Opens and closes footprint

// Who opened and who closed at each price: four lanes from each fill's `takerWhy`. Taker selling on the
// left (longs closing nearest the candle, new shorts outside), taker buying on the right (shorts
// closing, then new longs). A flip opens the other way, so it counts as an open. New shorts and new
// longs are opposed: where one is three times the other at a price, the footprint marks it.
indicator('Opens and closes footprint', { overlay: true, shortName: 'Opens and closes' });

const tape = trades();
const fp = plot.footprint('Opens and closes', {
  lanes: [
    { id: 'longsClosing', label: 'Longs closing', side: 'left', color: '#e48b66' },
    { id: 'newShorts', label: 'New shorts', side: 'left', color: color.down },
    { id: 'shortsClosing', label: 'Shorts closing', side: 'right', color: '#39b2b6' },
    { id: 'newLongs', label: 'New longs', side: 'right', color: color.up },
  ],
  opposed: [{ a: 'newShorts', b: 'newLongs' }],
  stats: ['newShorts', 'longsClosing', 'shortsClosing', 'newLongs'],
});

tape.onTrade((t) => {
  const why = t.takerWhy;
  if (why === 'open_short' || why === 'flip_ls') fp.add('newShorts', t.price, t.size);
  else if (why === 'tp_long' || why === 'stop_long') fp.add('longsClosing', t.price, t.size);
  else if (why === 'tp_short' || why === 'stop_short') fp.add('shortsClosing', t.price, t.size);
  else if (why === 'open_long' || why === 'flip_sl') fp.add('newLongs', t.price, t.size);
});