Squeeze or new positions

// Big candles labelled by what drove them: a rally that bought back shorts (a squeeze) or one that
// opened longs, a drop that sold out longs (a flush) or one that opened shorts. A candle is big when
// its body is more than `size` times the 14-bar ATR. Each trade is sorted by its change in open
// interest (`oiDelta`), as Opening and closing flow does.
indicator('Squeeze or new positions', { overlay: true, shortName: 'Squeeze' });

const size = input.float('Body over ATR', 1.5, { min: 0.1, step: 0.1 });

const chart = bars();
const tape = trades();
const atr = ta.atr(14);
const opening = tally();
const closing = tally();
const marks = plot.markers('Drivers');

tape.onTrade((t) => {
  if (isNa(t.oiDelta) || t.oiDelta === 0) return;
  (t.oiDelta > 0 ? opening : closing).add(t.side === 'buy' ? t.notional : -t.notional);
});

chart.onClose(() => {
  // Updated on every bar, before any return: an indicator only advances when `update` runs.
  const range = atr.update(chart);
  const body = chart.close - chart.open;
  if (!tape.available || !(Math.abs(body) > size * range)) return;
  const up = body > 0;
  // In the direction of the candle: positions closed against positions opened.
  const exits = up ? closing.value : -closing.value;
  const entries = up ? opening.value : -opening.value;
  const squeeze = exits > entries;
  const text = up ? (squeeze ? 'Squeeze' : 'New longs') : (squeeze ? 'Flush' : 'New shorts');
  const ink = up ? color.up : color.down;
  marks.add({ position: up ? 'above' : 'below', shape: squeeze ? 'diamond' : 'circle', text, color: squeeze ? ink : color.withAlpha(ink, 0.6) });
});