;
  }
  if ((!node.type || node.type === 'CONDITION') && node.condition) {
    const ct = node.condition.conditionType;
    if (ct === 'TREND_LINE_CROSS_UP' || ct === 'TREND_LINE_CROSS_DOWN') {
      out.push({ side, cond: node.condition });
    }
  }
}

function registryType(dslType: string): string {
  return DSL_TO_REGISTRY[dslType] ?? dslType;
}

function isPriceScaleField(field?: string): boolean {
  if (!field) return true;
  const f = field.toUpperCase();
  return f.includes('CLOSE') || f.includes('PRICE') || f.includes('HIGH') || f.includes('LOW')
    || f.includes('OPEN') || f.includes('MA') || f.includes('EMA')
    || f.includes('UPPER') || f.includes('MIDDLE') || f.includes('LOWER')
    || f.includes('BAND') || f.includes('DC_');
}

async function resolveSourceValues(
  bars: OHLCVBar[],
  cond: ConditionDSL,
  getParams: (type: string) => Record<string, number | string | boolean>,
): Promise<number[] | null> {
  const lf = (cond.leftField ?? 'CLOSE_PRICE').toUpperCase();
  if (lf === 'CLOSE_PRICE' || lf === 'CURRENT') {
    return bars.map(b => b.close);
  }
  if (lf === 'HIGH_PRICE') return bars.map(b => b.high);
  if (lf === 'LOW_PRICE') return bars.map(b => b.low);
  if (lf === 'OPEN_PRICE') return bars.map(b => b.open);

  const regType = registryType(cond.indicatorType);
  try {
    const params = { ...getParams(regType), ...(cond.params ?? {}) };
    const { plots } = await calculateIndicator(regType, bars, params);
    const plotKeys = Object.keys(plots);
    if (plotKeys.length === 0) return null;

    let plotKey = plotKeys[0]!;
    if (lf.includes('K') && plots.plot0) plotKey = 'plot0';
    else if (lf.includes('SIGNAL') && plots.plot1) plotKey = 'plot1';
    else if (lf.includes('MACD') && plots.plot0) plotKey = 'plot0';
    else if (lf.includes('UPPER') && plots.plot2) plotKey = 'plot2';
    else if (lf.includes('LOWER') && plots.plot0) plotKey = 'plot0';
    else if (lf.includes('MIDDLE') && plots.plot1) plotKey = 'plot1';

    const plot = plots[plotKey as keyof typeof plots];
    if (!plot || !Array.isArray(plot)) return null;
    const byTime = new Map(plot.map((p: { time: number; value: number }) => [p.time, p.value]));
    return bars.map(b => {
      const v = byTime.get(b.time);
      return v != null && Number.isFinite(v) ? v : NaN;
    });
  } catch {
    return bars.map(b => b.close);
  }
}

/** 선택 봉(barIndex) 기준 추세선만 반환 — 시그널 전체 순회하지 않음 */
export async function buildSignalTrendLineDrawings(opts: {
  bars: OHLCVBar[];
  /** 캔들 선택봉 인덱스 */
  barIndex: number;
  strategy: StrategyDto | null;
  settings?: BacktestSettingsDto | null;
  getParams: (type: string) => Record<string, number | string | boolean>;
}): Promise<Drawing[]> {
  const { bars, barIndex, strategy, settings, getParams } = opts;
  if (!strategy || bars.length === 0 || barIndex < 0 || barIndex >= bars.length) return [];

  const conditions: Array<{ side: 'buy' | 'sell'; cond: ConditionDSL }> = [];
  walkTrendLineConditions(strategy.buyCondition as LogicNode | null, 'buy', conditions);
  walkTrendLineConditions(strategy.sellCondition as LogicNode | null, 'sell', conditions);
  if (conditions.length === 0) return [];

  const priceConds = conditions.filter(c => isPriceScaleField(c.cond.leftField));
  if (priceConds.length === 0) return [];

  const config = trendLineConfigFromSettings(settings);
  const barTimes = bars.map(b => b.time);
  const drawings: Drawing[] = [];

  const sourceCache = new Map<string, number[]>();
  for (const { cond } of priceConds) {
    const key = `${cond.indicatorType}:${cond.leftField}:${JSON.stringify(cond.params ?? {})}`;
    if (!sourceCache.has(key)) {
      const values = await resolveSourceValues(bars, cond, getParams);
      if (values) sourceCache.set(key, values);
    }
  }

  for (const { side, cond } of priceConds) {
    const cacheKey = `${cond.indicatorType}:${cond.leftField}:${JSON.stringify(cond.params ?? {})}`;
    const sourceValues = sourceCache.get(cacheKey);
    if (!sourceValues) continue;

    const lookback = Math.max(2, cond.lookbackPeriod ?? config.defaultLookback);
    const kind = trendLineKindForCross(cond.conditionType, side);
    const priceScale = isTrendLinePriceScaleField(cond.leftField);
    const seg = trendLineSegmentAt(
      barTimes, sourceValues, bars, barIndex, lookback, config, kind, priceScale,
    );
    if (!seg) continue;

    const id = `tl-${barIndex}-${side}-${cond.conditionType}-${lookback}-${config.mode}`;
    drawings.push({
      id,
      type: 'trendline',
      points: [
        { time: seg.startTimeSec, price: seg.startPrice },
        { time: seg.endTimeSec, price: seg.endPrice },
      ],
      color: side === 'buy' ? '#26a69a' : '#ef5350',
      lineWidth: 2,
      style: 'dashed',
      visible: true,
    });
  }

  return drawings;
}