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// HTF Power of 3 — SXVNT SDK
// Projects the last N HTF candles to the right of price action.
// Most recent candle gets dashed connectors showing where O/H/L/C
// occurred on the LTF chart. Each candle shows its hour label.

function calculate(bars, ctx) {
  // ═══ Inputs ═══
  const htfTimeframe = ctx.input('HTF', '1H');
  const numCandles = ctx.input('Candles', 5, { min: 1, max: 5, step: 1 });
  const rightOffset = ctx.input('Right Offset', 8, { min: 5, max: 50, step: 1 });
  const candleWidth = ctx.input('Candle Width', 6, { min: 3, max: 12, step: 1 });
  const candleGap = ctx.input('Candle Gap', 3, { min: 1, max: 8, step: 1 });
  const bullColor = ctx.input('Bull Color', '#089981');
  const bearColor = ctx.input('Bear Color', '#f23645');
  const showLabels = ctx.input('Price Labels', true);
  const showDelta = ctx.input('Show Delta', true);

  // ═══ Get HTF data (non-repainting) ═══
  const htf = ctx.request(htfTimeframe);
  const last = bars.length - 1;
  if (last < 0 || htf.bars.length === 0) return;

  // ═══ Collect candles to draw (confirmed + forming) ═══
  const f = htf.forming;
  const formingCount = f ? (f.endBar - f.startBar + 1) : 0;
  const hasForming = f && formingCount >= 3;

  const displayCandles = [];
  const confirmedToShow = hasForming ? numCandles - 1 : numCandles;
  const startFrom = Math.max(0, htf.bars.length - confirmedToShow);
  for (let i = startFrom; i < htf.bars.length; i++) {
    const b = htf.bars[i];
    displayCandles.push({
      o: b.open, h: b.high, l: b.low, c: b.close, vol: b.volume,
      sBar: b.startIdx, eBar: b.endIdx, ts: b.timestamp, isForming: false,
    });
  }
  if (hasForming) {
    displayCandles.push({
      o: f.open, h: f.high, l: f.low, c: f.close, vol: f.volume,
      sBar: f.startBar, eBar: f.endBar, ts: f.timestamp, isForming: true,
    });
  }
  if (displayCandles.length === 0) return;

  // ═══ Draw each candle ═══
  for (let ci = 0; ci < displayCandles.length; ci++) {
    const d = displayCandles[ci];
    const isLast = ci === displayCandles.length - 1;

    // ── Position ──
    const startX = last + rightOffset + ci * (candleWidth + candleGap);
    const endX = startX + candleWidth;
    const midX = Math.round((startX + endX) / 2);
    const isBull = d.c >= d.o;
    const color = isBull ? bullColor : bearColor;

    // ── Wick ──
    ctx.line(midX, d.h, midX, d.l, { color, lineWidth: 2 });

    // ── Body ──
    ctx.box(startX, Math.max(d.o, d.c), endX, Math.min(d.o, d.c), {
      fillColor: color, borderColor: color,
    });

    // ── Hour label above candle ──
    const dt = new Date(d.ts);
    const hourStr = String(dt.getHours());
    ctx.label(midX, d.h, hourStr, {
      color: 'transparent', textColor: '#787b86', size: 10,
      position: 'above', style: 'none',
    });

    // ── Delta volume below candle ──
    if (showDelta && d.sBar >= 0 && d.eBar < bars.length) {
      let delta = 0;
      for (let i = d.sBar; i <= d.eBar; i++) {
        if (bars[i].close > bars[i].open) delta += bars[i].volume;
        else if (bars[i].close < bars[i].open) delta -= bars[i].volume;
      }
      const sign = delta > 0 ? '+' : '';
      const abs = Math.abs(delta);
      let deltaStr;
      if (abs >= 1e6) deltaStr = sign + (delta / 1e6).toFixed(1) + 'M';
      else if (abs >= 1000) deltaStr = sign + (delta / 1000).toFixed(1) + 'K';
      else deltaStr = sign + Math.round(delta).toString();
      ctx.label(midX, d.l, deltaStr, {
        textColor: delta >= 0 ? bullColor : bearColor,
        size: 9, position: 'below', style: 'none',
      });
    }

    // ── Connectors + price labels on rightmost candle only ──
    if (isLast) {
      let hIdx = d.sBar, lIdx = d.sBar;
      if (d.sBar >= 0 && d.eBar < bars.length) {
        for (let i = d.sBar; i <= d.eBar; i++) {
          if (bars[i].high >= d.h) hIdx = i;
          if (bars[i].low <= d.l) lIdx = i;
        }
      }

      ctx.line(d.sBar, d.o, startX, d.o, {
        color: '#787b86', lineWidth: 1, lineStyle: 'dashed',
      });
      ctx.line(hIdx, d.h, midX, d.h, {
        color: bullColor, lineWidth: 1, lineStyle: 'dashed',
      });
      ctx.line(lIdx, d.l, midX, d.l, {
        color: bearColor, lineWidth: 1, lineStyle: 'dashed',
      });
      ctx.line(last, d.c, endX, d.c, {
        color, lineWidth: 1, lineStyle: 'dashed',
      });

      if (showLabels) {
        const labelX = endX + 1;
        ctx.label(labelX, d.h, 'High ' + d.h.toFixed(2), {
          textColor: bullColor, size: 10, position: 'at',
          style: 'none', textAlign: 'left',
        });
        ctx.label(labelX, d.c, 'Close ' + d.c.toFixed(2), {
          textColor: color, size: 10, position: 'at',
          style: 'none', textAlign: 'left',
        });
        ctx.label(labelX, d.o, 'Open ' + d.o.toFixed(2), {
          textColor: '#787b86', size: 10, position: 'at',
          style: 'none', textAlign: 'left',
        });
        ctx.label(labelX, d.l, 'Low ' + d.l.toFixed(2), {
          textColor: bearColor, size: 10, position: 'at',
          style: 'none', textAlign: 'left',
        });
      }

      ctx.label(midX, d.l, htfTimeframe, {
        color: 'transparent', textColor: '#787b86', size: 11,
        position: 'below', style: 'none',
      });
    }
  }
}